Getting the most out the RTis

2

Comments

  • gp4jesusgp4jesus Posts: 1,163
    forgot a few things - sorry for a partial duplicate post

    2 dedicated systems or 1 dual purpose?
    XO upgrades, regardless of mild* to wild**, will raise your Tweeter Happiness Meter (THM).
    * swap just the tweeter's series cap w/ an inexpensive Dayton audio cap, about $8 plus shipping
    ** VR3 or Westmassguy does all minus inductors - several hundred $

    Replace the Polk metal jumpers w/short pieces of speaker wire. Any leftovers from connecting the A7s?

    I encourage others to chime in here: I believe your AVR may bear a small amount of the cause to your low THM reading as I've read "they're bright" many times.

    I almost forgot. The Polk website info omits one little, teeny, tiny, itty, bitty piece of, what I believe is, VERY important info about the RTi A7: the 125hz XO spec is in fact a LP filter only. The mid does NOT have ANY HP filtering. Yes you read that right. The woofers and the mid are in parallel w/each other below 125hz - 4 ohm load to your amp*; a nasty issue for most AVR's power amp section. IMHO these along w/ the A9s are prime candidates for bi-amping! See the 3rd post in my "Tri-amp A7" thread. My disciple, JCsound, kinda followed my (bi-amp) lead - the rest is for another discussion.
    * a non-issue for your NAD** or most any other separate amp.
    ** my first amp* (integrated) was a NAD as was a cassette deck, turntable, and tuner***
    *** still have, still work!

    I could & would gladly, by phone, discuss the rest as I see so many points, certainly more than I have time for.

    Tony

    Samsung 60" UN60ES6100 LED
    Outlaw Audio 975 Pre/Pro
    Samsung BDP, DirecTV Rcvr, Xbox 360, Dennon LDP, Phillips CD chgr

    Canare 14 ga - LCR tweeters inside; CC outside
    BJC 10 ga - LCR mids, inside & out
    8 ga Powerline - LR woofers, inside & out

    LR: tri-amped RTi A7. Woofers, Rotel 98X amp; M & T, P'sound HCA-1000
    CC: Rotel RB985 -> tri-amped CSi A6
    5 Audio Pro Subs: 1 B1.39: 1 Evidence at each corner
    Surrounds: Hafler XL280 -> AR 12 ga -> RTi A3*
    Power Conditioning & Distribution:
    3 dedicated 20A feeds; APC H15; 4 Furman Miniport 20s
    *Bi-amped by years end
  • PolkNAD17PolkNAD17 Posts: 25
    @Clipdat, thanks for the kind words :smile: Hopefully this thread has been helpful to others besides myself (and those actively participating)!

    @gp4jesus, your work on the RTi crossovers is very impressive! I've been considering all of the excellent suggestions made so far...and originally, the thought of modifying the A7s seemed like a fun, affordable way to possibly refine the sound a bit. But someone made a comment a few posts ago that buying speakers designed closer to my musical tastes is better than buying a speaker that does not suite my tastes, and trying to take it apart/modify it. It's like teaching a fish to climb a tree...it's just not designed for it.

    So, with that said, I've been doing some preliminary price-checking/sale-hunting online...there are some LSiM 705s on the Polk Audio Ebay Store (as well as some 703s I believe). I also found several sales on brand new Focal Aria speakers, including a place nearby that sells Focal, among other brands. I already heard the Focal Arias - they have a very smooth, balanced, acoustic sound to them (anything but harsh) - they have a more subdued sound compared to the A7s, less shimmer, less bite...but I think I'll give them another listen one day soon and decide from there what I want to do. I'm still searching for a place that carries the LSiM line. The problem with Polk is that they are not considered "high end" like B&W, Focal, REL, etc., etc., and even though the LSiM was designed to compete with these brands, a lot of the local audio stores don't carry Polk in their lineup. :neutral: On top of that, the LSiMs are too expensive to sell a more mainstream audio store, where people are looking for entire home theater systems at $1,000 or less... Polk is kind of stuck between a rock and a hard place with the LSiMs.

    But to answer your question, I am not sure if I will build two separate systems or just one all-purpose system. It seems more and more likely that I will only have one all-purpose system for at least the short term (i.e., a few years). With that said, the Focal Arias or Polk LSiM really fit the bill for a dual-purpose setup...the RTis are good for HT, but too harsh for music. The Focal Electras are way too expensive, and because they've been replaced by the Kanta line, the only way to get Electra speakers is on the used market (good for cost savings...but bad for availability (Electra line sits firmly in the "last speakers you'll ever buy" category)). This is not to say the LSiM or Arias are bad, or that buying them implies compromise; but for those of you who have had the opportunity to hear the Electras (or Sopras/Utopias) know they are absolutely pristine in their musical reproduction (and they should be for the price!) - detailed and smooth, never a hint of sharpness, music sounds live, holographic, great depth & sound stage, no sibilance, punchy/accurate/deep bass...the floorstanders are much the same, except the sound stage is a bit bigger (bass extension is similar, based on my 4-hr listening session). Anyway, they're great speakers. I preferred the Electras to the B&W 802 D3 floorstanders...B&W are great too, but the Focals had more personality...I mean even the RTis with their infamous stinging treble, are very lively, fun, and involving speakers - the B&W 800 series are incredibly accurate, but incredibly clinical...they never really drew me in. As I listened, I was in awe of the unprecedented control, presence, accuracy, and spaciousness the speakers imbued...these are the qualities every great speaker should possess, but to these ears, the B&W 800 series are all theory...they lack soul.

    Anyway, that concludes my rant for the evening. In a nutshell, I am very likely going to sell my RTi setup and replace it with the LSiMs (if I can find a place that carries them) or Focal Arias (i.e., replace the A7s with the 926). Estimated time frame is this spring - or - if I can convince my wife, maybe in the next few weeks :wink: Thanks again for all the advice/suggestions, I will keep you posted! ::thumbs up::
    Home Theater:
    Preamp: Yamaha RX-A1020
    Amp: NAD M27
    Speakers: Polk Rti A7, Polk CSi A6, Polk Rti A4
    Subs: (2) Polk DSW 660
    Other: MiniDSP 2x4 HD (external crossover)
  • PolkNAD17PolkNAD17 Posts: 25
    @gp4jesus - I was replying to your second post, and I accidentally deleted everything...no option to "undo" for some reason. $@%&;^*! computer gremlins :neutral:

    I'll be brief...the system will be a dual-purpose system...having two sound systems is not in the cards right now (one day, maybe?) - I think the LSiMs or Focal Arias will serve very well as the main speakers in a dual-purpose sound system.

    I have leftover speaker wire/cable, but I'm using banana plugs...there isn't any extra room, and I can use spades because the binding post caps don't close all the way.

    Agreed regarding the AVR...but I think that would be my last upgrade. First, I need to address the treble sharpness (i.e., by replacing the RTis with something more to my tastes); then, I want to upgrade to dual subs (more spaciousness/depth in music & added low-end oomph for movies); lastly, upgrade the AVR to a dedicated preamplifier for added control, refinement, and extracting every last ounce of musicality from the system. AVRs are like Swiss army knives...they are designed to do several things, but are not really dedicated to do any one thing very well. For day-to-day stuff it works great, it will get you out of a bind, but it doesn't replace a dedicated toolbox. For casual listeners, AVRs are an excellent choice...but for more serious listeners, AVRs have some drawbacks. I'm more of a casual listener myself, and the Yamaha AVR served me very well...but its lack of power was immediately noticeable from day 1. Yea the Polks were powered, but the dynamics were pretty flat, lacked depth & sparkle...just very, utilitarian. Even as a casual listener I could tell something was missing, but that's just me. My friends and family loved the speakers running off the AVR. To each his own.

    The NAD M27 was a blind purchase...I read about it, but there are hardly any user reviews. Still, it seemed to fit all of my requirements...small size, efficient, ample power, 5+ channels...I also considered Parasound A51, Classe AMP5, and McIntosh MC205, but all were too large and/or too expensive. I was able to get a good deal on the NAD, so I jumped on it. So far no complaints - it is very detailed, highly resolving, balanced, smooth, excellent control - and yet I actually attribute these characteristics to the speakers...the amp enables the speakers to do their thing...after all, I'm listening to the speakers, not the amp. Of course, in the end, the A7s failed to live up to their goal of serving in a dual-purpose sound system. Hopefully Polk gets it right whenever it replaces the RTi line with a new "Reference Theater" speaker line up.

    Oh yea, I learned after I bought the M27 that it is actually a fully balanced design...so is the M17 preamplifier (probably why it is so expensive...2x the parts!) I'm using unbalanced RCAs from the Yamaha AVR, but the speakers are dead quiet...even with the volume turned up 100% (music paused), there isn't even the faintest hiss...just blackness. I imagine replaced the unbalanced RCAs with balanced XLRs (rx-a1020 offers unbalanced RCA preouts only), the dynamics would improve, as would the soundstage depth and width. I read about class A/B amplifiers exhibiting various degrees of audible hiss, regardless of brand (Krell, McIntosh, Bryston owners all talk about speaker hiss)...so I'm curious if an added benefit of class D amplifiers is that they are so noise-free...or less susceptible to accumulating noise...or maybe I am just super lucky to have a quiet system? I don't know. I'm not using a dedicated 20-amp line haha, it's a shared 15-amp line with upgraded electrical receptacles, powering 3 gaming systems, a TV, AVR, amp, subwoofer, and several lights. I'm lucky regarding the noise...but the truth with the 15-amp limit is that none of these components - singularly or combined - will pull more than a few sustained amps, or even peak/instantaneous amps enough to trip a 15-amp breaker. A dedicated 20-amp line offers nice overhead and peace of mind, but I doubt it's really necessary except in more extreme setups...or if you're having noise issues with your other outlets. As always, YMMV.

    I said I would be brief...I failed. I tried to stay on subject...I failed. Have a great evening folks.
    Home Theater:
    Preamp: Yamaha RX-A1020
    Amp: NAD M27
    Speakers: Polk Rti A7, Polk CSi A6, Polk Rti A4
    Subs: (2) Polk DSW 660
    Other: MiniDSP 2x4 HD (external crossover)
  • gp4jesusgp4jesus Posts: 1,163
    PolkNAD17:
    F1nut's XO work is very impressive. Hunt down his "Having Fun w/RTi A series speakers" thread for more pics & details.

    My LCR are tri-amped as in "no passive filtering" - all active save for 68uf DC blocking caps on the tweeters*, I plan to upgrade* after finishing the rest** of the big stuff - likely by years end. Surround** channels up next/last to bi-amp.

    Side note: the other big item for me, something that may be of interest to you is the just-released Outlaw Audio 976* prepro. 7.2 w/balanced & unbalanced outputs for all channels. Each channel including the sub outs, has its own 10 channel full parametric EQ. You can set them manually or use the calibration software & mic.

    https://www.outlawaudio.com/products/976.html?gclid=EAIaIQobChMIlPvyoY282AIVwbjACh14EgHdEAAYASAAEgIW5fD_BwE

    * I LOVE the 975 that the 976 replaces. 975 is way better than the Rotel 1068 I had before that.

    Enjoy your journey. Folks on this forum will gladly help you along regardless of your chosen path.

    Tony
    Samsung 60" UN60ES6100 LED
    Outlaw Audio 975 Pre/Pro
    Samsung BDP, DirecTV Rcvr, Xbox 360, Dennon LDP, Phillips CD chgr

    Canare 14 ga - LCR tweeters inside; CC outside
    BJC 10 ga - LCR mids, inside & out
    8 ga Powerline - LR woofers, inside & out

    LR: tri-amped RTi A7. Woofers, Rotel 98X amp; M & T, P'sound HCA-1000
    CC: Rotel RB985 -> tri-amped CSi A6
    5 Audio Pro Subs: 1 B1.39: 1 Evidence at each corner
    Surrounds: Hafler XL280 -> AR 12 ga -> RTi A3*
    Power Conditioning & Distribution:
    3 dedicated 20A feeds; APC H15; 4 Furman Miniport 20s
    *Bi-amped by years end
  • cfrizzcfrizz Posts: 13,004
    [quote="gp4jesus;c-2370691...Side note: the other big item for me, something that may be of interest to you is the just-released Outlaw Audio 976* prepro. 7.2 w/balanced & unbalanced outputs for all channels. Each channel including the sub outs, has its own 10 channel full parametric EQ. You can set them manually or use the calibration software & mic.

    https://www.outlawaudio.com/products/976.html?gclid=EAIaIQobChMIlPvyoY282AIVwbjACh14EgHdEAAYASAAEgIW5fD_BwE

    * I LOVE the 975 that the 976 replaces. 975 is way better than the Rotel 1068 I had before that.

    Enjoy your journey. Folks on this forum will gladly help you along regardless of your chosen path. Tony[/quote]

    Tony, are you planning to upgrade to the 976? If so, please do a review, I'm interested in how it performs.
    Sunfire TGP III PrePro, Sunfire Cinema Grand Signature 405wpc 5 ch. Amp, Oppo 103 BluRay, Rotel RCD-1072 CDP, Sony Bravia KDL-40R510C TV, Polk S60 Main Speakers, Boston VR-920 Center Channel, SVS NSD-12 SB12 Subwoofer, Polk DSW 400 Subwoofer, Polk FXi-3 Surround Speakers
  • Airplay355Airplay355 Posts: 4,248
    I’m interested in the 976 as well. I’ve got a 975 now but it would be nice to have hdcp 2
  • gp4jesusgp4jesus Posts: 1,163
    cfrizz wrote: »
    "gp4jesus wrote: »

    https://www.outlawaudio.com/products/976.html?gclid=EAIaIQobChMIlPvyoY282AIVwbjACh14EgHdEAAYASAAEgIW5fD_BwE

    * I LOVE the 975 that the 976 replaces. 975 is way better than the Rotel 1068 I had before that.

    Tony, are you planning to upgrade to the 976? If so, please do a review, I'm interested in how it performs.
    Yes but not right away. If you don't mind a little reading and can't wait for me, the link below will take you to the Outlaw Saloon/976 section.

    http://saloon.outlawaudio.com/ubbthreads/ubbthreads.php?ubb=postlist&Board=83&page=1

    Look for the "Initial impressions" thread. Several had 975s and are stoked that an untweaked 976 IS an upgrade.

    Tony

    Samsung 60" UN60ES6100 LED
    Outlaw Audio 975 Pre/Pro
    Samsung BDP, DirecTV Rcvr, Xbox 360, Dennon LDP, Phillips CD chgr

    Canare 14 ga - LCR tweeters inside; CC outside
    BJC 10 ga - LCR mids, inside & out
    8 ga Powerline - LR woofers, inside & out

    LR: tri-amped RTi A7. Woofers, Rotel 98X amp; M & T, P'sound HCA-1000
    CC: Rotel RB985 -> tri-amped CSi A6
    5 Audio Pro Subs: 1 B1.39: 1 Evidence at each corner
    Surrounds: Hafler XL280 -> AR 12 ga -> RTi A3*
    Power Conditioning & Distribution:
    3 dedicated 20A feeds; APC H15; 4 Furman Miniport 20s
    *Bi-amped by years end
  • gp4jesusgp4jesus Posts: 1,163
    Airplay355 wrote: »
    I’m interested in the 976 as well. I’ve got a 975 now but it would be nice to have hdcp 2
    what did your 975 replace & why?I needed HDMI connectivity & the aging Rotel was dying a slow death one channel at a time. Further, an unexpected bonus, SQ!

    Samsung 60" UN60ES6100 LED
    Outlaw Audio 975 Pre/Pro
    Samsung BDP, DirecTV Rcvr, Xbox 360, Dennon LDP, Phillips CD chgr

    Canare 14 ga - LCR tweeters inside; CC outside
    BJC 10 ga - LCR mids, inside & out
    8 ga Powerline - LR woofers, inside & out

    LR: tri-amped RTi A7. Woofers, Rotel 98X amp; M & T, P'sound HCA-1000
    CC: Rotel RB985 -> tri-amped CSi A6
    5 Audio Pro Subs: 1 B1.39: 1 Evidence at each corner
    Surrounds: Hafler XL280 -> AR 12 ga -> RTi A3*
    Power Conditioning & Distribution:
    3 dedicated 20A feeds; APC H15; 4 Furman Miniport 20s
    *Bi-amped by years end
  • Airplay355Airplay355 Posts: 4,248
    It replaced a Marantz receiver that died a slow painful death as well. The display never quite worked correctly and then it started overheating (driving some SDA2B). I bought a model 5000 and 975 and a bunch of used Lsi. Now the Marantz is destined for the E-waste bin and the SDAs are in the closet.

    I like the 975 for the most part. There are a few quirks that I don't like but it serves me well and was $300 used.
  • PolkNAD17PolkNAD17 Posts: 25
    Update (possible epiphany)...

    Earlier this week I decided to run my A7s as "small" instead of "large" in lieu of the midrange driver lacking a high-pass filter at 120Hz. With all speakers set to "small" in the Yamaha AVR, crossed at 80Hz to subwoofer, I proceeded to listen to music like normal throughout the week.

    Well, to my surprise, the sharpness in the tweeter is mostly, if not completely, absent. I don't know if I am experiencing a placebo effect, or if that sting in the treble is actually gone now... If crossing the mids at 80Hz really alleviated the problem, I am thinking that the midrange woofer was probably breaking up below 80Hz, exasperating some nth order harmonic distortion(s) in the upper registers. If this is the case, the issue is not with the tweeter, but with the midrange driver. I will continue listening to movies / music like normal over the next few weeks...if I notice any discomfort or harshness I will be sure to report back.

    Just to be clear, I know it is widely recommended to run large tower speakers as "small" in order to utilize the crossover in the AVR...obviously a large powered subwoofer will provide better sub-80Hz bass than a few 7" passive woofers w/ shared power signal. But changing the A7s from "large" to "small" didn't impact the lower frequency sounds much...during movies the midbass drivers helped alleviate some of the nulls/peaks in the room...so turning on the 80Hz crossover for the A7s brought some of those nulls/peaks back to the fore. It's fine, the A7s full range were just a band-aid until I was able to add a 2nd subwoofer. Otherwise, it's hard to say if clarity in the midrange improve, although I'm sure it probably has even if I'm not detecting it. Certainly the midrange and midbass drivers are moving a bit less with the 80Hz crossover engaged.

    Which brings me to my final point. The midbass drivers have a built-in 120Hz low-pass filter. When powered by the AVR, I had the A7s set to "small" at 80Hz, and the midbass drivers barely moved...if I felt the rubber surround/speaker cone, it's like there was no energy present (in fairness, when powered by the AVR and run full range, the midbass drivers were never adequately powered). Anyway, with the NAD amp in place, the midbass drivers are still pushing out a fair amount of bass even with the 80Hz filter engaged. I honestly don't feel I am missing anything by running the A7s "small".

    All in all, I am pleasantly surprised by the change in sound from the A7s...I will keep you guys posted going forward - although the results are positive so far, I think it's still too early to consider this case closed...stay tuned. :smile:
    Home Theater:
    Preamp: Yamaha RX-A1020
    Amp: NAD M27
    Speakers: Polk Rti A7, Polk CSi A6, Polk Rti A4
    Subs: (2) Polk DSW 660
    Other: MiniDSP 2x4 HD (external crossover)
  • gp4jesusgp4jesus Posts: 1,163
    PolkNAD17 wrote: »
    Earlier this week I decided to run my A7s as "small" instead of "large"... With all speakers set to "small" in the Yamaha AVR, crossed at 80Hz to subwoofer, I proceeded to listen to music like normal throughout the week.
    experimenting, good.
    PolkNAD17 wrote: »
    ...the sharpness in the tweeter is mostly, if not completely, absent. I don't know if I am experiencing a placebo effect, or if that sting in the treble is actually gone now... If crossing the mids at 80Hz really alleviated the problem, I am thinking that the midrange was probably breaking up below 80Hz, exasperating some nth order harmonic distortion(s) in the upper registers.
    possible... ...but unlikely. You're well aware the A7s are 4 ohms from 120Hz down to the program's (movie sound track or music) lowest frequencies. HP'd @ 80 shifts the hardest part of the sub-120hz load of your speakers to the sub.

    That said, your AVR has "less work to do," w/the sub doing the "heavier lifting" hence less distortion all around. For sure your AVR's amp section has "less work to do," w/the sub doing the "heavier lifting" hence less distortion.

    Known by many that frequent these threads, when most systems are near their limit or taxed w/a load impedance below its rating - is your AVR rated to 4 ohms? Oddly enough it's the top end that manifests distress first.

    Many AVRs are rated to 6 ohms making a bit more power. The good ($$) ones like most separate amps* are rated to 4 ohms, making more power. A few* are rated to 2 ohms making even more but they're $$$ plus few & far between.

    Not to brag but I avoid all those issues & problems w/triamped A7s - each driver* has its own VERY robust channel**.
    * tweets & woofers 4 ohms; mids 8 ohms.
    ** 120, 180, or 200 watts per driver on tap depending upon same

    Keep us posted, Tony
    Samsung 60" UN60ES6100 LED
    Outlaw Audio 975 Pre/Pro
    Samsung BDP, DirecTV Rcvr, Xbox 360, Dennon LDP, Phillips CD chgr

    Canare 14 ga - LCR tweeters inside; CC outside
    BJC 10 ga - LCR mids, inside & out
    8 ga Powerline - LR woofers, inside & out

    LR: tri-amped RTi A7. Woofers, Rotel 98X amp; M & T, P'sound HCA-1000
    CC: Rotel RB985 -> tri-amped CSi A6
    5 Audio Pro Subs: 1 B1.39: 1 Evidence at each corner
    Surrounds: Hafler XL280 -> AR 12 ga -> RTi A3*
    Power Conditioning & Distribution:
    3 dedicated 20A feeds; APC H15; 4 Furman Miniport 20s
    *Bi-amped by years end
  • PolkNAD17PolkNAD17 Posts: 25
    AVR (preamp) & external amp
    @gp4jesus just to be clear, I am using my Yamaha AVR as a preamp, and a NAD M27 external amplifier to power all 5 RTi speakers (A7, CSiA6,FXi A4) . The M27 is rated at 4 & 8 ohms, but capable of 2 ohms as long as the speakers are at least 4-ohm nominal. NAD uses modified Hypex NCore modules rated at 250 watts each, or 180 watts x 7 (all channels driven; either 8 or 4 ohms). Although the owner's manual states to use speakers rated at 4 ohms nominal at a minimum, the spec sheet also includes rated power output at 2 ohms.

    RTi midrange specs & lower limits
    But I was thinking that the midrange driver is probably making some nasty even/odd order harmonics that aren't necessarily detectable (i.e., frequency response graph), but are perceptible on a subconscious level...leading to ear strain & listening fatigue. Various even/odd order harmonic distortion is measurable, but I haven't seen any such graphs of the RTi line. Using the RTi A3 as a comparison - it uses the same 6.5" midrange driver - according to the Polk Audio website, 50Hz marks the -3dB lower limit of the speaker, with an absolute lower limit of 40Hz (unsure if this is -6dB or -10dB). Even with room gain, I suspect a 6.5" midrange driver playing from 2.8KHz to 40Hz or lower, will suffer from cone breakup no matter how good the amp is. Even more to the point, I've had my CSI A6 and FXI A4 speakers crossed at 80Hz from the beginning...if I knew the 6.5" midrange driver in the A7s wasn't high-passed at 120Hz, I definitely would have set them to "small" from the beginning, amp or no amp.

    Conclusion
    Although I don't think the M27 is a limiting factor with the A7s, I do believe the 6.5" midrange driver was being over-taxed when the A7s were set as "large". I did some more listening this evening, and while the speakers are still bright, the "sting" in the trouble was either absent or far less noticeable than previously. Unless someone has another theory to share, I am concluding that the midrange speaker breakup in the lower registers was the primary cause for treble "sting". Further, I think the treble "sting" is exacerbated by the bright nature of the RTi speaker line...in a more laid back speaker, the even/odd order harmonics would likely manifest in other nasty ways. *On a side note, I don't know where the natural breakup frequency of the silk dome tweeter occurs, but that may also play into the equation. If the silk dome tweeter's breakup frequency is within hearing range (i.e., below 20KHz), it could also contribute to the nasty "sting" in the treble. In the end, I think the midrange driver is the primary cause. Based on my recent experiences, it seems limiting the midrange driver's lower frequency extension to ~80Hz is enough to remove the "sting" from the treble (**over-driving the speakers with a clipped signal (i.e., pushing AVRs too hard) could be another contributor to the treble "sting", or other potential sound issues**).

    Bi-amping / tri-amping
    @gp4jesus one last note, I believe the RTi A7/A9 speakers would definitely benefit from active bi-amping / tri-amping. If the midrange drivers were actively high-passed at 80-120Hz, with the midbass drivers actively low-passed at the same 80-120Hz, I think the full potential of the A7/A9s would be achieved. If only Polk included a 120Hz high pass filter for the midrange drivers, the A7s could be run full range and bi-amping wouldn't be necessary.

    The future...?
    With that said, I'm currently at a crossroads. I listened to the Focal Arias again this weekend and decided that I definitely want to upgrade at some point...but not now. I am still eager to hear the LSiMs in person, but haven't found any local audio shops that carry them. Also, the idea of two separate systems is out. As a result of the demo this weekend, I now have a better understanding of how room size determines speaker size. The main living room (which is where I *would* setup a 2-channel music system) would require large floorstanding speakers (i.e., RTi A9s, LSiM 707s, etc.), which my wife would only tolerate small/discrete speakers in that room. So, the HT room will serve as a dual-purpose music/HT room. I will eventually upgrade the RTi setup to a more music-friendly speaker line...but I am not in a rush to upgrade. I'll keep an eye out for a chance to demo the LSiM series, and once I decide between the LSiMs and Focal Arias, it's just a matter of waiting for a good sale. :wink:

    As always, I will continue posting on the forum with new ideas/updates as they come to me. Thanks again to everyone for all your thoughtful suggestions, they were definitely a huge help and gave me a lot of great ideas with my setup. :sunglasses:
    Home Theater:
    Preamp: Yamaha RX-A1020
    Amp: NAD M27
    Speakers: Polk Rti A7, Polk CSi A6, Polk Rti A4
    Subs: (2) Polk DSW 660
    Other: MiniDSP 2x4 HD (external crossover)
  • Hey guys, it's been about a month since I last posted here, and wanted to give a quick update...

    Previously I had my RTi A7s running full range (e.g., set to "large" in AVR), and all other speakers (e.g., CSI A6 & FXi A4s) set to "small" and crossed at 80Hz. I mostly enjoyed the sound, except for an overly bright, fatiguing, and headache-inducing sharpness in the treble that really took the enjoyment out of listening to anything with these speakers.

    There were some excellent suggestions for reducing/eliminating the treble sharpness, but what I seem to have found is that distortion in the midrange driver was actually the culprit. I set the RTi A7s from "large" to "small" in the AVR, and using an 80Hz crossover, the sharpness in the treble vanished. The A7s still have their characteristic "bright" sound, but its no longer fatiguing. I've been running the A7s crossed at 80Hz for about a month now, and they sound great.

    Other thoughts - FYI, I am using an external amplifier (using the pre-outs on my Yamaha RX-A1020), so power/impedance are a non-issue. With the A7s crossed at 80Hz, the midbass drivers are still quite active. I experimented with a 60Hz crossover, which allowed the midbass drivers to reproduce even more bass, but I found a 60Hz crossover significantly more taxing on the midrange driver...so I decided to switch back to the 80Hz crossover setting to keep distortion to an absolute minimum. If the A7 midrange driver had a HPF, I think the A7s could be run as "large" speakers easily, or at least crossed over to a subwoofer at 40-60Hz. Why didn't Polk install a HPF on the midrange??

    DSW 660 subwoofer - At the time I bought these speakers I was living in an apartment, so I had the volume on the DSW 660 turned down (e.g., volume 20 out of 40, and +3.0dB in AVR). As a result, the DSW 660 never really produced any significant bass, which is the sound (or lack of) that I got used to. Now I am no longer living in an apartment, and after successfully dialing the RTi speakers in, I decided to experiment with the DSW. I raised the volume from 20 to 28 (side note: I set the sub up to be front-facing, so the controls are on the BOTTOM of the unit...so I actually forgot, until recently, that there was a volume control on this sub - btw, the remote control never worked from day one), and the sub finally came to life! At volume 20, the sub only made its existence apparent during loud movie explosions and big action scenes, but was pretty much silent in every other instance, including most music. At volume 28, the sub added atmosphere, depth, and punch to everything...but was still a little thin sounding. I gradually bumped the volume up to 30, 32, and 34, before eventually settling on volume 32 and lowering the AVR to +2.0dB. For my room, these settings blend the DSW 660 very well with the Polk RTIs. In a previous post, I mentioned that the DSW was weak and "boomy" - the booming bass was probably because I could only hear it during movie explosions...giving the impression it was a one-note wonder, with a very narrow frequency range...bumping the volume and running a sine sweep (in 5Hz increments, from 80Hz to 10Hz), I found the DSW 660 volume to decrease gradually as the sine sweep descends, with a noticeable INCREASE in volume between 50-60Hz, DECREASE between 40-50Hz, and another INCREASE in volume between 30-40Hz (likely due to the port tuning)...below 30Hz the bass rapidly decreases (some low-level output at 25Hz, but nothing at 20Hz or lower (e.g., subwoofer barely moves at 25Hz, and doesn't move at all at 20Hz)). With that said, the DSW 660 actually really rounds out the sound of the system, and does a great job shaking the room without any audible distortion or strain. The increases/decreases in volume could be caused by room nodes/modes, or by natural deviations in the DSW's frequency response...but despite the lack of output below 30Hz, I find the DSW 600 to supplement music and movies very well. I'm not a "basshead", but like anybody, I enjoy the sound/feeling of deep, room-filling bass. In my room, the DSW 660 provides exactly that. :sunglasses:

    Conclusion - I am very happy now with the performance of my Polk setup. I was ready to upgrade the RTis to Focal Aria or Polk LSiM speakers, but now I honestly don't see the need. I was also ready to replace the DSW 660 with dual JL Audio e-subs, but again, a single DSW 660 really provides all the bass I need at this point (that includes SQ and SPL). I only plan to upgrade this setup if 1) something breaks and needs replacement, or 2) I spot an incredible sale that is just too good to pass up. In the end, I am very impressed with the quality and output of this Polk setup - for both music and movies - and taking the time to dial everything in was 100% worth it to get these speakers operating at their full potential. ::two thumbs up:: Thanks again everyone for all your help & suggestions!
    Home Theater:
    Preamp: Yamaha RX-A1020
    Amp: NAD M27
    Speakers: Polk Rti A7, Polk CSi A6, Polk Rti A4
    Subs: (2) Polk DSW 660
    Other: MiniDSP 2x4 HD (external crossover)
  • ClipdatClipdat Posts: 4,509
    Nice, thanks for the well written update. Glad you got everything dialed in now!

    Now you can get back to what's important, enjoying your system!
    Got Dayens?
  • PolkNAD17PolkNAD17 Posts: 25
    It's been a few months since I posted, but I wanted to share some of the changes/additions I've made to the system.

    Upgrade #1 - Dual subwoofers

    A couple months ago I added a second subwoofer (DSW 660 12" ported). Both subs are located up front next to the RTi A7s, about 8-9 ft apart and 4 ft away from the side walls. When I was running just one sub, I had the volume set at 32~34 out of 40...now with dual subs, I have the volume set to 29~30 for each sub...0dB in the AVR.

    So what was the benefit of adding a second sub? Well, the bass is much smoother throughout the room...at the primary listening seat, the bass is much smoother (e.g., more linear when running sine sweeps...when listening to music, the bass is much more seamless, and just kind of invisibly reinforces the music without calling attention to itself). Speaking of sine sweeps, I noticed the frequency range now extends below 20Hz. This puzzled me...previously with one sub, the DSW 660 was only able to play down to ~25Hz before going silent (no cone movement); 30Hz was more/less the lower limit of the sub, with hardly any useful output below that point. I'm guessing the high volume (32~34 out of 40) triggered the internal subsonic filter to rise to prevent over-excursion of the driver...just a guess. Currently, the dual subs play down to 24Hz (-3dB), 20Hz (-6dB), and 18Hz (-10dB)...again, just guessing. Whatever the measurements actually are, the dual DSW 660s play smoothly down to 20Hz, but not much below that (basically no cone movement by 16-17Hz).

    Upgrade #2 - Active crossover

    Last week I added a MiniDSP 2x4 HD external active crossover to the A7s. The MiniDSP is a very powerful tool, capable of room correction, time delay, phase shift, various crossover settings, etc., but I am only using it as a crossover. The MiniDSP slots into the system between preamp and amp, like this:

    Source > Preamp > MiniDSP> Amplifier > RTi A7s

    The MiniDSP has two signal inputs, and four signal outputs. I removed the brass jumpers from the back of the A7s, and use the extra two channels from my 7-channel amplifier to power the A7 midbass drivers. The idea is to implement the high-pass filter on the midrange driver that Polk so thoughtfully left out...this way I can run the A7s full range without causing midrange distortion, and to give the midbass drivers a wider operational frequency range. I set the MiniDSP filters up as follows:

    Midrange: 80Hz high-pass filter, 36dB/octave Butterworth slope
    Midbass: 240Hz low-pass filter, 24dB/octave Butterworth slope
    Midbass: 40Hz high-pass filter, 48dB/octave Butterworth slope

    The A7s are completely stock, I didn't modify them in any way except for removing the brass jumpers on the back.

    I'm using a 240Hz filter on the midbass driver to limit wasted energy (remember, the midbass drivers have a 120Hz low-pass filter); I wanted to cut out the higher frequencies going to the amp without interfering with the 120Hz passive filter.

    The midrange drivers now play strongly down to 60~80Hz, but not much below that (which is what I wanted). The midbass drivers play comfortably down to 40Hz, but are protected below that point by the 48dB high-pass filter.

    What was the benefit? The entire frequency range is soooo smooth now! The sting in the treble is gone - the A7s still have their characteristically "bright" sound - which is totally fine - but most importantly, they are no longer fatiguing, the midrange is detailed and punchy, and the midbass drivers add oomph and depth that was missing previously. Of course, the DSW 660s provide extra oomph required for movies...but for music listening, the A7s are truly full-range now and really sound great :smile: I find myself listening at louder volumes than I ever have before just because the speakers sound so damn good. The effort/journey was well worth it.

    Bottom Line

    I am very, very pleased with the current setup, it has never sounded better...I finally achieved the sound I've been craving :sunglasses:

    Just curious - do the Signature and/or LSiM series have this issue?
    Home Theater:
    Preamp: Yamaha RX-A1020
    Amp: NAD M27
    Speakers: Polk Rti A7, Polk CSi A6, Polk Rti A4
    Subs: (2) Polk DSW 660
    Other: MiniDSP 2x4 HD (external crossover)
  • K_MK_M Posts: 1,026
    Fantastic write up!
    Look forward to more impressions.
    We have a dual sub set-up and it is far superior to a single sub. Somehow it just seems like the bass is more even, similar to what you found.
    Lsi15, Lsi9, LsiC,Rta11t,M5jr+,M4,SDA 3.1TL, SDA SRS 2.3TL, Rti6....Still listing stuff, a work in progress.
    B+W-
    Epos-
    Infinity-
    Advent-

  • gp4jesusgp4jesus Posts: 1,163
    MiniDSP brand?
    Samsung 60" UN60ES6100 LED
    Outlaw Audio 975 Pre/Pro
    Samsung BDP, DirecTV Rcvr, Xbox 360, Dennon LDP, Phillips CD chgr

    Canare 14 ga - LCR tweeters inside; CC outside
    BJC 10 ga - LCR mids, inside & out
    8 ga Powerline - LR woofers, inside & out

    LR: tri-amped RTi A7. Woofers, Rotel 98X amp; M & T, P'sound HCA-1000
    CC: Rotel RB985 -> tri-amped CSi A6
    5 Audio Pro Subs: 1 B1.39: 1 Evidence at each corner
    Surrounds: Hafler XL280 -> AR 12 ga -> RTi A3*
    Power Conditioning & Distribution:
    3 dedicated 20A feeds; APC H15; 4 Furman Miniport 20s
    *Bi-amped by years end
  • txcoastal1txcoastal1 Posts: 9,874
    2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
    Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
    Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
    Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC
  • mpitogompitogo Posts: 271
    Thanks for sharing your experiences.

    Long ago I had a Yamaha AVR with Polk RT series speakers and it was bright. Replaced the AVR with Denon and another Denon then a Marantz and finally an Onkyo receiver powering the same Polk RT speakers and the Yamaha was my least favorite and fatiguing at least to my ears.

    I’ve looked at minidsp for active bi-amp but nixed it for the idea that I’m putting in a A/D D/A in the signal path now I’m rethinking the idea. The original impetus opening up the LSiM 707. The MA5200 was just not cutting it and my suspicions where correct, I replaced the MA5200 with a C47/RB1590 and wow they really sing now. While the MA5200 was not bad I think it’s much more suited and has the muscle to drive my LSi25 with its active sub. I find the combo to complement each other. My Denon AVR4802R didn’t like the LSi25 and actually shutdown once, I think due to the 4ohm load.
    Music-2.0 Raidho D-3.1 | Audio Research Ref 40 | Jeff Roland 925 | Esoteric Grandioso K1 | Transparent Reference, IC, Speaker and Power | HRS SXR Rack
  • PolkNAD17PolkNAD17 Posts: 25
    Mpitogo - How do the RTis compare to the LSiMs? I've had my eye on the LSiMs for a long time, as a potential future upgrade...I haven't had a chance to listen to the LSiMs in person yet, but I'm curious if you found them to be a major upgrade to the RTis, in terms of both music and movies? I know what you mean about Yamaha...I haven't had the opportunity to listen to any other AVR brands, but Yamaha strikes me as very neutral / analytical, for better or worse.

    Upgrade #3 - Power Conditioner

    I've been using an 8-outlet Belkin surge protector for my system for several years. Having upgraded all of the power outlets on the circuit (15-amp), I wanted a more robust device that would 1) not impede current flow, 2) non-sacrificial surge protection, including under-voltage sags (e.g., during thunderstorms), and 3) provide isolated power banks. Before I go any further, there weren't any "noise" issues I wanted to correct - the system is very quiet, balanced, and sounds great.

    Ok, so I added a Furman Elite-15 PFi to my setup a couple days ago, and for the most part the difference between it, and the Belkin, were minimal. Per the Furman instruction manual, there is about a 2 week break-in period, so who knows what might change over the next 1.5-2 weeks. But immediately I noticed the subwoofers were louder and more robust sounding. I actually had to lower the volume on the subs again (each set at 29/40 volume)...they blend very well, and after running another sine sweep noticed the bottom end (20-35Hz) was more pronounced than previously. I imagine this is due to the "PFi" capacitor supplying 3+ amps RMS and 45+ amps peak instantaneous power.

    The other improvement I noticed was on the plasma TV - a very subtle improvement - whites pop a little more, colors are a bit more vivid, and contrast (which was already excellent) has taken on a more 3-dimensional quality...hard to describe...it's very subtle, and probably something I noticed only because I've had this TV for 5 years and am very familiar with its display properties. Like I said, the net change is positive, the picture is "smoother" and a touch more "refined".

    The last change I've noticed so far is the sound stage. The depth has improved more than the width, but it seems to have expanded a little bit in both directions. It's not night and day, but a minor improvement. I haven't noticed any change in sound quality - instruments sound the same as before (clear and defined), and sound effects in movies also sound largely the same (clear, defined, and easy to locate in "space").

    Stay tuned, these are my initial impressions and subject to change as the unit breaks in, and as I acclimate to the changes. :sunglasses:

    *One last note - I used a multimeter to test the voltage at the outlets over the course of the last week or two. I measured a consistent 124.5 volts (it may vary from day to day, depending on various factors...but the voltage is very stable). With the system on (e.g., Plasma TV, preamp, 7-channel amplifier, two subwoofers, external crossover, and any number of video games / streaming media devices), the voltage drops about 0.9 volts...that's with all 7-channels active, and the system playing at normal levels...basically, a stable 123.5 volts. I didn't see the need for a power "regenerator", but considered a voltage regulator to drop the voltage to 120 volts. Ultimately, I got a good deal on the Elite-15 PFi, and figured it was a great way to affordably test out the effects of power conditioning on my system. Also, I spoke with NAD support staff and they didn't really have a strong opinion regarding power conditioners...except to say they are helpful for some systems, and that they highly recommended power conditioners with "high current" outlets for use with preamps and amps. Again, I haven't noticed any negative side effects - mostly neutral, with a few positive changes so far. Thanks for reading!
    Home Theater:
    Preamp: Yamaha RX-A1020
    Amp: NAD M27
    Speakers: Polk Rti A7, Polk CSi A6, Polk Rti A4
    Subs: (2) Polk DSW 660
    Other: MiniDSP 2x4 HD (external crossover)
  • PolkNAD17PolkNAD17 Posts: 25
    Active bi-amping

    A few weeks ago I opened up the A7s and physically disconnected the midbass drivers from the passive crossover...the drivers are wired together, directly to the back of the binding posts. Using the MiniDSP 2x4 HD crossover, I have the A7s running as follows:

    Tweeter to midrange - unchanged (passive crossover)
    Midrange to midbass - Linkwitz-Riley 4th order crossover @ 240Hz (active)

    I originally crossed the midrange/midbass at 125Hz, following Polk's original specs...but after trying other crossover points up to 280Hz, I ultimately decided 240Hz sounded best. I also set the A7s to "small", since I'm running dual DSW 660s...crossover is set to 80Hz. With the subs turned off, the A7s sound great set to "large" - but with the subs on, I don't hear any difference between "small" and "large", so I just left them set to "small".

    Oh yea, a big shout out to gp4jesus - I discovered one of his old threads (http://forum.polkaudio.com/discussion/100364/thread-for-the-passive-xo-gurus-rti-a7/p1), which was one of the reasons I decided to try some crossover points above 125Hz. It's a good discussion, and worth your time to read if you are considering bypassing the RTi's internal crossovers.

    FYI, I'm still using a Yamaha RX-A1020 AVR as my preprocessor, and a 7-channel NAD M27 amplifier. Bi-amping the A7s lets me make use of all 7 channels on the amp.

    Impressions

    After bypassing the passive midbass crossover, the first thing I noticed was how smooth the A7's sound was...not fatiguing at all, but very relaxed and natural...the A7s still sound bright, but not in a bad way...the ear fatigue is gone. I've never listened to music through this system as much as I do now...the A7s, properly setup, are very pleasant to listen to.

    The biggest differences I've noticed are 1) punchier, more pronounced bass, 2) smoother frequency response, 3) fewer phasing issues, 4) improved depth/realism in music. The improvement is less noticeable in movies - dialogue, action scenes, etc., sound more/less the same. I need to EQ the subs, which are currently the weak point when watching movies (the DSW 660s are very peaky in the 30-50Hz range). For music, the switch to active bi-amping was a night/day difference. Considering how easy/cheap it was to rewire the midbass drivers, the upgrade was well worth it. :sunglasses:

    What's next?

    Now that the A7's are singin', the next upgrade will be adding an EQ (room correction?) to smooth out the subwoofer response (peaks). I noticed the DSW's only play down to about 18-20Hz...after 18Hz, the cones are no longer moving. They don't seem strained at those frequencies - seems to me like Polk erred on the side of caution by limiting the sub's output below 25Hz...but I suspect the drivers/amp are capable of playing down to at least 20Hz without any issues.

    Question - Is there a way to bypass/modify the subsonic filter on the DSW subs?
    Home Theater:
    Preamp: Yamaha RX-A1020
    Amp: NAD M27
    Speakers: Polk Rti A7, Polk CSi A6, Polk Rti A4
    Subs: (2) Polk DSW 660
    Other: MiniDSP 2x4 HD (external crossover)
  • gp4jesusgp4jesus Posts: 1,163
    SW subsonic filter mod? W/out a schematic, nearly impossible.

    Much of the improvements you cite “going EXO” doesn’t surprise me.

    I’m not clear how your mid-bass drivers are now wired. In series? (8 ohms) In parallel? (2 ohms eek!) If 2 ohms, that would explain greater mid-bass output. I know your NAD amp is stable to 2 ohms. W/a band limited feed (below 240hz?) helps some, too.

    Best to ya, Tony

    Samsung 60" UN60ES6100 LED
    Outlaw Audio 975 Pre/Pro
    Samsung BDP, DirecTV Rcvr, Xbox 360, Dennon LDP, Phillips CD chgr

    Canare 14 ga - LCR tweeters inside; CC outside
    BJC 10 ga - LCR mids, inside & out
    8 ga Powerline - LR woofers, inside & out

    LR: tri-amped RTi A7. Woofers, Rotel 98X amp; M & T, P'sound HCA-1000
    CC: Rotel RB985 -> tri-amped CSi A6
    5 Audio Pro Subs: 1 B1.39: 1 Evidence at each corner
    Surrounds: Hafler XL280 -> AR 12 ga -> RTi A3*
    Power Conditioning & Distribution:
    3 dedicated 20A feeds; APC H15; 4 Furman Miniport 20s
    *Bi-amped by years end
  • PolkNAD17PolkNAD17 Posts: 25
    Hey Tony - thanks for the info on the midbass drivers...how do you know they are 4 ohms? (I don't doubt you, just curious). I didn't see any writing on the drivers, and I couldn't find any info online. For some reason I assumed they were 8-ohm drivers...so I wired them in parallel :sweat_smile: I'll rewire them in series to bring the overall impedance up to 8 ohms.

    Regarding the crossover point (240Hz), I'll probably mess around with some other crossover frequencies just to hear more of what's possible...every crossover point I tried (125, 240, 260, 280Hz) was an improvement over the stock sound.

    It's a shame Polk decided to castrate the DSWs below 20-25Hz...I realize how important subsonic filters are with ported subs, but I feel like Polk should have provided a variable subsonic filter, or at least lowered the filter a few more Hz. Ironically, the A7 midbass drivers easily play below 10Hz on sine sweeps...but the DSW subwoofers are completely tapped out by 18-20Hz. :grey_question: I just don't get Polk's logic in some of these speaker designs.

    At the end of the day, a little elbow grease and some minor labor never hurt anyone - and that's all that's required to bring the A7/A9s to their full potential. Like I said, at the current price point, these speakers are a steal...if you want to upgrade from [modified] A7s, you'll need to spend $4-5k before you hear any substantial improvements, IMO.
    Home Theater:
    Preamp: Yamaha RX-A1020
    Amp: NAD M27
    Speakers: Polk Rti A7, Polk CSi A6, Polk Rti A4
    Subs: (2) Polk DSW 660
    Other: MiniDSP 2x4 HD (external crossover)
  • gp4jesusgp4jesus Posts: 1,163
    Sorry for the loooong post.
    PolkNAD17 wrote: »
    Hey Tony - thanks for the info on the midbass drivers...
    you are most welcome! Further I applaud your SUCESS equally w/your efforts. You have become a member of very small percentage of Polkies willing to “lift the hood to tinker.”
    PolkNAD17 wrote: »
    how do you know they are 4 ohms? (I don't doubt you, just curious).
    Deductive reasoning Watson! Seriously, examine the mid bass* LP XO board carefully. You’ll see the they’re* wired in series. (4+4=8). Keeping in mind Polk’s nominal 8 ohm, “add” that to ZERO HP filtering for the midrange, (assuming 8ohms), in parallel, I reasoned they* had to be 4 ohms each.

    BTW: what gauge wire did you use to connect the mid-bass drivers to their BPs? I hope you used something bigger than the lame, 18 ga Polk wire. Otherwise IME you’re “leaving performance on the table.”

    I think you’ve viewed the link below months ago - reposting for your convenience and encourage you to take another look:
    http://forum.polkaudio.com/discussion/174880/tri-amped-rti-a7#latest
    You’ll see I was anal about keeping the resistance between the amps & drivers as low as possibly practical. “...waiting for the tomatos.”
    PolkNAD17 wrote: »
    I’ll rewire them in series to bring the overall impedance up to 8 ohms.
    That will “lighten the load” considerably on your amp. Anticipate:
    a. cooler running
    b. lower output. 8 ohms versus 2 ohms WILL change your amp’s current output** versus input
    c. recalibrating your ‘A7s.
    d. higher or improved damping
    The last point is for the forum’s EEs. I’ve studied & read several articles & threads on other forums on the subject.
    ** my A7s mid-bass drivers each has its own 4ohm stable channel.

    To me, the two affecting points on damping conflict.
    1. I agree that lower connection resistance (bigger wire & binding posts, higher quality connectors, etc) equals higher damping.
    2. I’m ready for the rotten tomatoes - never mind the math & theory the EEs are quick to pitch. I disagree that higher load impedance equals higher damping.

    After I retire (4th qtr, 2019) & whittle down my Post-retirement honey-do list, I will do my own testing.
    PolkNAD17 wrote: »
    Regarding the crossover point (240Hz), I'll probably mess around with some other crossover frequencies just to hear more of what's possible...every crossover point I tried (125, 240, 260, 280Hz) was an improvement over the stock sound.
    reduced Doppler distortion @ the higher XO frequencies?
    PolkNAD17 wrote: »
    It's a shame Polk decided to castrate the DSWs below 20-25Hz...I realize how important subsonic filters are with ported subs...
    I’ll take a crack
    - Broad range eq (boost) to flatten response below natural rolloff & above subsonic HP.
    - amp damping factor may be a low priority
    - aggressive HP filter to compensate for the above compromises
    Many have DIY’d awesome ported subs w/out subsonic filtering
    PolkNAD17 wrote: »
    I feel like Polk should have provided a variable subsonic filter...
    in the hands of those less knowledgeable, Polk would have many more CS repair or driver replacements not to mention add’l R&D/$ to design & build.
    PolkNAD17 wrote: »
    Ior at least lowered the filter a few more Hz. Ironically, the A7 midbass drivers easily play below 10Hz on sine sweeps.
    Hmmmm...
    PolkNAD17 wrote: »
    IAt the end of the day, a little elbow grease and some minor labor never hurt anyone - and that's all that's required to bring the A7/A9s to their full potential.
    consider a $10 (PE Dayton) per speaker upgrade, say, just the series cap to the tweeter? You could do and/or spend a lot more of course, but I believe you haven’t used all your low $ elbow grease yet to raise your Listening Happiness meter another knotch or two.

    Enjoy! Tony
    Samsung 60" UN60ES6100 LED
    Outlaw Audio 975 Pre/Pro
    Samsung BDP, DirecTV Rcvr, Xbox 360, Dennon LDP, Phillips CD chgr

    Canare 14 ga - LCR tweeters inside; CC outside
    BJC 10 ga - LCR mids, inside & out
    8 ga Powerline - LR woofers, inside & out

    LR: tri-amped RTi A7. Woofers, Rotel 98X amp; M & T, P'sound HCA-1000
    CC: Rotel RB985 -> tri-amped CSi A6
    5 Audio Pro Subs: 1 B1.39: 1 Evidence at each corner
    Surrounds: Hafler XL280 -> AR 12 ga -> RTi A3*
    Power Conditioning & Distribution:
    3 dedicated 20A feeds; APC H15; 4 Furman Miniport 20s
    *Bi-amped by years end
  • gp4jesusgp4jesus Posts: 1,163
    Update/correction: OP got me to thinkin’ I should measure those A7 woofers (OP refers to them as mid bass) They are 8 ohm drivers. Measured w/a borrowed, accurate device for testing LL phone circuits.

    My bad. I should have measured, not assumed all these years. The CSI A6 mids are 4 ohms.

    PolkNAD17: your mid bass NAD channels are seeing 4 ohms*, not 2 ohms. Wired in series - 16 ohms. I’m certain your amp is comfortable w/that* - I would leave them be.

    Enjoy! Tony
    Samsung 60" UN60ES6100 LED
    Outlaw Audio 975 Pre/Pro
    Samsung BDP, DirecTV Rcvr, Xbox 360, Dennon LDP, Phillips CD chgr

    Canare 14 ga - LCR tweeters inside; CC outside
    BJC 10 ga - LCR mids, inside & out
    8 ga Powerline - LR woofers, inside & out

    LR: tri-amped RTi A7. Woofers, Rotel 98X amp; M & T, P'sound HCA-1000
    CC: Rotel RB985 -> tri-amped CSi A6
    5 Audio Pro Subs: 1 B1.39: 1 Evidence at each corner
    Surrounds: Hafler XL280 -> AR 12 ga -> RTi A3*
    Power Conditioning & Distribution:
    3 dedicated 20A feeds; APC H15; 4 Furman Miniport 20s
    *Bi-amped by years end
  • PolkNAD17PolkNAD17 Posts: 25
    Internal wire is 14 Gauge CCA*
    *Interestingly, since aluminum is less efficient at conducting electricity than copper, "14 gauge CCA" has a thickness equivalent to 12 gauge copper...but is only as electrically conductive as 14 gauge copper wire. I found that out the hard way when stripping the wire ends :smile:

    I've read the same thing about damping factor...higher impedance tends to yield a higher damping factor. At the same time, I read that we can't really discern between DF's above 50 or so...I don't know if that's true or not, but it's just something I read anyway. For what it's worth, I rewired one of the A7s in series...with both A7s playing (one wired in parallel, the other in series), I honestly couldn't hear a difference. The bass was slightly louder in the parallel speaker...but it could have been my imagination...it was very subtle. So I went ahead and wired both A7s in series for an effective impedance of 8 or 16 ohms. I imagine 16 ohms will be fine, but I messaged NAD Support to confirm...the amp doesn't run any cooler with the speakers wired in series...the sound quality and bass output are identical as far as I can tell. ::shrug::

    Agreed regarding the DSW 660s...I guess it makes sense why Polk designed them the way it did. Dual DSWs really improved the overall sound quality, despite the large peaks in the 30-50Hz range. I currently have both subs dialed down to 26 out of 40 (volume), which has improved bass / sub-bass cohesion for the most part (sometimes bass-heavy music/movies will sound out of balance...once I EQ those peaks I think it will be less of a problem).

    No worries on the 4 / 8 ohm confusion...I couldn't find specs anywhere online or in the Polk manual. Super lame. And of course there isn't any information printed on the speaker itself. But like I said, I couldn't hear much difference between series and parellel except that the parallel wiring seemed to be a smidge louder. If NAD says a 16-ohm nominal impedance won't hurt anything, I'll leave them wired in series.

    I am still amazed out how much better these A7s sound with active crossovers...I never listened to music so much in my life! I'm actually relieved, I was ready to pull the trigger on some LSiMs or Focal Arias...this ended up being a much cheaper alternative. On a side note, has Polk released any updates regarding potential replacements for the RTi or LSiM lines?
    Home Theater:
    Preamp: Yamaha RX-A1020
    Amp: NAD M27
    Speakers: Polk Rti A7, Polk CSi A6, Polk Rti A4
    Subs: (2) Polk DSW 660
    Other: MiniDSP 2x4 HD (external crossover)
  • gp4jesusgp4jesus Posts: 1,163
    edited August 18
    Another long one...
    PolkNAD17 wrote: »
    Internal wire is 14 Gauge CCA*
    How did you determine that & what does CCA mean? None of the wire that came in my 7s are bigger than 16 ga but yours are much (8-9 years?) newer.
    PolkNAD17 wrote: »
    ... I read that we can't really discern between DF's above 50 or so...
    Experiment at higher volumes using ear plugs and decide for yourself. I’ve read “diminishing returns” above 100 and comparison tests citing “...less or more control for this or that amp.”
    Bi/tri-amping & rewiring w/bigger gets you a lot more of the DF you paid for. For me, these days, w/so much power on tap, “cranked” has a whole new meaning w/ no popping drivers during bass-heavy passages, music or HT. BTW: my LR & surrounds are set to large. Details for another day.
    PolkNAD17 wrote: »
    I rewired one of the A7s in series...with both A7s playing (one wired in parallel, the other in series), I honestly couldn't hear a difference.
    With or w/out* the top* connected*? Easier* to hear* diffs*.
    PolkNAD17 wrote: »
    The bass was slightly louder in the parallel speaker...but it could have been my imagination...it was very subtle.
    I’d have expected a bigger diff. Learned something new.
    PolkNAD17 wrote: »
    ...the amp doesn't run any cooler with the speakers wired in series ::shrug
    Says a lot for the robust design! My woofers’ amps* stay cool all the time. Back in their bi-amp days they ran slightly to “warm.” A side note for clarity: each A7 has a 2 channel amp driving just its woofers.
    PolkNAD17 wrote: »
    If NAD says a 16-ohm nominal impedance won't hurt anything, I'll leave them wired in series.
    No chance! Some entry level gear could fail driving 4 ohm loads. And would certainly fry connected to 2 ohms.
    PolkNAD17 wrote: »
    I am still amazed out how much better these A7s sound with active crossovers...
    I’m not the least bit surprised! (forgot from previous post) And a hearty welcome to a VERY exclusive circle of VERY happy tweakers into active XOs. A total of four, I believe, on this forum. Three of the four are RTi A owners - one A9 owner & us two.
    PolkNAD17 wrote: »
    I never listened to music so much in my life! I'm actually relieved, I was ready to pull the trigger on some LSiMs or Focal Arias...this ended up being a much cheaper alternative.
    Aahh patience & diligence are their own rewards. In your case, your bank account!
    PolkNAD17 wrote: »
    On a side note, has Polk released any updates regarding potential replacements for the RTi or LSiM lines?
    Ask Polk.

    Enjoy! Tony
    Samsung 60" UN60ES6100 LED
    Outlaw Audio 975 Pre/Pro
    Samsung BDP, DirecTV Rcvr, Xbox 360, Dennon LDP, Phillips CD chgr

    Canare 14 ga - LCR tweeters inside; CC outside
    BJC 10 ga - LCR mids, inside & out
    8 ga Powerline - LR woofers, inside & out

    LR: tri-amped RTi A7. Woofers, Rotel 98X amp; M & T, P'sound HCA-1000
    CC: Rotel RB985 -> tri-amped CSi A6
    5 Audio Pro Subs: 1 B1.39: 1 Evidence at each corner
    Surrounds: Hafler XL280 -> AR 12 ga -> RTi A3*
    Power Conditioning & Distribution:
    3 dedicated 20A feeds; APC H15; 4 Furman Miniport 20s
    *Bi-amped by years end
  • PolkNAD17PolkNAD17 Posts: 25
    Sorry for the acronyms :smile: CCA is Copper-Clad Aluminum...most of the speaker wire spools you buy online or in the stores are CCA, it's cheaper than pure copper. You can tell if you are using CCA wire by looking at the cross section of the wire - it will look like copper on the outside, but the inside is a silvery color. Nothing wrong with it - aluminum wiring was used in homes for a long time - but because aluminum is ~60% as efficient at conducting electricity vs. copper, 16 gauge CCA is actually 14 gauge in diameter, but only conducts as much electricity as 16 gauge copper wire.

    I bought the A7s in 2013...but didn't add the CSi A6 and FX/i A4s until 2014 or 2015.

    Good point about ear plugs and disconnecting the midrange/tweeter...but I definitely agree, no reason to limit damping factor unnecessarily. Interesting that you run your A3s as "large" speakers - after months of tinkering, I concluded the A7s excessive brightness was coming from the midrange drivers, probably resulting from too much distortion in the low-end. You're not having any brightness issues with the A3s?

    I expected a bigger difference between parallel and series wiring...but I think the differences were minimal because the M27 is a regulated design (e.g., same power at 4 or 8 ohms). The spec sheet doesn't mention 16 ohms, so I don't know much power is output to the speakers in series. Still waiting to hear back from NAD. There would probably be a bigger difference in volume using an unregulated amp design (e.g., when 4 ohms draws 2x as much power as 8 ohms, etc.)

    On a side note, I was thinking the other day about the A9s...wiring the A9s three midbass drivers in series / parallel would yield the following:

    4-ohm drivers in parallel: 1.33 ohms
    4-ohm drivers in series: 12 ohms
    8-ohm drivers in parallel: 2.66 ohms
    8-ohm drivers in series: 24 ohms

    With the A9s, the midbass drivers must be wired correctly...if they are 4-ohm drivers, they must be wired in series...if they are 8 ohms, they should be wired in parallel (with an amp capable of powering < 4-ohm nominal load). I'm curious how Polk wires the A9 drivers from the factory, that should be pretty telling in regards to speaker impedance.

    To be honest, I'm still disappointed I had to go these lengths to get the sound from the A7s that they should have had in stock form. It wasn't the work itself (rewiring), but the process of suffering the speakers' brightness, figuring out what was causing it, devising a solution, and and then going forward with fingers crossed...very frustrating. It makes me wonder what corners Polk cut with their other products... :expressionless: I'm hoping the Signature Series is Polk's effort to relaunch itself - hopefully develop completed products within their intended price range...for instance, the RTi line feels like it was developed to a higher standard, but then Polk cut corners to reduce costs to get these speakers into the lower price bracket...if Polk did not cut those corners, the RTi line could have been sold at a higher price, but Polk would have faced stiffer competition and possibly sold fewer units. C'est la vie.
    Home Theater:
    Preamp: Yamaha RX-A1020
    Amp: NAD M27
    Speakers: Polk Rti A7, Polk CSi A6, Polk Rti A4
    Subs: (2) Polk DSW 660
    Other: MiniDSP 2x4 HD (external crossover)
  • cfrizzcfrizz Posts: 13,004
    Had you done your research BEFORE buying the RTI'As you would have found out quite quickly on here that they are bright speakers that are terrific for movies but usually too bright for music.

    But they were probably on sale for a good price and you just couldn't resist leaping before looking. But once your ears told you what you heard, you decided to rebuild them, rather than send them back.

    That's on you not Polk. Polk designed the speakers with the characteristics that they wanted them to have.
    Sunfire TGP III PrePro, Sunfire Cinema Grand Signature 405wpc 5 ch. Amp, Oppo 103 BluRay, Rotel RCD-1072 CDP, Sony Bravia KDL-40R510C TV, Polk S60 Main Speakers, Boston VR-920 Center Channel, SVS NSD-12 SB12 Subwoofer, Polk DSW 400 Subwoofer, Polk FXi-3 Surround Speakers
2
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