Enclosing the RTI A7 Upper Midrange

I recently bought a pair of RTI A7's and for the most part I am happy with them. I pulled one of the lower woofers to poke around inside and noticed the top 6.5" midrage is not isolated with it's own chamber. Has anyone tried to seal the top driver off from the bottom woofers?
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Comments

  • skrol
    skrol Posts: 3,330
    Mmmmm... I understand where you are coming from in that you would like to eliminate the influence that the lower bass drivers have on the mid-range driver. However, that would be a major deviation in the design.

    The entire cabinet was tuned as one specific volume. By adding a divider to create an upper chamber, you will create two chambers. The upper chamber volume and port would need to be tuned specifically for the 6.5" driver. Depending on the t/s parameters, it may not even be possible to optimize the new enclosure for that driver. Likewise, the lower chamber, which was tuned for the larger volume, will need to be re-tuned along with the port. Again, it may not be possible to optimize the tuning for the drivers.

    Higher end Polks have divided the cabinet into multiple chambers, ie. LSi15, LSi25, LSiM series. The drivers were chosen so that the camber volumes could be optimized.
    Stan

    Main 2ch:
    Polk LSi15 (DB840 upgrade), Parasound: P/LD-1100, HCA-1000A; Denon: DVD-2910, DRM-800A; Benchmark DAC1, Monster HTS3600-MKII, Grado SR-225i; Technics SL-J2, Parasound PPH-100.

    HT:
    Marantz SR7010, Polk: RTA11TL (RDO198-1, XO and Damping Upgrades), S4, CS250, PSW110 , Marantz UD5005, Pioneer PL-530, Panasonic TC-P42S60

    Other stuff:
    Denon: DRA-835R, AVR-888, DCD-660, DRM-700A, DRR-780; Polk: S8, Monitor 5A, 5B, TSi100, RM7, PSW10 (DXi104 upgrade); Pioneer: CT-6R; Onkyo CP-1046F; Ortofon OM5E, Marantz: PM5004, CD5004, CDR-615; Parasound C/PT-600, HCA-800ii, Sony CDP-650ESD, Technics SA 5070, B&W DM601
  • F1nut
    F1nut Posts: 49,704
    ^ THIS ^
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • Thank you for your response, but it still does not convince me it's a bad idea to experiment with. If the top driver is swapped out with another one suited toward the resulting enclosure size would that help? I am less concerned with the low end response change as I have a subwoofer doing most of the LF work. The midrange on this speaker seems lacking and when played at high volumes it winds up doing a lot of unnecessary work.
  • pitdogg2
    pitdogg2 Posts: 24,474
    Well then you're on the verge of frankinpolk. They are voiced towards home theater not 2ch audio. You're going to do all that work to completely change the voicing of the speaker. Why not look for a set of different speakers that have the voice you are looking for?
    What are you using to run them? Receiver ? Amp? If your using a receiver then it is likely running out power to power them correctly.
  • westmassguy
    westmassguy Posts: 6,850
    According to the specs: "The 6 1/2-inch midrange driver is housed in its own tuned internal enclosure for increased clarity and lifelike detail". Note the small port directly below the midrange driver.
    86bq0xycsn5s.jpg

    Upgrading the crossover components could possibly help. Then again, you may just not care for the sound of this particular model.
    Home Theater/2 Channel:
    Front: SDA-2ATL forum.polkaudio.com/discussion/143984/my-2as-finally-finished-almost/p1
    Center: Custom Built forum.polkaudio.com/discussion/150760/my-center-channel-project/p1
    Surrounds & Rears: Custom Built forum.polkaudio.com/discussion/151647/my-surround-project/p1
    Sonicaps, Mills, RDO-194s-198s, Dynamat, Hurricane Nuts, Blackhole5
    Pioneer Elite VSX-72TXV, Carver PM-600, SVS PB2-Plus Subwoofer

    dhsspeakerservice.com/
  • F1nut
    F1nut Posts: 49,704
    Upgrading the crossovers like I did returns very positive results.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • gp4jesus
    gp4jesus Posts: 1,969
    I recently bought a pair of RTI A7's and for the most part I am happy with them. I pulled one of the lower woofers to poke around inside and noticed the top 6.5" midrage is not isolated with it's own chamber. Has anyone tried to seal the top driver off from the bottom woofers?
    You're not losing your marbles. What you see is correct & I'm working on a template to do* just that*.
    According to the specs: "The 6 1/2-inch midrange driver is housed in its own tuned internal* enclosure* for increased clarity and lifelike detail".
    The web site is wrong* - has been since Polk introduced the '7.
    Note the small port directly below the midrange driver.
    So what about the port.
    nbrowser wrote: »
    Sure the dual 7s aren't separated from each other but the MW is cut off from the bass drivers.
    WMG take a closer look after you pull them apart and post pics. Either that or, by some twist of I don't know what, yours are the exception.

    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • ZLTFUL
    ZLTFUL Posts: 5,640
    Another consideration that wasn't mentioned above...what're you powering them with?

    The RTiAs really open up with good solid power fed to them. Not an AVR power but a nice 200wpc+ amp. They work with an AVR feeding them...just not up to their potential.
    "Some people find it easier to be conceited rather than correct."

    "Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
  • pitdogg2
    pitdogg2 Posts: 24,474
    pitdogg2 wrote: »
    What are you using to run them? Receiver ? Amp? If your using a receiver then it is likely running out power to power them correctly.


    yep I also asked but still have not heard.

  • westmassguy
    westmassguy Posts: 6,850
    gp4jesus wrote: »
    I recently bought a pair of RTI A7's and for the most part I am happy with them. I pulled one of the lower woofers to poke around inside and noticed the top 6.5" midrage is not isolated with it's own chamber. Has anyone tried to seal the top driver off from the bottom woofers?
    You're not losing your marbles. What you see is correct & I'm working on a template to do* just that*.
    According to the specs: "The 6 1/2-inch midrange driver is housed in its own tuned internal* enclosure* for increased clarity and lifelike detail".
    The web site is wrong* - has been since Polk introduced the '7.
    Note the small port directly below the midrange driver.
    So what about the port.
    nbrowser wrote: »
    Sure the dual 7s aren't separated from each other but the MW is cut off from the bass drivers.
    WMG take a closer look after you pull them apart and post pics. Either that or, by some twist of I don't know what, yours are the exception.

    So what? The port is there for a reason. If his cabinets don't have the internal divider, then it was either left out by accident, or Polk modified the design. If they modified the design, then the upper post serves no purpose. @nbrowser stated his had the divider.
    Home Theater/2 Channel:
    Front: SDA-2ATL forum.polkaudio.com/discussion/143984/my-2as-finally-finished-almost/p1
    Center: Custom Built forum.polkaudio.com/discussion/150760/my-center-channel-project/p1
    Surrounds & Rears: Custom Built forum.polkaudio.com/discussion/151647/my-surround-project/p1
    Sonicaps, Mills, RDO-194s-198s, Dynamat, Hurricane Nuts, Blackhole5
    Pioneer Elite VSX-72TXV, Carver PM-600, SVS PB2-Plus Subwoofer

    dhsspeakerservice.com/
  • westmassguy
    westmassguy Posts: 6,850
    nbrowser wrote: »
    I have to retract my statement, after this weekend of tearing mine completely apart to replace the crossovers and all wiring and some poly fill, there are braces but the upper chamber is not separated from the bass drivers. Bad look at first with the filler in there before. Apologies.
    Sure, make me look like and idiot now.....

    Home Theater/2 Channel:
    Front: SDA-2ATL forum.polkaudio.com/discussion/143984/my-2as-finally-finished-almost/p1
    Center: Custom Built forum.polkaudio.com/discussion/150760/my-center-channel-project/p1
    Surrounds & Rears: Custom Built forum.polkaudio.com/discussion/151647/my-surround-project/p1
    Sonicaps, Mills, RDO-194s-198s, Dynamat, Hurricane Nuts, Blackhole5
    Pioneer Elite VSX-72TXV, Carver PM-600, SVS PB2-Plus Subwoofer

    dhsspeakerservice.com/
  • gp4jesus
    gp4jesus Posts: 1,969
    edited October 2016
    Nbrowser: I forgive you. I made the same mistake my first time in.

    Concerning your re-wire - can you rewire one then listen to modded versus stock? Either way go big or go home. No smaller than 12 on the mids; 10 or a 2X of 12. Not easy I know but worth it. Your "bass" will thank you.

    WMG: don't be so hard on yourself.
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • gp4jesus
    gp4jesus Posts: 1,969
    It looked like a rib to me. My goal is fashion the divider to fit inside the rib.
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • pitdogg2
    pitdogg2 Posts: 24,474
    then it makes no sense to have a port there. IMHO... Polk on the fly changes nothing new. wonder if the first gen had the separation there that would make sense since there is a port?
  • gp4jesus
    gp4jesus Posts: 1,969
    edited October 2016
    Touché Derek(!) that's also true for the A4/A6 center speakers.

    Somehow I doubt the woofers would miss the port below the mid.

    Further I question the mid interacts w/the ports beneath the woofers.

    Finally I've tried various amp configurations w/out a sub:
    1. Full range
    2. Separate amps for top & bottom both w/very high damping factors (1000!)

    Nothing at my disposal, short of some kind of HP* filtering, will prevent that mid from bottoming out w/bass-heavy music (e.g. Donald Fagen's "The Nightfly") at high levels.
    * active bi-amping ~120-150 hz works great!

    I'm certain a divider would prevent those woofers from pushing the mid to its Xmax.

    Enjoy Tony
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • westmassguy
    westmassguy Posts: 6,850
    Very disconcerting that Polk would make mention of the tuned enclosure in their marketing material, and have the physical port there. Normally, mids are either enclosed, or have a sealed back to prevent interaction with the low frequency drivers.
    Home Theater/2 Channel:
    Front: SDA-2ATL forum.polkaudio.com/discussion/143984/my-2as-finally-finished-almost/p1
    Center: Custom Built forum.polkaudio.com/discussion/150760/my-center-channel-project/p1
    Surrounds & Rears: Custom Built forum.polkaudio.com/discussion/151647/my-surround-project/p1
    Sonicaps, Mills, RDO-194s-198s, Dynamat, Hurricane Nuts, Blackhole5
    Pioneer Elite VSX-72TXV, Carver PM-600, SVS PB2-Plus Subwoofer

    dhsspeakerservice.com/
  • pitdogg2
    pitdogg2 Posts: 24,474
    edited October 2016
    DSkip wrote: »
    Not so sure I'd subscribe to that. Look at all the RTiA series speakers. Most of them have that same port, even the bookies that are also rear-ported. It is part of the design and should be there.

    I didn't know they also had a rear port on the bookies. Then I suspect they are tuned to two different frequencies.

    Very disconcerting that Polk would make mention of the tuned enclosure in their marketing material, and have the physical port there. Normally, mids are either enclosed, or have a sealed back to prevent interaction with the low frequency drivers.

    Must 100% agree with this. BUT monkey in the details says like the "fluid Coupled" SDA's this is still a "tuned Port Enclosure" just not what we would think of 97% of the time. I like you Dave think it has "its" own sub enclosure inside.

    Bob Carver would be proud of this marketing speak >:)
  • K_M
    K_M Posts: 1,627
    edited October 2016
    Polk's literature also says this:

    "Dimensions Enclosure Type - Mid-High Array Enclosure -Type ARC port
    Dimensions Enclosure Type - Subwoofer Enclosure Type -PowerPort Plus bass venting"


    Implying the mid/high drivers are indeed in an enclosure of their own with ARC port, and the sub drivers are in another enclosure with PowerPort venting....

    Very odd.
  • pitdogg2
    pitdogg2 Posts: 24,474
    OMG it's a conspiracy.... :p
  • gp4jesus
    gp4jesus Posts: 1,969
    pitdogg2 wrote: »
    OMG it's a conspiracy.... :p
    ???

    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • pitdogg2
    pitdogg2 Posts: 24,474
    edited October 2016
    I'm just funnun is all

    We have 3 different folks with web,media and literature stuff that says the same thing.
  • pitdogg2
    pitdogg2 Posts: 24,474
    And there you have it lol
  • ken brydson
    ken brydson Posts: 8,638
    nbrowser wrote: »
    I once saw a Monitor 7 on a grassy knoll...

    I boxes no less...
  • gp4jesus
    gp4jesus Posts: 1,969
    Today the planets were in alignment, the moon the right color to allow the next phase of LR mods to include...
    pitdogg2 wrote: »
    you're on the verge of frankinpolk.
    ...a divider*! Didn't get to h'cane nuts today but I can do those while watching TV.
    ...but it still does not convince me it's a bad idea to experiment* with.
    Got one speaker done just a little while ago. I will connect, compare, post pics, & 1st impressions tomorrow in an 'A7 thread I started ~5 years ago. I will release a template* for public use pending extensive listening.
    ...when played at high volumes it winds up doing a lot of unnecessary work.
    As I posted earlier, no HP filtering on the mid.

    Until later... Tony
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • The mid range on the A9's and rti12'd are in their own enclosure though. I never thought the 7's were supposed to be.
    Oh, Listen here mister. We got no way of understandin' this world. But we got as much sense of this bird flyin in the sky. Now there is a lot that bird don't know, but it don't change the fact that the world is happening to him all the same. What I am tryin to say is, is that the course of your life, well its changing, and you don't even see it- Forest Bondurant
  • I did pull the mid drivers on both speakers to confirm and yes these are not sealed from the bottom drivers. I am definitely going to seal them and add a high pass to the crossover. Sorry I have not replied to this earlier, but thanks to those that can confirm my findings.
  • gp4jesus
    gp4jesus Posts: 1,969
    I never thought the 7's were supposed to be [separate].
    How'd you arrive at that? Web site (incorrectly) unmistakedly says they are.

    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • gp4jesus
    gp4jesus Posts: 1,969
    I am definitely going to seal them ...
    See recent posts on my "Will they soften over time?" thread for pics & ideas.
    ...and add a high pass... ...[to the mid in the] crossover.
    Shop for
    1. another amp (or two)
    2. an active XO
    Scrap the
    3. binding posts (see my thread's pics)
    4. woofers' LP filters and
    5. their crappy wire
    Solder up some 10 ga (or bigger) between the BPs & those woofers. Your bass response will thank you. Note: woofers are 4 ohm wired in series.

    While you're in there:
    1. scrap the mids crappy wire
    2. solder up some 10 or 12* ga (no smaller*)
    3. for a few $s, replace a cap or 2 to the M & T...
    ...your speakers' upper half & imaging will thank you.

    Do all the above you'll have more output from the same input.

    Mount your mids & woofers w/PE's small hurricane nut & 8-32 machine screws for See F1nut's "Fun w/RTi A series speakers" thread.

    Tony
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • pitdogg2
    pitdogg2 Posts: 24,474
    If the top driver is swapped out with another one suited toward the resulting enclosure size would that help?

    This is why I made the "frankinpolk" comment it had nothing to do with a divider.

  • gp4jesus
    gp4jesus Posts: 1,969
    edited November 2016
    PD2: I think I FrankenPolk'd one of my '7s. I hope to do same to the other over Thanksgiving.

    For more details goto Speakers forum - look for "Triamped RTi A7."
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work