an SDA based HT

HBombToo

SDA2B Fronts
CRS+ Center
Monitor 5's Rear surround

Q1)
What do you think this would sound like. This topic just popped up and after looking around at all the speakers I have I could probably pull it off.

Q2)
If I split the center channel out into two different amps to drive the CRS+ center what type of SDA effect could be expected from a mono type signal? "May be strange but something to think about anyway"

HBomb

ohskigod

has been the subject of debate (sda for ht), if you have all of the stuff, i say it is at least worth it to experiment. i certainly couldnt imagine it sounding bad. if you do try it out, i'm looking forward to your review, since i could put together almost the same set up (i dont have the crs though) but would have to break up my 2 channel system, and i am having too much fun with it to do that now (only go tthe sda 2b's a couple of months ago

rskarvan

I've thought myself of setting up a 7.1 SDA system.
Here are my thoughts.

3.1TL for the front mains.
CRS+ for the center.
Monitor 10's for the side surrounds.
Monitor 7's for the rear surrounds.
PSW650 for the sub.

I've got all the parts. Its an interesting thought.

- Ron

VR3

My Dad has the 1.2tl in his HT as you know...

Very strange sounding HT, but in a good way. The 1.2 controls a 35 foot room with ease in HT performance...

In T3, where Arnold is getting dragged through the buildings -- that was coming from the front yard. SOUNDED AWESOME

SDA, setup right - is spectacular for home theater. IMO

hoosier21

Should sound great, the CRS+'s being fed a mono signal to both will not do anything "SDA" but it will timber match the 2B's.

You got the gear, go ahead and give a spin and see how you like.

Russ

DarqueKnight

Originally posted by HBombToo
SDA2B Fronts
CRS+ Center
Monitor 5's Rear surround

Q1)
What do you think this would sound like.

I think it would sound great. I used a pair of CRS+s as center channels first with a pair of 1Cs as fronts and then with a pair of SRSs as fronts. The timbre match was excellent. I eventually replaced the CRS+s with LSiCs because I didn't like the way the CRS+s looked above my RPTV (too bulky).

HBombToo

Lets talk about the CRS+ as the center for a moment. I'm thinking the center channels sound stage could be increased by the dimensional effect. By this I mean spread across the front.

raife, I never considered putting the crs+ on the TV; however, on stands at the base of the TV with uptilt is where my imagination was going.

The 2B's as fronts... well IMHO would be cool but I have to overcome my equipment rack issue. It sits on the very left of the rptv. The monitors will probably sound much like my 55i's as surrounds except with more bass.

I'm just thinking outloud here before I get my lazy but up to do it.

I have not measured my Outlaw to find out if it is common ground(my gut says its not) but that that would be the only impediment to a pair of SDA's in the front for HT at this time.

HBomb trying to find the twin;)

DarqueKnight

Originally posted by HBombToo
Lets talk about the CRS+ as the center for a moment. I'm thinking the center channels sound stage could be increased by the dimensional effect. By this I mean spread across the front.

With a mono signal, you won't get any dimensional effect because the SDA effect depends on the amount of difference between the left and right channel. In mono mode, the sound will come from dead center between the CRS+s.

If the CRS+s are spaced far apart, then you would get a "spread effect" across the front, but this would be the same as feeding the center channel signal to the front speakers and causing a "phantom" center effect.

Originally posted by HBombToo
I never considered putting the crs+ on the TV; however, on stands at the base of the TV with uptilt is where my imagination was going.

That will work quite well and was actually my preferred placement, if I could have put the speakers under my TV instead of in front of it.

Larry Chanin

Originally posted by raife1
If the CRS+s are spaced far apart, then you would get a "spread effect" across the front, but this would be the same as feeding the center channel signal to the front speakers and causing a "phantom" center effect.

That will work quite well and was actually my preferred placement, if I could have put the speakers under my TV instead of in front of it.

Hi Raife,

I have read about comb filtering problems, when you send the same signal to identical speakers spaced apart. Apparently the two identical signals constructively and destructively reenforce one an other depending on the difference in distance between the listener(s) and each speaker. I imagine that the sound level would vary quite a bit as the listener moves right and left. In addition wouldn’t the phantom center only work for a listener in the center? Wouldn’t listeners off axis hear the dialog shifted from what the director intended?

I'm wondering whether a single CRS+ might not actually sound better?

An other thought would be stacking the two CRS+ vertically. The comb filtering would then occur up and down. Since everyone is seated the only difference in distance to the speakers between listeners would be due to slight differences in the height of their ears. As a result the sound levels shouldn't vary much from listener to listener. This arrangement should have the added advantage of not shifting the dialog right and left.

Please understand that this is all theoretical based on what I've read. I've never actually experimented with two center channel speakers.

Any thoughts?

Larry

DarqueKnight

Originally posted by Larry Chanin
I imagine that the sound level would vary quite a bit as the listener moves right and left. In addition wouldn’t the phantom center only work for a listener in the center? Wouldn’t listeners off axis hear the dialog shifted from what the director intended?

You're right. That is one of the drawbacks of a phantom center.

Originally posted by Larry Chanin
I'm wondering whether a single CRS+ might not actually sound better?

A single CRS+ sounded "thin". With a single CRS+ and no SDA input from the other speaker, only one of the midrange drivers is working. To reinforce the sound, I disconnected the SDA driver from the crossover circuit and wired it in parallel with the stereo driver. This lowered speaker impedance to 3 ohms, but my amp could handle it.

I achieved the most satisfactory sound in the center by using a co-located pair of CRS+s, each with the SDA driver wired in parallel with the stereo driver. The sound of dual CRS+s was more balanced with the SDA 1C fronts I used initially and with the SDA SRS fronts I used subsequently. The bass performance in the center was also subtantially improved using dual CRS+s.

The CRS+s were replaced with dual LSiCs only for aesthetic reasons. I had to do a little rewiring of the LSiC on right. As you are looking at the front of a LSiC, the low frequency driver is to your left and the midrange driver is to your right. Using two of these side-by-side would not result in a mirror imaged pair. The positions of the right LSiC drivers were switched in order to give me an arrangement where the midrange drivers of each LSiC was in the center and both bass drivers were on the outer edges. I had to splice in some additional wire because the midrange driver wires were not long enough to reach the new location.

Originally posted by Larry Chanin
An other thought would be stacking the two CRS+ vertically. The comb filtering would then occur up and down.

The thought of doing this never occured to me, as I was trying to reduce the overall height of the speakers above my TV. If you can stack them below your TV and tilt them up toward the listening position, this might give more favorable results than arranging them horizontally.

BobMcG

Yes, I use an SDA based HT system myself. SDA-2Bs are used at the rear but I've never tried using my CRS+s for the front center. I use a CS400i for that job as it compliments my RT3000Ps which are my front SDAs thanks to a Carver C-9. I'm free to switch back and forth and usually end up with the C-9 working for me.

bdaley6509

Make no mistake...SDA for HT is incredible.

Larry Chanin

Originally posted by raife1

A single CRS+ sounded "thin". With a single CRS+ and no SDA input from the other speaker, only one of the midrange drivers is working. To reinforce the sound, I disconnected the SDA driver from the crossover circuit and wired it in parallel with the stereo driver. This lowered speaker impedance to 3 ohms, but my amp could handle it.

I achieved the most satisfactory sound in the center by using a co-located pair of CRS+s, each with the SDA driver wired in parallel with the stereo driver. The sound of dual CRS+s was more balanced with the SDA 1C fronts I used initially and with the SDA SRS fronts I used subsequently. The bass performance in the center was also subtantially improved using dual CRS+s.

The CRS+s were replaced with dual LSiCs only for aesthetic reasons. I had to do a little rewiring of the LSiC on right. As you are looking at the front of a LSiC, the low frequency driver is to your left and the midrange driver is to your right. Using two of these side-by-side would not result in a mirror imaged pair. The positions of the right LSiC drivers were switched in order to give me an arrangement where the midrange drivers of each LSiC was in the center and both bass drivers were on the outer edges. I had to splice in some additional wire because the midrange driver wires were not long enough to reach the new location.

Hi Raife,

The other day an aquaintance visited my home theater for the first time and commented that he really liked the sound and envelopment of the surrounds (f/x500is on the sides and LC265i in the rear), but he thought the center channel (CS400i) did not timbre match very well with the mains (SDA-1Cs).

Although I can't seem to hear the difference in timbre between the SDA-1Cs and the CS400i, I know that many folks with trained ears have made the same comment. This leads me to consider how I might eventually improve the timbre matching of my center speaker.

Since I'm not very handy with a soldering iron I have been considering a few approaches that don't require speaker modifications.

1. Replace my CS400I with an LSiC
2. Replace the CS400i with a single CRS
3. Replace the CS400i with a pair of CRS speakers without the interconnect

From your comments above it is obvious that you have done a lot of experimentation in this area. In particular, it would appear that your best results were obtained by wiring the SDA drivers of CRS+ in parallel with the stereo driver and using a pair of CRS+s rather than a single speaker. Apparently this arrangement is even superior using two rewired LSiCs

In my situation aesthetics are not a concern since my speakers will be hidden from view behind acoustically transparent fabric. So if I can find suitable CRS+s I think they might be my best bet. To avoid the comb filtering issue that I discussed in an earlier post, it would be possible for me to mount one CRS+ below and the other above the screen. (Please refer to the Front view shown in the concept drawings.) However, I'm concerned that placing a speaker about 18" from the ceiling could create other acoustic problems that might be worse the comb filtering.

Please forgive this rambling posting, but I would value your comments, as well as other Club members, on the pros and cons of the various approaches I have touched on.

Thanks in advance.

Larry

DarqueKnight

Originally posted by Larry Chanin
Although I can't seem to hear the difference in timbre between the SDA-1Cs and the CS400i, I know that many folks with trained ears have made the same comment. This leads me to consider how I might eventually improve the timbre matching of my center speaker.

If you can't hear a difference now, how do you know that changing centers will be worth the trouble? If you are happy with what you have, why change anything?

Originally posted by Larry Chanin
However, I'm concerned that placing a speaker about 18" from the ceiling could create other acoustic problems that might be worse the comb filtering.

Most ceiling mounted speakers sound good provided they are aimed properly. Because sound becomes more localized and directional as you go up in frequency, the ideal arrangement is to have the tweeters of the center as close as possible to the tweeters of the front speakers. You will probably have to experiment a bit to get the correct downward angle of the upper CRS+.

Originally posted by Larry Chanin
In particular, it would appear that your best results were obtained by wiring the SDA drivers of CRS+ in parallel with the stereo driver and using a pair of CRS+s rather than a single speaker. Apparently this arrangement is even superior using two rewired LSiCs

What is better depends on what sounds good to you. Again, I do not see a need to change your current configuration if you are satisfied with the sound.

If you are set on making a change, my preferences would be for the three choices you listed above, but in reverse order (i.e. #3 being the first choice). Isn't all this tweeking fun?:)

RuSsMaN

I'm all for whatever floats anyone's boat, but to use SDA speakers of ANY variety for Centers or Rears is approaching blasphemy in my book.

If your HT system also doubles as your music system, sure, SDA mains, why not. As far as the rest - rears, center(s) etc - Monitor or RTA to get close timbre with the SDA's.

Maybe I'm alone on this one, if so, fine - but seeing as the SDA's (any model) setup in a 2ch config, literally FLOOR most anyome demoing / listening to it, why WASTE it for a friggin center in HT. They are speakers built for 2ch, yeah, read that TWO CHANNEL MUSIC, and they do it SO friggin well - it kills me for anyone to even CONTEMPLATE a pair of CRS for a friggin CENTER channel.

Are you guys shitting me? If you have extra 'SDA' laying around, thats a sign you need to setup another 2ch rig. To buy more SDA for Center/Rear HT purpose? Give me a break. You guys have lost your friggin minds. F HT.

Cheers,
Rooster

HBombToo

Originally posted by RuSsMaN


Are you guys shitting me? If you have extra 'SDA' laying around, thats a sign you need to setup another 2ch rig.

To buy more SDA for Center/Rear HT purpose? Give me a break. You guys have lost your friggin minds. F HT.

Cheers,
Rooster

Nope! no ****... I'm trying to move my collection of outstanding speakers into the room where the multi-channel is.

YES the sda's could bring huge benefit for multi media and I can test it and occupy hours of drinking time.... where is the foul?

I want to measure the sound difference of CRS+ with a mono signal and with my existing cables try to delay 1 side or the other to simulate the effect. GOOOOOOOOd Lord I hope Mr Polk never see's this

twin

Dennis Gardner

Russ,

I agree with you on the SDA's for surrounds. The strengths of the design aren't being utilized.

I have always loved when someone stretches the boundaries of conventional thoughts though.

This has always been the case with this Infinity IRS V setup!

King of Overkill!

Doesn't make SDAs seem all that unreasonable does it?

DG

Larry Chanin

Originally posted by raife1
If you can't hear a difference now, how do you know that changing centers will be worth the trouble? If you are happy with what you have, why change anything?

Hi Raife,

Thanks very much for the prompt response.

You of course are absolutely right, and this would be one of my down-the-road upgrades. After all I would have to find someone willing to part with their CRS+s. However, I believe the ear acquires a taste for less than perfect sound simply because that's all it hears. For example a lot of folks come to like boomy bass because they think that's what it's supposed to sound like. I don't have a trained ear, and I'm thinking it will stay that way unless I get it accustomed to hearing the right sound.

Most ceiling mounted speakers sound good provided they are aimed properly. Because sound becomes more localized and directional as you go up in frequency, the ideal arrangement is to have the tweeters of the center as close as possible to the tweeters of the front speakers. You will probably have to experiment a bit to get the correct downward angle of the upper CRS+.

Excellent point. An other thing I like about vertically stacking the CRS+s is that their combined signals, when properly adjusted, will project an image in the dead center of the screen. Many home theater enthusiasts resort to perforated screens to do this, but it invariably hurts picture quality.

As you can see from the drawing the tweeters of the SDAs currently aren't vertically centered on the screen. Perhaps if I pursued this arrangement it would be advisable to build suitable stands for them.

Thanks again for your advice.

Larry

Larry Chanin

Originally posted by RuSsMaN
I'm all for whatever floats anyone's boat, but to use SDA speakers of ANY variety for Centers or Rears is approaching in my book.

Hi RuSsMaN,

Thanks for your response.

I feel your pain. No insult intended, but as an SDA pureist I'll bet that just the title of this thread "an SDA based HT" set the hair up on the back of your neck.

Seriously, I do understand your point that SDAs are designed for stereo applications. However, because of that I'll have to disagree a little with your point about the rears. I have a Lexicon processor. One of its claims to fame is that it produces true stereo rears, not that decorrelated stuff most "7.1" surround decoders use. As a result I could use CRS+s in the rear with the interconnect cable. However, for my theater I have decided to hide all the speakers from view, this would be impossible to do with CRS+s.

If your HT system also doubles as your music system, sure, SDA mains, why not. As far as the rest - rears, center(s) etc - Monitor or RTA to get close timbre with the SDA's.

With regard to matching the rears, I started a thread that addressed this exact point. Help Matching Surround Back speakers to SDA-1Cs in Home Theater

The concensus was that for my In-Wall situation the LSi series tweeters comes closest to matching the SL2000s. In fact I even got a response from Matt Polk via Ken Swauger on the subject.

Hello Larry,
Here's the response from Matthew Polk:

"Ken -

The SL2000 tweeter was smoother at the top end than both it's
predecessors, the SL1000 and KO10DT. The tweeter in the RCi series would be equally smooth when used in a free standing system such as the RTi's but the in-wall application introduces some roughness in the top end which may not be a good match for the SL2000's in the SDA-1c's. The LCi/LSi is inherently smoother and additional care in the grill design and diffraction considerations makes the LCi in-walls much smoother than the RCi's and a better match to the SL2000's.

-msp"
Regards, Ken

As a result I went with LCi265 with performance enclosures. The LCi series In-Walls have the same tweeters as the LSi series.

Maybe I'm alone on this one, if so, fine - but seeing as the SDA's (any model) setup in a 2ch config, literally FLOOR most anyome demoing / listening to it, why WASTE it for a friggin center in HT. They are speakers built for 2ch, yeah, read that TWO CHANNEL MUSIC, and they do it SO friggin well - it kills me for anyone to even CONTEMPLATE a pair of CRS for a friggin CENTER channel.

Are you guys shitting me? If you have extra 'SDA' laying around, thats a sign you need to setup another 2ch rig. To buy more SDA for Center/Rear HT purpose? Give me a break. You guys have lost your friggin minds. F HT.

Cheers,
Rooster

Hey Russ, please stop shouting and calm down. No blasphemy was intended. However, the fact remains that the CRS+, regardless of their original design intent, are still the best center match for my SDA-1Cs.

Finally, although I don't want to raise your blood pressure any higher, not everyone is a two channel music enthusiast. Some folks like multi-channel music when the sound mixers don't go nuts with the surround channels. As I mentioned SDA might find good use in such a setup if the surrounds are stereo.

Nevertheless I do value your opinion, and just hope we can agree to disagree.

Regards,

Larry

RuSsMaN

Larry, I am and was fine - that's just how I lay it out. Actually, I was hoping you could find a pair of NOS AB-7 In-walls, that used the SL2000.

If you don't see 'F you Larry' at the end, assume all is well.

Cheers,
Russ

Larry Chanin

Originally posted by RuSsMaN
Larry, I am and was fine - that's just how I lay it out. Actually, I was hoping you could find a pair of NOS AB-7 In-walls, that used the SL2000.

Hi Russ,

Interesting information. The LCi265s In-Walls with the performance enclosures are working out fine. I'm not familar with NOS In-walls, but I'd be surprised if they can go as low as the Polks with the enclosures.

If you don't see 'F you Larry' at the end, assume all is well.

Cheers,
Russ

I figured as much, your postings have a directness that leaves little doubt where you're coming from. But it never hurts to be polite, especially to a guy that really knows his stuff.

Regards,

Larry

RuSsMaN

NOS meaning new-old-stock.

The AB 7 was a Polk inwall from the late 80's with the SL2000 and a single 650x midbass.

Man, I don't know JACK compared to some of the guys around here. I just like to listen to music.

Cheers,
Russ

DarqueKnight

Larry,

Forum member Tyrone has a HT setup similar to what you are planning. His rig is in the system showcase and is the 22nd item from the bottom of the list. Tyrone is using a pair of CRS+'s for centers, another pair for surrounds, a single CRS+ for rear center,and SDA 1.2s for fronts. Tyrone's CRS+ centers are located fairly close to the ceiling. At one time, Tyrone was using a pair of SDA 2.3's for surround speakers! You might want to shoot Tyrone a PM to get his insights. He does not visit the forum often, so if he does not respond to a PM, you can PM your email address to me and I will forward it to him.

In one of my previous HT configurations, I used two pairs of SDA 1C's (for fronts and surrounds) and a pair of modified CRS+'s as centers. In terms of cohesive soundfield and timbre matching, it was the best sounding HT rig I had ever put together. I eventually replaced the 1C surrounds with LSi15's. Exact timbre matching in the rear field really wasn't that important to me and the LSi15's were a very, very good match to the 1C fronts I was using at the time and also to the SDA 1.2's that I subsequently replaced the 1C's with.

I think that LSi series speakers sound very similar to SDAs from the midrange up through the treble. When I replaced my dual CRS+ centers with dual LSiC's, the timbre match was very close. The only thing I really miss about having the CRS+ centers is the bass extension they provided. As I stated earlier, I replaced the CRS+ centers for aesthetic reasons rather than sonic reasons. If, in the future, I go to a configuration where I can place the center speakers directly behind the screen (ideal), directly below the screen, or built into the wall above the screen, I would immediately switch back to the CRS+'s.:D

Larry Chanin

Originally posted by RuSsMaN
NOS meaning new-old-stock.

The AB 7 was a Polk inwall from the late 80's with the SL2000 and a single 650x midbass.

Hi Russ,

Duh! Thanks for the clarification.

Larry

Larry Chanin

Originally posted by raife1
Larry,

Forum member Tyrone has a HT setup similar to what you are planning. His rig is in the system showcase and is the 22nd item from the bottom of the list. Tyrone is using a pair of CRS+'s for centers, another pair for surrounds, a single CRS+ for rear center,and SDA 1.2s for fronts. Tyrone's CRS+ centers are located fairly close to the ceiling. At one time, Tyrone was using a pair of SDA 2.3's for surround speakers! You might want to shoot Tyrone a PM to get his insights. He does not visit the forum often, so if he does not respond to a PM, you can PM your email address to me and I will forward it to him.

Hi Raife,

Thanks again for your interest. I remember seeing Tyrone's setup on the McGowan brother's SDA web site. Talk about SDAs!!! I've got a number of other higher priorities in finishing my theater, but I'll probably shoot him a message. Right now I'm trying not to design myself into a corner. My screen wall will have removeable panels so I'll be able to change out my center at some time in the future.

I've got an other question for you. You mentioned that when you wired your SDA drivers in parallel with the stereo drivers the speaker impedance went down to 3 ohms. How did you wire each CRS+ to the center channel amplifier? In series? Or did you use two amps? I've got a Parasound HCA2003 powering my front three channels at about 200 watts per channel.

Thanks.

Larry

DarqueKnight

I used a single stereo amplifier (Adcom GFA-5500) with the speakers connected as in normal stereo. My preamp has two center channel outputs, therefore I did not need to use a splitter.

The Adcom is supposed to be stable into impedances as low as 2 ohms. I did check with both Polk and Adcom before doing this. They both said there should be no problems as long as I did not drive the amp to full power output.

tugboat

Okay, this might not be the best setup, but to my ears, it's incredible!

Front main: 1.2tl
Center: CS350
Surround(side): LS/FX (dipole mode)
Surround(rear): RT800
Sub: PSW650

This is run with the Denon 5803A receiver (for 6 ohm speakers it's 200wpc, and 170 for 8 ohm). The sound is incredible. I know the tweeter matching up front is not perfect, but seems to work nicely. I'm impressed with the depth and width of the soundstage. My neighbors hate me (live in an apartment), but inviting them every now and then to watch a movie seems to calm them.

Larry Chanin

Originally posted by raife1
I used a single stereo amplifier (Adcom GFA-5500) with the speakers connected as in normal stereo. My preamp has two center channel outputs, therefore I did not need to use a splitter.

The Adcom is supposed to be stable into impedances as low as 2 ohms. I did check with both Polk and Adcom before doing this. They both said there should be no problems as long as I did not drive the amp to full power output.

That's a very convenient setup. So you are using both channels of your amp, one per speaker. My Parasound amplifier only has a single channel for the center, so it looks like I would need to buy an other stereo amplifier to do this.

Larry

madmax

Originally posted by RuSsMaN
I'm all for whatever floats anyone's boat, but to use SDA speakers of ANY variety for Centers or Rears is approaching blasphemy in my book.
Cheers,
Rooster

Smoke 'em if you got 'em.
madmax

Larry Chanin

Originally posted by raife1
I used a single stereo amplifier (Adcom GFA-5500) with the speakers connected as in normal stereo. My preamp has two center channel outputs, therefore I did not need to use a splitter.

The Adcom is supposed to be stable into impedances as low as 2 ohms. I did check with both Polk and Adcom before doing this. They both said there should be no problems as long as I did not drive the amp to full power output.

Hi Raife,

I'd like to pursue this dual CRS center approach, but it just occured to me that I only have a single set of speaker cables prewired to my center channel location so I won't be able to run a pair from each channel of a stereo amp to to each speaker.

I use Parasound HCA-1500A amplifiers. These are stereo amps, that can be bridged for mono operation. They are rated at 630 watts RMS when bridged. However, it is not recommended to drive loads less than 8 ohms when bridged.

I assume that the CRS speakers have a nominal impedance of about 6 ohms so if I were to run them in parallel that would over-duty the amp.

Could I run the CRS speakers in series for a total impedance of 12 ohms? Are there any downsides with this approach?

Thanks again.

Larry

DarqueKnight

It wouldn't do any harm, but I do not think you would be happy with the sound quality. In addition to lowering the output power of the amp, the 50% higher impedance may cause some noticeable peaks and nulls in the amp's frequency response. Some amps also have much higher distortion in bridged mode. This can cause a "hardness" and loss of detail in the sound.

I would send an email to Parasound and ask how a bridged HCA 1500A in will perform with a 12 ohm speaker. Specifically ask about frequency response and distortion specifications in bridged mode.

Also, be sure to tell Parasound what type of system you are putting together. If you are going to use another HCA 1500A to power the front speakers, the sound of the stereo HCA 1500A may not closely match the sound of the bridged HCA 1500A, which would defeat the purpose of having timbre matched speakers.