Wiring Multiple Surrounds per Channel

[Phantomguy]

Does anyone have first hand experience with setting up multi-speaker per channel for Surrounds?
I am setting up 7.1 +Presence in a 13’x 22’room using for SPKR SYSTEM A 3x Jensen EHT-8 130W 6 ohm in walls for front stage + 2 EHT-6 110w 6 ohm for Presence speakers (Yamaha RX-V2600 AVR), 2 home made subs, and 2 EHT-4 110w x 6 ohm 40 degree- angled drivers in wall or ceiling (not yet sure) for REAR surrounds. (SYSTEM B: is my old pair of 5spkr x 4way Sansui SP1500 for stereo listening).

Here’s the 7.1 problem area – I have 3 rows of seating so I have been trying to emulate the “multiple side” speakers in commercial theaters so that every row has the correct positioned (side) surrounds (i.e. before I came to know that comm Theatres us 10.2 and have all active (amplified) speakers). So I am trying to place 3 pairs of Surrounds along each side wall at 90 -110 degrees to each row. So do I wire –
• 3x PARALLEL, or
• 3 x SERIES, or
• 2x SERIES + 1 x PARALLEL, or
• 2 x PARALLEL + 1 x SERIES, or
• Use an Impedance Compensation device of some sort (and what should/does that present as an impedance value to the surround channels of the AVR?)

See I don’t want to cause EQ issues for the YPAO system, or degrade sound quality, or affect the “relative” volumes of SL and SR compared to the other channels for the listeners in each of the rows.

Thoughts thus far: My first thought was to maintain 6 ohm load/surround-channel to be seen by the AVR so I don’t introduce quality/balance or danger problems to the AVR. To do this I can’t just wire as 3in Para = 2 ohm, 3 in Ser =18ohm, 2 Para + 1 Ser = 9 ohm, and 2 Ser + 1 Para = 9 ohm (Right???). So I’ve hunted for a “black box” only end up buying on recommendation (?) a no-brand one (1pr -> 4 pr) from Radio Shack/Tandy that was supposed to use combinations of series and parallel (?????) to maintain the impedance seen by the AVR at the same value as “the lowest impedance speaker in the array”. BUT it does not do that. I hooked them up and made measurements –
• 2 SPEAKERS-
o Switch 1 +2 = 6 -> 12ohm (obviously just series);
o Switch 3+4 = same (series);
o either (1 or 2) + either (3 or 4) = <3ohm (seems like just parallel); and
• 3 SPEAKERS –
o any pair of 1 + 2, or 3 +4 with ONE of the other two = 4ohm (not sure why ?????).
• 4 SPEAKERS`-
o of course as 4 speakers it gave the original 6 ohm as the be expected by 2 parallel pairs then each air in series with the other parallel pair.  But if I use 4 (side) surround speakers per channel the only space for placement of the 4th pair will be FORWARD of Row 1 and then cause as shift of the surrounds track well FORWARD for each Row. Not to mention the price of another pair of speakers - money thrown away.

I have seen webpages with products like Phoenix SAM100 and DAYTON SSC-5 SPEAKER SWITCHING CENTER but none of the sites gives specific information as to what methods are used or what impedance values you can expect with various number of speakers (and no “contact us“ links obvious).

Key Discussion Point: I am now starting to question the merits trying to show the AVR 6 ohm just to match the other channels. The first audio-shop guy said “hook the three up in series (18ohm???) so that even though the volume of each will be lower , the SUM of the output from the 3 speaker array will be the same as the intended original for ONE SPEAKER (I’m not even sure that is right??).

I argued that may(?) be mathematically correct but (a) most of the volume “heard” in any row would be from the near (90-110 degree adjacent speaker and much less from the other two more “distant” speakers, and (b) the reduced volume levels surely would also drop the quality based on the dynamics of the speaker (sensitivity rating etc??). A second audio-shop guy told me “then just hook them up all in parallel: that way each speaker will output the intended volume level as though it were the only one alone. (Yes but what about risk to the AVR at ~ 2 ohm, and its “confusion”, and what do it set in the menu to for spkr impedance where 5 channels are 6 ohm and 2 are 2 ohm?)

So in conclusion I’m more uncertain that ever. Do any of you guys or gals have first hand experience/knowledge as to what is the best way for me to proceed from here and get it “right” first time? REMEMBER please that with in-wall, in-ceilings I don’t have the luxury or placing them in multiple locations with multiple hookups to repeated test out all the iterations UNLESS I WANT SWISS CHEESE for my final walls and ceilings 

P.S. Sorry for long post but after weeks of getting nowhere I’m now highly frustrated.

 

[xboxweasel]

Why not get seperate amps for each speaker and split the preouts as you need them.
IE:
3 amps for the right surround speakers
3 amps for the left surround speakers
1 amp for the front left speaker
1 amp for the front right speaker
1 amp for the centre speaker
2 amps for the surround back speakers

Then you don't have to worry about parallel and series connections. And their resulting impedance. Or putting anything other than 8 ohm loads on the receivers build in amps. The only problem is you could not adjust the gain to each speaker seperately. You could only adjust the gain for the one preout.

 

[Sheep]

Why not get seperate amps for each speaker and split the preouts as you need them.
IE:
3 amps for the right surround speakers
3 amps for the left surround speakers
1 amp for the front left speaker
1 amp for the front right speaker
1 amp for the centre speaker
2 amps for the surround back speakers

Then you don't have to worry about parallel and series connections. And their resulting impedance. Or putting anything other than 8 ohm loads on the receivers build in amps. The only problem is you could not adjust the gain to each speaker seperately. You could only adjust the gain for the one preout.

You realise you just told him to BUY 11 amps? You can get 2 or 4 channel amps. Splitting the signal should work.

SheepStar

 

[jcPanny]

Speaker configuration

While it may look cool to have 3 speakers on each side, you may get similar or better performance from a multipole surround speaker that is forgiving with placement such as the Axiom QS8's. This speakers uses 2 woofers and 2 tweeters to create a diverse sound field so you might be able to get away with one (or two pairs) in the surround and surround back locations. In comparision, dipoles require more critical placement. If want 3 pairs in each location then go with direct radiating speakers.

Also keep in mind that your Yamaha will run surround back (7.1) OR 5.1 + presence speakers but not both at once.

For something this sophisticated, you should also consider enlisting the help of a professional. Also, the inwall/inceiling speakers and impedence matching boxes are major performance compromises for a large HT such as yours.

 

[Phantomguy]

You realise you just told him to BUY 11 amps? You can get 2 or 4 channel amps. Splitting the signal should work.

SheepStar

Guys, I already have the Yammy and the speakers and the budget is nearing its limit with still more things to finish, so I need "reasonably" economical solutions. 11 amps would be expensive...and wouldn't they me a nitemere to EQ manually ... I had hoped to use the Yammies inbuilt YPAO mic positioned in 1st row, then 2nd, then 3rd to set and test the other seating positions for best "average" .. or maybe the Yammie will save mulit- YPAO setting for recalling when different numbers of audience rows? (havent got it hooked up after 5 months of ownership yet )

As for extra 2 channel/4 channel amps, I have left over my old 2 channel/4 spkr (A+B) Sansui (from 70s) and a low end KODA 5.1 (from 2001). Would these do? Or would they degrade the yammie sound quality? and How would I set them up? Would I preout the L and R surround channels and input them to the (what inputs?) on the 2 or 4? And would that still aow me to use the Yammie YPAO system (i.e does the YPAO work on adjusting preo-outs OR main amps?)

Question again: How do others handle surrounds for multiple rows of seating? I wasn't doing this to "look cool".

 

[Phantomguy]

While it may look cool to have 3 speakers on each side,

Not doing this to look cool .. just wanted each row to get proper (side) surround effect.

you may get similar or better performance from a multipole surround speaker that is forgiving with placement such as the Axiom QS8's. This speakers uses 2 woofers and 2 tweeters to create a diverse sound field

Yes but I already have all the in-walls/ceilings for this room as Zone 1 and the extra ones also for Zone 2 (Bedroom 1)and 3 (Party Room). Also I had to do Inwall/ceilng for surrounds at least for WAF.

so you might be able to get away with one (or two pairs) in the surround and surround back locations.

Even if I was to buy these at EXTRA cost .. they cannot be positioned (LOW) where dipoles should go because there is a large (curtained) sliding door way (and fixed panel glass) all along one side of the rows, but inwall will go above door head and point down (as they have 40degree angled drivers) or in the ceiling and point across to seating. And 2 pairs of dipoles would put me back into the parallel/series arguement again!!

In comparision, dipoles require more critical placement. If want 3 pairs in each location then go with direct radiating speakers.

Yep but I guess I'm sorta stuck with them for positioning and cost reasons. BUT the problem of wiring 3 directs still is unanswered?

Also keep in mind that your Yamaha will run surround back (7.1) OR 5.1 + presence speakers but not both at once.

I have come to know that limitation, however I can one button switch from one mode to the other depending on the track/movie playing thanks.

For something this sophisticated, you should also consider enlisting the help of a professional.

All the professionals I have spoken to in my area have different ideas and theories and are not convincing other than the 30 year veteran guy who told me they do this in commercial theatres with 10.2 system + active speakers all around !

Also, the inwall/inceiling speakers and impedence matching boxes are major performance compromises for a large HT such as yours.

Oh oh. I thought other than lack of bass response (no enclosures) the performance would be fine with these Jensen EHT series. And as with those (tiny) Bose speakers they rely heavily on the sub for bass. Also I know that some installers "nog" between studs/ceiling joists + fill with accoustic material to improve the bass. Also I made up a box calculated for down to 80Hz and tested it over one of these in an inceiling mock ups and the bass improved out of site.

But as for impedance matching boxes: Do they detract from the performance/quality? How is that? And I have been thinking today that isn't there some way to parallel 2 of the surrounds, then parallel the other one with a "dummy" 6ohm coil/ no driver (all these speakers are 6 ohm not 8) and then series the 2 parallel sets to get back to 6 ohms presented to the amp in the AVR? And would that mean that each of the 3 receivers only outputs 1/3 (or maybe even 1/4 of the volume output at that channel and what would that mean to the listened in any one row with one spkr adjacent and 2 others 6' further away and pointing to other rows?

 

[AVRat]

Wired in series would be the correct method for equal output of each speaker. My preference would also be to use only 2 per side. You could also wire one of the two out of phase to get a dipole affect. Even with only one, you’ll get good surround effects in your space.

 

[Buckeye_Nut]

You realise you just told him to BUY 11 amps? You can get 2 or 4 channel amps. Splitting the signal should work.

SheepStar

Yep, either that, or purchase a single 9.1 receiver and use two surrounds per side.

Using a single 7.1 receiver and plugging multiple sets of speakers to the same posts is a big no-no.

 

[Phantomguy]

Wired in series would be the correct method for equal output of each speaker. My preference would also be to use only 2 per side. You could also wire one of the two out of phase to get a dipole affect. Even with only one, you’ll get good surround effects in your space.

Thx AVRat. But wouldnt series up the impedence to 12 ohm (6+6) and therefore drop the total ouput from the AMP on each surround channel to 50% and then that 50% split over 2 speakers so that the result is 25% of the dBs that would otherwise be occuring at one speaker (if 1 spkr/channel)? And wouldnt that sound feeble? (And worse for 3, as 18 ohm: 1/3 dbs shared 3 ways-> 1/9 of db of equivalent 1 spkr at 6ohms?)

Was thinking that -
1) some "black box" presenting 6 ohm total (if poss) would at least give same 100% of dB for AVR 's Volume setting for each surround channel, then split 1/3 each if dbs over 3 speakers, OR
2) if "box" not available then parallel 2 (=3ohm) and parallel 1 to some "dummy" 6ohm load (no drivers - not sure how to do?) (again = 3ohm) then series each set to get back to 6 ohm total load on amp, so surround channels get 100% of db for that setting, then splits 1/3 each (yes??) over 3 speakers; OR
3) Some variable impedance device/splitter (if one exists or could be made) to wire 3 spkr/channel and to drop overall impedance to say about 4 ohm (need to experiment with it) - still safe for AVR - so that dbs on each surround channel are up to about 150% (compared to other channels) then when they split 3 ways to about 50% each - and since each seating row has one "near" surround and 2 "distant" surrounds (5- 10' away) the effect on listeners ear may approximate 100% of intended db for that channel. Make any sense????

The "cheap" Radio Shack/Tandy speaker switch I got on trial the other day (and have only mocked it up for ohm measurements so far) seems when 3 speakers (of a total of 4 max) are connected gives about 4 ohms (no idea why?? and my meter is not accurate at these low ohms and has small zero error). Maybe its worth a try despite it appearing to be simply: 1 +2 = series, 3+4 = seriesl, and set (1+2) paralleled with set (3+4) - so if using just 2 spkrs (either 1+2, or 3 +4) series at 12ohm, and full set of 4 = 6ohm.

Yours thoughts on these options?

 

[Phantomguy]

Yep, either that, or purchase a single 9.1 receiver and use two surrounds per side.

Using a single 7.1 receiver and plugging multiple sets of speakers to the same posts is a big no-no.

Thx Buck. Would be great but I have already bought the 7.1 RX-V2600 4 1/2 months ago and is NOT returnable (dispite not yet hooking it up). Why is this "a big no-no" if the impedance can be "adjusted" a little (somehow) to get a say about 130% - 150% of the dB (say at 60% or less volume setting) sent to each (side) surround channel which then on the spkr side of some "black box" dissipates over 3 x 6 ohm spkrs as 45 -50% each share of the total dBs, so that each row listener gets about 50% loudness from his/her "near" surround spkr and about 25% for each "distant" surround spkr? Buck, do you get the idea I'm trying to achieve by some variable impedance device? Anyone know of any?

 

[jcPanny]

Impedence matching

Lets say you are able to get the impedence matching box in place. It will effectively "divide the power" so that your receiver will deliver 30-35 Watts max to each 3 speakers instead of 90-100 Watts max to a single speaker.
Impedence matching with 30 Watts is fine for background speakers in a whole house system but you will probably want more power for a dedicated HT room.

 

[Buckeye_Nut]

What you are talking about is just not something I would do. Im sure you can jerryrig something to make it work, but it's not the ideal situation. The 2600 is a great receiver and all, but it's not designed for that purpose. To add 2 pairs of surrounds, I would add extra power