Elucidating AVR Channels vs Total Channels with an Amplifiers

[Fried Chicken]

Hi all

I have a dilemma, and I think the best way to explain it is to give a little bit of background, and describe the predicament I’m faced with. I hope this is the appropriate forum because it is specific to AVR receivers, and less to all the ancillaries of home theater.

Background:
I currently have an extraordinary Yamaha RX-A810. I bought it in a set someone was selling driving 5 polk speakers in a 5.1 configuration (Two RTI A3, a CSI A4, two older gen polk bookshelfs, and a psw111). The whole set together was absolutely excellent, but the cocaine of MOAR was calling. The room I have is 23’ x 17’ with 9’ ceilings.

I got a pair of Paradigm monitor 9 v4’s for my fronts, and upgraded my CSI A4 to a CSI A6. The RTI A3’s are relegated to the front surround, and the older polk bookshelf’s to the rear surround position. I spent a good few days battling the Chernobyl Hot Zone to get the rear surrounds wired through the attic. While I was back there, I also had the foresight to pre-wire for four overhead ceiling speakers.

It’s all quite good, *however*, I think my RX-A810 is at or beyond its power limit. Between the extra speakers, larger speakers, and longer wires, I think it’s overstressed.

Thus my dilemma. To relieve stress and stay within budget, I was considering getting an inexpensive power amplifier for the rear surrounds using the pre-outs of the receiver, then using the extra two-channels to bi-amp the front speakers. This would maximize the receiver, give the (potential) benefit of bi-amping, and be inexpensive. But can the receiver do this? The receiver is advertised as having a max of 7-channels driven, which I assume means the power amplifier, but what if I have an external amplifier?

And then I considered an alternative approach: buy a more powerful amplifier for just the front speakers, and then down the line get a dolby-atmos capable receiver. Then for a 7.2.4 surround setup, I would only need a 9-channel amplified receiver, no?

How does this all tie together? My current receiver has 9 channels of output (2 for zone 2 or height), but it only wants to drive 7 channels. If I do the bi-amp configuration as I’m imagining (with the rear surround being powered by an amplifier), can I still have my 7 channels of surround? The crutchfield guy I spoke with said “sure” and pointed me to an amplifier, btu in my head I’m still going “are you sure”?

I’ve scoured the manual and can’t find any information on the subject. I need an adult. Please help.

 

[lovinthehd]

Not sure what you think you get doing passive bi-amping with an avr but I wouldn't bother myself. Might want to read this https://www.audioholics.com/frequent-questions/the-difference-between-biamping-vs-biwiring

In general if I'm going to buy an amp I'll use it on the L/R/C channels first, let the avr amps handle the surrounds. You might want to use an spl calculator like this to approximate your needs in your room http://myhometheater.homestead.com/splcalculator.html

 

[Fried Chicken]

Not sure what you think you get doing passive bi-amping with an avr but I wouldn't bother myself. Might want to read this https://www.audioholics.com/frequent-questions/the-difference-between-biamping-vs-biwiring

In general if I'm going to buy an amp I'll use it on the L/R/C channels first, let the avr amps handle the surrounds. You might want to use an spl calculator like this to approximate your needs in your room http://myhometheater.homestead.com/splcalculator.html

I don’t like the crossover of the internal floorstanding speaker. I feel it’s wonky.
I also want to use those two extra channels of amplification to help boost more power (or am I misunderstanding something here?).

The SPL meter puts it at 120 dB, but I don’t think that’s right. Why would anyone ever need an amp then, much less a 200 watt/channel amp?

 

[pwrofgrayskull]

7.2.4 requires an 11 channel amp with two sub outputs.

Your amp appears to use the rear surround channels for bi-amping the fronts, likely meaning the RCA pre out for your rear surrounds would just be the copy of the front channel.

IMHO, the best way to lighten the load on your amp and to get the most significant improvement is to get a 2 or 3 channel power amp to run your front L/R (and maybe center). A nice stereo power amp could relay “amp up” your music listening experience. (Pun intended)

Higher efficiency / sensitivity speakers also help (I didn’t look yours up)

 

[Fried Chicken]

7.2.4 requires an 11 channel amp with two sub outputs.

Your amp appears to use the rear surround channels for bi-amping the fronts, likely meaning the RCA pre out for your rear surrounds would just be the copy of the front channel.

IMHO, the best way to lighten the load on your amp and to get the most significant improvement is to get a 2 or 3 channel power amp to run your front L/R (and maybe center). A nice stereo power amp could relay “amp up” your music listening experience. (Pun intended)

Higher efficiency / sensitivity speakers also help (I didn’t look yours up)

Apparently the Paradigm Monitor 9 v4’s are quite sensitive at 94 dB, however I’m not sure that’s accurate. Regardless, I plan on replacing them with RTI A5’s because the paradigm's simply don’t match with the rest of the setup.

Paradigm Monitor Series 9 - speakers Specs

Paradigm Monitor Series 9 - speakers overview and full product specs on CNET.

www.cnet.com

The rest are 89-90dB.

The SPL calculator told me 120 dB, but I just don’t believe that either.

 

[pwrofgrayskull]

I don’t like the crossover of the internal floorstanding speaker. I feel it’s wonky.
I also want to use those two extra channels of amplification to help boost more power (or am I misunderstanding something here?).

The SPL meter puts it at 120 dB, but I don’t think that’s right. Why would anyone ever need an amp then, much less a 200 watt/channel amp?

Unless your speakers are special, you can’t bipass the crossover just by bi-amping the speaker (removing the jumper). You’d have to remove the crossover from the circuit/signal path internal to the speaker which is never recommended. You’re better off selling those speakers and getting something that appeals to you.

 

[lovinthehd]

I don’t like the crossover of the internal floorstanding speaker. I feel it’s wonky.

Not much you can do about that except change speaker or ripping out the passive crossover and doing active bi-amping (the real kind).

I also want to use those two extra channels of amplification to help boost more power (or am I misunderstanding something here?).

Did you read the article I linked? Hopefully you're not thinking it doubles it or something....

The SPL meter puts it at 120 dB, but I don’t think that’s right. Why would anyone ever need an amp then, much less a 200 watt/channel amp?

What spl meter do you have? What weighting/scale is it? 120 is dang loud (THX standard at your listening position would be 85dB average with allowance for 20dB peaks, and 10dB more than that for the LFE channel, so a total reading of 120 for reference level playback of a movie is possible). To gain 3 dB spl you need to double amp power and goes quickly but most avrs are within 1-2 dB of each other generally. 200 wpc would be more a starting point perhaps depending on speaker/use.

 

[pwrofgrayskull]

Apparently the Paradigm Monitor 9 v4’s are quite sensitive at 94 dB, however I’m not sure that’s accurate. Regardless, I plan on replacing them with RTI A5’s because the paradigm's simply don’t match with the rest of the setup.

Paradigm Monitor Series 9 - speakers Specs

Paradigm Monitor Series 9 - speakers overview and full product specs on CNET.

www.cnet.com

The rest are 89-90dB.

The SPL calculator told me 120 dB, but I just don’t believe that either.

Not too shabby!

Remember, your amp’s spec is:

• 100 watts per channel into 8 ohms (20-20,000 Hz) at 0.09% THD, with 2 channels driven

So at high volume in a full surround setup, that amp will struggle to push those beauties. Then again, you could save your ears and keep your neighbors happy by not cranking the volume ;P

 

[Fried Chicken]

I don’t like the crossover of the internal floorstanding speaker. I feel it’s wonky.

Not much you can do about that except change speaker or ripping out the passive crossover and doing active bi-amping (the real kind).

I also want to use those two extra channels of amplification to help boost more power (or am I misunderstanding something here?).

Did you read the article I linked? Hopefully you're not thinking it doubles it or something....

The SPL meter puts it at 120 dB, but I don’t think that’s right. Why would anyone ever need an amp then, much less a 200 watt/channel amp?

What spl meter do you have? What weighting/scale is it? 120 is dang loud (THX standard at your listening position would be 85dB average with allowance for 20dB peaks, and 10dB more than that for the LFE channel, so a total reading of 120 for reference level playback of a movie is possible). To gain 3 dB spl you need to double amp power and goes quickly but most avrs are within 1-2 dB of each other generally. 200 wpc would be more a starting point perhaps depending on speaker/use.

Sorry that was a typo, the SPL calculator loveinthehd recommended! I don’t have an SPL meter. Like I said, I don’t believe the calculator.

I’m also not looking to double the output by bi-amping, however I do expect to see a bit of a boost and/or more clarity. The boost by removing two speakers from the receiver amp, and the clarity from the benefits of bi-amping.

Is it possible to bi-amp an rx-a810 and then use the pre-outs and a separate amplifier for the surround back speakers? The reason I was considering this is because I might be able to get a low power (say 60w/channel) relatively cheaply.

Otherwise, and I think for future-proofing sake, it might be wise to plop $300 on an old yamaha amplifier for the two front channels. Then when I decide to get atmos I could get an RX-A2050 (whenever those become cheap - I’m poor).

 

[lovinthehd]

It's simply math being done for you, just audio science at work. Your speakers may not be quite as sensitive as their rating in real life so you can use a 2-3 dB lower figure and maybe allow for another 3dB of headroom for power.....and you don't want to drive the avr at full power all the time either. I imagine you can calibrate the avr with YPAO and let us know what your usual listening levels are on the relative scale? Or do you plan on listening at reference level a lot? Hard to know unless you provide some specifics.

I still don't understand what you think passive bi-amping will do particularly other than use more wire and the terminals on the speakers...it's mostly about marketing as both the avr having this "feature" as well as the speakers with additional terminals....more about keeping up with the marketing joneses. As the conclusion of the linked article mentions, if you want more power to the speakers then get a more capable amp.

Using a used amp/receiver is always a good way to go. Pro amps another to save some money.

 

[Fried Chicken]

It's simply math being done for you, just audio science at work. Your speakers may not be quite as sensitive as their rating in real life so you can use a 2-3 dB lower figure and maybe allow for another 3dB of headroom for power.....and you don't want to drive the avr at full power all the time either. I imagine you can calibrate the avr with YPAO and let us know what your usual listening levels are on the relative scale? Or do you plan on listening at reference level a lot? Hard to know unless you provide some specifics.

I still don't understand what you think passive bi-amping will do particularly other than use more wire and the terminals on the speakers...it's mostly about marketing as both the avr having this "feature" as well as the speakers with additional terminals....more about keeping up with the marketing joneses. As the conclusion of the linked article mentions, if you want more power to the speakers then get a more capable amp.

Using a used amp/receiver is always a good way to go. Pro amps another to save some money.

Didn't the founder of this site advocate to yamaha to include bi-amping in their receivers with the justification being: the amplifiers are there, use them?

I did use YPAO and it came out to almost all 0, which is great. I just run pure direct.

I do listen to quite loud a lot. Actually I managed to overheat the receiver to the point of it shutting off. I moved my fan to the top of the receiver after that (I have a small fan plugged into the USB port). I've also noticed some distortion I guess is the right word. I'm not sure if that's a function of power output or the digital signal processing (When not running in pure direct).

 

[lovinthehd]

Not heard that Gene did that, no. I'd just use them for another set of speakers rather than passive bi-amping. YMMV.

You mean speaker trim levels came out to 0? Was more curious about the reading on the volume scale (using the reference scale where "0" on the volume is reference level).

You indeed may be a candidate for a good power amp in any case.

 

[ryanosaur]

I’m also not looking to double the output by bi-amping, however I do expect to see a bit of a boost and/or more clarity. The boost by removing two speakers from the receiver amp, and the clarity from the benefits of bi-amping.

There has never been, as best I can tell, any measured benefit from passive bi-amping. Never seen a scientific article that spells out anything remotely worthwhile to come from it. Hearsay and Conjecture, on the other hand... plenty of that!
In fact, I would argue that using multiple channels from an AVR only robs available power from the Amp stage.
Though it would still not result in any audibe benefit, you would be better served using multiple external amps for what you are discussing...
But frankly, that would still be a waste. that's why it gets called Buy-Amping or Buy-Wiring.
(Or of course, Single Amping from the AVR... this is really just fine.)

In all honesty, I looked hard at this myself. It really just isn't worth it. If you feel you need or want an Amp, then cool. Whether you really need it or not. Still Cool.
Consider that Polk speakers are usualy hard to drive, in that they present a difficult load with a sharp phase angle at low impedance. You should Amp, single channel only with an Amp that is stable to 4 or even 2 Ohms. But unless you are experincing problems with you speakers and the AVR in single-amp usage, you could save some money...
...And put it toward better speakers!

 

[everettT]

I don’t like the crossover of the internal floorstanding speaker. I feel it’s wonky.
I also want to use those two extra channels of amplification to help boost more power (or am I misunderstanding something here?).

The SPL meter puts it at 120 dB, but I don’t think that’s right. Why would anyone ever need an amp then, much less a 200 watt/channel amp?

I'd make sure you get an amp that can be very easily driven as that unit dosent output much on the preouts before clipping, fyi.

 

[Fried Chicken]

Not heard that Gene did that, no. I'd just use them for another set of speakers rather than passive bi-amping. YMMV.

You mean speaker trim levels came out to 0? Was more curious about the reading on the volume scale (using the reference scale where "0" on the volume is reference level).

You indeed may be a candidate for a good power amp in any case.

I think he mentioned it when talking about the yamaha line, and he spoke with yamaha telling them what he wanted to see ("most receivers have 7 channels but only use 2, so use those extra channels for bi-amping"). It's in some video somewhere, I might find it.

What do you mean by speaker trim levels or what? YPAO put around 0dB for all the speakers. Or do you mean when the amp turned itself off? Idk, it was loud. It also depends on the source, some stuff is super loud at -10dB others at 0. I think uncompressed stuff is less loud, no idea why.

I think before I get an Amp I'll sell the paradigm's and get the RTI A5's.

 

[lovinthehd]

I think he mentioned it when talking about the yamaha line, and he spoke with yamaha telling them what he wanted to see ("most receivers have 7 channels but only use 2, so use those extra channels for bi-amping"). It's in some video somewhere, I might find it.

What do you mean by speaker trim levels or what? YPAO put around 0dB for all the speakers. Or do you mean when the amp turned itself off? Idk, it was loud. It also depends on the source, some stuff is super loud at -10dB others at 0. I think uncompressed stuff is less loud, no idea why.

I think before I get an Amp I'll sell the paradigm's and get the RTI A5's.

When you said YPAO set everything to zero, that sounds like speaker trim levels. For volume, yes, what is indicated during your usual listening or when it goes into protection. Are you talking about music or movies at this level? Using multi-ch stereo mode perhaps? The standard for reference volume is only for the movies that utilize the standard, music is all over the place.

 

[Fried Chicken]

When you said YPAO set everything to zero, that sounds like speaker trim levels. For volume, yes, what is indicated during your usual listening or when it goes into protection. Are you talking about music or movies at this level? Using multi-ch stereo mode perhaps? The standard for reference volume is only for the movies that utilize the standard, music is all over the place.

It was 7 channel stereo. It wasn't a specific level, it's temperature based. The receiver was quite hot lol.

Now I put the fan on top.

truck me; im dying of cabin fever.

 

[lovinthehd]

It was 7 channel stereo. It wasn't a specific level, it's temperature based. The receiver was quite hot lol.

Now I put the fan on top.

truck me; im dying of cabin fever.

The 7ch stereo mode is more stressful to the amp than a surround mode. Personally don't use the all ch stereo modes except maybe during a party. Still, volume levels and type of content are somewhat indicative of how hard you're working the amp....and heat is one result Fan on top of an avr is often useful.

 

[Fried Chicken]

The 7ch stereo mode is more stressful to the amp than a surround mode. Personally don't use the all ch stereo modes except maybe during a party. Still, volume levels and type of content are somewhat indicative of how hard you're working the amp....and heat is one result Fan on top of an avr is often useful.

I’m still stuck with my original dilemma. Can I get an amp to drive the two rear surrounds and then bi-amp the fronts, or would this exceed the 7-channel max of the amplifier?

 

[lovinthehd]

I’m still stuck with my original dilemma. Can I get an amp to drive the two rear surrounds and then bi-amp the fronts, or would this exceed the 7-channel max of the amplifier?

Page 19 of your manual indicates if you want to use the bi-amp feature then you give up the use of the rear surrounds....which makes sense since it's only got 7 channels of processing and after all the amp assign mode to biamp is called "5ch biamp". If you did hook up an amp to the rear surrounds you'd just get a full range L/R signal like the designated bi-amp channels get.