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Posted By: LRA two amps? - 06/18/07 01:05 PM
Hi, please forgive my ignorance but I have a question. I have a pair of M22ti at the front and will soon own a pair of QS8. I was wondering if I would see a difference by hooking them to 2 separates amps instead of one. I have two yamaha htr-5960. I would plug my inputs in the first amp and take the pre-amp of the rear and connect them to the second amp.

I don't know if it makes any sense or if I would notice a difference (and I don't really have time to test it since I moved into a new home last week).

my room is ~ 16x12
Posted By: Mojo Re: two amps? - 06/18/07 01:18 PM
You won't notice any difference.
Posted By: LRA Re: two amps? - 06/18/07 01:58 PM
great!! is there only a difference when using bigger loud-speakers?
Posted By: Mojo Re: two amps? - 06/18/07 04:53 PM
It's only a concern when you don't have enough power from a single receiver. Given your room size and receiver model, you have more than enough power.
Posted By: SirQuack Re: two amps? - 06/18/07 05:50 PM
Probably depends on who you ask Luc. People that are "seperates" believers will still prefer them over an integrated design with everything crammed into one box, even in rooms your size.
Posted By: Wid Re: two amps? - 06/18/07 08:51 PM
Quote:

It's only a concern when you don't have enough power from a single receiver. Given your room size and receiver model, you have more than enough power.




How can you make such a statement not knowing what the listening habits of the OP are?
Posted By: Mojo Re: two amps? - 06/18/07 09:36 PM
What's OP?
Posted By: Wid Re: two amps? - 06/18/07 09:41 PM

Original poster.
Posted By: Mojo Re: two amps? - 06/18/07 10:18 PM
Quote:

How can you make such a statement not knowing what the listening habits of the OP are?




I'm assuming the poster is not hard of hearing and that the room is quiet (50dB of ambient noise or better).

One M22 requires 1 Watt to produce 93dB at 3 feet. If the poster sits 9 feet away from the M22s, 1 Watt will result in 84dB from a single M22 or 87dB from two M22s. Given that it's a 100W amp, this will give the poster more than 18dB of headroom. And this doesn't count all of the other channels which could result in even more SPL.

I'm in a room that is about 2.5 times the volume posted and my 90W amp is more than enough even when I listen to classical which is quite dynamic.
Posted By: Wid Re: two amps? - 06/18/07 10:23 PM
Assuming is never a good thing.

Honestly it has been noted before the mathmatics might look good on paper but not always the case in practical terms. Ian noted this in the recent thread about the new Axiom amp.
Posted By: SirQuack Re: two amps? - 06/19/07 12:04 AM

Posted By: pmbuko Re: two amps? - 06/19/07 01:16 AM
Quote:

mathmatics might look good on paper



I always preferred math on the computer screen.

For example, this equation would be quite hard to graph by hand:



But giving it to the computer will quickly give you a pleasing result:


Posted By: Ken.C Re: two amps? - 06/19/07 01:18 AM
If you're 13.
Posted By: CV Re: two amps? - 06/19/07 01:21 AM
That can't be the full equation.
Posted By: pmbuko Re: two amps? - 06/19/07 01:28 AM
ahtah
Posted By: JohnK Re: two amps? - 06/19/07 01:38 AM
Luc, your post is a bit unclear and perhaps has led to a misunderstanding in the earlier replies of what you're proposing. You say that you have two 5960s and you seem to be indicating that you want to connect one to the other(not buy a separate amplifier). If this is what you have in mind, then no, this can't be done with the two 5960s since the second one doesn't have a direct input to its amplifier section, and even if it did you can't run two amplifiers in tandem one after the other and add their power together.
Posted By: Mojo Re: two amps? - 06/19/07 01:59 AM

Math aside, practical experience tells me that one receiver capable of 100W/channelx7 is enough for such a small room.
Posted By: Wid Re: two amps? - 06/19/07 02:01 AM

And I have shut down a 300 watt amp in a room not much bigger. I guess we will have to agree to disagree.
Posted By: Mojo Re: two amps? - 06/19/07 02:37 AM
Was it "loud"? I'm asking because the 300W amp may not have been putting out 300W.
Posted By: SirQuack Re: two amps? - 06/19/07 02:47 AM
Knowing Rick, I'm sure everyone on Route 66 was running for cover. Joking aside, he has been around amps for a long time, so I never have reason to doubt him.
Posted By: LRA Re: two amps? - 06/19/07 03:14 AM
Quote:

Luc, your post is a bit unclear and perhaps has led to a misunderstanding in the earlier replies of what you're proposing. You say that you have two 5960s and you seem to be indicating that you want to connect one to the other(not buy a separate amplifier). If this is what you have in mind, then no, this can't be done with the two 5960s since the second one doesn't have a direct input to its amplifier section, and even if it did you can't run two amplifiers in tandem one after the other and add their power together.




sorry for the confusion but you got it right. Since I got a good deal on the yamaha receivers I wanted to know if it was possible to chain the two receivers together instead of buying a seperate amp (which is expansive). I thought we could plug the pre-amp outputs (rear speakers )from the first amp into the multi-channel inputs of the second amp (for the rear speakers).


Posted By: JohnK Re: two amps? - 06/19/07 03:25 AM
Yeah Luc, that's what I suspected. But on the question of more power capacity, unless you're exceeding the capacity of your 5960 now(possible but unlikely)spending money on a separate amplifier would be just a waste of money. There's no magic in separate amplifiers and unused capacity is simply that: unused.
Posted By: Mojo Re: two amps? - 06/19/07 03:27 AM
There's another angle that we have to consider.

The SPL out of speakers doesn't climb indefinitely. Just because the M80s are rated to 400W, that doesn't mean they don't saturate from an SPL stand-point well below 400W. All the power that goes into them after saturation simply gets converted to heat in the voice coil and filter network. And the room saturates as well. So I don't understand what the "extra" power buys anyone?

And the other question is what does that 400W really mean? I bet I can easily put 400W of complex power into the M80 with my cheap Denon that is rated 90W/channel. At 50Hz (the frequency at which the M80 experiences its impedance minimum), my Denon need only source about 7.5 Amps (real + reactive) which I'm sure it can do. Now as to what it sounds like at that level is an entirely different matter.

I think I'll try this tomorrow to see what happens.
Posted By: Mojo Re: two amps? - 06/19/07 03:30 AM
Luc,

You can't chain amps the way you were thinking. You can hook them up to separate speakers but like Johnk and I have said, you don't need to for your situation.
Posted By: LRA Re: two amps? - 06/19/07 03:44 AM
I'm not using all the power of my receiver. I rarely crank the volume over 1/3.
Posted By: Mojo Re: two amps? - 06/19/07 03:47 AM
There you go. Take the other Yammi back or use it in another room.

I use less than a watt on average for music and a few watts for movies.
Posted By: jakeman Re: two amps? - 06/19/07 10:51 AM
Quote:

sorry for the confusion but you got it right. Since I got a good deal on the yamaha receivers I wanted to know if it was possible to chain the two receivers together instead of buying a seperate amp (which is expansive). I thought we could plug the pre-amp outputs (rear speakers )from the first amp into the multi-channel inputs of the second amp (for the rear speakers).







What you are suggesting is feasible Luc and a good use of both receivers now that you have them. I have done the same setup on several occasions using combinations of amps and receivers for different speakers to free up amp headroom. Your instincts are correct in wanting to keep more power on reserve for the speakers. The net result will be greater dynamic range with less distortion during loud passages and transients and less chance for clipping.

Chaining two receivers is not as good as having a second separate amplifier because you will be running the surround signal through a similar circuit twice. However, depending on how well Yamaha designs its analog circuit it likely will not sound much different.

A better alternative to consider is to run two digital outputs from your player, one to each receiver and hook the mains to one and the centre/surrounds to the other. This configuration also allows more flexibilty with bass management through setting different crossover points among the different speaker groups. It also means you don't have to turn on both receivers if you just want to listen to stereo mains. And though I am not a fan of auto-equalization, it may also help with setting equalization, YPAO, in the Yammies. You should still run the analog connections for DVD-A sources.
Posted By: LRA Re: two amps? - 06/19/07 10:55 AM
Quote:

There you go. Take the other Yammi back or use it in another room.

I use less than a watt on average for music and a few watts for movies.




I will keep them, all three. I have two HT rooms (one yamaha in each room) and I had a great deal at FutureShop for a brand new Pionner AVR for my computer @150$ CDN (it's a model from last year).


Posted By: Ken.C Re: two amps? - 06/19/07 04:10 PM
OK, maybe I'm missing something, but wouldn't the only effect be to use the (identical) amps in the other Yamaha instead of the (identical) amps in the first Yamaha? That doesn't get you anywhere.
Posted By: jakeman Re: two amps? - 06/19/07 04:28 PM
Assuming he has wired them properly, if he uses a Yamaha receiver-amp with one set of speakers and another identical receiver-amp with the other set, he will improve the systems sonic qualiies compared to just using one amp for all speakers. He will have created more headroom with more power on reserve. That typically means improved dynamic range and less distortion especially in transients.
Two amps are sharing the burden of all the speaker load instead of one.
Posted By: Ken.C Re: two amps? - 06/19/07 04:35 PM
Riiiight. So we're talking using one for the fronts, and one for the rears?

Following that logic, my H/K sounds better than someone else running 7.1, because I'm only using it for 5.1?

Sorry, but I'm dubious that taking the load of a few speakers off of a receiver is going to audibly improve the sound.

Ah, the famous transients. Can someone explain what transients are?

EDIT: A further thought (that will anger people, heh): If you're playing it loud enough that you're causing the receiver to distort, you should be using an external amp, anyway. I would wager that just taking 2 speakers off of the thing will not decrease distortion by any significant amount.
Posted By: jakeman Re: two amps? - 06/19/07 04:55 PM
The benefit of multiple amps depends on how much is power is demanded by the speakers and how loud you play them. Its easy to clip amps momentarily during loud passages. While not as dramatic an effect, there was a time when small subs were also powered directly by HT receivers. Now most subs come with their own amps which take the load off the main receiver-amp when you cross to the sub amp. In effect directing a separate amp to the surrounds accomplishes the same thing.

I'm not suggesting anyone go off and buy an identical receiver, but seeing how he has one it makes sense to put it to good use. I know some people who have three amps going: one for the centre, another for mains and a third for surrounds. With good quality speakers the difference is audible, especially if you play movie soundtracks loud like I do.
Posted By: Mojo Re: two amps? - 06/19/07 07:58 PM
He has a 1500 cubic foot room (I'm assuming an 8 foor ceiling).
Posted By: Wid Re: two amps? - 06/19/07 09:15 PM
Quote:

Was it "loud"? I'm asking because the 300W amp may not have been putting out 300W.




Yes it was real freakin loud, just how I like it at times . The amp was a Kenwood Basic M2A. I ended up giving it to a friend of mine when I bought the Rotel.
Posted By: LRA Re: two amps? - 06/20/07 02:16 AM
Quote:

He has a 1500 cubic foot room (I'm assuming an 8 foor ceiling).




I like it loud but my girlfriend don't! I never noticed any clipping but I'm around -24db to -20db when listening to a movie and ~ -34db for tv
Posted By: Mojo Re: two amps? - 06/20/07 02:22 AM
Wow. That looks like a monster.
Posted By: Wid Re: two amps? - 06/20/07 08:56 PM

It was a good amp, very powerful. It is still running to this day. The M2a would be a good amp to pick up used if it can be found for a few hundred bucks.
Posted By: Ken.C Re: two amps? - 06/20/07 09:03 PM
Found one.

Sadly, I have no room for it in my cabinet. Maybe when Axiom releases its 2 channel amps...
Posted By: Wid Re: two amps? - 06/20/07 09:08 PM

To bad, I kicked myself in the ars a few times for letting mine go.
Posted By: Ken.C Re: two amps? - 06/20/07 09:08 PM
It's pretty cheap.... of course, there's 5 days left on it.
Posted By: Wid Re: two amps? - 06/20/07 09:22 PM
I saw it too, I don't need an amp at this time but if someone (Ken) wants to try a good amp for their M80s on the cheap it is a very good one to start with. That amp has some serious balls.
Posted By: WhatFurrer Re: two amps? - 06/20/07 10:35 PM
I'm seriously looking at it...

May be able to drive to San Antonio and pick it up... Definitely be willing to if I were to win the auction...

Hmmmm....

WhatFurrer
Posted By: Wid Re: two amps? - 06/21/07 12:10 AM
It is certainly worth a bid or two. If that amp goes for under $200 it will be a steal. That is of course it is in great working order.
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