Quick question about 5.1 receivers and stereo...

[SJTrance]

So, I have a Pioneer VSX 90TXV receiver. I'm just curious about one thing. So, if I'm using the 5 channels, I should be getting around 110 Watts per speaker. If I only use 2 channels, does that mean that I still only get 110 watts for those two stereo speakers?

 

[markw]

Well.....

It's a ratings game and they play with the specs.

The fact of the matter that maybe, just maybe, two channels might put out 110 watts per channel with some caveats if that's all that's being driven. But, I can guar-on-tee that if you've got all channels cookin' at the same time, you're getting a whole lot less than that per channel then you think.

While this is not real biggie if you're watching a movie but if you've got one of those "all channels stereo" things goin' on and you're cranking it, odds are you're running out of power.

If you want to keep on believing what you currenty do, take the blue pill but, if you're really up to it, here's the red pill

 

[SJTrance]

Haha. I like your method of explanation. Yes, I do believe that most manufacturers blotch up the numbers a bit. That being said, I'm quite happy with the amount of sound that my receiver puts out even though it's outdated. It's clean, quiet and makes me happy all over. I'd love to see the link that you posted, but I think it's not working.

So, to sum it up, I suppose that they advertise that the power is supposed to be equal all around whether I do a 7 channel, 5 channel or 2 channel, but in real world situations, the 2 channel power will be more than the 7 channel, right? Of course, I may not be getting the fully advertised 110W/channel.

 

[Shakeydeal]

It's a receiver, you can't expect too much out of it. Think about it.

You have one box with:

amplifier
preamplifier
processing crap for 5.1 channels
tuner

And it weighs (typically) around 40 lbs. When you cram all that into one box, corners must be cut and performance suffers. And as stated above, the specs for receivers are pretty sketchy.

Home Theater and music are best when separated.

Shakey

 

[MDS]

So, to sum it up, I suppose that they advertise that the power is supposed to be equal all around whether I do a 7 channel, 5 channel or 2 channel, but in real world situations, the 2 channel power will be more than the 7 channel, right? Of course, I may not be getting the fully advertised 110W/channel.

Receivers are always rated with 2 channels driven. This is an FTC standard and is clearly stated in the manual of most receivers. There was a proposed standard for multi-channel that was something like 2 channels driven to full power and the rest driven at 1/8 power but it never caught on and I've never seen such a power rating listed in any specs for any receiver.

The problem is the specs state '100 x 7' and people assume that means 110 wpc when all channels are driven simultaneously even though the specs clearly say 2 channels driven. Harmon Kardon is the only manufacturer that (used to) rate their receivers with all channels driven and that is why their models have much lower numbers.

With few exceptions, receivers use a shared power supply and power is allocated as needed among the channels. If you're only using 2 channels, playing a stereo source, you will get the advertised rating.

 

[markw]

D'oh!

Haha. I like your method of explanation. Yes, I do believe that most manufacturers blotch up the numbers a bit. That being said, I'm quite happy with the amount of sound that my receiver puts out even though it's outdated. It's clean, quiet and makes me happy all over. I'd love to see the link that you posted, but I think it's not working.

So, to sum it up, I suppose that they advertise that the power is supposed to be equal all around whether I do a 7 channel, 5 channel or 2 channel, but in real world situations, the 2 channel power will be more than the 7 channel, right? Of course, I may not be getting the fully advertised 110W/channel.

Sounds like you've got it.

Sorry about the fumbled link. Try this one. It's a good explanation from this very same site.

 

[3db]

It's a receiver, you can't expect too much out of it. Think about it.

You have one box with:

amplifier
preamplifier
processing crap for 5.1 channels
tuner

And it weighs (typically) around 40 lbs. When you cram all that into one box, corners must be cut and performance suffers. And as stated above, the specs for receivers are pretty sketchy.

Home Theater and music are best when separated.

Shakey

uh huh Ever look at NAD before? All of their HT receivers meet or exceed ACD at full bandwidth as long as they don't exceed draw from the wall outlet. But then again, power amps have that same problem.

 

[Shakeydeal]

All of their HT receivers

It is still a RECEIVER. He is interested in high quality two channel music reproduction, or at least that's the way I read it.

Shakey

 

[GranteedEV]

It is still a RECEIVER. He is interested in high quality two channel music reproduction, or at least that's the way I read it.

Shakey

Hi.

When you have no idea how electronics actually work, go actually learn before you comment.

amplifier
preamplifier
processing crap for 5.1 channels
tuner

Wow. Four simple sections. One of which is usually turned off unless in use.

The fact is that only an amplifier will ever generate the type of heat that requires heatsinking (whcih btw, is where the heat is, and in any class A/B amplifier is nothing like the pointlessly inefficient Class A and Vacuum Tube amps you probably have faith in sounding better). Tuners and Pre-amplifiers are extremely simple devices, and processors use very tiny, efficient microchips.

Is it sufficient for multichannel music? Not likely if high SPLs are a goal. For stereo music 100wpcx2 is just right.

 

[Shakeydeal]

I know enough about electronics to know that receivers are inferior to separates or well designed integrated amps when it comes to reproducing music. But thanks for your concern about my education, much appreciated.

 

[KEW]

Different manufacturers exercise differing degrees of hyperbola in their specifications.
However, as an example, here is a $1250 MSRP Marantz SR6004 which is rated at 110 watts x 7 (8 ohms):
Scroll down to the table labeled "Marantz SR6004 Tabulated Power Measurements"
http://www.audioholics.com/reviews/receivers/marantz-sr6004-1/sr6004-measurements

This should give you a sense of the overall trends when you are going from 2 channel to 7 channel.

PS - You need to take Shakeydeal's comments with a grain of salt. He claims he can hear substantial differences between receivers and amps, and even between different amps. However, when presented with the opportunity to so enlighten the audio world (and make $10K!) via a double blind test, he gets all squirrely.

http://www.tom-morrow-land.com/tests/ampchall/index.htm
http://www.tom-morrow-land.com/tests/ampchall/rcrules.htm

 

[zumbo]

There sure does seem to be a lot of shunning going-on around here these days, and I am finding it quiet disturbing. I don't know what has went-on with Shakeydeal in other threads, but he is getting a lot of down talking in this one.

As has been clearly pointed-out by everyone, av receivers are pulling your leg. If the unit is 110w, one should assume it has the ability to do 110 x 2.

Now in Shakeydeal defense, a separate amp claiming 110 x 7 certainly has the ability to do 110 x 7. Why he is catching flack for that makes no sense to me what-so-ever.

 

[GranteedEV]

Now in Shakeydeal defense, a separate amp claiming 110 x 7 certainly has the ability to do 110 x 7. Why he is catching flack for that makes no sense to me what-so-ever.

Because it doesn't matter if it can do 110W x 7 for stereo listening.


All Shakeydeal cares about is implying that his tube monoblocks, cable raisers, expensive cables, etc all have a special hi fi sound that recievers can't match even when all are properly driven.

 

[zumbo]

Because it doesn't matter if it can do 110W x 7 for stereo listening.


All Shakeydeal cares about is implying that his tube monoblocks, cable raisers, expensive cables, etc all have a special hi fi sound that recievers can't match even when all are properly driven.

Didn't see it in this thread. My first thread to see a Shakeydeal reply.

 

[GranteedEV]

Didn't see it in this thread. My first thread to see a Shakeydeal reply.

Well, expect such 6moons mantra as "If it's not a dedicated 2ch listening room, then it is for jurrassic park", that multich separates processors are inferior to 2ch analogue preamps, that all solid state amps sound "grainy", and that one simply needs a resolving system to hear the differences in cables, and that measurements don't tell you a thing about how something sounds.

You know, the type of B.S. that the subjective magazines will tell you to please their advertisers. Oh, and apparantly this board has no interest in "real hi-fi".

I'm not gonna lie though, I really don't have much interest in magic and voodoo.

 

[zumbo]

Well, expect such 6moons mantra as "If it's not a dedicated 2ch listening room, then it is for jurrassic park", that multich separates processors are inferior to 2ch analogue preamps, that all solid state amps sound "grainy", and that one simply needs a resolving system to hear the differences in cables.

You know, the type of B.S. that the subjective magazines will tell you to please their advertisers.

Oh, and apparantly this board has no interest in "real hi-fi".

I actually can agree with part of that.

If everyone here felt my Yamaha Z7 was the best receiver in the world, and everyone used that receiver, we wouldn't have much to talk about.

On another note, I just use my Z7 as a pre-amp. Which, in my mind, would put me in the camp of thinking separates were better.

On another note, my HT is superior to any I have heard. But, I am working on a dedicated 2-channel rig.

And, none of this difference of opinion has anything to do with the fact of the OP's question.

So, I have a Pioneer VSX 90TXV receiver. I'm just curious about one thing. So, if I'm using the 5 channels, I should be getting around 110 Watts per speaker. If I only use 2 channels, does that mean that I still only get 110 watts for those two stereo speakers?

 

[GranteedEV]

You're right, I really never addressed it properly did I?

So, I have a Pioneer VSX 90TXV receiver. I'm just curious about one thing. So, if I'm using the 5 channels, I should be getting around 110 Watts per speaker. If I only use 2 channels, does that mean that I still only get 110 watts for those two stereo speakers?

First we need to stop thinking of wattage as being wattage.

The first assumption we're forced to make when discussing wattage is that we're talking about flat 8-ohm loads.

Okay, fine. Let's assume your speaker is a flat 8-ohm load (chances are it isn't and this is another issue that must be considered)

I'm going to choose a speaker that fits this criteria:

http://www.salksound.com/pharos high-efficiency - home.htm

Now let's imagine we've got seven of them in a multi-channel listening room.

First of all, what does 110 watts mean to us? It means that into this 8 ohm load, a given amplifier channel is capable of 29.7v RMS.

Now we know one thing, and that is that the speaker I went with has a sensitivity of 95db/w/m which into an 8 ohm load is also 95db/2.83v/m

What we know about that is that it's extremely loud. And since it's an easy load, it will not tax the amplifier at 2.83v.

Now most entry level receivers will give you a rating into a stereo load x 7. What does this mean? It means at any given time, at the very least, any given speaker (or two) can have 29.7v RMS being driven through it.

The key word above is "can".

With regards to a stereo recording, it means that at any given time, two speakers "can" get as loud as ~115.5db at 1m

Now this of course is extremely loud. Most speakers are not as efficient as the Pharos so this is an anomally - it's a solid 7-8db above the average loudspeaker in efficiency. Anyways, at least with respect to movies, if listening at reference levels this means the signal "can" get as loud as 105db at the listening position (keep in mind losses due to distance).

So anyways if two speakers at a time are capable of 115db in this scenario - you must ask yourself - will the signal often ask for each speaker to produce this output?

In the case of most content, this is doubtful. Chances are, you will not even have 1vrms per channel... never mind 30vrms/channel!

So is it of much use to us to have a receiever capable of 110w x 7 - all channels driven at the same time? IMO not really. As long as a given speaker, when the signal calls for it, can have that peak power, it's all you need.

The first issue that arises is the amount of current you even have on tap. Most 110/120v lines will have 15a circuits installed. In order to draw any more you would need to have a 20, 30, or 50a or 220/240v circuit installed!

Second most people don't even watch movies too loud. On average, you'll be using less than 1v for the front speakers and absolutely negligible power out of the surrounds. You would only approach those 30v peaks occasionally and almost never at the same time between the surrounds and fronts.

Where having lots of all channels driven performance on tap is useful is a 5.1 channel blu ray or dvd-a or sacd type recording. These multi channel recordings can have a ton of dynamic content in each channel at the same time. But they are niche products and the average person buying an entry level receiver won't be too concerned with them.

Gaming is an intersting scenario as it does often use surround channels at high intensities for a constant load. If you plan on gaming at loud volumes may benefit from a 7-channel amp such as the Emotiva UPA-7 or ATI 1807.

When purchasing amplifiers, don't be too hung up on all-channels-driven performance. A more useful amplifier measure is its 2 channel RMS output into 4 and occasionally 2-ohm loads as this implies high current capability for any given channel. You likely won't use all 7 channels at the same time, but it's more likely your speakers have low impedance dips. At least not for movies or stereo listening.

If you aren't too interested in high volume gaming or multichannel music, but do feel unsatisfied with the amp channels in your receiver (which is usually plenty though) then a two or three channel amp for your fronts, and letting your receiver power the surrounds, is probably going to be a good option.

 

[SJTrance]

Man, things are getting heated here. All I really wanted to know was whether a receiver will make more power for two channels than when powering for all 7 channels. I believe that question got answered for me. I am aware of the hopped up numbers a lot of manufacturers are giving out. I am not aware of anything from Shakeydeal but the following argument in the thread did make me aware that he was selling some "hi-fi" components. I guess it doesn't make any difference to me since I have no interest in getting an amp or anything.

 

[markw]

You chose .....well.

Man, things are getting heated here. All I really wanted to know was whether a receiver will make more power for two channels than when powering for all 7 channels. I believe that question got answered for me. I am aware of the hopped up numbers a lot of manufacturers are giving out. I am not aware of anything from Shakeydeal but the following argument in the thread did make me aware that he was selling some "hi-fi" components. I guess it doesn't make any difference to me since I have no interest in getting an amp or anything.

Along with the wheat offered here, some chaff occasionally slips in. You seem t be able to differentiate between the two.

Unless you're an anal snob with the ears of a dog or easily buy into some of the snobbish BS being sold in this hobby, you can get some pretty fine sound out of some receivers if you trust your ears, particularly in two-channel, direct mode.

Did that link help explain it a little better?

 

[zumbo]

You're right, I really never addressed it properly did I?

Now, that was a useful post!