Choose an amplifier for me

[dponeill]

First of all that is called dynamic range (130db). 2nd of all you are speaking of what the ear perceives. Just because your ear is a nonlinear device doesn’t mean that 3db isn’t twice as loud, it is. Please don’t tell me I’m wrong when you are comparing your apples to my oranges. How do you know that he isn’t sitting 70ft away from his speakers and the average SPL at his position is 85dbm, so an increase of 3db would be measured as twice as loud, and perceived as twice as loud. 3db is twice as loud period.

I hate to tell you this, but Markw is right.

 

[MacManNM]

I hate to tell you this, but Markw is right.

If you read the article it basically says that the ear is nonlinear. At higher levels the responsivity changes. It totally depends on the ambient noise and the spl at the listening position. So in reality we are both right, just I'm a little more right. it is all a matter of perspective.

The poster said he wants the neighbors to hear his system, since they are in the far field the 3db gain is going to seem much greater to them moreso than to the person sitting in front of the TV.

 

[Snap]

Amp Choices.

WOW so many amp choices to check on. We are really answering the posters question.

Forgot one amp to also take a look at. Please add Rotel to the list.

 

[MDS]

So in reality we are both right, just I'm a little more right. it is all a matter of perspective.

Is that your way of conceding that you are wrong?

The perception of loudness is subjective and varies with frequency. The fact that the ear perceives increases in sound in a logarithmic fashion means that at the extremes it takes far greater increases in SPL to perceive any difference at all. The difference between 20 Hz at 100 dB and 20 Hz at 103 db is inaudible - not double. Likewise for high frequencies. 10 db equaling double the perecived loudness is a general rule. In reality, it can vary with frequency and be anywhere from 6 dB to 10 dB.

10*log(100/50)=3.01 dB. Doubling the power yields 3 dB increase in SPL output. 70 feet away, the neighbors aren't going to hear any increase in volume at all as every doubling of distance drops the SPL by about 6 dB.

 

[MacManNM]

Is that your way of conceding that you are wrong?

The perception of loudness is subjective and varies with frequency. The fact that the ear perceives increases in sound in a logarithmic fashion means that at the extremes it takes far greater increases in SPL to perceive any difference at all. The difference between 20 Hz at 100 dB and 20 Hz at 103 db is inaudible - not double. Likewise for high frequencies. 10 db equaling double the perecived loudness is a general rule. In reality, it can vary with frequency and be anywhere from 6 dB to 10 dB.

10*log(100/50)=3.01 dB. Doubling the power yields 3 dB increase in SPL output. 70 feet away, the neighbors aren't going to hear any increase in volume at all as every doubling of distance drops the SPL by about 6 dB.

No, and that is the point I am trying to make. The ear is nonlinear. Now the neighbors will hear a 3db increase. There is a thing called gain (house rooms etc) in this equation. This is not isotropic radiation we are speaking of here.

 

[MacManNM]

Boy I would like to know who the yellow bastard is that gave me a red chicklet for this post: http://forums.audioholics.com/forums/showthread.php?p=110829#post110829

and left this comment:
"Not enough knowledge for such opinionated statements"

Now let's do a little test, take a 5ch amp and plug it into an outlet, then take 3 2ch amps and use a single plugstrip to plug them into an outlet. Then let's pulse the input with a 100ms pulse into a 4 or 8 ohm load. Which one is going to have a higher output? Feel free to PM me if you don't have the guts to reply on this thread.

 

[mtrycrafts]

The total capacitance is increased when using multiple amps. That increase equates to more available peak power per channel.

I am a bit dense here on this. But how in the world one channel benefits form another amps capacitors in a discrete amp??? I seriously doubt it does.

On the other hand, a multi channel amp may have access to the total capacitance for each channel. And, since you don't have peak powers to all the channels at the exact same time, your separate amps is no better than the one amp, is it??? But please fully explain how these other caps will help one channel; int he separate amps? After all, I want to learn from the pros.

 

[mtrycrafts]

3db is twice as loud.

And in the last post I wanted to learn from the pros???

I will find better sources.

10dB spl is perceived as twice as loud. Even I know that.

 

[mtrycrafts]

First of all that is called dynamic range (130db). 2nd of all you are speaking of what the ear perceives. Just because your ear is a nonlinear device doesn’t mean that 3db isn’t twice as loud, it is. Please don’t tell me I’m wrong when you are comparing your apples to my oranges. How do you know that he isn’t sitting 70ft away from his speakers and the average SPL at his position is 85dbm, so an increase of 3db would be measured as twice as loud, and perceived as twice as loud. 3db is twice as loud period.

Twice as loud to what? Not your ears, so it is irrelevant, isn't it?

 

[eddiem67]

Earthquake Cinenova 5 will do 300X5 @ 8 ohms, 600x5 @ 4 ohms. For 2450.00 (retail 3999.00) you can't go wrong. with XLR inputs as well.

You can also do 5 Byrston 7B SST like the movie theaters do.

 

[mtrycrafts]

Boy I would like to know who the yellow bastard is that gave me a red chicklet for this post: http://forums.audioholics.com/forums/showthread.php?p=110829#post110829

and left this comment:
"Not enough knowledge for such opinionated statements"

Now let's do a little test, take a 5ch amp and plug it into an outlet, then take 3 2ch amps and use a single plugstrip to plug them into an outlet. Then let's pulse the input with a 100ms pulse into a 4 or 8 ohm load. Which one is going to have a higher output? Feel free to PM me if you don't have the guts to reply on this thread.

Oh, your turn on the chopping blocks with those chicklets.

Oh, you want to pulse all channels at the exact same time??? Why???

How is that relevant to playback of a 5 ch movie, or music???

It is irrelevant, totally. You made a test bench question. So what. Irrelevant to real world playback.

 

[MacManNM]

I am a bit dense here on this. But how in the world one channel benefits form another amps capacitors in a discrete amp??? I seriously doubt it does.

On the other hand, a multi channel amp may have access to the total capacitance for each channel. And, since you don't have peak powers to all the channels at the exact same time, your separate amps is no better than the one amp, is it??? But please fully explain how these other caps will help one channel; int he separate amps? After all, I want to learn from the pros.

I never said that one amp can "help" another.

So you are saying that peaks happen one channel at a time and never happen simultaneously? Don't think so. So, yes there is more available peak power from multiple amps, due to the increase in capacitance. Besides even if it were one channel at a time, the recovery time for one amp would be slower than several separate amps, each with its own power supply.

 

[MacManNM]

And in the last post I wanted to learn from the pros???

I will find better sources.

10dB spl is perceived as twice as loud. Even I know that.

I guess you don't know that. Read the papers, it depends on the frequency. Hence the term nonlinear, both frequency and amplitude.

 

[MacManNM]

Oh, your turn on the chopping blocks with those chicklets.

Oh, you want to pulse all channels at the exact same time??? Why???

How is that relevant to playback of a 5 ch movie, or music???

It is irrelevant, totally. You made a test bench question. So what. Irrelevant to real world playback.

It is totally relevant. Most music/movies put the most strain on the front towers and center, ergo peaks will happen on all three channels at the same time. Now, lets say you have a 3 ch amp with X capacitance, and on the other hand you have two 2/ch amps (leave one channel unused) with 2X capacitance. Which is going to have more dynamic range? We will assume that all of these are of the same build quality, same power supply. Just that the 3ch amp shares one.

 

[mtrycrafts]

It is totally relevant. Most music/movies put the most strain on the front towers and center, ergo peaks will happen on all three channels at the same time.

And you have spectro analysis of this to prove your assertion? I seriously doubt it. After all, it doesn't need to be time differences much not to matter, cap recharge times?



Now, lets say you have a 3 ch amp with X capacitance, and on the other hand you have two 2/ch amps (leave one channel unused) with 2X capacitance. Which is going to have more dynamic range? We will assume that all of these are of the same build quality, same power supply. Just that the 3ch amp shares one.

Only relevant if you have a peaks at the exact same instant. No evidence to prove that that that is what happens in reality. You need more than just hearing analysis; precision scope comparison is what is needed. Caps do recharge quickly.

But to your question: if the two channel amps are mono blocks with their own caps, they have some advantage with exact timing peaks only. But, if the 2 ch amp shares the caps, your advantage is slim.
In reality, you don't have music like that, or movie tracks. I want to see the traces precisely timed and compared

 

[mtrycrafts]

I guess you don't know that. Read the papers, it depends on the frequency. Hence the term nonlinear, both frequency and amplitude.

I read the acoustic book by Alton. I guess he may be wrong a bit.
In any event, you will not get twice the perceived loudness from 3 dB spl change at any frequency.

 

[mtrycrafts]

I never said that one amp can "help" another.

So you are saying that peaks happen one channel at a time and never happen simultaneously? Don't think so. So, yes there is more available peak power from multiple amps, due to the increase in capacitance. Besides even if it were one channel at a time, the recovery time for one amp would be slower than several separate amps, each with its own power supply.

Yes, more or less. You don't have peaks at exact same times in all channels or most, maybe not even in two. About that recovery time, how long is it exactly? And why would the recovery times be that much slower between multi channel and 2 ch amps? Don't buy it.

 

[MacManNM]

Yes, more or less. You don't have peaks at exact same times in all channels or most, maybe not even in two. About that recovery time, how long is it exactly? And why would the recovery times be that much slower between multi channel and 2 ch amps? Don't buy it.

Look at some data of real music or movie content, the front's will have peaks at the same time.

You don't buy it because you don't understand it. The recovery time can't be any faster than 16ms (20 ms if you live across the big pond). Now, if your peak is 60 Hz or lower they won't recover in time.

 

[Dan Banquer]

Amps

Since this is a hot one let me add some fuel to the fire here as I have just started to do some research into this. I talked with Dave Moulton who is a recording engineer who does surround, and consults with firms doing the megabuck surround installations in this area. For more info try www.moultonlabs.com

In any case we were talking about this general subject very recently. Typically peaks for HT or Multi Channel are 20 mS to 25 mS in duration and most of this is bass. Typical spl peaks are 110db/spl at the loudspeaker and Dave tells me that practically no one can stand peaks any higher than this, because this starts to get well......uncomfortable. These peaks can happen in two to three channels simultaneously. Usually the sub, and right and left front. It is extremely rare (when the movie goes into an end of the galaxy routine) that peaks occur in all 5 channels, and if they do the spl peaks at the speaker are down to 100 db/spl.( approximately 10 watts peak?) Think about 5 or 6 speakers coming at you with those levels!
Now if we are using an HT set up with a powered sub, then the duration of the peaks go down for the receiver, probably in the range of 10mS at most. If we are using a 90db/spl speaker (typical for HT) than 100 watts peak (110db/spl at the speaker), and the speaker is the typical 8 ohms nominal with an absolute minimum of 4 ohms, then as far as I can tell the receiver is not asked to do a heckuva lot.
If the system has no powered sub, then the demands come up to 25 mS for two to three channels. It appears at this point, unless your running some of the heftier receivers, you may have issues.
Hope this helps;
d.b.

 

[mtrycrafts]

Look at some data of real music or movie content, the front's will have peaks at the same time.

You don't buy it because you don't understand it. The recovery time can't be any faster than 16ms (20 ms if you live across the big pond). Now, if your peak is 60 Hz or lower they won't recover in time.

What? Caps cannot recharg faster than this? Really?