ALL-Channel driven simultaneously power tests anyone?

[jeannot]

Does anyone have a link to a bench test of any modern 7.x channels receiver, where all the channels are driven simultaneously?

So far looks like a Taboo to me, where anyone who questions whether the emperor has clothes can be burned on a stick.

 

[sholling]

You might find this analysis interesting.

 

[jeannot]

You might find this ... interesting.

Yep. Just an article about emperor's clothing problem not being a big deal.

I still want to see the emperor though.

 

[BoredSysAdmin]

I think this is better one:http://www.audioholics.com/education/amplifier-technology/the-all-channels-driven-acd-amplifier-test

 

[jeannot]

Guys, I would like an article where a real Receiver, one with a brand, has been put on a bench with known resistive loads on each and all of its channels, taken to clipping at an audible frequency, and measurements taken and I can read the results in Watts expressed in the Arabic numbering system.

 

[Rickster71]

What do you hope to gain that info?

Even if a receiver can pass an ACD test in a lab hooked to a Variac, it probably won't happen at home on a 15 Amp circuit.
They're simply design limitations to the receiver's single box containing 5 amps, with them being supplied with the same 15 amp plug.
Since with real world use, movie or music content doesn't load all channels with the same content at the same time anyway. So a receiver is lab tested for an ACD situation that it will never encounter in most or even all set ups.

If a large home theater needs that much power; a pre amp and separate amps for each channel, all on dedicated 20 Amp circuits would better fit the bill.
Just my 2 cents.

 

[j_garcia]

One of the stereo rags used to publish bench tested ratings. Not sure if they still do, but my buddy who used to have a spreadsheet maintaining their published numbers at one point, but I doubt he still does it. It isn't "taboo" it is "work" that someone has to do, and since it ultimately doesn't sell receivers (and may actually invalidate manufacturer's marketing claims), you aren't going to see it tossed out there much.

 

[GranteedEV]

Guys, I would like an article where a real Receiver, one with a brand, has been put on a bench with known resistive loads on each and all of its channels, taken to clipping at an audible frequency, and measurements taken and I can read the results in Watts expressed in the Arabic numbering system.

... the question is... Why.. when it isn't a real world scenario?

A far more relevant test for any amplifier is a powercube, because it tells us how the amplifier performs in real world scenarios. For example:

http://theaudiocritic.com/plog/index.php?op=ViewArticle&articleId=22&blogId=1

As a general rule, with a few exceptions (NAD) most receivers do not have the current supplies for ACD output. You can expect about 30 to 50% of 2 channels driven power into ACD. If you want ACD, you need separates amp, plain and simple.

 

[jeannot]

What do you hope to gain that info?

Let's see, reading your signature I would answer: Because it is the truth.

Even if a receiver can pass an ACD test in a lab hooked to a Variac, it probably won't happen at home on a 15 Amp circuit.
They're simply design limitations to the receiver's single box containing 5 amps, with them being supplied with the same 15 amp plug.
Since with real world use, movie or music content doesn't load all channels with the same content at the same time anyway. So a receiver is lab tested for an ACD situation that it will never encounter in most or even all set ups.

They use sine waves for testing. Most of us don't listen to sine waves, but we still want these numbers.

 

[jeannot]

... the question is... Why.. when it isn't a real world scenario?

Is listening to sine waves in your living room a "Real World Scenario"?
All tests are performed with sine waves, and you read those numbers.

I think questioning one's question borders on rudeness.

 

[GranteedEV]

Is listening to sine waves in your living room a "Real World Scenario"?
All tests are performed with sine waves, and you read those numbers.

THOSE numbers represent real world scenarios. The test tone is a sine wave, but the represents an amplifiers ability to drive a load into one or two channels, just like in the real world where surround channels neither tax a system full tilt nor do they continuously run simulatenously with all channels driven. Two channels continuously driven though? Most certainly. Dips as low as 2 ohms? definitely.

We want correlation with real world scenarios. And if your surround channels are being driven hard enough to drive a receiver to its max rated 2 channel driven power, then you're listening to the sort of multichannel recording which demands dedicated separates amplifiers such as the ATI 2005. This is a niche scenario, not a common one in the real world.

Sine waves don't represent audio content, but they represent the interaction of an amplifier with a presented (normally resistive) load into one or two channels. What real world scenario does ACD testing REPRESENT?

 

[Buckster]

theres got to be something in it though - coert of UltimateAVmag - this was how my Pioneer 59TXi tested: - 133W 7 channels driven and 180 odd 4 ohms - not bad at all

http://www.ultimateavmag.com/content/pioneer-vsx-59txi-av-receiver-measurements

did the AV receiver seem more dynamic than the Arcam AVR350 (tested at 90W /7 channels or there abouts), my Pioneer 45Tx, or Yamaha 3800

yup of course - even at lower volumes

 

[jeannot]

GranteedEV, don't you think that insisting that one question is irrelevant, is kind of rude?

Don't you think people have the right to ask a question without it, or the person being attacked?

 

[jeannot]

theres got to be something in it though - coert of UltimateAVmag - this was how my Pioneer 59TXi tested: - 133W 7 channels driven and 180 odd 4 ohms - not bad at all

Hey, thanks Buckster! It appears some people see the point after all.

 

[InTheIndustry]

GranteedEV, don't you think that insisting that one question is irrelevant, is kind of rude?

Don't you think people have the right to ask a question without it, or the person being attacked?

You absolutely have the right to ask a question. However, if you're relying on other people to work for you to answer it for you then perhaps you should be kind enough to discuss your line of thinking or the origin of the question with them if asked. Is that unreasonable? Perhaps you saw, heard, or read something that none of us have ever considered and that lead to your question? I, for one, would be interested in what you found if that were the case & I bet so would others.

I also didn't see anyone attacking or going off on you. Maybe some snarking back and forth, but who started that is debateable. I hope you get your question, whatever the point, answered as best as possible.

 

[mtrycrafts]

Does anyone have a link to a bench test of any modern 7.x channels receiver, where all the channels are driven simultaneously?

So far looks like a Taboo to me, where anyone who questions whether the emperor has clothes can be burned on a stick.

There used to be one from one of the mags but most likely of older 5 ch receivers. Nothing audio is taboo here, but the answers may not be to your liking.
The question may be asked why is that so important? What source has full scale signal to all channels at the same instant? Seconds apart does not qualify.

 

[jeannot]

InTheIndustry, the very first sentence of GranteedEV was: "... the question is... Why.. when it isn't a real world scenario?" Does that question give the sense that someone is trying to help me?

The proper answer of the curious and respectful one should have been "Not off the top of my head, but I am curious at to why you ask".

Then, I would have returned the courtesy by answering that two amplifiers may give the same power in stereo, but one of them half that in 7 channel mode because the manufacturer skimped on the power supply. That can also be an indication that they also may be skimped on the output transistors SOA, display and relays MTBF, etc... The weight, power consumptions are other indicators but I believe they are more debatable.

I understand that you want to dampen the discussion, but I remained courteous all along. All I did is ask why my question was not respected.

When people disapprove of a question, staying OFF the thread is always the best course of action. Unless they have something to prove.

 

[jeannot]

mtrycraft, thank you for your question. I think I touched it a bit in the previous post.

I agree 100% that good ACD performance is a sure sign of over-engineering.

However, one thing all the machines have in common is that the ones that approach perfection always appear over-engineered to the majority of people.

Does one NEED a dodge viper? I certainly don't, and do not see the point. BUT, I still have to be able to appreciate the engineering, and rejoice at seeing people realizing their dream if it was to own one.

 

[PENG]

Does anyone have a link to a bench test of any modern 7.x channels receiver, where all the channels are driven simultaneously?

So far looks like a Taboo to me, where anyone who questions whether the emperor has clothes can be burned on a stick.

Here you go, enjoy, and don't forget to write us a book report.......

http://www.hometheater.com/content/denon-avr-3808ci-av-receiver-ht-labs-measures

http://www.hometheater.com/content/pioneer-elite-sc-37-av-receiver-ht-labs-measures

http://www.hometheater.com/content/nad-t-747-av-receiver-ht-labs-measures

http://www.hometheater.com/content/denon-avr-4310ci-av-receiver-ht-labs-measures

http://www.hometheater.com/content/integra-dtr-99-av-receiver-ht-labs-measures

http://www.hometheater.com/content/yamaha-rx-z11-av-receiver-ht-labs-measures

There are some British ones:

http://hcc.techradar.com/reviews_archive?filter0=142&filter1=&filter2=

 

[PENG]

yup of course - even at lower volumes

The way you put it I can agree with you. On the other hand this kind of undefined remarks could be one reasons of myths and hearsays that just keep on going around and around for years.

I am sure it is all good intention but unless you define "lower volumes", someone is going to recycle it, and then someone else would recycle it again, and again, and eventually you will see, as I have, that it may turn into something like:
..............even at low volume...., without once again, defining "low" (as opposed to the original "lower") volume.

In the end, some readers would be led to believe that everything being equal a 300W amp will sound much better, more details, more dynamic, than a 150W amp even at low volume, with the amp presumably putting out a couple of watts, with occasional instantaneously peaks of 128W or 18 to 21 dB higher. Now then that would defy physics.