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FTC Power Amplifier Rule

Spkrdctr

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I'd guess at least half.
It is so easy to run in 2.1 that a lot of people bounce back and forth. Me included! But in doing so, the multi-channel always sounds much better. Plus multi-channel covers up a lot of room sins too. Not perfect of course but can really help in hard to set up rooms.
 

sarumbear

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None of the systems I'm thinking of use AVRs, they use pre-pros.
What is a pre-pros?

The worldwide AVR Market Size Worth $2.61Bn. That is more than half a million units sold every year. Someone is using them.

I've never actually seen an Atmos set-up in the wild; only at a dealer.
I’m surprised with the lack of spatial audio. My dealer have installed 20+ HTs during the lockdown, all with spatial audio. There are at least ten such companies in our area, which has a population of less than a million. Go towards London, there are 100+ companies for a population of 10+ million. Those companies nominate hundreds of entries of their HT installations, again almost all with spatial audio, every year.
 

MakeMineVinyl

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That was EXACTLY what we were telling them. Class D all the way with say 150 at 4ohms for L/C/R all driven at once and the surrounds all had to do 70% of the 150 at 4 ohms to pass. This means class D and if they wanted split the power supplies from everything else in a two box configuration that would be fine. This also means the pre box could increase its measurable (by Amir) performance and bring surround sound up A LOT in the tests. Of course the amp is then just a 7 or 9 channel amp. Very easy, yet none of the majors are willing to go there. They refuse to do what I want done. Can you believe that??:)
The ATI NC500 series amps from ATI I believe can be had in 3 and 5 channel versions up to 500 watts. The amps also come in 500 watt monoblocks, and I think high power/low power configurations are made. They don't make a 9 channel in that series, but I think they do make a 9 and 11 channel in another model series. These were made specifically for Atmos.
 

blueone

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sarumbear

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The Dolby Atmos site lists 5.1.1/2 as a valid Atmos speaker configuration:
Correct. The number after the dot shows the number of spatial channels/speakers. You said 5.1 and 5.2. That means no spatial channels.
 

blueone

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That’s is generally called an AVR. Check Google. Some call it an AVP but in general I think the term AVR is not wrong.

Correct. The number after the dot shows the number of spatial channels/speakers. You said 5.1 and 5.2. That means no spatial channels.
AVP is another term used for a pre-pro. AVR refers to a receiver, which contains amplifiers. At least in the US.

I edited the post to delete the reference to 5.x.x. In my haste I misinterpreted what the numbers meant, so my remark made no sense.
 

jhaider

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Query: isn’t there a CTA amp power spec that could be formally adopted?
 

sarumbear

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AVP is another term used for a pre-pro. AVR refers to a receiver, which contains amplifiers. At least in the US.

I edited the post to delete the reference to 5.x.x. In my haste I misinterpreted what the numbers meant, so my remark made no sense.
I deleted my post too. :) I removed my comments on AVR.
 

rdenney

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It’s a fact that centre channel has more signal than LR on almost all soundtrack, hence stereo is not relevant in movies. If I was FTC I would say LCR driven at 100% and all other surround and spatial channels at 50%.
Except that lots of content, including old movies and not just music, are in stereo. Test protocols should follow use cases—here are the specs for stereo listening, here they are for 7.2 surround sound, here they are for 11.2 Atmos, or whatever. (My thinking only goes up to 7.2.)

If receiver manufacturers sized their amps and power supplies appropriately to content use cases, surround channels would have and be happy with a lower rating.

Rick “requirements derive from use cases; tests and specifications should derive from requirements” Denney
 
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sarumbear

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Except that lots of content, including old movies and not just music, are in stereo. Test protocols should follow use cases—here are the specs for stereo listening, here they are for 7.2 surround sound, here they are for 11.2 Atmos or whatever.

If receiver manufacturers sized their amps and power supplies appropriately to content use cases, surround channels would have and be happy with a low rating.

Rick “requirements derive from use cases; tests and specifications should derive from requirements” Denney
Just sample the top 50 streaming and cinema releases and see the results.

Surround audio has became a cinema standard 30 years ago, Atmos is almost a decade old. Standards are released for the current environment. You don’t release a standard to satisfy half a century old materials!
 

rdenney

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Just sample the top 50 streaming and cinema releases and see the results.

Surround audio has became a cinema standard 30 years ago, Atmos is almost a decade old. Standards are released for the current environment. You don’t release a standard to satisfy half a century old materials!

I’ll say this again: not everyone streams. High-speed Internet infrastructure will have to be a lot more comprehensive than it is now to assert otherwise.

Also: People I know own (stereo) CDs and play them, usually in their HT systems.

Rick “who owns lots of DVDs with 5.1 surround encoding” Denney
 

sarumbear

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I’ll say this again: not everyone streams.
I’ll say this again: not everyone streams. High-speed Internet infrastructure will have to be a lot more comprehensive than it is now to assert otherwise.
Time to go out and see the world.

Other than Africa and Americas the world has gigabit Internet and streaming is the major means to watch films.
 

rdenney

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Time to go out and see the world.

Other than Africa and Americas the world has gigabit Internet and streaming is the major means to watch films.

The world is what it is.

Do you think South Asia has gigabit outside of the biggest cities? Rural China? Rural Australia? Maybe Europeans and big-city Americans are the ones who need to go out and see the world.

But even my friends who have good Internet also have CD and DVD libraries. And lots of stereo content is still being made and sold.

As for me, I have a system built for music. It is stereo, though I may add subwoofers at some point. I have literally zero multichannel content that I would play on that system. I also have a home theater system that my wife occasionally uses for CDs, but mostly it’s for watching TV (DirecTV—the only option where we live except for the OTA antenna). We also have a DVD library, so most movies for us are on premium movie channels or the shelf. Most content is 5.1 at most.

I’d bet that people in the wider world who really need accurate manufacturer specs are not the ones chasing the most channels.

Rick “use cases, not just SOTA” Denney
 

Spkrdctr

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Time to go out and see the world.

Other than Africa and Americas the world has gigabit Internet and streaming is the major means to watch films.
It is always surprising how America comes late to the high tech stuff other countries have at least 5 years before we do. The chip credit cards I believe was a 10 year lag. Lots of other areas where we lag. In the really big picture I guess it doesn't matter but America has really fallen off of its world beating/leading perch from 20 years ago. Except for SpaceX and military equipment. We still lead in most, but not all military areas. In infrastructure we are way behind. But Americans like blowing things up more than building them. I'm guilty of that too.
 

mhardy6647

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Do like they used to do for car amps. Music power. 15,000 watts for a 1 microsecond burst, and yet it used a 5 amp fuse on 12 volts. Of course you'd have a completely useless spec.

I'd say .1% and if it cannot meet that 1% and if it cannot meet that just don't allow it.
One of the old jokes vis-a-vis some of the overly optimistic "ratings systems" would describe those as 15,000 watts ILS (If Lightning Strikes). :rolleyes:

I have no problem with 0.1% or 1%, as long as it is a hard line in the sand for consistency in rated, continuous output power specifications. Just pick a number that is in the realm of high fidelity and stick to it. It must be across the audible bandwidth- no cherry picking for the 1kHz 'test' only. Make it a requirement for advertising the product for sale in the US. And enforce it.

Obviously some amplifier designs clip hard and fast, others are more gradual- have a look at the latest little SMSL DA-6 class D @amirm just reviewed. 1% (-40dB) would take the power he arrived at into 4R from 30 to 50W and from 13 to 30W into 8R- a huge difference.
So... I mean, maybe it's just me... but the difference between 30 and 50 watts is 2.2 dB, and from 13 to 30 watts is 3.6 dB. Your concept of huge is rather different to mine. ;)

Except that lots of content, including old movies and not just music, are in stereo.
Some of the best movies ever made are in glorious mono. Some of those started as optical soundtracks, too.
 
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restorer-john

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So... I mean, maybe it's just me... but the difference between 30 and 50 watts is 2.2 dB, and from 13 to 30 watts is 3.6 dB. Your concept of huge is rather different to mine.

It's is indeed 2.2dBW and 3.6dBW. The difference of course is the voltage, running into the rails and clipping where the issues arise. This is what is ignored when simply eyeballing the 'knee' on a THD vs level plot and declaring a number which is based on a total THD that varies from one product to another...

Consistent, repeatable, accurate determination of power output and rated specifications is vital. So far with amplification, ASR is not providing a useful power output determination. With most other parameters, it's pretty good however. I sure hope the FTC either leaves the rule well alone, or makes a minor tweak in terms of advertised outputs for multichannel gear.

That little SMSL actually has what appears to be nice clipping behaviour.
 

Colonel7

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I have no idea what they mean by "the parameters of ...normal use..."
I'm thinking they'll assume no pre-outs are used for multichannel. All amps in the box are used...at least I hope so.

However, they could come up with something wonky like no more than 5 or LCR 3 amps driven only.
 

DonH56

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AVR = audio/video receiver = audio preamp, video decoder (to strip audio) and switcher, amplifiers
AVP = audio/video processor = audio preamp, video decoder and switcher, no amplifiers
Pre-pro = preamp-processor == AVP

HTH - Don
 

djtetei

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In my opinion, the FTC rule should be extended globally and lobbied in order to adopt an international standard where both average continous power and transient power should be clearly stated.
This will enable high quality amplifiers with good transient power (headroom) to stand out from the crowd.
 
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Spkrdctr

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It seems to me that the FTC is catering to the manufacturers. They started out three years ago thinking it would be a fairly easy update to the regulations. I believe they then received real, informed information from many in the audio field that wanted a very consumer friendly requirement to advance the regs to current technology. I believe they then realized they were kicking a hornets nest and now are going for round two with very meager goals. If they did follow the recommendations they received last time it would have been a nice jump in making units easy to compare to each other. At least in power specs and distortion. I am hoping for the best but since they are redoing the entire comment period with reduced goals, I am not expecting much.
 
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