Are all "clean" watts created equal?

[A.SMALL 17]

I will be starting another small build in my 530i soon and i'm trying to make good informed descisions on sub amps. I've been browsing different forums and reading different articles discussing topics like amplifier distortion and clipping.

Since i first got into car audio i have not ran anything but cheap budget systems. The amps i've used in the past 7 or 8 years on my subs have been : (excuse all of the weak sauce)

1. An old Concept cc-504a - ( i think 100 x 4 @ 4 ohms)

2. California Profile AP1000M ( 500 x 1 @ 2 ohms )

3. Kenwood 9103d ( 900 x 1 @ 2 ohms )

4. SPL DK2-2400 ( 540 x 2 @ 2ohms )

5. Kicker ZX 400.1 ( 400 x 1 @ 2 ohms)

6. Audiopipe AP 3000 ( 3000 x 1 @ 2 ohms )

7. Audiopipe AP 1500 ( 1500 x 1 @ 1 ohms )

and currently i'm using a crunch 600.2 amp rated 300 x 1 @ 4 ohms on a mmats juggernaut.

One recent trend that has seem to been buzzing on other forums is the whole "clean" vs "dirty" power threads. From what i understand the general meaning of clean power is power output at less than 1% THD and a un-clipped wave on an oscope.

One of the most hated brands in these discussions has been Audiopipe. Now don't get me wrong i'm not ignorant to the fact that there are better amps out there but for my specific application/budget they've been the best amps that " I " have owned. Most recently there was a bench test done by a guy named "Big D Wiz" on youtube. During the test he used a pretty stout power supply, o scope, the infamous dd-1, and a non-reactive load to test the output of a Audiopipe AP 1500.

I think he ended up getting about 1,100 "clean" watts out of it at a 1 ohm non-reactive load.

So my question is if two amps are set to put out the same 1,1000, or 1,000,000 "clean watts" and all other things are kept constant.......will they both sound the same (or at least unoticeably similar) or since one amps build quality is better sound quality will be improved over a cheaper amp?

[shizzzon 461]

wattage alone doesn't dictate how the output can effect projected SPL on a meter or audibly(which to me is debatable).

There are other things that go on or dont go on that should inside amps that will achieve greater SPL numbers on a meter. I cannot talk about audible differences because it would have to be extremely substantial.

IE - Very high damping factors vs extremely low damping factors can have an audible difference possibly.

IE - Non filtered outputs can create thermal issues with speakers quicker.

That's 2 things right there.

You have already narrowed down the rest, same THD level and same wattage comparison.

[Impious 1,476]

Power, gain, frequency response, distortion and noise are the ONLY things that impact how an amplifier "sounds". There must be not only an measurable but an audible difference in one of those items in order for one amplifier to sound different from another. That's it. Nothing else matters. Which means that if two amplifiers measure within inaudible tolerances in all 5 of those categories, they will sound identical. If two amplifiers "sound" different, it must be due to an audible difference in one of those 5 categories.

What Op amps are used, what caps are used, what solder is used, cheap or expensive.....none of this matters unless it audibly impacts one of the previously listed measurements.

It's a pretty trivial matter nowadays to build an amplifier with flat frequency response and inaudible levels of distortion and noise, so it's mainly going to come down to power and gain structure.

[Impious 1,476]

IE - Very high damping factors vs extremely low damping factors can have an audible difference possibly.

Damping Factor

Damping factor can be ignored in pretty much anything but true tube amps.

If there were an issue with damping factor, it would show up in a frequency response measurement (as listed above, must be in one of those 5 categories to audibly affect the sound). If there's no issues in the FR, then there's no issues with DF.

IE - Non filtered outputs can create thermal issues with speakers quicker.

How many car audio class D amplifiers are non-filtered? Even then I don't know if it thermals a speaker quicker since the inductance of the speaker filters out the higher frequency components.

[A.SMALL 17]

Presaite the replies,

regarding amplifier frequency response. Would a sub amp with the same power output from 20 Hz to wherever the low pass filter is set mean it has a flat response when compared to an amp that loses power output as the frequency decreases below the where the low-pass is set?

I think I've read a review where a lower quality amp started losing output power when measured below 40hz... could it be possible for a amp to put out 1000 watts at 50hz but only 500 at around 30??

[A.SMALL 17]

Well i found the answer to the question in my last post, pretty common sense answer idk why i even asked lol..

Wonder why manufactures don't publish the frequency response graph with amps like they do subs...

[Impious 1,476]

Probably because it doesn't take very much to build an amplifier with flat frequency response over the audible bandwidth. You basically have to intentionally build one that isn't.

[shizzzon 461]

thanks impious, got some random things answered for me.

About frequency response, you'll probably see this a LOT more with home audio than you will car audio.

You would have a receiver that states something like-

5hz - 20,000hz +/- 1dB

that means within that entire range, there will be a +/- 1db ripple.

Now, you may have +/- 3db, who knows..

I do not see these published on car audio amps or at least not any of the most recent popular ones. Probably because that spec is useless to most of us because most of us are just about getting loud rather than fighting sound quality response in a car.

And not talking about any particular brand here but if we were after sound quality response precisely, we probably wouldnt be using most of the common amps you see in builds today.

[Impious 1,476]

It's actually more likely that a "sound quality" amplifier would have a non-flat response....many of them probably get the signature "sound characteristics" ascribed to them by having some intentional frequency response anomalies to give them a subjectively pleasing sound.

For example, the RF Power T600-2 measured by CA&E had a boosted response from 20-200hz and 2khz - 15khz, IIRC it was nominally 2db but up to 4db on the low end with the crossover engaged. Was that an accident? Absolutely not. They did it intentionally. Think about it.....If you were to compare it to another amp on the sound board it would inherently sound louder.....and when you replaced your old amp with the new RF Power it would sound louder and "better" because they intentionally manipulated the frequency response. It's a forced, non-defeatable EQ built into the amplifier.

[///M5 2,833]

And 99 out of 100 times listeners pick the louder one on the board, not the better. Classic snake oil sales man trick is to play the more spendy units louder.

For clarity in case anyone else reads this thread. If ANYONE does a comparison with the DD-1 take it as a subjective test. That piece of gear is useless and anyone who trusts it is equally as useless when it comes to reviewing gear.

[Quentin Jarrell 671]

Around 2003 Mark Fukuda (with RTTI) at the time had a display board set up with a cheap radio shack head unit, a highend head unit, and a Rockford headunit hooked to a RF amp. All units were gain matched at low volume with an Audio Precision meter and the board had a switch to change sources. You couldn't tell the difference in quality if it was on the high dollar head unit or the cheap radio shack one.

[Quentin Jarrell 671]

And 99 out of 100 times listeners pick the louder one on the board, not the better. Classic snake oil sales man trick is to play the more spendy units louder.

For clarity in case anyone else reads this thread. If ANYONE does a comparison with the DD-1 take it as a subjective test. That piece of gear is useless and anyone who trusts it is equally as useless when it comes to reviewing gear.

I'd like to see Audio Precision test the DD-1. Just to see if the algorithm it uses works properly.

[///M5 2,833]

And 99 out of 100 times listeners pick the louder one on the board, not the better. Classic snake oil sales man trick is to play the more spendy units louder.

For clarity in case anyone else reads this thread. If ANYONE does a comparison with the DD-1 take it as a subjective test. That piece of gear is useless and anyone who trusts it is equally as useless when it comes to reviewing gear.

I'd like to see Audio Precision test the DD-1. Just to see if the algorithm it uses works properly.

It doesn't. Designer came on here. Wasn't the intent of the product.