class d and class a/b sub comparison

[Decipha 10+ year member]

a friend of mine has 2 kicker 10s in his truck powered by a shiity ma audio 800 watt amp (yea right) just for shiits and giggles i wanted to see how my rubicon would compare to his ma audio 800 even though his is a class d amp and mine is an a/b amp... well i swapped the amps and there was a very noticable difference. Even him who doesn't have what i would call an 'ear' for music, could tell the difference. It sounded much more dynamic and more life-like. I know class d amps are used for bass since they are more effecient.. but how come people don't run class a/b amps... im die'n to get my hands on one to try out on my 15s.

any thoughts??

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[Twistid 5,000+ posts]

shut up

 

[bigwheel15 10+ year member]

I use a class a/b amp for my sub. //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[JimJ 5,000+ posts]

Did you guys use a clamp meter to make sure both amps were at the same power level, and an o'scope to verify that they weren't clipping?

You heard what you heard, but I'm just saying that your experience isn't valid for anyone else reading.

 

[jdawg 5,000+ posts]

I use class a/b

 

[BMW Sidewayz 10+ year member]

I seriously dont know why some people take the time out to re-ply to a post in the most rude ways. The Admin should do something about this. The purpose of this forum is for people to share and dicuss things about car audio, and of course there will be people to ask questions that dont make sence to others and its obious, some of us have more knowledge than others. Anyways.....

Class D amps are highly efficient producing only a range of frequencies for sub bass instead of covering a wide spectrum of freqs. It specialises on a set of frequencies. Im pretty sure theres other things that contribute to the facts. Here are some links that can help you understand more.

http://www.geocities.com/phatcow2/TClassExplained.html

http://stereophile.com/solidpoweramps/805cia/

http://www.teamrocs.com/technical/pages/classd.htm

http://www.audioholics.com/education/amplifier-technology/the-truth-about-digital-class-d-amplifiers

http://en.wikipedia.org/wiki/Electronic_amplifier

http://www.eaamps.com/2005/technology/classd.htm

http://stereophile.com/solidpoweramps/805cia/

Im going to be doing some reading myself! MORE INPUT, MORE!, mORE, MORE!!!

 

[helotaxi 5,000+ posts]

This exact topic was discussed ad nauseum about 2-3 weeks ago. You won't hear the difference 99% of the time and the a/b amp is hugely inefficient by comparison.

 

[thch 10+ year member]

a friend of mine has 2 kicker 10s in his truck powered by a shiity ma audio 800 watt amp (yea right) just for shiits and giggles i wanted to see how my rubicon would compare to his ma audio 800 even though his is a class d amp and mine is an a/b amp... well i swapped the amps and there was a very noticable difference. Even him who doesn't have what i would call an 'ear' for music, could tell the difference. It sounded much more dynamic and more life-like. I know class d amps are used for bass since they are more effecient.. but how come people don't run class a/b amps... im die'n to get my hands on one to try out on my 15s.
any thoughts??

I've had the same experience, twice, and with conflicts.

I switched from a class D amp to a class AB amp. things sounded better. the bass had better attack and sounded better, all that jazz. a large class AB amp is not efficient, especially when run below rated power, and I grew sick of the dimming it caused. (light dimming even on moderate volumes) so I switched back to the class D amp. suddenly the music was once again clearer and had a crisp, defined quality to it.

of course, my goal each time was not to prove one amp sounded better then another. My goal was to acheive good sound. in both cases, the re-setting of gains, crossover, EQ, and other settings was done. Further, I don't always listen to the music I prefer to set my car up with. so the test was clearly not scientific.

 

[squeak9798 5,000+ posts]

Class D amps are highly efficient producing only a range of frequencies for sub bass instead of covering a wide spectrum of freqs. It specialises on a set of frequencies.

Utterly false.

Class D has been capable of satisfactorily reproducing 20hz-20khz for over a decade.

As to the OP; Helotaxi & JimJ pretty much covered it.

Your comparison is completely invalid in trying to assess the tonal qualities of amplifier classes. All you really showed is that two amplifiers of different power levels setup differently will result in a different sound. For some reason people believe that simply removing amp A and installing amp B constitutes a fair or valid comparison....which isn't the case.

 

[BMW Sidewayz 10+ year member]

Utterly false.
Class D has been capable of satisfactorily reproducing 20hz-20khz for over a decade.

As to the OP; Helotaxi & JimJ pretty much covered it.

Your comparison is completely invalid in trying to assess the tonal qualities of amplifier classes. All you really showed is that two amplifiers of different power levels setup differently will result in a different sound. For some reason people believe that simply removing amp A and installing amp B constitutes a fair or valid comparison....which isn't the case.

Yeah, my mistake. I usually dont like to guess, thats why I stated that I was going to doing some reading of my own, but thanks anyways. A new thing learned.

 

[BLD 25 10+ year member]

I had a soundstream rubicon 1000-2, and it did sound beautiful, but i looked like a police car at night since my lights were flashing. Expense, and inefficiency are reasons people don't run high power A/b for subs.

 

[Blazemore 10+ year member]

Expense, and inefficiency are reasons people don't run high power A/b for subs.

In an SPL yes but in an SQ environment I'd use A/B for low distortion, better damping, decent efficiency, and dynamics control.

 

[luvinthebass 5,000+ posts]

In an SPL yes but in an SQ environment I'd use A/B for low distortion, better damping, decent efficiency, and more dynamics control.

It's all in the install, my class D amp that i have was more efficient in the 40-50 hz range, seemed to be it's sweet spot.

 

[Blazemore 10+ year member]

It's all in the install, my class D amp that i have was more efficient in the 40-50 hz range, seemed to be it's sweet spot.

Might be more efficient, but at the cost of pure audiophile performance. Leaving it at that.

 

[helotaxi 5,000+ posts]

Might be more efficient, but at the cost of pure audiophile performance. Leaving it at that.

In the sub bass range I doubt you could tell the difference. THD can easily be the same between the two topologies. Damping is a non issue until you get down into the tube amp range. A/B efficiency is at its worst at mid volume, the neighborhood of 30% or lower is not really uncommon. Dynamic control...right...//content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif