What is better for running subs, Class A/B, or Class D?

[Eric D]

Since the passive vs active debate is going strong and has brought up some great information, I figured I better bring this debate up as well.

I personally have always been a fan of Class A/B on subs, but recently have changed my attitude and now believe Class D is the only way to go. So what do you believe, and why?

[todd217]

im a fan of a/b. i think that the a/b sound cleaner. i have only tried a x600.1 with class d. im older and more or less grew up with a/b and maybe i have not givin the a fair shot.

[Stryker]

I liked my old 400Ti and the 600ti on my 15`s.... sound was great but they (ab amps) are so power hungry. I like the d-class for the fact that they use far less power. i can`t tell the difference really, I`m sure if there were exact same setups side by side with like amps in ab and d then perhaps a small difference could be heard. If given no charging issue`s and amperage draw was not a factor I would probably still stay with D class just cause the footprint seems to be smaller in most cases. They also tend to offer more wattage. just my .02

[smgreen20]

I hear no real difference between the two, so I really couldn't say one way or the other. I think that if I had to choose, I'd pick D.

Why? More efficient, and at those freqs we really can't hear distortion.
Those are my 2 reasons, my 2 cents.

[shawn k]

Since the passive vs active debate is going strong and has brought up some great information, I figured I better bring this debate up as well.

I personally have always been a fan of Class A/B on subs, but recently have changed my attitude and now believe Class D is the only way to go. So what do you believe, and why?

OOO I like this one

So why have you changed your mind? Why is D the way to go you need to explain as well

[Eric D]

I now like Class D due to efficiency.

Assuming 90% on a power supply, and 50% at best output section in a Class A/B amp, a similarly constructed Class D amp with a 90% power supply and 90% output section has about twice the power capacity.

With that much extra power you can afford to throw some way.

I don't think a flat response Class D amp exists. Part of the technology makes for a bad frequency response. My assumption is this is why a lot of people don't like the sound of a Class D amp. If so, I have to agree with them.

So, use an EQ to CUT the peaks in the Class D response, and you are left with an amp which will sound the same as a Class A/B (we are taking bass here, with plenty of breathing room distortion wise), draws much less power off your electrical system, which could be harming the acoustics of the amp running your components, and likely takes up a lot less space.

[rocafella1]

in my experience class d is better for spl and can take more of beating than a a/b class amp

[wash with gasoline]

I have been of the opinion that class d sucks since i bought a tantrum 1200.1 and ab tested it with a zx600ti and a ms2125 on 2 ti12's in sealed boxes

The 1200.1 had way more power but it just sounded muddy to me, i returned it the next day and got another ti600

I will try another class d out sooner or later, but im still a class a/b guy for now

What frequencys do you have to cut to make them sound good , or is it diff on every amp?

[Eric D]

Different on every amp, and likely different depending on the load you are running.

From what I have read a large portion of the audio quality of a Class D amp is the quality of the filter used to bring its PWM (pulse width modulation) output back to analog music land.

Also, the tantrum 1200.1 is kind of "primitive" by today's standards. It uses "tripath" what ever that means (never really looked into it myself). I am guessing it is somewhat hybrid like Rockford's Class BD technology. But, none of this means you would have any better luck with a Xenon 1200.1 for example.

I big portion of my new found excitement for Class D stems from the testing I did with the S1000.1. I was shocked by how much it spanked the very large Class A/B amps we replaced with it.

I am curious how you did your AB testing on it. How did you power both amps and give them a signal at the same time? What model DMM did you use to match their outputs, and what frequency (frequencies) did you do the gain matching at?

[wash with gasoline]

It wasnt all that scientific

I had a pioneer dex p1r head unit, used the built in xover

1gauge power cable, i just used a power distro and had power hooked up to 2 amps at once

I left my head unit turned 3/4 of the way up with no eq on and just switched rca and speaker wires (turned it off while i switched) listened to some rock, rap, and electronica that i was familiar with at the time

I just turned the gains up until it blended with my front stage, the ms and ti amps both sounded great. The tantrum 1200.1 sounded great with the one note rap bass, but on rock the bass guitar and double bass drums had no definition. It was just lots of muddy rumble

Of course i played with it a little and cranked the gains up on some rap music for fun, and it had a ton of power. But i listen to everything...

I ended up going with the ti amp because i liked having the bass boost knob to use, and it had great sq

This was all when the tantrums first came out, i didnt know how to use a dmm to set gains yet

I had a tube driver 4 channel running vifa mids and tweets up front and some infinity 4x6 plates for rear fill ...I dont bother with rear fill anymore either

[Eric D]

Well, it was probably scientific enough to prove the Tantrum did not do what you wanted it to do, and that is all that mattered.

[rscecil007]

Eric,

If you were close I'd let you test/play around with my JL HD amp.

I may get banned for owning it, but I've very happy with it. Stupidly small, doesn't even think if getting hot, and is dead quiet noise wise.

[kg1961]

talking about jl amp I have 2 slashv1 amp 300/4 and 300/2nib
Im going to use them both class a/b in my set up
the 300/4 just doesn't have the power i need for my 15" sub so im going to run the 300/2 to the focal.(picked uit up nib for 80 cnd)
In my wifes car she has the 500/1v1 class d so i can switch them to see what i like more. they are the same size,smae 50amp small fuse size but the a/b will get 300-375 power were the class d hits 500-600 watts rms.
The only thing i like and dis like about the jl amp is the R.I.P.S power
I like it because you get the same clean power from 11volts to 15 and 1.5ohm to 8 ohm stereo. but i don't like the a/b amp can only be bridged down to 3 ohm not 2 ??? but this is why they make the class d same power form 1.5 -8.
I know most of you on the forum love pg and i do to but i have to say I like the sound and xover on the jl better. I got all 3 of mine new for $700 in total and they are just as strong as zx,ti amps....if used right
I have gone back to them as they never get hot sound great look good not cheap. As most of you know i have own most of the pg amps. the only one that came close was the reactor but the size was and is a little to big and power hungry.

[Eric D]

Eric,

If you were close I'd let you test/play around with my JL HD amp.

I may get banned for owning it, but I've very happy with it. Stupidly small, doesn't even think if getting hot, and is dead quiet noise wise.

I really want to try one myself. I am curious how good full range Class D sounds, and I love the clean look of those amps.

[smgreen20]

To each his own, but to me they're just another overpriced piece from JL. I was amazed at how small and clean they are/look.

[kg1961]

i have to say i am very very happy with the slash v1 jl amp clean cheap to buy easy to use very very good xover and not power hungry

i love the sound of my focal kx38spl sub its low like a 15" but punchy like a good 10
its only 300 watt rms but i feel class a/b make it sound or work better
i like the jl 500/1 it get loud but less control? maybe it just the sub but i love it so far

[denim]

The technology on Class-D amps have really improved over the years. I am a little old school in that I prefer my amps to be A/B, but as these Class-D amps get smaller and smaller and I know I cannot hear a difference, it is hard to cling to my surfboards.

[12voltjunky]

I have always used class a/b amps for sub duty but am considering giving the class d a chance in the near future. I like to run a lot of watts and do not want to upgrade my alternator so it would make sense for me.

[jbob0124]

I personally liked my tantrum 1200 to my 12's better then the zpa.3 I had hooked up to them, but in the zpa's defense, I never gave it the full potential either. I would ultimately choose an a/b over a d though because I like having the quality vs. the power of it. Although the class d prices generally are much cheaper.

[kg1961]

i have tried both my a/b jl 300/2 vs my D jl 500/1 i would say same shit differnt pile. I can't here or see any differnce other than getting 200 watt rms more out of the class d. same size same amount of power need to run them
I don't need the extra power to it will stay in the wifes car

[shawn k]

So far I'm still sticking with a/b. I prefer the a/b over D for it's sonics. There are a lot of benefits for going class D like effeciency and typically having a physically smaller footprint, as previously mentioned. Fortunately for me I'm not the type of guy who usually listens to his system at high volume, negating the need for high current demands. Nor do I worry about installing "average" sized a/b amplifiers. This affords me the ability to stick with my beloved a/b's untill I'm one day finally impressed with the sonics of a D.

[Pillow]

How timely.

Next week I will be switching out my ZX500 for an equally old school MMATS D200HC (1400 at 1 Ohm class D). Switching the Brahma from 4 Ohm to 1 Ohm configuration.

I only run a single 15, so it needs to wang.

The ZX500 does an excellent job, but I think these days it would be better matched to a set of components and leave the D class for the subs.

D class power is just so inexpensive with insane outputs! Yes, on paper it is not as clean power as A/B, I bet I cannot tell.

[12voltjunky]

Anyone tried an AQ2200 class d amp

[ttocs]

I have two vehicles, both with class a/b amps running the subs and I am happy with them. I have never done a class a/b comparison but it makes me wonder if I would notice as long as each amp was set up correctly.....

[dwnrodeo]

I am running A/B for sub duty in my winter beater/dd and class D in my summer car and I think they both sound good. Obviously there are too many variables to make a fair comparison between the two, but I think class D for sub duty sounds fine. It plays such a narrow portion of the audible frequency spectrum (20hz-80hz), that I can't see why class D wouldn't sound good in my setup.