Not sure if this topic had been discussed so I decided to ask. Is there any sound quality differences between running subwoofer with class AB and class D amplifiers?

If amplifier is rated 1x1050 @ 4 ohm @ 14.4 volt, does it mean if my current system voltage is only 13.4v, I get less than 1050watts? If yes, how do I boost the voltage to 14.4v?

Thanks again for the info...

I doubt anyone here can conclusively tell you that they know for sure that Class-D sounds any different to to Class-AB for sub bass. Some may try, though.

In so far as your amplifiers? Unless they are using stricly regulated power supplies - which is extremely rare nowadays, the amplifier will most certainly produce less power as input voltage sags. By how much is determined by a couple of factors, not least of which is the degree of regulation of the power supply. Also, the charging system itself will determine stability of output, and with 1000+WRMS you'll be drawing anywhere up to 1500-watts from your car's alternator/battery - which equates to over 110-amps maximum.

The brutal truth is that there is simply no need to be pedantic about ensuring your amp gets the full 14.4V. This is for a couple of reasons. For a start, devices like the Jacobs Accuvolt - which is a voltage stabilizing device that unsures a fixed level of output voltage regardless of input voltage - have thus far only made models that can support 100-amps. I have used these and can assure you that exceeding 100-amps is not advisable. When tested an SPL car with some a number of years ago (before we knew better) we blew nine of these $1,000+ devices in a nanosecond.

Secondly, even if output power of your amplifier sags by a couple of hundred watts between 14.4V and 13.4V, the audible output difference will be less than 1dB - which will effectively be inaudible.

So you are saying that i don't have to worry about voltage right??? Cool then... thanks for your info...

Not so long as it doesnt sag massively, no.

make sure you got thick cable
if you measure the voltage at the amp, under load (during SPL test) that will give you a better idea of what your power is likely to be

Thanks for your information, i'll do that sometime this week...

Have you considdered upgrading your alternator?
There are many different ones available on the market and I have seen them in up to 900amp capacity!
Google teh following brands for info on alternators.
HO Alternators
Ohio Generator
Powermaster
These are just a few of them.

For the alternator, how big do i need??? what capacity??? I use 2 ARC Audio 2500XXK and TruTech T03 4x150watts

also, class D is generally much more efficient than class AB, so more power, less heat

until you start clipping :mrgreen:

yes, well if you're clipping then you have other problems

Then, how is the sound quality of class D amplifier compare to class AB ampflier

exactly my point...

which brands / models of amplifiers are you comparing?

are you comparing the amps within, or outside the specified/recommended operating parameters?

are the amps under test both designed for the same type of application?
(you can buy class D full-range amps, and also class A/B sub amps)

in general, class D amps are more efficient and produce less heat for a given output power level

as to the sound - like anything, if it sounds good, then it's ok

so nyeah!
:roll:

what I meant was - there is no way to generalise that one class of amplifier operation sounds any better or worse than any other (except class C).

It all depends on which amps you are comparing.

Some amplifiers (Class A, A/B, D, T or whatever else) are better sounding than others.
Some amplifiers are good, and some are not so good

dunno how to explain...i think class a/b is better SQ...tat's why they only make class D for sub amp and never make class D for front amp

Dampening factor maybe?

i am comparing ARC Audio 2500XXK with Class D amplifier such as rockford and ARC Audio Class D... My interpretation is the Class AB is better for sound quality... better damping factor and should be more agressive than class D amplifier... the sub produce a tighter bass and more accurate... dunno if it is true or not...

I don't think most people could hear the difference, dampening factor goes to sh!t at low impedance anyway.
I remember the old Kenwood mono PS-401M amp had "sigma servo control" which was supposed to improve dampening factor.

I used to run my IDMAX with Xtant X1001d... and decided to try class AB amplifier to run my subwoofer... for me, i can tell the different with class AB amplifier... maybe it was just the psychological effect or maybe it is true... coz my installer said the same thing too...

with the filtering on the output of a Class D amp, it will not be able to play high frequencies, usually why they cut-off and 200Hz or so

a good class D amp will sound as good as a good class AB amp for subs
thing is, most class D amps are made for output power / SPL rather than SQ because it costs more to make the filters in a good class D amp

Yeah you cant realy say class D sounds worse than class AB as there will alkways be exceptions. The only thing you can say for sure is comparing 2 similar output amps the class D will draw less current/run cooler.

For SQ a huge amount of power really isnt needed so for many the class AB is a good choice, even thou it will draw more current, as the current draw isnt crazy, unlike SPL applications where more power and less current draw is half the battle.

PersonallY I think some of the latest class D amps have over come the issues that meant they often were not the best choice for SQ and so maybe an option, but I tend to go class AB when I build an SQ system as its far simpler from my POV. Going for what you know type deal. Its the same reason I dont use ported boxes. Sure I know I could, and would get great results, but for 3dB(which isnt an issue in SQ) and a lot of hard work I really just cbf bothering with ported. Sure you can get awesome low end output but in a cae with transfer function taken into account, why bother

Anyway the question is very hard to answer on a specific basis and as we all know generalisations wont do any good either
peace
Cyberpunky

Yes, Class A/B amplifiers are better at wetting the subs. They give more of a wet sound.

But class A/B vs Class D, it pretty much depends on the design of the amplifier. Class D amplifiers have a real efficiency advantage if they are only required to play a limited bandwidth (why some class D amps are only designed for subwoofers and do not cover the full range.

For SPL competition, Class D no longer have as much advantage, as (if you want to be as loud as possible) you tend to clip the amplifier to get as much power out of them as possible.

But these days, practically all manufacturers who produce Class D amplifiers (and Class A/B for that matter) are able to design them well enough so that they do not audibly colour the sound in most cases.

Its quite possible for a particular Class D to have a higher damping factor, less distortion etc compared to a particular Class A/B amplifier.

My understanding is class AB amplifier play widder frequency compare to the class D amplifier... certain frequency can't be played in the class D amplifier... so IMO, class AB amplifier is better than class D... eventho the class D amplifier has advantage in the efficiency...

i've used both class a/b and class d and i'll never use class d again!
even before the onset of clipping, bass hits sounded softer, less crisp.
at the onset of clipping there was no efficiency advantage

Correct me if i'm wrong, but i beleive there are many class D amplifiers that play full range... it depends on the switching frequencies For example, UDT are planning on releasing a 100wRMS x 4 class D fullrange amp about the size of a pack of cards Will be interesting to see how it performs

Alto Mobile already make them.
the switching frequency depicts the bandwidth, alto amps switch at 4 megahertz.

if you wanna experiment talk to "sonic nirvana" he might have a couple of 250WRMS ones for sale.

Xtant also make a full range class d amp. Its a very tiny (physical size) amp, with a switching speed over 1 mhz. It would be nice to have 6 of these for a 3 way setup.

101M I think it is?

http://www.caraudiomag.com/testreports/0308cae_xtant/

Just found out, its the Xtant 1.1i.

/me laughs at ultim8DTM5's sig.

:jump:

Haha I got sigs turned off and I had to go into my profile to see what you were on about, its good aye

Only if you are playing SPL test tones.

If you are playing music, then the class D will still have a significant efficiency advantage.

Whether this increased efficiency is needed or not is a different question.

One of the benefits of increased efficiency is smaller heatsink requirements (as mentioned).



This is basically correct - the added efficiency is at the cost of limited bandwidth. (some of the more advanced class D designs even alter the switching based on the signal to optimise efficiency..) But if the Class D can cover the required frequency range in a particular application without sigificant distortion, then does this technicality even matter? In the real world, provided the design of the amplifier is adequate for the application (in car audio it will normally be fine), then it doesn't matter.