SQ sub: Defeating the purpose by using a class D amp?


Silver Member
Username: Phuktupbasshead

Scottsdale, Arizona United State...

Post Number: 197
Registered: May-05
I was just wondering... I own a class D mono amp. I'm looking for the best SQL sub for my situation - then, suddently it dawned on me!!!
Is a class D amp and an SQ or SQL sub NOT a good match. I mean, to be a musical sub, I would need an A/B amp, right? Please help me straighten this out in my head. If I'm gonna keep the class D, should I not even bother with SQ factors, or is that just wrong?
Thanks, everyone.

Gold Member
Username: Jonathan_f


Post Number: 4425
Registered: May-04
The subwoofer makes far more difference than the amplifier does in sound quality. You'd be cheating yourself if you didn't get a good SQ subwoofer solely because you have a class D amplifier. A/B is superior to Class D in specs, but side to side, especially in a car, you won't hear the difference between the two unless they are in a state of clipping.

Mikey H
Unregistered guest
Also, class D are specifically meant for subs, they are more efficient at higher power and will run cooler=last longer

Silver Member
Username: Zero43

Kyle, TX USA

Post Number: 131
Registered: May-05
It was told to me that below 100hz Class AB and D have no noticeable difference in sound quality

Silver Member
Username: Basshead86

Ocala, FL USA

Post Number: 482
Registered: Aug-05
another answer from GlassWolf to clear up any confusion


umm actually class D amplifiers are only for subs because they can't switch fast enough in the "on/off" state of the transistors to produce a clean signal that's audibly acceptable above subwoofer frequencies. Any frequency higher than about 200Hz, and the distortion and lousy sound quality becomes audible.
Class D amplifiers are more efficient, and thus run cooler with a smaller footprint as well so yes, they are well suited to high power applications for subs.


Silver Member
Username: Phuktupbasshead

Scottsdale, Arizona United State...

Post Number: 203
Registered: May-05
I was under the impression that a class D only amplifed the bass frequencies, and that an sq or sql sub was capable of musically producing other frequencies as well. thus, the class D would be depriving an sq or sql sub of some of the frequencies that it actually WOULD be able to reproduce nicely.

I was wrong, or right? (It makes so much sense, you know.) Please clarify again for me. Sorry, but I appreciate it. Please clarify.

some subs go up to 400hz and some 20khz but you wont have to go any higher then 200hz because your mids should be set at 120hz or 160hz anyways

i have my subs set at 200hz with no complaints

Silver Member
Username: Zero43

Kyle, TX USA

Post Number: 144
Registered: May-05
all amps amplify all signals received which is also why you can hear noise through the sub. A d class is just better used for sub frequencies and AB can be used for all

Gold Member
Username: Glasswolf

Wisteria, Lane USA

Post Number: 9256
Registered: Dec-03
200Hz isn't a sub anymore.. it's a woofer or midbass driver at that point.
it's also boomy and you're getting into the range that you'll get issues with cone resonance at those frequencies with subs larger than about an 8"

as for amplifier class, remember a speaker actually generates more distortion than an amplifier could think of making, so in reality you won't notice any real difference with a class D amp on your subs, audibly.

if you want to know more about amplifiers, read this page;
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