class d and sq of subs, and mtx 1500dx

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Derek
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class d and sq of subs, and mtx 1500dx

Postby Derek » Fri Nov 12, 1999 3:34 am

i recently heard the thd is .403% on this amp. i'm looking to build a somewhat sq system, would this amp be okay? if i get this amp, (as you all know) it's going to be running two perfect twelves at 2 ohms. would it be okay, if i kept the gains down? and has anybody had problems with class d affecting sq of subs?

thanks guys.

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clay
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Postby clay » Fri Nov 12, 1999 8:19 am

class d amps are efficient but arent the best in the sq department. On subs it is a bit more okay. On speakers I just dont know. I think the distortion might be noticeable. Keeping the Class D on the subs should be okay though.
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jlaine
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Postby jlaine » Fri Nov 12, 1999 10:40 am

Strictly speaking subs you are fine, right now with the options out there you would be a fool to try and use a class D for anything else. They are pigs, put out a hell of alot of power, draw MUCH less than A/B hybrids, and run very cool. The distortion is yet to come under control yet, but you will not notice the distortion on the bass frequencies nearly as bad as you would the upper range. I would say go for it! I am running a class D to my Eclipse 8812.6 and I cannnot notice the distortion at all, even when I am pushing the amp to the limit. It is a life saver on your alternator also... In reality the only way you might notice the distortion is if you hook it up to a meter, I am very happy with my class D. Hope it helps, and good luck!
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cyberpunky
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Postby cyberpunky » Fri Nov 12, 1999 11:34 am

Class D design is only suitable for freq. up to 1000 Hz, as above this freq. switching noise can be heard. As stated in other posts, it has several advantages over class AB hybrids etc, notably 80% efficency versus less than 50%( less current/heat for same power). They make great Sub amps because of this, but are not intended for full range duties.
Distortion in sub bass region, unless excessive, is not readily descernable to humans, elephants may hear it, but SQ judges wont, so go for it.
Hope this Helps
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[This message has been edited by cyberpunky (edited 11-12-1999).]
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jlaine
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Postby jlaine » Fri Nov 12, 1999 1:57 pm

Earthquake's 200DHC mark 2...
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Derek
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Postby Derek » Fri Nov 12, 1999 2:56 pm

thanks guys, yep i'm just using it for subs. and jlaine what amp are you using?

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Phloodpants
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Postby Phloodpants » Fri Nov 12, 1999 9:31 pm

That high distortion rating on the MTX is probably just the distortion at full rated output.

My Infinity Beta 300 has a distortion of .2% at full rated output. 3% is the human threshold of perception, and that's at midrange frequencies. At bass frequencies, it's even harder to tell.

Infinity had some full range class D amps as well. I haven't heard them, but I can assure you, you won't hear any switching noise.

It all depends on how well it's designed. A switching amp that does well at high frequencies requires a high switching frequency. High switching frequency requires expensive transistors and other components.
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Postby jayb » Sat Nov 13, 1999 6:23 pm

speakers other than subs hooked up to a class d(most) sound like a vacumme cleaner is playing your tunes. really its not pretty one little bit. subs you really don't notice except for the low dampaning(sp) factor on some of them.

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Blues
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Postby Blues » Sat Nov 13, 1999 7:03 pm

I believe that the Infinity Beta 50 and 100 are/were full range capable. I haven't heard these newer versions on mids/highs but the ones produced several years ago sounded fine running the upper freq's. There was no apparent noise but there were not any audible benefits to them as opposed to other, less expensive class A/B's.

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