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Subwoofer Amps!

The amp topology used in subwoofers...does it matter? “It’s just a narrow frequency band, 10 hz to 100 hz at the most?”, one might say…. How could it matter all that much? “Well, that narrow band happens to be 3 octaves. In comparison, 10000 to 20000 hz is just 1 octave as far as human hearing is concerned...the subwoofer could be as equally important as the tweeter”, another one might say.

 

Recently, I went over to this guy’s house who is big into diy subs. I was in the process of selling him a class A/AB amp for his speakers actually. We were listening for a while and his subwoofer, though technically brilliant just wasn’t doing it for me. He had it hooked up to some crown amp. I said, “hold on a minute, let us put that amp you just bought for your speakers on the subwoofer instead!” .....and so we did, not so many watts at all, i.e., no thousands of class D garbanzo watts involved……….. And there it was...a holy cp moment, the sonic transformation that had occurred by merely hooking up this other amp to a subwoofer could not be overlooked.

 

For the longest time, I had wondered why the Rythmik F12G was a bit of a standout sub post-integration in terms of the amount of texture and discernible detail that it added to the music. I initially thought it had something to do with that GR research paper driver in use, but, I am starting to think it has also has to do with the class AB amp that Dr. Brian Ding uses for that model. More recently, I started playing with some German subs that sport Bash amps and was coming to a similar conclusion as well.

 

Dr. Hsu is on record stating years ago that he prefers class AB amps for the better damping factor in his subs...i think he’s gone class D since then... It is indeed a measurable parameter that one may think about, but, is there more to it that the measurement guys haven’t caught on to? I don’t know what to say…. But, if you’re a diy sub kinda guy, you may want to switch out your 1000s of class D watts with a space heater amp for a minute. You could be surprised.

deep_333

Showing 1 response by deep_333

deep_333 OP
1,743 posts
 

@phusis 

with the really important aspect here being using that same amp/its topology top to bottom - that is, over the main speakers as well. 

This seems to be my conclusion as well after a few years of pondering this...

 

Mind you: a 600W class A/B MC² Audio amp replaced a 30W class A Belles over +110dB sensitive MF/HF horns, and it was more than its equal. How’s that for the snooty, preconceived audiophile notion that pro oriented amps can’t sound great?

It is a good idea if the gems inside pro-audio remain a secret...The price of anything would just skyrocket if every audiophile found out about it (I certainly wouldn't want the "audiophile markup" on some gear).

 

Speaking of which: having audiophiles experimenting with different amps over their subs is not a prevalent subject nor a even a minor one on these pages, because when subs are used they’re almost exclusively acquired as all-in-one packages with built-in plate amps.

It’s a controversial subject even, treating the sub amp with the same care as you would the one used over the main speakers; 

I have thought about bringing up this topic in the past, but was mostly hesitant to do so because the anti-subjective/anti-experiential (anything) guys who spill into this forum from 'you know where' would probably start degrading the thread in a hurry.

I used to think that it was just relieving speaker woofers from the lower octaves with bass management was perhaps the reason for perception of any improved soundstage, improving fidelity of the upper octaves (upper bass, midrange, etc)...but, i suppose there's way more to it than that, i.e. the accuracy of low bass overtones and the psychoacoustic impact of it, impact on transient perception, etc.... which cannot be measured perhaps.... Michael Borresen got into this topic briefly on some video and i can't seem to track down which YT clip it was. 

If you’re working from a different platform though and include DIY, not least actively, you’re likely to treat the main speakers + subs as a single speaker system per channel, and not merely with passive main speakers that need subs (with different amps) to be "latched on" as an afterthought. This way you have the means and framework to find out about these things.

 agreed...

 

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