Question re: subwoofer amps

Early B.

It is generally agreed that higher quality amps produce better sound on two-channel systems, right? OK, so does this hold true for woofers as well? In other words, will a $100 200 watt Parts Express plate amp sound just as good as a sub powered by a 200 watt Outlaw monoblock or bridged Parasound/Rotel?

Similarly, do some plate amps sound better than others? What do you look for in a high quality plate amp?

Just curious. Thanks.

goingganzo

power and what you want in it like s ss filter eq or a phase ajustment.
i like pro amps you can get them for a littel more than a good plate amp but you get alot more power. like 2400 wats rms for 300 bucks

labrat

2400 wats rms? Hmmm.... If you take wats/volts you get amps - so 2400wats/120v = 20 amps. That is just the output, you would need more than that for input. Do you have to go to a 220V circuit just to keep the amperage in line?

Having noted the above I really doubt you could stand that kind of power for more than an instant - so power consumption probably isn't an issue.

Excuse the drool on the screen - thinking of that kind of power in a sub has that effect on me. Where do you find such amps? Does having that much raw power on tap degrade the signal (sound) quality? Do you use the x-over built into the AVR or use an external? And what do you drive with such an amp, a dozen 15 inchers or something;)? I am seeing either sealed boxes or an IB system.

Thanks for giving us another sub option,

labrat

jdhdiggs

Originally posted by labrat
2400 wats rms? Hmmm.... If you take wats/volts you get amps - so 2400wats/120v = 20 amps. That is just the output, you would need more than that for input.

This is why I have a dedicated 30 amp line being put into the basement with two dedicated 20 amp lines. (All for the HT)

PolkThug

What matters is does the cheaper amp REALLY measure up. Meaning, how was the 200watt rating attained and at what ohms.

jdhdiggs

If it is an amp (not reciever) it must be able to meet the published specs by law. How much headroom and quality, well thats a different story.

McLoki

I think driving a sub would take as much power and control as driving any other speaker in your system. It is a much overlooked area imo. Alot of any power can play loud, but it takes quality to get control (and good sound).

I have no idea how my sub sounds compared to a 25-31 PC+ but I know that my 25-31 CS+ sounds awesome with killer control over the woofer and integrates very well with my LSi speakers.

Michael

(I do still plan to replace it with a CS-Ultra someday, just because awesome is never quite good enough.... )

PolkThug

Originally posted by jdhdiggs
If it is an amp (not reciever) it must be able to meet the published specs by law. How much headroom and quality, well thats a different story.

Wish they would do that with receivers, I get tired of explaining that the "770 watt Sony" is not really more powerfull than the "600 watt HK/Onk".

Early B.

Still looking for an answer to my initial question re: amp quality with subs. Does it matter? I would imagine that it does, but have no real experience to back it up. If my SVS PB12 were powered by a bridged Rotel pushing out 360 watts, would it sound better than their standard plate amp?

McLoki

Originally posted by Early B.
If my SVS PB12 were powered by a bridged Rotel pushing out 360 watts, would it sound better than their standard plate amp?

I would guess that it would not go quite as loud. (I think the PB-12 has a 500 watt amp) but I would expect more control and better bass.

I am guessing the reason that most people put cheaper amps on subs is because with most car crashes/cannon blasts, you are looking for impact rather than finesse.

If you are running the sub in a 2 channel or more music system with speakers crossed over at 80hz or so (so the sub actually has something to do), I would expect the better amp to really shine and be very noticable.

Michael

jdhdiggs

Yes, it does make a difference. However, our hearing is less sensitive at those frequencies so it isn't as apperent. For <80Hz, I would look at power, slew rate, and damping factor as prime interests for the sub amp. Mosy sand amps will have good THD numbers so no worry on that.

My suggestion would be to use WinISD and figure out at what power/frequency will your sub bottom and then by the highest quality amp you can that has enough power to bottom the driver ABOVE the tune point.

On a sub amp, I don't care how delicate it is if it can't produce the dynamics. This is one case where power is more important than finesse. (within reason of course) IMHO

Early B.

Thanks, fellas. Makes sense.

brody05

I am running a sub with an NAD 218 (1200 watts at 2 ohms) and yes a good amp makes a noticable improvement. It is not just volume but the responsiveness and ability to handel the big loads the lower freqs require.

I am not the only one, POLKWANNABIE has changed his SRT sub amps and got good gains, there is no doubt others.

The biggest benefit for me personally is the fact that I have more control over the low pass filter allowing the sub to handel dips in load of down to 1 ohm without having a hernia, not many 'normal' sub amps out there handeling that. Like any speaker a sub sounds a lot better with better quality power.

In regards to the hearing, your ears have the ability to distinguish low freqs as well as tactile recepters throughout the body, it isn't hard to tell the diff between 20 hz and 30hz, not to mention other freq ranges.

PolkWannabie

The original SRT subs have 300 wpc plate amps which sound decent but there is no comparison to what they sound like with a conservatively rated 600 wpc CinePro. Cleaner, tighter ... well worth the trip.

Whadyasay

I think that amp quality for subs is very important. Very low frequencies require quite a bit of power, and clean power at that. A good amp should be able to provide that kind of power without working too hard, and be able to do it continuously and quickly. I don't think you would notice tonal differences as much as overall performance differences with sub frequencies. Bad amps can make the sound muddy and low in amplitude, or make the bass sound slow and sluggish, or disturbingly rumbly because of distortion in the amp.