What are your opinions on the importance of the quality of the sub amp when it come to sq??

If you've got a nice sub, eg. IDMAX, utopia, etc,
how much value do you put on the quality of the amp. Is power more important than sound quality of amp. (lets not get into the amplifier is an amplifier and shouldnt change the sound debate)

Eg, is there an advantage of spending the extra money for say, a PG titanium over the a tantrum
Or a Vrx over the lrx, or just go for the most power you can get for your money.

I hope ive explained this ok and you can understand what im saying.

Any way, what do you think, and opinions/help would be greatly appreciated.

Cheers
Tim

there's definitely difference between amps when it comes to driving difficult loads like subs. it's a demanding job for any amp, requiring lots of power, and the ability to maintain that power during demanding subbass passages of music.

equally important is your power supply to the amp, so take this into consideration.

typically, a monobloc of the same power as a bridged multichannel (eg: 2-channel amp) is far better at driving subs. monoblocs are usually designed around a phat internal power supply and lots more internal 'stiffening caps'. as such, they more easily maintain power output to the sub, arguably making for better dynamics.

some subamps will also feature useful features like steeper xovers and subsonic filter.

i have only ever owned the one monobloc, the audison VRx1.500. it's stable to 1ohm which may suit some peoples' needs (although i run it at 4ohm). definitely a better amp than my previous alpine 2-channel, but not a fair comparison for reasons of both price and power output.

between different monoblocs, there's probably less of an SQ difference. and i would expect most amps at a similar price point to offer similar performance.

between different series of amps? not sure. for audison, the VRx offers more power cf the LRx monobloc (but SQ is probably the same). is this similar between the PG amps (no idea)?

you local retailer may be able to help you here. but i'd be skeptical of any significant SQ differences between different series amps of PG, audison, etc.

good luck

Also remember if you bridge an amplifier, you lose efficiency. So a 2 channel bridged into one, may output more watts RMS than a single monoblock. However you're still losing out because the bridged mode forces the amp to work harder ie less efficiently.

In basic terms mono's create power with less work. Better for SQ.

Not neccesarily, it depends on the design of the amplifier.. Monoblocks are not automatically more efficient than bridged amplifiers. However, some (not all) monoblocks do gain efficiency by using a Class D output stage. (Obviously, you can also get bridged class D designs...)

Also, this is getting a little off topic, but basically transistors are most efficient when they are either off, or fully on (saturated). The more power the amplifier is putting out, the closer the transistors will be to saturation so amplifiers (with linear output stages, ie Class A, B, A/B etc) typically are the most efficient at full power (ie when clipped). Class D amplifiers are designed with this in mind, so the transistors are operated in switch mode, rather than in linear mode. The idea is to switch the transistors as slow as possible, but without the switching causing audible distortion. This is typically why Class D amplifiers are used for powering subwoofers, because by restricting the bandwidth to lower frequencies, the switching speed can be much slower without causing audible distortion, thus gaining efficiency. As you may have worked out, much of the efficiency gained by a Class D amplifier occurs at less than full volume - once you start clipping a Class A/B amplifier hard, the efficiency becomes similar to a Class D amplifier at full volume.

[ December 29, 2003, 00:04: Message edited by: Bassaholic ]