Axiom Home Page Forums General Discussion Advice from Axiom Owners Advice on a Subwoofer power rating

I've had my M3s for 5 years now and continue to enjoy them to the hilt. I felt it was time to add a little more lower end bass and have decided to purchase the Polk Audio PSW10 powered sub. Its economical and has all the features found in larger powered Subs. The sound too is agreeable to me although I may have liked a lower extension in a sealed sub.

However, this is where my confusion begins. My amp is a 50W x 2 custom made product which plays clean down to 4 ohm impedances. The PSW10 is however a 50W RMS rated sub amp. My plan was to hook up the speaker inputs into the sub and crossover only the high frequencies to my speakers thereby possibly allowing them to play cleaner with the sub taking on the entire burden of playing the bass.

I would like to know whether this is possible. If I hook up the speaker level into the sub, would this be 100W or 50W going in? Can the sub amp handle this power? If not, I will be forced to use the RCA (line level) inputs on the sub from my amp.

Any advice would be greatly appreciated.

Many thanks

Shankar, hello again. When we were discussing subs a couple of years ago I recall that the unusual method that you were going to employ to get it into India made small size a key factor. From that standpoint the PSW10 qualifies, if size is still critical, but depending on how you're actually going to get it, there may be other choices that should be considered. For one thing, the speaker level outputs on the PSW10 are simply a straight-through full-range feed; there's no high-pass filter to roll off the low frequency response from your M3s, so there wouldn't be any advantage in using that type of connection if you have a line level output from your amp available.

If you did make the speaker level connection it would simply feed your 2x50 watt outputs straight through to the M3s and wouldn't affect the internal sub amp in any way other than to feed the audio signals into it. Because of the very high input impedance of the sub amp(in the tens of thousands of ohms)essentially no power from your amplifier would get into the sub amp, just the audio signals. Let us know if you have other possibilities.

Hello John. My compliments your amazing memory recall of our earlier conversation. It is ironical that you were the first to reply to my post because I did want to PM you this very same message yesterday and then decided to post it on the public forum.

I do not have the issue of innovating anymore to bring the Sub to India. There are a couple of stores here that now stock everything from Velodyne, KEF, Paradigm, Polk, Bose, Denon, Marantz, Klipsch etc. The range available is plenty but the PSW10 is the only one retailing at INR 10700 (US $243).

I've just had another look at the PSW10 manual. I now understand what you're saying. There is no high pass crossover on the sub. Only a low pass crossover. So this would imply that I need to connect my Speaker A outputs from the amp to the M3s and the Speaker B outputs to the sub speaker input.

Or, I can connect the Speaker A to the M3s and the line level output to the line level inputs on the sub and adjust the crossover.

Please let me know if I've understood the above correctly.

Thank you

Yes, your understanding is correct; the low pass crossover in the sub would affect only the sub itself, rolling it off above the set frequency(which marking typically may not be very accurate)and not affecting the speakers in any way, even if they were connected through the sub. Since you have both A and B speaker terminals on your amp, the most convenient hookup would probably be to use speaker wires from them to the speakers and sub, without bothering with the line level output.

So, if rupees available match the PSW10, obviously that's the way to go. Enjoy.