Axiom Home Page Forums General Discussion Technical Questions Using stereo receiver to run a subwoofer

Hello all..I am new to the forum and to Axiom. But after researching and reading a lot and with a little correspondence guidance from Alan, I will be buying an Axiom speaker system, most likely the M80's or M22's.

In either case I have a subwoofer I would like to use that is excellent but with a blown amp. The sub, which was manufactured by Speakerlab in Seattle, was specifically made for the emerging digital era circa 1979. Before I decide to either fix the amp (which I am now investigating) or buying an Axiom EP500 or perhaps not even using a sub at all if the bass response is good enough in the M80's (I listen to classical pretty exclusively) I would like to use my spare Denon receiver to run the subwoofer...it puts out around 55 watts per channel. I wonder if there is a way to hook up this amp to give the sub 110 watts and sync it to the other amp that will run the Axioms. This may save me some time and $ while I'm deciding. I have no idea if this is feasible. It may be better to buy a dedicated mono subwoofer amp on ebay or the like instead. I prefer not to spend much money while I am deciding. Any thoughts on how to do this would be appreciated...Cordially...Captain4105

First time I get to say WELCOME! I am new here myself. Please feel free to visit a thread I started and comment.

http://www.axiomaudio.com/boards/ubbthreads.php?ubb=showflat&Number=238133#Post238133

I'msure that you will get a lot of help from these great folks on this forum. The consensus seems to be that the M80's will put out plenty of bass and surely enough to keep you satisfied until you can solve your sub dilema. From my limited knowledge, which includes dabbling in PA Systems, I would think that even if you could manage to get both channels funnelled as one to your sub, that it wouldn't add a thing at 110 watts total to what you will be getting out of the M80's. Also subs have come a long way in 20 years. How many watts was the original amp in the sub and what is the speaker in the sub capable of handling?

My guess is that you would probably be best of saving any money that would be invested in that sub and put it towards a new sub.

I too, don't think it's likely that your old sub will add anything. Subs themselves have come quite a long way in this time...not just the amps. Your old sub likely doesn't go lower than 35Hz or so... which is about where the 80's will take you anyway.

Unless your classical tastes take you heavily into organ music, you likely won't feel the need for a sub at all as far as frequency response goes. If you like your peaks to be quite loud, a sub will take much of the burden off your receiver, though in the last few octaves.

How big is your room?

I like my M80s better when I run my sub with them, the low end has more feeling to it, not that it sounds bad with the M80s alone, the 80's produce alot of bass for a floorstander, just a personal preference.

I would suggest looking at buying a new sub over repairing the old one. As Mark said, new subs, IMO, are much better, they reach much lower and I think they play tighter and not as boomy as was the case 10-15 years ago.

Jay have you switched back and forth between 2.0 and 2.1 with music and noticed a difference? I find that, for the most part, I don't.

I agree with previous posters on the quality of drivers and power requirements. There is a reason that most commercial subs run on a minimum 350+ watts.

Yes Fred, I have switched back and forth and the PB13 adds a bit more to the low end, IMO, compared to the M80s set full range and no sub. It could have to do more with my limited placement abilities for the M80s, but like I said the m80s are very good on their own, just not as good as with the PB13 in my room, it might be different in another room. It could also be I like the ability to run the sub a little hot. I should try running the bass control 2 db hot and then go 2.0 to see if I like it as much.

Unless you run your sub flat its not an accurate comparison. It would be interesting to hear if running the sub flat changes the situation.

I would think that the M80s should keep up with a sub down to 40Hz, maybe a bit lower. I wonder though, at those frequencies, the drivers would be working a lot harder to produce sound than a larger sub driver, so you could end up with more distortion through the smaller driver.

Lee, another welcome. Some surgery would have to be performed on the sub to allow the output of the old Denon to be fed into the sub driver. Simply feeding the Denon output into the speaker terminals on the defunct sub amp wouldn't allow the power to get to the sub driver since the very high input impedance(tens of thousands of ohms)on the speaker level inputs of a sub prevents any appreciable power(just the signals)from getting through. Removing the sub amp so that you could connect the Denon directly to the speaker terminals on the sub driver might not be worth the bother.

Thanks John, that sounds about right...I was trying to salvage what I could that would be usable in building a new system. I'm inclined to start from square one....Lee

I have M60s (same woofers and nearly same bass response as M80s) in a 4000 cubic foot room with an SVS PC13-U. Formerly had a Hsu VTF-3.

The M60s have excellent bass, but a powerful sub adds considerable bottom end, even if the sub is calibrated to 0db vs the main speakers.

However this varies widely based on material. Much material has little content below about 40Hz. No matter how powerful the sub, if there's nothing there, you won't hear it.

Unfortunately producers often use slipshod mixing and mastering. This is more pronounced on the music side, vs the cinema side which has more uniform practices.

It's just trial and error whether your preferred music has much deep bass content. This in turn affects how much difference a sub would make.

It's really a sad situation. 25 years ago content producers could assume that consumers probably had limited bass handling. However all mainstream music content produced (or re-mastered) over the past five years SHOULD HAVE been monitored with robust contemporary speakers, generally including subwoofers and bass management. Unfortunately that's not the case.