Axiom Home Page Forums General Discussion Home Theater Expecting more output from sub.

Real quick, here's what I have.
My receiver is a Denon AVR1802. My subwoofer is a Polk Audio PSW450.

Specs for Receiver: http://www.usa.denon.com/catalog/pdfs/avr18023.pdf

Specs for Sub:
http://www.polkaudio.com/home/specs.php?recent=1&category=7&speaker=49


Now, let me start by stating that the subwoofer is connected by a high-performance rca cable, using lfe. First and foremost, do I still need to connect the speakers to the sub, or can I just use the lfe input alone? ;-)

The main problem is that I have the volume, on the subwoofer, all the way up, and the output levels on my receiver set to +11 (+12 is max). And I'm really not getting a whole lot of boom out of the thing. Opinions, tips, ideas. I'd appreciate any of 'em.

Thanx.

You should absolutely use the LFE alone. Do not hook up the speakers to the sub unless you're using the low pass speaker inputs into the sub.

Can't really speak to the second item.

Tim as long as the sub cable is a shielded coaxial cable with an RCA connector on each end no special attention to quality is necessary there. Then I assume you have the cable running from the sub out on the 1802 to the LFE input on the sub, which is the correct input to bypass the sub crossover and rely on the 1802 crossover, which should be set at 80hz, with all speakers set "small". The speakers would be connected with regular speaker wire to their respective terminals on the 1802 and wouldn't be connected to the sub at all. If you mean that you have both the 450's own level control and the sub level adjustment on the 1802 practically all the way up and yet aren't getting much bass(note that you shouldn't be looking for a "whole lot of boom"; the sub isn't supposed to be heard separately, instead the impression should be that the other speakers are putting out more bass), then either the sub amp is defective or the 1802 sub out isn't putting out enough voltage. As a test, use the alternate connection method with speaker wires from the 1802's regular main terminals to the high level speaker input terminals on the 450. Report if there's a decided difference when the sub out on the 1802 isn't used.

I appreciate your reply and will test your instructions.

If the high-pass sounds better than the lfe, what would that tell you? Is this good or bad? I thought low-frequency was better? Would this prove that the receiver isn't outputting high enough?

Thanx.

Yes Tim, using the coaxial cable from the sub out to the LFE input is generally better. I'm just suggesting as a temporary test measure that you connect speaker wire to the speaker level sub inputs instead. If you then get plenty of volume from the sub that indicates that the sub amp is okay, but that the sub out on the 1802 isn't working right or possibly that the LFE input on the 450 has a problem.

I should add that when you use this alternate connection, you have to set the mains "large" and the sub no in order for the bass to be output from the main terminals instead of the sub out on the 1802. Your owners manuals explain this connection and receiver settings.

Ken,

A couple of things to double-check:

(1) The crossover frequency knob on the sub should be all the way up. If the sub has a switch to defeat/engage the crossover circuit, then it should be defeated.

(2) If the Denon receiver has a "bass peak limiter" type of feature, it should be turned off or properly set (consult the manual).

The issue is a direct result of the recent power outtages. My subwoofer is the only device that wouldn't fit into the surge protector. It sufferend a spike and I'm sol. My insurance deductible isn't worth paying. :-(

Ouch. Sorry to hear that, man. Guess surge protectors are important, huh, guys?

Have you checked to see if the sub's fuse is blown? Most sub fuses I've seen are externally accessible and found near the power plug on the back. Just twist the small gray circle with a coin or screwdriver to remove it. You can get a replacement fuse cheaply from Radio Shack.

If you're really SOL, here's your excuse to get a better sub.

Tim,

Are you sure? I suspect that it is pretty difficult for a power surge to do such a "subtle" damage. I mean, your sub isn't totally broken, but just seemingly lost some amp gains if any, right?

If the sub is at least sounding at low levels, I would still check on every other possibility...

[btw, my last post above was directed to you, not Ken -- my apologies!]