Subwoofer faint - is it bad?

[hk94]

I am running a Marantz sr6009 receiver and trying to connect a Polk DSW Pro 550 subwoofer. I think the sub is bad, but I want to see if there is anything else I can check before I return it. It was a gift from someone a few states away, so dealing with the return will be time consuming. I'm hoping there is something simple I'm missing.

The Marantz has two subwoofer outs in the pre out section. I have tried both. I connect to the LFE port in the line in on the sub, both with just the subwoofer cable and also with a Y splitter. I've set the receiver to front speakers small, sub on, crossover at 80hz. And the output I get from the sub is barely audible. I have to turn up the sub volume all the way, and set the channel to +10db on the receiver to hear anything. It sounds like the sub is not amplifying the line in, and the output is just at the line level.

Any suggestions on what else to try? Running speaker terminal connections isn't an option for me based on other components in the system, so I need to make LFE work.

 

[yepimonfire]

Does your receiver have preouts for the main channels? There could be something wrong with the sub output on the receiver. I would set the fronts to large and attach the subwoofer to the front l/r preouts and see what that gets you. If you get better volume, it's probably the receiver. It's not likely the subwoofer driver is directly receiving the line level signal, there is too much circuitry between the inputs, crossover, and amplifier to simply pass a line level signal onto the driver.

Other things to try would be switching the sub from lfe mode to whatever other mode allows you to use the crossover (different names on different subs).

If it turns out the sub is the culprit and it must be returned, don't replace it with another Polk sub. Polk audio makes some damn fine speakers that will outperform more expensive lines but their subwoofers are garbage. You could do better for even less price.

Also post a picture of the back of the sub as is configured, perhaps some switch or setting is not set correctly.

 

[hk94]

Thanks a lot for the suggestions - I really appreciate all the help I can get. This seems like common sense after you suggested it, but I guess we all have to start somewhere, right?

Here is the back of the amp

So my pre out for front goes to a 2 channel preamp, and I know that's working. Not wanting disconnect everything, I tried preout for the center. I got the same results. I then disconnected the front to the preamp, and setup the sub there. Only slightly better, but I had to crank up volume on the receiver to 75 to get noticeable bass (I usually run the system at 40-45 volume, so this is very loud). I've turned LFE on and off (those are the choices with the Polk), still no change. I replaced the preamp, and confirmed that my front channel works great.

Sounds like the Polk is the culprit, unless there is something very stupid I'm missing on the back.

Thanks again for the help.

 

[hk94]

Apparently my photo didn't link, trying again.

 

[yepimonfire]

Is it set to on, auto, or standby? Why are both cables connected? Try just connecting only one of the outputs to one of the inputs (whichever one says mono). Disconnect the second output from both the sub and receiver. Last, try another cable, even if all you have is a spare video cable, it's all the same thing.

Have you tried the high level inputs? I know you said it would be complicated to do so but considering you've got the front lr connected to a separate amp you could just hook the receivers high level outputs directly into the sub. Btw it's not necessary to wire the sub into the amp and then the speakers into the sub. A couple of twisted together speaker wires attached in parallel will work just fine.

 

[hk94]

I've set it on auto, on, and standby. Currently on standby.

I was playing with several cable configurations. I took that picture after I had plugged it through the front pre-out, and using a different cable than I had been using to eliminate cable concerns. I've been testing mostly with a subwoofer cable just going into the left in.

The reason I haven't used the high level outputs is I don't have a sub channel on the receiver to wire it in on. The only sub channel is on the pre out. If I were to do this, which channel would make the most sense?

 

[yepimonfire]

Front left and right, set the fronts to large and have the sub set to none.

 

[vsound5150]

You only need one cable to the left side subwoofer post and then try setting the Marantz Subwoofer mode setting to LFE+Main. It's probably set to the default setting LFE thus the faint audio. Check if remote has a Night button, turn it off.

Run through Audyssey calibration again.

 

[yepimonfire]

You only need one cable to the left side subwoofer post and then try setting the Marantz Subwoofer mode setting to LFE+Main. It's probably set to the default setting LFE thus the faint audio. Check if remote has a Night button, turn it off.

Run through Audyssey calibration again.

That would send the bass to both the fronts and sub, which is not a good idea. If you're using audyssey shut off the eq, might be a bad calibration