Sub gain issue (1 Viewer)

The gain knob on the back of my Proficient Audio GS10 is being bypassed for some reason. The sub end up sounds extremely "boomy" as well. This is the second time that it's happened, and I have know idea why.

I've turned the unit off and unplugged the LFE cable on both ends. I don't really have any other ideas.

Anybody have any suggestions?

Also,

I understand that the AVR bypasses the subs built in crossover when using an LFE cable. I've always been able to adjust the gain of the sub when using an LFE cable. I just don't understand why all off a sudden the gain knob just becomes useless.

I just recalibrated twice and the AVR has set the subs trim to -12 each time. Usually when you get that result you would adjust the gain knob accordingly, but it still isn't showing any results.

Sounds like the rheostat in the knob needs replaced.

I have a rather small ground loop hum coming from the sub. When I increase the gain, the hum gets louder, so shouldn't the knob be working?

Also, before I run AccuEQ there is a signal that is sent to the sub to make sure that it's actually receiving juice. It's much louder than normal. Could it be the AVR?

It's only happened twice and the first time it was fixed rather quickly. I could use the gain knob no problem and it was giving me no issues for a good amount of time.

Today, It's a nightmare. I was watching TV and the sub started sounding boomy and bloated. I went to check the gain knob and I wasn't getting any results no matter which way I turned it. It just happened randomly.

So "the hum gets louder". Does the actual content being played get louder?If no, time for a new knob. And fix the groundloop. That could be the entire problem.

MasterAudio said:

The gain knob on the back of my Proficient Audio GS10 is being bypassed for some reason.

Click to expand...

There is no way for the gain adjustment to be "bypassed" by the receiver. If you turn the gain dial and there is no change in the volume of the output, then the gain dial is broken. No doubt about it.

MasterAudio said:

Also,

I understand that the AVR bypasses the subs built in crossover when using an LFE cable.

Click to expand...

Not that this has any bearing on the problem at hand, but this is not what happens.

The sub's crossover is not "bypassed", it's simply redundant when connected via coaxial cable to an AVR. AVR's with pre-outs already perform bass management and use their internal crossover(s) to optimize and adjust the line-level signal that is sent to the subwoofer based on the capabilities of the rest of the speakers in the system.

The content being played doesn't get louder when turning the knob from 0-5. It only gets louder from 5-10. I just switched out my 50' LFE cable with my 4 footer to test it and the hum disappeared, so I don't think its a grounding issue after all. I'm eventually going to be running the cable through my wall. Guessing it's time to look for a blue jeans cable instead of a mediabridge.

Jason Charlton said:

There is no way for the gain adjustment to be "bypassed" by the receiver. If you turn the gain dial and there is no change in the volume of the output, then the gain dial is broken. No doubt about it.


Not that this has any bearing on the problem at hand, but this is not what happens.

The sub's crossover is not "bypassed", it's simply redundant when connected via coaxial cable to an AVR. AVR's with pre-outs already perform bass management and use their internal crossover(s) to optimize and adjust the line-level signal that is sent to the subwoofer based on the capabilities of the rest of the speakers in the system.

Click to expand...

On some subwoofers using the *LFE* input jack does bypass some of the controls, often including the crossover control.

Tom V.
Power Sound Audio

MasterAudio said:

The content being played doesn't get louder when turning the knob from 0-5. It only gets louder from 5-10.I just switched out my 50' LFE cable with my 4 footer to test it and the hum disappeared, so I don't think its a grounding issue after all.I'm eventually going to be running the cable through my wall. Guessing it's time to look for a blue jeans cable instead of a mediabridge.

Click to expand...

1)gain rotation sensitivity. It is not unusual for the gain control to have the majority of its "control" limited to one half of the knob rotation.

2)RE the cable----that may indicate the 50ft is not well shielded. Also, check that the 50ft is not running parallel to AC power cords.

3)Both cable brands should work fine.

Tom V.
Power Sound Audio

I've taken apart every component, one by one and the hum persists. Like I said earlier, It MUST be a bad LFE cable. When I change out the 50' connection to the 4' connection it works fine. No hum.

Could this bad cable and hum be the issue as to why my receiver is setting the trim at -12 during each calibration?

Could be. This 50ft...Is it shielded?Does it run in a wall cavity that contains power?

It's running through the small closet with all my components in it right now. Comes from the back of the AVR, down in front on the floor, underneath my closest door to my sub in my room. Thats just until I run it through the wall.

Yes, it is dual shielded.

Yes, it runs in my closest that contains power. How would it not though? When I use my 4' connection to the sub (hum disappears), the cable is still in my closet, and I have to move my sub in there as well for it to reach.

Then...your 50ft cable...has a problem.