Sub problem?

[Buckle-meister]

Dear all,

Tonight I was watching a DVD and was almost at the end of it when I heard a 'bump' noise from my sub which I was fairly sure was not part of the soundtrack. A few minutes later, it came again. At this point, having already turned down the volume, I switched everything off.

Starting the process of troubleshooting, I replaced the DVD with a CD becuase the DVD was just bought and I wanted to see if the problem persisted with a CD I knew to be fine. It did.

Next, I tried using the coaxial digital as opposed to the i-link cable. Still the same. Then I used my old Musical Fidelity CD player instead of my Yamaha S2500 (which I currently use for both CD's and DVD's). Still the same.

By now, I know for a fact that the problem does not lie with my S2500, and must lie either with the Yamaha Z9 amp, or my sub itself. Since my CD does not have a LFE channel, I am reproducing sound from the sub by putting the Z9 into '9 channel stereo' mode. The thing is; when the 'bump' occurs, it does not come from any other speaker (i.e. FL, FR, C, SL or SR).

Do you agree that this means the fault must lie with the sub?

Regards

EDIT: I thought of a possible problem with my hypothesis; all my speakers were set to small. I changed my FL and FR to Large, but the problem, now much worse sounding still comes only from the sub.

I am now pretty convinced that it's the sub. Do you agree?

 

[AVRat]

Have you tried running the system with no sub yet? I.e. changing the setup to no sub or disconnecting it.

 

[Buckle-meister]

Have you tried running the system with no sub yet? I.e. changing the setup to no sub or disconnecting it.

Last night was the first time I had the problem appear. I listen to two channel only through my front towers, so the sub's never switched on then anyway.

With the sub off, the problem does not occur. With the sub and '9 channel stereo' mode on, and the towers alone switched to Large, the noise comes only from the sub, not the towers. The question is now a bit academic because I took the sub to the shop today for them to take a look at, but this morning, even with the sub switched off but '9 channel stereo' on, my towers exhibited no problem whatsoever. This is what makes me think that it is the sub at fault.

Typically, I tend to think that speakers very rarely are at fault or break down. If a person hears a problem, it's usually the speakers letting them hear a problem with another component such as the amp through them. But since the sub has its own built-in amp, I think that maybe the fault lies there. If it does, I don't think the problem is with the actual driver, but with the amp section itself.

It's as if it's buliding up some sort of charge, and then 'bump' letting it go suddenly. Don't know if any of this makes sense, but I think my troubleshooting reasoning is logical.

Time will tell.

Thanks for the response. Much appreciated.

Regards

 

[mtrycrafts]

Last night was the first time I had the problem appear. I listen to two channel only through my front towers, so the sub's never switched on then anyway.

With the sub off, the problem does not occur. With the sub and '9 channel stereo' mode on, and the towers alone switched to Large, the noise comes only from the sub, not the towers. The question is now a bit academic because I took the sub to the shop today for them to take a look at, but this morning, even with the sub switched off but '9 channel stereo' on, my towers exhibited no problem whatsoever. This is what makes me think that it is the sub at fault.

Typically, I tend to think that speakers very rarely are at fault or break down. If a person hears a problem, it's usually the speakers letting them hear a problem with another component such as the amp through them. But since the sub has its own built-in amp, I think that maybe the fault lies there. If it does, I don't think the problem is with the actual driver, but with the amp section itself.

It's as if it's buliding up some sort of charge, and then 'bump' letting it go suddenly. Don't know if any of this makes sense, but I think my troubleshooting reasoning is logical.

Time will tell.

Thanks for the response. Much appreciated.

Regards

Is this an auto sub, on off to input signals? That may cause the sound when the amp is powering up or down?

 

[Sheep]

well, first why don't you tell us what sub it is. Thats the first thing to get out of the way.....

If you have another sub, test it, or borrow one, or steal, just get another sub. That will solve the problem of reciever or sub. Then if the other sub doesn't screw up, fix. RMA, or hit the subwoofer and get a new one.



sheep

 

[Buckle-meister]

Is this an auto sub, on off to input signals? That may cause the sound when the amp is powering up or down?

Yes, the sub automatically switches on when it detects a signal (the led changes from red to green). However, the noise does not occur at the point at which the sub 'kicks-in', but typically after 10 minutes or so of listening to whatever material is being played.

...why don't you tell us what sub it is. Thats the first thing to get out of the way...

Not quite sure why this would be important, but it's a Mission e8as1.

If you have another sub, test it, or borrow one, or steal, just get another sub. That will solve the problem of reciever or sub.

True, but I do not have an alternative sub to try.

Thanks folks.

Regards

 

[mtrycrafts]

Yes, the sub automatically switches on when it detects a signal (the led changes from red to green). However, the noise does not occur at the point at which the sub 'kicks-in', but typically after 10 minutes or so of listening to whatever material is being played.
Regards

OK, then, does it turn off then, when this noise happens?

 

[Buckle-meister]

OK, then, does it turn off then, when this noise happens?

No. When the noise occurs, it is me who hastily switches off the sub!

Regards

 

[j_garcia]

Sounds like a problem with the sub's amp or related circuitry to me, since it doesn't happen when you listen with it off. Have you adjusted the gain on the sub down and does it still do it? If it does it at any volume, it is most likely the sub.

 

[Buckle-meister]

Sounds like a problem with the sub's amp or related circuitry to me, since it doesn't happen when you listen with it off. Have you adjusted the gain on the sub down and does it still do it? If it does it at any volume, it is most likely the sub.

Sorry for the silence J Garcia, I thought this thread was dead and hadn't been keeping an eye on it. Or rather, I was spending too much time in The Steam Vent instead of on more mundane matters!

I never tried what you suggested. The sub's gain was normally set at slightly less than half its dialable amount. The crossover was set at max due to the amp's crossover being set to 80Hz. It's now too late to say, as the sub has gone to the shop for them to take a look at. If they are able to duplicate the problem, at that point they will forward it to Mission to fix/replace.

It was Sunday when I took the sub to the shop. I've not heard anything back from them, so I assume that they also were able to duplicate the problem. This is very upsetting to me. It's only twice I know, but I've never had so much go wrong so soon with gear before. It's still within the manufacturers one year warranty, and as part of the package, I got a three year warranty so there's no problem there. But when something 'goes', gets fixed and comes back, it's that awful feeling of a lack of confidence that I can't stand. I almost feel I'm listening for something to go wrong. Still, given a little time without a hitch, it soon disappears.

Oh well.

Regards