Why does my subwoofer only work sometimes?
 

I have a Yamaha YST-SW305 subwoofer connected to a Sony STR-DE485 receiver. Sometimes my subwoofer will stop working for no apparent reason. Sometimes it works for a couple or hours, and sometimes it keeps working for a week. I just realized that if i turn the volume up really loud then the sub kicks in. I can turn the volume back down and the sub will keep going, but only temporarily. I have standby mode set to off on the sub. Is there anything I can do to fix this?

Well if the sub is not faulty it could be several things.

What is the receiver set to? Auto format decode?
What is the subs crossover set to? How is the sub connected?
If that is a 5.1 receiver what did the LFE test do?

On what material do it work or not work on?

I should have mentioned that I use this set up mainly for music, so its just 2 channel stereo sound.

bv3,

Hopefully you have a crossover setting, and I would set it to around 100hz-120hz to start. Your sub may not be able to handle the lower frequencies, and only the higher bass frequencies. The fact that you have to turn your receiver up to high volume to get some bass, tells me your receiver may be the problem--it doesn't have enough power to kick out a low frequency when an audio passage requires it.

Also, is this an Active or Passive subwoofer. If it's active, you should be using a line output from your receiver and NOT a speaker cable output.

Thanks for your help. Here is some more information: The subwoofer has a variable crossover from 40-140hz. No matter what I set it I don't get any sound. It is an active subwoofer and I have it connected to the line output. I have tried it both ways with it connected to the speaker outputs and to the line output and it doesnt seem to make a difference. I have the same problem either way.

Is there a size setting on you reciever to tell it what size your front R/L speakers are? Something like Small/Large? I ask because my receiver does, and if it's set to large then the sub only works sometimes. When it's set to small, it works all the time.

Don't know if it's the same, but it might give you another quick avenue to explore.

Ok, I changed the speaker size to small but I am still having the same problem. Obviously something is not working right, but how can I tell wether it is the receiver or the sub?

Thanks to everyone who has offered help.

My receiver works the same way. If Front R/L is set on "Large" my sub only kicks in while playing DD5.1 or DTS movies.

Did you set to "YES" under sys/spk set-up for subwoofer in your
receiver it could the cause

Yep, and on mine when it did it was way underpowered.

hey bv3, i have the exact same subwoofer you have. I had the same problem too. ( i got a great deal on all the stuff i have.. i bought it off a friend). I have a yamaha 5490 receiver. This might help you, it helped me tremendously, and now my sub works pretty well.

what i did was i layed my sub on its side, and it has started to work MUCH better, i dont know why, but it works for me.