Lost sound on JVC TV

no u will need the factory values of that model of tv to be able to balance them check with jvc for the values u will have to access the ez menu where u will balance the offset as given in the factory values do not do anything u did not go for cos u will distort other parameters u will need a tech

If speakers are not turned off in audio or main menu and not muted and not a box with the sound down---do you hear anything if put ear right to speaker?

Convergence needs repair. The AV48WP30 convergence repair kit from www.tvrepairworld.com has the parts and the CD with step by step repair instructions.

The "hd cord" you're using is probably a DVI cable; they don't pass audio. For this to happen, you need an HDMI cable.

if all you have is bass sound, get into the menu and turn the center channel in option off, this will restore your sound. that is for if you want to use your tv speakers for center in a surround sound system.

It sounds like the begining of as convergence problem or cold solder on convergence board - have a tech have alook

Audio board died take it to a service center. if parts unavailable time to invest in a HDTV set since the HDTV transisition is June 12th and there may be a chance it will not have parts soon.

There might be some features that the universal remotes aren't able to do. To perform the convergence alignment you should have the original remote.
Do you have the user manual or service manual?
The service manual will explain this process better.

Use remote, sounds like Tv is in child lock

Sounds like you lost the High Voltage. The beating sound is the power supply trying to start up. After a predetermined time it will quit to protect the set. This is a very common problem and typically not that much to repair. If you are not an electronics repair technician you should find a reputable repair shop and enlist their services. I would not think the cost should exceed $150.00 to repair. Good luck.