The volume is way to high even on the lowest setting

to check its manual controls mainly problem at micro switches

Need more info. Are you using the volume control on the unit as your main control or the volume on the TV? I have a setup in which my sound is routed through a 5.1 Teac amp. The sound level on the amp os set and not changed. The volume control on the TV dictates the amount of sound. If the amp volume is set too high, then this will be amplified even more through the TV's sound input (the red and wite RCA cables).

If this is the case, turn down one of the folumes (the one that remains unchanged) and see what happens.

If you're drawing audio from the Cable Box, good. If the Cable Box has a variable audio output you might need to defeat it in the menus somewhere. Look for something like "Fixed". That way the volume control on the box will not affect the feed to the GPX.

If you're drawing audio from the TV, why? See above.

I have a coby mp600 anyone plzzzzzzzzzzzzz someone help me my volume is full blast no mater what setting,,,how do i fix this problem plzzzzzzzzzzz!!!

check that your cable box has its volume set all the way up, i suppose you are using one, for the hdmi you can only get video from a comp, you need seperate lines for your speaker, usually there is audio in by the hdmi connectors.

Returned it...I called the manufacturer, they said its defective,return it.

i had the same problem when i tried to adjust speaker output levels, distance and equalizer manually without using audessy setup..so i reset everything to factory setting (0s)..and then ran 
audessy setup..reduce volume on your subwoofer to slightly above minimum(behind the subwoofer) before running the setup..once audessy setup is completed successfully..i started changing setup
manually..changed speaker config for front speaker to small (it is set as large by audessy setup), this should automatically adjust center and other speaker configuration (if not make sure to set them to small as well), then set the cross over frequency to 120..increase the volume on your subwoofer and now you should hear it fire..if this does not help..try playing some rock music with all channel streo mode..if your subwoofer does not fire even for this..then take the system back for exchange..

There are several complaints in FIXYA and they are all about this same fault condition....the volume is too high when turned on...

Because of the high number of complaints about this same fault I would suggest that its a manufacturer fault.

So the manufacturer should be contacted about it to ask for your money back..

Cheers From YUBEUT..

As a replacement for "Dolby Digital DT3 AV cable" can be used a " 3.5mm (mono) to RCA(or coaxal)" Cable.
Just make sure that DVD Player set for "SPDIF/RAW" or "SPDIF/PCM" output

That is unusual, and sounds like a manuf defect. If your unit is still under warranty, I would say send it in. If not, give them a call, and get a quote for repair. Unfortunately, due to the quality and value of these units, it will probably be cheaper to buy a new one.