Volume too low

Make sure your frequency is no higher than 80 on the low and 120 on the high. Check speaker polarity with a AA battery(Speaker pops out when polarity is correct) Make sure the speaker crossovers are working properly. Check your ohm load when you connect the speakers together with a multimeter at the amp. Ohms that are too low = heat. See what your amp is rated for. After all that, turn the gain down all the way, turn up the volume to 25-28 and readjust the gains

It's possible that a small pre-amp has failed inside the unit. Hence the low volume.

Make sure all your connections are tight , really tight . Check ground , make sure it's to clean shiney metal. Three subs are going to have a low ohm load if paralleled . These amps are not 1 ohm stable ,if below 1.5 ohm's you will have problems. They need to be series paralleled to raise the ohm load. These amps put out the same power from 4 to 1.5 ohms.

speaks are hooked up wrong or speakers are blowin.

amp goes on protection few reasons
goes on protection, improper speaker connection,improper speaker class, speaker out-put damage (needs to get repair)

Your speaker volume must have reset. You have to touch the dots on the right speaker to turn up the volume to desired volume. I just remembered that on my system. Hope this helps.

ive had problems kinda like this ... normaly its a crossed or reversed speaker wire check the positive and negitive wire into the speakers "they move sometimes when there is more air moving around the speaker"

second make sure you have the impedence correct "possitive to positive negitive to negitive'

hope this helps

check the voltage supply rails to the audio output, usually between 14 and 30 volts. if low replace respective rail capacitor for being open circuit. also check the fusible resistor for high value.
ive also had later model lg sets with a crook audio detector ic crook, the one marked micronas.

You need to look got the amp for the sub if there is not one there is notting you can do. If there is one then just turn up the gain on the amp.
If not there are some times the gain is on the radio in a setting and the only way to find that is to look in the user manuil.

I used to have a set of speakers with 'poly switch' over-current protectors (kind of a 'soft' fuse the size of a small ceramic capacitor) installed in-line with the speaker terminals. (Each speaker in an enclosure needed its own device.) The theory was they appeared as a dead short until their rating was exceeded, going open-circuit to protect the (assumed, more expensive) speaker element. When things 'cooled down' it returned to the former short status and the speakers came alive again. Testing the device with a decent drive signal (it worked), I noticed the sound 'strangled' and only a low-volume, higher-frequency component of the source signal was heard through the speaker. (So I guess it wasn't *totally* open circuit...) After a few seconds of signal removal (and reduction of source volume) the sound came back to normal. Here's my thought: Perhaps your speakers have these devices installed and the devices are operating accordingly. Of course, if the source signal is of a known low-volume, then it sounds like an amplifier component is failing on load. Especially if the speakers behave normally using another amplier. Cheers...