I just an Mtx 942 amp to push my Kicker L7 ina 4ohm load. I Had a Fosgate Power before that, it gave its life in the name of bass. Anyhow, I seem to have to run this amp with the gain at full to get any bass out of it. The mtx people said to add signal voltage, My Alpine is 4 volt pre out and I have a PG line driver with 10 Volt max output. If I have the line driver set at 4 volts, does the amp see a 8 volts. Basically what im asking is does the line driver just add to the voltage of the hu or does it cancel it out and just send its own voltage?? I thought it would cancel it out but someone told me otherwise. I thought I would ask all the experts out there.
A line driver is a signal amplifier. Personally I don't think you need one. With a 4 volt pre out you should have plenty of signal. If you have the gain turned all the way up, something else is wrong. Either you need more power, more speakers or a better designed enclosure. Many people make the same mistake and think that the gain control is a volume control, it is not. Its purpose is to match the amplifier to the head unit. The line driver does not add to the signal. Let me explain it this way. If you input a 4-volt signal and you turn the line driver down to 2-volts (if its possible with that line driver) all you will have is 2-volts out. My suggestion would be to try the line driver (the amp may not like that much signal in) but if you can't turn the gain down to around half, I would seriously consider another game plan.
Mtx tech said to go with more signal voltage. Im pushing 1 L7 in a Sealed Kicker box at 4 Ohm with 2 pounds of polyfill in the box (its sealed). The 942 will do about 980 clean watts at 4 ohm bridged. I am running 1 awg wire to a 2 farad cap, a yellow top optima and a 130 amp alternator. Dont get me wrong, it hits very hard but my concern is that I have to run the gains at full for it to hit. My old fosgate was running at about 3/4 gain and it hit pretty good. Any ideas where im going wrong??
Does the L7 hit as hard or harder than your old Fosgate...May be your trying to get out more than possible...A bigger or vented box may give you the extra thump your looking for.
Try the line driver and see what happens. If you were one of my customers, I would suggest a ported enclosure. If the primary concern was hit and intensity then I would buid the enclosure to work with the resonent frequency of the vehicle. Resonent frequency of the vehicle is easy to determine, and all we need is a tape measure and a calculator. The enclosure is a little trickier. You will need a program called WINISD, its a free download and it will help determine box size and port tuning. So if you what to build something post back.
WINISD is a sweet free program...you'll just have to read the help files to figure out how to properly use it.
It hits and sounds fine, 151 db in the drivers seat with a Radio shack db meter. My only concern is that to get that I have to run the gains at full which I think is a little strange. There is no clipping but then again this amp has a compression circuit and it does not seem to run all that hot. Just wondering if its ok to run the gains at full???
Um...as long as the amp is not clipping than it is ok... Could get another sub and/or vented box if you want some more thump in your trunk.
