Aftermarket Head Unit is weird? Can anyone help?

[madeitog]

I have a JVC r320. terminators, and powerA amp. the amp is ideal for the subs and etc. The weird part is that, when i set my head unit to the subs in the back. They barley kick? Now the head unit has 2 options, rear or sub/w. Now obviously i want to just use the subs because my car has old speakers. Now when i set it on rear they kick hard then the speakers start to do the bass and distort in some way. But mostly try to hit the bass and they can't of course? Everything as far as the rca cables from the back of the unit to the amp is right? But is their anyway to fix it? like any? Someone help

Click to read more...

 

[i2ain2thunder 10+ year member]

most head units that have subwoofer preouts have a setting for the level on the subwoofer channel. You may need to adjust this, maybe it is at a - level. Of you may need to adjust the gain on the amplifier. What are the current settings on your HU and amp? please on headunit please provide bass= treb= EQ= subw= loud on or off, anything you can think off that affects sound. Next on amp provide LPF frequency setting, HPF frequency setting, crossover setting (is it set to HPF, LPF, or full range?) Gain level= bass boost=

 

[madeitog]

yes, it has a setting for it. but when u put it on the setting. the subs don't hit as hard. u have 2 setting rear, and then sub/w. i turned the bass all of the way up when the setting is on sub/w. and barley anything with rear it hits the normal bass. but then the speakers mess up. the gain on my amp is close to the top, but its mid way from full and middle. treb is on 2. loud was switch on and off and nothing. lpf on the amp is around 120? and when i set my head unit to rear and then theirs a setting on the head unit for HPF i turn it on and the speakers work very well then the subs go back to not hitting barley at all. bass boost it almost all the way up on the amp?

 

[i2ain2thunder 10+ year member]

Well my first advice here is that you are going about things wrong.

Unfortunately this is the same thing everyone who is new to car audio does when they want more bass. The truth is anytime you boost a frequency (turning treb up, turning bass up, turning bassboost up. upping your EQ) Are all things that are going to add distortion to your signal. Distortion will cause clipping, distortion and clipping together will destroy your speakers/subwoofer. The unfortunate truth may be that your system doesn't get as loud as you would like, and the solution to this should be to get different equipment.

So I want you to put the RCAs on the Sub/W. Turn bassboost completely off. Turn LPF down to around 80hz. Use a DMM to set your gain by the equation √(total wattsxtotal ohms) IE you have 2 dual 4 voice coil subs that are rated 150rms, you have them wired to 1ohm at the amplifier. Disconnect your sub(s), turn gain to 0 turn volume on HU to 75% of max. play a 50hz tone either via CD or aux. Hook up Digital Multimeter (20$ at radioshack) to output channel on amplifier set DMM to AC voltage. Now turn gain up slowly until you reach the number you need from the equation. So 300watts x 1ohm = 300, √300=17.32 so turn up gain until DMM reads 17.32 for this example. When you have that all set, that is now your max volume on your HU. Turn any bass and bass boost to 0. This is as loud as you can get safely for your subwoofer(s). As for your speakers they may need to have a HPF on them so they don't distort at this volume, or you may need to set HU volume to the max that the speakers will take without distortion, then run the testtone and set gain.