Sub Weak Output

[nate0708]

I have just installed a fosgate p3d4 12 in a belva prefab sealed box. Yes i know there are much better subs and a custom made box is recommended which i plan on doing. Haven't had alot of time or money to put into it so it works for now. Got a prime 500 amp powering it running of a Pioneer fx700bt hu. However it sounds really weak on real low bass. For example playing "put on" by young jeezy the 3rd n 4th bass notes are pretty much inaudible. On sum of the higher bass notes it pounds n im pretty happy with it for the most part. Just doesn't get low enough though. I've tested all wiring and grounds and everything is pretty sound. I'm thinking alot of its maybe the box, but when watching the voltage output from speaker leads im getting around 25-30 volts on some of the higher bass and sub is hitting pretty hard but when lower notes hit its dropping all the way down to 10 to 5 volts and the sub is barely moving which makes me wonder if its something to do with the amp or head unit output. The amp has a built in infrasonic filter so can't change anything there and my lpf is set to around 100 hz. I'm not expecting this setup to rattle my rear view mirror off but really feel like it could be better. Any input is appreciated

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[Popwarhomie 5,000+ posts]

when lower notes hit its dropping all the way down to 10 to 5 volts

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[nate0708]

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Sorry but what does that mean lol

 

[Popwarhomie 5,000+ posts]

Sorry but what does that mean lol

What does 10 to 5 volts mean?

 

[nate0708]

The voltage i'm getting from my amp to sub when low bass notes hit. When higher bass notes are playing and sub is hitting good i'm reading around 25 to 30. Sorry im somewhat of a noob when it comes to car audio lol. I'm talking about coming out of amp not voltage to amp. Voltage is good there.

 

[Jeffdachef 5,000+ posts]

The voltage i'm getting from my amp to sub when low bass notes hit. When higher bass notes are playing and sub is hitting good i'm reading around 25 to 30. Sorry im somewhat of a noob when it comes to car audio lol. I'm talking about coming out of amp not voltage to amp. Voltage is good there.

Car voltages should never drop under 12. You have some serious clipping or electrical issues happening. Also make a custom ported box yourself, its not that hard.

 

[r0llinlacs 10+ year member]

What he's saying is the output from the amp to the sub, which is AC voltage so higher than car voltage and completely determines output, drops on low notes.

I'd say he's on to something but I don't know what. Could be voltage drop on the car electrical but I doubt it with a 500.1. Could be the subsonic filter is a switch and set too high from the factory, but something is limiting output on the low notes, could even just be the song.

 

[noble brown]

I'd say you have a problem at the amp or h/u. Also like rollinlacs said it maybe the song. Assuming you've eliminated the song as the problem, monitor voltage without the speaker hooked up. That will tell you if it's the sub, I don't see how I could be but it better to be sure. Next eliminate the amp as the problem. Either swap out the amp or monitor voltage at the RCA's to the amp. The voltage will be a lot smaller but it will just be scaled down. Now if you see the same pattern all the way through the signal chain I'd start looking at the h/u. How does it sound at the rear deck speakers? Check at both ends of the RCA's too. Rollinlacs also said it. may be the factory set subsonic filter. But first you will have to find out which component is the culprit

 

[nate0708]

So tested Rca voltage and had same results. I can play bass I love you and with head unit cranked I'm only getting 5 to 10 volts and sub is barely doing anything. Sub crossover on Hu is set at 80hz. Is my head unit screwed up? I'm playing music using Bluetooth streaming at 320 kbps. Don't know what to try other than new Hu but don't really want to spend time n money on that unless I know for sure this is the problem.

 

[nate0708]

Might be a dumb question but could it have anything to do with using Bluetooth as my source. Like I said sub hits pretty hard on some stuff. I don't really have any cds. Have a Korn cd in right now n getting pretty good output with that but doesn't have the low lows that I'm missing to compare with.

 

[r0llinlacs 10+ year member]

Could definitely be bluetooth source. Try a different source, turn off the subsonic and see what happens.

 

[nate0708]

So the issue definitely seems to be the bluetooth. Anyone else had similiar problems? Not sure if its the bluetooth itself or the source of music which is the rdio app but i have my settings set to 320kbps for wifi and 192kbps on cellular. Haven't bought cd's in forever so don't have much to test with but a Korn and Chimaira cd. Playing the same Korn cd with bluetooth the bass is barely there. Getting much more output with the cd. Tried axillary but think my cable is bad as i only got sound out of one speaker lol. Gonna play around with it some more. Thanks for the input guys.

 

[noble brown]

Yeah check the settings on your BT device. Eq's or something on the device may be doing this. If not look at the settings on your hu for something specific to the BT function. If all else fails find a decent aux cord.

 

[nate0708]

Definitely. Honestly i think what is happening is that when choosing bluetooth on my hu i don't the sub outputs are being used as sub output which would cause enable the hpf on my sub if that makes sense lol. Thus the reason why the lower bass is really getting cut and some of the higher bass still pushes through. I'm going to check but not sure there are any options on hu that will fix this. Might have to roll with the axillary if that will work.