View Full Version : My subs lose all clarity at high volume (+pics of my box)

05-17-2004, 11:17 PM
Hey everyone,

I just wanted to say thanks, I finally got my box finished last week, and my subs in it and everything. The advice I got on this board was really helpful, this is my first setup.

Here are two pictures of my setup. http://gallery.caraudio.com/pp/showgallery.php?cat=500&ppuser=13311

There are two Alpine Type-Rs 12"ers running on a Hifonics BX 1000D amp.

I have two problems, or questions though.

When I really crank these things up the sound clarity goes way down. When I have the volume at a moderate level the SQ is very good. But when I crank the volume the bass loses it's punctuation and clarity.

The second question/problem is that a lot of the time, this doesn't happen with all music I play, but with a lot, the bass drones and rumbles and sounds a little less punctuated than with some other set-ups I've listened too.

The first two ideas I had here were to add Polyfill too the box, and then that maybe I had my amp tuned to the wrong frequency. I actually have no idea what it should be set at.

Thanks guys. Any advice would be cool.


05-17-2004, 11:21 PM
You might want to try to turn your gains down.

05-18-2004, 07:51 PM
I will try that. Thanks.

Would Polyfill make things any tighter?
Could things be getting messy at high volumes because my RCA cables are getting interference? or they aren't good enough cables?

slick rick
05-18-2004, 07:58 PM
check your gains and bass boost and your LPF.

05-18-2004, 08:43 PM
NO poly fill will not make it tighter. Poly fill makes the speaker think it is in a bigger box than it really is. It almost sounds like you have too much airspace for those speakers. Does that box have 2 different channels. (ONE FOR EACH SUB). Each sub should have its own chamber. I would set you gain to about 3/4 at the highest. Your LPF (low pass filter) to around the 100 mark, and set your Bass Boost to about 1/4.

You may also have a wire problem. If you did not make a good ground your amp is not doing all it can do. IT will strugle to push out the power you are asking it too. You will make the amp work twice as hard and it will not sound as good.

Your HU may be reaching its distortion level way to early. I do not know what type of HU you have , but my guess is you are not running high voltage preamps on the HU. If you get some of the better HU they are putting out twice the VOLTS on there RCAs than others and with that you will get the amp to respond sooner and cleaner. A lot of people think THIS AMP *****, when it is not the amp. They buy a **** HU and put a ****** signal into an amp, well what do you think the amp is going to put out. **** your right. if you are putting distortion into the amp you will get it out. (I AM NOT SAYING THIS ABOUT YOURS) But that may be another option.

Answer these questions

Are there 2 chambers in that box?
How much Airspace per chamber?
What do those speakers call for? (airspace sealed)
Did you set your amp to the settings about and did it help?

05-18-2004, 11:11 PM
My box has one chamber per sub, each chamber is 1.1792 cu/ft. And then the sub displacement is .163 with a rear mount, I think thats what I have. so that brings the volume per sub to about 1 cu/ft.

alpine recomends .7-1 cu/ft per sub, so I think I'm ok for that.

And I turned down my gain, it's set just under half, and my bass bost is pretty low.

My low pass ranges between 15hz and 25hz. I have it set about half way

And the subsonic filter is at 0.

05-18-2004, 11:24 PM
My low pass ranges between 15hz and 25hz. I have it set about half way

And the subsonic filter is at 0.

i think that's one of your problems. if i am correct n if this is what you said, your LPF is set at somewhere bet 15hz to 25hz, it's very low i ll say. set your LPF to somewhere bet 80hz and 120hz.
also, the distortion at high volumes, have ur subs been broken in yet? sometimes w brand new subs, it takes a little while for them to sound the way they supposed to. to break them in, just play music at moderate levels for a few days to a week i ll say. then after that they should be beter.
and the most important, set your gains correctly, ur subs might be distorting n that's why they sound like crap at high volumes.

05-19-2004, 01:13 AM
Thanks guys,
Ok I got the LPF set at around 100.
I was reading it wrong...

Also I've had the subs in for about a week and half, so I assume they are broken in.

And as for the gain... I have it set about half way. I really don't know how to set it right to be honest.

Thanks again guys for your help, It's made an improvement.

05-19-2004, 03:13 AM
LPF between 80 and 120 ? That's too high in my opinion, it'll draw the soundstage to the rear ... Set between 50-75 Hz ...

personal preference i think tho. i usu set it at 80hz, and been happy with all the installs so far.

so then i guess u run speakers from 50hz to above? how does the bass out of them sound?

05-19-2004, 05:00 AM
mine is set around 60 as set by dave (team ******) and its bangin. turn down the bass on your head unit and things like that.

just toy with it for a day or so until u get it to sound good at those high volumes