bottom out

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=16021
Printed Date: July 17, 2025 at 4:07 AM

Topic: bottom out

Posted By: red_1
Subject: bottom out
Date Posted: July 08, 2003 at 1:29 AM

I have two 900 watt amps and two 12inch type R subs. They want to bottom out at lower bass tones. What would be causing this to happen?

Replies:

Posted By: wvsquirrel
Date Posted: July 08, 2003 at 2:18 AM

1) What exactly do you mean by "bottom out"?
2) Which model Type R? There are at least 3 different ones that I know of.
3) What is the make/model of the 2 "900 watt amps"?
4) What type of enclosure are you using? Sealed, vented, bandpass...

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Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
Donate to the12volt.com

Posted By: red_1
Date Posted: July 08, 2003 at 2:56 AM

Two MRD-M500 V12 Alpine amps

Two SWR-1241D Alpine subs

CDA-7897 Alpine head unit

Vented enclosure

Posted By: red_1
Date Posted: July 08, 2003 at 3:21 AM

The cone will overshoot and start hitting the frame and bottom out in the magnet's air gap

Posted By: wvsquirrel
Date Posted: July 08, 2003 at 4:15 AM

Well, the SWR-1241D's are 4ohm DVC's rated at 300RMS 1000Peak. The MRD-M500's are Class D amps rated at 500 x 1 @ 2ohms based on 14.4 volts, should be around 450 x 1 @ 2ohms based on 12 volts. You should have each sub wired in parallel to it's own amp like this for a 2ohm load per amp...
posted_image

You're not overpowering the subs with only 450 watts per sub, so the next logical step is to look closer at the enclosure.
What size is you're vented enclosure, and is it a custom box or store-bought? What size/how many ports are there?

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Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
Donate to the12volt.com

Posted By: emarald
Date Posted: July 08, 2003 at 9:46 AM

yeh, vented boxes are designed with a particular tuning freq. go lower and the box unloads and sub x-max goes exponential, very damaging to spiders/surrounds/cones/your back pocket, also bass becomes non existent at freq below tuning freq.

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I need more power.....

Posted By: deftonekorn1002
Date Posted: July 08, 2003 at 3:24 PM

emarald wrote:

also bass becomes non existent at freq below tuning freq.

not true the roll off of frequencys below the port tuning is much quick then that of a sealed box the bass is still there but not is not as loud

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whoaaa

Posted By: red_1
Date Posted: July 08, 2003 at 3:36 PM

The box recamended is a 1.3 cubic foot enclosure with a 4in by 14 inch port. The box that I have is around 1.55 cubic foot enclosure with 4 inch by 14 inch ports. Could it also be possible that not having any capacitors or batteries could be causing the subs to bottom out?