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Where to cross over

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=30654
Printed Date: May 10, 2025 at 4:18 AM


Topic: Where to cross over

Posted By: vman
Subject: Where to cross over
Date Posted: April 19, 2004 at 8:40 AM

Hey gang,

I'm getting ready to install a new sub amp (Lightning Audio 250.1) and am curious about adding capacitors to high pass my 5 1/4" Infinity reference door speakers. The sub is an Infinity Reference 1233 12" in a 1.25  ft3 enclosure. Would this be worth while, or should I use the internal x-over in the sub amp and not worry about the bottom end of the 5 1/4's?

Also, I have a Blaupunkt San Jose head unit that has 2 sub-out jacks. The manual and the 800 tech line have no idea as to whether or not this is a pre-crossed output. The tech guy thought the output would be 100 HZ and below, but was not sure. Any idea as to what the output would be? What's normal for a sub-out frequency in other decks?

The Volvo is rockin', thanks to all of your help.

Thanks,

V




Replies:

Posted By: DYohn
Date Posted: April 19, 2004 at 10:44 AM

I believe the MP41 (San Jose) had user adjustable sub-out crossovers, but I'll check to be sure.  In any case, 5.25" speakers really have very little usable output below about 100Hz, so if you want to get some "bass blockers" as they are called, start looking around this frequency value (or if you are building a high-pass crossover yourself, 6db/octave @ 4ohms @ 100Hz = 398 uf)

Be careful that you do not cross your drivers over too high and yur sub over too low, or you end up with a "hole" in the sound right at a critical frequency.  5.25" mains with a sub is one of the hardest setups to get right wthout some mid-bass reinforcement.  If you cross those mains at 100Hz, you'll want your sub crossed at around 120Hz.



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Posted By: DYohn
Date Posted: April 19, 2004 at 1:07 PM
OK, the San Jose MP41 has an internal sub out crossover of 100hz and is not adjustable.

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Posted By: vman
Date Posted: April 20, 2004 at 9:38 AM

Thanks DYohn.

If it's not something you would have to kill me for, could you reveal your source for the info on the San Jose? I can't find squat.

Thanks,

V





Posted By: DYohn
Date Posted: April 20, 2004 at 9:45 AM
vman]< wrote:

>Thanks DYohn.

If it's not something you would have to kill me for, could you reveal your source for the info on the San Jose? I can't find squat.

Thanks,

V


:)  I called Blaupunkt.



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Posted By: vman
Date Posted: April 20, 2004 at 9:48 AM
You must know the secret handshake. The guy I got was dumb as a bag 'o hammers!




Posted By: DYohn
Date Posted: April 20, 2004 at 9:54 AM
I used to be sponsored by them and I still know a few people.

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Posted By: vman
Date Posted: April 20, 2004 at 10:09 AM

Well, thanks for the help.

The system does sound good as is, but I think a little tweaking will clear out a lot of mud.

Thanks again,

V






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