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improve an existing system

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=77997
Printed Date: October 31, 2024 at 5:58 PM


Topic: improve an existing system

Posted By: radiofreak88
Subject: improve an existing system
Date Posted: May 18, 2006 at 8:07 PM

i have a 8" sub and a 200 W amp the sub has 2 4 ohm vc's and the amp is 2 ch and 4ohm mono bridgeable. i plan on building a better box for the sub the biggest size suggested by the manufacture is what im going for but i was wondering if theres any more that i can do to get a little more out of this sub b/c i can afford to buy nothing else right now. for anyone seriously interested in helping me ill find the site for the subs and amp and post it ASAP. i know there not super but hey they work better than nothing for now !



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rattles suck lets hear your system



Replies:

Posted By: stevdart
Date Posted: May 18, 2006 at 9:03 PM

You're on the right track with box size.  The larger size increases the efficiency.  Before you build the box, do this first:  look at the parameters of that sub.  Find Fs and Qes.  Do this math:  Fs / Qes = __.  If the number is over 60 look into building a vented enclosure.  Post up with the results.



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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.




Posted By: danieljaluise
Date Posted: May 18, 2006 at 9:10 PM
You have a few wiring options, check out this woofer wiring guide:
dual 4 ohm voice coil wiring options for a single woofer

You can't use option #1 because your amp is only 4ohm stable in bridged mode. Option #2 will work, but I'm not sure how much power you will get out of a 200watt amp running at 8ohms. It might not be enough to run the sub efficently.

The third option is to treat each voice coil like a seperate speaker and wire each one to a channel on the amp. The only danger in doing this is if the right channel signal differs from the left signal, the sub will be damaged. If you combine the right and left rca signals to a single mono singnal before it reaches the amp, you shouldn't have a problem.

What kind of vehicle is this going into?   I'd try to make a ported box to get more sound out of the speaker.




Posted By: boug0752
Date Posted: May 18, 2006 at 9:55 PM

Hello Stevdart. I have a quick question. I'm actually in college right now for Mechanical Engineering and taking a Phyics 2 (Electricity and Magnestism) course which is really making me realize and have interest behind the mathmatics of the subs. You mentioned previously in this post that Fs/Qes>60 to consider a ported box. I just did this measurement with the numbers I could find for my Kicker L5 and the number was only 53. Yet it obviously sounds much better in a ported and tuned enclosure. Can you explain the reasoning behind the number of 60 and what this represents?

Thank you stevdart, you've always been helpful in the past,

Jon



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If your counting pennies and dimes then maybe you shouldn't be spending every penny and dime you have!!




Posted By: stevdart
Date Posted: May 18, 2006 at 10:16 PM

Yeah, that's true.  And you'll see the caveat about that I wrote in the WinISD guide.  Maybe it's that square shape?

But as far as the number goes, it is a representation of the EBP.



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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.




Posted By: haemphyst
Date Posted: May 19, 2006 at 12:32 AM
danieljaluise wrote:

The only danger in doing this is if the right channel signal differs from the left signal, the sub will be damaged.

That is ABSOLUTELY incorrect. A common misconception, but there is NO danger whatsoever in "mismatched" channel outputs! You could even wire them completely out of phase and no damage will happen, except you'll get no output... Clicky, read the entire thread, (be sure to follow any links posted as well... they have additional info regarding this) and you'll understand this better...

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."




Posted By: boug0752
Date Posted: May 19, 2006 at 11:24 AM

Thank you as always. Its amazing the amount of knowledge that you have in the electrical field. Thanks a lot again stevdart.

Have a great one,

Jon



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If your counting pennies and dimes then maybe you shouldn't be spending every penny and dime you have!!





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