tips for speaker box
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=67836
Printed Date: April 29, 2024 at 6:44 AM
Topic: tips for speaker box
Posted By: reinkster
Subject: tips for speaker box
Date Posted: December 06, 2005 at 8:41 PM
I was planning on making my own sub box for my 1991 chevy astro that i am customizing. I was planning on using 3 10inch subs with a one channel amp for each. I already have a layout planned and just wanted some tips from some of the more expirenced builders.
Replies:
Posted By: sedate
Date Posted: December 06, 2005 at 9:00 PM
Uhh. If you wanna lighten ur load a bit use 1/2" MDF and lotsa fiberglass resin on the inside of the box.
Why seperate amps? A single large monoblock would be far less taxing on your cars electrical system, not to mention better suited for running a common enclosure with summed subs... I can think of a few *vicious* 1000+ watt amps for that would run the bejeezus out of a 2.67 ohm load...
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"I'm finished!" - Daniel Plainview
Posted By: reinkster
Date Posted: December 06, 2005 at 10:28 PM
hey thanks! i really wasnt sure what to do with the amplifiers. do you have any suggestions on amps that would be good for this. I'v had a hard time finding any.
Posted By: reinkster
Date Posted: December 08, 2005 at 5:34 PM
Im planning to make a sub box using 3 10inch subs for my 1991 asto.i have the subs picked out i just need some advice on an amplifier. Also any advice on making the sub box would be nice.
Posted By: OCURIEL
Date Posted: December 08, 2005 at 5:39 PM
what's your budget?
what subs do you have?
Posted By: reinkster
Date Posted: December 08, 2005 at 5:42 PM
I was going to get Blaupunkts pc series 10inchers. im not looking for anything too serious. my budget is undecided.
Posted By: stevdart
Date Posted: December 09, 2005 at 7:09 PM
You're going to have a time finding a good amp match using three SVC 4 ohm subs. Wiring will be to 1.34 ohms, so you'd have to use a high current mono amp capable of servicing that load. With a 200 watt RMS per sub, you'd have to find a very small mono amp that puts out only 600 watts at 1 ohm. Consider these variables while you're at the drawing board. Look for DVC 4 ohm subs that will wire to 2.67 ohms and your selection of amps will be far greater. Let us know what you decide to go with...and use the woofer wiring help on this site as an aid. ------------- 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: j_darling2007
Date Posted: December 10, 2005 at 12:05 PM
If he wires 2 subs in series to get an 8-ohm load, and wires the 8-ohm load to the 4-ohm load in parelell to the 3rd sub, wouldn't that result in a 2.67 ohm load.
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There are 3 kinds of people in the world, those who can count and those who can't
Posted By: stevdart
Date Posted: December 10, 2005 at 1:08 PM
j_darling2007 wrote:
If he wires 2 subs in series to get an 8-ohm load, and wires the 8-ohm load to the 4-ohm load in parelell to the 3rd sub, wouldn't that result in a 2.67 ohm load.
Although the load on the amp would be what you state (8ohm paralleled with 4ohm), the power distribution to the individual subs would be totally whacked out. This diagram is essentially the hookup you described. (Note that with parallel connections they are the same whether connected directly to the speaker or directly to the amp, as same polarities are all connected): 
The amp would be outputting at a 1:2 ratio into the two different loads, into 8 ohms and into 4 ohms. The speaker on the right (#3) is a 4 ohm load so it would receive twice the power as #1 and #2 combined who together make an 8 ohm load. You can see the results with this example scenario: Say that the amp is rated at 500 watts into 4 ohms. You determine that it will output approximately 800 watts into a 2.67 ohm load. Ideally, you would want that 800 watts to be split evenly among the three subs for 267 watts each. The amp outputs 800 watts because it reads a 2.67 ohm load. But the power into sub #3 is twice as great as the power that is going into #1 and #2 combined. That's because 1and 2, as a wired set at 8 ohms, have an impedance that is twice as great as #3's 4 ohm impedance. So the power distribution with your proposed wiring scheme would be: - sub #1 = 133 watts
- sub #2 = 133 watts
- sub #3 = 533 watts
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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: j_darling2007
Date Posted: December 10, 2005 at 1:49 PM
Ok, that makes sense. I kind of thought something like that after I posted after I thought about it a little more.
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There are 3 kinds of people in the world, those who can count and those who can't
Posted By: reinkster
Date Posted: December 11, 2005 at 9:00 PM
this may sound stupid but can you flip any sub so that it sticks out of the sub box?
Posted By: arrow12
Date Posted: December 11, 2005 at 9:07 PM
Yep pretty much. Do a search for "invert" or "invert sub" and you'll get plenty of information on an inverted sub. You shouldn't have a problem though. Make sure if you keep one regularly mounted and one inverted, then you must make sure you keep them in phase.
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That's my opinion. Take it, leave it, or correct me.
Posted By: reinkster
Date Posted: December 11, 2005 at 10:42 PM
Any tips on fiberglassen a box? Things you would have done different or pics?
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