Speaker enclosures

 

New member
Username: Drummer87

Post Number: 8
Registered: Jul-05
Hi all, I'm making some speaker enclosures and need some clarification on some design points.
Keep in mind that what I'm working with are cheap salvaged drivers, an 8" woofer/mid(?) 3" mid and 2" tweeter and so precice sound quality isn't the biggest factor. And I'm a bit of a noob too :P

I was going to do a sealed design, no port, but wanted to keep the boxes rather small to fit nicely on my desk. I read that the right enclosure volume for an 8" woofer is 0.4 - 0.6 cubic feet.. now I can get 0.4 cu ft in my current sketch, but only if the mid/tweeter are in the same space as the woofer. Would that cause significant problems to sound? And how much does the volume of the enclosure effect the sound quality of the woofer (frequency response, etc. with significantly more or less volume/space)

Also, is it important to have the drivers and/or sound-coils vertically aligned? I really don't know what I'm trading off in designing these enclosures. While I'm no audiophile, I'd like to know of any significant changes in sound quality that may occur with certain enclosure designs.

I hope someone can help, even with the tinyest bit of information.

Many thanks, Owen.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 6516
Registered: May-04


http://www.madisound.com/

http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID=29


Both of these companies sell pre-assembled enclosures. Both sell books to help you understand the questions you've asked. Both also have some tutorials on building speakers. Start with these and see if you don't find it easier to buy what you want in an enclosure than build your own for generic speakers.


 

Silver Member
Username: Timn8ter

Seattle, WA USA

Post Number: 623
Registered: Dec-03
Getting the enclosure size right is the easy part as it's based on the electro-mechanical specifications of the woofer. The mid should be in it's own sealed compartment to avoid interaction with the back wave from the woofer. Tweeters are usually sealed so that's not a problem......HOWEVER........
It's all for naught if you don't design a good crossover and 3-way crossovers can be a rather daunting challenge to get right.
 

New member
Username: Drummer87

Post Number: 9
Registered: Jul-05
Thanks for those links... I would like to get some proper, decent speakers to go with my NAD reciever, and do it justice, but I'm a student and have absolutely no money at the moment :-(
Does this design look ok with the mid/tweeter in their own compartment? and the arrangment of the drivers?
http://img306.imageshack.us/my.php?image=speakers3ko.gif
 

New member
Username: Drummer87

Post Number: 10
Registered: Jul-05
bump?
 

New member
Username: Kidstereo

Post Number: 7
Registered: Oct-05
Where'd you salvage the speaker drivers from, the Titanic? LOL. j/k. But seriously, where'd you find those speaker drivers, because whenever I hear or see the word "salvage," I tend to think of somebody diving down to a sunken ship or boat and taking something from it.
 

Bronze Member
Username: Drummer87

Post Number: 11
Registered: Jul-05
lol.. I picked them up during a council clean-up, just from someone's lawn. They had cases, but they were all swollen from the wet and looked overall cosmetically dismal. Now I have 3 of the speakers out of their box, just sitting on my bedroom floor and the other 3 still in their box but with the back removed. Both are still hooked up to my amp as well, and the left channel is much louder than the right :-(

I want to make smaller cases for the drivers so I can put them on my desk (old cases are 58cm high). I'll eventually get some good speakers, but these will have to do for now as I have no money and things higher on my list of things to buy when I get money.
 

Silver Member
Username: Timn8ter

Seattle, WA USA

Post Number: 636
Registered: Dec-03
What are you doing for a crossover?

Do you have the make/model of the woofer?
 

Bronze Member
Username: Drummer87

Post Number: 12
Registered: Jul-05
Just using the crossover that was in there. All the drivers are made by Sharp, and the crossover is just a simple one.. 3 caps, 2 coils and a resister.
 

Silver Member
Username: Nuck

Parkhill, Ontario Canada

Post Number: 319
Registered: Dec-04
Tim, the XO being daunting, I have been looking at sites for just a decent 2-way, and I am having problems digesting what I am looking at.
I got some new, cheap componants(almost free) and will try a set of speakers.
Any links to info(XO) and other for a guy with the minimun recommended daily allowance of intelligence and ability?
 

Silver Member
Username: Timn8ter

Seattle, WA USA

Post Number: 639
Registered: Dec-03
Owen:
If you're going to use the stock XO you should also keep the cabinet very close to the original. Reducing the size of a vented cabinet usually results in creating a bump in the bass response before the roll-off which can sound pretty bad. If you're set on a smaller cabinet you could try a sealed box. That may allow you to get away with something smaller but with a loss of bass extension. You may be able to get away with a minor change in the cabinet size (say 10-20%) and not suffer disasterous results.

Nuck:
There are some free on-line XO calculators. This can get you started but keep in mind that any tool like this is going to be a rough estimate at best.
http://www.ajdesigner.com/crossover/crossoverfirst.php

http://www.the12volt.com/caraudio/crosscalc.asp

To really do this right requires proper measurement equipment but if you've got the willingness and patience to go through the trial and error process then go for it!
In order to get an idea of proper cabinet volume you need to know the Thiel/Small parameters. If you have those you can use WinISD.
http://www.linearteam.dk/
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