[tomk415]

Hi

Looking for some advise in designing a custom speaker for my home theater system. Hopefully I will not make this too long, but I want to share as many details as I can so I get the right help. Thanks!

Current Set-up
LR speakers: Cambridge Soundworks MC 100
Center: Cambridge Soundworks Center Channel II
Surround: Cambridge Soundworks MC 50
Sub: Cambridge Soundworks Base Cube 8S
Receiver: Sony STR- DE675

This set up works well and sounds good for my needs.

Recently upgraded from a Sony 32" CRT to a 32" Samsung LCD. Picture is good, audio ok with some eq adjustments. My wife purchased a smaller cabinet for the tv and equipment that is more appropriate for our small home.

Anyhow, what I would like to do is build an LCR speaker that can be placed on the new stand. I would try to match the box to look like it is part of, or at least blends on with the new stand. The box also need to be able to carry the weight of the tv on top of it.

When I first set up the new tv, I put it directly onto the new cabinet. Adjusted the eq as needed and it sounded ok. Over the weekend I reconfigured my setup and added my LCR speakers. The tv is now placed on the center speaker. Since the Samsung speakers are down firing, the sound has changed quite a bit now that I raised the tv.

So to my question. I'm thinking I could build a new speaker cabinet that would hold my LCR drivers in one box, or at least what looks like one box. Paint it to match the to cabinet and it should blend it well. I'm also thinking of building one box that has roughly the area of a shelf/ tv cabinet top, so then I can get the ok audio back from the Samsung tv.

Exterior dimensions of the box, Max 26" Wide x 9" Deep x 4"high.

A couple of thoughts for drivers, etc would be to gut my CSW speakers and retro fit them into the new box, or just buy new drivers, etc. Would pref option one for cost reasons.

As I'm reading about speaker design it looks more complicated than I thought. Ports/ no ports. Interior area volume, etc. I don't want to make this too complicated, but I do want it to sound good. Thanks for your help.

Tom

 

[JCD]

There is a lot of flexibility to what you can do with DIY speakers, but you're hitting a hard one when you limit the height to only 4". Even your current speakers are closer to 5" -- and that's pretty short already. I think even if you were to increase the height to 5" you're still going to run into problems -- you won't be able to use the molded plastic that is being used with the CS speakers you've got, rather, you'd use MDF or baltic birch. The standard thickness used by most folks is .75" thick. Especially if you're going to be setting something with any kind of weight on it. So, of that 5" height, 1.5" is going to be eaten up by the materials before you even try to mount a driver in it. Also, speakers need a little bit of clearance as a general rule to sound best, so you don't want to cut the height to the absolute minimum..

If you want to cannabalize the speakers for a different enclosure, you need to be aware that the internal volume, driver layout and front baffle shape have been considered when the crossover was designed. Changing any of these variables is likely to have an adverse effect on the sound. I can't tell if they're ported or not either (I'm assuming they're not), but that could be another issue that would have to be addressed.

So, What I think I'm trying to say is that I don't think a single enclosure is what would work best for you, esepcially one so small. Or would ripping apart your current speakers and putting them back together in a new enclosure.

If you want to keep the size as small as possible, I think you would be best be served by building/buying only a TV stand and putting the l/r speakers on stands (or wall mount) them and wall mount the center.

If you want to go with some sort of DIY solution, you'll want to go with an already developed design. I'd look at the designs from:

• zaph audio
• Madisound
• Zalytron
• Parts Express
• Home Theater Guide

One really small speaker that I can think of is this one. At 9", it's about as small for DIY as I've seen.

I know this isn't what you're looking for, but it's the best i can think of.

 

[JCD]

Oh, and designing a speaker from scratch is not something to be taken lightly. If you want to do it right, there is a lot of work that you'd need to do before you even start. Not that it couldn't be fun -- I'm doing it and enjoy the process, but it's not something I'd recommend unless you're ready to invest in this as a long term hobby.