AR.com DIY cabinet dimensions...and a question/suggestion

[dave_bullet]

Yes - sorry about the misleading post on the resistor to pad down the tweeter. I must pay "ohmage" to Ed for clarifying that (sorry - I couldn't resist that).

Anway - the good news is my AR.com DIY kit arrived from Madisound today (great service - 5 days from order to shipping and I live on the other side of the world!)

The question is - I have a project to build a CD bookcase.... or the AR.com DIYs - gee what should I start - easy choice really (CDs can just stay on the floor for a little longer :-)

I'm going to build the AR.com DIYs in a tower with a shelf in the middle to cut the volume the woofer sees to the planned size. (I'm tired of stands). I must admit - I'm impressed with the solidity of the tweeters. With excitement, comes some pride - so I'll be sure to post my pictures of construction along the way (somewhere....)

Cheers,
Dave.

[kexodusc]

I'm going to build the AR.com DIYs in a tower with a shelf in the middle to cut the volume the woofer sees to the planned size. (I'm tired of stands).

Dave, let me know how that turns out...I've already planned out my floorstander Ar.com's for my next project as soon as I'm finished the bookshelfs....just curious, what height are you using? I can't remember exactly, but I think I picked 26" height in addition to the 13" for an even 39". I read a few posts or comments where Ed's used 24" stands for them.

I've decided on a sliding shelf to allow me to fill the lower cabinet with sand or cat litter for loading.

I'm also thought about modeling a smaller ar.com using the Peerless 850108, 5-1/2" woofer for surrounds, but I might just cut down the cabinet depth and height a bit, and lose some bass response while keeping the 6-1/2" woofer to make them a bit more wall mount-friendly...they'd be cutoff at 80 Hz or so anyway by the processor/receiver. Save me from having to design a new crossover...we'll see...might be best just to build 2 more bookshelfs?

Good luck.

[dave_bullet]

I'm going for approx 35.5" high. I have a low couch and that height would put the tweeters at my ear level (which is usually recommended for floorstanders). eg. the top part of the cabinet will look exactly like a bookshelf AR.com DIY eg. 3" tweeter centre from top of cabinet, woofer approx 6mm from tweeter etc...

What I find hilarious is most manufacturers will make the lower end towers "shorter" to make their models through the range look bigger and justify the increase in price. If I made speakers......

PS: - don't forget to allow for feet in your tower design - these can be 1"+ if you use spikes

I like the idea of a shelf on an angle. Help break up panel resonances.

I notice with the Madisound kit they give you foam for the walls. Should you still stuff with batting / acousta-stuff? If it helps absorb unwanted midrange from escaping from the port - fine, but if it is just to make the box appear bigger for the woofer (which stuffing does by roughly10%) , I can do that by moving my partition down the cabinet.

Cheers,
David.

[kexodusc]

PS: - don't forget to allow for feet in your tower design - these can be 1"+ if you use spikes

I like the idea of a shelf on an angle. Help break up panel resonances.

I notice with the Madisound kit they give you foam for the walls. Should you still stuff with batting / acousta-stuff? If it helps absorb unwanted midrange from escaping from the port - fine, but if it is just to make the box appear bigger for the woofer (which stuffing does by roughly10%) , I can do that by moving my partition down the cabinet.

I'm not sure I'm qualified enough to answer you question. It would seem to me that you could get some undesireable effects from standing waves, etc if you increase the interior volume of the "top part" of the cabinet by dropping that partition. I know some people have made larger cabinets for these with poly-fill, acousta-stuff, etc, and reported good results. I think you would want to keep the 13 inch height the same, at the very least, and maybe use bracing every 8" or thereabouts to limit resonance problems. I wouldn't want to go much more than 13" without a brace.

After a few discussions with some other people last night I think I'm going to abandon the sand filling idea and just use 3 or 4 "donut" and "H"-braces in the lower cabinet to cut down on resonance. Might stuff it with pink insulation, poly-fill, or something cheap so there's no "hollow" sound.

[poneal]

Got all 5 boxes coated with the first coat of black gloss enamel. Dang they look good with just the first coat (I can see my self in them). I have to let them dry for 3 days then sand and put the second coat, wait 3 more days, then sand a clearcoat, then wait 3 more days, then compound, swirl remover, and glazing. Can't wait.....

[kexodusc]

Great so in 10 days or so you'll have some pics up for us, right?
Paul, what speakers do you own currently that you could give us a head-to-head comparison with when you're done?

Man, I can't wait to get back at this...moving company is coming on the 9th, hopefully by Monday, the 13th I can get back at them...