Internal damping for BAMTM

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Good afternoon all,

First off my thanks to J.Kretke for the Zaph BAMTM design. It is my first DIY project and I've had a great time doing it. Quite the learning curve for me, I assure you. I chose it after a couple months browsing around the internet looking for a good set of speakers. My original plan was to get some replacement parts for my B&W 601 S3's which my brother so handily blew up. *sigh*. But after coming across DIY ideas I thought I would be better off and have more fun if I did it myself. Enter the BAMTM.
...something told me to order more than 2 front baffles. LOL. Turns out the tool I have for hole cutting is less than accurate. (Router Zip) And can not make holes smaller than "around" 4 inches. So $60 in PE baffles later I've finally got it right. (Will post pics when I get the 2nd speaker done completely.)

First off I can tell you that compared to the B&W's these BAMTMs outshine them in terms of clarity in the high and mid-high range. Which is saying something imho as the B&W's were great. One has to put a bit more power in them but that is to be expected. These speakers really sound good! (And their quality of reproduction really pointed out how many bad recordings I have.-gonna have to step up to only lossless encoding for my music now!) Vocals and alto-tenor instruments sound amazing. Anyway, I am now trying to fine tune them.

I've really had a tough time getting the internal stuffing right. John mentions on the BAMTM site that 1/2 pound (or so) per box will work. But trying this as the only stuffing (in the rear compartment behind the woofers on the PE 1.0 box) left the music boomy and receded/distorted sounding, Like a clock radio turned too loud in the next room. I figured I left some key element out which wasn't mentioned in the page yet folks know to be critical as a rule and which I do not. So after some more reading I decided that I needed to line the walls of the enclosure inside. I got some 1/2 inch and 3/4 inch foam and lined all the internal walls. Result: too much. Bass sounded swallowed and like a single note. Removed the foam from the sides of the rear compartment and a little of the Acusti-stuff from between the woofers in the front half. Mids became better and bass became more forward and much tighter. But here is the thing. I am getting some kind of interference/distortion in the midrange and some of the highs are a bit too "essee" like they really jump out and attack your ears . I like that clarity but was wondering if I could dampen some part of the internals, or if there was a rule of thumb I am not following when damping sealed enclosures.
Or could it be this: I mounted the crossover on the internal bracing divider in the box which means the inductor for woofer is only about and inch or two from the magnet of one of the woofers. Will this cause interference?

Sorry to be so verbose. It's a curse I bear constantly. heh heh , and thanks in advance for help and suggestions all.

Best,
Daryl
 
All,

Disregard the comment on the boomy, receded, clock radio comment. That was because I had some leakage in the baffle. It also could have been some faulty wiring. I some new 18 gauge wire and re-made the crossover. I wasn't clear on when I was having that issue in my original post. Perhaps I should interject here that whoever attempts to make these that as with all things audio: Do it PRECICELY. Don't mean maybe here, that little bit of invisible air coming in around a slightly off rout job WILL make a big difference. (this we know, but be certain all your angles and measurements are right on.)
These are great speakers with great sound. .. and on that note looks like I'll be needing to upgrade the amp. These speakers are better than my old Sony can handle. I will hook them up to my Marantz HT receiver as a reference, but I want to use these soley for music and so I think (budget minded as I am) that I will make a DIY project out of building a gainclone. Good match? ...then again that Behringer A500 looks sweet too...

Still interested on stuffing/lining comments for fine tuning.

Cheers.
Daryl
 
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