Altec 604 cabinet design considerations

[Elitopus1]

I would also find or make out of bolts, a 1/4" steel dowel and screw them into epoxy filled holes to locate the speaker.

Hey thats a good idea. It sucks holding a 30 lbs driver with one hand while threading in screws with the other hand. Having the studs there and then just using nuts is a good idea

[rogerh113]

Really compelling suggestion on the dowels and clamps. It really eliminates the tolerance stack-up that was building up close to the speaker cutout. Plenty of space and meat with the clamps (plenty far away from the edge). I went ahead and got the JBL MA-15 clamps. Pretty nice deal on eBay, and they look like an excellent choice. No need to keep fussing on that one.

Sounds like you recommend steel dowels rather than wood?? Is the concern not getting the speaker against the rear face of the baffle and snapping off the dowel?? Better safe than sorry, I guess...

regards -- Roger

[GM]

........then just using nuts........

.......then just using wingnuts...... and to make it easier still, make a wrench from plastic pipe. The one I use most is 3/4" dia. x 6" long with 3/16" x 1/2" notches. I started painting them dayglo orange when they began growing 'legs' and disappearing.

GM

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I went ahead and got the JBL MA-15 clamps. Sounds like you recommend steel dowels rather than wood??

Right, those or similar was what I was looking for. Surprised Google didn't find them for me.

Well, threaded rod in my case after finding out how hard it is to cut the drill blanks used for 1/24th scale slot car drive axles; but yeah, something I can drop heavy drivers on without worry.

GM

[Altec Best]

Hello GM,

Thanks for the info. Just to clarify my understanding of your terminology - you are suggesting running a 30 degree chamfer bit around the outside face of the speaker cut out, and then easing the edges. The start of the chamfer would be at .707 of the depth, so for example on a 1" thick baffle, the chamfer would start at approximately .3" in from the inside face of the front baffle, and extend outward at 30 degrees to the outer face.

regards -- Roger

My Altec 612C's came with that chamfered edge from the factory...

[VolvoHeretic]

Well, drawing #4.

604-8G Speaker Mounting-4.jpg

[rogerh113]

Hello,

Thanks for all of the input so far, things are very much coming together on the design. There are 2 more aspects that are not eminent, but useful for me to understand, and input would be helpful.

1) Speaker cloth / grills ?? I would guess that no matter how 'good' it will have an impact on the sound. I am in a situation where the speakers will be exposed to fairly bright, indirect light, so speaker cloth stretched across the face of the speaker would take the brunt of that rather than the cones. I have also heard (perhaps urban myth), that the grills will keep bugs and such out of the horn portion of the speaker. Insight appreciated.

2) Cabinet stuffing. Is there a clear winner in this category?? It seems that there are several popular ones. I assume they are all a bit different, so it probably matters. Perhaps application specific?


thanks again -- Roger

[Elitopus1]

My Altec 612C's came with that chamfered edge from the factory...

Someone is selling a 612c cab loaded with a 15" 515b woofer local to me. They have the woofer front loaded. The way the opening is cut allows this without the woofer or cabinet being modified right? Usually I see either the ribs are ground off the woofer or little slots are cut into the cabinet

[GM]

I'm curious too since I've never seen any factory flared cabs. Personally, I don't like the idea of mounting it on what is in effect a very thin 'baffle', so just used a file or grinder to rebate for the ribs. A bit of Silly Putty or similar in these grooves combined with a notched gasket seals well.

GM

[VolvoHeretic]

This is drawing #5.

604-8G Speaker Mounting-5.jpg

[GM]

Yeah, trim rings are real popular with the 'full-range' crowd.

GM