Clip leads, plywood, and woofers, oh my

mred

Senior Member
My SLOB adventure is starting today
Inspired by NelsonPass and JC Morrison.
I am starting with two Altec 421 8 LF drivers, in a downward facing position into the slot much like JC's version with the big 30 inch
As they sit right now with bunch of eq and boost, it is not super deep and thumpy, but a very nice detailed addition. It passed the Lucy blind test this morning.
So now on to saw dust...

20190630_133310.jpg
 
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Looks like the 421s have been reconed as 416? Have you blocked the rear port? I missed out on a pair here in England a few weeks ago for £50, was kicking myself about that given how rare altec stuff is here!
 

Audionut

Next Round Is On Me
Tuned in!
If other altec 604 owners low end augmentation path are a sign, then I’ll be building sub enclosures in the near future too!
 

mred

Senior Member
Looks like the 421s have been reconed as 416? Have you blocked the rear port? I missed out on a pair here in England a few weeks ago for £50, was kicking myself about that given how rare altec stuff is here!
Good eye...
I cut out the metal dust covers and put on the vented ones
Yes taped off the magnet hole.
These are labeled Stanely Screamers and came in my 825 cabs.
 

gable

Senior Member
Ive been wanting to build one of JC's designs for LF. Stoked to watch along as you build these!
 

mred

Senior Member
After three12 plus hours work days I got some quality time with this cardboard mock up, as I might have listened for 30 minute when I posted it.
I am super stoked, this is the best match to my 825's I have had yet.
They blend really well together. That has been my issue with the other configurations I have been using.
Big smile and off to the garage to make more sawdust.
 

gable

Senior Member
Curious how you calculated the slot opening. If I remember correctly JC mentions in one of his posts that he aimed for 1/4 combined sd. I think Pass mentions 1/3 sd.

race for the bottom – lab jc

Not the exact style you're building, but same principle as I understand it. I'm very interested in your impressions of the finished product, as I would like to build one or two similarly as a 'sub' solution.

Now get to work and take plenty of pics! :D
 

mred

Senior Member
I have a wedge shaped chamber. 3 x 35 at the mouth is 1/3.
At the rear it is 1 x 35.Not sure how to calculate actual ratio, but I figure it is less than 3 to 1 .... should have paid more attention to the teachers in school. )
I have all my panels cut., ready to get out the joiner.
 

gable

Senior Member
That's about what I had calculated, back of the envelope. I think I'm going to try the vertical slot, wedge shape, 2 woofers on each side of the slot, maybe set their centers at an angle, somewhat emulating what JC did to get the diaphragm somewhat oblong shaped.
 

mred

Senior Member
That's about what I had calculated, back of the envelope. I think I'm going to try the vertical slot, wedge shape, 2 woofers on each side of the slot, maybe set their centers at an angle, somewhat emulating what JC did to get the diaphragm somewhat oblong shaped.
I went back and forth between this and vertical, if I had two more drivers it would be vertical.
I only got panels cut and shaped. Fitted up, got out the joiner and had to quit.
Cooking a nice dinner... smoked park chops.
If lucky I might get time Sunday.
 
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