I did a search and was not able to find the info, so please excuse me if this is re-hashing old stuff.
I picked up a single Altec A7-500 cabinet. The woofer is a 416-8B (it may have been re-coned at some point) and the top section is a 511 horn with a 802-8T driver. The network is a N501-8A and appears untouched. The cabinet is the 28 (?) model and appears to be factory built with the 5/8 stock material (definitely needs some bracing).
My questions.
1) I can't find what the specified DCR reading for the 802 driver should be?
2) The "horn" for the woofer seems short (I am used to folded horn designs). I can't imagine that it is providing much loading, certainly not at the lower end of the spectrum. Are there any graphs comparing the freq response of the stock "horn loaded" cabinet relative to a non-horn cabinet (comparable volume and venting)? IOW, how much is the horn loading contributing?
3) I suspect that the vent size (about 200 sq inches) is too large. By this, I mean that a smaller vent would give better and deeper lows (which were probably not a concern for movie theaters back in the day). I am guessing a vent about 1/3 to 1/2 as large as the stock vent. I am guessing since I don't know the computation for vent size when the driver is also horn loaded.
4) I notice that the cabinet could actually accomodate a much larger vent (up to 14 x 25 in). In other words, the cut out up front is much larger and a 5.5 inch board is slapped into place to leave about a 8.3 x 25 inch vent. Why was this done? Was it to allow for the cabinet to be tuned in the field, or to accomodate other drivers?
Forgive all my questions, but this is becoming an interesting project.
BTW, I do enjoy the dynamic sound of the cabinet. It could use a subwoofer (never my first choice), but I may first experiment with a smaller vent.
Thanks,
-Tom
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