Altec A7 500-8 and Altec 1224A electronic crossovers

[GM]

Some locals had done it long before I got mine in '64 plus one even used Portland cement! Anyway, makes an audible difference to the point where I've periodically recommended mass loading them by adding removable weight for folks that don't want to/can't handle the weight.

That said, adding weight and/or Ductseal or similar to one of the bell hollows goes along ways towards damping the horn as well as the aforementioned speaker width baffle, preferably 24" high: https://www.homedepot.com/p/Gardner-...-110/100212441

Ideally, the horn box would be part of the bass cab, which it too needs mass loading if not heavily braced to make it rigid enough to 'ring' well above its pass-band: Audio Asylum Thread Printer

Align boring in the sense that to get a seamless match between the tapered horn throat and the tapered throat of the driver, a primary source of poor HF response easily seen in measurements, I obviously had access to a well equipped machine shop, so the horn's mounting flange holes were opened up a bit to ensure best alignment, then locked in place and an industrial grade adjustable brake alignment hone was used to perfectly blend the two together, adding alignment pins to ensure it stayed aligned.

For folks wanting to get the rated 22 kHz at a clean/audible [to some] output, this is a mandatory tweak.

[Lycoming680]

Some locals had done it long before I got mine in '64 plus one even used Portland cement! Anyway, makes an audible difference to the point where I've periodically recommended mass loading them by adding removable weight for folks that don't want to/can't handle the weight.

That said, adding weight and/or Ductseal or similar to one of the bell hollows goes along ways towards damping the horn as well as the aforementioned speaker width baffle, preferably 24" high: https://www.homedepot.com/p/Gardner-...-110/100212441

Ideally, the horn box would be part of the bass cab, which it too needs mass loading if not heavily braced to make it rigid enough to 'ring' well above its pass-band: Audio Asylum Thread Printer

Align boring in the sense that to get a seamless match between the tapered horn throat and the tapered throat of the driver, a primary source of poor HF response easily seen in measurements, I obviously had access to a well equipped machine shop, so the horn's mounting flange holes were opened up a bit to ensure best alignment, then locked in place and an industrial grade adjustable brake alignment hone was used to perfectly blend the two together, adding alignment pins to ensure it stayed aligned.

For folks wanting to get the rated 22 kHz at a clean/audible [to some] output, this is a mandatory tweak.

Very interesting. I was sitting on the couch last night messing around with my disassembled horn & driver components and thinking... Thumping around on the horn and dampening it in different locations.

I've got a few lathes and a couple of Bridgeport mills along with the rest of a machine shops goods and have no issue TIG welding cast aluminum. Are the horns aluminum or a pot metal of sorts?

Thanks,
-Brandon

- - - Updated - - -

GM - I ask about the horn material because I've got a few broken corners and wallowed out holes on the flange and wondered if they welded like normal cast aluminum or not...?

The boring, port matching and honing of the throats is exactly what I was thinking of, locating pins or stud sleeving to ensure alignment - yes, something along those lines. I really appreciate the input.
Thanks again,

-Brandon

[GM]

Always advertised as cast alum., for sure non-magnetic and have had them weld repaired with no comment from the welder.

511B sawed in half: https://www.hostboard.com/forums/hbm.../2013/01/9.jpg

edit: Note that I omitted the thick cardboard gasket, so if only wanting to fine tune it you'll need a metal spacer substitute, otherwise it's wasted effort performance wise.