New two-way ALtec horn design, questions

[atilsley]

Another consideration in building new cabs....the 511b will require a minimum of 24". Using the 811b you can narrow the cabs another 5"-6". I prefer the 511b in larger rooms but regardles of which horn I would focus much effort on EQ ing the horns(a tip from GM in the past). IMO this is where the mod.19's crossovers came in to play and were so responsible for that great sound! (love to hear the GPA's too) However, as GM pointed out phase alignment may suffer a little with the 511b. A crossover mod could help though.

Thanks...my existing cabs are 24 inches deep...so I'm ok there. When you say you prefer the 511 horn in larger rooms, what do you define as a large room? My listening room is an open lounge/family...approx 20 feet x 14 feet, then opens up bigger. Ceilings are tall also, 11 feet. Distance from audio to seating is 16 feet.

[atilsley]

You’re welcome!

Again, if using the GPA XO, then only if you use an 811 in the same location referenced to the woofer location.

I already answered this and don’t know how to explain it any simpler, so with what few details you’ve posted, I’m guessing not in your app.

Huh?! I gave you my thoughts! Guess I gave you too many, so if 240 L is as big as you can go, then do it and initially tune it to ~32 Hz and fine tune it from there if required.

GM

Thanks again, GM...I'm trying to keep up with your tech detail...so it's all a learning for me at the moment. I appreciate you've been in the game a long time.

As an aside, for your own system (or previous ones), do you run any subs? I ask this because I have the two small tapped horns I can use for the 20-40Hz range if needed. For me, I guess I'm working through the issue of building an Altec system that is strictly two-way (ie, no subs), or with subs. If the latter, then I don't need to tune the cab down as low, hence, not build it as big. Just talking out loud here....

Thanks again.

[atilsley]

No experience with any of the Altec/GPA adjustable XOs beyond playing with settings on some Altec consumer model speakers and not liking what I hear when any 15? is used this high with a separate horn, no desire to get any.

GM

Thanks....just to clarify your point, are you saying you do not like the sound of a 15-inch woofer approaching/exceeding 1200Hz? Does this mean you do not like the sound of the Model 19, which crosses over at this frequency?

I'm just asking as the Model 19 is something I'm trying to determine if that's the 'sound for me.'

Kind regards.

[mah]

Anybody near Sydney got a Model 19, or similar, for auditioning by Atilsley?

[rontec]

Thanks...my existing cabs are 24 inches deep...so I'm ok there. When you say you prefer the 511 horn in larger rooms, what do you define as a large room? My listening room is an open lounge/family...approx 20 feet x 14 feet, then opens up bigger. Ceilings are tall also, 11 feet. Distance from audio to seating is 16 feet.

I think 511b's could work well in this sized room. The 24" I mentioned is the minimal width of the cabs being that the 511b's are about 23" across. Again if you're keeping the cabs as narrow as possible.

[atilsley]

I think 511b's could work well in this sized room. The 24" I mentioned is the minimal width of the cabs being that the 511b's are about 23" across. Again if you're keeping the cabs as narrow as possible.

Ok thanks. The HF's are similar for 511 and 811....given I'm aiming to cross higher, wouldn't the 811 be the default choice? Obviously, if I was building a VOT A5/7, the lower xover point would make this horn choice more critical.

[GM]

Distance from audio to seating is 16 feet.

Just so we're all on the same 'page', for horn design [polar response] selection it's the 'line of sight' distance, so depending on how wide the 'sweet spot', the 511 may be preferred in this app.

GM

[atilsley]

Just so we're all on the same 'page', for horn design [polar response] selection it's the 'line of sight' distance, so depending on how wide the 'sweet spot', the 511 may be preferred in this app.

GM

Thanks.

If I went with the 511 and dropped the notion of the GPA adjustable two way N1200 xover, what would your preferred xover point be? (assume I will use the 902 comp driver and have bass cabinet of 240 liter.)

Yes, I'm asking for personal opinions.

Thanks very much.

[rontec]

I thought GM was saying you could still use the 1200 xover with the 511 , but you might need to physically move the 511 a few inches forward into the listening room so to more align the voice coils of the woofer and HF driver again to maintain a closer phase alignment...?

[atilsley]

I thought GM was saying you could still use the 1200 xover with the 511 , but you might need to physically move the 511 a few inches forward into the listening room so to more align the voice coils of the woofer and HF driver again to maintain a closer phase alignment...?

Thanks...yes, I understood the point about moving the horn to get the optimum alignment. My q was more around the bass driver running up to 1200Hz...as GM had made a comment earlier that he wouldn't like that....hence my q to him about the Model 19, with the 1200Hz xover point.

Kind regards.