New two-way ALtec horn design, questions

**atilsley** · January 6th, 2013, 04:35 PM

GM, thanks.

I now get the point re location of horn.

So, to simplify our discussion, I want to cross over at 1200. As such, is my project like a M19 albeit slightly taller?

With the 1200 xover point, is there any gain in going for the larger 511?

Oh, one other thing, I asked about ideal cabinet volume for the 416. Any thoughts? At present I have 160 liters, but with a rebuild, this can go to 240.

Kind regards

**rontec** · January 6th, 2013, 06:27 PM

Originally Posted by atilsley

Oh, one other thing, I asked about ideal cabinet volume for the 416. Any thoughts? At present I have 160 liters, but with a rebuild, this can go to 240.

Kind regards

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.

**atilsley** · January 6th, 2013, 08:13 PM

Originally Posted by rontec

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.

**rontec** · January 7th, 2013, 04:39 AM

Originally Posted by atilsley

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** · January 7th, 2013, 07:00 AM

Originally Posted by rontec

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 · January 7th, 2013, 11:28 AM

Originally Posted by atilsley

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** · January 7th, 2013, 04:59 PM

Originally Posted by GM

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** · January 7th, 2013, 06:10 PM

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** · January 7th, 2013, 08:33 PM

Originally Posted by 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...?

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.

GM · January 6th, 2013, 06:52 PM

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