New two-way ALtec horn design, questions

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.

**atilsley** · January 9th, 2013, 06:20 PM

YES....!!! Finally got the 416's today from Great Plains Audio.

Wonderfulyl packed...very professional.

They look absolutely fantastic....heavy, very well machined...just a piece of art.

I was keen to get them into their custom boxes...so, after only 15 minutes, I had them playing. What a relief.

Without run-in, they are sounding very good. The cabinets are around 160 liters, so bass extension is good, most likely getting a flat response to 40Hz, then gradual roll off. I'll check this on the weekend with my signal Hz CD.

Running the separate 100-watt pro amp to drive the woofers, with a 500Hz passive xover.

On the weekend, I'll disconnect this amp and run the drivers through the Bob Crites 500/5000 xover from the 300B SET...but I suspect I'll have to attenuate the horns down somewhat.

The tapped horn subs were hardly needed...but if I run the drivers with the 300B, I'll probably retain the subs.

The blue horns will go on sale so I can start on the 511/811/902 project.

**atilsley** · January 11th, 2013, 06:56 AM

Better pic attached.

Sounds better WITHOUT the solid state amp...now running all through the SET 300B. I need to attentuate the horns down 3 or 6dB. Subs are hardly needed.

**atilsley** · January 18th, 2013, 06:43 AM

Removed legs and sealed up the port to floor, then created another port on the front elevation, reducing size by 1/3. Greatly tighter and improved bass.

Also, tonight, I tested some miniDSP settings for the bass...adding low shelf rise to the 20-80Hz range by 6dB....plus used a Butterworth 24dB crossed 550Hz.....

Better filling of bass throughout the range...but probably too strong down low. Sounds more like a permanent sub woofer turned on.