Corner speaker for 604

**LICORNE** · February 5th, 2009, 12:23 AM

For those interested in this model ,here is a good site to look at.

http://www.wardsweb.org/Billfort/

........................................

**Horn Savant** · February 5th, 2009, 03:29 AM

"Lowther rear horn loaded speakers."

I've heard these at shows - sounded very fine, but am skeptical of the value of rear horn loading. More interesting to elimate speaker backwave and front horn load.

You could also add a 511 horn+driver and use 604-8G tweeter as supertweeter. Easy to find because 511 horns never die, they just keep on being resold & recycled from one experimenter to another.

**wws944** · February 6th, 2009, 01:44 AM

I have looked at the billfort page on a number of occasions, while considering a set of GPA 604s.

But what to do if one also wants a center channel for HT? Isn't it desirable for the centers of the three drivers to be at the same height? With the billfort cabinets the driver centers are at 38" and the top of the cabinet is at 48". Which means the screen/display would probably be too high on the wall?

Would it be better to use a slightly smaller 606-like cabinet (roughly 7.5 cu ft), and keep the driver centers closer to the floor? The driver centers are more like 24" off the floor, and the top at 36" - which seems more managable when thinking about a center channel cabinet...

Room size is 13' wide by 28' long, with normal 8' ceiling. Listening/viewing position is about 12' from the wall.

One other question: why are there so few corner cabinets these days? Are there technical reasons against them? I have to admit I like their looks.

Any advice from the pros appreciated!

GM · February 6th, 2009, 02:21 AM

Originally Posted by wws944

Isn't it desirable for the centers of the three drivers to be at the same height?

Would it be better to use a slightly smaller 606-like cabinet......?

.......why are there so few corner cabinets these days?

Yes.

Best to use a separate LFE system, so the mains only need to be just big enough to handle an 80 Hz XO.

Corner loading maximally excites the room modes, so a stereo pair creates strong peaks/dips in the response that aren't easily resolved in a typical rectangular room.

GM

**LICORNE** · February 6th, 2009, 07:47 PM

Long rectangular rooms are not ideal for floor models. Best to use wall mounted speakers.
Even if it means using a smaller cabinet.

The 604 in a 612 cab still is considered huge for wall mounting . To bad 12" under hang voice coil light weight cones are not available.

...................................

**bfish** · February 6th, 2009, 10:28 PM

Originally Posted by LICORNE

...To bad 12" under hang voice coil light weight cones are not available.

Aahh, but they are;

http://www.greatplainsaudio.com/downloads/212_8A.pdf

**LICORNE** · February 6th, 2009, 10:40 PM

Alleluia B Fish . GPA has just solved the longest problem with those long rectangular rooms in the home entertainment industry.

Some of these rooms had tall windows on one side . Just imagine the task.

Thanks for the info.

**bfish** · February 6th, 2009, 10:52 PM

De rien

**wws944** · February 9th, 2009, 12:52 AM

Originally Posted by GM

Yes.

Best to use a separate LFE system, so the mains only need to be just big enough to handle an 80 Hz XO.

Corner loading maximally excites the room modes, so a stereo pair creates strong peaks/dips in the response that aren't easily resolved in a typical rectangular room.

GM

GM, thank you. I appreciate your answers.

I looked at the 212 specs at GPA. Does that massive frequency dip/peak between 10 and 15khz mean that it really needs a separate tweeter? Or is it something that a good crossover could deal with instead? (Not sure I can hear 15khz very well anymore anyway. One of my TVs 15khz is quite audible to the kids, but not so much to me.)

GM · February 9th, 2009, 01:35 PM

You're welcome!

Due to our poor hearing acuity down low and up high where we tend to only key on amplitude peaks combined with generally little/no useful content in recordings above ~12-14 kHz, I seriously doubt it's a big deal to even youthful hearing unless they're musicians that play instruments with significant HF harmonics such as the violin. For those that are though, a notch filter to knock down any extreme peaking should solve the problem, though the components will probably create another that may be audibly worse overall, so Caveat Emptor applies. Note too that this peak may flatten out off axis, so proper vertical baffle placement and/or toe-in positioning may be the passive acoustical solution to the 'problem'.

GM