My Frugel-Horn Build

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Re: Frugel "stealth" woofer

chrisb said:
To follow up on above post, for those interested, Dave has modeled the SDX7at about 21 liters for this application - which is approx 3x the cubic volume of the original deflector design.

A full height triangular deflector, 310mm on each side and 380mm on the back, with some cross bracing would nicely accommodate one driver per side.

Outboard amp(s) make the most sense.


Yeah, dave had suggested those to me earlier. That's what I think I'll go with but I think I might wait a bit just because I don't want to drop too much money on this at once.

21 liters works out to about .74 cubic feet. I could hide that for sure. Just so I know I understand you correctly, the deflector needs to be a triangular (isosceles) prism with the congruent sides at 310mm and the hypotenuse as 380mm. Full height is 542.3mm right?
 
Re: Re: Frugel "stealth" woofer

italynstylion said:



Yeah, dave had suggested those to me earlier. That's what I think I'll go with but I think I might wait a bit just because I don't want to drop too much money on this at once.

21 liters works out to about .74 cubic feet. I could hide that for sure. Just so I know I understand you correctly, the deflector needs to be a triangular (isosceles) prism with the congruent sides at 310mm and the hypotenuse as 380mm. Full height is 542.3mm right?


Actually, "full height"' refers to that of the main cabinet - i.e. approx 773mm - the extra 230mm is where much of the additional cubic volume is gained. Since it hides behind the main enclosure, and in your case, supra-baffle, I'm sure the size difference wouldn't be a big issue.

I fully understand that once you get so much of the wide-band done well, as the FH or other "full-range" can achieve, the cost of additional driver(s) and amp(s) to fill in the bottom octave or so can seem more than a bit disproportional. That's one of the reasons why I've quite happily adjusted to "life without woofers"
 
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Re: Re: Frugel "stealth" woofer

italynstylion said:
21 liters works out to about .74 cubic feet.

21 liters gives a modeled Q of 0.5 with no stuffing. Because they will be facing into a corner (or at least a wall) they will get maximum room gain. So i'd tend to build for a slightly smaller net volume, put the driver at the floor, and add an increasing density of damping as you approach the top. the damping will increase the "apparent" volume.

It is important that the angles of the triangle be maintained. Attached is a 1st pass...

dave
 

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well, my initial sketch came out a bit deeper, but that was based on 19mm (3/4") material - with 12mm (1/2") a lot of bracing would be required - this driver can create more internal pressure than an FE126E

anyway, y'all get the idea

we should prolly build a pair before August?
 
frugal-phile™
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chrisb said:
well, my initial sketch came out a bit deeper, but that was based on 19mm (3/4") material - with 12mm (1/2") a lot of bracing would be required - this driver can create more internal pressure than an FE126E

anyway, y'all get the idea

we should prolly build a pair before August?

I just used 12mm because it was already in the drawing.. it should realley be 18mm BB or -- like in Tysen -- 2 x 12mm. The SDX7 sealed moves a 12mm panel pretty good.

I'd run 3 braces top to bottom, with a full "height: holey brace around the woofer and then smaller braces from that to the front sides.

dave
 
Those plans look great. That would be a much easier build. I calculated the volume based on the sketch and came up with an internal volume of .954 cubic feet or about 27 liters before driver and bracing displacement. Is that correct? Is it intentionally large because of driver and bracing displacement?

When I have an extra $200 I'm going to give this a shot. My birthday is coming up in April. :D
 
I wanted to bump this thread.

It's been almost a year since I last ran the Frugal Horns. I'm guilty of neglect in the worst sense. I've been working on so many other designs these have been collecting dust. I decided to connect these today and I'm glad I did.

I had forgotten just how well these image. I'm constantly hearing things that I didn't know were in pieces of music I know VERY well. My favorite tonight was the harp in the Ray Lynch track Celestial Soda Pop. You can almost feel the tension in each string as it's being released. The separation is incredible.

I suppose this is what happens when very special drivers end up in well designed cabinets. I really need to finish out this design with the rear deflector. I know I'd planned to do it last year but it kept getting bumped off my list.
 
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