Great guys.
I'm building a modified Frugal 3 (mouth and driver facing front). I was concerned with all the baffle step circuits being used on narrow baffles.
Still going to try Rl's and a wider baffle as I need a spacer anyway for the Pluvia Sevens.
Much thanks, Zene
I'm building a modified Frugal 3 (mouth and driver facing front). I was concerned with all the baffle step circuits being used on narrow baffles.
Still going to try Rl's and a wider baffle as I need a spacer anyway for the Pluvia Sevens.
Much thanks, Zene
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Generalised in the room given the wavelengths involved; as far as that particular aspect of what I was talking about goes, the mathematics are predicated on a free-space assumption and we don't live in free space, nor are our room constructions perfectly lossy, so in practice you rarely have as much effective attenuation at the listening position as the theory suggests. And then you also get the other points which I noted above.
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That isn't a modifed 'Frugel [spelling] 3'. That's completely at odds with all the design principles / assumptions used in developing the Frugel Horns, so you're entirely on your own. It certainly won't function anything like intended, the acoustic low pass will be severely compromised, as will the general response trend as the acoustic impedance match will be significantly compromised and the curve mis-sized. I wish you luck, but it's not a direction I'd advise. Out of interest -why do you wish to reverse it?
Scott ...
It will not be run full range. Both bottom and top will be cut off. Straight horns covering down to 100 - 200 hz are quite large. Even LaScalas with excellent upper-bass are 8 cu ft, so I thought a Frugel type horn just might work. Length is vertical, not horizontal as we know, so front firing could give me the mid-bass I desire.
I have plenty to work with for bass. Top will be augmented with tweeters so I can control volume. Old and upper frequency hearing loss come as a package deal.
Hate to say (not really), but doing what everybody else does, even though tried and true, does not advance the sport.
Zene
It will not be run full range. Both bottom and top will be cut off. Straight horns covering down to 100 - 200 hz are quite large. Even LaScalas with excellent upper-bass are 8 cu ft, so I thought a Frugel type horn just might work. Length is vertical, not horizontal as we know, so front firing could give me the mid-bass I desire.
I have plenty to work with for bass. Top will be augmented with tweeters so I can control volume. Old and upper frequency hearing loss come as a package deal.
Hate to say (not really), but doing what everybody else does, even though tried and true, does not advance the sport.
Zene
I have very rarely seen BSC used on FHs. We have never felt the need. Some people just like too much bass thou.
dave
A result pulled from observations of actual measurements by Olson & co of a limited number of shapes and given the dramatic roll-off of some shapes, it is only a first approximation.
dave
I'm less concerned with extension than the severe harmonic modes that will result through the upper bass and into the midrange (with rapidly increasing group delay) due to the severely compromised profile and acoustic low-pass, which in effect will be shifted at least 100Hz higher in frequency. If you want a front-firing horn, by all means use one -but I strongly recommend actually using one designed for purpose rather than trying to modify an enclosure designed for a completely different set of conditions.
Why anything other than sealed or a midTL for the P7 if it is being used as a midrange?
You build a FH to get bas sout of small drivers.
dave
You build a FH to get bas sout of small drivers.
dave
SM, after all these years that is point that I never considered. Yes, the fact that you are not dealing with a straight/flat response to begin with can be substantial.
For sure! Traditional free standing BLH design theory is for BSC and best to design nowadays using T/S theory.
All ... final score:
Wisdom 10
Speculation 0
Only major modification to the Frugel M3 will be the mouth. Cannot do curves. Goes together easily.
Simple IS better.
Great help guys, Zene
Wisdom 10
Speculation 0
Only major modification to the Frugel M3 will be the mouth. Cannot do curves. Goes together easily.
Simple IS better.
Great help guys, Zene
The curve is functional, so you'll be losing some performance without -I'd suggest you at least make a stab at it if at all possible. Speaking as a lousy woodworker, it's amazing what a little patience, a pre-drawn line / glued on template, a reasonably steady hand, jigsaw, and a hand-plane can do.
Scott ... I'll be cutting off around 80 - 100 hz, so thought makeshift mouth would be adequate.
Zene
Zene
Not ideal, as it's shaping across the gain BW; I'd still make the effort if possible. It should reap dividends, long-term.
Can do in 3 or 4 angles. As they will be seperate wings going to kick them out 10 deg to help with cavitation resonances.
Glad to know near full size will still be beneficial even with cutoff, thx.
Zene
Glad to know near full size will still be beneficial even with cutoff, thx.
Zene
Kick them out 10 deg? What cavitation resonances are you referring to? If you are altering the design of the terminus, you are altering the designed loading, and I can't predict whether it will work properly any more without knowing the details of your new design. The terminus will likely need to be reprofiled and the expansion path length / tap location and choke dimensions redesigned to suit.
SM, curious if taking the 2pi mean frequency loading of the vent, terminus areas and break down the curve into octave (expo) 'break' points same as done with other horns if it might be just as good or .........?
Zene, as Scott noted, basic skill with a jig saw should make simple work cutting the curved side panel. Indeed, several of “our” prototype builds were accomplished by rough cutting a 1/2” MDF pattern with jig saw, refining with belt and R/O sander. The plywood construction parts were also rough cut with jigsaw, then finished with pattern following bit on 3HP router.
As is often the case, every aspect of this deceptively simple design is functional, and to be honest, I found cutting the curves to not be the trickiest part of the build.
Of course, once satisfied with the protos, we proceeded with CNC machining of the side panels.
As is often the case, every aspect of this deceptively simple design is functional, and to be honest, I found cutting the curves to not be the trickiest part of the build.
Of course, once satisfied with the protos, we proceeded with CNC machining of the side panels.