Has any had any experience with push pull lowther (or other similar FR) driver horns.
I suppose Lowther has made a number of examples (TPI, Isis, Opus etc.).
I'm specifically thinking of something like the Azura example with a tractrix or spherical of JMLC front horn and an exponential bass horn for the back wave of the driver.
It seem like Martin has put one together called the AH-PP2 (bottom of page):
Azurahorn -Le Cleac'h Acoustic Horns - Products
And that Pnoe with AER is now using some sort of waveguide or horn:
AER | pnoe
Similarly, the bauhorn virtuoso had a small front horn.
Any insights on the pros/cons, both technical and sonic, would be greatly appreciated.
Thanks!
I suppose Lowther has made a number of examples (TPI, Isis, Opus etc.).
I'm specifically thinking of something like the Azura example with a tractrix or spherical of JMLC front horn and an exponential bass horn for the back wave of the driver.
It seem like Martin has put one together called the AH-PP2 (bottom of page):
Azurahorn -Le Cleac'h Acoustic Horns - Products
And that Pnoe with AER is now using some sort of waveguide or horn:
AER | pnoe
Similarly, the bauhorn virtuoso had a small front horn.
Any insights on the pros/cons, both technical and sonic, would be greatly appreciated.
Thanks!
They're generally called compound horns. Sometimes useful, sometimes not. Depends on the specific goals & equipment.
A back-loaded horn (bass horn) is like any other back loaded enclosure: it's only useable over a relatively narrow BW. Above a certain point that is a function of the axial length, group delay becomes excessive. Hence the reason most have an acoustic low-pass. However, if the maximum practical corner frequency occurs below the system's effective mass-corner frequency (2F0/system Q), you either need to put up with a hole in the amplitude response between these two points, use digital EQ to compensate, or use a short midrange front horn to provide gain that will 'fill in' the gap.
A back-loaded horn (bass horn) is like any other back loaded enclosure: it's only useable over a relatively narrow BW. Above a certain point that is a function of the axial length, group delay becomes excessive. Hence the reason most have an acoustic low-pass. However, if the maximum practical corner frequency occurs below the system's effective mass-corner frequency (2F0/system Q), you either need to put up with a hole in the amplitude response between these two points, use digital EQ to compensate, or use a short midrange front horn to provide gain that will 'fill in' the gap.
yes, but gosh, those Axjets are actually quite organic and almost sensual looking - not in a Georgia O'Keefe way-- or, maybe ...
The closest thing I've ever heard to a compound horn would be a Tannoy Westminster - sorry, but my ears couldn't get past the choking sound of my wallet. Devices of this stature are certainly benchmarks of sorts -and it's hard to deny the visceral impact of a system capable of effortlessly delivering " realistic playing levels" - and few of those without imparting their own personality, but when does the fiscal extragence cease?
Of course, what am I thinking - nothing succeeds like excess - just ask DJT
The closest thing I've ever heard to a compound horn would be a Tannoy Westminster - sorry, but my ears couldn't get past the choking sound of my wallet. Devices of this stature are certainly benchmarks of sorts -and it's hard to deny the visceral impact of a system capable of effortlessly delivering " realistic playing levels" - and few of those without imparting their own personality, but when does the fiscal extragence cease?
Of course, what am I thinking - nothing succeeds like excess - just ask DJT
Thanks all. I didn't know they were even called compound horns, so found nothing on my first attempt diyaudio search.
I still don't see why some of the Lowther based systems would use such a large flh (e.g. a 160hz tractrix). Seems like the gap between the acoustical roll off and the baffle step (which I assume is what we are filling in; and that the difference between acoustical roll off of the blh and mass roll off of the Lowther give you a wide latitude to do this) have to be higher.
Is it motivated by a kind of sledgehammer approach, i.e., that it would be worse to undersized the flh and therefore create a larger perceived gap over a narrower frequency band (between a higher sensitivity blh to a gap to a higher sensitivity mid horn with too small a mouth to full bridge)
Simply put, is it less lumpy to oversize the flh given the obvious complexities of correctly simulating the two horns?
I still don't see why some of the Lowther based systems would use such a large flh (e.g. a 160hz tractrix). Seems like the gap between the acoustical roll off and the baffle step (which I assume is what we are filling in; and that the difference between acoustical roll off of the blh and mass roll off of the Lowther give you a wide latitude to do this) have to be higher.
Is it motivated by a kind of sledgehammer approach, i.e., that it would be worse to undersized the flh and therefore create a larger perceived gap over a narrower frequency band (between a higher sensitivity blh to a gap to a higher sensitivity mid horn with too small a mouth to full bridge)
Simply put, is it less lumpy to oversize the flh given the obvious complexities of correctly simulating the two horns?
Well, not speaking for other designers, but I found that the larger the fronthorn I built, the better my Lowthers sounded. Regardless of my decent midbass horns that could easily take over anywhere I needed them to. Crossovers can be done right, but the further away from the midrange, the better. The easier I guess. The apparent size of the sound image got bigger, sound was smoother and more authority. Harmonic structure seemed better. I loved the cello on the bigger horns etc. But the bigger/the deeper the horn, the less treble and more beaming. Basically your endless set of trade offs.
I concur with Ivo, best luck i've had so far with lowther types, has been a large front horn
(160 Hz Lecleach, with AERs), with a modified Karlson 15 crossed in ~200Hz.
The big, short, fast opening Azura isn't as dark as the smaller horns.
Great center image, instruments are where the belong, clean vocals...
I tried, numerous backhorns (Austins, etc), modded some into compound horns, & gave up on backhorns. never could get the back wave to "match" the front wave.
(160 Hz Lecleach, with AERs), with a modified Karlson 15 crossed in ~200Hz.
The big, short, fast opening Azura isn't as dark as the smaller horns.
Great center image, instruments are where the belong, clean vocals...
I tried, numerous backhorns (Austins, etc), modded some into compound horns, & gave up on backhorns. never could get the back wave to "match" the front wave.
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