For me, it seems to make sense that I should use a cone driver in that ~150Hz-1kHz range...at least for now!
I was looking at the Eminence drivers (such as the Alpha 8 MR)...would these, or something similar be appropriate? I haven't really started looking yet, but even the used EV 12ML drivers are out of my range.
Another option is to possibly find old Guitar amps or PA speakers, and cannibalise the drivers - I suppose it would just be a case of research!
I was looking at the Eminence drivers (such as the Alpha 8 MR)...would these, or something similar be appropriate? I haven't really started looking yet, but even the used EV 12ML drivers are out of my range.
Another option is to possibly find old Guitar amps or PA speakers, and cannibalise the drivers - I suppose it would just be a case of research!
Those sealed back midrange drivers don't go low in a horn. The BC 8Pe21 will do that range very well - it's the big brother of what I have in my mid horn.
Hi,
Just finished the Bruce Edgar article. And went looking for the reason behind the diagonal corner reflector instead of the (horn) radius corner reflector. See page 14 showhorn article. The reflectors in the corners of a 90 degree bent need to be smaller than the crossection of the horn would predict. I found this paper by Bjørn Kolbrek about Modal sound propagtion in curved horns of rectangular cross-sectrion.
B&C has some interesting low Qes 8 inch drivers. I am probably gone use a Sica 8N2.5 or 8Fe2.5CP driver both not available in the US i reckon. +- 85$
Just finished the Bruce Edgar article. And went looking for the reason behind the diagonal corner reflector instead of the (horn) radius corner reflector. See page 14 showhorn article. The reflectors in the corners of a 90 degree bent need to be smaller than the crossection of the horn would predict. I found this paper by Bjørn Kolbrek about Modal sound propagtion in curved horns of rectangular cross-sectrion.
B&C has some interesting low Qes 8 inch drivers. I am probably gone use a Sica 8N2.5 or 8Fe2.5CP driver both not available in the US i reckon. +- 85$
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It's too weak of a driver for a horn, you wabt a total Q or QTS under .3
From Eminence I would choose this
Eminence Delta Pro-8A 8" Midrange 8 Ohm | 290-507 but still think B&C 8 is a better choice
You should download Hornresp program and model with the drivers, It's very accurate Hornresp
Ok.
Well, the Eminence is about $90 at the moment, and the B&C about $120. Celestion did have a driver with a similar Qts. I suppose that's the current price we pay for good midrange!
The reason I asked about Eminence is that their stuff usually crops up in Guitar amps (going back to the cannibalising method). Would this be a possibility with the B&C speakers also, or do they tend to float around as un-housed units?
Well, the Eminence is about $90 at the moment, and the B&C about $120. Celestion did have a driver with a similar Qts. I suppose that's the current price we pay for good midrange!
The reason I asked about Eminence is that their stuff usually crops up in Guitar amps (going back to the cannibalising method). Would this be a possibility with the B&C speakers also, or do they tend to float around as un-housed units?
Fs x 2 / Qes = roll off frequency
yes !!!!!!!!!
But you can go maybe 1/2 octave above this.
What crossover points are you choosing ?
still 150hz and 1khz ?
I'd use a pair of 8" per side.
Don't forget the B&C 8PE21 8" Midrange Speaker ($116) has horn mass corner almost 900hz.
150hz bass horn will be big.
remember floor loading isn't really 2pi.
It would be 2pi if the horn was mounted underground and the mouth was flush into the floor in the room you are listening in. Not a horn sitting on the floor.
So the mouth should be between 1pi and 2pi in size.
I'd expect 6ft2, maybe more.
A klipsch lascala has a too small mouth, and you can't do a folded horn because you are going up to 1khz. So don't cheat on the mouth size. See lascala's bumps at 260hz, 140hz then a falling bass response.
are you sure you want to horn load down to 150hz ?
Norman
here's my Alpha6A on a conical horn
here's a Peavey FH1 which is essentially like a 2 foot deep Klipsch Belle
here's one of my EV Sentry IV horns loaded with two pym1298 (~lilke Kappa 12A) vs a 1970's Klipschorn with CTS K33
one can vent La Scala per DJK's idea
assuming some amp power, a little 12" Karlson sounds more articulate to me than the FH1 setup like La Scala (K55V/Altec 500B, and APT150) - a 12" Karlson will hand 250 watt peaks with ~1/4" peak to peak movement.
If i didn't have these horns, I'd have room to setup my K15 Karlsons -
An externally hosted image should be here but it was not working when we last tested it.
here's a Peavey FH1 which is essentially like a 2 foot deep Klipsch Belle
An externally hosted image should be here but it was not working when we last tested it.
here's one of my EV Sentry IV horns loaded with two pym1298 (~lilke Kappa 12A) vs a 1970's Klipschorn with CTS K33
An externally hosted image should be here but it was not working when we last tested it.
one can vent La Scala per DJK's idea
assuming some amp power, a little 12" Karlson sounds more articulate to me than the FH1 setup like La Scala (K55V/Altec 500B, and APT150) - a 12" Karlson will hand 250 watt peaks with ~1/4" peak to peak movement.
If i didn't have these horns, I'd have room to setup my K15 Karlsons -
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Thanks Freddi, that is very usefull for reference (looking up TSP, dimensions and recalc to see if things add up).
I am using this formula to predict off-axis / coverage: minimum frequency of constant coverage = 23500 / (coverage angle in degrees * horn mouth width in meters).That's the reason i want to get my head around the use of multicel (or 2, 4 paths) in midbas horns. Like Klipsch and EV already do in their designs. Would a Sentry design improve if we add an extra vertical divider all the way along the horn lenght? Having a cross (+) as horn mouth has the extra benefit of plenty area to add felt to the mouth.
unaHm, another important part is voice coil induction in mH for the horn driver. This needs to be low too extend beyond the mass rolloff. Look up an typical subwooferbas voice coil induction mH and graph to get a picture of the effect of high voice coil induction. (same as a big coil in series with the woofer).
I am using this formula to predict off-axis / coverage: minimum frequency of constant coverage = 23500 / (coverage angle in degrees * horn mouth width in meters).That's the reason i want to get my head around the use of multicel (or 2, 4 paths) in midbas horns. Like Klipsch and EV already do in their designs. Would a Sentry design improve if we add an extra vertical divider all the way along the horn lenght? Having a cross (+) as horn mouth has the extra benefit of plenty area to add felt to the mouth.
unaHm, another important part is voice coil induction in mH for the horn driver. This needs to be low too extend beyond the mass rolloff. Look up an typical subwooferbas voice coil induction mH and graph to get a picture of the effect of high voice coil induction. (same as a big coil in series with the woofer).
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Thanks for the information Freddi!
Thanks also Phenoholic Anonymus - I think I need to get in touch with Bill (Fitzmaurice), as see what information he has beyond that SPL graph, in terms of how high it'll go. If the T18 CAN go to 300, then we're in luck.
I know it's not likely, but even though the KU 516 is expected to start rolling off at the low end around 300Hz, could it still be usable to 250? If we're looking at 12dB per octave, we'd lose about 4dB as it's about a third of an octave. It's a pretty big octave though!
Thanks also Phenoholic Anonymus - I think I need to get in touch with Bill (Fitzmaurice), as see what information he has beyond that SPL graph, in terms of how high it'll go. If the T18 CAN go to 300, then we're in luck.
I know it's not likely, but even though the KU 516 is expected to start rolling off at the low end around 300Hz, could it still be usable to 250? If we're looking at 12dB per octave, we'd lose about 4dB as it's about a third of an octave. It's a pretty big octave though!
I would not use the Monacor KU 516 beneath 500 Hz. Distortion sky rockets under 500 Hz. For this 500 Hz i would need a horn with a Fc of around 250 that's about the area of an 18 Inch round horn, 600 Hz 15 inch, 800 hz 12 inch diameter /or the equal area in a rectangle. Running a cheap compression driver so low works only with big expensive horns....
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Such as one of John Inlow's, or a Le Cleac'h from one of the popular manufacturers? I don't mind doing a bit of woodwork to get the frequencies I need!
Hi unaHm,
If you don't mind some woodwork maybe you can make a straight (cone) frontloaded bassmid horn. A compression driver is not going to work under 500 Hz, even the extremly expensive Goto bas mid drivers get mixed reviews used in larger horns.
Otoh, if you really like woodwork a Sato horn might be interesting. Crossover at 300 Hz, at least you would have a very attractive piece of wood art left if the compression driver won't load it You still would need a bass < 300Hz and a tweeter 3.000 > The Sato horn will give you a good impression how big a 150 Hz cutoff horn is.
If you don't mind some woodwork maybe you can make a straight (cone) frontloaded bassmid horn. A compression driver is not going to work under 500 Hz, even the extremly expensive Goto bas mid drivers get mixed reviews used in larger horns.
Otoh, if you really like woodwork a Sato horn might be interesting. Crossover at 300 Hz, at least you would have a very attractive piece of wood art left if the compression driver won't load it
You still would need a bass < 300Hz and a tweeter 3.000 > The Sato horn will give you a good impression how big a 150 Hz cutoff horn is.
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That sounds good to me! I'm not sure if the pun's intended or not though
I've started drawing the plans for the Sato horn on a big sheet of double-thickness cardboard that I have...mainly as a mock-up to see what the demands of construction are, but also as a template. I've seen that people have used masonite panels, dampened them, and bent them to match the curves of the horn walls...which sounds quite interesting to me!
I know that this question might be somewhat silly, but if I don't have a compression driver to use at the time, could I make some kind of whacky 'adapter' for a cone driver? My first guess is that the throat would be too small, but nothing ventured, nothing gained!
I've started drawing the plans for the Sato horn on a big sheet of double-thickness cardboard that I have...mainly as a mock-up to see what the demands of construction are, but also as a template. I've seen that people have used masonite panels, dampened them, and bent them to match the curves of the horn walls...which sounds quite interesting to me!
I know that this question might be somewhat silly, but if I don't have a compression driver to use at the time, could I make some kind of whacky 'adapter' for a cone driver? My first guess is that the throat would be too small, but nothing ventured, nothing gained!
Why not, if you use a 3,4 or 5 inch driver that can load the horn. Fs x 2 / Qes for your upper bandwidth frequency. And manage to keep the compression rate not extreme, cone sd > start of Sato. Try hornresp. Sato was half pun, i really like the looks of these horns.
If you construct your Sato wise, you keep room for of a cone driver. A bigger cone needs a shorter horn. There is room for this option in a Sato
If you construct your Sato wise, you keep room for of a cone driver. A bigger cone needs a shorter horn. There is room for this option in a Sato
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Sorry, I meant the pun in terms of what I'd said
As for using a cone driver, that's a relief - and I suppose with the 3-piece design of the Sato horn the final throat area of the horn can be changed depending on what you drive it with.
I'll see what I can find in terms of a suitable driver, and what hornresp says. Is it (the Sato horn) exponential, tractrix, or another type of flare? Sorry, I'm at work so I can't do much
As for using a cone driver, that's a relief - and I suppose with the 3-piece design of the Sato horn the final throat area of the horn can be changed depending on what you drive it with.
I'll see what I can find in terms of a suitable driver, and what hornresp says. Is it (the Sato horn) exponential, tractrix, or another type of flare? Sorry, I'm at work so I can't do much
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