I'm playing a lot with F.A.S.T. project for a while, and i was wondering about the ''C.A.S.T.'' alternative, where the Fullrange driver is replaced by a Compression driver...
In my case, that would be hornless, as discussed in that thread
http://www.diyaudio.com/forums/multi-way/300628-official-hornless-compression-driver-thread.html
But of course one can use a short horn as well.
In both cases i think the use of an DSP/EQ is mandatory; massive gain adjustements will be needed, steep xover slope, EQing, etc...
I didnt try it yet, but i think it might work good. Not quite sure about the upper end though, because the only CD that are going low enough (400-500hz) are most of the time the larger 4'' diaphragms, and they might not be at their best @ 10khz+ but still, i think we can get something pretty decent on 9 octaves, with extraordinary undistorted potential SPL output 😱
Also, the less expensive option (and maybe a better sounding one?) would be to use a 3'' diaphragm (2'' throat) along with a subwoofer that still in his comfort zone around 700-800hz, like the TIW250XS or the 8W1v3...
Food for thoughts!
In my case, that would be hornless, as discussed in that thread
http://www.diyaudio.com/forums/multi-way/300628-official-hornless-compression-driver-thread.html
But of course one can use a short horn as well.
In both cases i think the use of an DSP/EQ is mandatory; massive gain adjustements will be needed, steep xover slope, EQing, etc...
I didnt try it yet, but i think it might work good. Not quite sure about the upper end though, because the only CD that are going low enough (400-500hz) are most of the time the larger 4'' diaphragms, and they might not be at their best @ 10khz+ but still, i think we can get something pretty decent on 9 octaves, with extraordinary undistorted potential SPL output 😱
Also, the less expensive option (and maybe a better sounding one?) would be to use a 3'' diaphragm (2'' throat) along with a subwoofer that still in his comfort zone around 700-800hz, like the TIW250XS or the 8W1v3...
Food for thoughts!
Big pro of the CAST: you can use only ONE chamber enclosure. No need to worry about the fullrange's isolation from the subwoofer. Also, the neo CDs are usually very compact.
Altogether, you probably can achieve amazing SPL per liter of enclosure. Very compact, very powerful, easy enclosure construction, at least 9 octaves.
Altogether, you probably can achieve amazing SPL per liter of enclosure. Very compact, very powerful, easy enclosure construction, at least 9 octaves.
BMW 4592ND, 4593ND, 4594ND, 4595ND are all coax CD from BMS
exit throat variations and maybe other specs
List is here: Neodymium Compression Drivers
exit throat variations and maybe other specs
List is here: Neodymium Compression Drivers
I would use some type of shallow waveguide no matter what. The Dayton 8" round guide comes to mind or a bit harder to find, the Denovo 6"
The BMS coax compression driver kicks butt
JTR uses them for their 228 to 215 series of theater speakers and cross them at around 360Hz or so. Danley Sound Labs also uses them for their Synergy Horns used in stadiums. From what I recall, they cross over at 7KHz to the smaller compression driver so a great option
Literally, you could use a 18 to 21" woofer to make a "full range" box by crossing it at 400Hz and it looks like a "two-way". Very expensive part, they run $700 and up for one not including the horn or passive crossover.
I'd love to mess around with that unit, calculate the cost of the drivers, proper passive crossover and proper horn and you are approaching $2,000...then add the cost of an 18" woofer, birch ply to build a large box etc. etc. etc. You had better be on top of your game with the costs of the BMS, I'm not worthy so I sit on the sidelines and dream...
Good luck!
JTR uses them for their 228 to 215 series of theater speakers and cross them at around 360Hz or so. Danley Sound Labs also uses them for their Synergy Horns used in stadiums. From what I recall, they cross over at 7KHz to the smaller compression driver so a great option
Literally, you could use a 18 to 21" woofer to make a "full range" box by crossing it at 400Hz and it looks like a "two-way". Very expensive part, they run $700 and up for one not including the horn or passive crossover.
I'd love to mess around with that unit, calculate the cost of the drivers, proper passive crossover and proper horn and you are approaching $2,000...then add the cost of an 18" woofer, birch ply to build a large box etc. etc. etc. You had better be on top of your game with the costs of the BMS, I'm not worthy so I sit on the sidelines and dream...
Good luck!
you are right Charlie, maybe a mod might want to move the thread...
FAST is related to Fullrange section, while CAST is not. My bad.
FAST is related to Fullrange section, while CAST is not. My bad.
If XO for CAST is circa 400-700Hz it would be called FHAST. As in fullrange horn assisted subwoofer technology. The mods have decided that FAST belongs in Fullrange Forum.
Thanks for the input, yeah the BMS are very expensive which is kind of a turn off... I was just about to completely free myself from exotic driver$ temptations lately. I guess i'm like a junkie who needs an expensive voice coil once in while... 😱
Doesnt Geddes use the B&C DE 250 down to 900hz?
B&C DE250-8 1" Polyimide Horn Driver 8 Ohm 2/3-Bolt
108.5dB sensitivity!! FR 900 ~ 17khz. Possibly 18k.
In theory a 5" driver will be perfectly optimal up to 900hz I think. An 8" will be slightly beaming as ka=2. I'll try to find you some drivers around this range to use in an array to boost sensitivity.
http://www.acousticfrontiers.com/wp-content/uploads/2015/02/driver-beaming.png
B&C DE250-8 1" Polyimide Horn Driver 8 Ohm 2/3-Bolt
108.5dB sensitivity!! FR 900 ~ 17khz. Possibly 18k.
In theory a 5" driver will be perfectly optimal up to 900hz I think. An 8" will be slightly beaming as ka=2. I'll try to find you some drivers around this range to use in an array to boost sensitivity.
http://www.acousticfrontiers.com/wp-content/uploads/2015/02/driver-beaming.png
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Here you go. A super nice SB Acoustics papyrus 5" driver. $23 each, 87dB sensitivity. Nice flat frequency response & 9mm Xmax.
A single 15" driver has an Sd of around 850cm^2. Each 5" driver has an Sd of 87cm^2.
So 5 of these drivers per side..or 10 total.. would cost $230, sensitivity of 96db 1 meter/ 1 watt before baffle step.
A single 15" driver has an Sd of around 850cm^2. Each 5" driver has an Sd of 87cm^2.
So 5 of these drivers per side..or 10 total.. would cost $230, sensitivity of 96db 1 meter/ 1 watt before baffle step.
Just did a comparison between a group of 8x FR151 and a single 950PBbe:
http://www.diyaudio.com/forums/multi-way/300713-living-hi-fi-life-120db-per-hour-3.html#post4918972
Not in the same league at all, both for efficiency and subjective quality.
Sure, the FR151 as a much wider natural bandwith to work with, but there is a trade-off obviously. The Radian CD is limited to a certain bandwith, but excells at that.
...and that is probably the story for all drivers there is. Either you're moderately good at many things... or specialized in only one thing and be great with it.
Ooh, another 'blast from the past'! 😉 Some folks were using Altec 1" compression drivers with just a 3/4" baffle thickness flare and the 1.4" with 1.5" back at least to the early '60s. I've periodically recommended this on HE forums since they're great for HIFI apps.
There's been some high end consumer offerings in recent decades, but don't recall the details or if they're still around.
GM
There's been some high end consumer offerings in recent decades, but don't recall the details or if they're still around.
GM
Somehow I forgot to link to the line array drives lol. Sorry.
https://www.madisoundspeakerstore.c...b-acoustics-sb13pfc25-08-5-paper-cone-woofer/
https://www.madisoundspeakerstore.c...b-acoustics-sb13pfc25-08-5-paper-cone-woofer/