In dire need of help with my first horn project.
I've settled on a Radian 850PB in an 425hz Azurahorn playing 1k to 10K and with a tweeter above, but I need driver ideas for the 160hz Tractrix horn, to play ±250hz-1k. Budget hopefully < $400/driver. Current production drivers preferred.
I've read of some success with the Radian 950PB used this low (with 4th order XO lets assume), and figure there might(?) be some sense in using fairly tonally matched drivers in the upper bass and midrange horns, but I'm wondering if a 6-10" cone might be a better bet?
On the other hand I like the idea that a cone driver will allow a horn with a shorter axial length which will take up less floor room.
What you guys think vis a vis cones vs CDs at these frequencies? Any brand/model suggestions?
Thanks for any help,
B.D
I've settled on a Radian 850PB in an 425hz Azurahorn playing 1k to 10K and with a tweeter above, but I need driver ideas for the 160hz Tractrix horn, to play ±250hz-1k. Budget hopefully < $400/driver. Current production drivers preferred.
I've read of some success with the Radian 950PB used this low (with 4th order XO lets assume), and figure there might(?) be some sense in using fairly tonally matched drivers in the upper bass and midrange horns, but I'm wondering if a 6-10" cone might be a better bet?
On the other hand I like the idea that a cone driver will allow a horn with a shorter axial length which will take up less floor room.
What you guys think vis a vis cones vs CDs at these frequencies? Any brand/model suggestions?
Thanks for any help,
B.D
A forum member, Angelo, had previously used a 8" Fane Studio midrange for his horn and then switched to a radian 950 PB. He reported a significant increase in detail, dynamics and overall quality.
AV Eikon : finished - Page 2 - Audio Voice Acoustics
The Grande Castine, build around LeCleach horn and with the help of the man behind Musique Concrete, uses the same configuration apparently.
The Cessaro horn as well.
AV Eikon : finished - Page 2 - Audio Voice Acoustics
The Grande Castine, build around LeCleach horn and with the help of the man behind Musique Concrete, uses the same configuration apparently.
The Cessaro horn as well.
Is the compression driver being used below its fundamental resonance? (Look at the impedance curve for the driver mounted in a plane-wave tube.)
Power-handling drops like a stone below resonance, and distortion skyrockets - not to mention the hazard of the diaphragm striking the phase plug. Double-check this before committing to the 250 Hz crossover frequency, which is extremely low for a compression driver.
330 to 400 Hz might be a much safer choice, in terms of driver longevity and keeping distortion down.
Power-handling drops like a stone below resonance, and distortion skyrockets - not to mention the hazard of the diaphragm striking the phase plug. Double-check this before committing to the 250 Hz crossover frequency, which is extremely low for a compression driver.
330 to 400 Hz might be a much safer choice, in terms of driver longevity and keeping distortion down.
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The larger the driver's sd, the greater the "mouth" diameter for loading lower freq.s.
Cones are going to have a larger sd, and as a result will need larger mouths.
Take a look at some of the larger "paging" drivers that are available.. most are pretty cheap, but you can always return product (from a reputable reseller) that doesn't measure well. (..also make sure it doesn't have a voltage transformer.)
Look to partsexpress and MCMelectronics.
Also note that you don't need to fully load the upper freq. response of the driver.. as long as the low-pass is "steep" enough (and low enough) it shouldn't be a problem (..so no super long horns needed).
Scott G, that does not seem correct - I could be wrong. but the principle used is usually that the cone is mounted in a position farther down the expansion length, at a point approximately equal to the diameter of the driver... so the mouth does not change.
Lynn, what you say depends much on the driver in question... it's true for most compression drivers...
EV made some large format compression drivers, I am not sure how large the diaphragm was (not having had one apart) but I saw a pile of them at a local surplus store last year, and the OD of the driver itself was on the order of 10" or so... the exit was probably 2"... At one time Community Light & Sound made this monster low Mid compression driver with an 8" aluminum diaphragm... probably you can find info about it somewhere...
_-_-bear
Lynn, what you say depends much on the driver in question... it's true for most compression drivers...
EV made some large format compression drivers, I am not sure how large the diaphragm was (not having had one apart) but I saw a pile of them at a local surplus store last year, and the OD of the driver itself was on the order of 10" or so... the exit was probably 2"... At one time Community Light & Sound made this monster low Mid compression driver with an 8" aluminum diaphragm... probably you can find info about it somewhere...
_-_-bear
here are a few:
Midrange Driver Threaded 1 3/8 X 18 Thread 40W RMS | DU-40 (DU40) | Distributed By MCM
Atlas Sound PD60A 60W Compression Driver 16 ohms | Parts-Express.com
This is not rated quite as low, but you can "bypass" the transformer:
Dayton D1075T 75W Driver with 70V Transformer | Parts-Express.com
Midrange Driver Threaded 1 3/8 X 18 Thread 40W RMS | DU-40 (DU40) | Distributed By MCM
Atlas Sound PD60A 60W Compression Driver 16 ohms | Parts-Express.com
This is not rated quite as low, but you can "bypass" the transformer:
Dayton D1075T 75W Driver with 70V Transformer | Parts-Express.com
Maybe not what you want.
Selenium D250-X 1" Phenolic Horn Driver 1-3/8"-18 TPI | Parts-Express.com
Selenium D408Ti 2" - 400-2K Selenium D408Ti 2" Titanium Horn Driver 4-Bolt | Parts-Express.com
Let's see what you find to play the ±250hz-1k.
Selenium D250-X 1" Phenolic Horn Driver 1-3/8"-18 TPI | Parts-Express.com
Selenium D408Ti 2" - 400-2K Selenium D408Ti 2" Titanium Horn Driver 4-Bolt | Parts-Express.com
Let's see what you find to play the ±250hz-1k.
Thanks everyone for the ideas, and for the EIGHTEEN SOUND 6ND410 suggestion that was emailed to me.
I'll be investigating them, and the Faital M5N12-80 and P.audio WN-520N that my readings have dug up.
Lynn, I cant find any published impedance curves for the 950pb. Its FR graph shows a gradual lower end roll off without an obvious knee. I found a post by Angelo claiming its resonant freq is 550, and he recons to stay an octave away from it, i.e 1k crossover, but then it appears he later found joy with a 250hz crossover, so although I think 250hz doesnt look good on paper it might be one of those times to trust ones ear instead, or someone elses in this case. Costly compared to the Faital/P.audio if it doesnt work out though...
cheers
B
I'll be investigating them, and the Faital M5N12-80 and P.audio WN-520N that my readings have dug up.
Lynn, I cant find any published impedance curves for the 950pb. Its FR graph shows a gradual lower end roll off without an obvious knee. I found a post by Angelo claiming its resonant freq is 550, and he recons to stay an octave away from it, i.e 1k crossover, but then it appears he later found joy with a 250hz crossover, so although I think 250hz doesnt look good on paper it might be one of those times to trust ones ear instead, or someone elses in this case. Costly compared to the Faital/P.audio if it doesnt work out though...
cheers
B
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..and also of interest:
http://vincent.brient.free.fr/round_horns.htm
I think this one would be better than the Radian for the mid-band (and cost a lot less too):
http://www.critesspeakers.com/D405.pdf
Note that it is NOT the "ti" version.
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I think distortion is complete NO issue for compression drivers, used below Fs.
Audio Asylum Thread Printer
These results are important as well as interesting since the insignificance of Level was not anticipated.
The fact that nonlinear distortion in a compression driver is not a significant subjective parameter is quite
enlightening and useful. Prior to this study, the exact opposite was believed to be true; that nonlinear
distortion was a major problem in compression drivers. Regardless of any previously held notions about
the auditory importance of nonlinear distortion in compression drivers, what the data is saying must be
accepted - nonlinear distortion in a compression driver is simply not a factor to its sound quality.
This conclusion is in agreement with other recent publications on nonlinear distortion in
horn/waveguide compression driver subsystems that conclude that virtually all of the distortion in these
subsystems is the result of the waveguide itself.[2] The data shown here is substantial support for this
position-certainly from a subjective perspective.
One significant result from this study is that there is no reason to consider any aspect of compression
driver design from a nonlinear distortion perspective. In fact, one could argue that these results indicate
that distortion could be substantially increased, in order to save money or tradeoff other aspects of the
design for distortion (like sensitivity), without having a negative impact on the sound quality of the
device. Without access to the results presented in this report, the audio community would certainly have
taken exception to this conclusion, and would likely object most strenuously.
http://www.gedlee.com/downloads/AES_subjective.pdf
there are even 1" compression drivers used to cover down to 300hz.
See the examples with the Sato horns.
links to webpages with pictures and descriptions of Audio Systems with hornspeakers - Page 59 - Audio Voice Acoustics
Jean Michel also confirms positive results :
http://www.diyaudio.com/forums/multi-way/140190-jean-michel-lecleach-horns.html
The best sounding low mid compression drivers I used to listen were:
1) Goto
2) WE555 (I have the Alnico French modification by LMT)
2) Onken
3) Yamaha JA6681 (I have 2 pairs of them)
4) TAD TD2001 (yes, a bit modified and on the Sato horn above 250Hz)
5) Vitavox S2
6) Philips
I have not made any measurements. Bass lowpass i use now 300hz/24db.
The Radian has remained in the lower midrange channel.
I would love to try a GOTO UNIT SG-555P
GOTO UNIT SG-555P????????????16???? - Yahoo!??????
an other interesting alternative is the Vitavox GP1, with a large suspension, similar to the WE555a
Vitavox - Page 2 - Audio Voice Acoustics
that driver should aloud to play quit low in a apropriate horn
Audio Asylum Thread Printer
These results are important as well as interesting since the insignificance of Level was not anticipated.
The fact that nonlinear distortion in a compression driver is not a significant subjective parameter is quite
enlightening and useful. Prior to this study, the exact opposite was believed to be true; that nonlinear
distortion was a major problem in compression drivers. Regardless of any previously held notions about
the auditory importance of nonlinear distortion in compression drivers, what the data is saying must be
accepted - nonlinear distortion in a compression driver is simply not a factor to its sound quality.
This conclusion is in agreement with other recent publications on nonlinear distortion in
horn/waveguide compression driver subsystems that conclude that virtually all of the distortion in these
subsystems is the result of the waveguide itself.[2] The data shown here is substantial support for this
position-certainly from a subjective perspective.
One significant result from this study is that there is no reason to consider any aspect of compression
driver design from a nonlinear distortion perspective. In fact, one could argue that these results indicate
that distortion could be substantially increased, in order to save money or tradeoff other aspects of the
design for distortion (like sensitivity), without having a negative impact on the sound quality of the
device. Without access to the results presented in this report, the audio community would certainly have
taken exception to this conclusion, and would likely object most strenuously.
http://www.gedlee.com/downloads/AES_subjective.pdf
there are even 1" compression drivers used to cover down to 300hz.
See the examples with the Sato horns.
links to webpages with pictures and descriptions of Audio Systems with hornspeakers - Page 59 - Audio Voice Acoustics
Jean Michel also confirms positive results :
http://www.diyaudio.com/forums/multi-way/140190-jean-michel-lecleach-horns.html
The best sounding low mid compression drivers I used to listen were:
1) Goto
2) WE555 (I have the Alnico French modification by LMT)
2) Onken
3) Yamaha JA6681 (I have 2 pairs of them)
4) TAD TD2001 (yes, a bit modified and on the Sato horn above 250Hz)
5) Vitavox S2
6) Philips
I have not made any measurements. Bass lowpass i use now 300hz/24db.
The Radian has remained in the lower midrange channel.
I would love to try a GOTO UNIT SG-555P
GOTO UNIT SG-555P????????????16???? - Yahoo!??????
an other interesting alternative is the Vitavox GP1, with a large suspension, similar to the WE555a
Vitavox - Page 2 - Audio Voice Acoustics
that driver should aloud to play quit low in a apropriate horn
Nice pictures in websites. Bring this Eminence PSD:3006-8 2" Titanium Driver 8 Ohm | Parts-Express.com to the bag.
What about this?:
MONACOR INTERNATIONAL
roduct detail page
I'm using Selenium D405 in dedicated 90x40 Selenium CD horn and the best sound I've got is for 500Hz@24dBLR up. Also tried 360Hz and 400Hz @18dB/24dBLR but were not so good into my system ( http://forum.audiofil.ro/index.php?topic=524.0 ). Hope it helps.
MONACOR INTERNATIONAL
roduct detail pageI'm using Selenium D405 in dedicated 90x40 Selenium CD horn and the best sound I've got is for 500Hz@24dBLR up. Also tried 360Hz and 400Hz @18dB/24dBLR but were not so good into my system ( http://forum.audiofil.ro/index.php?topic=524.0 ). Hope it helps.
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The compression driver I prefer to use to cover this range, is the Community M4. See
http://www.communitypro.com/files/literature/spec sheets/M4_SPEC.pdf.
However, the cost of this unit will bust your driver budget. Other viable candidates operated at slightly higher c/o frequencies [fh] will as well. Alternatively, you can design and build your own phase plug and use a direct radiating low [Qts] driver.
The horn to properly load these drivers is quite large. Horn cut-off [fc] should be approximately octave below the -3db point [fh] of the high pass filter used. Horn length < [fh]/[vs]/4 and mouth perimeter < [fh]/[vs] is contraindicated here. If the horn is of minimum recommended dimensions, then a steep sloped (=> 24/db/oct) high pass filter should be used to protect the driver as it becomes unloaded. Unlike direct radiating drivers, the proximity of the phasing plug imposes displacement limitations on diaphragm movement long before its suspension limits are met.
http://www.communitypro.com/files/literature/spec sheets/M4_SPEC.pdf.
However, the cost of this unit will bust your driver budget. Other viable candidates operated at slightly higher c/o frequencies [fh] will as well. Alternatively, you can design and build your own phase plug and use a direct radiating low [Qts] driver.
The horn to properly load these drivers is quite large. Horn cut-off [fc] should be approximately octave below the -3db point [fh] of the high pass filter used. Horn length < [fh]/[vs]/4 and mouth perimeter < [fh]/[vs] is contraindicated here. If the horn is of minimum recommended dimensions, then a steep sloped (=> 24/db/oct) high pass filter should be used to protect the driver as it becomes unloaded. Unlike direct radiating drivers, the proximity of the phasing plug imposes displacement limitations on diaphragm movement long before its suspension limits are met.
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