Hey there.
I have been interested in 2" compression drivers that would not make me sell my car (so no TAD, no Ale, no Goto, ...).
I have two favourites :
BMS 4592ND
Beyma 850ND
Do you guys have any feedback on these drivers ? What is basically
The BMS is coaxial and does not need a tweeter, I have Fostex T90A which still could be used, but a passive crossover would not be easy because the efficiency is quite difference ?
I would like to build a tractrix or JMLC squared horn to go with.
Thanks, Greg.
I have been interested in 2" compression drivers that would not make me sell my car (so no TAD, no Ale, no Goto, ...).
I have two favourites :
BMS 4592ND
Beyma 850ND
Do you guys have any feedback on these drivers ? What is basically
The BMS is coaxial and does not need a tweeter, I have Fostex T90A which still could be used, but a passive crossover would not be easy because the efficiency is quite difference ?
I would like to build a tractrix or JMLC squared horn to go with.
Thanks, Greg.
I'd avoid titanium drivers generally ("bright") - that removes quite a few possibilites.
Bert over at BD-Designs has been working with the BMS coaxial for sometime now - specifically on the crossover but also with some modest physical changes. (..and no, he does not provide information on either.) Obviously he likes them enough to use them.
Another possibility is from Radian:
http://www.radianaudio.com/products/compression/2neo_driver.php?viewT=compression&viewC=2neo_driver
but they also have some lower priced drivers that are also reputedly excellent:
http://www.radianaudio.com/products/compression/2_driver.php?viewT=compression&viewC=2_driver&viewI=
(this co. actually makes replecement diaphrams for TAD - yes aluminum replacing Be, and several on the HiEff. board of the Asylum have preferred the radian replacements).
Note though that even with a very well done horn, a larger format driver will suffer from "beaming" to a greater extent than a smaller (or a co-axial) driver.
You might also consider a commercial horn or waveguide. (DDS Horns generally, or Bert's for the BMS co-axial.)
Bert over at BD-Designs has been working with the BMS coaxial for sometime now - specifically on the crossover but also with some modest physical changes. (..and no, he does not provide information on either.) Obviously he likes them enough to use them.
Another possibility is from Radian:
http://www.radianaudio.com/products/compression/2neo_driver.php?viewT=compression&viewC=2neo_driver
but they also have some lower priced drivers that are also reputedly excellent:
http://www.radianaudio.com/products/compression/2_driver.php?viewT=compression&viewC=2_driver&viewI=
(this co. actually makes replecement diaphrams for TAD - yes aluminum replacing Be, and several on the HiEff. board of the Asylum have preferred the radian replacements).
Note though that even with a very well done horn, a larger format driver will suffer from "beaming" to a greater extent than a smaller (or a co-axial) driver.
You might also consider a commercial horn or waveguide. (DDS Horns generally, or Bert's for the BMS co-axial.)
Thanks for the replies.
So ok, the Beyma has a titanium diaphragm wheareas the BMS has a polyester one. The radian 950 PB does not seem to have a flat response or it's because of the horn they used. The 850PB has a much flatter response.
I am not against buying a horn if the price is fair (no $1000 wooden horn). I'll check the ones you talked about.
So for the BMS the problem would be to do the crossover as it it quite hard to get information about it.
Greg.
So ok, the Beyma has a titanium diaphragm wheareas the BMS has a polyester one. The radian 950 PB does not seem to have a flat response or it's because of the horn they used. The 850PB has a much flatter response.
I am not against buying a horn if the price is fair (no $1000 wooden horn). I'll check the ones you talked about.
So for the BMS the problem would be to do the crossover as it it quite hard to get information about it.
Greg.
Another thing :
I currently own Fostex FE208Ez in a front tractrix horn with a T90A in the center and JBL 2226H running from 40 to 300hz.
I really like the tweeter a lot. I guess a compression will be better in the mids, more energy and so on but what about in the upper frequencies ?
But at first I could use the BMS full range and then try some tweeters with active filtering.
I currently own Fostex FE208Ez in a front tractrix horn with a T90A in the center and JBL 2226H running from 40 to 300hz.
I really like the tweeter a lot. I guess a compression will be better in the mids, more energy and so on but what about in the upper frequencies ?
But at first I could use the BMS full range and then try some tweeters with active filtering.
The response for all the drivers is highly dependent on the horn its coupled to (in effect - its not something I'd be particularly worried about).
A good passive crossover can be tricky - the easiest thing to do is go active with the Behringer digital crossover and some extra amplification.
This is the horn I'd recomend:
http://www.ddshorns.com/catalog.php?page=CFD2110Pro
The horizontal dispersion pattern is broad and this helps with reproducing realistic imaging and soundstage artifacts endemic to the recording. Looking at the dispersion pattern you'll notice 4 plots (lines) that don't match up with the others. The most deviated 2 plots (the 2 inner circle lines) represent the top octave response at 1/3rd an octave (decreasing) from 16 kHz. (i.e. the inner most represents 16 kHz and the secondary inner most line represents 1/3rd an octave below this - 13.333 kHz.) The other 2 less deviated lines represent from 630 Hz up - ONLY if you are crossing below 800 Hz should you concern yourself with these two lines and matching dispersion with your mid driver - the lower the slope the less you need to worry (with respect to matching dispersion). Note that you don't have to purchase two of these - you could always purchase 1 and then use that as a mould for two cement horns.. AND you could even add JMLC's radius edge flair to improve diffraction.
In your situation I'd prob. purchase the Radian.. and try-out a passive 1st order filter for the super-tweeter anywhere between 12 kHz and 22 kHz. (..and the pasive parts value will be cheap because the cap (if parallel) will be small.)
Consider some cheap transformer attenuators (transformer volume control 8 ohm 10+ watts) to lower the eff. of the drivers to match the rest of your drivers. Despite the effects of core hystersis, it works a LOT better than using resistance for padding down more than 3 db. (..most are stereo - just use one "leg" of the stereo volume control for the driver.)
A good passive crossover can be tricky - the easiest thing to do is go active with the Behringer digital crossover and some extra amplification.
This is the horn I'd recomend:
http://www.ddshorns.com/catalog.php?page=CFD2110Pro
The horizontal dispersion pattern is broad and this helps with reproducing realistic imaging and soundstage artifacts endemic to the recording. Looking at the dispersion pattern you'll notice 4 plots (lines) that don't match up with the others. The most deviated 2 plots (the 2 inner circle lines) represent the top octave response at 1/3rd an octave (decreasing) from 16 kHz. (i.e. the inner most represents 16 kHz and the secondary inner most line represents 1/3rd an octave below this - 13.333 kHz.) The other 2 less deviated lines represent from 630 Hz up - ONLY if you are crossing below 800 Hz should you concern yourself with these two lines and matching dispersion with your mid driver - the lower the slope the less you need to worry (with respect to matching dispersion). Note that you don't have to purchase two of these - you could always purchase 1 and then use that as a mould for two cement horns.. AND you could even add JMLC's radius edge flair to improve diffraction.
In your situation I'd prob. purchase the Radian.. and try-out a passive 1st order filter for the super-tweeter anywhere between 12 kHz and 22 kHz. (..and the pasive parts value will be cheap because the cap (if parallel) will be small.)
Consider some cheap transformer attenuators (transformer volume control 8 ohm 10+ watts) to lower the eff. of the drivers to match the rest of your drivers. Despite the effects of core hystersis, it works a LOT better than using resistance for padding down more than 3 db. (..most are stereo - just use one "leg" of the stereo volume control for the driver.)
Hi,
You've got some good choices there. The BMS drivers are well liked by many on the web. I've never heard them, but they sure get rave reviews.
Don't forget about used drivers. You can often find used JBL or Altec horns and drivers at good prices. I'm very happy with my Altec 811 horns and 806 drivers. You may be able to find them or something like them for less than the cost of the new stuff. And if you don't like them, they are easy to resell.
BTW, I used to live in Toulouse - not too far from the airport. On the north side of town in the section called "les Minimes". A very long time ago. Cool town, Toulouse!
You've got some good choices there. The BMS drivers are well liked by many on the web. I've never heard them, but they sure get rave reviews.
Don't forget about used drivers. You can often find used JBL or Altec horns and drivers at good prices. I'm very happy with my Altec 811 horns and 806 drivers. You may be able to find them or something like them for less than the cost of the new stuff. And if you don't like them, they are easy to resell.
BTW, I used to live in Toulouse - not too far from the airport. On the north side of town in the section called "les Minimes". A very long time ago. Cool town, Toulouse!
panomaniac said:
Hi,
Yes I got good feedbacks on the BMS 4592ND and the price is fair. The Beyma has some good feedbacks too you must add a tweeter and Scott said that a Titanium diaphragm is not so good.
So there is also the Radian but I must say that I find the measurements from their documentation quite weird...
I don't know about used drivers, I would be affraid of getting a damaged one. 4-500$ for a good new 2" driver seems fair to me.
Yeah Toulouse is a cool city, I prefer living here than in Paris. I live in "Rangueuil". Donc tu parles français ?
Merci.
ScottG said:
I must say that I am quite seduced by the BMS because it can work without a tweeter and the frequency response published by Radian is not very sexy. The 850PB seems to be much flater.
I got Fostex L-Pad attenuators, I don't know if you think they would be OK. I thought it was just an adjustable resistance...
I'm gonna check stereo attenuators on google.
Thanks again, Greg.
Hi ,
Sorry I'm late . What's wrong with Tad ? I got my TD4001 second hand for £450 the pair . You can pick up units with blown diaphragms much cheaper and reload with Radian replacements for around the same cost . Probably a lot cheaper than the BMS co-ax I seem to remember the UK distributor Adam Hall was quite literally asking an arm and a leg for the BMS
cheers
316A
Sorry I'm late . What's wrong with Tad ? I got my TD4001 second hand for £450 the pair . You can pick up units with blown diaphragms much cheaper and reload with Radian replacements for around the same cost . Probably a lot cheaper than the BMS co-ax
I seem to remember the UK distributor Adam Hall was quite literally asking an arm and a leg for the BMS cheers
316A
panomaniac said:
Yes. However, I believe the X-tealth are a bit less expensive.
The 1500 (1.4) and 2000 (2") are both excellent for the money.
Same driver other than the extended throat for 2" flares.
After listening to electostatics at home for the past twenty+ yrs, this one one of the few pro HF drivers I could stand. Very smooth, extended.
Used drivers can be quite good - especially for specialized use. (..consider that true midrange compression driver from all but BMS are quite expensive today.)
The problem with purchasing used however is magnet field strength (beyond replacing a diaphram). Magnet Flux can and often does decrease over time. This can alter the freq. response and in particular makes pair matching *difficult*. Prob. not something for a novice to get into. Additionally, there is NO advantage to a lower cost TAD driver than the Be diaphram (..and some have mentioned the diaphram isn't neccesarily an advantage either).
This loss in field strength over time is a significant factor for preferring neo motors over all others (..excepting field coils of course). The magnetic hysterisis is another factor for recommending them (similarly to Alinco).
If you like the BMS co-axial - then by all means get it. Just remember though that you may need some measurment capability to get the best from the driver with regard to crossovers. (..and of course the Behringer has this automated.)
btw, I don't know what the pricing in Europe is.. but in the US its this:
http://www.assistanceaudio.com/02_bms.html#pricing
The problem with purchasing used however is magnet field strength (beyond replacing a diaphram). Magnet Flux can and often does decrease over time. This can alter the freq. response and in particular makes pair matching *difficult*. Prob. not something for a novice to get into. Additionally, there is NO advantage to a lower cost TAD driver than the Be diaphram (..and some have mentioned the diaphram isn't neccesarily an advantage either).
This loss in field strength over time is a significant factor for preferring neo motors over all others (..excepting field coils of course). The magnetic hysterisis is another factor for recommending them (similarly to Alinco).
If you like the BMS co-axial - then by all means get it. Just remember though that you may need some measurment capability to get the best from the driver with regard to crossovers. (..and of course the Behringer has this automated.)
btw, I don't know what the pricing in Europe is.. but in the US its this:
http://www.assistanceaudio.com/02_bms.html#pricing
ScottG said:
Hey Scott,
you explained why I am not to much into buying used speakers, you can also add that PA components are often used roughly and you don't know how the previous owner took care of them...
I own Fostex T90A tweeters : http://www.madisound.com/pdf/fostexdrivers/t90arev.pdf
They are 106db/w efficient, so I think I would have to use an attenuator for the compressions.
http://www.madisound.com/cgi-bin/index.cgi?cart_id=%%CArt_id%%&pid=316
I think a first order crossover would be ok at about 7-8 Khz, what do you think ?
But yeah I would need to do some measurements.
I am doing digital filtering with my soundcard. If I want to add a way I will have to upgrade the soundcard. I will do it but not right now, so at first the tweeter will be passive. I also think that there is much more improvement in doing active filtering with loud frequencies. If I get the coax BMS I might also use their "tweeter".
Btw, which PA tweeter ? JBL 2405h ? 2402H ?
Greg.
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