Metal Cone Drivers

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#24
originally posted by 7V
I have in the past posted a recommendation that any DIYer who wishes to buy Bandor drivers should do it quickly. This advice still stands.
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Hi Steve ,

why this?
Is Bandor going out of business soon?
If so, I wonder why ?

BTW: is somebody here who can explain me fundamental constructional differences between the 50mm Bandor and the 50mm Jordan units that exist eventually?

Also I`d be interested to know sonic differences of the first generation 50mm Jordans and the current version. I know that the first generation Jordans did not use a conventional spider but instead as far I know a small metal tube going from the cone back through the magnet and hung up in some sort of felt suspension assembly on the backside of the unit. I`ve once (around 15 years ago) heard one of those and found them really great. I wonder why Jordan have departed from this special kind of suspension in the newer versions. It might just have to do with the very low sensivity this drivers had (something around only 80dB/W if I recall okay) - the newer versions with conventional spiders are far better in this regard but I ask myself if this maybe has degraded sound quality also and that the old drivers were actually better?
Somebody here who compared old and new 50mm Jordans?
 
#25
cocolino said:
Is Bandor going out of business soon?
If so, I wonder why ?
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No Bandor isn't going out of business but Doreen is working closer with Seventh Veil. For the time being Bandor will continue to supply the DIY market and small manufacturers. In the next few months they may cease to supply these markets. This is not yet decided but Doreen may prefer to take things a bit easier and I don't know whether it would be a sound business decision for Seventh Veil to continue as a drive unit manufacturer.
BTW: is somebody here who can explain me fundamental constructional differences between the 50mm Bandor and the 50mm Jordan units that exist eventually?

Also I`d be interested to know sonic differences of the first generation 50mm Jordans and the current version. I know that the first generation Jordans did not use a conventional spider but instead as far I know a small metal tube going from the cone back through the magnet and hung up in some sort of felt suspension assembly on the backside of the unit.
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I believe that your experience is right and that the revolutionary spider had sonic benefits over conventional spiders. However, Ted is not a manufacturing man and I believe that it was too difficult for him to get them produced. There may also be problems with the longevity of this driver.

The Jordan driver has a thinner cone than the current Bandor. My personal view is that it's too thin and has a harshness caused after break-up.

I can't really answer your old v new Jordan drivers but wonder whether the question is academic anyway. Jordan 50mms are harder to obtain than Unicorn eggs.
 
#26
Thanks Steve for Your answers!


I can't really answer your old v new Jordan drivers but wonder whether the question is academic anyway. Jordan 50mms are harder to obtain than Unicorn eggs.
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I agree it may be an academic question in practice but for theoretical thoughts about driver construction it`s interesting though.

OTOH: I saw selling a NOS(!) pair Jordan 50mm`s at ebay recently:

http://cgi.ebay.de/ws/eBayISAPI.dll?ViewItem&category=21997&item=3346998852
 
#27
Re: Re: Re: Something reasonably priced

planet10 said:


In my project with these, i found that a little cone treatment killed the breakup and i was able to run it full-range and just bring in a tweeter at the top.

dave
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Oh yes, I've seen that project. Those look like a great design for a surround speaker too.

I've coated a few drivers here and there. The most notable one was a Focal kevlar which wouldn't stop sounding edgy even with a notch filter taking care of the peak. Some people would gasp at the thought of defacing a Focal, but I was ready to throw them out anyway. After I coated them the peak was gone and the notch was no longer needed, but I also found they lost 2db efficiency, and they no longer had the same amount of detail, presumably due to the coating affecting the transient response. These days I prefer to deal with response curves in the crossover only, mostly to keep the cone light and preserve detail.
 
#28
cocolino said:
OTOH: I saw selling a NOS(!) pair Jordan 50mm`s at ebay
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The Jordan Watts were more like 100mm modules -- too bad the guy doesn't have a picture of the unique basket. They also use the trick suspension.

I bought a pr of these new from Wilmslow in 1975 and put them in a wall mounted TL... they were kinda colored.

I recently saw a set of 4 -- dead, but came along with a full set of factory recone kits.

dave
 
#29
I've been interested in Bandor drivers every sice I listened to Bandor-Bandora monitors (small two way monitors using 50mm wide range and 100mm bass below some 400-600hz).Although these kind of speakers are usually not my cup of tea (I prefer high efficency,currently using old Altec) I found Bandor drivers soundig very,very nice and interesting.I even designed (there isn't much to design) monitors that I'm planning to build.These will use two 50mm ,16ohm modules in parallel and Bandor 150mm bass driver in closed box.These should give more efficency (about90db) and lower bass extension compared to Bandora monitors.i even spoke to Doreen ,almost buying the drivers ,but had some other expences and it didn't work out that time.But I still want to build them.I didn't expirenced any problems ordering drivers from Doreen Bance,but that was a year ago.
Bartek
 
#30
zygibajt said:
I even designed (there isn't much to design) monitors that I'm planning to build.These will use two 50mm ,16ohm modules in parallel and Bandor 150mm bass driver in closed box.These should give more efficency (about90db) and lower bass extension compared to Bandora monitors.
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Hi Bartek

I don't think you'll get 90dB, more like 87dB-88dB.

When you talk about "there isn't much to design", please be a little careful. The Bandor 50mms are superb drivers and need a good enclosure to give of their best. You can put them in an open baffle but don't put them into a straight rectangular box or they'll sound like ... a box. If you look at the Bandoras you'll see they have a sloped front baffle, which is a little better. Incidentally, you can get a much better sound than the Bandoras. They used a wierd double-wound configuration in an enclosure that was undersized.

I'm sure you know this already but don't forget that the 50mms and the 150mms should be sealed from each other.

Also, consider using two 4 ohm units in series rather than two 16 ohms in parallel. The 4 ohms are lighter (less voice coil) and this gives a better high frequency response.

I use the 150mm driver in a 20 litre enclosure for my Little Awesome subs and I don't think there's much that can touch them. Wonderful.

Also, on the subject of coating, I have had good results using C37 on the Bandor full-rangers. I believe that it improves the sound through the cone break-up. You need very little of the stuff (even with three coats) as it won't sink into the aluminium (unlike paper). A little C37 goes a long way with aluminium drivers.
 
#31
Thanks for advices.
I know about separating woofer and wide range 50mm modules.
When it comes to time alingthment I hate sloop front baffles,becouse you are listening to high (high/mid in this case) drivers off axis.I more though about shelved back part of front baffle.There might be some diffractions then ,but I prefer this over slooping the front baffle.
What would you recommend for 50mm modules enclosure?
Which exactly 150 Bandor driver are you using and what is the diffrance between double wound and single wound
Thanks
Bartek
 
#32
zygibajt said:
What would you recommend for 50mm modules enclosure?
Which exactly 150 Bandor driver are you using and what is the diffrance between double wound and single wound
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Yes, you should mount the two 50mms as close together as possible and listen on axis.

If you look at the enclosure design page on the Seventh Veil web site you will see that I have gone to some lengths to ameliorate any diffraction effect and reduce internal standing waves. I use an egg-shape inside.

You may not want to go to as much trouble and expense and so the next best thing may be to ensure that the enclosure walls (internally) are non parallel. As with a room, non parallel walls will not eliminate the standing waves but they should improve things.

I use the 150mm 8 ohm double wound as it only needs a volume of 17 litres. I put them in 20 litre sealed enclosures.
 
#33
Originally posted by planet10
The Jordan Watts were more like 100mm modules -- too bad the guy doesn't have a picture of the unique basket. They also use the trick suspension.
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Dave,
I took a closer look again and now I think You`re indeed right and that this were the 100mm units but the suspension on those were different from the early 50mm units in that they used 3 rods of copper-beryllium-alloy mounted tangentially at the throat of the voice coil former and which act like a spring-suspension.
 
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