Re: Re: D9e-I drivers in locally built Feastrex-type enclosure
Although they are expensive, it would be interesting to try those diodes ("power recovery module" is my direct translation from what the maker calls them in Japanese) on other (non-Feastrex) field coil drivers to see how much of an improvement they make in the sound.
Do you notice a difference in the sound according to the switch settings? And what voltage are you feeding the drivers?
-- Chris
BTW said:
Although they are expensive, it would be interesting to try those diodes ("power recovery module" is my direct translation from what the maker calls them in Japanese) on other (non-Feastrex) field coil drivers to see how much of an improvement they make in the sound.
Do you notice a difference in the sound according to the switch settings? And what voltage are you feeding the drivers?
-- Chris
Just a quickie to let you know the "new" things that I know and don't know:
1) The gentleman who built the pine board enclosures I posted about a while back took some measurements with the port open and closed, and he reports that with the port open the D5nf plays flat down to 50Hz and then starts to roll off. With the port closed it plays flat down to 125Hz and then starts to roll off.
2) The 9-inch drivers are henceforth going to have a more compliant damper than previously. In fact, I expect (though I have not confirmed it) that there will be a change in the model name to reflect that.
3) I don't know the T/S parameters for any 9-inch driver made with the new, more compliant dampers. If Feastrex has any on hand they could certainly measure them . . .
4) I expect that in August Pure Music Group (Australia) will start to ship their 2-way speaker based on the Feastrex D5 driver with an active bass unit.
-- Chris
1) The gentleman who built the pine board enclosures I posted about a while back took some measurements with the port open and closed, and he reports that with the port open the D5nf plays flat down to 50Hz and then starts to roll off. With the port closed it plays flat down to 125Hz and then starts to roll off.
2) The 9-inch drivers are henceforth going to have a more compliant damper than previously. In fact, I expect (though I have not confirmed it) that there will be a change in the model name to reflect that.
3) I don't know the T/S parameters for any 9-inch driver made with the new, more compliant dampers. If Feastrex has any on hand they could certainly measure them . . .
4) I expect that in August Pure Music Group (Australia) will start to ship their 2-way speaker based on the Feastrex D5 driver with an active bass unit.
-- Chris
Phil,
Hal Teramoto tells me that he does NOT plan to make a model change on account of these new 9-inch spiders (dampers) that he's using. The reasons for this are as follows.
1) The drivers are visually difficult to distinguish on account of a difference in spiders. The spiders can be visually differentiated in a side-by side comparison, but in the field it would be very hard for anyone to tell which version of the spider his driver had simply by looking at it.
2) Nobody is yet using any of the 9-inch drivers in a commercial loudspeaker manufacturing situation where a change in spiders might throw off their production. So Mr. Teramoto has taken it upon himself to improve the existing 9-inch driver models by changing the spiders.
3) The most noticeable change in the sound was not in the bass, but rather in the midrange and treble. With the new spiders, the drivers seem to be easier to use. In enclosures where drivers made with the previous spiders sounded good, the new type sounds even better. And in some enclosures where the previous type sounded a bit off, the new type no longer sounds off at all. So it seems that drivers made with the new spiders have become more forgiving and give pleasing results more easily.
Mr. Teramoto thinks you could put drivers with the new spiders in an enclosure designed for drivers with the old spiders and get entirely acceptable results. I suspect that is almost certainly the case -- not only "entirely acceptable" but quite possibly more pleasing overall, as that has been the consensus of everyone who has heard drivers with the new spiders. However, at the same time I personally think it is likely that the T/S parameters have changed slightly due to the more compliant spider being used. If you would like to take measurements exactly the way Feastrex would, I can arrange to have the Woofer Tester II sent to you so you can take measurements yourself. Unfortunately Mr. Teramoto shipped off all the units of that model that he could have measured, and if you want to get measurements directly from him, you'll have to wait until he is able to build some more of the drivers and can measure them.
-- Chris
Hal Teramoto tells me that he does NOT plan to make a model change on account of these new 9-inch spiders (dampers) that he's using. The reasons for this are as follows.
1) The drivers are visually difficult to distinguish on account of a difference in spiders. The spiders can be visually differentiated in a side-by side comparison, but in the field it would be very hard for anyone to tell which version of the spider his driver had simply by looking at it.
2) Nobody is yet using any of the 9-inch drivers in a commercial loudspeaker manufacturing situation where a change in spiders might throw off their production. So Mr. Teramoto has taken it upon himself to improve the existing 9-inch driver models by changing the spiders.
3) The most noticeable change in the sound was not in the bass, but rather in the midrange and treble. With the new spiders, the drivers seem to be easier to use. In enclosures where drivers made with the previous spiders sounded good, the new type sounds even better. And in some enclosures where the previous type sounded a bit off, the new type no longer sounds off at all. So it seems that drivers made with the new spiders have become more forgiving and give pleasing results more easily.
Mr. Teramoto thinks you could put drivers with the new spiders in an enclosure designed for drivers with the old spiders and get entirely acceptable results. I suspect that is almost certainly the case -- not only "entirely acceptable" but quite possibly more pleasing overall, as that has been the consensus of everyone who has heard drivers with the new spiders. However, at the same time I personally think it is likely that the T/S parameters have changed slightly due to the more compliant spider being used. If you would like to take measurements exactly the way Feastrex would, I can arrange to have the Woofer Tester II sent to you so you can take measurements yourself. Unfortunately Mr. Teramoto shipped off all the units of that model that he could have measured, and if you want to get measurements directly from him, you'll have to wait until he is able to build some more of the drivers and can measure them.
-- Chris
Hmm..........
http://www.diyaudio.com/forums/showthread.php?postid=1549968#post1549968:
"So on the science part, as one of my first duties at Feastrex, I am to measure all the production drivers for accurate TS parameters using our Woofer Tester Pro.
-Clark"
Just how long does it take to become proficient at getting repeatable results with this machine? He asks (not so) rhetorically.........
I mean at this manufacturer's pricing structure it seems reasonable to me to provide specs with each driver or at least keep them on file for the folks who request them for theirs.
Regardless, a 'weaker' spider = lower Fs, higher Vas all else being equal, so unless it's a lot weaker it would only affect cab design if an absolute minimum size (Vb) is desired.
So how much 'weaker' is it, i.e. what is the percent difference in the spider manufacturer's specs? I can calc the rest.
GM
http://www.diyaudio.com/forums/showthread.php?postid=1549968#post1549968:
"So on the science part, as one of my first duties at Feastrex, I am to measure all the production drivers for accurate TS parameters using our Woofer Tester Pro.
-Clark"
Just how long does it take to become proficient at getting repeatable results with this machine? He asks (not so) rhetorically.........
I mean at this manufacturer's pricing structure it seems reasonable to me to provide specs with each driver or at least keep them on file for the folks who request them for theirs.
Regardless, a 'weaker' spider = lower Fs, higher Vas all else being equal, so unless it's a lot weaker it would only affect cab design if an absolute minimum size (Vb) is desired.
So how much 'weaker' is it, i.e. what is the percent difference in the spider manufacturer's specs? I can calc the rest.
GM
The above is the principal reason my own interest in the Feastrex drivers waned. As a DIY proposition, if they're actually serious about getting more people buying the things, then they are going to have to start getting some average T/S parameters out there.
Like now-ish. PDQ. ASAP. Insert your own phrase here. On current evidence, I can only conclude Feastrex are not particularly interested in increasing their sales to the DIY community. Especially at the very high price bracket they are in. If they had been, from the very start, they would have looked at what the market generally requires, which as a minimum in this case would be some measured parameters. Look at their closest equivalents / rivals -do they provide them?
AER? Check.
Lowther? Check (although you have to ask them when you buy a pair).
PHY? Check.
Fertin? Check.
If Feastrex had done this (hardly a major financial undertaking -indeed, for an effectively brand-new company selling very high-priced drivers, an impartial accountant would not value the minor expense at three skips of a louse & indeed, almost as a given) they would almost certainly have seen greater interest in their units & concomitantly, more sales. People would be able to design their own box, to suit their own requirements, much more easily, and there would also be far more DIY cabinet offerings on the forums.
No, I'm not suggesting that T/S parameters are the be-all & end-all, but they have to understand that the vast majority of enclosures outside of Japan are designed using them to varying degrees nowadays, and that very few people have the facility to measure their own drivers. Simple as that. Besides, when the consumer is spending this amount, it is reasonable to expect the manufacturer to measure each unit for pair-matching anyway. And even if they did measure their own drivers, and posted the results on a forum for general edification, how is anyone to know that they are a reasonably representative sample of all such units? Maybe they would be -one would like to assume so at this kind of level, but ultimately assumptions count for nothing. Facts are what is required.
Imagine, if you will, the following situation: Mercedes launch a new high-end engine for sale to other manufacturers, & inform them that it's 'terrific in all areas, but we can't give you any figures because we haven't taken any. If you buy them & run some tests of course, we'd love to hear from you (and please tell everyone else who's bought one while you're at it).' I would suggest that the analogy to the current situation here isn't terribly far out, and quite bluntly, is equally silly.
Chis, IIRC, made an interesting suggestion some time back too. Something else that might have helped their cause, as a brand-new, small, high-end company, would have been to get two or three sample pairs of drivers out to some respected figures in the DIY community -preferably good designers with no personal involvement. People like Dave Dlugos, GM & Martin King for example could have helped considerably, as people know & respect them greatly, & their experience / experiments / potential design would have inspired others still further & generated additional interest / publicity / call it what you will. Not exactly a cheap exercise initially of course, but again, viewed objectively, I suspect it would have been well worth it, & paid for itself within a very short space of time.
As always of course, YMMV. Just my observations from the fence.
Like now-ish. PDQ. ASAP. Insert your own phrase here. On current evidence, I can only conclude Feastrex are not particularly interested in increasing their sales to the DIY community. Especially at the very high price bracket they are in. If they had been, from the very start, they would have looked at what the market generally requires, which as a minimum in this case would be some measured parameters. Look at their closest equivalents / rivals -do they provide them?
AER? Check.
Lowther? Check (although you have to ask them when you buy a pair).
PHY? Check.
Fertin? Check.
If Feastrex had done this (hardly a major financial undertaking -indeed, for an effectively brand-new company selling very high-priced drivers, an impartial accountant would not value the minor expense at three skips of a louse & indeed, almost as a given) they would almost certainly have seen greater interest in their units & concomitantly, more sales. People would be able to design their own box, to suit their own requirements, much more easily, and there would also be far more DIY cabinet offerings on the forums.
No, I'm not suggesting that T/S parameters are the be-all & end-all, but they have to understand that the vast majority of enclosures outside of Japan are designed using them to varying degrees nowadays, and that very few people have the facility to measure their own drivers. Simple as that. Besides, when the consumer is spending this amount, it is reasonable to expect the manufacturer to measure each unit for pair-matching anyway. And even if they did measure their own drivers, and posted the results on a forum for general edification, how is anyone to know that they are a reasonably representative sample of all such units? Maybe they would be -one would like to assume so at this kind of level, but ultimately assumptions count for nothing. Facts are what is required.
Imagine, if you will, the following situation: Mercedes launch a new high-end engine for sale to other manufacturers, & inform them that it's 'terrific in all areas, but we can't give you any figures because we haven't taken any. If you buy them & run some tests of course, we'd love to hear from you (and please tell everyone else who's bought one while you're at it).' I would suggest that the analogy to the current situation here isn't terribly far out, and quite bluntly, is equally silly.
Chis, IIRC, made an interesting suggestion some time back too. Something else that might have helped their cause, as a brand-new, small, high-end company, would have been to get two or three sample pairs of drivers out to some respected figures in the DIY community -preferably good designers with no personal involvement. People like Dave Dlugos, GM & Martin King for example could have helped considerably, as people know & respect them greatly, & their experience / experiments / potential design
As always of course, YMMV. Just my observations from the fence.
I would have to agree with Scott 100%..
I've been, and still am very interested in the Feastrex drivers.. From reading comments from lots of people that have heard them ,and favor the Feastrex over other very highly regarded drivers, makes me think I have to get a pair and enjoy someday.. Now for me I'd only be able to get the D5nf ,and that would still be a stretch to my thin wallet..
One thing that has bothered me though is the lack of specs. I would think that if I had the expertise to build a loudspeaker driver the caliber of the Feastrex ,then shouldn't measuring them be the easiest part of the whole sha-bang ? Also I would expect at the price level to have very precise specs on the pair I purchase.. Sort of like if Mercedes sells me a car with a 300hp spec engine, then I'd expect 300hp not 260 or etc....
I think a really awesome idea would be to sell each pair of drivers with a birth certificate of how they measured, the same you get with matched vacuum tubes. That way a customer would have the most accurate driver specs and be able to use them in the best way possible, which would really only help to promote the Feastrex name even further IMO... Somebody could be employed to provide each pair of drivers sold, with matched specs and some enclosure suggestions etc.. Dave
I've been, and still am very interested in the Feastrex drivers.. From reading comments from lots of people that have heard them ,and favor the Feastrex over other very highly regarded drivers, makes me think I have to get a pair and enjoy someday.. Now for me I'd only be able to get the D5nf ,and that would still be a stretch to my thin wallet..
One thing that has bothered me though is the lack of specs. I would think that if I had the expertise to build a loudspeaker driver the caliber of the Feastrex ,then shouldn't measuring them be the easiest part of the whole sha-bang ? Also I would expect at the price level to have very precise specs on the pair I purchase.. Sort of like if Mercedes sells me a car with a 300hp spec engine, then I'd expect 300hp not 260 or etc....
I think a really awesome idea would be to sell each pair of drivers with a birth certificate of how they measured, the same you get with matched vacuum tubes. That way a customer would have the most accurate driver specs and be able to use them in the best way possible, which would really only help to promote the Feastrex name even further IMO... Somebody could be employed to provide each pair of drivers sold, with matched specs and some enclosure suggestions etc.. Dave
Scottmoose said:
Please note that I'm currently in no position to do either the requisite testing or auditioning, but 'hope springs eternal', so my current timetable is ~ a year away at the earliest unless a 'whole deck of cards fall' my way to offset the way they've 'fallen' this past decade.........
Regardless, when I was able to afford relatively high end gear (McIntosh, Altec, etc. level) it came with hand written docs of the pertinent final QA station performance test data, though one can always argue whether or not the tests were designed/calibrated to put the best 'spin' on them. Raw drivers OTOH not so much since Qo, T/S measurements design routines were known to only a small group at the time which consisted mostly of manufacturers of which only Altec was forthcoming AFAIK in sharing it with anyone who asked for it.
In today's computer oriented, T/S centric world though, this is totally unacceptable except in the ceiling PA or similar markets IMNSHO, though as always, YMMV. Indeed, at this level I'd want it all like you get from the better prosound manufacturers, impedance, response, impulse, polar, directivity plots along with T/S, but these would have to be a bit generic since they are too time consuming to do, at least at the present time AFAIK, but it's just a matter of time before we'll have the ~equivalent of a WT3 to do it all in the not too distant future without the need to ~replicate Altec's outdoor mid air platform system.
GM
Ummm. Good question. They often have a different approach to we decadent westerners, that's for sure. Depends on what sort of box you mean. Here's one example: http://www.diyaudio.com/forums/showthread.php?postid=1483611#post1483611
A lot is based on SWAG's, a personal philosophy, and some basic facts such as the resonant frequency etc.; some trad. alignments that pre-date the T/S ones too.
A lot is based on SWAG's, a personal philosophy, and some basic facts such as the resonant frequency etc.; some trad. alignments that pre-date the T/S ones too.
"I hear ya"
These recent comments have been duly fed back to the top people at Feastrex.
To make a long story short, they know their own drivers better than anyone else on the planet. They need to understand that they are trying to sell their drivers to people who don't know the drivers nearly as well as they do.
They think there is an over-reliance on T/S parameters and formulaic approaches to enclosure building in the DIY world. Okay, for the sake of argument let's grant that. "So what?" Even if that be granted, they still have a need to sell their drivers into such a marketplace. I have encouraged them to recognize these realities and accommodate them. Especially since they have made public commitments in that direction in the past. (It's not like I've simply been putting words in their mouths.)
Thanks for your patience. And thanks for even couching your criticisms in charitable terms. Feastrex considers itself blessed to have such a wonderful fan base, and I have re-confirmed that to be true. You're all a bunch of great guys.
Anyway, we'll see what happens.
-- Chris
These recent comments have been duly fed back to the top people at Feastrex.
To make a long story short, they know their own drivers better than anyone else on the planet. They need to understand that they are trying to sell their drivers to people who don't know the drivers nearly as well as they do.
They think there is an over-reliance on T/S parameters and formulaic approaches to enclosure building in the DIY world. Okay, for the sake of argument let's grant that. "So what?" Even if that be granted, they still have a need to sell their drivers into such a marketplace. I have encouraged them to recognize these realities and accommodate them. Especially since they have made public commitments in that direction in the past. (It's not like I've simply been putting words in their mouths.)
Thanks for your patience. And thanks for even couching your criticisms in charitable terms. Feastrex considers itself blessed to have such a wonderful fan base, and I have re-confirmed that to be true. You're all a bunch of great guys.
Anyway, we'll see what happens.
-- Chris
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