D5nf & NF5ex T/S parameters
I measured the T/S parameters of the D5nf & NF5ex. Please email Feastrex if you need this information, and we will send it to you.
T/S parameters for the D9nf will take about another week, because I must build a test enclosure first.
We made the measurements with the "Woofer Tester Pro" set at the default settings. The engineer who designed our Woofer Tester Pro will soon be examining some Feastrex drivers. Perhaps he will recommend changes to the way we measure the drivers. (As you know, our driver are rather unusual and differ from typical woofers and subwoofers in various ways that might be relevant to the approach to testing.) In that case, we will try to measure the drivers again according to his recommendations, and if the results are different we will announce the new results.
We think these measurements should be basically okay.
Thank you for your patience and kind understanding.
Sincerely,
Hal Teramoto
I measured the T/S parameters of the D5nf & NF5ex. Please email Feastrex if you need this information, and we will send it to you.
T/S parameters for the D9nf will take about another week, because I must build a test enclosure first.
We made the measurements with the "Woofer Tester Pro" set at the default settings. The engineer who designed our Woofer Tester Pro will soon be examining some Feastrex drivers. Perhaps he will recommend changes to the way we measure the drivers. (As you know, our driver are rather unusual and differ from typical woofers and subwoofers in various ways that might be relevant to the approach to testing.) In that case, we will try to measure the drivers again according to his recommendations, and if the results are different we will announce the new results.
We think these measurements should be basically okay.
Thank you for your patience and kind understanding.
Sincerely,
Hal Teramoto
We were testing some speaker-amp interface effects last week. It was amazing how much impedance compensation effected bass reproduction. Do try flattening out the impedance as much as possible after installed on the enclosure.
I also recall someone measured impedance somewhere that showed nominal impedance of close to 20 ohms. Don't know if I remember correctly. Also wonder what the gap height and voice coil height are (or what the Xmax is).
I also recall someone measured impedance somewhere that showed nominal impedance of close to 20 ohms. Don't know if I remember correctly. Also wonder what the gap height and voice coil height are (or what the Xmax is).
Nominal impedance is 16 ohms, and T/S parameter testing shows it to be 14 ohms, which seems to be pretty typical for a nominally 16-ohm speaker. But it will come as no surprise that the impedance actually varies a lot according to frequency -- I remember that from a LONG time ago when there was one early version of the speaker that had undergone testing by some professional testing firm. I'll try to find out about VC and gap height.
-- Chris
P.S. thanks for the Chinese pronunciation lesson for those last two characters . . . I expected it would be something like that.
-- Chris
P.S. thanks for the Chinese pronunciation lesson for those last two characters . . . I expected it would be something like that.
I think Hal Teramoto wants to get confirmation from the tech staff connected with Woofer Tester Pro that his approach to measurement (i.e., using the default settings) is okay before actually putting them online, which can become a more or less non-reversable step. The Woofer Tester Pro tech staff is expected to have a "hands on" session with a pair of Feastrex field coil drivers some time this month . . .
By the way, Clark Blumenstein tells me he will be fixing the lack of contact info on the Feastrex website ASAP.
-- Chris
By the way, Clark Blumenstein tells me he will be fixing the lack of contact info on the Feastrex website ASAP.
-- Chris
I would agree that getting confirmation is a good thing. There have been some initial posts of data earlier, albeit not sanctioned by Feastrex. It just seems an endless exercise however.
As for the website, it has some interesting (background) information but no meaningful information on using any of the drivers. The original (site) did provide some limited specs. The current site only hints that the voice coils are 16 ohms but it's buried in the "Unique materials & artisan technologies" page. Beyond that, zero specs or useful information.
The Lotus Group USA website has PDFs for driver dimensions and the 5e cabinet PDF. This is more useful than anything on the Feastrex site. I guess everyone needs to continue being patient.
Regards, KM
As for the website, it has some interesting (background) information but no meaningful information on using any of the drivers. The original (site) did provide some limited specs. The current site only hints that the voice coils are 16 ohms but it's buried in the "Unique materials & artisan technologies" page. Beyond that, zero specs or useful information.
The Lotus Group USA website has PDFs for driver dimensions and the 5e cabinet PDF. This is more useful than anything on the Feastrex site. I guess everyone needs to continue being patient.
Regards, KM
Patience, Grasshopper...
Hi there, I updated the site, enclosure drawing is up. Hey, even the dimensions are in imperial for all us knuckle headed Americans!
Contact info for Teramoto-san is up now (sorry it was not up before, horrible oversight) so that you can contact him to get -full- driver specs.
-Clark
Hi there, I updated the site, enclosure drawing is up. Hey, even the dimensions are in imperial for all us knuckle headed Americans!
Contact info for Teramoto-san is up now (sorry it was not up before, horrible oversight) so that you can contact him to get -full- driver specs.
-Clark
Re: Patience, Grasshopper...
Hi Clark,
Thanks for updating the website. Hate to get picky on this... but... a few comments. The site is just not logically laid out, i.e., Hal's contact information in under distributors and the cabinet drawing is at the bottom of the products page. Having actual title bars for contact information and technical information would be more proper.
With regard to the drawing, some feedback:
1- The cabinet drawing with thin blue text on a black background is a very poor contrast combination for a CRT. As it's an image, you can't zoom in for better clarity. LCD screens help, but still a tough read.
2- The cutout dimensions for the driver are incorrect. The metric values shown in the original PDF file were 166mm and 135mm. This would convert to 6.53542 and 5.31495 inches. Your drawing shows 6.00 inches and 5.30. I think the actual driver diameter is 165mm, or 6.49605 inches.
3- Material thickness is not implicitly given, but the original PDF was showing 20mm. The drawing is inconsistent here. You can calculate 0.750 in one area, 0.742 in another and 0.760 in another. It doesn't seem like much until you cut the pieces and try to assemble it.
Not sure how the conversions were done, but converting from millimeters to inches is by done multiplying millimeters by 0.03937 (rounded). Overall, I think keeping the original metric values would be better. One can always buy a metric rule... which is what I did. An insignificant cost compared to a pair of D5nf drivers.
Joe Cohen has some PDFs on his site, albeit his 5E cabinet drawing is the older version with the port higher up. Still, he has some driver dimension drawings which are nice. These are partially incomplete as they don't specify the clearance hole (135mm) for the driver. Here's a link to his site:
http://www.lotusgroupusa.com/Feastrex1.htm
I know... you're probably wishing I would go away about now. But when you consider the quality and cost of the materials plus the workmanship that goes into the Feastrex drivers, having limited information which is difficult to find, difficult to read, incorrect measurements and some sketchy parameters just doesn't help the cause. I would like nothing more than to see Feastrex flourish as a company. I love my D5nf drivers, but equivalent attention to detail should be done on documentation as well, not just Hal's extraordinary execution of building each one.
Regards, KM
blumenco said:
Hi Clark,
Thanks for updating the website. Hate to get picky on this... but... a few comments. The site is just not logically laid out, i.e., Hal's contact information in under distributors and the cabinet drawing is at the bottom of the products page. Having actual title bars for contact information and technical information would be more proper.
With regard to the drawing, some feedback:
1- The cabinet drawing with thin blue text on a black background is a very poor contrast combination for a CRT. As it's an image, you can't zoom in for better clarity. LCD screens help, but still a tough read.
2- The cutout dimensions for the driver are incorrect. The metric values shown in the original PDF file were 166mm and 135mm. This would convert to 6.53542 and 5.31495 inches. Your drawing shows 6.00 inches and 5.30. I think the actual driver diameter is 165mm, or 6.49605 inches.
3- Material thickness is not implicitly given, but the original PDF was showing 20mm. The drawing is inconsistent here. You can calculate 0.750 in one area, 0.742 in another and 0.760 in another. It doesn't seem like much until you cut the pieces and try to assemble it.
Not sure how the conversions were done, but converting from millimeters to inches is by done multiplying millimeters by 0.03937 (rounded). Overall, I think keeping the original metric values would be better. One can always buy a metric rule... which is what I did. An insignificant cost compared to a pair of D5nf drivers.
Joe Cohen has some PDFs on his site, albeit his 5E cabinet drawing is the older version with the port higher up. Still, he has some driver dimension drawings which are nice. These are partially incomplete as they don't specify the clearance hole (135mm) for the driver. Here's a link to his site:
http://www.lotusgroupusa.com/Feastrex1.htm
I know... you're probably wishing I would go away about now. But when you consider the quality and cost of the materials plus the workmanship that goes into the Feastrex drivers, having limited information which is difficult to find, difficult to read, incorrect measurements and some sketchy parameters just doesn't help the cause. I would like nothing more than to see Feastrex flourish as a company. I love my D5nf drivers, but equivalent attention to detail should be done on documentation as well, not just Hal's extraordinary execution of building each one.
Regards, KM
Chris,
I'm more than a "well wisher". I want Feastrex to be successful in the long term. My D5nf drivers are keepers and I plan to buy another pair of drivers in the future. Which ones are not completely decided on yet...
You started this thread almost 3 years ago and you and many others have kept it alive and at the top of this forum. The interest is certainly here. I firmly believe that having excellent technical documentation and some proven and recommended enclosures can only help, both now and in the future.
PDF downloads are best, as you can zoom, rotate, print and take it with you. Having the T/S parameters, regardless of how controversial they may be, tends to make the drivers legitimate to an extent from a DIY viewpoint. I think copying the PDF format that Fostex provide with their drivers would be perfectly acceptable.
Regards, KM
I'm more than a "well wisher". I want Feastrex to be successful in the long term. My D5nf drivers are keepers and I plan to buy another pair of drivers in the future. Which ones are not completely decided on yet...
You started this thread almost 3 years ago and you and many others have kept it alive and at the top of this forum. The interest is certainly here. I firmly believe that having excellent technical documentation and some proven and recommended enclosures can only help, both now and in the future.
PDF downloads are best, as you can zoom, rotate, print and take it with you. Having the T/S parameters, regardless of how controversial they may be, tends to make the drivers legitimate to an extent from a DIY viewpoint. I think copying the PDF format that Fostex provide with their drivers would be perfectly acceptable.
Regards, KM
Hi
Hi there,
I will resize a few things to make it more legible. The design is one that Feastrex feels would be best built in solids of your choice (pine, etc.). However, the wood used in every Feastrex original enclosure I saw while in Japan used 16mm marine grade BB ply. In essence, wood choice is left up to the builder, just like in Fostex brochures. Feastrex recommends solids for sonics though. Do be careful with a field coil to use a solid wood which is not prone to shrinkage under heat. Thickness of the particular build cited, looking at the .dwg sounds like 3/4 to me just average what you have there. With solids of course, thickness will vary. With tastes, thicknesses will vary... You must compensate for this with every panel. 5/4 stock? 3/4 stock? What you start with in 3/4 is not actually 3/4 and by the time you plane it down it definitely isn't. I personally deal in either imperial or metric, a simple shortcut is to multiply by 11/28 or 28/11 depending upon the direction you are going. (Ill put a condensed version of this paragraph on the website).
PDFs, new links, those will take much more time than simply leaving things where they currently are and getting them larger enough to see. I made the mistake of getting the drawing large enough to be legible on my monitor (which is pretty nice) and I often forget that things change a bit in the real world of computing.... Ill put Teramoto-san's address at the bottom of each page and also under distributors. Sound good?
BTW, I grew up in Florida... where are you?
-Clark
Hi there,
I will resize a few things to make it more legible. The design is one that Feastrex feels would be best built in solids of your choice (pine, etc.). However, the wood used in every Feastrex original enclosure I saw while in Japan used 16mm marine grade BB ply. In essence, wood choice is left up to the builder, just like in Fostex brochures. Feastrex recommends solids for sonics though. Do be careful with a field coil to use a solid wood which is not prone to shrinkage under heat. Thickness of the particular build cited, looking at the .dwg sounds like 3/4 to me just average what you have there. With solids of course, thickness will vary. With tastes, thicknesses will vary... You must compensate for this with every panel. 5/4 stock? 3/4 stock? What you start with in 3/4 is not actually 3/4 and by the time you plane it down it definitely isn't. I personally deal in either imperial or metric, a simple shortcut is to multiply by 11/28 or 28/11 depending upon the direction you are going. (Ill put a condensed version of this paragraph on the website).
PDFs, new links, those will take much more time than simply leaving things where they currently are and getting them larger enough to see. I made the mistake of getting the drawing large enough to be legible on my monitor (which is pretty nice) and I often forget that things change a bit in the real world of computing.... Ill put Teramoto-san's address at the bottom of each page and also under distributors. Sound good?
BTW, I grew up in Florida... where are you?
-Clark
Thanks Clark,
If I can get my old AutoCAD build running in a virtual machine I might try and get the enclosure done in a DWG file, then convert to PDF. Agreed on everything.... wood thickness varies and you must compensate for it. Inside dimensions are usually best with a recommended material thickness.
I'm currently living in Germany for work but still have the homestead in Florida, Palm Beach County, west Boynton Beach. Where did you grow up in Florida? If you manage a trip back, let me know, be more than happy to have you over for some audio play... good food and wine as well.
Regards, KM
If I can get my old AutoCAD build running in a virtual machine I might try and get the enclosure done in a DWG file, then convert to PDF. Agreed on everything.... wood thickness varies and you must compensate for it. Inside dimensions are usually best with a recommended material thickness.
I'm currently living in Germany for work but still have the homestead in Florida, Palm Beach County, west Boynton Beach. Where did you grow up in Florida? If you manage a trip back, let me know, be more than happy to have you over for some audio play... good food and wine as well.
Regards, KM
Jeremy Clarkson has definitely been stung by one too many jellyfish, and he definitely is cut out to be a Feastrex user:
http://jp.youtube.com/watch?v=WaWoo82zNUA
http://jp.youtube.com/watch?v=WaWoo82zNUA
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