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-   -   Help with real measurements on the Fostex FE126En and the FE103En fullrange Drivers? (http://www.diyaudio.com/forums/full-range/230157-help-real-measurements-fostex-fe126en-fe103en-fullrange-drivers.html)

cross reference 16th February 2013 02:07 PM

Help with real measurements on the Fostex FE126En and the FE103En fullrange Drivers?
 
Hello all :D.

I have a pair of Fostex Fe 126en drivers and I am getting a pair of Fe130en Drivers next month. Well I am looking for real measurements from these drivers fresh out of the box and when they are broken in. I am looking for graphs on fs,db,wattage and everything else that will help me get the right volume for the box I am going to build for both of these drivers. I know there are plans and other diyers who have done this for us. Well I have already built a proto type box almost a year ago and I want to rebuild this box to the right internal volume for both drivers. So if anyone could give me some help here that would be great. It would save me $800.00 dollars :eek: of having someone else do these drivers for me. Thanks Jd

P.S. I hope I said everything correct :confused:. Jd

xrk971 16th February 2013 02:32 PM

The box dimensions will depend on final T/S parameters which can change after break-in, but I am not sure if it changes that drastically for these Fostex's. When you say measurements and you say dB and Wattage it sounds like freq response measurements with a mic and those don't impact box design like the T/S measurements which are made using something like a woofer tester which just clips to the driver leads and goes to a box connected to computer.

cross reference 16th February 2013 02:49 PM

Yes the final T/S parameters can change after the breakin of the drivers. I don't know if they are that drastically for the fostex drivers at all either? No I am not looking to use a woofer tester or I would have bought one already. I had called and talk to the owner of the org. woofer tester and he told me it is nice to have the woofer tester but, getting the next step up would do me more justice for what I am trying to do. So I hope I answered your questions for you? I am just looking to see if anyone can help me out with these projects I am going to be working on? I just want the right box for the drivers. Jd

Bob Brines 16th February 2013 05:48 PM

It doesn't matter. While the T/S parameters will shift with use, they shift in such a way the the predicted box is the same. Also, if you are dealing with a reliable manufacturer, Fostex and Mark Audio being prominent on the forum, you should use the published data. What you measure may be vastly different from the published data, the difference will be in the method you use to make the measurements. Example: Measuring Fostex drivers with diy low-power current drive produces very different data from the published, but the published data always gives reliable results.

Bob

xrk971 16th February 2013 06:32 PM

Are you asking for box recommendations? If so what kind of application are you looking for? Type of room, type of speaker (BLH, MLTL, TQWT, OB, etc.), type of amp, music you plan to listen to, etc.

cross reference 16th February 2013 06:33 PM

Quote:

Originally Posted by Bob Brines (Post 3372509)
It doesn't matter. While the T/S parameters will shift with use, they shift in such a way the the predicted box is the same. Also, if you are dealing with a reliable manufacturer, Fostex and Mark Audio being prominent on the forum, you should use the published data. What you measure may be vastly different from the published data, the difference will be in the method you use to make the measurements. Example: Measuring Fostex drivers with diy low-power current drive produces very different data from the published, but the published data always gives reliable results.

Bob


Wow Bob very insightful news. I was told this new and not to bring the names up? But ,I have heard that Tang Band, A.N. Drivers, Peerless, vifa and Aurum Cantus is way off. So it just got me thinking? Are the published specs right or wrong? So that is were I was going with that. Again thanks Mr. Bob it helps out alot. JD

cross reference 16th February 2013 06:39 PM

Quote:

Originally Posted by xrk971 (Post 3372559)
Are you asking for box recommendations? If so what kind of application are you looking for? Type of room, type of speaker (BLH, MLTL, TQWT, OB, etc.), type of amp, music you plan to listen to, etc.


Well it depends how far or how deep are you willing to help me out or go the distance with me? we can start with this:

Yes Box recommendations is a must. I am looking to use these speakers as wide range as possible. The room is 10 feet wide by 10 1/2 feet long with 8 foot ceilings. I would like to stay away from the (BLH,OB,SE.) I like P.B., T.L., TQWT,MLTL and my trapazoid box I am working on? Amps are a Dayton dta 100 t-amp for now my other amp is on the fix it bench. Musics is all kinds but, mostly used for t.v. and everyday normal listening dutys. Not loud but, normal. I hope this helps. JD

DrBoar 18th February 2013 06:25 AM

I agree with BB in parts.
How you measure will affect results, both due to driving levels and other facors so here I agree
"While the T/S parameters will shift with use, they shift in such a way the the predicted box is the same" This is true if for example the suspenison is stiffer than intended as this increase Fr and Q while lowering Vas. Also if the compliance over time increase the Fr and Q will drift down to published valueas and Vas increase towards it. However is the magnet way of then Q is simply to high without other factors balancing this out.

In my experience some brands has both high accurity and precision compared to published TS some have one or the other and some few seem to have little QC at all.

planet10 18th February 2013 07:33 AM

1 Attachment(s)
Quote:

Originally Posted by Bob Brines (Post 3372509)
...What you measure may be vastly different from the published data, the difference will be in the method you use to make the measurements...

THis is my approach as well.

T/S parameters are not numbers they are curves.

Break-in affects them -- the Fostex FE typically need many hours of real world use to break-in (100-500 or more).

Drive levels affect them, temperature (both atmospheric & voice coil), humidity, barometric pressure. The orientation and how they are "held" affects them.

There are also significant variation driver to driver in a typical production run. Typical variation i get for instance (usually across 20 drivers measured in the same session) with Fostex are +/- 15-20% depending on the model. This is actually fairly tight. The Mark Audio are atypically tighter at 8-12%.

Factory data is almost invariably measured by LEAP or LMS. I always start with that data when designing a box.

The drivers that people declare having inaccurate T/S are from those guys who measure their drivers & find that their data is different than the factory. It is far more likely that they will be different because the measure environment is measuring at a different place on the curves. If they are close, it is, i believe, more of an indication that the T/S curves are close to horizontal.

Attached is data from the same driver, measured by me, then shipped to Mark Fenlon where he took them to the factory and measured them. Both should be considered valid.

I only use the data i measure to match drivers, ie use it in a relative manner. Drivers being matched always use data from the same session to eliminate weather as a factor.

A corollary to all this, is that one is designing a box, better results are most often obtained when some tolerance to changing parameters is built in. Not a big issue wit sealed boxes (as Bob says, the way parameters usually change does not have a big affect on alignments. Transmission lines, aperiodic boxes also tend to be fairly tolerent. The R added to the vents on my mini-Onkens by the high aspect ratio vents is there for the same reason. Where is really plays a role is in tightly tuned bass reflex boxes. The bass alignment moves out of tune with how high you have the volume and with the dynamics in the music.

dave

xrk971 18th February 2013 08:32 AM

Quote:

Originally Posted by natural sound (Post 3372563)
Well it depends how far or how deep are you willing to help me out or go the distance with me? we can start with this:

Yes Box recommendations is a must. I am looking to use these speakers as wide range as possible. The room is 10 feet wide by 10 1/2 feet long with 8 foot ceilings. I would like to stay away from the (BLH,OB,SE.) I like P.B., T.L., TQWT,MLTL and my trapazoid box I am working on? Amps are a Dayton dta 100 t-amp for now my other amp is on the fix it bench. Musics is all kinds but, mostly used for t.v. and everyday normal listening dutys. Not loud but, normal. I hope this helps. JD

Are you stuck on using the Fe126en? Or are you willing to get other drivers? For wide range use I think you can't go wrong with a MLTL, and they are tolerant of driver variability. A good design for MLTL can be found in the Pensil's or the TABAQ threads, but no one uses the FE126en in a TABAQ (Tang Band). I think you should reconsider the exclusion of the BLH and consider the FH3 or the Cornu wall mount- both are perfect for your smaller space and works with wide range of music. Finally, the TQWT like the Metronome works well with the FE126en. If you are willing to go up to a larger size like the FF165WK, there are a lot more possibilities. I think Bob has a plan for that driver in a MLTL. Lots's of choices...:)
My personal choice would be Cornu (low profile and sounds great for all but hard rock and hip hop) but the FH3 has has positive reviews from many who have tried it with FE126en and is perfect for your room size and wide range of music, and doesn't need to be loud.[


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