Fostex FE103EN transmission line - diyAudio
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Old 16th March 2012, 10:16 PM   #1
Jameslc is offline Jameslc  Australia
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Default Fostex FE103EN transmission line

Hi all i would like to create some transmission for the fostex FE103EN i would like to achieve something similar to these fostex in this you tube video
My Other Listening Room - YouTube

Cheers James
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Old 28th March 2012, 11:33 PM   #2
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What I can tell you for sure is that you can go that low (48-58Hz in the video) with a 4 inch fullranger, because I have experimented enough to be convinced that it can be done, but you will probably need 2 things: a big enclosure, and a good/suitable driver... I don't know how can you know for sure if it will play that low, for example the Fostex in the video (Fe103En) has a Fs of 83 (in reality it's probably higher) which is discouraging but it has been done not just with the design in the video but with the Zigmahornet which is also tuned much lower than Fs.

I have made an estimation of the dimensions of the Hexibase Fostex Fe103En TL and here you are (in cm):
External Height: 90-100 cm
Internal width: 12.3 cm (+- a few mm)
Actual tube cross section: 10 x 12.3 cm (S=123 cm2)
Tube length: 180 - 200 cm
Tuning frequency: 41-47 Hz
Volume (internal): 22-24.5 liters

I've spend some time before arriving at those dimensions and I'm pretty sure they are correct within those limits.
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Old 29th March 2012, 01:44 AM   #3
Jameslc is offline Jameslc  Australia
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Hi Krakatoa thank for calculating those dimensions i really apreaciate it i am very intrested in trying a TL with this sort of response but i'll get on the sketch up tonight and have a bit of a play to see if i can replicate the ones in the videos

cheers james
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Old 29th March 2012, 03:24 PM   #4
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You don't need to thank me for calculating them, you are not the only one around the globe seduced by those towers you see in the video.
By the way, if you have acces to the MJKing's spreadsheets you might want to see how it behaves, from my hornresponse simulation it's ok for the volume but it will lose 2-4 dB in relation to the nominal SPL, however it may not reflect reality, in the sense that the peaks and nulls might be much less severe and the depression in the the 50-90hz region (about 1-2.5 db) might not exist in reality. But that doesn't mean it won't sound ok in reality, BIB's have a very rugger frequency response but they sound good in reality (my ears don't know that for sure, I'm just reproducing other people's words).
Or even better - you can build the real thing from scrap wood to get an idea of how it sounds.

You might want to take a look at this build too - Ok, I lied. Here are a few pics of my “almost” most recent build | MiltonBilt - much larger in volume (don't forget the simple rule of transmission lines and wave guide based enclosures - bigger is better).
And this thread from the pwkdesigns forum - • View topic - My "Other" Listening Room

One last thing I wanted to say (for now) is that I read somewhere that the towers from the video didn't had any stuffing.
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Old 29th March 2012, 03:41 PM   #5
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And another thing - hexibase uses he's own software and formulas which take into account everything, not just the parameters of the driver, also placement in the room and driver placement in box, probably the position of the mouth too ... so in order to reproduce the sound from the setup in the video ... I don't know, you need to be a little lucky, unless you have the means to take into account the room and speaker placement in your design. Just try a simple improvised build of the design (one enclosure) to see if you can get the same sort of sound, and if you can get the song from the video it's even better, I don't know what it is, I would use it my self for testing.
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Old 30th March 2012, 01:31 AM   #6
Jameslc is offline Jameslc  Australia
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yeah ok i thought by the way he calculates it there is something to do with the placement in his room, But by the looks of the room he has got it in my bedroom is the same sort of size i have got more ceiling space but the plan was to build them and see what happen but after reading your post i might just build one of them and see how i go just in case it turns out nothing to what i have expected

cheers james

Last edited by Jameslc; 30th March 2012 at 01:33 AM.
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Old 30th March 2012, 03:56 AM   #7
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Default K's TL for FE103En

Quote:
Originally Posted by krakatoa View Post
What I can tell you for sure is that you can go that low (48-58Hz in the video) with a 4 inch fullranger, because I have experimented enough to be convinced that it can be done, but you will probably need 2 things: a big enclosure, and a good/suitable driver... I don't know how can you know for sure if it will play that low, for example the Fostex in the video (Fe103En) has a Fs of 83 (in reality it's probably higher) which is discouraging but it has been done not just with the design in the video but with the Zigmahornet which is also tuned much lower than Fs...I have made an estimation of the dimensions of the Hexibase Fostex Fe103En TL... :
External Height: 90-100 cm
Internal width: 12.3 cm (+- a few mm)
Actual tube cross section: 10 x 12.3 cm (S=123 cm2)
Tube length: 180 - 200 cm
Tuning frequency: 41-47 Hz
Volume (internal): 22-24.5 liters

I've spend some time before arriving at those dimensions and I'm pretty sure they are correct within those limits.
Hi there K: What is the area of the port? Do you recommend corner deflectors as shown in Supersteve's TL ( deflectors reduce box volume )? ...regards, Michael

Last edited by j.michael droke; 30th March 2012 at 03:57 AM. Reason: added s to deflectors
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Old 30th March 2012, 04:06 AM   #8
brsanko is offline brsanko  United States
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The Fs of the driver by itself is not much of an indicator of how low a TL or horn speaker can go, the biggest limiting factor as far as bass is concerned with this driver is it's very small xmax.
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Old 30th March 2012, 12:19 PM   #9
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Quote:
Originally Posted by j.michael droke View Post
Hi there K: What is the area of the port? Do you recommend corner deflectors as shown in Supersteve's TL ( deflectors reduce box volume )? ...regards, Michael
I forgot to mention that the tube (TL) has a constant section, the "deflector" is probably a means to maintain the S of the tube constant as it corners in the box... so it is 123 cm2, but don't forget I'm just estimating, I don't know for sure.
I have never heard of anything like "deflectors reduce box volume"; the apparent box volume maybe can be enlarged by adding something fluffy on the walls but since it is not a common practice it probably doesn't do much good.
By the way, I don't know how much a deflectors would help but considering that the nearest wall behind the cone is the magnet itself, and it's very close and in this case very large.

To Jameslc: do you own a pair of Fe103en s ? If you already have them you might have tested them in free air, and any enclosure so you can get an idea how low below Fs they can play, in the sense that it is audible but not distorted, and compare it with a driver of similar size that has allot of bass.
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Old 30th March 2012, 12:32 PM   #10
Jameslc is offline Jameslc  Australia
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well i have order the fostex but haven't received them yet, i have made a bit of a mock up of the transmission lines using your dims from up the page and put my corals 4a-70 in it to see how they go but not really the right driver for the TL, i'm going to wait and see what it sounds like with the fostex and go from there but somehow i think the bass in the video is too clean for the xmax of the speaker

Last edited by Jameslc; 30th March 2012 at 12:35 PM.
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