Fostex FE168ez flat spiral horn

[KimBOlesen]

Hi

At last i got my Fostex FE268ez speakers so that i could finish my flat spiral horn's. Size 98cm x 98cm x 15cm




Look at http://www.micro-io.dk

Best regards

Kim Olesen

[MuaDibb]

Hey KimB, Nice job on your speakers. I posted about building some of these but got no replies, not even an opinion on design changes, and you know how cheap opinions are around here.
With that said, are you happy with the sound? The design and plan I have is based on a smaller Fostex, how did you calculate for a different driver? Some of the comments I've seen on this speaker mention a small listening area, have you noticed this? Would you do anything different if you built it again? Lastly, if I built it with a divider in the middle like on the Cornu site, it effectively goes from 4 horns to 8. What would you think of a design that let the back half of the speaker fire normally out the sides, and flipping up the end of the horns on the front so that they fire forward? Also is your site anywhere in English?

Thanks Tom

[KimBOlesen]

Hi

Yes i'm happy with the sound, i still haven't had time to try some other stuffing in the chamber, but have to try to see if it can make changes in the sound, for better or worse.

I used excel spreadsheet "Tractrix_v1.4b.xls" (use google to find it) and calculated the throat size from the speaker parameters. And used the calculator on this website http://melhuish.org/audio/exphypcalc.html to calculate the horn. fs=35hz, horn width is 13cm, lenght is 245cm. I copied the data into another spreadsheet so that i could divide the numbers by 4, and add the walls and make an estimated volume/size of the finished speaker (didn't want it to be bigger than 1m*1m). Extraxted the numbers to Autocad / autocad_to_pdf and printed 4 copies of the horns, think it was 44 A4 papers

Gluing the printout to a large piece of paper and made one snail to control the cutter with. Walls are made of 2mm polycarbonate/lexan, and is glued into the back walls 3mm cut'. In the top the cut is 6mm wide and holds a soft rubber band.. as air seal.

I also thougt about the "forward fire" but how do 35-50hz sound travel? maybe it is better not to make sharp bends that can give you standing waves in the horn. I have also seen the pictures of cornu with an extra wall, he starts of with two horns and split them later into four (correct ?) I tryed measuring the sound travel distance from the foto.... but it didn't make any sense. So i just used a disciption found on his home page (no link.. used google to search the cornu site..)

Best regards

Kim Olesen

[janhifi]

Hi Kim, I'm very curious about the resilts you obtained with the flat spiral horns - I'm looking for a similar spreaker, about 100 x 100 cm to be hung against the wall like a picture. The Cornu people are working on a big flat horn-loaded enclosure, but are not satisfied yet. How far did you come? Thanks, Jan