I have built mid-range horn according to Bruce Edgar design (speaker builder 1/86) for a 5 inch driver, with one difference: throat in his design was 2 x 2 inches while I made it for the full size of the speaker (4 x 4 inches). Can someone tell what difference does it make, does it have effect on sound and in what way if it does?
I have built mid-range horn according to Bruce Edgar design (speaker builder 1/86) for a 5 inch driver, with one difference: throat in his design was 2 x 2 inches while I made it for the full size of the speaker (4 x 4 inches). Can someone tell what difference does it make, does it have effect on sound and in what way if it does?
If you go back and read the article, Bruce talks about using a larger throat horn for various other drivers, and claimed that the larger throats actually sounded pretty good, if not even better than the small throats.
You can obtain the article any time by going to the Volvotretter website, and look under downloads. It's there in pdf.
I have built mid-range horn according to Bruce Edgar design (speaker builder 1/86) for a 5 inch driver, with one difference: throat in his design was 2 x 2 inches while I made it for the full size of the speaker (4 x 4 inches). Can someone tell what difference does it make, does it have effect on sound and in what way if it does?
Hopefully this thread is not past the expiry date (necromancy).
Did you ever measure the results, and could you post them? and what driver did you use?
I have tried 3 inch drivers but not 4 inch-both domes and wide range.
The Dynaudio D54 2 inch dome as specified by Edgar sounded much better than anything else although a Dynaudio D76 3 inch dome works OK.
The Dynaudio D54 2 inch dome as specified by Edgar sounded much better than anything else although a Dynaudio D76 3 inch dome works OK.
Thanks, I have tried to sim a few different drivers. My observation, so far, is that high Qms drivers tend to sim better. Like the PRV 5mr450ndy has a high sensitivity and Qms=22 seems to sim well. I'd like to see the measurements from the horns and how people deal with the HF roll off. I've also tried a DC28F dome (1-1/8") that worked in a smaller horn.
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I'd like to see some hornresp models - below is my 250Hz Edgar tractrix with 2" x 2" throat and old JBL alnico LE5 with Qts>2 vs University's SAHF on a 511 Altec (that midbass horn came out pretty strong)

@freddi thanks for the graph. The JBL LE5 is one of the drivers Edgar used. It looks like you have a well behaved -10db slope over the midrange 400-4K which is what I see in sims using a similar driver. I added the HornResp input page (pic#1) and unrestricted throat (pic#2) and restricted throat (25cm2, pic#3).
Did you only try the 2x2 throat to get more compression?. Edgar eventually opened the throat to match the driver.
How is the horn sound quality compared to the bare driver ?
Did you only try the 2x2 throat to get more compression?. Edgar eventually opened the throat to match the driver.
How is the horn sound quality compared to the bare driver ?
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- think I quoted the throat size wrong - IIRC, its 2.5" x 2.5" - some drivers look odd such as a near 9K peak with Faital's 4FE32 - might be able to notch that with a coil and cap
the sensitivity for my JBL LE5 doesn't look hot enough to match my midbass horns. (?) I first used the tractrcix/LE5 on top of my K-horns til Bruce came up with the little 100Hz hypex straight midbass horns for 2220H.
what current cone drivers work well on such horns?
the sensitivity for my JBL LE5 doesn't look hot enough to match my midbass horns. (?) I first used the tractrcix/LE5 on top of my K-horns til Bruce came up with the little 100Hz hypex straight midbass horns for 2220H.
what current cone drivers work well on such horns?

HI Gents,
Has anyone found a modern driver that works as well or better then the JBL Le5.
Been thinking about building this horn & would like to keep the open back concept like the original.
Thks
Has anyone found a modern driver that works as well or better then the JBL Le5.
Been thinking about building this horn & would like to keep the open back concept like the original.
Thks
Yes, 5MR450NDY works wonderfully in FL mid horns. Tractrix is great and a friend tried it in Edgar with great results.
PRV 5MR450-NDY for FAST/WAW applications
PRV 5MR450-NDY for FAST/WAW applications
Many thanks XKR may I ask, was the PRV tested on the Edgar Horns build to the exact dimensions as the original that uses the LE5 drivers ?
Thank you again
Cheers
Thank you again
Cheers
There are different size Edgar horns but this one was for a 5in driver, it was a DIY Edgar horn so I can't say it was the exact dimensions. I think the PRV 5MR450NDY will work well on any front loaded horn designed for a 5in driver.
Many thanks again XRK. I have 2 plans of the Edgar horns 1 original for JBL 5 inch driver & the other is for the Dynaudio Dome mids. Will give it a try.
Cheers
Cheers
- didn't get the 5" PRV yet - my old 250Hz tractrix built by Bruce has a 2.5"x2.5" square throat and behaved very well with alnico LE5A
here's what it did with 4fe32 and a 3fe22 variant with large dust cap (too rough to use FR direct radiator)
here's what it did with 4fe32 and a 3fe22 variant with large dust cap (too rough to use FR direct radiator)

Hi Freddl,
Thank you again. Seems like the 3fe22 looks smoother. Original horns drawing for the Le5 was a 2x2 inch hole, wonder if Mr Edgar found better performance by enlarging it to 2.5x2.5 inch
Many thanks
Thank you again. Seems like the 3fe22 looks smoother. Original horns drawing for the Le5 was a 2x2 inch hole, wonder if Mr Edgar found better performance by enlarging it to 2.5x2.5 inch
Many thanks
Guys, is such a horn design good for midranges frequencies ? I believed it was better for 100 hz to 400/800 hz ? Why not a "normal" horn if 700 hz to mid-trebles is mandatory ?
Sumotan what do you want to acheive and for what purpose, subjective targett please ?
Sumotan what do you want to acheive and for what purpose, subjective targett please ?
For mids, the Faital 3FE22 is excellent as is ScanSpeak 10F/8424. I have even had good success with a TC9FD. Because the horn loading is so good, you only have like 40micro meters of cone movement for about 100dB output. The distortion associated with such small movements is very low. The gain is typically 10dB so an 85dB driver becomes 95dB. The 95dB 5MR450NDY becomes a 105dB driver. You have to really be careful to wear hearing protection when testing these horns under any appreciable voltages. They sound so clean and distortion free that your hearing is not able to perceive “loudness” as that is tied to perception of distortion. So after a few sweeps at 2.83v, my ears were ringing.
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