FYI: JBL/Edgar Wooden Tractrix going on eBay tomorrow

[HDBRbuilder]

FYI:

A pair of JBL/Edgar 650 Hz Tractrix wooden horns w/drivers are going to close on eBay tomorrow. These are turned from what appears to be solid stacked-block hard rock maple, and are real beauts...a tribute to the wood-turner's art. For what they are, the highest bid so far is only 200 bucks with the reserve not yet met...seems quite low to me. See eBay item # 1348279773.

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[QUiKSR20]

What are those used for?? Subs? with no box just a horn?

Pardon my ignorance if im way off im new to some of this

stuff just trying to learn a thing or 2

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[lynnm]

QUiKSR20

They are designed to be used with either a full range driver,(raw) loudspeaker or a midrange driver. You can do a search on the internet using EdgarHorn for more information.

They serve the same purpose as the various sizes and types of horns that are used in the Klipsch speakers.

[TBrennan]

Quickser---Here's a picture of one of my 550hz Edgar tractrix "saladbowls" using a JBL driver. These are the best sounding horns out there, IMO and also of nearly everyone I've met who's heard saladbowls. Two of us in the Chicago Horn Club, BeanCounter and I, use saladbowls. We both use JBL 2400 series drivers; ****** uses 2420s and I use 2470s with aluminum Radian diaphragms. Mine are made of maple and newer ones are of poplar. I'd pay $600 or so for saladbowls with JBL 1" drivers. New 650hz saladbowls from Edgar are $200 each. They should be crossed at 800hz.

This message has been edited by TBrennan on 05-09-2002 at 05:29 PM

[justin_tx_16]

closed at... US $506.99

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[SOUNDJUNKIE]

Tom, any reason for the material change that you know of? Do you think one sounds better than the other or is it purely manufacturing(turning) ease?

[SOUNDJUNKIE]

If you like horns...take a gander at these! http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1350479067

[TBrennan]

Soundjunkie---Bruce told me he switched to poplar cause it's easier to work. He thinks the poplar sounds a little better, I dunno. I've met several people lately making wooden horns, one young fella in Ohio builds round tractri by building them up from seperate rings that he cuts increasingly large, there's a picture of one of his horns on my site, a black horn with an Altec 288. I've a buddy who builds tractrix horns from foamcore, a plastic coated foam material, they sound very good. Frankly, Bruce sells his saladbowls so cheap building is hardly worth the effort unless one enjoys that sort of thing. And his rectangular tractrix horns are cheaper yet, $150 each for 300hz horns. It was Bruce's articles on tractrix horns in SpeakerBuilder magazine that inspired Ray Delgado at Klipsch to start doing tractrix horns.

This message has been edited by TBrennan on 05-10-2002 at 05:17 PM

[Q-Man]

Where do you go to buy Edgar's stuff?

Q.

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Q-Man

[JLH]

Tom,

Actually, I live in Indianapolis, Indiana. I'm only half an hour from the Klipsch building There is a lot more to proper mid range horn design than just throwing whatever size horn you have, onto whatever driver you have. The reason I bother to make horns is that I am able to match the horns to the driver's parameters and get the best performance. When you throw a 2420 onto a 650Hz tractrix, you are throwing away a good 300Hz on the bottom end. However, if 800Hz is as low you need to go to achivie good system syergey, than theres nothing wrong with it. I on the other hand shoot for maxuim bandwidth for a given driver. We might as well, compression drivers give us tons of effeciency.

John Hasquin (JLH)

[SOUNDJUNKIE]

Damn John, that looks like much fun can be had smoothing out the inside, LOL. How do you go about doing that?

[TBrennan]

John---Good to hear from you. In general I agree that the lower you can push the compression driver the better but my experiences using 1" JBL drivers below 800hz have been discouraging with 1st order crossovers (which I'm currently keen on). On Altec 511B horns JBLs have "clacked" when used 500hz 1st order though they work fine 3rd order. Altec 806 and 902 drivers work fine used 500hz 1st order though. Bruce Edgar and I were discussing this Saturday and his experiences pretty much match mine. The lowest I've crossed my 550hz saldbowls is 700hz. If I had the 350hz bowls I'd try Altec 1" drivers and crossing at 500. However my hornloaded Altec 515Bs sound so fine running up to 700-800hz that I've no itch to cross lower, thus saving me the 900 bucks the 350hz bowls cost. :-) I've been thinking about conical horns lately, they need to be much larger for a given cutoff but they provide an even load in the effected area and a good "launch" and would be easy to build. Whaddaya think?

[TBrennan]

Q-Man---Contact Bruce direct. His phone is 310-630-1621 Email is bedgar@socal.rr.com

[JLH]

SOUNDJUNKIE,

It is actually very easy to turn down horns on a lathe. After everything is put together, it only takes about two hours for the inside, and then about one and a half hours for the outside. What takes the most time is laying out the tractrix curve and cutting out the wood. I do enjoy my work a great deal. I've never really done it for the money, its been more of a research project to find the best sound.

John Hasquin (JLH)

[SOUNDJUNKIE]

John, I can imagine it must be a labor of love and that looks like the perfect tool to perform that labor. What's the largest horn you've ever turned on that lathe? Tom, do you suppose that the JBL's need to have a higher crossover point with the first order designs bc there's too much low freg energy present and the diaphgrams are slapping against the phasing plug or something? Do you get that "clack" with the stock diaphgrams? I also read somewhere that the Altec cabs were designed to use a third order Linkwitz-Reilly crossover, any truth to that? What does Bruce say about it?

This message has been edited by SOUNDJUNKIE on 05-12-2002 at 06:45 PM

[JLH]

SOUNDJUNKIE,

The biggest horn and biggest waste of time was a 220Hz 225Hz horn I built before I had figured out where tractrix horn unloads its compression driver. Making bigger and bigger horns in the attempt to get lower frequency output is foolish and misdirected thinking since your low frequency limit is set by the compression drivers resonance. If you try to use a compression driver below its resonance, you will pretty much just get distortion. Anything above resonance and you are throwing away usable bandwidth. As far as JBL drivers and using first order crossovers at 500Hz, Ive never had a problem. Of course, I like to listen to my music at reasonable levels, 80dB continuous, 105dB peaks. If I know anything about Tom, he likes to listen to music at a more spirited level than I. I am yet to run my 1.5Wrms SE amplifier into clipping. I mean these mid range horns are at 109dB to 112dB 1W@1M, why would anyone need more than 1 good watt? I guess that is just me, I know others may think that too loud is just right.

[SOUNDJUNKIE]

I hear the spirited part. I'm fast approaching it, if not already there myself. That's why the sense of urgency with the questions to Tom. I agree that the marriage between driver and horn must be right. It is much like the interface between electronics. What most do not realize is that it is when the source and load have the same impedance is when the maximum power transfer occurs. There is so much talk about keeping source impedance low and load impedance high that it is nauseating. Were you able to turn the 220Hz horn into something usable with a large format driver or does the change in throat throw all the calculations that far off? Forgive the newbie questions.

[JLH]

SOUNDJUNKIE,

Throat size doesnt throw anything off. A 220Hz tractrix is a 220Hz regardless where you chose to terminate the throat. The only difference is if the horn were made for a 2 compression driver, you would just have to extend the horn back until it reached 1.4 or 1, depending on the driver. You still use the same calculations for the curve; you just plot the coordinates out to 1 or 1.4, instead of just 2. As far as the horn itself was concerned, it served as a footstool for a while, then I used for kindling in the fireplace. If you are going to NY Noise on June 1st, Ill be there. We can talk in person and I can answer all your questions. Dont every be afraid to ask questions, thats how we learn.

John Hasquin (JLH)

[edster00]

JLH,

What amp(s) & tubes are you using?

[TBrennan]

SoundJunkie---Good question, the JBLs I used have Radian diaphragms, those with stock ones I've not tried at 500, 1st order. The clacking is most likely the dia hitting the phase plug. However Altecs, both with stock and Radian dias run 500-1st order no problem. Bruce says 1" JBLs are no good running down to 500-1st order. Altec intended for their 1" drivers to go down to 500, JBL preferred 800 and 1200 and I'm only aware of one instance in which JBL ran 1"ers down to 500 and this was soon changed to 800 (this was on an early studio monitor, the info comes from Don McRitchie over at the Lansing Heritage site). Perhaps Altec had more spacing between the dia and plug, I'm just guessing here. All Altecs I'm aware of used 2nd order-Butterworth crossovers. I never heard of them using anything else.