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What is the correct orientation of a EV T-35 type horn, should the narrow horn mouth dimension be positioned horizontally or vertically?
What are the factors involved? I've seen the horns positioned in both orientations.
Do similar considerations apply to, say, a vintage University HF-206 tweeter horn ??
Thanks in advance for any and all information and help.
Jeff Medwin
Follow Ups:
About a later version of the Jensen RP-302 which has a rectangular horn. Bill Fitzmaurice provided some good info (use the link below). I have been using them vertically ever since and they sound great.
Gerry
What a great group of people on this Forum !!
Jeff Medwin
An un-obvious aspect of horns is that when you make them have an asymmetric coverage angle where one plane is considerably different than the other is “pattern flip”.
When you go down in frequency to where one plane has lost pattern control (found by Don Keele’s “pattern control loss frequency” formula), the wide direction becomes narrow and the narrow the wide plane. The radiation is then the opposite of what the horn looks like.
For a horn that small and so asymmetric, the pattern loss frequency is very high and so to get wide dispersion horizontally, it is usually better to mount that horn vertically as most of it’s operating range is below the pattern flip range.
In general, so far as the radiation angles, its a good idea to avoid very asymmetric horn flares as what you get is not what one would think based on the looks of it. You can make a horn without pattern flip but it is not a simple shape or has to have nearly equal vertical and horizontal wall angles.
Best,
Tom Danley
Danley Sound Labs
I made a home brew full horn system about 30+ years ago and ended up using the T35 vertical, sitting on the top of the mid enclosure and without a baffle. 12dB/oct @ 5K. The speakers were corner horns so horizonal dispersion was not important. Later I went with T-350's (same x/o) Horizonal with a baffle. Experimentation over time, each of those situations with each tweeter yielded the most pleasing results. YMMV..
To sum it up, t35 unbaffled, vertical (with magnet stand to prop up the rear) was the best for my app.
Jeff
This will depend a great deal on what you are going to mate with the T35 for the midrange. Typically this would have been an EV 8HD midrange horn with an 1823/1824 comp. driver with a 3500 Hz crossover. EV indeed pictured them both mounted with the long dimension vertical on the flat baffle of their box plans using a direct radiator woofer. However there's always the factor of what fits: on the spec sheet for the EV 848HF coax mid horn, the small forward firing upper mid horn is seen in the pic with a vertical mount, but in the drawing is seen in the horizontal. The related 848A is shown only with the small mid horn in the horizontal position relative to the larger horn loading the rear of the diaphragm. If you"re mounting the T35 "open air", you can try it both vertical and horizontal and see how it integrates with what's below (you'll have to rig up a mounting "sled" to get the T35 to stand up in the vertical position of course). If you go this way, you have the option of getting the T35 and the mid in phase (aka Time Aligned^tm), but if you're going with a flat baffle mount, where the mid horn and T35 mouths will end on the baffle, then this will not be possible without delay in the crossover or digital domain. The crossover point you will choose is another factor, but don't expect much output from the typical T35 over around 7K Hz. or so, and the 3500 Hz lower crossover point was chosen by EV to avoid a resonance in the octave below this. There were several T35 variants: early ones had alnico magnets and were 16 Ohms; later ones were 8 Ohms with alnico, but square ceramic magnets appeared at some point with the T35A; the T35B had a smaller magnet both in alnico and ceramic versions, and about 3 dB less output. The University HF tweeters I have seen had the smaller magnets similar to the T35B. Drivers and crossovers which were superseded by later models in the EV line frequently got a grey paint job and the University badge.
Hope this helps (but it all may be more than you wanted to know ; )
Paul
As drlowmu might say, try it both ways and report back to us ;) Ah, just wising-off...
To save djk from having to repeat himself, here are some of the considerations (dive about 2/3 down the page to his post):
http://forums.klipsch.com/forums/p/4322/29599.aspx
If you look at vintage EV literature for the EV Patrician and Georgian, the tweeter is shown in the vertical position. The kit for the Aristocrat cabinet has the tweeter in a vertical position. The old catalog listings for the TRX speaker and the T35B also show the tweeter vertical. The tweeter "looks" better in the horizontal position. The "looks" aspect seems to have won out over sound over the years.
hey Jeff: the T-35 is a diffraction horn lens and was designed to be mounted with the long axis vertical. I cannot comment on the other horn. I can say that the T35 lens is remarkably similar to the tweeter used in the Heresy 3 and Cornwall 3. Best regards Moray James.
moray james
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