unaHm, I worked out the curve old-school, with a straight edge, a protractor, and a little bit of trig. For a rectangular horn it is pretty straight-forward. Lay out the sides the way you would for a straight horn, but with a series of angled sections to make the curve. Then shorten and lengthen the top and bottom to fit.
Your cardboard horn is pretty similar to the first horn I built. Straight on axis, the frequency response should be close to the raw response of the driver.
Your cardboard horn is pretty similar to the first horn I built. Straight on axis, the frequency response should be close to the raw response of the driver.
Ah, that's good to know! I was probably over-complicating what I thought needed to be done.
Yes, a square horn is definitely the way I'll go this time. I just want to be sure that I understand, so in the curved section, for each segment you effectively subtracted from the side that forms the inside of the curve, and add to the 'outside'?
I understand that it'll be a wedge shape, but did you keep the centre of each panel a uniform width? For example, if you had 10cm segments, did you keep the width at the centre of the panel 10cm, and then have the inside and outside ends effectively 'pivot' on that centre width?
Sorry, my description isn't that great!
Yes, a square horn is definitely the way I'll go this time. I just want to be sure that I understand, so in the curved section, for each segment you effectively subtracted from the side that forms the inside of the curve, and add to the 'outside'?
I understand that it'll be a wedge shape, but did you keep the centre of each panel a uniform width? For example, if you had 10cm segments, did you keep the width at the centre of the panel 10cm, and then have the inside and outside ends effectively 'pivot' on that centre width?
Sorry, my description isn't that great!
unaHm,
While you are taking cardboard folding and taping to a new level 🙂 any thoughts on the horn above this midbass horn? And more specifically it's flare? Another tractrix? Maybe time, to give some thought about how to fix this other upper horn to the midbass.
While you are taking cardboard folding and taping to a new level 🙂 any thoughts on the horn above this midbass horn? And more specifically it's flare? Another tractrix? Maybe time, to give some thought about how to fix this other upper horn to the midbass.
That's a good point 🙂 Deciding where the bend should go needs to be decided, based on the high frequency horn. The one I have is this:
Midrange / Tweeter Horn ABS Screw Thread 6 X 6 Inch | NTX-1425 (NTX1425) | Distributed By MCM
Specifications:
- Throat diameter: 1 3/8"
- Outside frame: 6" x 6"
- Mounting depth: 9.625"
- Total depth: 9.75"
- Mounting hole diameter: 5.5"
- Screw holes: 0.2" on a 6.125" diameter
- Lug with a 0.2" through-hole for swivel or PA mounting
I hadn't really considered making my own, but it's possible! It would probably need to have a low roll-off of 1kHz, and if I used a Tractrix or Le Cleac'h horn it could possibly be shorter.
The compression drivers I have (Pyle PDS521) are screw-in, so I'd have to think of how to mount it properly.
Yes, for the most part. I tried to maintain a uniformly shaped cross section perpendicular to the center-line of the horn.
You have it sideways, "Patrick Bateman" in his "Square Pegs" thread around post #614 concluded that narrow horns had worse frequency response due to his experience of listening to badly designed thin diffraction horns designed for under dash auto use, and his attempts of cutting holes in the throat of narrow Le Cleach type horns, all of which had terrible frequency response.
He latter realized this conclusion was incorrect.
I'll repeat what I wrote then, that smooth frequency response is not based on horn dispersion.
Regarding bending the horn, there will always be some path length differences in the reflected waves, when the differences are a more than around 1/4 wavelength ragged frequency response will result, and polar response is compromised.
Regarding building HF horns, they are no more difficult to build than LF or MF horns, but because the wavelengths are so much shorter, attention to detail must also be much greater.
Regarding building a short Le Cleach HF horn to go above your mid horn, they will not match in dispersion around 1000 Hz, the (straight) mid horn will be more narrow.
Thread on to flat plate adapters are fairly cheap, or you can make them yourself by drilling a hole just slightly smaller than the thread diameter in a piece of plywood and screwing the driver in.
Art
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This is correct. I think the issues that I had were mostly due to crappy construction. I've basically given up on making my own midrange and high frequency horns, because it requires a level of craftsmanship that I just don't have. My current speakers use Pyle horns that I bought from PE. Fit and finish makes a huge difference at midrange and high frequencies.
unaHm,
An Autotech tractrix would be stretching the budget? The MCM horn seems to be exponential and quite directional. Maybe someone can help out with a good alternative. (far below the Autotech 😉 price range)
AutoTech Tractrix-1000 - Horns DIY Sound Group
Or a diy paperhorn 🙂
http://www.inlowsound.com/
An Autotech tractrix would be stretching the budget? The MCM horn seems to be exponential and quite directional. Maybe someone can help out with a good alternative. (far below the Autotech 😉 price range)
AutoTech Tractrix-1000 - Horns DIY Sound Group
Or a diy paperhorn 🙂
http://www.inlowsound.com/
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Faital pro makes a nice little elliptical tractrix horn - they are inexpensive and sound great - load nicely for treble
Faital Pro Bolt On Horn Lens 80 Deg X 70 Deg | STH100 | Faital Pro
Faital Pro Bolt On Horn Lens 80 Deg X 70 Deg | STH100 | Faital Pro
With my TAD 2001 they go to around 1.4K - with the Celestion 1425 around 2.5k with Community SS1801 around 1.4K - with Emilar 175 around 2K - I like them best for treble with the Celestion crossed at 3.5k. I never really listen to them except as treble because I have so many mid horns
don't know if it could be called a midbass horn, but have been thinking about doing a midhorn from 500 to 1500hz with 6"
would that work ?
don't know about that 'flipping' polar stuff 😀
ehh, when polar response 'flips' around, what listening distance would we be talking about ?
would that work ?
don't know about that 'flipping' polar stuff 😀
ehh, when polar response 'flips' around, what listening distance would we be talking about ?
This will work, it's more of the "wave guide" then a horn but the price is right
JBL 6.5 Inch WaveGuide
JBL 6.5 Inch WaveGuide
Some very interesting ideas! An MTM as a horn is pretty interesting too, and seems like a 'poor man's synergy' 🙂 Of course, I'm just saying that for humour...I've heard neither design in person!
Art and Patrick - my apologies for misreading the thread. I think that there was so much data flying around that I warped myself into confusion 🙂
I think my caution with building my own HF horns is pretty much as Patrick has stated himself - I don't know if I'd have the tools or craftsmanship to be accurate enough. I could certainly try, especially if it's down to full or half millimetre measurements.
I'm also unsure of how to model a horn for a compression driver in HornResp. Especially for the Pyle PDS521 drivers there isn't much information on them (Qts, Qes, most, if not all, of the Thiele-Small parameters).
Art and Patrick - my apologies for misreading the thread. I think that there was so much data flying around that I warped myself into confusion 🙂
I think my caution with building my own HF horns is pretty much as Patrick has stated himself - I don't know if I'd have the tools or craftsmanship to be accurate enough. I could certainly try, especially if it's down to full or half millimetre measurements.
I'm also unsure of how to model a horn for a compression driver in HornResp. Especially for the Pyle PDS521 drivers there isn't much information on them (Qts, Qes, most, if not all, of the Thiele-Small parameters).
The crossover would have to be fairly high with this one to get the best of it. Elliptical horns don't lend themselves well to saving space and flat baffle mounting at the same time.
Attachments
So what driver do you use with this horn? It's fine with all the 1" drivers I use in it but yeah in my system it doesn't fit and if it did I'd use it for treble. It's really well made and sounds very nice for 26 bucks. How do you use it? The elliptical shape is better then round and as good as rectangular for "saving space" so I don't get what you mean (why does this matter?)
See the post linked below:
http://www.diyaudio.com/forums/subwoofers/119854-hornresp-412.html#post3793248
I think the horns I have will work for now, though that's not to say I wouldn't look into other avenues. I would eventually like to have a wider dispersion angle, but for now the narrow one would be Ok.
I had a quick attempt at bending the original tractrix horn (the one I'd made in cardboard that is longer, and has a smaller throat):
The mouth and throat dimensions are correct, but that bend on the inside of the curve is a bit wonky! I've not done anything to it, besides to bend it and check those measurements, so this may not work at all, or may be plausible.
For anyone who wants to play with this image, I'd set the dpi to 25.4, so that one dot represents a millimetre...
Edit: David, thanks for the info - that gives me something to play with!
I had a quick attempt at bending the original tractrix horn (the one I'd made in cardboard that is longer, and has a smaller throat):
The mouth and throat dimensions are correct, but that bend on the inside of the curve is a bit wonky! I've not done anything to it, besides to bend it and check those measurements, so this may not work at all, or may be plausible.
For anyone who wants to play with this image, I'd set the dpi to 25.4, so that one dot represents a millimetre...
Edit: David, thanks for the info - that gives me something to play with!
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