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Multi-Way Conventional loudspeakers with crossovers

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Old 19th September 2013, 09:00 AM   #6051
AndrewT is offline AndrewT  Scotland
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in the UK we use: tan(angle)
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Old 19th September 2013, 09:53 AM   #6052
mabat is offline mabat  Czech Republic
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OK, sorry then to everyone who is not using the "tg" for this function.
Maybe it's just the former eastern block, I don't know, never bothered. Now I know one must be more carefull

BTW, did anyone check if it's right? I did but might make the same mistake twice...

Last edited by mabat; 19th September 2013 at 09:56 AM.
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Old 19th September 2013, 06:52 PM   #6053
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Default More Formula

Quote:
Originally Posted by mabat View Post
Maybe it has been here before, nevertheless here is the exact equation for OS contour for a non-zero entry angle (phi):

Click the image to open in full size.

I've derived it for myself to avoid the cut & try approach but it may be usefull for others as well. It really simplifies the process of generating the coordinates. Other variables are as usual.
Here are some additional formula that may be helpful as well.

[1] Smooth Joint Connection of a Compression Driver to An OS-Horn

[2] Smooth Joint Connection of a Compression Driver to An OS-Horn

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WHG
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Old 23rd September 2013, 05:54 AM   #6054
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Quote:
Originally Posted by mabat View Post
BTW, did anyone check if it's right? I did but might make the same mistake twice...
Hi mabat,

Rest assured - your formula is correct.

I have been using the same expression in Hornresp for years :-).

Kind regards,

David
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Old 20th October 2013, 04:22 PM   #6055
gtb is offline gtb  France
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I've read somewhere else that the deepest the horn, the more the honk. In case of the OS waveguide with foam, I would like to know which produces more HOMs ? The smallest or the largest ? The Harper or the Summa ?
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Old 20th October 2013, 06:03 PM   #6056
gedlee is offline gedlee  United States
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There may be some truth to the length issue. The longer the horn the lower in frequency the internal standing waves - along the axis - are. HOMs do not travel along the axis.

The HOMs depend on the flare of the device and the compression drivers match, not on its length, so there will be the same level of HOM's in both devices, BUT ... There is a difference in the mouth diffraction and the waveguides ability to control the sound radiation. The larger device has less mouth diffraction and it occurs at a lower frequency so it tends to be less of a problem. The really big difference is in pattern control. The larger waveguide controls to more than an octave lower than the smaller one. This has big effects on the crossover design and frequency location. The larger device just tends to have all of the performance advantages over the smaller one, but is, of course, larger and harder to package.

There are a lot of things going on in a horn, far more than most people understand or acknowledge and all of them seem to be important from a perception point of view. HOMs are one of those things, but hardly the only aspect that matters.
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Old 20th October 2013, 09:29 PM   #6057
Pano is offline Pano  United States
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Quote:
Originally Posted by gtb View Post
I've read somewhere else that the deepest the horn, the more the honk.
If this were true, then the big horns like the W.E. 15A f or Vitaphone 11 foot horns would have terrible honk. They don't. So there is something else going on, I suppose.
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Old 20th October 2013, 10:23 PM   #6058
soongsc is offline soongsc  Taiwan
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I have found it almost impossible to get satisfactory wide bandwidth out of horns. For example, if I could get 100Hz~20KHz with a direct radiating driver, trying to get the similar bandwidth with a horn to have higher SPL capability and a more unified wavefront across the band seems impossible. I have decided to go for a larger wide band driver instead, seems more achievable with a new cone design. I would probably go for horns in a 3 way design.
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Old 20th October 2013, 11:17 PM   #6059
gedlee is offline gedlee  United States
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Basically it is impossible to get very wide bandwidth from a horn. Just as it is impossible to get a wide bandwidth flat power response from any direct radiator regardless of size. There is no free lunch anywhere in audio.
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Old 21st October 2013, 12:47 AM   #6060
soongsc is offline soongsc  Taiwan
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It seems flat power response is not possible with horns, maybe you can make SPL over an angular range match the power response, but it is not flat unless you equalize it. Isn't this the case?
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