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gazman
Registered User Joined: 30 January 2006 Status: Offline Points: 100 |
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Cheers for the reply Arthur, some interesting stuff. Quite curious about these drivers indeed, btw have you measured a DE250 against these on same horn at all? Would be interested in figures on that as I like the sound a lot. The website figures (albeit on two completely different horns though) have the Beyma CP380M with 2nd HD about 45dB down from fundamental and the BMS graph shows the 4550 with 2nd HD about 32dB down.Interestingly the coaxial 4594ND, 4595ND and 4592ND all have 2nd HD barely 22dB down from fundamental near the high end (6k up). Only thing I'd heard about those was comments claiming distortion was too bad to drive them down to their recommended 400-500hz but the distortion levels seem to get lower (around 40dB down) as far as 600hz.
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Calitri
Registered User Joined: 02 November 2004 Location: Finland Status: Offline Points: 132 |
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What is interesting about the coaxial design is that B&C also is doing a version of their own, so perhaps the idea is not as bad as I/you might think. Well, if you look at the B&C version's distortion, heh, now that's a high distortion figure!
Like I said in my previous post, I've only done measurements in practical situations, so there's always something else that might cause the feeling of a good sounding unit. Perhaps it's because in large format systems you need quite clinical drivers so that they have enough throw and the sound gets better with a little bit more distance to the speaker. This is just what I've experienced when doing concerts outside. When I heard the F1 Res4 + F218 set in small inside space, they did sound a bit harsh but clean and crystal clear, just as the line array using the BMS top end. But go outside when there's more that 5m distance to the closest speaker and it really starts to sound good. So that's why I don't always look at the HD figures because they're close range measurements, not from a distance and they don't always tell the truth in real situations. But like I said, that's just what I've experienced, so here's my 2 cents! |
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moray james
Registered User Joined: 07 September 2005 Location: Canada Status: Offline Points: 141 |
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Calitri: you said "What is interesting about the coaxial design is that B&C also is doing a version of their own" Do you have a link or url to this information? I took a fast look at B&C but did not see anything. Thanks.
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moray james
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Calitri
Registered User Joined: 02 November 2004 Location: Finland Status: Offline Points: 132 |
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It's right under the HF drivers, the DCX50, it's a new design, I believe someone else put the link here also... Anyways, here's the link.
http://www.bcspeakers.com/index.php?sez=1&categoria=4&id_descrizione=46&prodotto=199&id_descrizione_prod=54 |
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bassmish
Young Croc Joined: 28 October 2007 Location: MAAAANCHESTER Status: Offline Points: 1333 |
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Hello,
I'm not entirely sure what the problem that was intended to be solved by this design was, which makes this a bit pointless, and I'm also not sure if this is what steve B was saying. But. I think what's happening from looking at the picture is that the sound is no longer sent through a horn to present an acoustic impedance, but rather sent around a symmetrical (about the horiziontal) object/waveguide. This waveguide will have dimensions so as to suite the frequencies being transmitted as steve said (smaller than the wavelength?), e.g to eliminate standing waves, not to decrease HF response. The sound passes around the symmetrical object, then is presented with a large acoustic impedance in the form of a 1'' slit/hole. It is forced out of this slit and spreads out, at which point the horns take over combining the two sources in a clever way. Is this what you were saying/obvious? Bassmish |
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H..
Registered User Joined: 07 August 2007 Location: Thailand Status: Offline Points: 197 |
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Slot tweeter on a horn then!
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boab
Registered User Joined: 21 June 2004 Location: Busby Status: Offline Points: 484 |
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I think that the key may be in the statement...
"The Paraline element is a horn configuration that provides an effective impedance transformation while at the same time providing a way to adjust the path length in a continuously variable way, such that the high frequency dispersion pattern produced has the same characteristics as that of a much deeper horn." http://vtcproaudio.com/ |
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bassmish
Young Croc Joined: 28 October 2007 Location: MAAAANCHESTER Status: Offline Points: 1333 |
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maybe, the c'haracteristics of a deeper horn' are just refering to the way sound becomes more omni directional as the frequency decreases, but using this slit and a lot of pressure created by the dimensions of the waveguide, the sound will perform as a 'deeper horn' and spread out a large amount more? Sounds quite wrong.
I guess that a non variable path length would just be like a straight tube, so maybe adding a few 90 degree corners creates lots of disturbance in the path taken by the wave and consequently creates a continuously varying path length. maybe this unstability in the path taken by the wave causes a higher pressure inside the wave guide, hence they said, 'such that the high frequency......' |
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_djk_
Old Croc Joined: 23 November 2004 Location: United States Status: Offline Points: 6002 |
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"the c'haracteristics of a deeper horn' are just refering to the way sound becomes more "
No, it means the the length of the horn using the same driver would have to be much longer with a conventional throat construction.
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djk
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bassmish
Young Croc Joined: 28 October 2007 Location: MAAAANCHESTER Status: Offline Points: 1333 |
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thats not what I'm on about , just gaining the same performance of a conventional throat horn from a smaller design is not all that this thing does apparently. I was refering to a similar effect of the spreading out/diffraction displayed by light as it passes through a slit, or water through a hose pipe when you squeeze the end.
And, a conventional throat horn would not have a variable path length, or would it, what is the meaning of a continuously variable path length? |
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Calitri
Registered User Joined: 02 November 2004 Location: Finland Status: Offline Points: 132 |
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Just yesterday had an idea about the "deeper horn" part, could it refer to the fact where in normal line array horns the waves from the center of the horn would have to pass the same distance as the sides to create a vertical plane of sound, which is usually done by bending the center path. So perhaps the horn's throat refers to that difference. So instead of say 20 cm long line array horn you can have 2-4 cm long "horn" that creates the same kind of vertical plane, which in my mind brings the question that could it be just a simple Fresnel lens type thingy? It does exactly that type of result but with light so it just might be the same idea adapted to sound...
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bassmish
Young Croc Joined: 28 October 2007 Location: MAAAANCHESTER Status: Offline Points: 1333 |
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I'm doing an experiment on fresnel diffraction at a slit next week for my course, sounds relevant, best have a look at that!
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