Xtro flare redevelopement thread |
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cravings
Old Croc Joined: 30 January 2007 Location: Ireland Status: Offline Points: 7441 |
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to put a phase plug in the original straight horn.. you'd need to totally change the start of the horn to accomodate the plug, therefore the geometry.. it's a begin again project really isn't it?
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toastyghost
The 10,000 Points Club Joined: 09 January 2007 Location: Manchester Status: Offline Points: 10919 |
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You can change the response with EQ but only in one position - if your directivity is way off at certain frequencies then you aren't going to fix that with filters, especially if you're not a serious whizz. |
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Teunos
Old Croc Joined: 23 November 2008 Location: The Netherlands Status: Offline Points: 1799 |
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Its funny how many (fundamental) mathematical errors are in that paper. (I did not click on the link but i assume this is the peavey document?) Also, if you start drawing out the (correct) equations and throw them into a simulator, you will probably find out pretty quickly why it really isnt all that amazing. |
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Best regards,
Teun. |
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ceharden
The 10,000 Points Club Joined: 05 June 2005 Location: Southampton Status: Offline Points: 11776 |
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I would imagine a QTW can't be worse than just a straight conical waveguide without a smooth transition at the throat?
I did start doing some experiments a couple of years ago with the fibreglass versions of the Xtro flare. I modified the throat from square to closer to rounded and trying to add Martin Wavefront style 'Phase Balls' although I was only making them from Polystyrene and probably weren't rigid enough. Loaded with a an 18Sound 8M400 it did work fairly well. I can't remember what the high extension was like. I've still got the ones I started modifying if anyone wants to pick up the project because I can't see me doing it any time soon. |
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Mark James
Old Croc Joined: 15 January 2006 Location: rig side Status: Offline Points: 5309 |
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how much?
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me so horny me love you long throw
horn loaded for her pleasure |
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krestudon
Registered User Joined: 23 August 2011 Location: Madrid Status: Offline Points: 32 |
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Do you still need measurements on a B&C 8pe21?
I'm available.
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gen0me
Young Croc Joined: 20 February 2016 Location: UK Status: Offline Points: 999 |
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Thanks krestudon, I have them already.
What inspires me now is this: http://www.bluearan.co.uk/index.php?id=SONMR8XT&browsemode=manufacturer Dont know how much of it is true(even italians dont have that nice dispersion chars). Ofc scale is high to blind eye but it should be doeable anyway! Here are some of my tries: https://drive.google.com/drive/folders/0B5y23T8xURtGNmZwVlRsM3pmeXM?usp=sharing Mostly on the blind shoot. I was trying to do hornresp one(that would guarantee similar power on all the bandwidth) with very fast expanding after throat. Ofc hornresp sim has huge circumference value(from 43cm2 to 161cm2 in 3mm) but to do at lest something similar or go this way. Suprisingly this short phase plug that allows fast expansion after throat dont look so good on Abec sims. Edited by gen0me - 01 June 2017 at 12:12am |
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Teunos
Old Croc Joined: 23 November 2008 Location: The Netherlands Status: Offline Points: 1799 |
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Normalized directivity plots would be way more useful.
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Best regards,
Teun. |
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gen0me
Young Croc Joined: 20 February 2016 Location: UK Status: Offline Points: 999 |
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Thats for 40V Distance almost 4m. Hmm smt doesnt calculate.
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Teunos
Old Croc Joined: 23 November 2008 Location: The Netherlands Status: Offline Points: 1799 |
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Normalized means that everything off axis is eqed such that the on axis frequency response in the directivity plots is constant.
This way, you actually see what the horn geometry itself does to the directivity. If you have a huge peak on axis, it will also show off axis. Of course you would want to research the reason for this peak and battle it, but shallow trends still give twisted results. |
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Best regards,
Teun. |
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gen0me
Young Croc Joined: 20 February 2016 Location: UK Status: Offline Points: 999 |
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Need to figure out how to do it in abec.
I need some help in interpretation of the resaults. Is it possible that vertical and horizontal angles of horns influence dispersion from around 1.6, 1.8 kHz and lower much more important is mouth shape which works kind of against(verticaly wider, horizontaly narrower)? Top printscreens are horizontal, bottom vertical. Next one. |
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Teunos
Old Croc Joined: 23 November 2008 Location: The Netherlands Status: Offline Points: 1799 |
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Read up on Huygens theory and imagine how it would affect sound.
If the source is small compared to the wavelength, the source will become omnidirectional. If the source is much larger than the wavelength, it will automatically be directional. Typically you have 3 regimes that control directivity.
In your horn, which i guess is around 50cm wide, the point where the flip between 1 and 2 occurs is roughly around the 400~500Hz ballpark horizontal and higher for the vertical. This means that you will never, ever with these horn sizes, get a horn that is directive to below this frequency region. This shows in your simulations. What your simulations also show, is that in this area (500Hz), the directivity decreases, typical midrange waste-banding behavior. I do need to add, that this might be exaggerated a bit since around 700Hz your on-axis sensitivity is higher. What your simulations also show is that this effect is much worse in the vertical plane than in the horizontal plane. This is logical, since your horizontal termination to the open air is WAYYYY more smooth than that for the vertical, which is basically an open ended pipe. The funniest part of this all to me, is that most people have no idea that these effects exist. If you listen carefully to a sound system, you can spot them though. Especially when you stack multiple horns side by side, things like this can become problematic pretty fast. It is THE main difference between a professionally engineered cabinet and a home built DIY system. Measuring frequency response never tells you the entire picture, and you have found that out for yourself, kudos!
Maybe this clarifies why i always recommend people, that if you can stick with one speaker per side with a wide coverage angle (they are way easier to design, and the horns are automatically more constant directivity since the transition from 1>2>3 is way more smooth (physics, yeah!!)), than it is something you should always do i.m.o. Hope you find some helpful point in this post. Edited by Teunos - 14 June 2017 at 7:59am |
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Best regards,
Teun. |
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