Does anyone have experience using these?
EG,
PRV Audio WG 500 1.4" 140 degree W Line Array Waveguide 4-Bolt
Looking for a compression driver combo to mate with 12" midbass, purpose is for interior cinema/party purposes so I presume a wide horizontal dispersion and narrow vertical is advantageous.
After hours of searching the only horn that appears to be given the seal of approval from a hifi perspective is the 18sound xt1464. But looking at the plots, its -6db already at 30 degrees seems too narrow. The 'sweet spot' would be tiny and most of the 'crowd' would be hearing a steep 6-10Db step down as the omnidirectional midbass transitions to the narrow directivity of the horn.
The other thing that seems to have universal praise is the beyma TPL150. Its pretty hard to get and expensive though.
EG,
PRV Audio WG 500 1.4" 140 degree W Line Array Waveguide 4-Bolt
Looking for a compression driver combo to mate with 12" midbass, purpose is for interior cinema/party purposes so I presume a wide horizontal dispersion and narrow vertical is advantageous.
After hours of searching the only horn that appears to be given the seal of approval from a hifi perspective is the 18sound xt1464. But looking at the plots, its -6db already at 30 degrees seems too narrow. The 'sweet spot' would be tiny and most of the 'crowd' would be hearing a steep 6-10Db step down as the omnidirectional midbass transitions to the narrow directivity of the horn.
The other thing that seems to have universal praise is the beyma TPL150. Its pretty hard to get and expensive though.
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YMMV, but I've generally found that waveguides that are very asymmetrical sound weird due to pattern flip. You wind up with something that sounds tonally 'wrong' but you can't fix it with EQ because the sound is wrong due to the polar response of the system.
Line array waveguides are designed to be used in arrays, where the use of multiple units keeps pattern flip from being a problem.
Line array waveguides are designed to be used in arrays, where the use of multiple units keeps pattern flip from being a problem.
Apologies but how are line array waveguides any more asymmetrical than a horn? You mean deviation from a circle/square?
They have a large difference between horizontal and vertical dispersion. A narrow dispersion requires a large size along that direction in order to retain control. Usually asymmetric horns have wide horizontal coverage and narrow vertical, but their dimensions are large in horizontal direction and small in vertical direction. Hence they start losing control in vertical direction much earlier than horizontally, causing the real vertical dispersion to be larger than the horizontal one ('pattern flip') at the lower end of their working range.
I agree with Patrick that 'wrong' dispersion causes a wrong tonality that cannot be fixed.
I agree with Patrick that 'wrong' dispersion causes a wrong tonality that cannot be fixed.
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An externally hosted image should be here but it was not working when we last tested it.
A line array waveguide creates a very narrow asymmetrical beam. See how there's virtually no expansion in the width or height?
An externally hosted image should be here but it was not working when we last tested it.
In the PRV spec sheet, note that it doesn't list a horizontal coverage angle. This is because the horizontal coverage is typically defined by a SECOND waveguide. For instance, in this JBL Vertec speaker, the SECOND waveguide is defined by the walls of that waveguide in the center of the box.
So basically you have a series of devices chained together here. The first device is the compression driver. Then the waveguide from your original post. Then ANOTHER waveguide that it's bolted to.
The horizontal and vertical directivity is mostly defined by that second waveguide.
The main problem though, the one that you have to watch out for, is that line array waveguides aren't designed to be used as a single unit. I see this rule violated all the time, it's a big part of the reason that pro sound line arrays have such an awful rep. They're not mean to be used one unit at a time. They're designed to be placed in arrays. If you're not using at least 4-8 compression drivers in your line array, you're doing it wrong 🙂
The JBL setup in the picture is done correctly. On the left you have eight Vertecs in an array, a total of sixteen compression drivers. (two per box)
The setup on the right has six mid-high frequency units arrays together, a total of 12 compression drivers.
Lengthening the array will 'push' the frequency that the pattern flips lower and lower and lower.
A lot of the smaller arrays are already configured properly right out of the box. You lose the flexibility of being able to define the vertical coverage angle, but you don't have to deal with all the math of getting a pile of arrayed boxes to work properly. It's seriously rocket science to get sixty drivers to cohesively gel into a single wavefront.
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By the way, after going off on a complete tangent and ignoring your actual question, I should probably address that lol
If you want a speaker for home theater and parties with a narrow vertical beam and wide horizontal beam, something like the CBTs might be worth a look.
This is a tricky one though! I've heard the prosound CBTs and other prosound line arrays, and there's definitely some 'grunginess' to the sound. I think what's happening is that they're using dozens of small cheap drivers in an array, and it has a tendency to sound like, well, "a small cheap driver." So it sounds a lot like a very loud clock radio. It will get loud, the highs are pretty bad though. For a party, a lot of people wouldn't care. For home theater, it would probably get old.
The Parts Express "Epique" CBT basically takes the CBT idea but combines it with genuinely good drivers. So it still sounds like a big pile o' drivers, but those drivers are pretty nice and I think the speaker sounds excellent. I've definitely considered buying them for my own theater.
If you can live with the wider directivity of a conventional two-way, you can get shockingly loud with a simple prosound two-way. I'm talking about a 12" woofer combined with a 1" compression driver on a waveguide. There are a million of these for sale. Everyone from JBL to QSC to Celestion sells these. They are ubiquitous. I went to a nightclub a few months ago that was rocking the entire outside space with a pair of QSCs for the entire place. Waveguides and compression drivers and amplifiers have become really, really good lately and these designs are tough to beat imho. If you want to DIY, there are a lot of options too. I like the Geddes speakers. Not sure if they're still for sale?
If you want a speaker for home theater and parties with a narrow vertical beam and wide horizontal beam, something like the CBTs might be worth a look.
This is a tricky one though! I've heard the prosound CBTs and other prosound line arrays, and there's definitely some 'grunginess' to the sound. I think what's happening is that they're using dozens of small cheap drivers in an array, and it has a tendency to sound like, well, "a small cheap driver." So it sounds a lot like a very loud clock radio. It will get loud, the highs are pretty bad though. For a party, a lot of people wouldn't care. For home theater, it would probably get old.
The Parts Express "Epique" CBT basically takes the CBT idea but combines it with genuinely good drivers. So it still sounds like a big pile o' drivers, but those drivers are pretty nice and I think the speaker sounds excellent. I've definitely considered buying them for my own theater.
If you can live with the wider directivity of a conventional two-way, you can get shockingly loud with a simple prosound two-way. I'm talking about a 12" woofer combined with a 1" compression driver on a waveguide. There are a million of these for sale. Everyone from JBL to QSC to Celestion sells these. They are ubiquitous. I went to a nightclub a few months ago that was rocking the entire outside space with a pair of QSCs for the entire place. Waveguides and compression drivers and amplifiers have become really, really good lately and these designs are tough to beat imho. If you want to DIY, there are a lot of options too. I like the Geddes speakers. Not sure if they're still for sale?
Hey Patrick.... maybe this should be a separate thread, but one kind of thing I've toyed with is big, flat ESL's like Roger Sanders' models.
The issues are exactly what you would expect. A pinpoint sized listening location. In that place, it is magical, and 1mm away, not so much. Do you think something as simple as putting a cylinder in front of them, or even a pair of cylinders, would create a pleasant dispersion?
The issues are exactly what you would expect. A pinpoint sized listening location. In that place, it is magical, and 1mm away, not so much. Do you think something as simple as putting a cylinder in front of them, or even a pair of cylinders, would create a pleasant dispersion?
That's why the Martin Logan ESLs are curved. The curavature creates a curved wavefront.
So the Martin Logans have extremely narrow vertical directivity, virtually zero degrees. But their horizontal directivity is somewhere around 45 degrees.
They don't suffer from pattern flip because the diaphragm is so large.
Maybe the the question of the OP regarding asymmetry is because not everybody is aware of the way the term "asymmetric" is used when it comes to horns. Asymmetric in this context means the the vertical and the horizontal dispersion are not equal.
Regards
Charles
Regards
Charles
So I presume this pattern flip thing must also be an issue for any ribbon tweeters or AMTs used as a single unit?
I was thinking the beyma TPL150 was a no brainer if you could get them.
When it comes to DIY there are many options for compression drivers, but in terms of horns and waveguides there isnt that much, and then I have the extra issue that I have not much of a clue in terms of what to look for in a horn design, nor what tradeoffs I need to be aware of....eg, this pattern flip issue. Most of them are fairly narrow dispersion. The well regarded XT1464 has a smoothed shape (helps with diffraction?) which is absent from almost every other horn.
CBTs are out of the game as I prefer something sensitive, like 95-100DB/1W - keep the amp small.
I was thinking the beyma TPL150 was a no brainer if you could get them.
When it comes to DIY there are many options for compression drivers, but in terms of horns and waveguides there isnt that much, and then I have the extra issue that I have not much of a clue in terms of what to look for in a horn design, nor what tradeoffs I need to be aware of....eg, this pattern flip issue. Most of them are fairly narrow dispersion. The well regarded XT1464 has a smoothed shape (helps with diffraction?) which is absent from almost every other horn.
CBTs are out of the game as I prefer something sensitive, like 95-100DB/1W - keep the amp small.
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