In preparation of a big 2-way SEOS synergy horn project I thought it best to try out the whole synergy build with a cheaper horn and drivers. I already have a Xilica and the Faital PRO HF200 driver, so I only need the horn and the low freq. drivers.
Parts
For the horn I have chosen the P-Audio PH642 2" bolt on horn.
Low frequency drivers will be 2 (or maybe even ) 4 6" (or 6,5") drivers. That way I'll be sure they can be mounted on the horn. Yes, they will be quite outpowered by the HF200 driver, but as this is for testing purposes in HiFi use that's not really an issue. I'm planning on looking for drivers that can work down to the lowest crossover point this horn could manage, and this in a sealed enclosure. Size of the cabin is not really an issue at this poiny as this speaker will not be mounted.
Calculations and crossovers
I really have a lot of questions about the whole process, not all relevant to this initial try out project, but they are things I do need to know and consider when building the bigger SEOS horn. Some things I just needed confirmed, although I'm basing them on the big MEH K402 horn thread from Chris, so I know the info to be correct:
The position of the holes in relation to the horn mouth will be based on a distance 1/4th of the wavelength of the crossover frequency (500hz)
The diameter of the wholes will be based on a 1/10 ratio in relation to the woofer piston area
Not sure how the recommended minimum frequency of a horn needs to be interpreted. Is it the same as for a regular 2-way speaker, or does the unity design help lower this by any chance? Reason I need to know is because I want to use a SEOS horn in the end, but those get extremely big if I want to have their crossovers the same as my mains. They should be able to go down to 500hz, but they get extremely big. Only the SEOS30 gets down to 500hz. If I could use the SEOS 22 down to 500hz I would have a perfect horn because it's big enough to mount 10-12" woofers, but it has a crossover of 650hz. Any way this horn could still work with 500hz xover?
The build
I think the hardest part to get right is the drilling of the holes and mounting the woofers.
Drilling: what kind of tools would I need? Would an appropriately sized wood drill work? I can get up to a diameter of 40mm (1,57"). I could also cut it out with my jigsaw if thats more appropriate
Woofer mounting: I am planning on making a mounting board similar to the one Chris used for his MEH. What kind of adhesive would be easiest to use? I dont have any experience with this kind of stuff, so would really need some good input. Preferably something one can do without a lot of experience of expensive tools.
Testing
Once I have build the speaker, and have used my UMIK and Xilica to get the crossover setup I would like to rigorously test it, as this is the point of this project. What kind of test would I be able to do to confirm everything is working as I designed it?
Thanks for reading through! Hopefully I'm not too far off with my calculations, so I can start this build as soon as possible!
Greetings
Parts
For the horn I have chosen the P-Audio PH642 2" bolt on horn.
Low frequency drivers will be 2 (or maybe even ) 4 6" (or 6,5") drivers. That way I'll be sure they can be mounted on the horn. Yes, they will be quite outpowered by the HF200 driver, but as this is for testing purposes in HiFi use that's not really an issue. I'm planning on looking for drivers that can work down to the lowest crossover point this horn could manage, and this in a sealed enclosure. Size of the cabin is not really an issue at this poiny as this speaker will not be mounted.
Calculations and crossovers
I really have a lot of questions about the whole process, not all relevant to this initial try out project, but they are things I do need to know and consider when building the bigger SEOS horn. Some things I just needed confirmed, although I'm basing them on the big MEH K402 horn thread from Chris, so I know the info to be correct:
The position of the holes in relation to the horn mouth will be based on a distance 1/4th of the wavelength of the crossover frequency (500hz)
The diameter of the wholes will be based on a 1/10 ratio in relation to the woofer piston area
Not sure how the recommended minimum frequency of a horn needs to be interpreted. Is it the same as for a regular 2-way speaker, or does the unity design help lower this by any chance? Reason I need to know is because I want to use a SEOS horn in the end, but those get extremely big if I want to have their crossovers the same as my mains. They should be able to go down to 500hz, but they get extremely big. Only the SEOS30 gets down to 500hz. If I could use the SEOS 22 down to 500hz I would have a perfect horn because it's big enough to mount 10-12" woofers, but it has a crossover of 650hz. Any way this horn could still work with 500hz xover?
The build
I think the hardest part to get right is the drilling of the holes and mounting the woofers.
Drilling: what kind of tools would I need? Would an appropriately sized wood drill work? I can get up to a diameter of 40mm (1,57"). I could also cut it out with my jigsaw if thats more appropriate
Woofer mounting: I am planning on making a mounting board similar to the one Chris used for his MEH. What kind of adhesive would be easiest to use? I dont have any experience with this kind of stuff, so would really need some good input. Preferably something one can do without a lot of experience of expensive tools.
Testing
Once I have build the speaker, and have used my UMIK and Xilica to get the crossover setup I would like to rigorously test it, as this is the point of this project. What kind of test would I be able to do to confirm everything is working as I designed it?
Thanks for reading through! Hopefully I'm not too far off with my calculations, so I can start this build as soon as possible!
Greetings
Wait.. did you just said 'cheaper'? 🙄
I don't see the point to be honest. The HF200 can go low and is weaker on the top end. Wouldn't it make more sense to pair these 6" drivers with something that's better up there?
This speaker is not gonna make a lot of sense price wise 😉 Let me explain: I already have a pair of HF200 drivers and a Xilica, and I'm planning on buying a pair of HF140 and another Xillica for the SEOS synergy. The HF140 is the same driver as the HF200, but with a 1,4" throat, so compatible with the smaller SEOS throats. If this designs "works", I'll discard this synergy and up my game to the SEOS. I just want to try calculating and building (primarily cutting up a horn) something cheap before trying my hands on the more expensive stuff.
Makes sense?
Makes sense?
I know the HF200 and HF140, thanks. The smaller throat size does not make the driver more capable at the upper end. They aren't bad drivers but there are a lot better suited drivers for that. What is the goal you're trying to acomplish? Build a synergy horn just to have a synergy horn? What's the use? PA? Hifi?
That does not make any sense. That's like 'a bit pregnant'. You can't get a result from things you didn't do. The driver is not ideal and the horn is far from good either. At least not for this use. Such a horn has to be bigger, a lot bigger if you want to go that low. If you want something cheap to experiment with, use the proper size but make it out of plywood. For a start, a conical horn would make the most sense to experiment with and easiest to make.
Exactly! I've got a chinese copy of that thai horn and I can tell it does not work below 650-700Hz and starts to get a uniform dispersion at ~800-900Hz. And it droops at the top end somewhere, forgot where but too low, which makes it a bad choice for the driver since the driver got it's strong side not up there either. A horn isn't good for a synergy build just because it got flat sides.
This project could be useful for you to figure out what obstacles you will encounter when building a unity horn. I would keep critical components (like midrange drivers, locations and dimension of their entry holes, compression driver) identical to what you will be using in your full size project.
Yes! The learning experience will be invaluable, especially if you plan to tackle a SEOS30 later. You should refine the trial design as much as you can to get the most out of the experiment.
As to how low it goes, in any Synergy you will be using the horn lower than its pattern control limit frequency, and below where you get significant horn loading benefit. As you go lower, the woofers on the horn act more like direct radiators but with directivity determined by horn mouth size rather than by cone diameter. The bigger the horn the better but there is a limit as to how much horn you can fit or will be allowed to fit in the room.
All good and fine but the horn is really short. The middle of the cone will be only ~10cm away from the mouth. I mean, you can simply put the cones outside around the horn then. What use is it if the compression driver can already go down to 700Hz? Cones for 600-700Hz? That does actually not make any sense.
They will be used for HiFi. I'm basing the driver choice on a combination of price and a recommendation by Bob Crites who uses it in his 2-way Cornscala 2 and K402 horn. The SEOS horn I'm planning will eventually be used as a fullrange height channel. The other 7 groundlevel speakers will (hopefully) all full range big synergies with the HF200 drivers. I want to build this synergy because it would fit in nicely with the ground level speakers, and it would be more affordable and weight and size appropriate.
Making a horn myself seems out of my skill set. I'm always open to another cheap horn which could dig lower. Chris A once recommended me this horn (11" x 17" ABS 2" Bolt-On Long Throw Horn 90deg x 40deg For Many 2" Exit Driver | eBay), but I dont see any crossover for it, an it would cost 3x times the PH horn.
Reason why I want to use the 500hz crossover for this try-out, is for this exact reason. I want to get as close as possible to the eventual plan.
That does not make any sense. You don't need any of the dynamic range of the D200 and none of the good lower range - but you actually need a very good top end. Why would you use a 76mm diaphragm driver and a 2" if the range you need is much better suited for a 1" driver? They are better at the top end for a fraction of the cost and with a lot more variety of drivers. That's like using safety boots for a sprint. Yes, you probably can do that. Is it good? Yes, as good as the safety boots for the sprint.
The size of the PH642 doesn't get you close. If you want to get a close result, you need it in about the size of the original. Like it was already said here, you'll not get the results, you just gain the experience of the mechanical part. But for that a wooden horn out of plywood is a lot better suited because you can easily fix and replace parts, which you can not the same way in a plastic horn. That means, especally if you want to gain experience, this is not the a good way to start it. With the plastic horn you won't get the result and not much in experience.
A point source soundfield can be created with the sources proper being located away from the virtual source.
My point was putting the drivers outside the horn would not result in a Synergy point source. The point of putting woofers on a Synergy horn is not to get improved loading at LF but to get point source behavior; regardless of whether or not a point source soundfield can be created some other way.
From curiosity, what other way did you have in mind?
From curiosity, what other way did you have in mind?
The point source doesn't require the woofers to be close to the tweeters even though putting them close makes them a point source. The quality that defines a given point source will be its modes.
Eg. an actual point source would, after time have created a sphere of pressure of finite size around the source. If you instead recreate that same expanded wavefront by building a solid sphere covered in radiators it will behave the same from the outside point of view and have the same virtual source point.
Eg. an actual point source would, after time have created a sphere of pressure of finite size around the source. If you instead recreate that same expanded wavefront by building a solid sphere covered in radiators it will behave the same from the outside point of view and have the same virtual source point.
You actually do get a virtual point source with the drivers outside the horn (or even a dome tweeter, you don't need a horn for that). But that does not matter because the horn actually does not end that apruptly, the baffle does extend the horn and you can simulate, measure and hear the difference of having a horn with no baffle, a small or a big baffle.
But that does not matter because it was already mentioned to give a crap about the radiation pattern, you still get ~45° dispersion on the main beam with the drivers outside of the horn.
But that does not matter because it was already mentioned to give a crap about the radiation pattern, you still get ~45° dispersion on the main beam with the drivers outside of the horn.
that point of view is, I think, the basis for various beam forming technologies using a plane or linear array of radiators and a separate dsp and amp for each radiator. Also for curved CBT line array...
nc535, you are being ironic above, right? 🙂
Isn't ICG's assertion, that you quoted, partially correct? I am familiar with such speakers as the Yorkville Unity. In this case, the bass ( < 300 Hz) comes from a 15" woofer. But as long as the woofer is within 1/4 wavelength of the Unity horn, doesn't it still count as a virtual point source?
Isn't ICG's assertion, that you quoted, partially correct? I am familiar with such speakers as the Yorkville Unity. In this case, the bass ( < 300 Hz) comes from a 15" woofer. But as long as the woofer is within 1/4 wavelength of the Unity horn, doesn't it still count as a virtual point source?
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