Over the past weekend at a Hackathon I have designed and printed a small MEH. I used ATH to generate the horn then simmed the HF and measured it to compare. I then also decided to add some midrange 2" drivers to see how it would turn out.
I am so happy with how it turned out for 1 weekends worth of work and not really any simming haha.
On the midrange measurements there is a big dip at around 1350hz the length of the horn is 120mm which would be half a wavelength from inside the compression driver to the horn mouth. Do you think that could cause the big dip at 1350hz then boost (1/3rd wavelength) at just below 2000hz?
The drivers I used were ones that were already here, it was two Faital Pro 2FE35 and a Lavoce DF10.172k which is way overpowered for the midrange haha. The rear chambers were made out of tape and hot glue.
This is the response after processing:
This is the unprocessed measurements:
The following are the polar plots (only up to 40 degrees each way)
Some pictures of the measuring process:
I am so happy with how it turned out for 1 weekends worth of work and not really any simming haha.
On the midrange measurements there is a big dip at around 1350hz the length of the horn is 120mm which would be half a wavelength from inside the compression driver to the horn mouth. Do you think that could cause the big dip at 1350hz then boost (1/3rd wavelength) at just below 2000hz?
The drivers I used were ones that were already here, it was two Faital Pro 2FE35 and a Lavoce DF10.172k which is way overpowered for the midrange haha. The rear chambers were made out of tape and hot glue.
This is the response after processing:
This is the unprocessed measurements:
The following are the polar plots (only up to 40 degrees each way)
Some pictures of the measuring process:
The sharp (high Q) dips ~2.6kHz & 3.6kHz may be the result of the out of phase reflection between the mid port holes and the virtual horn throat, which may be somewhere in the compression driver phase plug.
The mid response rises smoothly from 400 to 2kHz, other than the dip ~1.6kHz, which may be related to the geometry of it's enclosed "phase plug" (cone filler) volume.
Nice results!
I will do some more testing to figure that out.
That cancellation does match up with the length from the horn mouth to throat.
I might redo it but make the horn slightly longer, keeping all other dimensions. Testing if it is related to the horn length
That cancellation does match up with the length from the horn mouth to throat.
I might redo it but make the horn slightly longer, keeping all other dimensions. Testing if it is related to the horn length
The taps are 70mm or 80mm away from the compression driver from memory but will check later.
Which would be a cancellation around 2145hz maybe a little lower for the distance inside the compression driver at 80mm
It is a really short horn haha, 120mm length which is why they might seem further away
Which would be a cancellation around 2145hz maybe a little lower for the distance inside the compression driver at 80mm
It is a really short horn haha, 120mm length which is why they might seem further away
The area the midrange taps are in supported up to just below 2k, I think the cancellation at 1.3khz is also boosting 2k so rolling it off a bit later
This is tiny and not really suited for PA use, was more a test.
120mm x 120mm x 160mm not including drivers (Fit on a print bed in a single print)
120mm x 120mm x 160mm not including drivers (Fit on a print bed in a single print)
I think with 4 2FE22's it would have (just) enough SPL for home use.
Its smaller than I thought. Scaled up to 8" dia, one might even fit 2.5" or 3" drivers for more SPL...
Its smaller than I thought. Scaled up to 8" dia, one might even fit 2.5" or 3" drivers for more SPL...
I am planning on building a 2" version, 3" version and 4" version. See what frequency I can get up to with each.
I have tested in CAD for four drivers and I think the highest I would be able to push the 2" drivers to would be ~1861hz
area of 2703mm3 would be a wavelength of 18.43cm and 1861hz
(I would add the other two drivers)
With two drivers I think it might be possible to get 2.5k out the 2"
1474 mm3 would be 13.6122cm wavelength and 2520hz
Ports would be max 3.2cm away from each other across the horn
Ports are 4.3cm away from the compression drivers which should only cancel above 3khz (adding some distance inside the compression driver)
I will finish model and try printing it and measuring it, hopefully it will print well in one go on my printer
I have tested in CAD for four drivers and I think the highest I would be able to push the 2" drivers to would be ~1861hz
area of 2703mm3 would be a wavelength of 18.43cm and 1861hz
(I would add the other two drivers)
With two drivers I think it might be possible to get 2.5k out the 2"
1474 mm3 would be 13.6122cm wavelength and 2520hz
Ports would be max 3.2cm away from each other across the horn
Ports are 4.3cm away from the compression drivers which should only cancel above 3khz (adding some distance inside the compression driver)
I will finish model and try printing it and measuring it, hopefully it will print well in one go on my printer
I see little point in pushing higher than 1200-1500 Hz. Plenty of compression drivers will work well crossed over there.
The challenge is in how low you can go with only 2 small drivers with limited power handling and Xmax but I think the mids only need to go down to 400 Hz or so for crossover to woofer. Lower would be nice but 400 Hz would work for me.
I did a Bwaslo style wooden synergy back in the day so I know how tight it gets. His original synergy used cheap/tiny/buyout 1.5" drivers, long since unavailable and stretched to a 2.2 Khz XO, IIRC. The 2" Faitals are much nicer. The highly regarded SBacoustics 2.5in-SB65WBAC25-4 are much stronger if you can fit them. You don't need to close the backs if you seal the assembly in a box...
The challenge is in how low you can go with only 2 small drivers with limited power handling and Xmax but I think the mids only need to go down to 400 Hz or so for crossover to woofer. Lower would be nice but 400 Hz would work for me.
I did a Bwaslo style wooden synergy back in the day so I know how tight it gets. His original synergy used cheap/tiny/buyout 1.5" drivers, long since unavailable and stretched to a 2.2 Khz XO, IIRC. The 2" Faitals are much nicer. The highly regarded SBacoustics 2.5in-SB65WBAC25-4 are much stronger if you can fit them. You don't need to close the backs if you seal the assembly in a box...
The reason I am trying to get up to 2.5khz is it lets you use much cheaper compression drivers. I want to test out the Lavoce DF10.101L and Lavoce FSN020.71F which are about ~£15 each