I'm still working on this, I need to build new cabinets to house the final design. I'm also thinking about ordering a KABD and making this a portable blue-tooth speaker. Anyways, here is the STL! I want to make an organized write up but I just haven't had the time. This simple/cheap MEH idea turned out to be a lot more work than expected.
Here are my DSP settings. I still need to take polars with these.
Tweeter (Inverted Polarity)
Gain: -3db
High Pass Filter: 1400 Hz, Butterworth, 24 dB/oct
Low Shelf EQ: 4200 Hz, -9.2 dB, Q 0.9
Woofer
Gain: 0db
Low Pass Filter: 3000 Hz, Butterworth, 6 dB/oct
High Pass Filter: 65 Hz, 12 dB/oct (slope type unspecified)
High Shelf EQ: 450 Hz, -11.5 dB, Q 0.9
The high pass on the woofer is optional but recommended. I turn it off for low volume listening. At higher levels it reduces port chuffing.
Tweeter (Inverted Polarity)
Gain: -3db
High Pass Filter: 1400 Hz, Butterworth, 24 dB/oct
Low Shelf EQ: 4200 Hz, -9.2 dB, Q 0.9
Woofer
Gain: 0db
Low Pass Filter: 3000 Hz, Butterworth, 6 dB/oct
High Pass Filter: 65 Hz, 12 dB/oct (slope type unspecified)
High Shelf EQ: 450 Hz, -11.5 dB, Q 0.9
The high pass on the woofer is optional but recommended. I turn it off for low volume listening. At higher levels it reduces port chuffing.
Thanks for your work, making MEHs accessible is a very noble thing to do 🙂 I saw that there a different versions of the XT25 tweeter, which one do you use? is it the Peerless by Tymphany XT25TG30-04 one from the picture?
Thank you again!
Thank you again!
@amori yes the Peerless by Tymphany XT25TG30-04 is the one I am using. There are other tweeters that will also fit but untested.
XT25BG60-04: The dual ring version. Will probably have similar performance. It's a lot heavier though so I would find a way to support it in the cabinet if possible. It will also require a deeper cabinet.
DX25TG59-04: The dome version. I really want to try this one. From what I have researched, the extra surface area of the dome could assist in achieving a low crossover frequency. However, I am skeptical on the high frequency performance > 10khz
Other candidates that might work but would require mounting/throat modifications: DC28F-8, RST28F-4. I wanted to try a bunch of these, but I quickly realized that I could buy a nice set of compression drivers with the money instead.
If anyone is interested in experimenting with one of these tweeters I can give you a file with updated mounting holes.
XT25BG60-04: The dual ring version. Will probably have similar performance. It's a lot heavier though so I would find a way to support it in the cabinet if possible. It will also require a deeper cabinet.
DX25TG59-04: The dome version. I really want to try this one. From what I have researched, the extra surface area of the dome could assist in achieving a low crossover frequency. However, I am skeptical on the high frequency performance > 10khz
Other candidates that might work but would require mounting/throat modifications: DC28F-8, RST28F-4. I wanted to try a bunch of these, but I quickly realized that I could buy a nice set of compression drivers with the money instead.
If anyone is interested in experimenting with one of these tweeters I can give you a file with updated mounting holes.
I think that if he had used an accelerometer rather than a microphone he may have found quite differently. The shape of the surfaces would also strongly affect resonances and more importantly, how sound gets radiated from surfaces. His example wasn't a horn with a driver mounted on a wall. His test may show not much radiated effect where the mic was pointing at with his tight small box, but not really anything that could be generalized on. When I tested, the issue was way past just measurable (with accelerometer), it was unlistenably buzzing with only moderate infill. Which was sad, because those were my cleanest horn prints and had to be thrown onto the trash pile.
I remember seeing that video a while back and tend to agree that the data is probably not applicable to MEHs. There's just a lot more energy being transmitted into the horn as you start going lower in frequency in a MEH, so the potential for material induced nonlinearities increases drastically.
I'm curious if there's interest in a sort of standardized testing rig for getting good repeatable data on that topic though. Something like a horn that could be compared against a plywood control to determine exactly what effect material/infill density/infill pattern has acoustically.
I have a CNC, several 3d printers, and a load of different drivers so would be happy to lend services there if there's some consensus on exactly what data would be useful to capture, and what a test device/platform might look like.
I'm curious if there's interest in a sort of standardized testing rig for getting good repeatable data on that topic though. Something like a horn that could be compared against a plywood control to determine exactly what effect material/infill density/infill pattern has acoustically.
I have a CNC, several 3d printers, and a load of different drivers so would be happy to lend services there if there's some consensus on exactly what data would be useful to capture, and what a test device/platform might look like.
Sigh... I'm convinced. I hear a very slight buzz at higher volumes. I was thinking it was my tweeter and have been driving myself crazy trying to fix. Will order a bigger nozzle and see if it improves things at some point. Maybe I can print it in ABS and give acetone smoothing a try.
I am also planing on gluing 6mm plywood triangles to the flat areas around the horn to fix what I got. That might help a bit.
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I am using the exact same printing technique for my SH60 clone as shown. The biggest difference being that the 3d printed section is crossed around 350hz. No buzzing is present in this design, probably due to the fact that there is less stress being but on it.
