SB12NRX25-08 4" woofer and SEAS Prestige 27TFFNC/G 1" tweeter. You can see it was a little windy today reflected in the low frequency response. Volume for woofer is a tad under 2 liters. Tweeter is just setting between strips of open cell foam, but I have determined where it will sit in relation to the front edge now.
No wires will exit the rear in the final speaker, they will be active and wireless stereo. Building a base to house the amps and power supply is next. I turned all the pieces by hand on the lathe. The wood is Spalted Maple with all kinds of worm holes and bug tracks, I could stare at it for hours lol. It has all been molded with extremely hard epoxy before turning, and is generally 3/4 to and inch thick. I wanted the effect of blowing through the wood and seeing into the speaker in some spots, very happy with the result. More layers of epoxy will be dumped over it before it's finished, definitely not going to leak anywhere lol
Crossover is 18db/oct Butterworth at 1800hz on the tweeter and 24db/oct LR at 1600hz on the woofer. The resulting acoustic crossover point is 24db/oct at 1500hz. These measurements are at 50 inches. Only the measurements at 150 and 180 degrees have a significant dip, and up to 60 degrees off axis it is practically omnidirectional up to 5000hz. The VituixCAD data is for 0-180 degrees.
I'm sitting between them in the nearfield on my shop bench as I write this and thoroughly enjoying it.
No wires will exit the rear in the final speaker, they will be active and wireless stereo. Building a base to house the amps and power supply is next. I turned all the pieces by hand on the lathe. The wood is Spalted Maple with all kinds of worm holes and bug tracks, I could stare at it for hours lol. It has all been molded with extremely hard epoxy before turning, and is generally 3/4 to and inch thick. I wanted the effect of blowing through the wood and seeing into the speaker in some spots, very happy with the result. More layers of epoxy will be dumped over it before it's finished, definitely not going to leak anywhere lol
Crossover is 18db/oct Butterworth at 1800hz on the tweeter and 24db/oct LR at 1600hz on the woofer. The resulting acoustic crossover point is 24db/oct at 1500hz. These measurements are at 50 inches. Only the measurements at 150 and 180 degrees have a significant dip, and up to 60 degrees off axis it is practically omnidirectional up to 5000hz. The VituixCAD data is for 0-180 degrees.
I'm sitting between them in the nearfield on my shop bench as I write this and thoroughly enjoying it.
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Thank you gentlemen. I should mention the measurements are not gated and 500ms. The low end gets a couple db boost when they are inside. Impressed by these 4" sb woofers, I can play them plenty loud even with electronica and they remain clean.
Inside at 1 meter vs outside at 50 inches shows the low end lift of the reverberant field indoors. Outdoors it's flat at 15 degrees off axis. Low shelf baffle step compensation is currently 2.5db beginning at 630hz. May be up another half db once I'm done voicing it, not sure yet I like the way it sounds as it is and I tend to listen off axis.
Tweeter delay is 0.13ms. Both measurements are 500ms. Once again, ignore below 80hz outside as it was a bit windy. I'm wired in a way that makes me sensitive to brightness for some reason, and these even tame bad recordings due to the minimal tweeter housing and low crossover point. They do an excellent job of disappearing into the sound field no matter how close I sit, or whether I move off axis or not. Scheming on the sub section now with a crossover around 200hz.
Tweeter delay is 0.13ms. Both measurements are 500ms. Once again, ignore below 80hz outside as it was a bit windy. I'm wired in a way that makes me sensitive to brightness for some reason, and these even tame bad recordings due to the minimal tweeter housing and low crossover point. They do an excellent job of disappearing into the sound field no matter how close I sit, or whether I move off axis or not. Scheming on the sub section now with a crossover around 200hz.
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Only able to work on it sporadically, but this project is coming to conclusion. Mount the sub amps and put a finish on them, we'll be good to go. Gotta hit the hay now, but thought I'd throw some pics up. Details and final measurements to come shortly
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Beautiful speakers. I bet they sound great too. Measurements look awesome. Great job on reducing diffraction with the rounded exterior shapes. What are you using for amps and DSP? Is it all housed in the rectangular box below?
Thank you xrk971, and cheers to you. They are dayton dspb250. Not available anymore and I hit a good deal on some before they went out. I also added micro usb to the power supply in order to run tinysine tws bluetooth receivers, but unfortunately I cannot recommend them because of the noise levels. I'm going to try running them through the sub inputs and see if I get the same issues.Beautiful speakers. I bet they sound great too. Measurements look awesome. Great job on reducing diffraction with the rounded exterior shapes. What are you using for amps and DSP? Is it all housed in the rectangular box below?
Yes, the power supply, amp and buck converter for usb power are all housed in the rectangular base, mounted on coated aluminum perf plate. The vent visible in the upper rear has a match in the bottom front, and I bent the ends of the perf plate up to give clearance for air cooling. Power supplies are mean well LRS-150 if I remember correctly. I've got maybe $70 per side into the power amp section lol
By flattening the tweeter housing a bit, I managed to get close to 1/4 wavelength at the crossover frequency, but not quite there at around 4". They are extremely detailed, but not sharp. Vocals are very intelligible, soundstage is precise, and they pull a magic disappearing act. When I stand right between them it's like headphones, but right in front of me, not in my head. Sound excellent even standing behind them, the image is just pushed out further to the front.
I've realized I would need around a 900hz crossover point when using a 4" in order to completely eliminate the dip in the rear hemisphere and create something with uniform polar response out to 5000hz. Ze ekzperiments muzt continue!
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Appreciate that LewinskiH01. Tough question. I originally set out to make the most compact wireless system I could, and although I'm running these with stereo 8" Ultimax subs crossed at 200hz right now and not missing any bass, I'm not sure whether I will use them that way in the end. They make very good nearfield desktop speakers when run full range by themselves. They are much smaller than the dipoles I have built, better suited for smaller rooms and more forgiving of placement. I have to say they do share many of the qualities I like in dipoles however, as well as Linkwitz's Pluto. But they have higher WAF factor, are easy to use and will find their way into many more rooms without objection I think.
Guess I will have to build a dipole now and do a side by side comparison 😏