My idea was to find a venture capitalist and a company not in China that could clone these:
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Sorry for not checking in here with you guys. I've been bedridden for the last 2 weeks thanks to progressing health issues. Adding to that, our entire electrical panel went out and took out the AC condenser unit. AZ gets 30 deg C temps this time of year, so AC is very necessary. There goes another $24k...
I was helping @Troy Madden with his D7608 tuning. He got some decent results. I can't do too much right now being this way but I'm trying to finish a successful print on a pair of the rear chambers, which was repeatedly ruined by the flaky power issues we had.
I was helping @Troy Madden with his D7608 tuning. He got some decent results. I can't do too much right now being this way but I'm trying to finish a successful print on a pair of the rear chambers, which was repeatedly ruined by the flaky power issues we had.
I've started cutting the panels for the Peerless towers using 2x NE315Ws, 2x NE180Ws, 2x D7608s and 1x DA32TX. An alternate mid/tweeter combo would be Morel 2x CAM558 and 1x CAT378, which I'm leaning towards due to tighter CTC spacing. They can also be crossed higher from mid to tweeter, which is IMO more important. The mids already have chambers on them.
The NE180W are awesome midbass drivers. I'd say they're one of the best midbass under $100.
The NE180W are awesome midbass drivers. I'd say they're one of the best midbass under $100.
The D7608s can be difficult to linearize with a passive network on a wider baffle. Usually they need a slight negative LF shelf under 2.3k for BSC.
FWIW, I used Yamaha JA0801 domes in 18mm BB plywood waveguides cut directly in the baffle of a developmental model I'm working on. It's a 4-way hybrid dipole system with dual 12" SBA woofers + Satori WO24TX mid + Satori 29mm Beryllium tweeter. JA0801 is high-passed pretty high at 1000Hz LR2 & low passed at 4kHz LR4. The shallower slope creates cardioid directivity through the transition between low & high mid. So it's dipole below ~500Hz, cardioid to ~1500Hz, then monopole above. Not full dipole to reduce the effect of too much reverb at higher frequencies/volume in a big undamped room.
In my 420sf studio, it sounds great even at >105 dB/1m peaks. The dynamic quality of this system is outstanding. They love percussion but also have great richness/contrast with anything in the middle.
In my 420sf studio, it sounds great even at >105 dB/1m peaks. The dynamic quality of this system is outstanding. They love percussion but also have great richness/contrast with anything in the middle.
New dome mid from Dayton: https://www.parts-express.com/Dayto...d-Combo-Matched-Sets-4-Ohm-285-412?quantity=1
All the best to you, profiguy!
Here is a picture of the speaker project, this is a prototype cabinet ,I plan on something a bit more refined in the future. Currently crossing the mid at 700hz on the low end, and 4000hz at the top end. Much lower on the bottom end and the mid sounds distressed to my ears, at 500hz it doesn't sound near as clean, even though distortion measures fine. Using 4K at the top end to keep the tweeter well within it's comfort zone, and it does sound very clean and open. Tweeter is a Chinese brand "Mellow David", and has been tested as a very good performer elsewhere on this forum. Supposedly a beryllium dome but this isnt confirmed. I actually like it better than the SB beryllium dome, I have tried them as well, in other projects. Tried a decent fabric dome tweeter in this project and it just lacked resolution and clarity. I'm targeting 24db crossover slopes, but its a bit tricky with the mids limited bandwidth and my limited experience! But, so far, the speakers are probably the best mains I have had. Very clean and transparent sound, and deep and wide soundstage. Distortion is minimal, at 78db, which is about where I listen, 2nd order is just .06% and 3rd is a mere .029! This measured using a Umik 2. So far, so good! I have not quite got the baffle step comp just where I wanted but it's darn close, male and female voices are very realistic, perhaps just a touch lean. My reference music CD's sound better than I have ever heard them, and for movies, the 5th Element for example is just stunning! So thanks for your help so far profiguy and any additional tips from anyone is welcome as well. Click image to see full speaker.
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PMC describes the xover by the electrical circuit, not the acoustic rolloff. It is likely that the electrical slope is 4th order and the acoustic is higher by at least 2 orders.
I thought about that. But then a steeper slope means the mid is seeing more energy closer to the crossover point. I wonder how they keep it flat and clean that low? X-max is pretty limited, I wonder what the excursion is at higher SPL's?
This dome looks fantastic! A 2" you can cross over low and high and is "cheap". Sensitivity is a relatively low and power rating also but for HiFi it's plenty.
A pitty you can't remove the front plate. Routing a front plate with attached driver is ... a pain.
Some great info on back chambers for the Vifa version of the ScanSpeak 3" dome midrange..........https://diy.midwestaudio.club/discussion/1120/d75-chamber-sizing. https://diy.midwestaudio.club/discussion/1120/d75-chamber-sizing
All the experimentation is great to see, for sure.
But I personally would not make such a large volume back chamber. Yes, the larger chamber lowers Fs, but it also doesn't provide as much air pressure protection. Without high Xmax (like the Bliesma 34mms), I'd guess distortion will rise at lower SPL. The rolloff also has to start higher, much like what happens when you lower the Q of a sealed bass box below 0.7.
If a large back chamber is so beneficial, why don't ANY of the mid-dome makers use them?
The ones with the biggest chambers are maybe the Satori MD60N & the old Yamaha JA0801 beryllium. And they're not that big. Nowhere near 3" ID x 1.75"L or 3.5"L used by the main poster in that linked thread.
@profiguy made a comment a while back about how there's likely an ideal size AND shape for a back chamber. I've come to agree.
First off, the older D75MX Vifa mid is slightly different than the D7608. The MX-21 is the oldest 80s version and has a different dome composition. The MX-41 is a little closer, but it also has some differences in dome material and shape. These Vifa versions are not as accurate sounding and won't play as loud down low. The motor yoke venting is also different on the older ones. The SS D7608 has a much better dome design, both in profile and material, including the coating. Qms also measures higher on the SS version.
I've owned 2 pairs of PMC IB1s and can say without doubt the mids are slightly modified versions of D7608s. The only difference is the rear felt on the motor.
Below are measurements taken from Stereophile. These are in line with the system measurements I've taken a long time back.
PMC IB1 individual driver FR -
and impedance/phase plots -
The mids cross electrically between 500 - 600 hz but the higher Qtc of the mid shifts that down closer to 400 hz acoustical HP. The rear chambers are roughly 400 ml net on the IB1s with some heavier fiber material dampening the chambers. The upper end mid LP is also altered by the climbing acoustic response coupled with the baffle dimensions influencing the final FR. The other big influence on the system FR is the driver overlap gain in the mids.
I've owned 2 pairs of PMC IB1s and can say without doubt the mids are slightly modified versions of D7608s. The only difference is the rear felt on the motor.
Below are measurements taken from Stereophile. These are in line with the system measurements I've taken a long time back.
PMC IB1 individual driver FR -
and impedance/phase plots -
The mids cross electrically between 500 - 600 hz but the higher Qtc of the mid shifts that down closer to 400 hz acoustical HP. The rear chambers are roughly 400 ml net on the IB1s with some heavier fiber material dampening the chambers. The upper end mid LP is also altered by the climbing acoustic response coupled with the baffle dimensions influencing the final FR. The other big influence on the system FR is the driver overlap gain in the mids.
Thanks for suggesting the NE180W---prompting my search for it. I was surprised and happy to see that Parts Express has the NExxxW drivers back on order!
A sad story: With no proper supply available, my friend resorted to Ali-x---ss for some NE265W drivers, that turned out to be drastically out of spec (surplus/QC rejects?).
I have used the NE123W as a good lower-priced cone mid, it does pretty well. .
I have done a couple speakers recently with low-priced mid-domes and I have loved the natural presentation of voices and acoustic instruments. Both have added wave guide elements that help to satisfy my desire for a bit of forward directivity.
The domes have each challenged my advanced-beginner level of crossover design. Previously I have used easy-to-work-with cone mids.
Wishes to you, Profiguy, for your health. Thanks for all the sharing of your deep understanding of domes/systems. A google search dropped me into this thread at page #52, I have more reading to do!