8+4+1 larger standmount is my favorite concept. Not overly complicated to build, 8inch usually offers good bass extension.
I had 12MU and 21W already around waiting for the right project, and I got lucky friend of mine offered to lend me 9800 tweeter. From the very little info available on tweeter I understood this tweeter should sound exceptionally. With +-0.1mm Xlin it is needed to be careful with crossover frequency, and my preliminary target is 3000-4000 LR2. From previous projects with 12MU I know this midrange is fine with that Fc as well.
9800 and 12MU are off-centre to minimize diffraction effects. This also means I need to take the horizontal measurements from the both sides. Speaker orientation for the listening will be drivers in so this side of the horizontals will be optimized.
9800 got new faceplate to get closer to 12MU, CtC is 100mm and Fc~3500Hz. These are good ingredients for nice power response.
I chose tilted front baffle to enable LR2 crossovers for all drivers.
Hopefully I will have a time to measure the drivers for the crossover in coming weeks.
I had 12MU and 21W already around waiting for the right project, and I got lucky friend of mine offered to lend me 9800 tweeter. From the very little info available on tweeter I understood this tweeter should sound exceptionally. With +-0.1mm Xlin it is needed to be careful with crossover frequency, and my preliminary target is 3000-4000 LR2. From previous projects with 12MU I know this midrange is fine with that Fc as well.
9800 and 12MU are off-centre to minimize diffraction effects. This also means I need to take the horizontal measurements from the both sides. Speaker orientation for the listening will be drivers in so this side of the horizontals will be optimized.
9800 got new faceplate to get closer to 12MU, CtC is 100mm and Fc~3500Hz. These are good ingredients for nice power response.
I chose tilted front baffle to enable LR2 crossovers for all drivers.
Hopefully I will have a time to measure the drivers for the crossover in coming weeks.
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Nice combination. And good to see the 9800 getting some air-time -it's overlooked but still an excellent design. I wouldn't pay too much attention to the nominal Xmax; it doesn't tend to correlate too well with tweeters (assuming it even does with other driver types, which is debatable itself) so you're better off going with HD at differing drive levels. IIRC from using it in the past, within reason the 9800 can handle a bit more than might be believed, although its not ideal for those who like very low filter frequencies of course.
Agree. I will definitely measure the distortion. Troels used 9800 in some of his projects and went down with Fc to 2500 LR2 if I recall well.
12MU is 8ohm version, and this time I gave it 2l net volume. I am really really looking forward to hear this midrange sing again.
Regarding 9800 I was told it sounds increbibly well, no signs of cheap alu tweeters or soft tweeters. After listenng to Bliesma Be and Satori TXN I start to prefer hard domes, so I have high hopes in 9800.
12MU is 8ohm version, and this time I gave it 2l net volume. I am really really looking forward to hear this midrange sing again.
Regarding 9800 I was told it sounds increbibly well, no signs of cheap alu tweeters or soft tweeters. After listenng to Bliesma Be and Satori TXN I start to prefer hard domes, so I have high hopes in 9800.
markbakk: yes, I was thinking about chamfering or the rounding of the baffle around the T and M. Anything of it would lead to complicated construction, veneering and likely needing to paint the baffles instead of veneering. This is the project for the hifi friend and this was the compromise he liked.
Looks a really interesting project, which 22W are you using (8555?) and can you provide any more details of woofer box size/port tuning ? Thanks for posting , look forward to updates.
Thinking of it, arrangement of the two 8" drivers side by side requires baffle width ~500mm, this would move the frequency of the diffraction far below tweeter range, somewhere to midrange, and if 5-7" midrange is used (they are less sensitive to diffractions), plus mild baffle edge chamfering would nicely mitigate diffractions overall.
Today I installed all drivers to enclosure and measured FRs and distortion. Except front firing port making the troubles at 500Hz (I will take care of this) I am very happy, especially with:
Initial crossover look good, it is symetric LR2. M-T phase tracking could be good, baffle tilt is 7deg and 9deg would be better.
- 12MU linearity 500-3000Hz, perfect
- distortion measurement of 9800, even for 5.6V I do not see an issue to use it with shallow crossover slope.
- overall low diffractions thank to offsetting the drivers to one side of the baffle
Initial crossover look good, it is symetric LR2. M-T phase tracking could be good, baffle tilt is 7deg and 9deg would be better.
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My mouth is drooling. 🤤
How is the sample consistency between the different 21Ws or is this the same pair from before?
How is the sample consistency between the different 21Ws or is this the same pair from before?
I measured TS parameters of 21W, and as expected, they are much higher then datasheet TS. I also Installed additional magnets, which brought mild lowering of the Qs. 33l cabinet with ~31Hz port tuning looks good in the sim.
I optimized the crossover, and I hope I will get to the listening of these soon.
The second speaker is assembled and ready to be connected to the crossover.
Initial project writeup was published.
https://pkaudio.webnode.cz/21w-12mu-9800/
I optimized the crossover, and I hope I will get to the listening of these soon.
The second speaker is assembled and ready to be connected to the crossover.
Initial project writeup was published.
https://pkaudio.webnode.cz/21w-12mu-9800/
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Whah, the VAS and Qs are way off, looking even more like it wants a big closed box, but you said you tried that and still found it too lean sounding?
Nice project. 👍
Do you measure all Scan Speaks much higher than in a datasheet? And also after break in? I just measured 4 pieces of Revs 18W and they are also above 0.5 Qes....but cold from the box. I will repeat after they sing 20-100 Hz for a few hours...
Do you measure all Scan Speaks much higher than in a datasheet? And also after break in? I just measured 4 pieces of Revs 18W and they are also above 0.5 Qes....but cold from the box. I will repeat after they sing 20-100 Hz for a few hours...
Yes, in 2way I tried it in 37l closed, it sounded too dry, I missed the body of the instruments.
I recall 26w4867 had higher Qs and Fs. On the other hand 26w classic woofer has Fs only ~2dB off and Qs were almost same as datasheet Qs.