Modula MT mkII inspired rework

[ergo]

My friend had Modula MT MKII sized speakers with Seas W18NX001 and Seas T29CF001. Tweeter in a more traditional mounting. As he likes how my Modula MT MKII version sounds we decided to upgrade his too. I still had two of the original MCM waveguides stashed away, so these went into the project now. We did have them 3D scanned before putting in the speakers to have the profile handy just in case I'll want to repro these again one day.

[ergo]

Over weekend I did also the measurements... several times in end. That's mainly as I had struggled for a long time to get ARTA to give me true absolute SPL reading when I use a 2 channel measurement. So I spent more time messing with ARTA calibrations than actual speakers. I did get CLIO and ARTA to agree reasonably close in end with about 2dB delta. Wrote an instruction of the process for myself too, so if anyone is interested I can share that too.

Anyhow, the below is also done using the new minimum phase features in VituixCAD. Looks pretty good, but I'll give it a go still next week. Perhaps there is a sweet spot still that will move the phase even closer. It is about the same as I achieved on mine, so should be good as is already

[---k---]

Cool project. Nice drivers, should sound good.

I've heard too many horror stories like yours of trying to get measurements to work, which is why I've probably always been a wimp and never done them for myself. So, give yourself a pat on the back for getting measurements done. :T

So, you're keeping the drivers the same; just adding a waveguide and redoing the crossover? Did you take measurements of the old system first? I'd be interested in seeing the before and after to try and understand how the waveguide improved it. With waveguide, you'll probably need measurements both on axis and off axis.

[ergo]

This is how it looked like before WG. Back then I did not do quite as many off axis measurements, but more than off axis already as shows

[ergo]

I did progress last weekend and finished the rewamp of my friends speakers.

One of the goals was to validate the measurement -> VituixCAD -> Xover build process.

a) I measured the tweeter and woofer at tweeter axis at 1m and nearfield at 0...180 degree horizontal plane.
b) Measure the tweeter and woofer wired in parallel
c) Measured nearfield responses
d) Merged the near and far field of woofer with VituixCAD baffle simulation
e) Created minimum phase versions of all measurements
e) Loaded the woofer and tweeter data to VituixCAD drivers
f) Loaded the "Reference angle overlay" and adjusted the Z axis to match the measured response of both drivers in parallel
...
Xover simulations and build and the verification measurements to make sure it does match reality

[ergo]

The measurements above are with short gating, so that is why the low end does not match but it does do it quite well above 1kHz.

I also remeasured my own Modula's versus the new version. At 0deg on axis the Seas tweeter is not quite as flat, but 20+ degree off axis it seems even a bit smoother.
Correction for right side measurement plots - tweeter is T29CF001

[5th element]

The measurements of that look extremely good, I'm guessing that they sound excellent!

Are you sure that you're working with the T25CF001 tweeter though? The surround looks quite a bit wider than I thought that tweeter had. Hmm maybe SEAS have changed things.

[ergo]

Correct you are sir - thank you for correcting me. It is the T29CF001 the Nextel coated one.
It was several years ago when we did the first version and it seems I somehow had frozen the 25 into memory instead of 29.

[ergo]

We did a listening session with my friend on Monday at my place. I have a bigger family room with open plan to other rooms and getting the speakers some 80cm off the back wall the sound was very good and we both liked it a lot. I had a pair of 3 ways to compare and those of course reached lower in spectrum, but these hold their own with imaging and how clean they sounded in mid/high range.
My friend has now been listening to them at home. Hes still happy but as he lives in a flat where the room is only 3m x 5m and basically all concrete the sound suffers much more. But he says it still is a big step up compared to before.

[Evil Twin]

You have done your friend a great service, as well as further advancing your own skills and experience....

This general system concept has considerable potential and there is further work in progress with another... though stalled at the moment due to core life issues.