VituixCAD v2

[JonMarsh]

That's what I always do when that happens, anyway, but MS's "Nanny" efforts have become more annoying, and they don't even have a direct dialog choice for that- just a "Get Info" button. Well, I'm used to dealing with this BS, but it doesn't mean I have to like or admire it.

[Reet]

Do you know the math behind behind this?

up until recently I had gone with Jeff Bagby's suggestions

With a big basketball court at your disposal, you don't need math. Just measure yourself at many distances and compare, find the point where an increase in mic distance no longer affects the measured response. Realistically, the furthest you can place the mic to actual listening distance the better, 2m distance is more ideal but not practical in many rooms, big basketball court might be able to work though, of course with greater effort to hike the speaker up high and be able to rotate it safely and easily.

In any case, you'll find the 3x baffle width mentioned in VituixCAD measurement guide(s). Jeff's comment about 3-5x the driver width is about being "effectively in the far field", without consideration for the baffle size. That paper also is describing a single channel method with USB mic, so perhaps some generalization to prevent measuring the "on-axis" woofer response too far off-axis with mic located at tweeter axis, not driver axis.

[tktran]

Measurement distance is really up to you, there must be a balance as farther is better to capture real diffraction at listening distance, but closer is better as far as window length goes. 1m is generally a good distance for most speakers indoors, until you are building big cabinets where 3x cabinet width is >1m. Closer than 1m distance may allow for slight increase in window length, but quite minimal difference to actual measured data resolution.

Thanks for this. I spent the last few Sunday night at the local basketball court from 9PM to MIDNIGHT! taking measurements at great heights.
Which is great as far as low noise floor (30dB) and window lengths (>10ms) are concerned.


Except that setting and packing up takes SO LONG:


I'd rather do it from the comfort of my own spare room, but it's only practicable at about 50cm for a nice window length.

I would suggest, minimum 3x cabinet width. Size of driver is irrelevant.

Do you know the math behind behind this?

Up until recently I had gone with Jeff Bagby's suggestions from White Paper - Accurate In-Room Frequency Response to 10Hz.pdf (claub.net)
where I understood far field to be '>2 times cabinet width && >3 times driver cone diameter'

Only since when VituixCAD's Merger tool started merging with both the diffraction simulated far field (3-20m) using Diffraction tool, and measured distance at 1000mm have I changed my process...

[Reet]

Are there any problems of measuring at 50cm, or 2 ft etc, and adjusting the timing offset?

Measurement distance is really up to you, there must be a balance as farther is better to capture real diffraction at listening distance, but closer is better as far as window length goes. 1m is generally a good distance for most speakers indoors, until you are building big cabinets where 3x cabinet width is >1m. Closer than 1m distance may allow for slight increase in window length, but quite minimal difference to actual measured data resolution.

As long the measurement condition for being in the far field are met (eg. >2 times cabinet width && >3 times driver diameter)
Of course for really big speakers measuring out at 1m or more is better, but for tiny 2 ways...

I would suggest, minimum 3x cabinet width. Size of driver is irrelevant.

[Reet]

Just tell windows to take the training wheels off and install your software anyway.

FWIW Mac has a similar problem with software, they call it "notarization", so you also have to specifically allow installation of software that hasn't been notarized.