It seems like smaller radii domes benefit the most from a wg (i.e. 90 degree to flatish transducers), Is that correct? If that's the case, the phenomenal ring domes would potentially be the best candidates, correct?
The SB21 dome is actually nearly a half-circle, the SB26 is much flatter, so it didn't quite turn out that way. Ring radiators work well, but I think that has more to do with the phase plug of the Scans and Vifa. I'm personally not a big fan of the XT25, had it in my theater speaker for years, so I haven't bothered with it. The Scans would be more interesting.
More waveguides results! I just changed my soundcard so I can now measure out to 48khz and capture these metal dome breakups a bit better. I'll keep updating over the next few days as I have a lot of waveguides. Up first are the 5" waveguides.
I knew the CSS LD22 could measure a lot better with a smaller throat, and these results definitely prove that out:
Looks damn good!
Next are the RST28's. First the fabric dome with no phase shield:
Now the RST28A with the standard .25" diameter phase shield I've been using, it is about 1/8" from the dome:
Holy breakup! I think there is room to play with the PS to hopefully get a null to land on the breakup. I won't post all of the variations I tried, but I moved the PS closer and farther away, used a .47" dia PS, added an outer ring and played with ring size. The ring looks to be an improvement when comboed with the .25" dia PS, not so much when comboed with the .47" dia PS though it was the best result of any other .47" variant. Here are the best three results of the experiements I did:
And also the RST28A without a phase shield:
Will get the SB21 and SB26's up tomorrow, I now have three variants of the SB26: aluminum, ceramic/anodized Al, and fabric. I also have some 4" and 8" waveguides.
BTW, does anyone know how to setup wavelet analysis in SE?
Looking forward to sb26 fabric on 8" wg test :) Should be relatively high sensitivity result (with its top end peaking),narrow surround and high xmax. Could you maybe run HD sweeps for some of the bigger wg combos please?
Keep up the good work Brandon. This is all most interesting and enlightening :)
Somehow I managed to not get printed the newest 5" and 8" for the SB26 :( But since I have three dome variants now and can measure out to 48khz, I thought I'd revisit the 5" vG and 8" vC. None these will have phase shields as I already cut them off months ago.
First is the fabric dome SB26STAC:
Aluminum done SB26ADC:
Ceramic dome SB26CDC:
I wanted to revisit using an ellipse as the profile for the flare. Like this:
Interesting results, I'll have to dig into this later.
Next is the little SB21SDC:
And last, the 8" RST28 designs:
Up next will be some 4" designs. I see some value in a small waveguide used to cross higher to a smallish mid. Benefits: still matches mid directivity, allows mid to cover much of vocal range without a wonky polar response, acoustic centers align.
After that I need to play with phase shields in shims and see what happens. I'd really like to get lucky and notch out those metal dome breakups.
|All times are GMT. The time now is 10:06 PM.|
Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 17.65%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio