diyAudio

diyAudio (https://www.diyaudio.com/forums/index.php)
-   Multi-Way (https://www.diyaudio.com/forums/multi-way/)
-   -   Open source Waveguides for CNC & 3D printing! (https://www.diyaudio.com/forums/multi-way/318190-source-waveguides-cnc-3d-printing.html)

Gaga 20th February 2018 09:00 PM

Hi Brandon,

Quote:

Christoph> if you get a chance, work the sim more on the SB26ADC. Of interest: a shim at the throat to move the dome back, vertical wall radius, and to a lesser extent the horizontal wall radius - though I feel that is pretty right on.
Will do so. Try to do it during the next weekend and will come back with results soon.

Hi Ro808,
Quote:

Christoff, if it's not too much of a hassle, it would be interesting to see the effect of a small area of "low curvature" (or even flat) in a (rather deep) waveguide for a hemispherical dome tweeter.
Some space of 2-4mm around the surround "to breath" > might eliminate/cancel interferences.
I'm not sure if I get your idea. Could you possibly give a rough drawing of the profile you are suggesting with rough dimensions? This will help for a simulation.

Christoph

augerpro 21st February 2018 01:25 AM

4 Attachment(s)
Here are the results for SB26ADC on the 8" waveguide. Note, I usually measure with and without phase shield, sometimes with a shim between mouth and tweeter, and sometimes check vertical responses on more promising/new designs. All of this is noted in the screenshot.

augerpro 21st February 2018 01:29 AM

2 Attachment(s)
Much awaited results on the Transducer Lab N26CA! Probably the best of the bunch on the troublesome 5" waveguide. I think the squiggle around 10khz is a similar to issues I had with the SB26, might just need a small lip and/or some tape on the mounting face to stop vibration. Wish these weren't NLA, moving up in size will probably make some beautiful plots.

augerpro 21st February 2018 01:33 AM

8 Attachment(s)
Here is the TW29RN on both 5" and 8" waveguides. With pinned center it's no surprise the phase shield does nothing. The top octave has me miserable. The difference version A and B is slightly different wall radius.

augerpro 21st February 2018 02:06 AM

1 Attachment(s)
For anyone unfamiliar with the natural response of a horn loaded driver, here is the N26 after some simple filtering to flatten the "tilt":

augerpro 21st February 2018 02:42 AM

3 Attachment(s)
Roland, Christoph> here some pics to show what I'd like to focus on (other than the ever present top octave dip in the on axis response so common in waveguides):

Attachment 673037

Attachment 673038

A couple posts back I mentioned the flawed phase shield. The support rod was off-center, and so the response was different when going off axis to one side or the other. Here are the plots going the opposite direction of F above, I *assume* the response with the fixed phase shield should be the average, if so, it should look real good:

Attachment 673039

BTW you can also see the ripple below about 4khz flip flop, so all that ripple is just the baffle diffraction.

Ro808 26th February 2018 01:35 AM

Brendon, apart from the issues >10kHz these look promising, especially the elliptical.

Could you post some pics of these last 2 waveguides with the SB26ADC mounted?
Just to check the throath area: the distance of the surround towards the walls, the height of the dome vs the surround vs. the waveguide.

fatmarley 26th February 2018 06:58 AM

Quote:

Originally Posted by Ro808 (https://www.diyaudio.com/forums/multi-way/318190-source-waveguides-cnc-3d-printing-post5347809.html#post5347809)
Christoff, if it's not too much of a hassle, it would be interesting to see the effect of a small area of "low curvature" (or even flat) in a (rather deep) waveguide for a hemispherical dome tweeter.

Can't remember why, but when I was experimenting with waveguides I thought a bigger gap would solve the top octave issue too.

augerpro 27th February 2018 12:50 AM

1 Attachment(s)
Roland> if I understand you, here is a closeup so you can see how much is outside the surround (about a 1mm):

Attachment 673040

It's tough to get a good pic of these, the nylon is always over-exposed

Pallas 17th March 2018 07:44 PM

1 Attachment(s)
I notice all your WG's are fully rounded. Have you noticed that Revel's waveguide for the SB26 aluminum tweeter has a vertical crease of sorts?

Attachment 673041

I don't know how much harder that would be to model, but wanted to throw it out there.


All times are GMT. The time now is 01:48 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

Wiki