What's the outside dimention of th 4" waveguide for SB26ADC? 4"wide i assume, but how high?
Could it be placed in the cutout of the normal faceplate? Anyone who could give some tips on how to do that? 🤔
Could it be placed in the cutout of the normal faceplate? Anyone who could give some tips on how to do that? 🤔
No it won't fit in standard faceplate cutout. If you open the file in a viewer you can check dimensions. Once I get the routing template finalized, I'll update the files and post general measurements so people have a quick reference.
No. I doubled my college classes, and with a full time career to boot, I've spent every free hour doing homework. I know I sound like a broken record, but I'm trying to get some testing done next week.
Attachments
No problem Brandon, your future is by far more important ! Wish you the best
Jean Claude
Thanks for the information.
A routing template will be a big help. 👍
I saw that there are no screw holes for the driver. What is the best way to attach them to the waveguide?
How/where did you find these dimensions? I go to a 3D webshop and they ask minimum 1 dimension to scale it the proper size. Are those stl-files dimensionless? 🤔
I think .stl is dimensionless. When I update the files I'll be moving to .3mf which include dimensions. FYI unit is inches
There are images earlier on showing a bar across the back of the tweeter with self tapping bolts going into the waveguide body.
I opened the step file and measured them. STL files don't implicitly specify the units so you need to know if the numbers in them refer to mm, inches, metres or miles, that is why they want to know the size it should be.
yes they are dimensionless. I took the measurement from the step file.👍
I noticed that for the SB26ADC 4"waveguide the level is -10db @ 60degrees @10K with the waveguide Without one the level is only 5db down (spec sheet). Isnt the purpose of a waveguide to make the driver broader iso narrower? 🤔
A waveguide will reduce distortion too and bring the accoustic centers inline.
Trying to learn and understand things.
The waveguide purpose is to create a more uniform off-axis response. A bare dome tweeter not have this feature, because the polar response (without waveguide) down low and in the middle is very wide (too wide to match for a midrange driver), then suddenly start narrowing.
its not totally clear to me what you exactly mean.
this is the spec response.
This with waveguide.
I trust more in 3rd party measurements, especially in case of SB Acoustics drivers. Below on the link, we can see the bare SB26ADC measurements that shows exactly -10dB at 60 degree 10kHz:
https://hificompass.com/ru/speakers/measurements/sbacoustics/sb-acoustics-sb26adc-c000-4
Edit: otherwise yeah, the 4" waveguide have very minimal effect on the response of the tweeter, but the effect is not zero.
https://hificompass.com/ru/speakers/measurements/sbacoustics/sb-acoustics-sb26adc-c000-4
Edit: otherwise yeah, the 4" waveguide have very minimal effect on the response of the tweeter, but the effect is not zero.
Last edited:
Thanks. 👍
Troels tested it too and match the spec sheet better.
http://www.troelsgravesen.dk/SBA-tweeters.htm
Maybe some variation on different production runs?
So what you win with the waveguide on a SB26ADC? lower distortion and accoustic alignment? 🤔 maybe more narrower?
What you win with the wg? Better time alignment, more acoustical efficiency, lower distortion, more uniform off-axis, better polar match to a midrange driver, lesser (and better) interaction with the room.
The 4" wg for the SB26 does -3dB at 60 degree 3kHz, whereas the bare tweeter is 0dB, you can't find a midrange driver that does 0dB at 60 degree 3kHz.
Edit: I don't trust the off-axis measurements of Troels Gravesen, his charts usually looks too good (wider than reality) to be true, IMO.
The 4" wg for the SB26 does -3dB at 60 degree 3kHz, whereas the bare tweeter is 0dB, you can't find a midrange driver that does 0dB at 60 degree 3kHz.
Edit: I don't trust the off-axis measurements of Troels Gravesen, his charts usually looks too good (wider than reality) to be true, IMO.
Last edited:
OK make sense. I suppose matching with a bigger driver will be more difficult then with a smaller one. I guess a small 4 inch will be flat @ 2kHz
If the bare tweeter is 0dB @3KHz and the wg one -3dB then Troels measurement may be right and the wg brings the -5db level down to -10db @ 10KHz.
Last edited: