OK, I'll do.
In fact your thread was one of my most important sources during evaluation how-to build an 'Acoustic Lens'. Thanks a lot for sharing.
Gaga
No problem!
The fun part with these lenses is you can do some really bizarre stuff, like mate them to a traditional waveguide. I think you could also feed the lens with dual compression drivers, similar to this JBL setup:
See this D2? And see how sound enters from the left and from the right?
Now rotate that 90 degrees and put a SAW lens at the top and at the bottom.
You'd have one waveguide fed by TWO compression drivers. Should be able to raise your on-axis SPL by about 5-6dB. Or lower the cutoff. Pick one.
The fun part with these lenses is you can do some really bizarre stuff, like mate them to a traditional waveguide. I think you could also feed the lens with dual compression drivers, similar to this JBL setup:
See this D2? And see how sound enters from the left and from the right?
Now rotate that 90 degrees and put a SAW lens at the top and at the bottom.
You'd have one waveguide fed by TWO compression drivers. Should be able to raise your on-axis SPL by about 5-6dB. Or lower the cutoff. Pick one.
Acoustic Lens with 3/4 '' tweeter
Hi 454Casull,
As I did not manage to take new measurements due to very limited time, I add some measurements of the printed acoustic lens using a SB19ST (19mm) tweeter and some information on the construction of the acoustic lens model.
The acoustic lens is based on the information available from the respective patent. See as well the thread by Patrick mentioned above.
3D-constuction:
I did quite some ABEC simulation work during construction of several variants:
Simulation of SPL at 55cm distance by ABEC:
Simulation of horizontal directivity by ABEC:
Situation of horizontal directivity, normalized to 0°:
Measurement of horizontal directivity using SB19ST tweeter (19mm dia), mic distance 55cm:
Comparison of horizontal directivity (SB19ST) normalized to 0°:
Measurement (upper half of image)
ABEC simulation (lower half of image)
Please note that the model simulation in ABEC was slightly different from the final printout - thus the observed differences between simulation and measurement. However, ABEC was still extremely helpful to understand some basic principles of how the acoustic lens worked.
I will probably construct an improved version based on the experiences with this model. More information probably in a German hifi-forum then...
Gaga
PS: For details on construction with ABEC see how-to ABEC thread here.
Hi 454Casull,
As I did not manage to take new measurements due to very limited time, I add some measurements of the printed acoustic lens using a SB19ST (19mm) tweeter and some information on the construction of the acoustic lens model.
The acoustic lens is based on the information available from the respective patent. See as well the thread by Patrick mentioned above.
3D-constuction:
I did quite some ABEC simulation work during construction of several variants:
Simulation of SPL at 55cm distance by ABEC:
Simulation of horizontal directivity by ABEC:
Situation of horizontal directivity, normalized to 0°:
Measurement of horizontal directivity using SB19ST tweeter (19mm dia), mic distance 55cm:
Comparison of horizontal directivity (SB19ST) normalized to 0°:
Measurement (upper half of image)
ABEC simulation (lower half of image)
Please note that the model simulation in ABEC was slightly different from the final printout - thus the observed differences between simulation and measurement. However, ABEC was still extremely helpful to understand some basic principles of how the acoustic lens worked.
I will probably construct an improved version based on the experiences with this model. More information probably in a German hifi-forum then...
Gaga
PS: For details on construction with ABEC see how-to ABEC thread here.
Attachments
-
Acoustic Lens V9c druck fin v3 v4 for ABEC v2 v2 ellypse 2.png -
2017-07-15 AcouLens ABEC wo sym 1.jpg -
2017-07-15 AcouLens V9c ABEC SPL 1m 1.png -
2017-07-15 AcouLens V9c ABEC Sono horiz 6-36dB 3.png -
2017-05-15 ABEC Simu AcouLens SB19 1m Directivity Sono horiz norm0 3-27dB 4.png -
2017-05-15 AcouLens SB19 Mic55cm Directivity Sono horiz 1k-16k 2.png -
2017-05-15 AcouLens SB19 Mic55cm Directivity Sono horiz 1k-16k norm0 vs ABEC Simu 1.png
How are you creating your ABEC mesh?
Are you doing it in a 3D program and then importing it into ABEC?
And if so, which one?
Are you doing it in a 3D program and then importing it into ABEC?
And if so, which one?
Very cool.
It looks like I could output a STL file from 123D, and import it into Gmsh:
[Gmsh] Imported stl mesh size control
That would allow me to do my designs in 123D, where I'm very fast, and simulate them in ABEC
It looks like I could output a STL file from 123D, and import it into Gmsh:
[Gmsh] Imported stl mesh size control
That would allow me to do my designs in 123D, where I'm very fast, and simulate them in ABEC
Hi Christoph 🙂
Very cool simus and mesaurements.
The normalized simus are scaled from +3 to -27dB whereas the measurements are scaled from +0 to -30dB. Did you matched the scales in the comparison graph? For me it seems not, so maybe then it looks even better.
Grüße
Andreas
Very cool simus and mesaurements.
The normalized simus are scaled from +3 to -27dB whereas the measurements are scaled from +0 to -30dB. Did you matched the scales in the comparison graph? For me it seems not, so maybe then it looks even better.
Grüße
Andreas
Hi freddi,
Frankly, I do not know. Could be probably simulated using ABEC. Closest things I worked on was the simulation of diffraction slots using Akabak (see here, watch out, German...).
Hi Andreas,
You are right, I did not correctly align scales of measurements and simulations.
There are more shortcomings with the simulation:
- Have to check distance of simulation vs measurement;
- The printed lens slightly differs from the simulated lens (rounded edges);
- The SB19 was not simulated as a dome, but as a flat disc;
- Have to check the TSP I used to simulate the SB19;
I'll go back to the simulation, check things and re-do the simu...😉
Grüße,
Christoph
Frankly, I do not know. Could be probably simulated using ABEC. Closest things I worked on was the simulation of diffraction slots using Akabak (see here, watch out, German...).
Hi Andreas,
Thanks a lot! 🙂
You are right, I did not correctly align scales of measurements and simulations.
There are more shortcomings with the simulation:
- Have to check distance of simulation vs measurement;
- The printed lens slightly differs from the simulated lens (rounded edges);
- The SB19 was not simulated as a dome, but as a flat disc;
- Have to check the TSP I used to simulate the SB19;
I'll go back to the simulation, check things and re-do the simu...😉
Grüße,
Christoph
Hi,
Just FYI - if someone might be interested: I'm trying to show a step-by-step construction, print-out, measurement of the 'Acoustic Lens' in a German DYI-HiFi-Forum here. I hope it's ok to point to a thread in another forum.
However, please indicate, if you might be interested in a specific piece of information given there, I'd try to translate and present it here then accordingly...
Gaga
Just FYI - if someone might be interested: I'm trying to show a step-by-step construction, print-out, measurement of the 'Acoustic Lens' in a German DYI-HiFi-Forum here. I hope it's ok to point to a thread in another forum.
However, please indicate, if you might be interested in a specific piece of information given there, I'd try to translate and present it here then accordingly...
Gaga
Anyone able to help me on the Sketchup software. The component I have on the right is the 2D lens im trying to rotate but doing so causes one side to be empty, how do I make it solid.
An externally hosted image should be here but it was not working when we last tested it.
Last edited:
I increased the number of segments on the circular paths to 360.
edit, i think when I made the arc segment I didnt change the number of segments. it must be having trouble lining up.
Still showing up as hollow
The Hat was able to be created fine
edit, i think when I made the arc segment I didnt change the number of segments. it must be having trouble lining up.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Still showing up as hollow
The Hat was able to be created fine
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Last edited:
Figured it out, when you use the follow-me tool the circle you ride must be smaller or bigger than your revolution path, otherwise it does the opposite.
An externally hosted image should be here but it was not working when we last tested it.
I have never used either software. But I will attempt to learn it. I did a search and found your thread tutorials. You make it sound easy.
Danke!
Hi Megalomaniac,
Just indicate, if you need translations of the ABEC thread. Or may be post the *.step or *.stp file of your lens for download if possible. I could try a simulation as well...
Whatsoever, I'd be interested to learn more about your acoustic lens.
BW,
Christoph
Just indicate, if you need translations of the ABEC thread. Or may be post the *.step or *.stp file of your lens for download if possible. I could try a simulation as well...
Whatsoever, I'd be interested to learn more about your acoustic lens.
BW,
Christoph
I have also modeled, 3D printed and now CNC'd a similar acoustic lens, wee below
Build log : DIY Beolab 18
I'll definitely look into the simulation part thanks for pointing that out
Pierre
Build log : DIY Beolab 18
I'll definitely look into the simulation part thanks for pointing that out
Pierre
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