This is a new thread started from a rando post here: https://www.diyaudio.com/community/threads/headshakes-far-field-3way.382393/post-7434715
I've made a 3" ETON + t25b box before and this will be a reworking of the same setup. I like the idea of being able to swap out the HF/MF boxes.
The Seas L26ROY is in a PartsExpress box. It is by chance that it fits without any adjustment.
I will measure the drivers next and make an ideal sim to reference along the way.
The JA-0801 is in a foam baffle for now. I used some Loctite power grab and some wood skewers to hold the stand together. Metal screws are holding the driver down.
The hypex FA123 can be seen at the bottom of the image.
The tweeter will be picked later.
A translated info sheet about the dome:
I've made a 3" ETON + t25b box before and this will be a reworking of the same setup. I like the idea of being able to swap out the HF/MF boxes.
The Seas L26ROY is in a PartsExpress box. It is by chance that it fits without any adjustment.
I will measure the drivers next and make an ideal sim to reference along the way.
The JA-0801 is in a foam baffle for now. I used some Loctite power grab and some wood skewers to hold the stand together. Metal screws are holding the driver down.
The hypex FA123 can be seen at the bottom of the image.
The tweeter will be picked later.
A translated info sheet about the dome:
I have some eq to roll off the ja-0801. No boosts or other eq yet but it looks pretty flat.
The measurements are at 1m but the mic stand slipped so this is slighly lower than on-axis. My darn stand needs to be crazy tight or it slips down after a few min.
I was curious about the baffle size and messing with the decay. VCAD predicted some mess around 2k.
The tri baffle is just some shapes stuck onto the square baffle. The goal was to see if the GD and decay would change.
Square vs Triangular
My very rough estimate of the sd and baffle sim. The tri baffle is the orange line:
My aim is for a very random decay and smooth GD. If the baffle is mostly square 21cm shape then that shows up in the decay:
This is just a repeat of the square baffle with a curser to show the WL of the baffle.
Some better on-axis measurements are next but maybe I want a baffle with a nice random shape but not larger than a 1khz WL?
The measurements are at 1m but the mic stand slipped so this is slighly lower than on-axis. My darn stand needs to be crazy tight or it slips down after a few min.
I was curious about the baffle size and messing with the decay. VCAD predicted some mess around 2k.
The tri baffle is just some shapes stuck onto the square baffle. The goal was to see if the GD and decay would change.
Square vs Triangular
My very rough estimate of the sd and baffle sim. The tri baffle is the orange line:
My aim is for a very random decay and smooth GD. If the baffle is mostly square 21cm shape then that shows up in the decay:
This is just a repeat of the square baffle with a curser to show the WL of the baffle.
Some better on-axis measurements are next but maybe I want a baffle with a nice random shape but not larger than a 1khz WL?
Right, look to room ratios for shapes pg. 242. As for the 1 kHz, not sure of your performance goal, but with 'freehand' shapes an averaged frequency is normally required/desired.
Thanks, @GM . Cool book link. I read the section you pointed to- it seems to be more about LF and rooms. I will read through the whole thing.
I am just messing arround ATM. The baffle is in the response, so my goal is to have a shape that helps and not hurts. I tend to focus more on the baffle shape and do not really think about the room. A rounded and asymmetrical shape is probably more ideal but I like to compare things if it is easy enough.
I am just messing arround ATM. The baffle is in the response, so my goal is to have a shape that helps and not hurts. I tend to focus more on the baffle shape and do not really think about the room. A rounded and asymmetrical shape is probably more ideal but I like to compare things if it is easy enough.
The room ratio plot shape reminds me of:
https://www.smithsonianmag.com/smar...-with-a-pattern-that-never-repeats-180981899/
An non-repeating shape.
I'll give it a go. Thanks again!
https://www.smithsonianmag.com/smar...-with-a-pattern-that-never-repeats-180981899/
An non-repeating shape.
I'll give it a go. Thanks again!
Did some cutting and will compare a square, triangular, room ratio, and chiral aperiodic shapes. It might just work out that the smallest baffle is best but this will be neat to see.
Paper on aperiodic:
https://arxiv.org/abs/2305.17743
Nothing is perfect so I thought I'd just cram 3 sides into the room ratio and chiral aperiodic shapes.
I did an ok job trying to freehand it with some gridlines.
Measurements are next up. The baffle is not mounted flush so that mess will be in all of the measurements.
Baffle sim of the shapes.
Paper on aperiodic:
https://arxiv.org/abs/2305.17743
Nothing is perfect so I thought I'd just cram 3 sides into the room ratio and chiral aperiodic shapes.
I did an ok job trying to freehand it with some gridlines.
Measurements are next up. The baffle is not mounted flush so that mess will be in all of the measurements.
Baffle sim of the shapes.
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Did some measurements of the baffle shapes. It is a small square vs triangular vs room ratio vs aperiodic baffle shapes.
I used some tape on the ja-0801 and measured 1m with a laser distance meter. There were some differences in SPLs so the decay should be taken with a grain of salt.
The decay is a fast gate to show what is right off the baffle. The goal is a random 30ms and 300ms.
I was hoping for a clear runaway winner. The tri baffle does a better 2khz-3khz. The aperiodic does a nice 600hz-1khz. The room ratio has a generally nice even decay across the board.
I think what I am looking for can be seen in the RT60: a nice random change between the EDT (-10db down) and what happens at the other decay times. I was surprised the aperiodic has a faster EDT that most at 700hz-1khz.
more info:https://www.roomeqwizard.com/help/help_en-GB/html/graph_rt60.html
subjective listening observations: I have been listening to music with each baffle with just the ja-0801 playing. With the square baffle, it sounds small and easy to locate. The aperiodic is hard to place the location in the room and sound bigger. This could all be in my head but my decay measurements show the room ratio and aperiodic do have different decays than the square.
I used some tape on the ja-0801 and measured 1m with a laser distance meter. There were some differences in SPLs so the decay should be taken with a grain of salt.
The decay is a fast gate to show what is right off the baffle. The goal is a random 30ms and 300ms.
I was hoping for a clear runaway winner. The tri baffle does a better 2khz-3khz. The aperiodic does a nice 600hz-1khz. The room ratio has a generally nice even decay across the board.
I think what I am looking for can be seen in the RT60: a nice random change between the EDT (-10db down) and what happens at the other decay times. I was surprised the aperiodic has a faster EDT that most at 700hz-1khz.
more info:https://www.roomeqwizard.com/help/help_en-GB/html/graph_rt60.html
subjective listening observations: I have been listening to music with each baffle with just the ja-0801 playing. With the square baffle, it sounds small and easy to locate. The aperiodic is hard to place the location in the room and sound bigger. This could all be in my head but my decay measurements show the room ratio and aperiodic do have different decays than the square.
There is a more complex "Spectre" tile that I am interested in trying out. I made a quick mockup but will need to measure the ja-0801 with some cardboard before going forward with a part. The quick mockup was used to determine if I could even make a laser cut part this large- i can but it won't be cheap.
I just put the tweeter in a random spot. I would like to confirm in vcad the spacing.
more aperiodic tile links:
https://github.com/christianp/aperiodic-monotile
https://cs.uwaterloo.ca/~csk/spectre/
I took another look at the measurements on-axis at 1m:
It seems like a very long decay shows the differences. The decay times are much longer than I thought would matter. I might do another round of measuring just to confirm.
The room ratio curve is also something I am still tracing. The aperiodic shape was ready to go thanks to the github files. I am curious how both perform with a flush mounted driver.
I just put the tweeter in a random spot. I would like to confirm in vcad the spacing.
more aperiodic tile links:
https://github.com/christianp/aperiodic-monotile
https://cs.uwaterloo.ca/~csk/spectre/
I took another look at the measurements on-axis at 1m:
It seems like a very long decay shows the differences. The decay times are much longer than I thought would matter. I might do another round of measuring just to confirm.
The room ratio curve is also something I am still tracing. The aperiodic shape was ready to go thanks to the github files. I am curious how both perform with a flush mounted driver.
I used inkscape to convert the image to a vector. This worked better than me trying to trace the curves myself. It is pretty darn close. (black lines = raster and the red = vector)
The svg is attached.
more: https://inkscape.org/
This past weeked I measured the dimension of the ja-0801 and have that in a newer baffle design. The spacing is for the XO. I still need to do more in vcad to compare the sims. My gut/experience still likes the idea of a tweeter on a stick so this is going against that.
A vcad diffraction sim: This is a comparison of the tweeter being at the top (orange line) vs bottom section (magenta) of the baffle. I was also interested in how the mid would sim at opposite horizontal positionsnso those are tossed in too.
The svg is attached.
more: https://inkscape.org/
This past weeked I measured the dimension of the ja-0801 and have that in a newer baffle design. The spacing is for the XO. I still need to do more in vcad to compare the sims. My gut/experience still likes the idea of a tweeter on a stick so this is going against that.
A vcad diffraction sim: This is a comparison of the tweeter being at the top (orange line) vs bottom section (magenta) of the baffle. I was also interested in how the mid would sim at opposite horizontal positionsnso those are tossed in too.
I did a second round of comparing baffles. I wanted to be sure I was not just looking at the noise floor and did not make a choice from one measurement. So this time I did a second measurement of each baffle to compare and and shaded out everything below -40db in the waterfall.
Only 3 baffles were compared, the Aperiodic (AP), Room ratio (RR), and square (SQ).
SPL's show the measurements are darn close and the different baffles have different spl's on-axis. I really think much of the difference comes from the size and the interaction with the seas woofer's surround - somewhere around 1.8khz it is bouncing back depending on the baffle.
Aperiodic 1&2 vs room ration 1&2 distortion. The noise floor does change a bit between the measurements.
4ms gate GD of the aperiodic vs room ratio vs square
waterfall: Aperiodic 1&2 vs room ratio 1&2 vs square 1&2
The duplicate measurements are very close. It seems like the AP baffle does a nice job with longer frequencies and decays but this could just be because of the size- it is physically taller than the RR. I am now wondering what happens when the AP and RR are roughly the same size. I was hoping for clarity but don't think I have it yet.
Only 3 baffles were compared, the Aperiodic (AP), Room ratio (RR), and square (SQ).
SPL's show the measurements are darn close and the different baffles have different spl's on-axis. I really think much of the difference comes from the size and the interaction with the seas woofer's surround - somewhere around 1.8khz it is bouncing back depending on the baffle.
Aperiodic 1&2 vs room ration 1&2 distortion. The noise floor does change a bit between the measurements.
4ms gate GD of the aperiodic vs room ratio vs square
waterfall: Aperiodic 1&2 vs room ratio 1&2 vs square 1&2
The duplicate measurements are very close. It seems like the AP baffle does a nice job with longer frequencies and decays but this could just be because of the size- it is physically taller than the RR. I am now wondering what happens when the AP and RR are roughly the same size. I was hoping for clarity but don't think I have it yet.