project: Emperor L26ROY (tweeter + Yamaha JA-0801 + Seas L26ROY)

This is a new thread started from a rando post here:

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:
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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

ja0801_sqBaff_1m_GD.png ja0801_triBaff_1m_GD.png
ja0801_sqBaff_1m_decay.png ja0801_triBaff_1m_decay.png

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?
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.
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:


Nothing is perfect so I thought I'd just cram 3 sides into the room ratio and chiral aperiodic shapes.

room_ratio.png chiral_aperiodic_tile.png

I did an ok job trying to freehand it with some gridlines.
img_ja0801_room_ratio.png img_ja0801_chiral_aperiodic.png

Measurements are next up. The baffle is not mounted flush so that mess will be in all of the measurements.

ja-0801_ Diffraction_comp2.png
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.

ja0801 1m_baffle_VS_SPL.png
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.

ja0801 1m_square_decay.png ja0801 1m_tri_decay.png ja0801 1m_roomRatio_decay.png ja0801 1m_aperiodic_decay.png
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.

ja0801 1m_square_rt60.png ja0801 1m_tri_rt60.png ja0801 1m_roomRatio_rt60.png ja0801 1m_aperiodic_rt60.png

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:

ja0801 1m_square_water.png ja0801 1m_tri_water.png ja0801 1m_roomRatio_water.png ja0801 1m_aperiodic_water.png

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:

I took another look at the measurements on-axis at 1m:
ja0801_sqBaff_1m_wat2.png ja0801_triBaff_1m_wat2.png ja0801 1m_roomRatio_wat2.png ja0801 1m_aperiodic_wat2.png
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.


  • outlines_spectre.svg
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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.


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.

ja-0801_aperiodic_3 Diffraction_edge+vs_low.png
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.


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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.

ja0801_baffleVS_rnd2_AP_dist.png ja0801_baffleVS_rnd2_AP2_dist.png ja0801_baffleVS_rnd2_RR_dist.png ja0801_baffleVS_rnd2_RR2_dist.png

Aperiodic 1&2 vs room ration 1&2 distortion. The noise floor does change a bit between the measurements.

ja0801_baffleVS_rnd2_AP2_GD.png ja0801_baffleVS_rnd2_RR2_GD.png ja0801_baffleVS_rnd2_SQ2_GD.png

4ms gate GD of the aperiodic vs room ratio vs square

ja0801_baffleVS_rnd2_AP_wat.png ja0801_baffleVS_rnd2_AP2_wat.png ja0801_baffleVS_rnd2_RR_wat.png ja0801_baffleVS_rnd2_RR2_wat.png ja0801_baffleVS_rnd2_SQ_wat.png ja0801_baffleVS_rnd2_SQ2_wat.png

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.