Thanks, now you just need to tell me how to keep the size of waveguide down but still keep it super smoothI told you
Very nice work!
To answer that question I would have to driver the woofer with an Le script which will be the next step. I think it would be better to revert back to actual size now the principal has been validated. Now I have the 15FH500 drivers in stock I can measure the cone, cap and surround to get a better model.
I suspect you can cover it a small amount but it is likely to be the same sort of trade as cutting the woofer into the guide. If I go too low the meshes will intersect meaning I would have to do a lot more CAD work.
The wavelengths radiated by the woofer are much larger compared to the waveguide so I expect much less of an issue. The effect may be comparable around the crossover frequency but that is (should be) quite low in frequency anyway.
So this is at XO... it will also mean that the wavelengths is also much larger than the WG which means its not a WG any longer... as they are the same size...
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It doesn't matter now so much as later when you try to predict the in-room response of the two drivers plus crossover.
I misspoke before. I can add an infinite baffle for a floor/ceiling or both but that enforces a Neumann boundary condition with no damping.
ABEC /AKABAK can simulate rooms with wall damping but that is different than enforcing an infinite baffle, so the two things are separate.
This is the shoebox room with damping example from the ABEC demos. The red dots are pressure boxes, which approximate point sources. The box represents the room boundaries through node points and whatever damping is desired can be added to the walls.
ABEC /AKABAK can simulate rooms with wall damping but that is different than enforcing an infinite baffle, so the two things are separate.
This is the shoebox room with damping example from the ABEC demos. The red dots are pressure boxes, which approximate point sources. The box represents the room boundaries through node points and whatever damping is desired can be added to the walls.
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Here is the woofer box example I used earlier with an infinite baffle placed as the floor under the speaker. The output is measured from the on axis of the speaker not the listening position so that has to be taken into account.
The horizontal doesn't suffer too much
You can see the nulls form in the vertical polar from the floor reflection.
The vertical SPL shows why I don't think it is helpful at this stage, it just becomes hard to see the wood for the trees
The horizontal doesn't suffer too much
You can see the nulls form in the vertical polar from the floor reflection.
The vertical SPL shows why I don't think it is helpful at this stage, it just becomes hard to see the wood for the trees
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Whenever room boundaries are simulated through BEM or like is done in Vituix or Jeff Bagby's spreadsheet, more sources and more reflections smooth out the combined response. A single driver with a single reflection is the worst possible combination to look at.
DonVK has a good example here of using a vertical line of woofers to mitigate the floor bounce.
Modular active 3 way - work in progress
The observation fields show what happens
DonVK has a good example here of using a vertical line of woofers to mitigate the floor bounce.
Modular active 3 way - work in progress
The observation fields show what happens
I already have a speaker that has no appreciable floor and ceiling issues With this speaker build I want to hear what a good 2 way waveguided speaker sounds like. There will be floor and ceiling interaction and that is half the point. Another consideration is the effect of a big dynamic woofer and high sensitivity.
I want to build versions of what I consider to be the best approaches to speaker design from a theoretical standpoint so I know what works best for me. I did dipoles, they are out for full range use. In the bass I could be persuaded to try them again, it would be easy enough to build a trial baffle.
With this speaker build I want to hear what a good 2 way waveguided speaker sounds like. There will be floor and ceiling interaction and that is half the point. Another consideration is the effect of a big dynamic woofer and high sensitivity. I want to build versions of what I consider to be the best approaches to speaker design from a theoretical standpoint so I know what works best for me. I did dipoles, they are out for full range use. In the bass I could be persuaded to try them again, it would be easy enough to build a trial baffle.
You can create a flat panel and give it damping properties if you want to see the bounce effect. It can be a coarse mesh so it has less effect on solve time. It probably will have little effect at reducing the bounce at low freq. (<500Hz) but you can compare the sim to actuals (I did it with a carpet). The quad woofers was better at solving this.
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Thanks Don that's another simple option to try, what damping value did you choose?
Just had a rush of blood to the head and ordered 8 x Sica 5 1,5 CP 16 ohm drivers
5 F 1,5 CP
Models really nicely even in a 1 litre enclosure
Just had a rush of blood to the head and ordered 8 x Sica 5 1,5 CP 16 ohm drivers
5 F 1,5 CP
Models really nicely even in a 1 litre enclosure
Attachments
Impulsive
I was originally planning to use 16R drivers but I could not find a reasonably priced small 16R woofer that goes low in a small volume. I would have preferred 4P config rather than 2S+2P. I did find some SilverFlutes except the shipping was excessive (more than the drivers). The 4P config would have given me higher sensitivity and a closer match to the horn solution as your sim shows.
If you want to put exterior objects (plane carpet , block couch, sphere heads) around the speaker you can use the built in geometry generator ("shell"). Or you can create them in CAD.
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I was originally planning to use 16R drivers but I could not find a reasonably priced small 16R woofer that goes low in a small volume. I would have preferred 4P config rather than 2S+2P. I did find some SilverFlutes except the shipping was excessive (more than the drivers). The 4P config would have given me higher sensitivity and a closer match to the horn solution as your sim shows.
If you want to put exterior objects (plane carpet , block couch, sphere heads) around the speaker you can use the built in geometry generator ("shell"). Or you can create them in CAD.
Code:
Shell "Floor"
SubDomain=1
RefNodes="n"
ShellType=rectangle
Meshing=Delaunay
wD=200cm; hD=200cm;
position=1001,1002,1003
color=Green 0.7
Rotate=0,0,0
Shift=0cm,0cm,0cm
WallImpedance
RefElements="Floor"
ImpType=Reflection
Value=0.5
ft=500HzImpulsive
For me it was
They were only 22 Euros each in quantity and they were in stock and looked well built with nice cast frames etc. I can see potential in these for a few applications so I just bought them before I changed my mind.Any chance you can post or email me the observation scripts you used for the 2034 measurement format?
For me it was
Any chance you can post or email me the observation scripts you used for the 2034 measurement format?
At 22 euros that is a good price. Now that you have them you're practically committed to build with them
Here is the ANSI-CETA-2034A info. It's not as elegant as I would like, because it's my first ride on the spinorama and it needs to be more automated. This is the ABEC observation spectrum script needed to generate a polar contour with 10deg steps. You need a script for horizontal and vertical and they have to be in the correct rotation direction (see spec), from your "on axis" location, as shown when "spectrum hints = on".
Code:
BE_Spectrum // horzontal polar contour plot
PlotType=Polar
GraphHeader="Horizontal Polar"
BodeType=LeveldB
Range_Min=50dB; Range_Max=100dB;
PolarRange=0,360,36
RefNodes="Spectrum"
BasePlane=2001 2002 2003
Distance=200cm
201 Inclination=0.0 ID=2001The attached VACS project has all the processing in the following order. After running spectrum analysis and VACS opens, you need to "convert contour to curves" to get 36 curves for each contour. They will be auto labeled C1->C36 where C1=10deg and C36=360deg (same as 0 deg). Then you need to select all the vertical curves and add them to the horizontal curve graph to get all 72 curves into the same graph. Copy this 72 curve graph several times because you will be performing "n->1" processing on each copy to generate each ceta-2034 curve. You can copy/paste the formulas from the VACS example below. Ensure you select the correct processing "calc mode" and "level type" in the processing pop up window and then paste in the appropriate formula. The final report is just a copy the processed curves to another single graph and maybe adjust the scales. The final report has all level based curves pasted to left Y axis and all DI based curves pasted to right Y axis.
Seems like work, but after you do one, its all copy&paste and the whole curve set takes a couple of minutes to get the final report. I will gratuitously link the thread to where I'm working because the pics are there and I'll attempt to make the process easier in VACS. Modular active 3 way - work in progress
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Shhh don't tell tmuikkuAt 22 euros that is a good price. Now that you have them you're practically committed to build with them
The price and availability was too good to pass up.Thanks I will see if I can work through it, I can get the same view from bmc0's script and Vituix but doing it through VACS interests me too.
