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Old 16th August 2012, 05:43 PM   #1
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Default Simulating bass response with duct and speaker position

Which software can accurately predict bass response taking into consideration the duct position on the baffle ( wrt ground) and location of bass driver on the panel and enclosure location from side walls.
Calsod 3.1 ?
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Old 16th August 2012, 09:17 PM   #2
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Good old Akabak should do this, but it is always major PITA to set it up properly ("GUI? We don't need no stinking' GUI"!)
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Old 16th August 2012, 09:47 PM   #3
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Boxsim? I may be mistaken, but i think Boxsim will do what you require. I guess it depends what 'output' data you require. Do you mean to include room influence? Boxsim doesnt do that. I couldnt say for sure if floor bounce is simulated, but port location, depth and height, baffle effect, are all simulated. I havent tried Akabak and i dont know if it is free or commercial.
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Old 17th August 2012, 07:25 AM   #4
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Thanks guys. Yes I wanted floor bounce also included and Boxsim apparently doesn't do that.
I'll check out Akabak.
Wonder if Sy will see this post as he has used Calsod 3.1 and might know if that can do it.

Basically it is to see 'room' performance of bass of a stand alone ducted sub .
I'm guessing that a port placed very close to the ground or even slot loaded and placed very close to the ground might perform differently to a duct that's high up on the baffle or even at it's rear facing the ( near) rear wall.
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Old 17th August 2012, 08:20 AM   #5
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ashok, boxsim does do combined port and driver response, port location etc. Everything you ask for, but there is no specific 'floor bounce' button to press. That doesnt mean it doesnt simulate it, im just wary of saying YES outright, since i cant prove it. People tend to jump on you, if you cant prove with DBTesting. However to include the room influence, boxsim ismt suitable. Im not even sure Akabak does this to be honest, although i could be wrong. Someone pipe up if im wrong, as i would like to measure similarly to Ashok, eventually.
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Old 17th August 2012, 11:33 AM   #6
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mondogenerator and KSTR,
Would it be interesting to check out what the software ( both ) say and what one can get in practice. I have some time and spare drivers. Maybe I can sim one box and see what we get when measured. I'll put up the driver specs soon. I have a Clio V4.52 that I can use for measurements ( with mic01).
I can make the box and alter it ( to move the duct around !) . I have all the tools. Interested ?
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Old 17th August 2012, 12:03 PM   #7
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if you have frd and zma files, it would be quite simple to try in boxsim. I have no idea about akabak. I think its a commercial program, again i could be mistaken, but i would expect if im correct, that akabak may be the more capable program. Im jealous of the clio, im still trying to find an affordable measurement set up!
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Old 17th August 2012, 12:16 PM   #8
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Default a small anecdote

i recently finished my 2way TQWT, and one criticism i got was the 'tower' type enclosure. Since the woofer is 70cm from floor level, i expected a floor bounce dip in the low mids. The boxsim response is within 2dB from 100hz to 15k, but as i mentioned, i cant prove that boxsim accounts for it. Once i had a heavy listening session i couldnt hear a dip. So i did a quick unmeasured sine sweep, and still i dont hear a dip. Its hardly scientific but this test seemed to suggest that the floor bounce dip isnt there, or is not severe. My port is as close to the floor as possible, 4cm. It is front firing. Sub Fb bass rolls out along the floor, and has more 'weight' than i expected. Perhaps locating a port like this helps to negate floor bounce? Just a passing thought, again i couldnt prove, which is why i will measure. One day
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Old 17th August 2012, 02:23 PM   #9
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AkAbak is available at no cost from R&D Team: R&D-Team - Software Development
However, you will need to invest some time in learning to use it.
There are tutorials available, for example:
Akabak Simulator

AkAbak allows specifying the dimensions of the enclosure and the placing of the drivers and ports on the panels. It also allows you to specify up to 3 "reflectors" (selected from ceiling, floor, 2 walls) orthogonal to each other and their orientation and distance from the speaker. Finally, it allows specifying the measurement "microphone" position.
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Old 17th August 2012, 02:49 PM   #10
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Thanks Don!

Im glad to find I was wrong about Akabak being commercial! (I was at work, and posting using mobile phone, so couldnt check for the software)

3 reflector is handy too! Boxsim doesnt do that, now im sure about that!

So I guess you could use rear wall, floor and ceiling? Or would another 3 surfaces be better? The only thing that is missing, for me, is the ability to 'draw' a room.

Some time ago I made some sketch up 3D plans of the rooms in my apartment, since no room has a conventional ceiling. the only cuboid room I have is the entrance hall. L shaped living room, in rafters of the roof. 2 alcoves, 1 which is pretty pointless, and the other housing a window. 45 degree ceiling from about 5'5" upwards to the 8' ceiling height. Is there any software that would model my room?
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