That is indeed a surprising result
, did you calculate other settings in Akabak as well?
From what its showing me even at 10% open there is just over a 3dB drop, it does start messing with the frequency response under 40% open or less. I've been thinking about it and thought its like having a sliding glass door between you and a noise outside, closed you can somewhat hear it but you don't have to open the door more than a crack to hear it well. I think its safe to use whatever grill material you want to use as long as it isn't solid plate steel
Hi TundraLTD,
Would you share your AkAbak file? I looks like you have the details well worked out.
Regards,
Would you share your AkAbak file? I looks like you have the details well worked out.
Regards,
Sure, I'm cleaning it up right now and adding in some notes. I'll post it later this evening
I've cleaned it up the best I can for now. If you have any questions I will try to answer them. Akabak is extremely complex and I have only been able to get this far thanks to the help of Soho54 and his 
Akabak for Dummies thread @AVS forum.
Have fun!
Akabak for Dummies thread @AVS forum.Have fun!
Hi TundraLTD,
Thanks for the AkAbak file. I'll attach an AkAbak file from geitmans thread: http://www.diyaudio.com/forums/subw...ped-horn-th-spud.html?perpage=25&pagenumber=1. You might find his use of viscosity interesting, maybe a grill could be modelled that way too?
Regards,
Thanks for the AkAbak file. I'll attach an AkAbak file from geitmans thread: http://www.diyaudio.com/forums/subw...ped-horn-th-spud.html?perpage=25&pagenumber=1. You might find his use of viscosity interesting, maybe a grill could be modelled that way too?
Regards,
I'm sure it could but I don't know it in depth enough to get there yet. If anyone else does and would care to explain it that would be cool. I'll rework it tomorrow like that example and see if anything changes
Here it is again this time based on how geitmans built the spud script.
I have no idea what to do with the viscosity numbers at this point. I just used the same numbers for the equivalent area of the horn, if anyone wishes to shed some light on it that would be nice
I have no idea what to do with the viscosity numbers at this point. I just used the same numbers for the equivalent area of the horn, if anyone wishes to shed some light on it that would be nice
Here Ya go. 185V to hit 31mm (8500+ watts) well beyond its warranty rating, 115V for 19mm (3300w)
An externally hosted image should be here but it was not working when we last tested it.
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Post #230
Hi TundraLTD,
Geitmans use the viscosity entry to reflect lining (damping) used in his version of the SPUD. If I remember it right he readjusted the lining a number of times, and then adjusted the viscosity number to bring the simulation results in line with the measured results. Just thought you might find the method he use interesting.
http://www.diyaudio.com/forums/subwoofers/134369-dual-8-tapped-horn-th-spud-5.html
Post #47 - lining example
Post #61 - script
Regards,
Hi TundraLTD,
Geitmans use the viscosity entry to reflect lining (damping) used in his version of the SPUD. If I remember it right he readjusted the lining a number of times, and then adjusted the viscosity number to bring the simulation results in line with the measured results. Just thought you might find the method he use interesting.
http://www.diyaudio.com/forums/subwoofers/134369-dual-8-tapped-horn-th-spud-5.html
Post #47 - lining example
Post #61 - script
Regards,
I've been busy with work and other stuff, so I haven't had any time to finish these!
Here is a quick pic with the second side being fitted...
I cut some handles in the back which really helps for tilting this back and rolling it around (i also fitted it with 210 lb casters...held on by (4) 1/4" bolts, double nuts to stop them from coming loose, and washers of course to help them from pulling through...if there is a problem i can make a backing plate for them out of steel)
And here was a quick test i did just setting the stuff up between fixing two cars for my friend....it makes the ss15 look small and puny! aww! lol
Still need to cut the main brace for the second cab, then work on the cross bracing (mouth bracing) for both cabinets. And the grill as well!
And of course i have to flush trim all the edges, sand, and paint to protect the wood somewhat!
Here is a quick pic with the second side being fitted...
I cut some handles in the back which really helps for tilting this back and rolling it around (i also fitted it with 210 lb casters...held on by (4) 1/4" bolts, double nuts to stop them from coming loose, and washers of course to help them from pulling through...if there is a problem i can make a backing plate for them out of steel)
And here was a quick test i did just setting the stuff up between fixing two cars for my friend....it makes the ss15 look small and puny! aww! lol
Still need to cut the main brace for the second cab, then work on the cross bracing (mouth bracing) for both cabinets. And the grill as well!
And of course i have to flush trim all the edges, sand, and paint to protect the wood somewhat!
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Well I just grabbed these because I honestly didn't think I could do better price wise DIY. I got the xti 2000, and the pair of JBL's with wires for 600...everything was in brand new condition!
I would love to do an active setup in the future if I have enough amp power....
I would love to do an active setup in the future if I have enough amp power....
Very nice deal indeed! But what you build is.... well... you will soon hear them yourself 😀 and we demand a full report!
I don't have anything to measure!
Initial testing without setting up ANY filters on the xti amps and i liked what i heard. i didn't blast it and i had the gains down, so we'll see once i have the right filters in place and group delay (i might need some help with that) etc etc! thanks btw!
Initial testing without setting up ANY filters on the xti amps and i liked what i heard. i didn't blast it and i had the gains down, so we'll see once i have the right filters in place and group delay (i might need some help with that) etc etc! thanks btw!
Cross at 70-80Hz with 5,8 mS for the tops or
120Hz with 10,8mS for the tops.
(165Hz-175Hz with 4,8mS for the tops is also possible)
Tundra calculated a setting for low-cut in post # 189: 24dB Highpass @ 28Hz
120Hz with 10,8mS for the tops.
(165Hz-175Hz with 4,8mS for the tops is also possible)
Tundra calculated a setting for low-cut in post # 189: 24dB Highpass @ 28Hz
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What keeps bothering me about thi sdesign, and I'd love it if someone can set my mind at ease... But, isn't the driver in the path of the presure wave of previous cycles? I.e. lets say a "positive" presure part of a wave arrives at the driver at the same time the cone is trying to move towards the magnet side, or the opposite scenario.
Also because of the time it took the wave to actualy reach the speaker, it is not the wave the speaker is busy produceing at that point (that's a guess, I'll be honest). If this is true, then there should be a time smear or modulation?
Please help me, I'll get no sleep now.
Also because of the time it took the wave to actualy reach the speaker, it is not the wave the speaker is busy produceing at that point (that's a guess, I'll be honest). If this is true, then there should be a time smear or modulation?
Please help me, I'll get no sleep now.