Yeah, and I liked the fact that post 73 had more response at 30Hz. And I also realized (after I posted my request to you guys) that post 73 was flatter to 30Hz than the one I modded. Even tho my modded cab had more output, it jumps 4dB from 30 to 40Hz - where as yours only jumps ~2dB. I really would like flatter to 30Hz with the most output as well. So, sorry for puttin in that request prematurely.
73 remains my fave (size & output at 30Hz - bein flat from 30Hz). Is there an easier way to fold it?
If not, could you send me those details, epa?
Again, many, many thanks to you talented individuals!!
Justin
Reality Check?
Post 73 (Epa) @ 2.83V
30Hz = 95.28 dB
40Hz = 98.58 dB
3.3 dB difference
Post 98 (Xoc1) @ 2.83V
30Hz = 96.17 dB
40Hz = 100.74dB
4.57 dB difference, so step from 30 to 40 Hz is 1.27 dB more...
Post 98 is more efficient at both frequencies as would be expected as it is bigger. External is 600 litres compared to 397 for post 73.
Biggest misgiving I have about the post 73 design is the small S3 dimension.
At 1236 this is about the same size as SD. You can see how tight the mouth is positioned to the rear of the driver. This would require care and adjustment to make it work due to the driver seriously restricting the mouth. I suppose an access panel would be needed to actually get the driver in the box!
Post 73 (Epa) @ 2.83V
30Hz = 95.28 dB
40Hz = 98.58 dB
3.3 dB difference
Post 98 (Xoc1) @ 2.83V
30Hz = 96.17 dB
40Hz = 100.74dB
4.57 dB difference, so step from 30 to 40 Hz is 1.27 dB more...
Post 98 is more efficient at both frequencies as would be expected as it is bigger. External is 600 litres compared to 397 for post 73.
Biggest misgiving I have about the post 73 design is the small S3 dimension.
At 1236 this is about the same size as SD. You can see how tight the mouth is positioned to the rear of the driver. This would require care and adjustment to make it work due to the driver seriously restricting the mouth. I suppose an access panel would be needed to actually get the driver in the box!
restriction is not to bad because of the neodinium magnet.Post 73 (Epa) @ 2.83V
30Hz = 95.28 dB
40Hz = 98.58 dB
3.3 dB difference
Post 98 (Xoc1) @ 2.83V
30Hz = 96.17 dB
40Hz = 100.74dB
4.57 dB difference, so step from 30 to 40 Hz is 1.27 dB more...
Post 98 is more efficient at both frequencies as would be expected as it is bigger. External is 600 litres compared to 397 for post 73.
Biggest misgiving I have about the post 73 design is the small S3 dimension.
At 1236 this is about the same size as SD. You can see how tight the mouth is positioned to the rear of the driver. This would require care and adjustment to make it work due to the driver seriously restricting the mouth. I suppose an access panel would be needed to actually get the driver in the box!
restriction is not to bad because of the neodinium magnet.
You could design it so that the entire front panel (or a major part of it) is removeable. Not only will that give you full access to the driver, it will also allow you to play around with the mouth's geometry without having to hack away at any fixed panels.
i designed the post 73 th for the use in a cardroid sub aray.
this is why its symetric.
i like xco1 model 2,its a easier bild but for me a little to big.
i wil work this weekend on it to give you al the details
meanwile here are some designs,most of them are posted here.to make your choice more diffecult
@justin
what material do you want to use ,i srongly sugest birch plywood,but i cant look in your wallet
do you want to make it 12 or 15mm .
i need 2 now before i start working on it
Yeah, I use birch. At least 15mm. You don't think 12mm will have too much flex, even w/bracing? I'd rather be safer than sorry. Thanks a ton (again).
Justin
ok lets make it 15mm.i think 18 is a bit over the top.
horizontal there are only small spaces ,and vertical wil do some bracing in the middle.
front wil be removeble in one piece.
it might be a good idee to send you the dwg,dxf file when im finnished.
then you can make a 1 on 1 print on A0 paper(it fits)in the copy store.
cost about 4 euro here on this side of the pond
horizontal there are only small spaces ,and vertical wil do some bracing in the middle.
front wil be removeble in one piece.
it might be a good idee to send you the dwg,dxf file when im finnished.
then you can make a 1 on 1 print on A0 paper(it fits)in the copy store.
cost about 4 euro here on this side of the pond
justin ,we need to make a new topic,because this has no longer anything to do with woodys design ,
http://www.diyaudio.com/forums/subw...at-30-ft30-pa-th-awesomeness.html#post2379198
I'm a little late to the game, but wanted to post my 2 cents: with a typical high-DF amp, you will NOT be putting in extra power for the same SPL as power compression kicks in. The impedance rises... unless you mean that the volume is cranked up after the fact, in which case the volume should be set and then locked.Everyone just forgets to factor in power compression, and other things that come into effect at the ends of a drivers throw.
Once you get to ~500w with a majority of drivers, it is not unheard of to be 2-4dB down already, so it is easy to see how you can throw 2-3x the power expected into an enclosure, and not have it grenade on you from over excursion. Assuming a HP is in place of course.
The best way to get around this is to not count on having the last 3-6dB of sim output. If you need 130dB at 1m, you need the speakers to sim around 133-136dB.
Also, IIRC, musical transients are little-affected by power compression.
I'm afraid, you don't remember it correctly because there is nothing wrong with Soho's statement you quoted. Besides "volume" is not referring to any kind of electric variable/value, it actually doesn't matter much how cheap your amplifier is as long it can deliver the power necessary to drive the driver into power/dynamic compression.
The relation is power versus electrical/physical properties of the driver. Also transients (and even response) are very much affected when a driver 'suffers' from severe power/dynamic compression. 'Suffer' with two accents because PA driver are often designed to have better response at 2/3dB power/dynamic compression.
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my project loaded with an 18inch driver
Attachments
also please do tell me is xocs1 design better than this in terms of spl and flat in response.
here you go have fun
Hi Stewin
I have not found the time yet to work out the path length of your TH fold.
I have CAD of similar folds so will adapt one to your dimensions.
I would need to know more about the drivers you have to be able to run a sim.
You said in the TH18 thread that you have the 'new retone nr 18 speaker' but I cant seem to find any details on this driver on line.
As for the throat restriction you have used, that adds a lot more unknowns that might only be answered with practical testing.
The 35Hz hi pass filter you have sounds perfectly reasonable but to check it in Hornresp you will need all the driver parameters.
The Xoc1TH18 with the throat correction might be louder at the expense of not being lower but it all depends on the driver.
Regards Xoc1
I have not found the time yet to work out the path length of your TH fold.
I have CAD of similar folds so will adapt one to your dimensions.
I would need to know more about the drivers you have to be able to run a sim.
You said in the TH18 thread that you have the 'new retone nr 18 speaker' but I cant seem to find any details on this driver on line.
As for the throat restriction you have used, that adds a lot more unknowns that might only be answered with practical testing.
The 35Hz hi pass filter you have sounds perfectly reasonable but to check it in Hornresp you will need all the driver parameters.
The Xoc1TH18 with the throat correction might be louder at the expense of not being lower but it all depends on the driver.
Regards Xoc1
thanks xoc1 . the speaker is Chinese and there are no specs or booklet in the box
http://translate.google.com/transla...&sa=X&ei=2zC2UZCWOoeoO_H9gYgI&ved=0CGsQ7gEwCA
>>>>also another challenge i got is designing a 24db crossover with 35hz cutoff but it failed because when i connect it the bass is not even close to deep, it seems like it rolls of at around 80hz instead of 35hz. where am i wrong in the crossover?.
http://translate.google.com/transla...&sa=X&ei=2zC2UZCWOoeoO_H9gYgI&ved=0CGsQ7gEwCA
>>>>
also another challenge i got is designing a 24db crossover with 35hz cutoff but it failed because when i connect it the bass is not even close to deep, it seems like it rolls of at around 80hz instead of 35hz. where am i wrong in the crossover?.Attachments
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