Bad desing keistone sub
bad design , with the trapezoidal output does is correct a curve with a depth of nearly -6db in 60 hz .
with a more appropriate design and less liters you have an answer as well or better . For example the 18 xoc1 , danley 18 th or you want a similar design danley th412
bad design , with the trapezoidal output does is correct a curve with a depth of nearly -6db in 60 hz .
with a more appropriate design and less liters you have an answer as well or better . For example the 18 xoc1 , danley 18 th or you want a similar design danley th412
Tetrapol,
I don't understand what you are writing about "a curve with a depth of nearly -6db in 60 hz", there is no lack of 60 Hz in the Keystone.
PASC built a Keystone and an XOC1 TH18 and reports his findings in posts #114 & 115, they are quite different from your assessment.
The DSL TH-118 (or the identical sized XOC1 TH18) is slightly smaller (less volume) than the Keystone, but the cabinet depth is deeper, 28.5" compared to only 22.5" for the Keystone.
The DSL TH-412 is twice the size (and weight) and half the impedance of the Keystone, hardly a "similar design".
Art
Hello everyone!
How would the RCF L18P300 perform in the Keystone design? Would someone be so kind to simulate this combination and share the results?
I am currently looking for a design to mate with 14 of these woofers, it's going to be a big project. Another option I am considering is an modified version of the Cubo 18 (extended).
Thanks.
How would the RCF L18P300 perform in the Keystone design? Would someone be so kind to simulate this combination and share the results?
I am currently looking for a design to mate with 14 of these woofers, it's going to be a big project. Another option I am considering is an modified version of the Cubo 18 (extended).
Thanks.
Hi Art,
So I've got 2 B&C18SW115 arriving in the next few days and want to start work on the Keystone, I had thought to do 2 TH18's but the Keystone build looks a little easier but similar performance. Looking at the drawings I was thinking that maybe there would be some benefit in increasing the bracing, would recommend this or is it not necessary or no added gain??
Regards,
Rowan
So I've got 2 B&C18SW115 arriving in the next few days and want to start work on the Keystone, I had thought to do 2 TH18's but the Keystone build looks a little easier but similar performance. Looking at the drawings I was thinking that maybe there would be some benefit in increasing the bracing, would recommend this or is it not necessary or no added gain??
Regards,
Rowan
I made it! 57 pages. read every word.
Countless advice from others on another thread and ready to begin.
Before I start questions:
My Drivers = B&C 18TBW100-4
1) PDF in #487 is still the most current version and I can take these dims as law?
2) Wood - Art, you mentioned no point to go to 1" over 3/4" (I read somewhere that DSL "lost something" between their calculated models and their actual build, moving to 1" construction "brought back the difference") I realize they are an actual company and marketing is what it is Tom has to eat. This is just what is bugging me. I am currently searching for 13-ply Baltic Birch in the Los Angeles area, but if I do have to use a lesser wood, I wonder if 1" would matter? If you saw to use 3/4" one more time, I won't bring this up again
3) Does the smoothness of the interior matter? I know in upper frequencies it does. Would extra time to sand the inside smooth be wasted energy?
4) Would their be any benefit at all to making the front panel a single piece of wood instead of 2. Reason being, the brace right at the seem, behind the motor - with a single piece of wood it could be eliminated (this goes back to the "smoothness" transition to the exit
4) I was reading on another thread about your experiments with an extension panel that attaches to the front, that it actually increases LF output - for the EDM style we discussed in the other thread this seems very win - win to me. What are your thoughts on just building the outside panels wider to begin with essentially having it a permanent design?
5) for an outside venue - is the best placement still going to be dead center of the DJ booth sitting side by side the layout is about 10'x 50' long (worse possible dimensions?)
Countless advice from others on another thread and ready to begin.
Before I start questions:
My Drivers = B&C 18TBW100-4
1) PDF in #487 is still the most current version and I can take these dims as law?
2) Wood - Art, you mentioned no point to go to 1" over 3/4" (I read somewhere that DSL "lost something" between their calculated models and their actual build, moving to 1" construction "brought back the difference") I realize they are an actual company and marketing is what it is Tom has to eat. This is just what is bugging me. I am currently searching for 13-ply Baltic Birch in the Los Angeles area, but if I do have to use a lesser wood, I wonder if 1" would matter? If you saw to use 3/4" one more time, I won't bring this up again
3) Does the smoothness of the interior matter? I know in upper frequencies it does. Would extra time to sand the inside smooth be wasted energy?
4) Would their be any benefit at all to making the front panel a single piece of wood instead of 2. Reason being, the brace right at the seem, behind the motor - with a single piece of wood it could be eliminated (this goes back to the "smoothness" transition to the exit
4) I was reading on another thread about your experiments with an extension panel that attaches to the front, that it actually increases LF output - for the EDM style we discussed in the other thread this seems very win - win to me. What are your thoughts on just building the outside panels wider to begin with essentially having it a permanent design?
5) for an outside venue - is the best placement still going to be dead center of the DJ booth sitting side by side the layout is about 10'x 50' long (worse possible dimensions?)
2)I think a more effective way to increase the cabinet stiffness is to use a large number of small braces placed intelligently. Big deflections come from big unfixed resonant areas.
3) Huge waste of time. There's several reasons why (the wavelengths involved are massive and the boundary layer on the surfaces is miniscule compared to the cabinet dimensions) but the gist is don't bother. You have to get way up into tweeter territory before it even makes a bit of difference. Might not be a bad idea to paint the inside of the cabinet for longevity though. Protects from moisture and whatnot.
4a)If I'm interpreting this right, you'll be eliminating the removable front panel. Unless you don't mind having to cut up your cabinet to replace/repair the driver it seems inadvisable. Also, as with the sanding, these frequencies don't "see" anything that small. A 50hz wave, for reference, is 6.8m long. Braces are good.
5)This one can get complicated. The advice of center clustered subs is not unreasonable because it produces maximum SPL, uniform coverage, no interference patterns and no lobing. Simple, good, and works well. Might even be the best choice.
But this is a good example when interference patterns might be exactly what you want. If you've got a long, narrow area you want to cover, the dreaded "power alley" might just be what you're looking for. This also might be a good place for somebody with more practical show experience than me to chime in, but take a look at this. Specifically, look at page 8. It gives you an idea of what I'm talking about.
http://www.geluid-licht.nl/huur/bass%20guide.pdf
Something like the 2m center to center spacing might give good results.
The only caveat is you really have to start thinking about what it's doing to the pattern at different frequencies and where you're running the subs. If you're covering 35-100hz and you've achieved a nice lobe over the dancefloor at 100hz, your 50hz is radiating more uniformly and you might have to boost it to catch up to the higher frequencies on your floor. If this seems a bit too complicated, don't worry about it too much. It's just something to think about.
Also you used number 4 twice. heh
3) Huge waste of time. There's several reasons why (the wavelengths involved are massive and the boundary layer on the surfaces is miniscule compared to the cabinet dimensions) but the gist is don't bother. You have to get way up into tweeter territory before it even makes a bit of difference. Might not be a bad idea to paint the inside of the cabinet for longevity though. Protects from moisture and whatnot.
4a)If I'm interpreting this right, you'll be eliminating the removable front panel. Unless you don't mind having to cut up your cabinet to replace/repair the driver it seems inadvisable. Also, as with the sanding, these frequencies don't "see" anything that small. A 50hz wave, for reference, is 6.8m long. Braces are good.
5)This one can get complicated. The advice of center clustered subs is not unreasonable because it produces maximum SPL, uniform coverage, no interference patterns and no lobing. Simple, good, and works well. Might even be the best choice.
But this is a good example when interference patterns might be exactly what you want. If you've got a long, narrow area you want to cover, the dreaded "power alley" might just be what you're looking for. This also might be a good place for somebody with more practical show experience than me to chime in, but take a look at this. Specifically, look at page 8. It gives you an idea of what I'm talking about.
http://www.geluid-licht.nl/huur/bass%20guide.pdf
Something like the 2m center to center spacing might give good results.
The only caveat is you really have to start thinking about what it's doing to the pattern at different frequencies and where you're running the subs. If you're covering 35-100hz and you've achieved a nice lobe over the dancefloor at 100hz, your 50hz is radiating more uniformly and you might have to boost it to catch up to the higher frequencies on your floor. If this seems a bit too complicated, don't worry about it too much. It's just something to think about.
Also you used number 4 twice. heh
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I see I decided the number 4 was so good it should be used twice. So going forward I will call that 4A and 4B.
Regarding the bracing, just a few posts above I see Art use one of my least favorite words "adequate" in terms of bracing.
My thought was to make the braces run longer, but I suppose with that I am constantly decrease net volume and shifting everything away from a tested design.
So you really addressed everything (and really well).
The last question I have is really related to that extension shelf. I am going to try and find a link the thread it was in.
Regarding the bracing, just a few posts above I see Art use one of my least favorite words "adequate" in terms of bracing.
My thought was to make the braces run longer, but I suppose with that I am constantly decrease net volume and shifting everything away from a tested design.
So you really addressed everything (and really well).
The last question I have is really related to that extension shelf. I am going to try and find a link the thread it was in.
http://www.diyaudio.com/forums/subwoofers/184986-horn-extender-wave-guide-th.html
So ya, first page Art had a link. Go figure.
So ya, first page Art had a link. Go figure.
The extender is a great idea.
Personally, for the logistics of packing, I'd make it in a 4 piece collapsible extender that either bolts, latches, clips, ratchets, etc together. A preassembled extender is a pretty bulky and odd piece to transport. A cabinet with built in extender is even worse than that in my mind.
Here's a bit of inspiration.
http://www.diyaudio.com/forums/subwoofers/170771-single-sheet-th-challenge-152.html#post3028901
Personally, for the logistics of packing, I'd make it in a 4 piece collapsible extender that either bolts, latches, clips, ratchets, etc together. A preassembled extender is a pretty bulky and odd piece to transport. A cabinet with built in extender is even worse than that in my mind.
Here's a bit of inspiration.
http://www.diyaudio.com/forums/subwoofers/170771-single-sheet-th-challenge-152.html#post3028901
This is probably a stupid question, but what high pass crossover point is suited for the Keystone to protect from over-excursion at high SPL, the amps I'm using are class A/B, will be bridged and put out 3500w at 4ohms, I had thought running it from 35hz up as that's what it was designed for but can I set it lower.....safely??
Regards,
Rowan
Regards,
Rowan
This is just on my hornresp sim so take it with a few grains of salt, but the lower excursion maxima becomes the same size as the midband peak at around 47hz with the highpass set at 25hz for Linkwitz-Riley and 29hz for Butterworth. The peaks are approximately the same size regardless of order used I discovered, interestingly.
That's using the logic that the highest excursion reached below the corner won't be any bigger than the excursion you'd see in the passband. Not sure if that's the best way to judge for filtering, but it makes sense to me at least.
I'd set it just a bit higher to save power/increase efficiency, reduce distortion and conserve excursion.
That's using the logic that the highest excursion reached below the corner won't be any bigger than the excursion you'd see in the passband. Not sure if that's the best way to judge for filtering, but it makes sense to me at least.
I'd set it just a bit higher to save power/increase efficiency, reduce distortion and conserve excursion.
Attachments
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MDF is not stiff, is heavy, and even when painted all sides is not suitable for outdoor use.
Los Angeles (Culver City) 90034
There is a place - Anderson Lumber that has the stuff, put they close at 4:30pm and are not open on the weekends. Rumor from a cabinet building friend is they may be around $120 I will call first thing tomorrow. If that is the cost, I just cannot swing that for 4 sheets. Logistically I will be working tomorrow a good 50 miles from there having to make through downtown LA at 3:30 pm to make it there in time. Lot of variables need to land perfectly for that to work out.
There is a place - Anderson Lumber that has the stuff, put they close at 4:30pm and are not open on the weekends. Rumor from a cabinet building friend is they may be around $120 I will call first thing tomorrow. If that is the cost, I just cannot swing that for 4 sheets. Logistically I will be working tomorrow a good 50 miles from there having to make through downtown LA at 3:30 pm to make it there in time. Lot of variables need to land perfectly for that to work out.
Thanks guys, 30 Hz BW24 it is.
I can't wait to start on this.
I have a set of Synergy Horns doing above 300hz
I'm building sealed enclosure with a set of AE TD18H+ doing 80-300hz
and the Keystones will do the rest.
Will post build pictures and final REW measurements once completed. Should take a few months as I've got lots on.
Rowan
I can't wait to start on this.
I have a set of Synergy Horns doing above 300hz
I'm building sealed enclosure with a set of AE TD18H+ doing 80-300hz
and the Keystones will do the rest.
Will post build pictures and final REW measurements once completed. Should take a few months as I've got lots on.
Rowan