fhperez:
Thanks for the update.
Yes these are light. I do installs, and handling a sub 30' in the air makes a person think twice about every pound of weight. I never want to install a heavy weight sub again. I had to go see the chi-o and have my back cracked after my last 150lb sub installation. 42lbs for a sheet of auroco, 7lbs for a 3015lf plus paint and hardware. Basically a 50lb sub. The entire point of this thread for 'single sheet' was primarily due to weight and simple design. I needed a lightweight design I could kick out in part of a day.
Yes, they can walk. The 'bottom' as you have them pictured only has a single brace, which is where the walking is coming from. More bracing would eliminate some cabinet flex and some walking, but then I designed this as an install sub. More bracing = less spl and more weight in my experience, and I am more than willing to allow a 'little' cabinet flex. I would personally bring a small carpet with rubber backing instead of rubber feet. Feet tend to get torn off of a cabinet.
2 tops per sub??? That is blasphemy to many people. There are those who advocate at minimum 2 subs per top. 2 of the SS15's keeping up with 4 EV's at war volume is a pretty good testament to this design. I will repeat scott's comment about TH's. "They bloom at war volume, reflex boxes wilt."
How did the texture gun work out? Couldn't tell much about the finish from your posted pics.
On the osx on 'other' hardware sites, they have listed which motherboards are fully compatible and which aren't. If you want a full size box, start with the motherboard and put it in whatever case you want. The 10v is really a nice little osx machine.... that's why I recognized it
Thanks again for the update -- I really like this design. It's only real downfall is it's a little short in the 40hz department in single cabinets. To hear your dj friend say it was 'loud and low' from across the hall when running pairs made me smile.
Jbell, you state that "more bracing=less spl". Can you elaborate. I'm new to TH. My prior understanding was a stiffer box was always more desirable.
Thanks
DLStryker
less bracing = more vibration of the box walls.
That vibration is sound output. Some of this sound output is at frequencies where the panels have a high Q and this increases the total acoustic power delivered by the "speaker".
For accurate bass reproduction we try to eliminate the resonances and give the speaker a reasonable chance of giving a "flat" output. This reduced distortion output is cleaner but less loud.
That vibration is sound output. Some of this sound output is at frequencies where the panels have a high Q and this increases the total acoustic power delivered by the "speaker".
For accurate bass reproduction we try to eliminate the resonances and give the speaker a reasonable chance of giving a "flat" output. This reduced distortion output is cleaner but less loud.
Hi there: Without rdesigning JBELL's one sheet box, an experimental stiffer box could be constructed ( with the exact internal volumes ) by using laminated internal components and external walls braced with studs and beams. Using the same driver for both types of construcion, tests could then determine if SPL reduction is caused by panel vibrations or the inclusion of internal bracing ( which reduces internal volumes ). 3/4" laminates could be made from 1/2" plywood with both sides bonded with 12gage sheet steel or fiberglass over 1/2'' ply. ...regards, Michael
A simpler way, if all we're testing for is the difference caused by panel flex, is to clad the external panels of the box with an additional layer of 3/4 ply. The internal volumes and dimensions will remain the same, but the box should be quite a bit stiffer (and heavier, LOL).
I built Jbells ss15
Well, JBells got a real winner with the ss15. And we are all the better for it due to his sharing this amazing design. I just finished the internals this afternoon, used tape and foam to seal the seams and ran a level test. I used a ratshack digital meter, 2.83v at one meter. A few things different. I made the exterior of the box out of 3/4 ply. The extra 1/4" of wood is outside of the plan dimentions so the internal dimensions are too plan. Secondly when I bought my 1/2" ply for the internals a grabbed a 5/8" sheet someone had put on the stack without my realizing it. It wasn't till late this afternoon that I realized the error. Luckily for me I doesn't seem to have hurt a thing. The difference in thickness is evenly divided on each side of the layout lines. I decided to test it first without bracing to see the results. Tomorrow i"ll open it up and brace it, just to see if it affects the results. Maybe do it several times to see how much bracing I can get away with. I think the way it is I can hear panel resonance, but i'm not sure.
MY AMP has a 50hz hi pass filter which I didn't disconnect. So the bottom end will be better than measured, without it.
Here are the results:
40hz 101db
45hz 104db
50hz 108db
55hz 109db
60hz 111db
65hz 111db
70hz 112db
75hz 112db
80hz 110db
85hz 112db
90hz 113db
95hz 112db
100hz 113db
105hz 112db
110hz 112db
115hz 113db
120hz 113db
A couple questions: Is there any reasons to test it at higher frequencies, since i'll probably cross it over around 120hz?
Will putting a speaker jack plate in the back mess with the responce?
I'm assuming cutting a hole to insert a handle is a bad idea?
This is my s**t eating grin:
Well, JBells got a real winner with the ss15. And we are all the better for it due to his sharing this amazing design. I just finished the internals this afternoon, used tape and foam to seal the seams and ran a level test. I used a ratshack digital meter, 2.83v at one meter. A few things different. I made the exterior of the box out of 3/4 ply. The extra 1/4" of wood is outside of the plan dimentions so the internal dimensions are too plan. Secondly when I bought my 1/2" ply for the internals a grabbed a 5/8" sheet someone had put on the stack without my realizing it. It wasn't till late this afternoon that I realized the error. Luckily for me I doesn't seem to have hurt a thing. The difference in thickness is evenly divided on each side of the layout lines. I decided to test it first without bracing to see the results. Tomorrow i"ll open it up and brace it, just to see if it affects the results. Maybe do it several times to see how much bracing I can get away with. I think the way it is I can hear panel resonance, but i'm not sure.
MY AMP has a 50hz hi pass filter which I didn't disconnect. So the bottom end will be better than measured, without it.
Here are the results:
40hz 101db
45hz 104db
50hz 108db
55hz 109db
60hz 111db
65hz 111db
70hz 112db
75hz 112db
80hz 110db
85hz 112db
90hz 113db
95hz 112db
100hz 113db
105hz 112db
110hz 112db
115hz 113db
120hz 113db
A couple questions: Is there any reasons to test it at higher frequencies, since i'll probably cross it over around 120hz?
Will putting a speaker jack plate in the back mess with the responce?
I'm assuming cutting a hole to insert a handle is a bad idea?
This is my s**t eating grin:
Hi runrod1948,
I don't think the material thicknesses will adversely affect the performance of this box, it'll be heavier though.
As to your question: "...Is there any reasons to test it at higher frequencies..", it would be nice to see if the upper peaks and valleys we see in Hornresp are there or not, particularly the deep null around 330Hz. Also, well sealed speaker plates or handles (within reason, in the bigger bends) will not affect the performance.
Looking forward to your data with different bracings.
Regards,
I don't think the material thicknesses will adversely affect the performance of this box, it'll be heavier though.
As to your question: "...Is there any reasons to test it at higher frequencies..", it would be nice to see if the upper peaks and valleys we see in Hornresp are there or not, particularly the deep null around 330Hz. Also, well sealed speaker plates or handles (within reason, in the bigger bends) will not affect the performance.
Looking forward to your data with different bracings.
Regards,
Totally have to walk before you can run...
I'd be happy with 1/24 oct freq/phase/impedance charts... done in a repeatable ground plane fashion.
Every time I hear jbell's box measures better than it sims, i'm just curious why the th designs with lots of solid data measure close or very close to an accurate sim.
The boxes I'm thinking of are lilmikes shiva, 6.5" anarchy, th-spud, brians POC, wood1y's http://www.diyaudio.com/forums/subwoofers/170749-15-tapped-horn-rcf-6.html#post2289368 all have appeared to be measured accurately and to my eyes are close to the sim.
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I also made my ss15s with 3/4 external by adding a half inch to the side panels in both dimensions.
Those numbers seem a bit optimistic though dont they? Even if they are, if still measures really really flat! Ive not tested my pair yet but i'm really really happy with them. They have gone straight into service with gigs about 5 nights a week. i will be building a whole shed loads more.
Those numbers seem a bit optimistic though dont they? Even if they are, if still measures really really flat! Ive not tested my pair yet but i'm really really happy with them. They have gone straight into service with gigs about 5 nights a week. i will be building a whole shed loads more.
I'm a bit of a noob at this, so I don't understand what you mean by "skewed".
In what way? What is "weighting"? distance from mouth to meter was posted.
one meter. voltage was 2.83 volts. I'm assuming the voltage doesn't have to be reset for each frequency change? Each burst of the sine wave was for three seconds and each frequency was run three times. there was no wind. the meter was on a stand pointed at the center of the horn opening. I was as carefull as I could be. I'm not interested in fooling myself, or others, with bogus numbers. The meter does have a possible inacuracy of +- 2 db though. that's the specs given. Yes, the numbers seem almost unbelievable, I can't dispute that and I can understand the doubts in peoples minds. If it helps, I would be willing to post actual video of the test in progress, too alleviate all doubt.
tb46:
I'll be doing the first bracing test today. I've got a bad feeling about it though. Somewhere on this site, I read a post stateing that panel resonance can smooth out a responce curve. I've got a feeling that the agressive use of bracing may have been an issue with the last cab I built.
Anyone have any thoughts on this?
Dave nonzero:
did you ever run a test on your cabs? would love to see your results.
Hi runrod1948,
I think your testing is fine for a starting point, and should be repeatable, that's really more important than the absolute accuracy. I is a heck of a lot better than anything I've been able to find time for in the last year. Thanks.
My past experience with inadequate bracing has always been a loss of output at the frequencies where a panel is resonating. In a tapped horn that may reduce an unwanted peak, but I doubt that it can fill in a dip in the response. So it would be interesting to see if that still holds true. Bracing could reduce the cross-sectional area of the horn, and that should be taken into account (particularly in the throat area), but I doubt the area reduction matters much in the large sections of a tapped horn.
Regards,
I think your testing is fine for a starting point, and should be repeatable, that's really more important than the absolute accuracy. I is a heck of a lot better than anything I've been able to find time for in the last year. Thanks.
My past experience with inadequate bracing has always been a loss of output at the frequencies where a panel is resonating. In a tapped horn that may reduce an unwanted peak, but I doubt that it can fill in a dip in the response. So it would be interesting to see if that still holds true. Bracing could reduce the cross-sectional area of the horn, and that should be taken into account (particularly in the throat area), but I doubt the area reduction matters much in the large sections of a tapped horn.
Regards,
runrod:
I've never had an issue with 'hollow' bracing, only solid bracing. In particular a solid brace down the back cuts 40hz response by a couple db.
brace away, just keep it as open as possible.
I too think 111 is a bit optimistic, sounds like your ratshack is reading a bit high. Other than that, looks like the nice flat numbers I would expect, with the addition of more drop off due to your 50hz high pass.
glad you like your cabinet... it's one of the few designs of mine I'm happy with.
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Does the poster say what signal voltage or what driver impedance he used for the test?
Or is he simply giving us his results for a comparative frequency response based on his test conditions?
I decided to have a go at plotting out the horn dimensions 'as drawn' to try to fathom out what is going on with this sub.
The results of the unfolded taper are reasonably linear apart from two restrictions.
When I sim with these results, and adjust the level to 7.5 V to match Runrods sensitivity readings it tracks his results within his 2db tolerance level.
Then I notice that Runrod says he is running a 50hz hi-pass (the plot thickens!)
The results of the unfolded taper are reasonably linear apart from two restrictions.
When I sim with these results, and adjust the level to 7.5 V to match Runrods sensitivity readings it tracks his results within his 2db tolerance level.
Then I notice that Runrod says he is running a 50hz hi-pass (the plot thickens!)
