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Old 12th November 2013, 05:11 PM   #1991
jwmbro is offline jwmbro  United States
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Originally Posted by sine143 View Post
I have not seen a better design for the 15tbw100 yet. granted it doesnt go super low.
FWIW, the 15tbw100 also sims fairly well in the 'cone volume correction' style SS15 (here's a photo of the one I built, I think there are plans somewhere in this thread too) that has been discussed here, which is in my humble opinion probably the optimal version of SS15 (I think Djim came up with it? not sure). The regular SS15 will most likely perform almost as well, I just didn't have the HornResp entry data handy.

Here's a sim of it at xmax, hyperlinked in order to not clog up the page with images, as you can see it's a bit peakier than my design, due to the relatively lower compression ratio, but it plays a bit louder (hoffman's iron law at work - the box is a cubic foot larger).

A matter of preference I think. The SS15 may be easier to saw, since I havent worked on a cutsheet for the other design yet.

EDIT: And of course both of them only play down to 40Hz, this is not the sub for you if you want lower content than that, I imagine the 15tbw100 would do well in the 15" Keystone sub, or several of the other designs aimed at lower response that can be found in this forum. Try em yourself, I'd look at the C/E/X horn, the Keystone, maybe the PAL-12 and probably a few more I can't think of right now.
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Last edited by jwmbro; 12th November 2013 at 05:19 PM.
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Old 12th November 2013, 05:27 PM   #1992
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Thanks sine143. But for a bit more money, the 18TBW100 in a Keystone TH looks really good.
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Old 13th November 2013, 04:52 AM   #1993
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Originally Posted by mwmkravchenko View Post
I'm still interested.

Pretty sure David McBean will be interested to!

No mean feat to develop a folding aid like you are showing.
Here's what the latest version looks like. I think I've worked out all the bugs (including a major one that basically indicates that my POC3 design is a lot longer than I planned, groan).

If you'd like to give it a spin, let me know. I'll likely add it to the "spreadsheet" thread in a week or two anyway, once I've completed POC3 and had a chance to compare predictions to actual results.
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File Type: jpg 20131113-STH41..jpg (339.6 KB, 424 views)
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Old 13th November 2013, 08:03 AM   #1994
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Brian, is that design still a single sheet? If so, it looks really nice!

I built two SS15s a while ago, but they are not completly finished yet, so havent really tested them.
I used Xoc1´s extended version as a baseline, and then I tweaked it to better suit the new version of the Kappalite 3015LF´s that I have, I also tweaked it so all the panels actually fitted on a 12x1220x2440mm sheet, with sawblade margins

I simulated a couple of different versions with more cone correction, but they actually gave a slightly worse result than what I ended up building.

If any one wants more drawings or such for this version, ask me and I can send autocad drawings with all measurements.

But beware, I went a bit of the single sheet thinking here, all the 12mm panels fit one sheet, with not much more than dust left, but all the bracing and reinforcements for the handles are made from 9mm, I used about a half sheet of 9mm for two cabs. So, they arent really SS15´s :P
All the braces are double, I used them as moulds during the build, they were all routered with cnc-cut aluminium molds, fancy, I know

Some pictures here:
https://drive.google.com/folderview?...Hc&usp=sharing

Would be interesting to simulate "my" version of the SS15 with the 15tbw100 or some other nice 15", I´ll do that some day :P
But for now I think I´ll be using the 3015s that I have, I have 2 more sitting in T48s also that probably will get SS15 cabs if the first two works out good.
Attached Images
File Type: jpg Xoc1 SS15 RL mod HR input.jpg (95.6 KB, 382 views)
File Type: jpg Xoc1 SS15 RL mod SPL Response.jpg (73.7 KB, 362 views)
Attached Files
File Type: pdf Xoc1 SS15 RL mod.pdf (13.9 KB, 42 views)
File Type: pdf Xoc1 SS15 RL mod Cutsheet 12mm.pdf (58.1 KB, 31 views)

Last edited by Robin N Zone; 13th November 2013 at 08:30 AM. Reason: Forgot the attachments..
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Old 13th November 2013, 11:40 AM   #1995
Mark Kravchenko --- www.kravchenko-audio.com
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Brian I sent you P.M.
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Old 2nd January 2014, 11:51 PM   #1996
jwmbro is offline jwmbro  United States
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Originally Posted by jwmbro View Post
Here's the 15SW115 sim if anybody is interested, it's 4" narrower (so another cu ft or so smaller) and goes 1dB louder. But like I said, not really in the spirit of this thread with a 500$ driver.
A small design like this needs quite a powerful driver (strong magnet and high power handling), which are typically fairly expensive.

However Dayton is set to release their new line of PA drivers, "inspired by popular Italian made pro audio drivers" and this PA385S-8 15" driver specifies a BL of 31Tm and a 1kW power handling at under 200$.

Much of this design hinges on whether this driver will live up to its specs when released (was supposed to be available from today, but seems to have been pushed back). If it does however live up to these, I think I have a potential SS15 alternative design (if you're willing to accept the tradeoffs it makes) that is definitely worth submitting here.

Click the image to open in full size.

It measures 64 x 64 x 43 cm (25 x 25 x 17 inches) and at 150l internal volume (about 6 cu ft external volume) it is quite a bit smaller than the SS15, and as a result of this unsurprisingly is about 2dB less sensitive. The flipside though is that it will play a few Hz deeper (flat down to an F3 of 40Hz even from a single cabinet) and due to much higher power handling should play 2dB louder at full blast.

The Dayton driver is quite heavy, so even though the box is quite a bit smaller, it will definitely be heavier than jbell's SS15. But if space is at a premium, and load weight & amplifier power are not, I think this is a pretty good bet. It'll require an amp that will do about 100V, but these can be had fairly cheaply these days. I figure you could run 4 of these from a single Behringer NU6000DSP, which is about 137dB flat down to 40Hz according to HornResp. Not bad from about 1600$ worth of parts total (the design is definitely easily single sheet, I did a quick and dirty cut sheet to make sure).

Keep an eye on this thread for reports on real world performance of these drivers. If they can take the 2kW peaks they are rated for, and the cone will handle a 4:1 compression ratio while moving 1cm each way, it looks like a Goliath-killer to me.
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Old 3rd January 2014, 12:04 AM   #1997
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Originally Posted by jwmbro View Post
Not bad from about 1600$ worth of parts total (the design is definitely easily single sheet, I did a quick and dirty cut sheet to make sure).
You're going to need to put a lot of bracing into that build, especially the top panel, which is going to increase amount of wood you'll need to use. One of the beauties of the "SS15" fold to me is that one of the panels actually acts as a cross-brace for the top of the enclosure, so theoretically you could get away with less bracing at that point.
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Old 3rd January 2014, 12:33 AM   #1998
jwmbro is offline jwmbro  United States
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Originally Posted by Brian Steele View Post
You're going to need to put a lot of bracing into that build, especially the top panel, which is going to increase amount of wood you'll need to use. One of the beauties of the "SS15" fold to me is that one of the panels actually acts as a cross-brace for the top of the enclosure, so theoretically you could get away with less bracing at that point.
Maybe so, but my top panel is 25x16" - the back panel of the SS15 is 29x21" and that one doesn't have any inbuilt bracing. I think if you can get that braced up enough, the massive 8 food long strip of material left in the sheet should be enough to get the top panel vibration free.

Though in a sense I agree with you - if that driver can truely do 127dB power compression free (remains to be seen), you're going to have a lot of pressure in the enclosure, might as well spring the extra 10kg or so of weight and make it out of 18mm ply. Though you'll be at over 40kg total weight then. For me the SS15 is more bulky than it is heavy, at least for a one-man carry job, I think I'd prefer to have it smaller than to have it lighter (bear in mind mine is using an iron magnet version, not the super light neo 3015lf either).

Even so, the angled bottom edge will nicely fit two fixed casters, making it super easy to roll.
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Old 3rd January 2014, 01:02 AM   #1999
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Maybe so, but my top panel is 25x16" - the back panel of the SS15 is 29x21" and that one doesn't have any inbuilt bracing.
Based on my results from a similar build, the back panel isn't as prone to vibration as the top and bottom panels, which I think is likely due to their various positions along the horn's path. The impact of any panel vibration at the back is a lot less as well, as any significant vibration of the top and bottom panels can add significant measurable distortion if that vibration brings them into contact with another surface, e.g. the floor or a "top" mounted on top of the subwoofer box. I once measured a significant increase in distortion from my POC #1 TH build that turned out to be caused by a small stone caught between the bottom panel and the ground, LOL. The use of two "rails" near the outer edges of the bottom panel eliminated this problem from happening again.


Quote:
Originally Posted by jwmbro View Post
I think if you can get that braced up enough, the massive 8 food long strip of material left in the sheet should be enough to get the top panel vibration free.

Though in a sense I agree with you - if that driver can truely do 127dB power compression free (remains to be seen), you're going to have a lot of pressure in the enclosure, might as well spring the extra 10kg or so of weight and make it out of 18mm ply. Though you'll be at over 40kg total weight then. For me the SS15 is more bulky than it is heavy, at least for a one-man carry job, I think I'd prefer to have it smaller than to have it lighter (bear in mind mine is using an iron magnet version, not the super light neo 3015lf either).

Even so, the angled bottom edge will nicely fit two fixed casters, making it super easy to roll.
One possibility is using a mix of panel thicknesses, e.g. thinner ply for the internal panels and thicker ones where the horn would be subject to the most vibration. It may take a couple of iterations to get the perfect mix though, and of course you'll no longer be using just one sheet of ply (maybe two half-sheets can count as one sheet in the challenge? )
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Old 3rd January 2014, 01:09 AM   #2000
sine143 is offline sine143  United States
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Originally Posted by Brian Steele View Post



One possibility is using a mix of panel thicknesses, e.g. thinner ply for the internal panels and thicker ones where the horn would be subject to the most vibration. It may take a couple of iterations to get the perfect mix though, and of course you'll no longer be using just one sheet of ply (maybe two half-sheets can count as one sheet in the challenge? )
As is used in the Ricci's othorn (which this fold is based off of)

Seriously though, its not that difficult to brace effectivly.

I'd consider adding an extra layer of 1/2 ply on the rear 45 angle piece (for caster mounting). a couple months of lugginb will form cracks there.

what are the effects of shrinking S1 (ala Othorn) for extra bracing of the driving mounting panel?
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