Lab 12 Based Offset Driver - Mass Loaded - Transmission Line (OD-ML-TL) Design by Bj - Page 15 - diyAudio
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Old 9th May 2013, 12:11 PM   #141
DrDyna is offline DrDyna  United States
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Quote:
Originally Posted by NWCgrad View Post
GM, I am open to all ideas that maximize the potential of the LAB12 drivers for HT. Luckily DrDyna's TC Sounds Epic 12's model almost the same as the LAB12's, ecept for more Xmax resulting in greater SPL. I am stuck away from tools for several more months, this thread has had a way of evolving over time.

They always do meander a little bit, some of these guys have a way with changing even the most convinced of minds

Thanks for the links Oliver, I took a quick look and that's pretty much what I imagined, I'll have to dig around a bit in that thread for my "I gotta try this at some point" scrapbook
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Old 9th May 2013, 01:24 PM   #142
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I went to the linked thread and played around with Hornresp. I ended up with fairly decent SPL profile down to 19Hz before the rolloff, but the enclosure was huge. I am so not good at Hornresp.
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Old 9th May 2013, 02:35 PM   #143
tb46 is offline tb46  United States
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Hi NWCgrad,

For this type of TL you don't even need 3 sections in Hornresp, give it a try with OD and 2 sections, in the Wizard set S2 to Auto, that way you reduce the number of variables.

Gotta run,

Regards,
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Old 10th May 2013, 06:55 AM   #144
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Quote:
Originally Posted by NWCgrad View Post
GM, I am open to all ideas that maximize the potential of the LAB12 drivers for HT.
Hmm, I haven't followed the forums much for awhile now, but thought your sub system had already been worked out in a long thread quite awhile back.

Regardless, the needs of the app dictate the driver's specs, alignment, so don't know if the LAB 12 is even the right driver for yours.

FWIW, it's just a 'bulletproofed' Avatar/Adire Audio Shiva designed principally for car audio apps in the late ‘90s, so has some history in various vented, sealed, PR and BP alignments.

Personally, I used a pair + their 15" PRs to create a mini-Contrabass for a friend since it was a bipolar alignment in approximately the same cab layout, net Vb [~8-10 ft^3, I forget now] as Tom Danley's Servo-Drive Contrabass servo sub.

Tuned to ~14 Hz with 300 W/driver, it shook my old floating floor, stick built house pretty good back when the movie U-571 was the low bass reference recording and gave a more 'solid' performance at THX/DD/DTS reference in a below grade poured concrete basement HT app.

In a ˝ WL long, low tuned tapped pipe horn similar to the DSL DTS10 and limited to the same ~two octaves, it will theoretically match it performance except for peak power handling, but the trade-off is a ~854 L net Vb cab, so wouldn’t be my first choice unless the room is either at least medium size, but allows optimum positioning or quite large for multiples based on the trials n’ tribulations of the folks using the DTS10: Danley DTS-10 "Super Spud" DIY kit

Simple bi-fold ‘BIB’ concept corner pipe horns are probably a better choice overall in most apps that allow multiple large cabs; otherwise, PR vented cabs are going to be the best bang/buck in a relatively small cab AFAIK, especially if a > ~60-80 Hz XO point is desired.

GM
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Old 10th May 2013, 11:31 AM   #145
DrDyna is offline DrDyna  United States
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Quote:
Originally Posted by tb46 View Post
Hi NWCgrad,

For this type of TL you don't even need 3 sections in Hornresp, give it a try with OD and 2 sections, in the Wizard set S2 to Auto, that way you reduce the number of variables.

Gotta run,

Regards,
LOL, that's a heck of a bomb to drop, it looks like the response is nearly the same!
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Old 10th May 2013, 11:55 AM   #146
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I've decided that I'm just going to build the "proper pair" with mdf again because it's cheap and I keep going through and trying different designs, so there's no telling how long I'll have them. They're about 80% completed right now, I just have to finish working on the S3-S4 angled pieces (that are giving me grief, my old saw just doesn't cut like it used to!).

Before I button it up this afternoon, I do have one remaining question. From the worksheet posted by bjorno, it appears that the S1-S2 stuffing should be fairly thick and S3 should be thinner. I'd like to make sure that I have the stuffing perfect before I PLP the side on, can anyone confirm the appropriate stuffing amount? I'm planning on using a roll of fiberglass insulation because I have it handy already.

Edit: oh, and lordy, placement options abound, with the usable frequency response up to nearly 130 cycles, I'm wondering if these should become my new stands for mains. Might be a tradeoff, not using corner placements, but it seems like integration would be much better.

I sense lots of measurements and fiddling this weekend.
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Old 10th May 2013, 01:45 PM   #147
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Awesome, can't wait for the results. I am confounded by all the different design potentials.

tb46, I will fiddle with Hornresp when I get a chance. Thanks again!
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Old 10th May 2013, 03:07 PM   #148
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Originally Posted by DrDyna View Post
I've decided that I'm just going to build the "proper pair".............
which are........??

GM
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Old 10th May 2013, 03:22 PM   #149
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Originally Posted by GM View Post
which are........??

GM
The OD-ML-TL, my usage of proper pair was a contrast to the hastily assembled test version I did with a single driver just to see what the performance would be like.

That TQWT Oliver posted, which I believe to be along the lines of what you were talking about, is probably next on my project list, but I'll fire up a build thread if I do a couple of those.

Last edited by DrDyna; 10th May 2013 at 03:25 PM.
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Old 10th May 2013, 05:00 PM   #150
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Quote:
Originally Posted by DrDyna View Post
I've decided that I'm just going to build the "proper pair".............
which are........??

GM
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