Lab 12 Based Offset Driver - Mass Loaded - Transmission Line (OD-ML-TL) Design by Bj - Page 26 - diyAudio
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Old 4th June 2013, 03:19 PM   #251
DrDyna is offline DrDyna  United States
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Quote:
Originally Posted by NWCgrad View Post
Now that is a center channel, I bet it can keep up with most any mains. Nice! Glad to see the subs are working out. I have the movers packing my drivers tomorrow for the slow boat back to America, didn't want to keep them in the enclosures because they seemed safer in original packaging.
Ha, yeah, its different from the old one for sure, and it cured a big problem I had with the subs at the back of the room, deep voices rumbled way too much from the back of the room which made it a little bizarre, but I was able to set the center crossover in the htr to 40 hz so that problem is gone.

Now the plan is another pair at some point and a bigger amplifier. I'm not sure if I'll get another behringer or not, I was thinking about one of the bigger crowns that have DSP, but I'm not sure yet. Either way, its gonna be a few months before I do any of that.

Edit: yeah, I always keep my boxes for packing too, the drivers are probably heavy enough to break the box if its mishandled...plus if anyone else handles it, its easier to carry the original boxes around without dropping them than that 120lb subwoofer.

Last edited by DrDyna; 4th June 2013 at 03:46 PM.
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Old 4th June 2013, 06:58 PM   #252
Zero D is offline Zero D  United Kingdom
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@ DrDyna

Thanks for the pics Those surrounds @ the couch position sunk into the wall are a neat idea

It never ends does it
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Old 6th June 2013, 01:07 PM   #253
DrDyna is offline DrDyna  United States
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@ DrDyna

Thanks for the pics Those surrounds @ the couch position sunk into the wall are a neat idea

It never ends does it
No problem, and thanks! The plan is to have all 4 of the rear surrounds in the wall, but I'm still having leaking issues with that back wall, so I can't finish it until I fix it.

Yeah, it really does never end, lol.
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Old 15th November 2013, 05:54 PM   #254
NWCgrad is offline NWCgrad  United States
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I am finally settled in back in the US. Re-reading this thread to decide how to go. I am thinking of building the tb46 iteration as no one has and DrDyna built the first iteration.

Will try to make sawdust in next couple of weeks. I am slow due to family and work travel.

Right now I have the Lab12's in the sealed enclosures running with my sealed Maelstrom X. Sounds great but low end is missing. Could just do an L/T circuit with my miniDSP as I don't listen that loud in my townhome (usually -10 dB from THX reference). But I think I may be happier with the TL design to get solid 20 Hz performance without stressing the drivers, I am assuming will have lower THD.
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Old 15th November 2013, 10:17 PM   #255
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Default I like the OD_ML_TL's

The first design (OD_ML_TL) does not have the visceral, in your face thump that some subs have but they are very "musical" and integrate easily with my sound system.
I have a pair of 12", 73 liter woofer boxes that have an in room rising response down to 35 Hz and when I have the OD_ML_TL's on, but not cranked all the way up, it really seems that all the low bass is coming from the 73 liter woofer boxes.
It really fools me even though the OD_ML_TL's are 5 ft. away from my chair vs. 13 ft. for the woofer boxes.
However, when I turn off the sub amp, the 73 liter woofers suddenly seem a little lame.
I presently have the subs right next to each other for the mutual coupling gain.
I removed most of the stuffing between S2 and S3 and both the SQ and the SPL got better.
.
If you decide to build the TQWT's it will be interesting to see what the difference is.
Either way, best of luck with your build.
Also, I thank you for recommending the Crown xti-1002 amp. I really like it.

Dave
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Last edited by Shadydave; 15th November 2013 at 10:24 PM. Reason: corrected distance reference
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Old 15th November 2013, 10:32 PM   #256
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Shady,
The comparison of your 2 sub systems isn't really accurate as they are separated by 8' and so activating different nodes in your listening space. To gat an accurate idea which system is hitting which notes you'll have to swap them in and out of a common location and evaluate from your listening seat.
One way to find the best position for a subs is to flip the system around and place the sub at the listening location and then crawl around to placement locations and fin the most suitable response. This may really help you place the second system for most complimentary output to your first system.
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Old 15th November 2013, 11:40 PM   #257
NWCgrad is offline NWCgrad  United States
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Quote:
Originally Posted by Shadydave View Post
The first design (OD_ML_TL) does not have the visceral, in your face thump that some subs have but they are very "musical" and integrate easily with my sound system.
I have a pair of 12", 73 liter woofer boxes that have an in room rising response down to 35 Hz and when I have the OD_ML_TL's on, but not cranked all the way up, it really seems that all the low bass is coming from the 73 liter woofer boxes.
It really fools me even though the OD_ML_TL's are 5 ft. away from my chair vs. 13 ft. for the woofer boxes.
However, when I turn off the sub amp, the 73 liter woofers suddenly seem a little lame.
I presently have the subs right next to each other for the mutual coupling gain.
I removed most of the stuffing between S2 and S3 and both the SQ and the SPL got better.
.
If you decide to build the TQWT's it will be interesting to see what the difference is.
Either way, best of luck with your build.
Also, I thank you for recommending the Crown xti-1002 amp. I really like it.

Dave
I am glad you like the Crown. I am looking for subs for music. Have the 18" sub for HT. For music I plan to only use the Lab12 design. The second looks easier to build, but the first fits my intended space better.

Will do the sub crawl for the 18" beast for maximal excursion. If the two systems don't play well together I will look to build a new sub for HT.
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Old 6th December 2013, 01:39 AM   #258
NWCgrad is offline NWCgrad  United States
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Default And so it begins....

After months of planning, changing directions, and rethinking I am moving forward building a pair of the transmission line subs. tb46 has developed a smaller form factor of his design from a few pages back and is currently finalizing putting the "electron" model into a "wood" plan. I was going to go many different ways as I kept changing my mind, but at the end of the day I wanted to do something different.

Based on latest iteration of the plan, the enclosure will measure 25.5" H x 25.5" D x 16" W. Once finalized I will post and develop the cut sheet. Dual subs will be powered by an Adcom GFA555 amp (for now).

Internal dividers will have around a 3.2 degree angle. I remember reading on one of the tapped horn build threads that when using PL adhesive you don't have to cut the panels to exact degree. Would appreciate any feedback on whether I need to cut the internal dividers at the angle or will the PL adhesive fill the gaps?

I am hoping for an in room response of 115 dB @ 1 M per sub (250 W/4 ohm input). I guess time will tell. I have REW and a calibrated Cross-spectrum Labs calibrated EMM-6 USB microphone. Once subs are built I will try to figure out room measurements.

My space is rather large (~4,800^3) but these two subs will be used as flanking subs for my 4 Pi speakers. I primarily listen to music (75%). For HT they will be paired with an 18" Maelstrom-X sub (sealed, 5.9 ft^3, Qtc: 6.5) powered by a QSC RMX1850HD amp. For eq I have a miniDSP (2x4), Behringer DSP1124P and Behringer FBQ2496.

Hope to start sawing wood in next couple of weeks, but the holidays may intervene.Click the image to open in full size. Will post photos as time allows.

Thanks for reading, hope these turn out well....
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Old 6th December 2013, 06:29 AM   #259
GM is offline GM  United States
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Quote:
Originally Posted by NWCgrad View Post
I remember reading on one of the tapped horn build threads that when using PL adhesive you don't have to cut the panels to exact degree.
Except for any visible in the mouth, I've never cut any dividers at an angle for a HIFI/HT app, usually just a free hand 90 deg cut. I draw a line where the edge of the board goes, lay down a 'bed' of adhesive along it, insert divider and run a bead across the gap once clamped in place. Works just fine with Titebond or similar also, though for wide gaps I mix in some sawdust or similar to make a paste to putty knife/squeegee to fill the gap somewhat.

Angles and dado-ed joints are nice, but only a good plan for a prosound, industrial or similar app IME.

GM
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Old 6th December 2013, 01:01 PM   #260
NWCgrad is offline NWCgrad  United States
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Thanks GM! I definitely prefer working with Titebond vice PL. To bad I don't have a jointer as it would make creating the proper angles a piece of cake.
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