ShadyDave and DrDyna, thanks for posting your results (even the subjective junk...I am glad to see they are easy to integrate with mains as I am planning to use mine as flanking subs (assuming I ever get re-assigned out of Asia).
The TC Sounds drivers do model well in this design, although they seem to work in most Lab 12 designs, except play louder to their greater extension.
The TC Sounds drivers do model well in this design, although they seem to work in most Lab 12 designs, except play louder to their greater extension.
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Yeah, integration was really pretty easy here. It might even be easier once I've got two of them going, but for right now, I've just got them going directly from sub outputs to amplifier. I haven't even fussed with the MiniDSP, I've just got the amplifier gain set a couple of ticks lower than "noon" on the knobs and its basically forgotten. Granted that may change once I've got the media room sorted out and everything is back down in the larger room, but for now, its a very pleasant subwoofer that seems to have very few attitude problems.
I've sorta asked this before about the single fold design, but just to make sure, would there be any issues with building it like this? Or with the driver inverted?
(pardon the crudeness of my mspaint skills.)
Edit: I guess what I'm asking is, before I get creative, is there any style of folding or not folding that will affect the performance in any appreciable way?
(pardon the crudeness of my mspaint skills.)
Edit: I guess what I'm asking is, before I get creative, is there any style of folding or not folding that will affect the performance in any appreciable way?
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I rather agree, however (and I'm still learning about horns) I think the way the driver is positioned along with the thin-long design plays a role in tuning resonances, along with the way the upper end of the line should be stuffed, as I understood, lightly and increasing to heavy toward the far end.
If I build a proper pair of these once I can come up with a wacky design that I like, I'm not opposed to knocking the "internal artwork" out of this test cabinet I have now and measuring the difference.
I just need to come up with something artistic that doesn't compromise the performance before I start cutting BB.
I was more or less just going to use the existing cabinet without the pieces that make up the fold, or even just reach in through the driver opening and poke a half dozen holes in it with a 4" hole saw.
According to Bjorno it is an Offset Driver Mass Loaded Transmission Line (OD ML TL), I searched the design on the Internet but didn't find much. Apparently the top section (ie above the driver) loads when the speaker is powered and acts as a spring to force sound waves through the "port." A typical ported design does not "mass load" in this matter. I am far from knowledgeable on speaker design and Bjorno seems to have dropped off the site.
Would be interesting the compare a traditional ported design tuned to the same value. Is there a measurable or audible difference? Traditional ported would be a much simpler build.
I wish I could change the name of the thread to OD-ML-TL vice T-TQWP. I was after a T-TQWP design to match the one Bjorno developed for my Maelstrom X 18" driver. I have heard it can be hard to mix sub types in a common space and obtain good results.
You should be able to get a moderator to change the topic, I remember reading that the design was really an OD ML TL, but if a few days goes by before I see the thread again, the topic always puts QWP back in my head when I'm discussing it.
I think the long box will sound different. It reminds me of a truck box verses a trunk box. Truck boxes don't sound deep to me due to the lack of depth behind the speaker. HR shows depth affects group delay, phase response, and diaphragm displacement regarding a Kicker 08S15L74 in 2.5ft3 sealed enclosures with 8" (truck box) and 16" (trunk box) depths.
Well, I can tell you, even with one of these playing, wired 4 ohms on one channel of an ep2000, its anything but shallow, its got a pretty nice thunderous growl to it.
I need to work up the ambition to go out in the garage and get my stupid measurement mic.
I'll probably do it tomorrow, I need to measure it like it is first and MiniDSP any issues out of it first before I change it.
I'm still pretty convinced that I'm going to build a proper pair of these though.
Have you drilled the holes? How many of the inner partions can you reach from the driver mounting hole?
I hope we see a measurable difference, would emprically show mass loading is a real phenomenon and not just theoretical mamby pamby (precise engineering language could be substituted here).
I think two of these wil be great for the two channel rig, not sure how well they will work for HT as the don't dig below 20 Hz. The Labs 12s sound great in the temp sealed boxes I am using now, but they start rolling off to early (around 40 Hz). To counter, I have bumped up a bit with an LT via the miniDSP - but have to be careful with low end boost and cone excursion.
I don't get LT in practice. When modeling LT in winISP you have to reduce power significantly due to cone extension at the boosted frequencies, looking at before and after plots it seems it would be easier to use a shelf filter to bring down the higher frequencies instead of boosting lower. Overall the effect is almost identical if looking at max SPL at a given frequency below the LT boost due to reduced power handeling. Perhaps I am using the modeling incorrectly.
I hope we see a measurable difference, would emprically show mass loading is a real phenomenon and not just theoretical mamby pamby (precise engineering language could be substituted here).
I think two of these wil be great for the two channel rig, not sure how well they will work for HT as the don't dig below 20 Hz. The Labs 12s sound great in the temp sealed boxes I am using now, but they start rolling off to early (around 40 Hz). To counter, I have bumped up a bit with an LT via the miniDSP - but have to be careful with low end boost and cone excursion.
I don't get LT in practice. When modeling LT in winISP you have to reduce power significantly due to cone extension at the boosted frequencies, looking at before and after plots it seems it would be easier to use a shelf filter to bring down the higher frequencies instead of boosting lower. Overall the effect is almost identical if looking at max SPL at a given frequency below the LT boost due to reduced power handeling. Perhaps I am using the modeling incorrectly.
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Report to Moderator - Thread Name Change Request
Suggested new thread title: Lab 12 Based Offset Driver - Mass Loaded - Transmission Line (OD-ML-TL) Design by Bjorno and tb46.
Suggested new thread title: Lab 12 Based Offset Driver - Mass Loaded - Transmission Line (OD-ML-TL) Design by Bjorno and tb46.
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thread tittle changed per request...
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