This might be madness but I'm going to attempt an ultra-thin walled transmission line, with a full range driver and on a tiny scale. I'm expecting some resonances and some long delays, but with the inherent bracing of the transmission line, plus some damping material, as well as the fact that the panels are each very small, I don't think this will be as huge of a problem as it may seem at first glance. Has anyone ever made speakers with 6mm material? I have read that some of the BBC designs used 8mm... I based this on scaling down existing designs, and haven't run my design through a simulator so please feel free to advise me/roast me as you see fit. If anyone fancied simulating my design for me that would be swell.
CHN-50: FS 113.1594 HzVAS 1.0965 LRE 3.4000 OhmQMS 2.8318QES 0.6865QTS 0.5526B×l 2.6869 T×mSPL 85.74SD 0.0028 m2CMS 0.9822 mm/NMMS 2.0871 gRMS 0.5148 WMRAT 329987 WARMT 2.6380 WMMMD 2.0020 gh0 0.21%L1kHz0.0600 mHPWR 7 watts (Nom)X MAX (Mech) +/- 3.5mm
CHN-50: FS 113.1594 HzVAS 1.0965 LRE 3.4000 OhmQMS 2.8318QES 0.6865QTS 0.5526B×l 2.6869 T×mSPL 85.74SD 0.0028 m2CMS 0.9822 mm/NMMS 2.0871 gRMS 0.5148 WMRAT 329987 WARMT 2.6380 WMMMD 2.0020 gh0 0.21%L1kHz0.0600 mHPWR 7 watts (Nom)X MAX (Mech) +/- 3.5mm
EDIT: The design doesn't show measurements, so for reference the TL goes 93 mm behind the driver, to 36 mm, to 15 mm, to 6 mm
More specific? Stainless? Balsa? Paper? Plastic? Snap together Flooring? Masonite? Foamcore?
Your slot at the bottom will probably be very lossy. A round vent with similar cross section in that position might perform better.
6 mm birch plywood with a high layer count - often sold as airplane plywood - will surely be stable enough for this size driver and enclosure.
There’s special versions for lasercutting - different glues for the layers.
6 mm birch plywood with a high layer count - often sold as airplane plywood - will surely be stable enough for this size driver and enclosure.
There’s special versions for lasercutting - different glues for the layers.
For portable enclosures 3/4 ply is the normal. The whole "light" craze people broke tradition and started using thin stuff for weight reduction.
The point?
Going to something thin 6mm, your issue will be the joints not much material to glue too.
This is why I brought up the portable cabs. They had same problems, less joint area. Rattles are fixed with bracing.
How you can brace a long line so it aint a rattle box, up to your creativity.
If it doesnt rattle the cabinet will still have loses to ringing.
Far as small drivers and trying to weasel bass out of them. Not into it. 60 to 80 Hz Fs will be just that, they end.
Dont care for long fart tubes. Almost insulting to some because the learning process and design time is extended for TL design.
Certain amount of pride I guess. Been there
8" driver with low Qts will likely fit in the same volume. No resonate tube , TL is reflex that is too big and too long.
Way to many correction factors to make it work. More suitable for crossovers below 100 Hz.
Typical reflex should have One small resonance closer to 600 Hz or Higher. More suitable and will actually do 50 to 40 Hz
Transient can be good because many 8" go down to 30 Hz Fs. So less port more real cone movement. Same box volume
The point?
Going to something thin 6mm, your issue will be the joints not much material to glue too.
This is why I brought up the portable cabs. They had same problems, less joint area. Rattles are fixed with bracing.
How you can brace a long line so it aint a rattle box, up to your creativity.
If it doesnt rattle the cabinet will still have loses to ringing.
Far as small drivers and trying to weasel bass out of them. Not into it. 60 to 80 Hz Fs will be just that, they end.
Dont care for long fart tubes. Almost insulting to some because the learning process and design time is extended for TL design.
Certain amount of pride I guess. Been there
8" driver with low Qts will likely fit in the same volume. No resonate tube , TL is reflex that is too big and too long.
Way to many correction factors to make it work. More suitable for crossovers below 100 Hz.
Typical reflex should have One small resonance closer to 600 Hz or Higher. More suitable and will actually do 50 to 40 Hz
Transient can be good because many 8" go down to 30 Hz Fs. So less port more real cone movement. Same box volume
Not the best way forward IMHO, but that's just my 2 cents, or tuppence I guess in your case. 😉
jeff
Bud,
Have you modeled this?
Check out the Woden Bloodhound BabyLab and Giraffe for reference.
http://wodendesign.com/downloads/Woden-BabyLabs-241018.pdf
http://wodendesign.com/downloads/Giraffe-A52-MLTL-0v99-081015.pdf
dave
Have you modeled this?
Check out the Woden Bloodhound BabyLab and Giraffe for reference.
http://wodendesign.com/downloads/Woden-BabyLabs-241018.pdf
http://wodendesign.com/downloads/Giraffe-A52-MLTL-0v99-081015.pdf
dave
Given the short length, the R in is the vent may well help push the box aperiodic. This would most likely be classed as an ML-TL.
Possibly. Thinner Al or steel would work. In any case, i would liely add more bracing if plywood.
dave
Maybe Scott could do a BabyLab for the CHN-50, cause we know he doesn't have enough to do already. 😉
jeff
I did something similar based on Scottmoose’s Lance TL but with less of a tight taper - too narrow and long of an exit might excite a resonance like a brass instrument - sort of a honk sound so be careful with long narrow passages. I used an RS100-4 3.5in driver.
There is a Labyrinth for Chn50 by Scott.
Post in thread 'Miscellaneous designs - Markaudio, Fostex, TB, Dayton, SEAS etc'
The pressure of the fundamental is highest at the start of the pipe and lowest at the opening so stop vibrations at the driver is important. Use constrained layer damping between the two parts of the front baffle. Perhaps some thin braces 6 and 12 a clock from the front to the first baffle.
Thanks for the reminder. I would just build that, as Scott's done all the heavy lifting. And out of 12mm Baltic Birch. 👍
jeff
Thanks for all this everyone, really useful information. The designs mentioned above seem to have the slot at the back but I want mine at the front, I might have another go and post a new version.