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Baobab's respected R50's Hmmm
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AndyS
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Joined: 15 Apr 2013
Posts: 38
Location: North Derbyshire

PostPosted: Sun Jul 07, 2013 8:31 pm    Post subject: Reply with quote

proffski wrote:
AndyS wrote:
I was initially trying to get the newer type T27, I have a dead pair and the older ones seemed to be a better fit. As the B139s were the original Racetrack type it was possible that the T27s were the older type. Not sure whether the sound would be much different? I have a pair of Morel CAT 298 Tweeters which are recommended by Falcon and the mounting holes are identical so I might try those at some point. If I can get a pair of the later T27s at a reasonable price I will try them, I also have a slightly later pair of B110s still SP1033s but originally black and a later pair of 139s so may be worth learning how to use a router.
At the moment the bass is a bit loose at times, never sure that is the recording or speaker, any ideas on whether I should add or take away the long haired wool from the bass chamber?


The earlier T27s had a lower fs of 900Hz if my memory serves me correctly. The last version was 1,200Hz.


Still not very tech, so is there any clear thought on which is better, will it be worth the expense, what is your opinion, if you have one, about the Morels?
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TL 200
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Location: Emmer-Compascuum The Netherlands

PostPosted: Mon Jul 08, 2013 9:08 am    Post subject: Reply with quote

AndyS wrote:
TL 200 wrote:
Did you use the original fillings at the right places?
The white cloth stapled behind the B139 isn't there originally.
Perhaps it's better to remove it, might influence the speaker. Prevents it from a full swing.
Succes. TL.


The original filling was not there, there was some wool but also some blocks from some B&W speakers. The original speakers has a sheet of foam between the baffle and cabinet, see early pics, used probably to keep the wool from the speaker backs. The material is this voile type stuff and easily as open as the foam.

Seems you have to re-tune the labyrinth to get them working properly.
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speakerguru
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Joined: 18 Nov 2005
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Location: Green Hut, Tovil

PostPosted: Mon Jul 08, 2013 3:56 pm    Post subject: Reply with quote

TL 200 wrote:

Seems you have to re-tune the labyrinth to get them working properly.

If you have to "tune" the labyrinth then it is not a labyrinth nor a transmission line.

It is a "pipe" (as in organ pipe).
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proffski
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Joined: 22 Aug 2003
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Location: Tewkesbury UK

PostPosted: Mon Jul 08, 2013 5:33 pm    Post subject: Reply with quote

speakerguru wrote:
TL 200 wrote:

Seems you have to re-tune the labyrinth to get them working properly.
If you have to "tune" the labyrinth then it is not a labyrinth nor a transmission line. It is a "pipe" (as in organ pipe).


So true, and pipes will have standing waves...
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TL 200
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Joined: 27 Jul 2009
Posts: 141
Location: Emmer-Compascuum The Netherlands

PostPosted: Mon Jul 08, 2013 7:03 pm    Post subject: Reply with quote

speakerguru wrote:
TL 200 wrote:

Seems you have to re-tune the labyrinth to get them working properly.

If you have to "tune" the labyrinth then it is not a labyrinth nor a transmission line.

It is a "pipe" (as in organ pipe).


Please excuse me for using the wrong word, i'm dutch and it's because the pipe is folded, i thought it's called a labyrinth. Embarassed
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TL 200
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Joined: 27 Jul 2009
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Location: Emmer-Compascuum The Netherlands

PostPosted: Mon Jul 08, 2013 7:14 pm    Post subject: Reply with quote

proffski wrote:
speakerguru wrote:
TL 200 wrote:

Seems you have to re-tune the labyrinth to get them working properly.
If you have to "tune" the labyrinth then it is not a labyrinth nor a transmission line. It is a "pipe" (as in organ pipe).


So true, and pipes will have standing waves...


I meant that the pipe has to stuffed at the right places to tune it to the resonance frequency of the B139. The stuffing has to be just right to make the pipe (virtually) a quarter wavelength long. that's also why the pipe gets narrower to the end. I guess you know what i mean Proffski, you're a clever guy. Wink
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proffski
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Joined: 22 Aug 2003
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PostPosted: Mon Jul 08, 2013 7:19 pm    Post subject: Reply with quote

I once very foolishly built a half wavelength device. It took weeks and weeks of playing around with the contents to stop it "hooting" at some frequencies. All explained if you click underneath some of the pictures.
Feel free to browse.
Link: http://s891.photobucket.com/user/AndyGoloskof/library/?sort=6&page=1#/user/AndyGoloskof/library/?sort=6&page=2&_suid=1373307624668018932157912619585
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I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
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TL 200
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Joined: 27 Jul 2009
Posts: 141
Location: Emmer-Compascuum The Netherlands

PostPosted: Tue Jul 09, 2013 9:26 am    Post subject: Reply with quote

proffski wrote:
I once very foolishly built a half wavelength device. It took weeks and weeks of playing around with the contents to stop it "hooting" at some frequencies. All explained if you click underneath some of the pictures.
Feel free to browse.
Link: http://s891.photobucket.com/user/AndyGoloskof/library/?sort=6&page=1#/user/AndyGoloskof/library/?sort=6&page=2&_suid=1373307624668018932157912619585


Never said it was easy Proffski, it took Cambridge Audio 6 years to design the R50's TL 200's.
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The Twilight of the Idols, 1889
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AndyS
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Joined: 15 Apr 2013
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Location: North Derbyshire

PostPosted: Tue Jul 30, 2013 12:20 pm    Post subject: Reply with quote

Do you, anyone, have suggestions on the amount of longhaired wool required and even a suitable piece of music with a good low frequency spread to use.
As the cabinets were made by a third party and the line was lined with a thin foam it seems that only the bass chamber and end of the line that could be filled. The original DIY article had the line filled before the final side panel was fitted.

I have just discovered that the best time to buy speaker units from ebay is in a heatwave, a pair of later style T27s for £35, my son also noticed that the price of fishing gear went up![/quote]
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proffski
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Joined: 22 Aug 2003
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Location: Tewkesbury UK

PostPosted: Tue Jul 30, 2013 12:24 pm    Post subject: Reply with quote

I did mine by listening to organ music and swept tones from 15Hz to 100Hz. Spent days on it!!! In the end did it in the garden as at times the room and suspended floor joined in... Sad
Here is a good guide: http://documents.jordan-usa.com/Famous-Articles/Bailey-1972-Transmission-Line-Loudspeaker-Enclosure.pdf

And: http://www.t-linespeakers.org/design/classic.html
as well as: http://www.kt.agh.edu.pl/~natkanie/papers/TLS.pdf
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