CT 142 Transmissionline speaker (photo's)

[Delatorious]

Hi,

I built the CT 142 from visaton.

unfortunatly there was too much light my K750I could handle

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As you can see I sanded the metal side of the speaker, afther that i treateded with lacquer so it won't oxidate

The tweeter is from Vifa, titanium dome, it sounds really nice!

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The case is built from MDF after that i putted 5.5 mm Meranti triplex on the sides, the corners are 'vuren' wood, and treated it with lacquer.

Feedback is welcome.

Niels

[Frankynstone]

Hi Niels,

I like the old-fashioned style of the dark wooden boxes and the idea to make the metal shiny is realy nice.

Somehow I can't imagine that the clumsy W170S and a metal tweeter give a harmonic sound. How complex is the crossover and what crossover frequency is used? I don't know this cheap trick.

Please, write some more about the sound of your new speakers. Seem to be interesting.

Frank.

[doctrin]

I like the Transmission and the guys which use this old complicate bass extension

yeah and write something about the sound!!!

regards

[Ronkel]

Hi Niels,

Very nice how you've given those speakers a somewhat classical look . Personally they remind me a bit of speakers from the 80's with that typical wooden finish. I also like the way you've treated the woofers, really works out great ! It's not all that modern, but they truly have their own style. Keep up the good work!

P.S. You haven't sanded ("gezandstraald?") the faceplate of the tweeter, have you? Maybe that would be nice, too.

[Delatorious]

Hello

@ Frankynstone and Doctrin.

The High tones are perfect, I havend found any strange frequencies.
The (sub)low part is really impressive, 30-45 hz is just awesome
You really feel the pressure on your ears on low frequencies!

One of the first things I noticed about the sound was that I mis a 'kickbase' like drums, that is really bad. at that frequency you can really hear that the speakers membrane is made from paper, it just sounds awefull.

There for I am going to make two other small front speakers in the same style and the same serie driver (w130S/8) in order to fill up the dip in the sound.
I haven't really figured yet witch case-princip TL will fit. Although i'm thinking about Br.

any suggestions?

although I really recommend building this project!

Niels (19 Years old)

P.s. The tweaters frontplate is made from plasic, so I can't sandblast it, too bad:P

[doctrin]

I don`t think blaming the paper cone is the right idea...i think its more the transmission line bass dale/valley/frequency hole, call it like you want. I think it could sound better with an helmholtz absorber HHA...but its just a guess

[Delatorious]

Original geschrieben von doctrin
I don`t think blaming the paper cone is the right idea...i think its more the transmission line bass dale/valley/frequency hole, call it like you want. I think it could sound better with an helmholtz absorber HHA...but its just a guess

I already noticed I putted to less damping in the case, therefore I ordered some polyesterwool to put behind the drivers, in the TL port I will put Pritex.
Someone told me that polyester wool is better for damping high tones, and Pritex is better to get the peaks out of the low frequencies.

That same person also told me that it's a typical complain of TL, so the next TL project will be 3-way. the woofer wil be cut off @ 50 Hz

Niels

(p.s.) I used a standard 2-way crossover, I'm not good with calculating filters and I couldn't find a crossover from my VIFA tweeter

[doctrin]

Cutting @ 50Hz is realy unusal ....there are 2 types of TL which don`t make trouble like this -> 2 woofers each positioned in 1/3 and 1/5 of line length
or this
HHA (little Bassreflexchambers to absorb the resonances)
I recommend this two types because of lesser use of damping material and nearly no resonances.
Especially if you use both types.


MfG

[doctrin]

really funny is the fact that visaton built the topas without the HHA and its working

[Frankynstone]

If the woofer does not reproduce the true colors of sound then the problem is to be found in the midrange. A large diaphragm can't follow the fast signals accurately.

What do you mean by "standard 2-way crossover"? Is it such a all-purpose or general-purpose thing which is not designed for your speakers but to work anyhow?

The bass response depends on how woofer and transmission line work together. If the bass isn't kicking but soft and with (too much) warmth you might have to kill low frequency resonances in the line (and may be in your room, too).

[Delatorious]

Original geschrieben von Frankynstone
If the woofer does not reproduce the true colors of sound then the problem is to be found in the midrange. A large diaphragm can't follow the fast signals accurately.

What do you mean by "standard 2-way crossover"? Is it such a all-purpose or general-purpose thing which is not designed for your speakers but to work anyhow?

The bass response depends on how woofer and transmission line work together. If the bass isn't kicking but soft and with (too much) warmth you might have to kill low frequency resonances in the line (and may be in your room, too).

Yes that's right,

Indeed it's a cheap crossover, witch i want to change, certainly from the tweeter.

it is indeed not kickin' but aweful low. I will put more damping in the case, that should help it get less low.

If that doesn't work, what posibillities do I have, to change the sound?

[doctrin]

with the finished construction? nearly nothing

[Frankynstone]

You can try to simulate the crossover in BoxSim. Use DSM 25 FFL instead of your tweeter or try to make a chassis file for your tweeter by measurement or the date provided by a magazine. Then you can optimize th crossover.

Or find someone to analyze the chassis in the box and simulate a crossover in WinBoxSimu. This is gives quite realistic results.

Trial and error may also be successful or result in a desaster.

[doctrin]

But the crossover isn`t produceing kick bass, i thought that`s what he`s missing?

regards

[Delatorious]

Indeed the kickbase is what I miss, I don't really think that's the blame of the crossover. I't just the TL to blame and because I didn't use a helmholz absorber

Because I can't change anything but the damping, I think it's best to build another pair of speakers to compensate. The problem i'm confronting now is what kind of case princip to use. I'm really thinking of the w 130 s. I'm thinking of a Bandpass princip (Alto genesis sub) with a tweeter in it.
A college of mine has build this, but he said the bass is really bad then you aim the bassport downwards.
Maybe Bassreflex is the easyest...

Niels