Looking for a little advice re : TLb 'tizzy' midrange

[Forster]

Hello,

A while ago I built a pair of TLB Transmission line speakers whose design is offered on the Planet 10 website. These speakers are part of one of my systems.

A superb design, but with one issue, at least for myself. There is a ragged edge in the upper reaches of the midrange, especially noted with vocals. One that has made me wonder if a change of tweeter, or an upgraded cap might deal with.

The system is : Sansui SR 838 turntable, Nakamichi CA 5 preamp, Onkyo M 504 main amp, Technics SL p1300 Broadcast CD player, Nakamichi CR 7A tape deck.

At first I thought the CD laser might be failing, but the sound through the headphones is free of the sibilance. The sound from LP and tape deck is also free of this harshness.

Any thoughts?

Thanks in advance - Forster

[BudP]

Forster,

For a fairly easy but somewhat radical upgrade to the drivers themselves read this thread.

Help me kill a fostex artifact.

There are others here on DIY that are experimenting with what ultrakaz describes and I show pictures of. This might well take care of all of your concerns, except what else to upgrade....

Bud

[Forster]

Thanks BudP,

I will check this thread. The issue with the TLb is that it calls for the two midrange speakers to be epoxied together with a suspension bar at the magnets, so I will not be able to access them.

I have tried various equipment interchanges, Heybrook TTII with Hadcock & Shure v154, nad phono amp, Kinergetics 500 power amp, Kinergetics c800 preamp, and Creek CD42 CD player.

I supposed that the Nakamichi CA5 was introducing the 'tizz' as I did not want to face the fact that my beautiful speakers were at fault, but it seems not.

Best regards - Forster

[BudP]

Forster,

Mine was a generic reply.

What is a TLB?

Why does glue across a bar between the magnets make the driver faces not available?

If you can get to the faces you can a least put an EnABL process on, just not the other half, the Mamboni effectors.

Is there a link with pics?

Bud

[Forster]

Hello Bud,

Sorry for the ambiguity.

This is the design :

http://www.t-linespeakers.org/projects/tlB/index.html

One of the sweetest pair of speakers I have ever built.

You will see on the construction page that the speakers are epoxied to one another internally, magnet to magnet via a spacer.

Best regards - Forster

[BudP]

Forster,

Nothing to be sorry for. Just sad that they have a blemish at all. I did not look deeply into the design page yet and will not be able to until this evening. Do look at the link I showed and perhaps go to this link and look at the last portions, with CSD pics of a cone tweeter.

http://www.positive-feedback.com/Iss...ndingwaves.htm

The kind of "fill" smoothing you see, with some 9 dB fills, is what you can expect from front only treated drivers. About 70% of all possible benefit can be obtained from one side treatment, and that is more often than not enough. The real benefit comes from what you see in the last comparison, the loss of ringing modes, a very typical cause of harshness and peaked response in any type of driver.

What I will be fishing for later tonight is type of tweeter and crossover point and type.

Bud