LGK 2.0 TL design

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Danny Richie

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Re: LGK 2.0 TL design
« Reply #20 on: 22 Nov 2022, 09:39 pm »
Do you have a picture Danny.

I do have some measurements that show difference, bu tAFAIC it is open to interpretation.

I strongly sispect that what you measured is not what EnABL does.

dave

It has been a while but there was a whole thread on it: https://www.audiocircle.com/index.php?topic=59575.msg530093#msg530093

I found zero difference measured in any way. I still have the woofers sitting around in here too.

The dots or dashes did little more than color the cone. There was not enough mass there to do anything and while the pattern looked cool it was not where any real cone damping needed to be.

There is also FAR greater differences in compliance and damping from burning the driver in than what effect any of this might have.

Martin Garrish

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Re: LGK 2.0 TL design
« Reply #21 on: 22 Nov 2022, 10:29 pm »
Danny, you really should try silicone fluid doping of FR drivers just once to see what you thinks...

I used to get my silicone fluid (or oil) from Ambersil, but they don't stock it any more. 5 minutes googling finds these guys in the UK, and i'd be astonished if it wasn't as easy to find in Texas. http://www.allcocks.co.uk/en/products/silicones/fluids.htm

It's completely non toxic, does not harm the environment, and does not cause degradation over time. I found 60 cSt (centistokes) worked well for my soft FR paper cones, but try higher viscosities. I treated some drivers recently: just put drivers on table, paint silicone fluid on cone nice and thick, let soak into the fibres overnight then turn driver upside down and drain. Even though the silicone fluid soaks in, I normally coat both sides to be thorough. The drivers weep for about a week if you fit them immediately but it causes no harm to veneer or electronics and just wipes off. Take a waterfall plot before and after and you'll see what I mean about smoother response...

Mart
« Last Edit: 23 Nov 2022, 11:00 am by Martin Garrish »

Martin Garrish

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Re: LGK 2.0 TL design
« Reply #22 on: 4 Dec 2022, 09:32 pm »
I've had one last go at designing a compact transmission line speaker around the LGK 2.0 driver. My objective was to understand CTL design rules for another project. At the same time I saw an opportunity to improve the power handling and bass with the LGK 2.0 TL project. This time I've got all dimensions below the LGK 2.1 speaker to fit into LGK family. This speaker is aimed at FR purists like myself.

I'm still favouring the 1/4 wave aperiodic tuning of 0.75 octaves below driver Fs=113Hz, although this does produce a 6th order roll-off below 60Hz. I'm assuming stuffing as acoustic suspension cabinet up to halfway between "S3" to "S4" in section shown. I've decided to leave in the corner pieces to make sure the tuning works as predicted, although as many parts as possible have been commonised to keep machining costs down. The 3/4 wave is still handled by driver positioning, and 5/4 wave is still handled by line depth 1/4 wave decoupling at 675Hz. Hornresp is a 1D solver, so will over-predict higher frequency resonances.

As to the logistics of getting a pair built and tested then the problem is that I'm based in the UK. So as I see it options are:
1. Order LGK 2.0 parts without cabinet then get the cabinet made locally. If I do that then I may as well just update measurement tool from Liberty Audiosuite.
2. Pay for Denton woodworks to build a pair of walnut veneer cabs and assemble speaker for Danny to test.
3. Find a guinea-pig closer to GR-Research to build and then keep the speakers. I still get useful CTL experience, although it would be nice to have a pair to evaluate how good the CTL design actually is.

Any thoughts?  :?

Mart













Driver displacement with 1 watt input.


TL port velocity at maximum driver power.

« Last Edit: 5 Dec 2022, 10:24 am by Martin Garrish »