Small Thor ML-TL Transmissionline speaker project

[Anil kumar]

I was really inspired by the thread at diy audio.com on Seas Thors. Thor was designed by D'Appolito based on Augspurger's work. Thor uses very expensive Seas drivers like W18E001 woofers and T25CF002 "MILLENNIUM" tweeter mounted in a D'Appolito configuration. These drivers are beyond my budget & reach. So here in this experiment, the idea here is to build a similar TL based on the budget minded drivers. Here i am using locally procured driverse & xover bought from Sreekanth sometimeback. On testing these mid bass, the sound qualty was much better than a Vifa (exceptional mid range quality) so thanks to sreekanth for excellent quality drivers.
But this design may not sound like Thors, but definately sounds much better than a 30K bass reflex speaker. Dave of Planet 10 has custom design on Fat & a Short THOR equivalent for VIFA P17 drivers.

In this modified design there is a solid brace behind the driver ( Mid-woofer magnets should fit tightly to notch) this transfer & distribute the energy from the driver to the back of the cabinet & the other one runs parallel with the baffle notch. Brace needs to be filled with random holes. It has 4" long & 3 " dia port at the back. I am building this for a cousin of mine here in Bengaluru. I started off with the project yesterday, here are some progress pictures.

From the drawing board

Front baffle is doubled by sandwitching two 19mm MDF boards

MY DIY PAGE

 

[asliarun]

Hi Anil,

Thanks for sharing. Your design looks quite cool! I'm keenly following your thread as I plan to go the DIY route as well (have recently purchased a pair of Fostex FX120, and plan to build a simple 10 liter bass reflex). I'm a complete newbie in DIY so I think I will learn a lot from your progress!

The driver brace you are using is a very neat design.. I've seen them in the Fonkens as well.

All the best!

 

[GeorgeO]

Great going..I have 2 D'Appolito designs, the AriaR and the Audax HT speakers. Another speaker system has braces, those these 2 dont.

George

 

[Anil kumar]

Thanks Arun & George for the comment.

FX120 can be used in a wide variety of enclosures, but is best suited to bass reflex, Transmission Line and Quarter Wavelength enclosures. All the best for your project.

I made little progress last week......

Marking for driver cutouts

 

[denom]

Great going Anil,

pls keep us informed of the progress step by step as you have done so uptil now, there are many of us who are eagerly awaiting the next steps, keep it up!

 

[gobble]

Anil

How did you cut those large circles? What drill bit did you use? Hole saw? Whats the diameter of the large holes?

Regards

 

[Anil kumar]

Hi Rahul, i used a jigsaw cutter to make those large circlar holes. Made a 8mm drill close to the inside of the circle, insert the jigsaw, started cutting along the line. Diameter of the cut out is 5.5 inch. I will counter sink the drivers using a circular router.


Regards,
Anil

Anil

How did you cut those large circles? What drill bit did you use? Hole saw? Whats the diameter of the large holes?

Regards

 

[gobble]

Hi Rahul, i used a jigsaw cutter to make those large circlar holes. Made a 8mm drill close to the inside of the circle, insert the jigsaw, started cutting along the line. Diameter of the cut out is 5.5 inch. I will counter sink the drivers using a circular router.


Regards,
Anil

Anil
Do you own a jigsaw? I recently did some sample wood cutting and had a tough time finding somebody with a plain Jigsaw!! Took me a few weeks to locate one actually!! But I didnt know one can cut circles so well with it. I had straight lines cut


Regards

 

[suri]

MY DIY PAGE

hi anil, very interesting for me to see this work in progress!

re the spreading of fevicol- the correct technique is

By witchesofsound at 2009-11-19

to use a piece of formica with teeth cut in the spreading edge -

thus, when the surfaces are pressed together the fevicol has space to spread- and one can save lots of fevicol this way-

otherwise - lots of fevicol is squeezed out when the boards are pressed together.

regds suri

edit - also - scoring of the surfaces to be mated (as in the picture above) increases surfaces area and increases the strength of the bond

 

[Anil kumar]

Do you own a jig saw?

Yes, i do own a jig saw & circular cutter, they are very handy in DIY work.

Thanks to Suri for valuable info.


Regards,
Anil

 

[thekinge]

Hi Anil,

Good going! Threads like this one and suri's "All the speakers I made" tempt me to get into the DIY route in the future - only if I had paid attention to physics classes in school and electrical engineering classes in college:sad:

Do keep us regularly updated with your progress and post as much pictures as possible!

Regards,
thekinge

 

[Anil kumar]

Made some progress on Saturday........

Marking for countersink holes

Ready for router work

countersink holes done

 

[gobble]

Looking good!! what do you plan for the outer finish btw?

Regards

 

[Anil kumar]

Hi Rahul, i am planning to veneer all sides, but still lot of work to be done. I am adapting a new spike design made of MS & Aluminium. Bracing behind the drivers are not yet done, i shall update with more pictures soon.


Regards,
Anil


MY FIRST DIY SPEAKERS

Brace marked to cut 3" holes​

Looking good!! what do you plan for the outer finish btw?

Regards

 

[denom]

These would look good in a rosewood finish.... great job Anil, hope you get time to complete them soon.

 

[Anil kumar]

Hi, my choice is between Cherry or Red Oak. Mahogany finish also looks good.


Anil




My first DIY floorstanders

These would look good in a rosewood finish.... great job Anil, hope you get time to complete them soon.

 

[sud98]

Looks nice. TL based speakers seem to be the 'in' thing, I should listen to one of these to understand the difference.

Do keep a track of your labour hours and costs in an excel spreadsheet, I guess it will be useful if you want to later want to commercialize the same.

Best of Luck on your project.

 

[vivek.saikia]

Great DIY thread there. I really enjoy watching all the DIY contruction pictures. Please let the pictures keep coming in, in abundance.
It reminded me of a subwoofer which I had constructed (or rather directed and designed). I had used 3/4 inch MDF board. The driver was a Sony car woofer and the amp was a Sony car amplifier in the bridged mode with LPF set at 80hz. Luckily, the labour and material charge came out to be zero for me as my dad is a builder. Sad that now stay away from my home town, earning my bread. Such DIY projects are not practical anymore for me.

 

[Anil kumar]

Thanks sud & vivek.
Made some progress yesterday. Cabinet is almost complete.

 

[rallynut]

wow anil,great goin!!!those drivers are very familiar indeed hyeah:!!!!am sure they will turn out beautiful,securamente!!!my exposure to DIY has been very limited,but the relative impact it has had on me..immeasureable.kudos and cheers