New project-TL towers, using Bob Brines plans

[GeorgeO]

I have rethought my plans about a layer of ply over the MDF-primarily from a cost perspective, and will do a supra baffle or a full timber baffle-not yet decided, with rounded edges for the sides and rear, having seen and liked a friend's recent efforts on a sub woofer enclosure.

I hope either today or tomorrow to get started on the enclosures, and will go and buy 18 mm MDF and 6mm Bison Board. Need to make a trip to the busy area of SP Road to pick up the MX speaker terminals- a real time consuming exercise!

I also need to check on fibreglass/polyfill batting.Does anyone know if fibreglass acoustic ceiling panels are available here? If yes, what is the size and thickness?

Thanks

George

 

[quad]

I have seen Rockwool tiles, about 1'x1', and 1" thick,
with some AC guys.
Regulars here may already be aware, but just thought
to mention that fibreglass insulation is a pain to handle.
Make sure you wear gloves covering your hands.
Those tiny fibres are really itchy and can cause a rash too.

 

[cmsajith]

Since you are going to sp road for connectors, you can try one shop near to that which supplies GlassWool, one month back i inquired there and he was quoting ~1200 per roll. I dont remember the shop name, but i can locate it. On coming from corporation circle towards kr market, one fly over comes (after the sp road entry). Below that flyover there are some hardware shops, ask them for Acoustic wool / GlassWool. Rigid compressed boards are not available with him. If he doesn't have the material, he will get it from somebody else (on that day he called somebody else also for compressed boards).

I have rethought my plans about a layer of ply over the MDF-primarily from a cost perspective, and will do a supra baffle or a full timber baffle-not yet decided, with rounded edges for the sides and rear, having seen and liked a friend's recent efforts on a sub woofer enclosure.

I hope either today or tomorrow to get started on the enclosures, and will go and buy 18 mm MDF and 6mm Bison Board. Need to make a trip to the busy area of SP Road to pick up the MX speaker terminals- a real time consuming exercise!

I also need to check on fibreglass/polyfill batting.Does anyone know if fibreglass acoustic ceiling panels are available here? If yes, what is the size and thickness?

Thanks

George

 

[GeorgeO]

Got the MDF ( 1 1/2 sheet of 8 X 4 and Bison board (one 8 X 4 sheet) today, as well as the terminals from MX(Thanks Sajith for saving me the SP Road trip!) I plan to get the carpenter to start cutting the MDF and Bison Board according to the layout plan provided, get the fibreglass and then start assembling. I'm hoping that I can get the enclosures completed in 4 days.

I will post a few pics as we go along.

George

 

[GeorgeO]

Progres Report:

Folks

Day 1

We have cut all the MDF( Mangalam brand, actual thickness is 18mm, not 19mm) to size-the front, sides, top, bottom braces and stand. The sides, front and rear have been marked to see where the braces will be seated, and the front has been taken to a local carpentry shop for the round hole for mounting the driver to be neatly seated, as well as for the braces to have the square holes cut neatly. We plan to check on pvc pipe availability to cut the holes for the ports. A friend from out of town has wound the inductors, am arranging for them to be brought across to me.

Plan or Day 2 is to cut the Bison Board pieces and stick it onto the inside of the MDF, and then glue onto it either fibreglass(carefully, using gloves) or polyester. I am also researching the exact outer diameter of the pvc pipe that I will use for the port, so make the hole in the front baffle. The cutout for the terminals will also be one at the rear.

Will post some photographs and post a report tomorrow. In case anyone has any questions about any of the points made above, please ask!


George

 

[GeorgeO]

Was quite busy today so couldnt take any photographs of work in progress-but it is progressing quite well. Both boxes are done , using the MDF, and holes cut for both the driver and the terminals.

Bought the synthetic rubber adhesive-I looked far and wide but just couldnt find Dendrite-but the Fevicol equivalent looks as good.I bought pvc pipe for the port tubes, and will be cutting and sticking the Bison Board pieces on the inner side of th MDF tomorrow. along with the polyester fibre for damping. My jope is to complete the assembly of the boxes by tomorrow evening, and work on the supra baffle and polishing on Thursday.

 

[GeorgeO]

Took some photographs, hoping that I would upload them, but find that my main computer system is down, so I will keep taking the shots and upload them after I am completed.

The status as of today is that the raw mdf boxes have been lined with Bison Board-both sides,and rear. I bought a couple of Reliance pillows for the polyfill(189 each).

Total costs so far:

MDF+ BB Rs 2500 delivered
2 kgs Fevicol(for MDF+ for BB and Poly) 490
Polyester Rs 388
cuttign charges for braces and front baffle-130
PVC pipe for ports Rs 30
MX Terminals Rs 200
Inductors( gifts from a friend who custom wound them for me, otherwise about $20)

Total so far: Rs Rs 3640

Estimated labour charges Rs Rs 2000

Others:

Fostex drivers and Bob Brines plans US $ !70


Tomorrow we will complete gluing the polyester lining and close the enclosure by fixing the pvc ports and gluing on the front baffle after fixing the false baffle.



All in all it will cost around Rs 12-13K.

George

 

[GeorgeO]

After the last post we glued on the BB onto the front, and finished linign all the sides with polyfill, sticking it on with fevicol. Tomorow morning I plan to fix the front, and also the base. The false baffle can easily be made from a template that is providd int h plans-all I need to do is to printout four pages, assemble them together and then trace it out on the MDF and cut it according to the shape. Brines plans are very detailed and well worth the savings in time and effort.

I will power this using a 55wpc AKSA power amp( with Nirvana upgrade), using the Softsqueeze software provided by Slim Devices, which will access audio from my ReadNas.

I may use one of my two pre amps which are gathering dust if I have the place to keep it and in case I need a volume control, havent yet decided. I am also running out of plug points-I have about 8-9 devices already connected in and around my computer!

 

[quad]

George,

Looks like a lot of progress. Eagerly await the
pics.
Do you plan to seal the mdf to prevent water
absorption? If so, what is the product avaialble here?
Have you decided on the finish - veneer or paint?

 

[keith_correa]

After the last post we glued on the BB onto the front, and finished linign all the sides with polyfill, sticking it on with fevicol.

George:

What made you choose/use polyfill over the fibreglass? How did you know how much to use?

 

[GeorgeO]

Have to figure out what to use to polish the MDF-I will decide tomorrow. There is no water/moisture in the area that I plan to use this system. so I am not worried about that.. I am not veneering this system, like I did all of my other systems-this is a "garib rath" trip for me. In the event I want to veneer it I can do it.

I have used fibreglass earlier-it's a lot messier to use than polyester. The instructions are to use "batting"-the pillow stuff is more like cotton, so all I did was take about an inch thickness and stick it on all the layers in as uniform a manner as possible. It may have been better if I was able to source polyester in uniformly thick "batting" medium. but I ran out of patience.

By using BB panels inside it, the cabinet is acoustically fairly dead, if you do a "knuckle" test. It's also now pretty heavy.

George

 

[GeorgeO]

I had second thoughts about using the very loose polyester fibre that I had pulled out of Reliance pillow.Since I wantd to do it as well a I could, I went and bought some of the kind of polyfibre that is used in Rasais(quilts)-this is slightly more layered, sells by the metre, rather than loose (Rs 80).

For polishing the MDF we bought stuff that will give a rosewood type finish. The plan was to use polyurethane to seal it, but since matt finish pu (Touchwood was the brand that we wanted) was not available we will do it later.

George

 

[gobble]

I had second thoughts about using the very loose polyester fibre that I had pulled out of Reliance pillow.Since I wantd to do it as well a I could, I went and bought some of the kind of polyfibre that is used in Rasais(quilts)-this is slightly more layered, sells by the metre, rather than loose (Rs 80).

For polishing the MDF we bought stuff that will give a rosewood type finish. The plan was to use polyurethane to seal it, but since matt finish pu (Touchwood was the brand that we wanted) was not available we will do it later.

George

I wanted to find out when I was building my AV rack - is there a way to emboss patterns on MDF then give it a light wood varnish type finish with the patterns visible?

Regards

 

[gobble]

Just found these

Wood Graining Tools
How To Paint a Faux Wood Grain : How-To : DIY Network
How to Create Faux Wood Grain With a Faux Wood Graining Tool

Cheers

 

[aks07]

Hi George

Another great project shaping up well !

1. MDF is very difficult to polish. You can maybe spry paint it after primer coating. But I doubt how long will that hold up before cracking. The best (and expensive!) solution still is veneer and then polish.

2. Racron (pillow filling) wont work. Get the thermal wool that air conditioning guys use. Its like a mattress. One of such should cost about Rs. 600. That is what I paid when doing up the Lambda Acoustic Subwoofer.

3. What was the board thickness specified in the BB plan. The usual MDF found in India is 18mm and 14mm.

 

[GeorgeO]

Hi Ashok

Thanks for the input.

I got 18mm(Mangalam)+ 6m Bison Board, an for the inside the spec is for fibreglass, which I felt was quite messy to work with( I used it for stuffing one stand mounted monitor as well as for my 84 lt Lambda subwoofer box). I initially used pillow polyfill which was not looking good, then after mulling over it last night, I picked up a metre of sheetlike polyfill and it is already completed, and the front sealed this evening.

I will post some pictures soon s I can-my main system has a motherboard problem so I cant download the images until that is up and running.I am taking my chances with polish-I have the option of applying veneer at a later stage should I want to-or after the polish starts to crack up!

Our friend in Gurgaon has wound a 1.5 mH inductor for me last weekend which a mule is bringing to Bangalore-hopefully tonight- so Inshallah the system will be up and running very soon. I am sending you an email to your gmail account, please check it a little later.

Regards
George

 

[suri]

Hi George

Another great project shaping up well !

1. MDF is very difficult to polish. You can maybe spry paint it after primer coating. But I doubt how long will that hold up before cracking. The best (and expensive!) solution still is veneer and then polish.

hI aks07,

ihave worked extensively with MDF and -

1. - MDF should never be used untreated in the tropics - all types of saprophytes (fungus) will degrade untreated MDF

2. treatment = sanding sealer and nitrocellulose lacquer (at least 6 coats with the base two coats of colour of choice.

3. cracks show up in time but N.C. lacquer allows MDF to breathe and that is a good thing

4. primer and automotive finish on MDF give a long-lasting premium finish
but the resultant SQ is harsh. Cracks do not develop on thusly finished MDF and the finish is superior to N.C. lacquer finished MDF, but SQ suffers


@George = take heed!

 

[GeorgeO]

Hi Suri

I have planned to use veneer sometime in the not too distant future. The raw MDF carcass will do for now-the marginal extra cost for veneering at that time wont hurt-but it definitely is a factor at this time.

I am using a sanding sealer, and some other things tomorrow..

George

hI aks07,

ihave worked extensively with MDF and -

1. - MDF should never be used untreated in the tropics - all types of saprophytes (fungus) will degrade untreated MDF

2. treatment = sanding sealer and nitrocellulose lacquer (at least 6 coats with the base two coats of colour of choice.

3. cracks show up in time but N.C. lacquer allows MDF to breathe and that is a good thing

4. primer and automotive finish on MDF give a long-lasting premium finish
but the resultant SQ is harsh. Cracks do not develop on thusly finished MDF and the finish is superior to N.C. lacquer finished MDF, but SQ suffers


@George = take heed!

 

[GeorgeO]

Update Day 5

Got the false baffle and stands ready, picked up eight black Allen screws for mounting the driver, along with threaded inserts( from a friend, who also gave me some gasket tape to ensure and airtight fit for the driver).

Got the 1.5mH inductors in hand via a mule( a nephew actually!) who came from Delhi this morning, and door delivered it at 7.30 PM, sanded and polished the enclosures-first coat. Tomorrow I have to go to SP Road and pick up the wire wound inductors and will solder the internal wires to the driver and the terminal after connecting the baffle step compensation filter.

Hope to play music by early afternoon. I will take pictures of it tomorrow just prior to final assembly.

Have a guest( the buddy who brought my Fostex drivers last month from the US) coming in tonight, and spending the night with me, enroute to Atlanta tomorrow morning, so some Single Malt will be imbibed to relax after a hard week's work!

Cheers

George

 

[keith_correa]

Update Day 5

Got the false baffle and stands ready, picked up eight black Allen screws for mounting the driver, along with threaded inserts( from a friend, who also gave me some gasket tape to ensure and airtight fit for the driver).

Got the 1.5mH inductors in hand via a mule( a nephew actually!) who came from Delhi this morning, and door delivered it at 7.30 PM, sanded and polished the enclosures-first coat. Tomorrow I have to go to SP Road and pick up the wire wound inductors and will solder the internal wires to the driver and the terminal after connecting the baffle step compensation filter.

Hope to play music by early afternoon. I will take pictures of it tomorrow just prior to final assembly.

Have a guest( the buddy who brought my Fostex drivers last month from the US) coming in tonight, and spending the night with me, enroute to Atlanta tomorrow morning, so some Single Malt will be imbibed to relax after a hard week's work!

Cheers

George

Oh, man - wouldn't I love the "hard work" that you did? Instead I'm stuck at my horrible job - which is nothing but a hyped up clerical position. The moolah is very good though
Early retirement - where art thou?