Indian equivalents of the following DIY items.

[navin]

yup he calls me nain and you Mr! ha ha ha see how you intimidate people :-) ha ha ha

BTW why MDF. marine ply is just as good if not better.

[Doug]

>>And Sai, there is no Mr. in diyaudio.com<<

See !!! I told you on my email you would get in trouble calling people Mister

Besides, it makes us all feel old

Doug

[Doug]

Here is an interresting link for MDF

http://www.lungster.com/l/speakers/mdffaq/mdf.html#Q5

Doug

[ssSai]

Well the Subject title tells it all.

And, Hello Doug, good to hear from you LIVE at last.

[ashok]

Sai,
The MDF sheets that I bought had MDF stamped in blue ink on the board. I think it was Nuwood. In any case , unlike particle boards you cannot see large wood particles in MDF. There is a softer board available that initially looks deceptively like MDF. It is no good and powders easily. Make sure you get the right thing.
I am surprised that your supplier did not know what MDF is. Really strange.
Cheers.

[ajju]

"I also was fooling around with a software called 3dMax. I tried to visualize my subwoofer. Any criticisms."

sai..
the visualisation looks good...! just a suggestion...Why dont u try making the sub enclosure as just a cube and try putting a heavy piece of tinted glass or something on Top!

What driver do u plan to use ...?
Is the design sealed or ported...?

[ajju]

Acoustic Absorbant:

I had once used coir in one of my speakers...I dint find it as effective as the racron fiberfill stuff. My guess is, the absorption is less because the fibres are a lot thicker or the absorption isnt uniform because its a natural fibre and might have some kind of a regular pattern. Also coir had a tendency to settle, that is it loses its 'flufiness'. In addition absorbs moisture. Result was fungii...
On the other hand, racron does not absorb moisture nor does it settle down easily... but to have a good absorption u need to have a high density of material...loose bunches of these does not produce enough LF attenuation...I learnt this when i was experimenting on a simple transmission line which finally ended up as a set of cheap dorm speakers.(What you see in picture are those common pioneer car speakers. They sounded horrible compared to the jbl's i've put in now) For a volume of approximately 4.7 litres i had to use almost 1/2 the stuff from a regular sized pillow to absorb the higher order frequencies and smoothen out the unwanted line induced harmonics. The line was tuned to around 80hz originally.

[ssSai]

Hello Ashok,

I already got an address (Thippasandra, Indranagar) where I can get MDF from "Nuwood". I yet have to visit it. Good to know as to how to make sure of its authenticity. I will check for the "MDF" stamped in blue.



Hello Ajju,

I wonder how Vivek got away with a coir stuffing. No one would have thought about the effect of its "weight" and also "weather". Its good that now, every one knows that "Coir" is a big NO-No as far as stuffing a sub up is concerned.

I HAVE A QUESTION ARISING AFTER READING THE POSTS.
??? WHAT WAS THE FUNGI DOING INSIDE THE SUBWOOOFER ???

MY ANSWER IS ---------------- LISTENING TO MUSIC. (Can anyone beat me in creativity??? )



Some people who have read this post already know about my sub configuration.

I am getting a "Adire Audio Shiva" 12" subwoofer driver.
The amplifier is posing some diffuculties. I wish I can get hold of a "AVA 250" dedicated subwoofer amplifier from "Adire Audio". But getting it all the way from the US is working out a bit tooooooo costly. The freight charges quoted was $172 (USD) to get it via air mail. Also you have the problem of customs.

Since this will be my first DIY project I want a "Sealed Enclosure". I have already been adviced to go for a "Ported" because I have approximately 4 cu.ft., but I am not confident about making one.





I will be keeping the subwoofer in its bare bone condition for some time because I plan to make a pair of full range speakers for my stereo setup. I will match all the three later with nice veeners maybe. I have already given thoughts about the "tinted glass". Its strange, but were you the one who told my dad to give me this advice??


Ajju, where did you get the JBLs from. I am yet undecided as to what drivers I will be using for my stereo setup.

[tcpip]

Dear Mister Navinbhai,

(See how intimidated I am by you now...)

Originally posted by navin
BTW why MDF. marine ply is just as good if not better. [/B]

In my limited experience, I seem to feel that MDF sounds deader than any ply. Secondly, you'll have to look closely to ensure that the chap is selling you good, real, marine ply. There is a lot of spurious and counterfeit ply going around. For instance, a good brand of ply in Western India is "Guna". There is a lot of counterfeit ply with the "Guna" label. Real "Guna ply" is easily one and a half times as heavy as a cheaper brand of commercial ply; I've used both (not for speakers, but for furniture. That's where I learned about counterfeit ply.) With MDF, I find it easier to just look at the sheet and know that it's real MDF, and the weight and sound tells me its quality.

I prefer to use "exterior grade" MDF rather than "interior grade", just because I presume that anything designed to lie exposed to water and sun will have better dimensional tolerance to weathering and temperature changes. Exterior grade 25mm MDF was about Rs.65/sft.

Third reason for me to use MDF is because I find it harder to find 25mm ply. MDF at 25mm (or even more) is easy to find. (I don't know why some of the others on this thread say MDF is hard to find... it's certainly easy to find even in New Bombay, let alone Bombay.)

However, the comparison between MDF and ply probably is merely academic, because both need to be deadened. I prefer to use tiles or bituminised felt or 12mm glass sheets stuck to the inner surface to "weigh it down" and deaden it. After such treatment, I suspect both ply and MDF will be equally good. And then I prefer to finish the outside using wood veneer, which adds another 4mm of ply to the walls, making it a composite effectively. And I prefer to stick the veneer using Araldite instead of the carpenter-standard Fevicol, because Araldite has a lot of "body". This makes the Araldite itself another layer, making the wall even more of a composite structure. With all this internal and external layering, I feel the difference between ply and MDF may become less relevant.

My two bits. What do you think?

regards,
Tarun

[navin]

Originally posted by tcpip
Dear Mister Navinbhai,

(See how intimidated I am by you now...)

In my limited experience, I seem to feel that MDF sounds deader than any ply. Secondly, you'll have to look closely to ensure that the chap is selling you good, real, marine ply. There is a lot of spurious and counterfeit ply going around. For instance, a good brand of ply in Western India is "Guna". There is a lot of counterfeit ply with the "Guna" label. Real "Guna ply" is easily one and a half times as heavy as a cheaper brand of commercial ply; I've used both (not for speakers, but for furniture. That's where I learned about counterfeit ply.) With MDF, I find it easier to just look at the sheet and know that it's real MDF, and the weight and sound tells me its quality.

I prefer to use "exterior grade" MDF rather than "interior grade", just because I presume that anything designed to lie exposed to water and sun will have better dimensional tolerance to weathering and temperature changes. Exterior grade 25mm MDF was about Rs.65/sft.

Third reason for me to use MDF is because I find it harder to find 25mm ply....However, the comparison between MDF and ply probably is merely academic, because both need to be deadened. I prefer to use tiles or bituminised felt or 12mm glass sheets stuck to the inner surface to "weigh it down" and deaden it. After such treatment, I suspect both ply and MDF will be equally good. And then I prefer to finish the outside using wood veneer, which adds another 4mm of ply to the walls, making it a composite effectively. And I prefer to stick the veneer using Araldite instead of the carpenter-standard Fevicol, because Araldite has a lot of "body". This makes the Araldite itself another layer, making the wall even more of a composite structure. With all this internal and external layering, I feel the difference between ply and MDF may become less relevant.

My two bits. What do you think?

regards,
Tarun

tarun, u have covered all the points....getting the good stuff requires knowledge of wood. the best guide is kg/sq. ft. the higher the better. araldite is much better than fevicol. it lasts forever. once you build a cabinet using araldite you wont be able to take it apart. besides araldite is water resistant to can handle hot humid climes of bombay a bit better.

here is my take....

I started out using 35mm MDF (rs. 80 / sq. ft) and found out hick wood stores too much energy.

so in my later cabiets I reduced the wood to 18mm and increased bracing so that all cabinet resonances were in the upper midbass freq. these freq were damped using dacron or fiberglass. dacron is easier to work with but more expensive.

my latest cabinet is in the works. i did post a few pics a few months ago. the cabinet is 48" x 10" x 16" (HWD).

the sides of the cabinet uses 3 layers of 3mm MDF (external grade) and 3 layers of 4mm marine ply. i braced the cabinet at 4", 5", 6", 7" and 8" intervals using 35mm external MDF. the front and back are 35mm MDF.

the six layers are bent (pre stressing the wood reduces flex).

then i applied a layer of fiberglass matting on the inside bonded with resin.

then i got som 1.5mm lead sheet from Pydhonie (near Crawford market). 3' x 8' of lead sheet weighs 40kgs and cost Rs 1836. should be enough to damp both cabinets and also leave some for the center channel and DVD player.

now i will apply the lead sheet with araldite to some of the walls.

I normally use 1.5 mm veneer but this time I am painting the cabinets black.

Now as far as intimidation is concerned you better stop calling me Bhai. You dont want the "real" Bhais to take umbrage to this. And the next time anyone calls me Mr. a Moderator will pay them a visit. to quote Jason L "There are 8 moderators. All over 7 feet tall. All over 17 stone. All trained athletes with bulging muscles and hair trigger reflexes. Each moderator is equipped with two low slung colt 45's, night vision glasses and armour piercing tracer shells."