[Folsom]

You're not like us Euro/US guy's; if you wanted to win a war with us the real secret is to just steal all our boots... we can't walk without shoes besides on grass and medium temperature sand.

Do you guys use metric or imperial?

[rajesh]

You're not like us Euro/US guy's; if you wanted to win a war with us the real secret is to just steal all our boots... we can't walk without shoes besides on grass and medium temperature sand.

Yes, I know. Wish my ancestors resisting colonisation knew this at that time.   

Do you guys use metric or imperial?

We use both interchangeably.

[rajesh]

I had bought the below foam sheet which has a density is 30 KG/M3 and he thickness is 18 mm. I found the performance to be quite impressive. 



Now for the rest of the pictures of the Subwoofer build:

The inner box



The Stainless Steel feet was procured from a forumer of the other forum who runs an metal fabricating company.





The original hole was not only too small to accommodate a bolt sufficiently thick to fix the feet but also was a through hole. Hence, they were modified to enable affixing them onto the outer panel of the subwoofer. The  holes were made bigger and also threaded to accommodate bolts of sufficient thickness.

Fixing of feet onto the outer panel.




Epoxy Resin glue was used to prevent loosening of bolt on constant vibration of the subwoofer[/U]


Outer panel with the feet fixed.



Processing the river sand involved the following:

Removal of dust and extremely fine clay particles was attempted by tossing the sand and blowing air through a fan like farmers winnowing the agricultural produce to separate out the chaff. Though dust was removed, this tedious process also resulted in loss of fine sand grains.
I figured that it is easier to wash the sand multiple times to get rid of the mud and clay.



Sanitising the sand to rid it of Fungal spores and Insect eggs was done by boiling the sand thoroughly after which, it was sun dried.







Sieving the sand was carried out to separate particles into fine, medium and coarse particles and pebbles.







Medium sand was used to fill the subwoofer. Some pics of subwoofer building.

Inner shell







Finished subwoofer

[rajesh]

The router bit used for chamfering the backside of the woofer hole.



Forgot to add the picture earlier.

As the build is progressing towards the finalisation, the work is getting more critical, delaying the progress. We have made the speaker grills with teakwood strips. Here are some build pics of the grills.













Affixing of a plywood piece at the bottom to handle the weight of sand and transferring it to the spikes



The (almost) finished speakers







We need to round off the edges of all the speakers which will be done in the circular saw. It has a special arrangement to do so while the subwoofer would be done with the router.

[gregfisk]

Fascinating pictures Rajesh! I'm embarrassed to admit my shop is pretty messy most of the time and sometimes I don't have much counter space to work with. I also don't always measure in the conventional way, at least after I get the first piece right.

These guys walk around and work in a disaster zone, barefoot no less and still come out with nice product in the end. Just goes to show there are many ways to get things done. What are your plans for the rest of the box finish wise? The teak is a nice touch.

Greg

[Folsom]

I get the impression you guys are skilled at doing a lot with not too much. I on the other hand am more like how I am with shoes, if I got all the tools to do the work I'm fine .

[rajesh]

@Greg,  thank you for the compliments. Though I wanted to go in for veneer, since I also wanted to round off the edges,  I've decided to go for PU coat over artificial teakwood finish albeit in a darker shade.

@Folsom, you are attributing nonexistent skills to me. All the carpentry skills are that of the two brothers,  especially Santhosh.

[rajesh]

@Danny, some folks on the other forum have commented that the grills are quite thick and deep and may have adverse effect on the sound quality. The speaker grills are 2 cms deep and that of the subwoofer is about 25mm.

Do you also feel so?

Opinions of other experts are also welcome.

[Folsom]

@Danny, some folks on the other forum have commented that the grills are quite thick and deep and may have adverse effect on the sound quality. The speaker grills are 2 cms deep and that of the subwoofer is about 25mm.

Do you also feel so?

Opinions of other experts are also welcome.

The sound waves are so much longer than 25mm on the subwoofer that I doubt a whale could hear the difference. But I'll await comments about the speaker grills from someone who knows better.

[G Georgopoulos]

@Danny, some folks on the other forum have commented that the grills are quite thick and deep and may have adverse effect on the sound quality. The speaker grills are 2 cms deep and that of the subwoofer is about 25mm.

Do you also feel so?

Opinions of other experts are also welcome.

grills when comes to bass don't matter,and very little to midrange and tweeter

that's my opinion,hope it helps.

[gregfisk]

@Danny, some folks on the other forum have commented that the grills are quite thick and deep and may have adverse effect on the sound quality. The speaker grills are 2 cms deep and that of the subwoofer is about 25mm.

Do you also feel so?

Opinions of other experts are also welcome.

I believe Danny will agree with this, the grills will effect the higher frequencies more than the lower but I know he doesn't like deep grills.

[Danny Richie]

The grill will not have any effect on the sub.

The fabric itself won't have much effect on the speakers either, but the frames will. Take a router and put a 1/2" radius on the inside edge of the frame so that the reflection will be that of a rounded corner instead of a square edge. That will help a lot.

And take it slow and easy knocking off that inside edge so that you don't break the frames. Just take a little off at a time.

[bdp24]

For anyone living in the U.S. using sand inside an enclosure, I found some great Silica ideal for that application. I found it at a building supply yard, in a 100 lb. bag for seven bucks and change. It's called Silver Sand by P.W. Gillibrand Co., of Simi Valley, California. It's intended purpose is for sand-blasting, and is available in various grades---just as with buckshot, the higher the grade number, the smaller the size of the sand grains. #10 is about the size of the sand commonly found (though a different color---about like MDF, with some black grains mixed in), and Gillibrand offers it also in 20, 30, 40, 50, 60, and higher grades. I looked at them all, and selected #60---anything smaller looked more like powder than sand. The sand is, unlike typical sand, non-organic (it's man-made, from Silica), so there is no need to wash it to prevent mold from growing inside your enclosure!

Great stuff, but it would cost more to ship it that it's worth, so those of you not in S. California might be better off looking for a local equivalent.

[lacro]

For anyone living in the U.S. using sand inside an enclosure, I found some great Silica ideal for that application. I found it at a building supply yard, in a 100 lb. bag for seven bucks and change. It's called Silver Sand by P.W. Gillibrand Co., of Simi Valley, California. It's intended purpose is for sand-blasting, and is available in various grades---just as with buckshot, the higher the grade number, the smaller the size of the sand grains. #10 is about the size of the sand commonly found (though a different color---about like MDF, with some black grains mixed in), and Gillibrand offers it also in 20, 30, 40, 50, 60, and higher grades. I looked at them all, and selected #60---anything smaller looked more like powder than sand. The sand is, unlike typical sand, non-organic (it's man-made, from Silica), so there is no need to wash it to prevent mold from growing inside your enclosure!

Great stuff, but it would cost more to ship it that it's worth, so those of you not in S. California might be better off looking for a local equivalent.

I use Black Beauty blast media.

Low Free Silica, Low Dusting & Chemically Inert
BLACK BEAUTY® blasting abrasives are a preferred alternative to silica sand. Silica sand can contain up to 99% free silica which has been found to cause silicosis, a sometimes fatal lung disease. BLACK BEAUTY® abrasives are low dusting, chemically inert, contain less than 0.1% free silica, and are not causally linked with any disease, including silicosis. See the CDC's Health Report.

http://www.blackbeautyabrasives.com/products/black-beauty-original-abrasives.php

[rajesh]

Thank you Folsom, G Georgopoulos & Gregfisk for chipping in with your comments. They sure were helpful.

Take a router and put a 1/2" radius on the inside edge of the frame so that the reflection will be that of a rounded corner instead of a square edge. That will help a lot.

That's a great input Danny. I'll implement it right away. 

@Bdp24 & Lacro, great info that.  Having procured the sand already, I may not go in search of those but it might be useful for those who are yet to commence their builds.

[bdp24]

I use Black Beauty blast media.

Low Free Silica, Low Dusting & Chemically Inert
BLACK BEAUTY® blasting abrasives are a preferred alternative to silica sand. Silica sand can contain up to 99% free silica which has been found to cause silicosis, a sometimes fatal lung disease. BLACK BEAUTY® abrasives are low dusting, chemically inert, contain less than 0.1% free silica, and are not causally linked with any disease, including silicosis. See the CDC's Health Report.

http://www.blackbeautyabrasives.com/products/black-beauty-original-abrasives.php



Excellent! There's a Black Beauty retailer only four miles from me, so I'm gonna check it out.

[rajesh]

Take a router and put a 1/2" radius on the in Inside edge of the frame so that the reflection will be that of a rounded corner instead of a square edge. That will help a lot.

The speakers have finally reached home on Saturday evening but the dyeing and finishing work is held up as there was bereavement in the family so I'm at my wife's place 1000 miles away attending a funeral and the related rituals.

Before taking delivery of the  speakers, I've got shaved off the depth of the frames by 5mm. Now they all are 20 mm deep (except that of subwoofer which is 30 mm) Will that improve things? From the specs of the driver, the Xmax of the driver is only 3.6 mm. So if I further reduce it to say 10 to 15 mm (anything in between,  will it improve further?

Another thing is about rounding off the inner edge. I want tk be sure that it is the top inner  edge, ( The one that is away from the driver and not the one that is resting on the baffle.)

Sorry for so many questions. 

[Danny Richie]

Before taking delivery of the  speakers, I've got shaved off the depth of the frames by 5mm. Now they all are 20 mm deep (except that of subwoofer which is 30 mm) Will that improve things? From the specs of the driver, the Xmax of the driver is only 3.6 mm. So if I further reduce it to say 10 to 15 mm (anything in between,  will it improve further?

Your frame depth is fine.

Another thing is about rounding off the inner edge. I want tk be sure that it is the top inner  edge, ( The one that is away from the driver and not the one that is resting on the baffle.)

Yes, the front facing or forward facing inside edge. Not what touches the surface of the baffle.

[rajesh]

Thank you for the advice Danny. I'll implement it straight after I get back.