[JoeFish]

Hey all. I'm building the Adire 85L vented design for the Shiva III using their reference design. This is my first vented sub, and my first home theater sub.

When I calculated the actual interior volume of the box in Adire's plans, it was about 89.5l, so that's the value I'm using for my box. My box is about 89l inside, taking into account all of the bracing and whatnot.

I've got a couple of questions:

Would it be beneficial to use some kind of damping material on the walls of the box?

What would I use, jute or something similar?

Would this change the tuning of the box?

Any other suggestions before I button it up?

Thanks!

-Joe

[Dave Poehlman]

I've heard of people putting modelling clay or dynamat on the interior of their enclosures. This is strictly to deaden the box and provided a large amount isn't used, it shouldn't affect the overall box tuning. However, if you've built a solid, well braced enclosure, I think clay or dynamat is a little extreme IMO.

Also, if you haven't considered it: HERE is an article from a car audio website that says even ported enclosures will benefit from stuffing with polyester fiberfill.

[JoeFish]

I'm aware that stuffing the box will make it appear larger, but if the alignment of the vented box is designed for 89l, won't stuffing it ruin the alignment?

I had contacted Adire about this and they said...let me find the email...I had asked them if it was OK to build the box a bit smaller and stuff it. They responded:

Quote:

We geneally recommend no more then 50% fill (8 oz per
cubic foot) for vented enclousres. In this case, it is possible to subtract 5-10 percent of the volume. However, in most of the time, I wouldn't recommend using fill to fudge volumes. I would use the damping to fine tune
the overall performance characteristics.

-Joe

[Chris Tsutsui]

Yeah, I'd go to walmart and pick up 5lbs of polyester fiberfill for about $5-6. Fill the box lightly and keep the stuffing away from the driver or ports. I've heard of cases where stuffing was melted onto the driver. If you fill the ports with polyfil they won't perform the same, and it may just shoot fil out onto the floor.

I just tried out this new stuff called polyester clusters. It seems to work just as well as polyfil except it's easier to work with.

When i put fill in a box, it seems to basically tighten up the bass a bit, and slightly reduce boom. I wouldn't coat the sides of the box with anything like dynamat as that most likely won't help.

If you run the sims with box's 5-10 percent larger or smaller you'll see that it really won't make that much difference so don't sweat the small stuff and enjoy your sub. I lined my walls and added a little stuffing but it was more because I could then I needed to if you know what I mean.

[Dave Poehlman]

Quote:

but if the alignment of the vented box is designed for 89l, won't stuffing it ruin the alignment?

I think I see what you're getting at.. you're asking if you stuff the box and make it act as say a 100l box, has the overall alignment changed? That's a good question... and I'm not sure I can answer that. Perhaps someone else here can. I don't think it does, because you're still dealing with the same amount of air in the box (save for the small amount displaced by the stuffing). The air is just working more efficiently by dissipating its heat better.

I can tell you that each and every driver's T/S parameters are different out of the factory. So, no 2 Shivas are exactly alike. Therefore, one Shiva might work marginally better in an 85l box than another based on minute differences in their construction.

Like Andrew said, don't sweat the small stuff... you'll go insane.

[JoeFish]

Quote:

Like Andrew said, don't sweat the small stuff... you'll go insane.

Ha! Too late

Seriously, I'm going to Nike and just build it. Adire recommends about 1/2lb per cu ft. 89l is a little over 3cu ft, so I'll cram 2 lbs of stuffing in there.

Thanks for the advice,

-Joe

[JoeFish]

Hello everyone! I wanted to thank you again for your suggestions, and post some pictures so you could see my progress.

The sub is now in my living room, performing like a champ. On movies like the Two Towers, the bass is immense, especially the flapping dragon wings. On music, the bass is tight and clean, and not overpowering. I'm happy with it, to say the least.

Click here to see the build process.

-Joe

[Dave Poehlman]

It looks great, Joe! Looks like a monster!

Quote:

On movies like the Two Towers, the bass is immense, especially the flapping dragon wings.

I know what you mean, I just watched the same scene with my sealed Shiva last night! I can just imagine the extension on a ported enclosure...

What are you going to finish it with? Or are you going to be a member of the "naked enclosure club"?

[JoeFish]

I'll be naked for a little while I plan on veneering it and putting a chessboard top on it to use as a coffee table.

We'll see how soon that gets done

-joe

[JoeFish]

A couple of new pictures posted...

My coffee table sub

[Frank Carter]

I'll be naked for a little while

I hope that's a typo Joe .