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Old 15th June 2009, 16:52   #46
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Originally Posted by shreyasma View Post
Shall I accompany you to the carpenter? May get some more ideas looking at them work. Helps a lot for my DIYs
If you are free this Saturday, you can join me. I will be going at around 11:00 am. Sounds good?
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Old 16th June 2009, 07:26   #47
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If you are free this Saturday, you can join me. I will be going at around 11:00 am. Sounds good?
Yea! I am free anyways. Will call you on Sat morning.
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Old 20th June 2009, 12:17   #48
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Congrats dude.
The Amp rack looks really lovely.
Cheers!
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Old 21st June 2009, 02:29   #49
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Originally Posted by hydrashok View Post
IMHO,taking a second (then third and then fourth) look at the way your existing ICE is set up is actually the best and the most intelligent way of improving your overall install without spending a lot of money on changing equipment.

Those comps are excellent and installed well, they can kick the backsides of many comps that cost a lot more. I've been guilty of judging them negatively in sub-par installs, before I heard them properly installed and tuned in iPlay's setup. You have the added advantage of a great headunit.
Thanks @hydrashok for the appreciation. I really appreciate you taking time and analyzing the setup. IMHO, if anyone loves natural expression of sound, it is hard to beat Polk Momo MMC 6500. They rock. And when paired with an amp like RF and HU like Eclipse, they are pure Nirvana stuff.

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Originally Posted by hydrashok View Post
I noticed that your sub-box looks like it is a ready-made one (going by the logo). If it is not within the recommended specs, you can perhaps consider changing it. If it is a ready-made one, it might have straight walls on all sides (can't make out from the photo if the rear is sloped). Having a sloping wall on at least one side will reduce standing wave issues.
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Originally Posted by DerAlte View Post
The way the sub box shows in the pics (4th pic in first post, 6th and 7th pics in third post) where it is lying on its back, looks like the rear wall is sloped.
The Sub box is from BassFx and is a ready-made one. It was 1.25 cubic feet and fell under recommended volume of 0.85 cubic feet to 1.25 cubic feet. But I wanted tighter bass and so have reduced the volume of the box to 0.85 cubic feet by putting inside wood blocks. I calculated the volume of the wood blocks and have put approximately 0.4 cubic feet of wood blocks.

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Originally Posted by hydrashok View Post
From what I've read, one way of checking for standing waves with the current box would be to open a door while music is playing. If the sub suddenly sounds louder/boomier, then you might benefit (a bit) from a box that eliminates standing waves. Now this would be an incremental change, more that a huge difference, but if you are looking at extracting the maximum from the current equipment, this might be one thing you can consider doing.
My long ordeal with my car's ICE-dscn5642.jpg

I took this picture today while I had opened up the Sub for inverting it so that the Punch logo appears straight. The box has it's back side slanted and thankfully I have put wood blocks only on three sides and not the slanted one. I will still check for the presence of Standing waves tomorrow and take a call if it needs any further tuning. Thanks for sharing.

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Originally Posted by abhinav.gupta88 View Post
Congrats dude.
The Amp rack looks really lovely.
Cheers!
Thanks Abhinav.
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Old 21st June 2009, 11:55   #50
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Originally Posted by shreyasma View Post
It can be considered inside. I need these for fibreglassing the mount for my 5.25 polks. Also need a set of 6.5" and 12" rings.

Shall I accompany you to the carpenter? May get some more ideas looking at them work. Helps a lot for my DIYs

you need 6 inch rings not 6.5 inch !!

the sub box looks like a plywood box , see carefully !! get mdf box man !!

Last edited by chiragh_bir : 21st June 2009 at 11:56.
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Old 21st June 2009, 12:02   #51
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Originally Posted by chiragh_bir View Post
the sub box looks like a plywood box , see carefully !! get mdf box man !!
The Sub box is MDF and BassFx make quite decent boxes. They are made in Goa and distributed. The plywood sheets that you see are blocks that I have put inside to reduce the volume. You may have been thinking something else while replying to this post.
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Old 21st June 2009, 12:43   #52
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i was not thinking anything, just saw pics and replied !!

Plywood in MDF box to reduce volume is something i can't digest... throw some light gurus !!

Secondly if Bass FX makes good boxes why couldn't they deliver a box for your taste?

Last edited by chiragh_bir : 21st June 2009 at 12:52.
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Old 21st June 2009, 12:54   #53
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Originally Posted by chiragh_bir View Post

Plywood in MDF box to reduce volume ...
... throw some light gurus !!
That's exactly why I have put up that picture. If people have suggestions, feedback, they can share it. I love that box for it's build quality and don't want to change it. It was my idea of reducing volume and it has been working well for last 12 months. And from what I understand, it doesn't matter if it's plywood inside. But if something is wrong or putting MDF blocks instead of plywood will help, I would like to know that. Is damping required?

One more question I have is this: the current volume of the box, 0.85 cubic feet, doesn't take into account the driver's volume. Should I subtract driver's volume while calculating the volume of the box?

Last edited by akbaree : 21st June 2009 at 12:58.
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Old 21st June 2009, 12:59   #54
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The total volume of the box ( according to the dimensions and thickness of the MDF board used) will include the Displacement offered by the sub.

For eg.
If according to the dimensions and thickness, the volume is 1 ft^3 and the displacement of sub approx 0.1ft^3, then the effective box volume would be 0.9ft^3
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Old 21st June 2009, 13:02   #55
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plywood is not made for audio setups man ...

better get a sealed 1.5 cu box , damping is not necessary but you can add polyfill or non expesive damping !!
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Old 21st June 2009, 13:28   #56
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Add polyfill or go for the recommended specs.
If you like the current one.
Make a new one with MDF completely at once and not by adding plywood inside.
This is because even though you have added some plywood sheets inside, there is some room / gap left on the sides which does account for added space
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Old 21st June 2009, 16:15   #57
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Guys, I was with Akbaree whole day yesterday for something that will be revealed later.

The box is very nicely built. Even though he has nailed in the plywood pieces to the inner walls its absolutely fine. Atleast not with the kind of music he listens to. It will just be extra money for a new box.

OT: @Chiragh, Yes I got 6". Typed 6.5 by mistake.
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Old 21st June 2009, 16:45   #58
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Quote:
Originally Posted by chiragh_bir View Post
plywood is not made for audio setups man ...

better get a sealed 1.5 cu box , damping is not necessary but you can add polyfill or non expesive damping !!
I think you are wrong here...in this case the plywood is just reinforcing the wall of the box nothing wrong in it but it will be better.

And I think 1.5 cuft for a 12 inch sub would be a little big and the sub would sound boomy.
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Old 21st June 2009, 19:10   #59
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Plywood or any other wood is just fine for reducing volume. For that matter any inflexible solid is, for example bricks (standard Indian brick is 0.07 cft, so 3 bricks will reduce 0.21 cft). The material should be stayed properly so that it doesn't shift around and possibly damage the sub.

Polyfill (or glass wool) has very little volume by itself, and actually has the reverse effect. It acts like an acoustic resistance behind the cone (and breaks up rear waves) - thereby making a small box appear larger to the sub cone, i.e. making it appear as if there is a much larger air mass.

Last edited by DerAlte : 21st June 2009 at 19:11.
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Old 21st June 2009, 23:50   #60
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Thanks everyone for your suggestions.

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Originally Posted by abhinav.gupta88 View Post
... even though you have added some plywood sheets inside, there is some room / gap left on the sides which does account for added space
In a sealed box only thing matters is the volume. The open corners would make no difference.

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Originally Posted by shreyasma View Post
The box is very nicely built. Even though he has nailed in the plywood pieces to the inner walls its absolutely fine. Atleast not with the kind of music he listens to. It will just be extra money for a new box.
When we meet next, let's try playing some of the music from your collection. That may give additional clues if the sub setup needs any further tuning.

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Originally Posted by DerAlte View Post
Polyfill (or glass wool) has very little volume by itself, and actually has the reverse effect. It acts like an acoustic resistance behind the cone (and breaks up rear waves) - thereby making a small box appear larger to the sub cone, i.e. making it appear as if there is a much larger air mass.
Sounds interesting. It may not be correct but I feel that's the reason why mufflers of those lound exhaust setups are filled with glass wool till the brim.

I still have two questions...
  1. I don't know if filling some glass wool is a good option as damping? If not, should I consider any other damping material?
  2. While calculating the volume of the box, what are the parameters I should consider. Abhinav pointed out driver displacement. But the driver itself takes up so much volume. Is that to be discounted for as well?
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