Peerless Subwoofer

[Gijo George]

I had bought the 12 Peerless driver and 150W plate amp as part of the group buy organized by George and T Antony last year. Been putting away the build for a while now but decided its now or never.

The enclosure plans were provided by Antony here http://www.hifivision.com/diy/22681-diy-sub-using-peerless-driver-available-locally-2.html.

A few queries before I start off.
1. TJ's plan doesn't have braces. But I intend to provide two square braces in 3/4" mdf 16.5" x 16.5" with a 32cms dia cut out at the center. (Same dia as the cut out in the front outer baffle.) The braces would be placed parallel in equal distance between the front and back panel. The depth of the enclosure would be increased by 1" to make up the loss in internal volume. Would this work fine?

2. The above braces which I plan to place at about 6" & 12" from the driver, won't allow for the port to be placed on the front (the port's 12" long) Can I place the port on the rear panel such that the the inside end falls anywhere within the 32cms dia of the brace?


So heres the cut list I've prepared. Material planned MDF

1. Front & Back (Outer) 18 x 18 = 2
2. Front & Back (Inner) 16.5 x 16.5 = 2
3. Braces 16.5 x 16.5 = 2
4. Sides 16.5 x 19 = 2
5. Top and Bottom 18" x 19" = 2

Would really appreciate any inputs on the above.
Thanks

 

[t.antony]

I had bought the 12 Peerless driver and 150W plate amp as part of the group buy organized by George and T Antony last year. Been putting away the build for a while now but decided its now or never.

The enclosure plans were provided by Antony here http://www.hifivision.com/diy/22681-diy-sub-using-peerless-driver-available-locally-2.html.

A few queries before I start off.
1. TJ's plan doesn't have braces. But I intend to provide two square braces in 3/4" mdf 16.5" x 16.5" with a 32cms dia cut out at the center. (Same dia as the cut out in the front outer baffle.) The braces would be placed parallel in equal distance between the front and back panel. The depth of the enclosure would be increased by 1" to make up the loss in internal volume. Would this work fine?

2. The above braces which I plan to place at about 6" & 12" from the driver, won't allow for the port to be placed on the front (the port's 12" long) Can I place the port on the rear panel such that the the inside end falls anywhere within the 32cms dia of the brace?


So heres the cut list I've prepared. Material planned MDF

1. Front & Back (Outer) 18 x 18 = 2
2. Front & Back (Inner) 16.5 x 16.5 = 2
3. Braces 16.5 x 16.5 = 2
4. Sides 16.5 x 19 = 2
5. Top and Bottom 18" x 19" = 2

Would really appreciate any inputs on the above.
Thanks

I have not found bracing as effective as lining the entire inner side with bitumen sheets or fiber glass.

Braces would be fine If you are planning for a sealed box, but for the ported enclosure I would not recommend braces as they will contribute to turbulence inside the enclosure. This turbulence can interfere with the back wave and could change the output from the port.

- You can have up to 6mm of bitumen lining with the original dimensions in my thread, which would be more than adequate to deaden the enclosure.
- Also it's important that both ends of the port are flared.

 

[GeorgeO]

I think for this size there is no need to brace.

 

[Gijo George]

Hi TJ/HFV's
I've tried in around 4 shops right now but could not find a pipe of 90mm dia for the port. Its either 3" (78mm) or 4" (+100mm). Given the existing enclosure dimensions can we substitute with the 3" or 4" pipe in same (12") or different lengths for the port?
Thanks
Gijo

 

[sbg]

Gijo,
You should have checked the inner diameter of the 4" pipe.
in the normal construction industry paralance they refer 3.5"(inner diameter ) as an 4" dia pipe.

Also do consider to to get a bit longer than 12 inch if you plan to make a flare at either of the ends.You may have to consider the radius of the flare at one or both the ends as 12 inches and the other radius will be the extra length you would need.

port-flares

 

[t.antony]

Hi TJ/HFV's
I've tried in around 4 shops right now but could not find a pipe of 90mm dia for the port. Its either 3" (78mm) or 4" (+100mm). Given the existing enclosure dimensions can we substitute with the 3" or 4" pipe in same (12") or different lengths for the port?
Thanks
Gijo

This design is optimized for 3.5 inches dia port. Smaller diameter is not recommended as it could lead to chuffing at higher SPLs.

Larger dia pipes would require longer port length and you might have to use a bent to accommodate it within the enclosure.