Stuffing and Port Length- Fostex 167

Pathmark · 13th July 2007, 10:22 PM

I recently purchased some very nice cabinets sized for Fostex167 drivers. Unfortunately that is all the details provided. Can anyone help with suggestions for damping material and quanity and port length.

The cabinet dimensions are as follows: 8.5" x 10.75" x 16.25" (wxdxh).

The cabinet material is 3/4" mdf all around. Port opening is 2" diameter.

Thanks in advance for your help.
Pathmark

vinylkid58 · 14th July 2007, 12:38 AM

Based on the given outside cabinet dimensions, you have a volume of approx. 15.66 Liters. Subtract ~.5L for port volume & driver we get 15.16L.
A 2" dia. vent 2.26" long would give you a tuning freq. of 65Hz in a 15.16L vented box.
I used WinISD to generate these numbers. Hope this helps.

Jeff

Pathmark · 15th July 2007, 12:34 PM

Sounds like a start for me, thank you for your help.

Pathmark

vinylkid58 · 15th July 2007, 05:24 PM

I forgot to ask if the boxes are sealed, or if they have a removable rear baffle for ease of adding some damping material to the inside surfaces.

Jeff

Pathmark · 15th July 2007, 10:05 PM

They are sealed but I can add damping material through the speaker hole. I have some of th polyester fill, just not sure how much to use.

pathmark

vinylkid58 · 15th July 2007, 10:45 PM

Quote:

Originally posted by Pathmark
They are sealed but I can add damping material through the speaker hole. I have some of th polyester fill, just not sure how much to use.

Lightly stuffed should work fine, you want just enough to stop cab. reflections. Do your cabs. have threaded inserts for the machine screws or do they just have wood screws for mounting the drivers? Using machine screws allows you to remove the driver as much as you want to play with damping/stuffing.

Jeff

Pathmark · 16th July 2007, 02:58 AM

Just standard wood screws, so I guess I should avoid removing too many times. Do have any thoughts on using polyfil or something like acoustic foam (sonic barrier-parts express)?

vinylkid58 · 16th July 2007, 05:05 AM

1/2" Sonic Barrier w/PSA might be the way to go for ease of installation, with the only access thru the driver hole. It would surly equal cotton felt (bump) and standard open cell foam acoustically, and is fairly inexpensive. Felt maybe a bit cheaper but it's going to be a real pain to install, not worth the extra frustration IMHO.

Jeff

13th July 2007, 10:22 PM	#1
Pathmark diyAudio Member Join Date: Jan 2007	Stuffing and Port Length- Fostex 167 I recently purchased some very nice cabinets sized for Fostex167 drivers. Unfortunately that is all the details provided. Can anyone help with suggestions for damping material and quanity and port length. The cabinet dimensions are as follows: 8.5" x 10.75" x 16.25" (wxdxh). The cabinet material is 3/4" mdf all around. Port opening is 2" diameter. Thanks in advance for your help. Pathmark

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14th July 2007, 12:38 AM	#2
vinylkid58 diyAudio Member Join Date: May 2005 Location: Victoria, B.C.	Based on the given outside cabinet dimensions, you have a volume of approx. 15.66 Liters. Subtract ~.5L for port volume & driver we get 15.16L. A 2" dia. vent 2.26" long would give you a tuning freq. of 65Hz in a 15.16L vented box. I used WinISD to generate these numbers. Hope this helps. Jeff

15th July 2007, 12:34 PM	#3
Pathmark diyAudio Member Join Date: Jan 2007	Sounds like a start for me, thank you for your help. Pathmark

15th July 2007, 05:24 PM	#4
vinylkid58 diyAudio Member Join Date: May 2005 Location: Victoria, B.C.	I forgot to ask if the boxes are sealed, or if they have a removable rear baffle for ease of adding some damping material to the inside surfaces. Jeff

15th July 2007, 10:05 PM	#5
Pathmark diyAudio Member Join Date: Jan 2007	They are sealed but I can add damping material through the speaker hole. I have some of th polyester fill, just not sure how much to use. pathmark

16th July 2007, 02:58 AM	#7
Pathmark diyAudio Member Join Date: Jan 2007	Just standard wood screws, so I guess I should avoid removing too many times. Do have any thoughts on using polyfil or something like acoustic foam (sonic barrier-parts express)?

16th July 2007, 05:05 AM	#8
vinylkid58 diyAudio Member Join Date: May 2005 Location: Victoria, B.C.	1/2" Sonic Barrier w/PSA might be the way to go for ease of installation, with the only access thru the driver hole. It would surly equal cotton felt (bump) and standard open cell foam acoustically, and is fairly inexpensive. Felt maybe a bit cheaper but it's going to be a real pain to install, not worth the extra frustration IMHO. Jeff

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