Could someone help me convert metric port length? The plans call for a length of 100mm and inside diameter of 40mm. Trouble is, I can only buy PVC pipe in standard inch sizes. So 40mm = 1.5748 inches. Is it close enough if I buy 1.5"? How would I adjust for that difference?
Or, if you've not already cut holes for the round ports before securing the pipe- or haven't actually glued the boxes together- you could fabricate a square or retangular port of equivalent CSA ( which might even permit a simple slot) from wood.
(CSA of 40mm diameter circle should be around 1260mm^2)
I hardly ever do conventional round ports anymore
(CSA of 40mm diameter circle should be around 1260mm^2)
I hardly ever do conventional round ports anymore
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Is it close enough if I buy 1.5"? How would I adjust for that difference?
Yes that will work by shortening the pipe down from 100mm to 3.5-3.625" long, in order to keep the box tuning the same. May not be super critical, depending on what the driver is. What are you building?
jeff
Yes that will work by shortening the pipe down from 100mm to 3.5-3.625" long, in order to keep the box tuning the same. May not be super critical, depending on what the driver is. What are you building?
jeff
Satellite speakers for a 2.1 system using Fostek FF85WK's in their recommended ported box (from the data sheet). The Lance design looks superior but these are for computer use with very limited desk space.
Excellent choice for a driver, although that box tuning looks totally wrong to me. 92Hz looks way too high for a 3L (~3.58 - driver & port tube) box. 80Hz would be much better, but a 1.5" dia. port won't fit in the box, so you'll have to go down to 1.25" dia. port x 4.0" long.
Hopefully someone will confirm my calc's regarding this enclosure.
https://www.madisoundspeakerstore.com/approx-3-fullrange/fostex-ff85wk-3-full-range/
jeff
Hopefully someone will confirm my calc's regarding this enclosure.
https://www.madisoundspeakerstore.com/approx-3-fullrange/fostex-ff85wk-3-full-range/
jeff
Hi mattmcl,
Here's another compact design for the FF85WK:
http://p10hifi.net/FAL/downloads/uFonkenWK-1v0-plan-130312.pdf
IIRC Dave (P10) has other slightly large box designs too.
Here's another compact design for the FF85WK:
http://p10hifi.net/FAL/downloads/uFonkenWK-1v0-plan-130312.pdf
IIRC Dave (P10) has other slightly large box designs too.
I'm surprised Fostex recommends that enclosure though.
Don't be surprised, sadly there are other examples. The microFonken is an excellent design, well worth the extra effort compared to a simple box.
jeff
The microFonken design Jeff mentions is an example of narrow slot porting that works quite well, and for which it's very easy to adjust.
Not all of Fostex's "recommended" enclosures deliver optimal performance for their drivers, and I suspect this is one. The 85WK is not a woofer, but when XO's in the circa 100Hz range to a sub, can do very well in a desk-top application
Not all of Fostex's "recommended" enclosures deliver optimal performance for their drivers, and I suspect this is one. The 85WK is not a woofer, but when XO's in the circa 100Hz range to a sub, can do very well in a desk-top application
The microFonken design Jeff mentions is an example of narrow slot porting that works quite well, and for which it's very easy to adjust.
Not all of Fostex's "recommended" enclosures deliver optimal performance for their drivers, and I suspect this is one. The 85WK is not a woofer, but when XO's in the circa 100Hz range to a sub, can do very well in a desk-top application
Well that's good news. I was expecting to have to cross at 150. The sub I'm using is a ported 8" which is very good at that range. Thanks.
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