Hello friends,
A while ago I bought an immaculate pair of JBL 2213H for a very fair price. I have always heard that these woofers produce a very clean and deep bass in large enclosures. So I decided to build a pair of speaker out of them. I got a pair of Morel TSCM 634 midrange drivers and a pair of Aurum Cantus G1 Ribbon Tweeters from Parts-Express. After two weeks of measuring and building xo, I managed to get a very flat and surprisingly fantastic sound from them. The only issue is that the woofers still play bass frequencies of 100-50Hz a little too loud for my taste. The test cabinet I have put them in right now were built for a DIY JBL L100T (ten years ago or so). I guess they are like 60L or maybe a little bit larger.
According to WinISD a volume of about 100L with a long port of 26" (length) and 4" (diameter) should make them sound right. So I have decided to use PVC swage pipes and use 90-degree bends to make the port fit. Please see the drawings attached.
Any input about what I am going to do is greatly appreciated. Do my calculations make sense? Is the port OK? How about, if the vertical end of the port goes even higher than the woofer? Should I be worried about any kind of distortion or resonance from such a port?
Please see the attached pics.
Thanks.
A while ago I bought an immaculate pair of JBL 2213H for a very fair price. I have always heard that these woofers produce a very clean and deep bass in large enclosures. So I decided to build a pair of speaker out of them. I got a pair of Morel TSCM 634 midrange drivers and a pair of Aurum Cantus G1 Ribbon Tweeters from Parts-Express. After two weeks of measuring and building xo, I managed to get a very flat and surprisingly fantastic sound from them. The only issue is that the woofers still play bass frequencies of 100-50Hz a little too loud for my taste. The test cabinet I have put them in right now were built for a DIY JBL L100T (ten years ago or so). I guess they are like 60L or maybe a little bit larger.
According to WinISD a volume of about 100L with a long port of 26" (length) and 4" (diameter) should make them sound right. So I have decided to use PVC swage pipes and use 90-degree bends to make the port fit. Please see the drawings attached.
Any input about what I am going to do is greatly appreciated. Do my calculations make sense? Is the port OK? How about, if the vertical end of the port goes even higher than the woofer? Should I be worried about any kind of distortion or resonance from such a port?
Please see the attached pics.
Thanks.
Attachments
Troels has used bent ports like that a few times (example), so it certainly should work in principle.
The bend plus the port exiting the box on the rear will both help filter out any extraneous midrange that might otherwise get into the port from having it up near the backside of the driver IMO.
I guess it wouldn't hurt to place a brace across the box just below the main driver so that the port can be secured to it - just in case the port tube itself vibrated.
Edit - tidied up the link.
The bend plus the port exiting the box on the rear will both help filter out any extraneous midrange that might otherwise get into the port from having it up near the backside of the driver IMO.
I guess it wouldn't hurt to place a brace across the box just below the main driver so that the port can be secured to it - just in case the port tube itself vibrated.
Edit - tidied up the link.