3-way design...
Due to construction constraints, a typical 'box' enclosure for the mid out of ply doesn't seem possible in the design I'm working on. However I can make this configuration work if I use a 6" pvc tube between the baffle and rear panels.
This chamber would need to be ported. Is there any down side or considerations when doing this?
thanks
Due to construction constraints, a typical 'box' enclosure for the mid out of ply doesn't seem possible in the design I'm working on. However I can make this configuration work if I use a 6" pvc tube between the baffle and rear panels.
This chamber would need to be ported. Is there any down side or considerations when doing this?
thanks
With glass wool stuffing there is no peak.
6" PVC works well with midranges up to 5". 6" midrange need 8" PVC.
Thanks for the replies.
Ok, not having seen this done before I have more noob questions...
So can I ignore the fact this is a cylindrical tube and just treat it like a small box enclosure (approx. 5L), 25mm round port? at the rear with glass stuffing in the tube and stuffing in the port to 'tune' it by ear, is that the idea?
Ok, not having seen this done before I have more noob questions...
So can I ignore the fact this is a cylindrical tube and just treat it like a small box enclosure (approx. 5L), 25mm round port? at the rear with glass stuffing in the tube and stuffing in the port to 'tune' it by ear, is that the idea?
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-do NOT do that. (..it kills low-level detail, though that is driver dependent)
Instead stuff the entire volume with plastic drinking straws - making the cross-section "honeycomb-ish".
(obviously keep a separate volume for your port if you plan on using a bass reflex.. BUT preferably use a passive radiator and avoid that.)
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Yes, that's exactly the same as I want. So totally open at the rear baffle?
I really want to use the Dayton PS95-8 3 1/2" for a mid, but as I understand it it's suited for a vented enclosure. I could see how it could work in a very lossy aperiodic?
ScottG said:
You're suggesting I fit the port at the rear and fill the rest of the tube with straws but not in the port, correct?
I'm not understanding how I could use a PR here TBH.
cheers
Thanks for the replies.
Ok, not having seen this done before I have more noob questions...
So can I ignore the fact this is a cylindrical tube and just treat it like a small box enclosure (approx. 5L), 25mm round port? at the rear with glass stuffing in the tube and stuffing in the port to 'tune' it by ear, is that the idea?
The KEF concerto used a sealed cardboard tube for the mid-range with about three inches of foam just at the rear. Why do you want to use a port and tune it?
Porting is a means of tuning and extending the low frequency output, which is not what you want to do when using it as a midrange driver
It depends You can use an open baffle if you can keep them a sufficient distance from the front wall, usually a minimum of three feet, the crossover frequency isn't too low, and the baffle isn't too small. You could use an open backed tube but again it could restrict how close you could put it to the front wall depending on how much the back wave is damped
You can use an open baffle if you can keep them a sufficient distance from the front wall, usually a minimum of three feet, the crossover frequency isn't too low, and the baffle isn't too small. You could use an open backed tube but again it could restrict how close you could put it to the front wall depending on how much the back wave is dampedSpeaker I believe to be very neutral in the midrange, the JBL LSR32 studio monitors have a sealed thin walled metal tube, or effectively a flat bottomed can, for the midrange enclosure. A fiberglass batt is rolled up and fills the entire volume. Cylinder walls are very stiff, dense fiberglass absorbs well. Above a few hundred Hz, a sound wave traveling back and forth through 8" of packed fiberglass batting is reduced by some 40 dB, so having a back wall or not will have very little effect on the response. Use one of those 6" plumbing end caps and you can measure the response with it on or off. Good fun.
Nonsense.-do NOT do that. (..it kills low-level detail, though that is driver dependent)
Instead stuff the entire volume with plastic drinking straws - making the cross-section "honeycomb-ish".
If you are doing it "open-baffle" like that then don't worry about a bass reflex design (either vent or passive radiator). (..again, using it as a mid.)
Make sure however that the diameter of the pipe is considerably larger than the driver's diameter.
Instead of PVC consider a variation of sonotube (..say 10" tube for a 6" driver). Search for cement forming tubes for more information.
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