Hi all, just wondering if anyone has any experience in using elbow joints on bass relfex vents and any potential issues / pitfalls I should be aware of?
I'm currently building a fairly small bass reflex enclosure, which will require a 90 degree elbow in the vent to fit the required length. I'm planning to seal up the elbow section with a load of glue and sealant to make sure it is airtight and keep the correct clearance to the inner walls.
Has anyone had any issues with a method such as this rather than a single section of bent duct?
Thanks in advance,
Andy 🙂
I'm currently building a fairly small bass reflex enclosure, which will require a 90 degree elbow in the vent to fit the required length. I'm planning to seal up the elbow section with a load of glue and sealant to make sure it is airtight and keep the correct clearance to the inner walls.
Has anyone had any issues with a method such as this rather than a single section of bent duct?
Thanks in advance,
Andy 🙂
I've done this several times. No issues really but you may experience slightly lower tuning frequency than expected due to the increased airflow resistance.
No need for additional sealant, just use plenty of glue. I usually use epoxy for this.
No need for additional sealant, just use plenty of glue. I usually use epoxy for this.
I use PVC pipe from diy shops for my ports, 90 degree bends are just the ones you buy to go with the pipe. They are more curved than mitre cutting tube.
If you use a slotted port (which might be the case if external physical size should be small) made with mdf/plywood sheet, the 90 degree angle can push your tunning much lower.
I have used 90 degree 3" PVC (unreasonably heavy, very non-resonant) and 3" shop vacuum hose elbows for years. These have a gentle bend. Works well for me. I find that the joint on the inside where the tube inserts into the elbow leaves only a small crack, which one could fill with caulk after gluing if desired.
I also buy a flared port kit for the flared ends and any needed straight tubing. Since a 3" elbow tends to be heavy, I add a brace.
I don't recommend using an elbow that is just two straights joined together. There is a well known supplier of DIY gear who sells a port elbow that is basically this! There will be a large resistance to air flow due to the air having to make a drastic 90 degree turn, rather than a gradual bend. This loss in not present in a straight port.
I also buy a flared port kit for the flared ends and any needed straight tubing. Since a 3" elbow tends to be heavy, I add a brace.
I don't recommend using an elbow that is just two straights joined together. There is a well known supplier of DIY gear who sells a port elbow that is basically this! There will be a large resistance to air flow due to the air having to make a drastic 90 degree turn, rather than a gradual bend. This loss in not present in a straight port.
You can use plumbing waste "solvent weld" fittings in some cases. Available in 32/40/50mm. At least in the 50mm size, they do some nicely swept bends.
Larger alternatives? 68mm or maybe 80mm UPVC downpipe and fittings.
J.
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