[Arctos]

Greetings,
Anyone know where I can get a pair of 3.5" port tubes?  I hope to get something that is flared on atleast 1 end and is atleast 8" in length.

The reason I would like to find something this size is that the speakers I am building would require a 4" tube that would be about 10" which puts the inside end too close to the baffle.  If I go with a 3" tube my speaker building program tells me that I will get port noise.  I have already considered going with 2 ports per speaker, but don't want to complicate things if I don't have to.

Thanks,

Arc

[mcgsxr]

Have you considered a rectangular port?  You could build it off one of the walls of the enclosure, and then you should have no problems with length, AND you can make the aperature large enough to avoid whistling - we did this with my friend's speakers, and it worked well for us.

Not sure if it is appropriate for you, but it is a thought.

[_scotty_]

Arctos, you could use a 4in. PVC pipe with an elbow it to keep the end away from the back wall or use a simple slot shaped  hole in the front of the box and radius the edge of the slot on the outside.  Your program should be able to give you the area of the slot to achieve the same tuning frequency and avoid
chuffing noises. Scotty

[Arctos]

Thanks for the ideas!!
I am concerned that a rectangular port may create some weird effects due to the square corners, but I will look into it.  I considered an elbow as well, but am most interested in Scotty's idea about the slot on the baffle.  I have seen this on some very nice speakers (Meadowlark, etc), though most of them are transmission line speakers if I remember correctly.  My biggest concern with this idea is that I will not be able to experiment with port length with this design.  Once you cut it you are done.

Regards,

Arc

[JohnR]

I have a theory (ahem ahem) that a slot is good because all the port energy is coupled to the floor.

Having said that, this port might work for you:

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=260-389

[mcgsxr]

To couple all the energy John, would the slot need to be on the bottom of the cabinet?

[Arctos]

Thanks John,
I did see that one at Parts Express, but was hoping to get something with flares on atleast 1 end.  I suppose the flared ends may not make that much of a difference, as many high end speakers come with ports with no flares.

Regards,

Arc

[JohnR]

To couple all the energy John, would the slot need to be on the bottom of the cabinet?

Yep