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FYI on adding port length to Epic CF Series


avguytx
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This may already be carnal knowledge but I found that the best fitting tubes for adding length to the Epic CF-3's and 4's is going to your friendly carpet store. They have multiples of sizes of cardboard tubes from rolls that are sometimes 1/4" thickness and fit the thin stock plastic ports tight and snug. Did I mention they were free of charge? Once you get the desired length, just get a dollar can of black spray paint and you're done. So, now my 3's are re-braced, have new caps, resistors and 5.5" port tubes and, if I want to experiment with tuning, I can get more free of charge. I also have a port tuning generator from my car audio days that we used for tuning vented enclosures that will come in handy.

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if your new port tube walls are 1/4" thick then you will want to make the new ports longer to make up for the lost volume. Best regards Moray James.

PS: you can play with rolled up heavy paper and some tape to experiment with various tube lengths to see which works best for you they sound great take no time and are super easy to do.

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I wouldn't see where the 1/4" walls on port tubes would have an adverse affect on cabinet volume versus adding multiple wall braces internally. There's next to nothing in the calculated volume in the space that 2 small ports would take up. That would also be like saying that the added "dynamat" to the horns takes up a lot of space. Ports optimally still need to be solid like cabinet walls for no flexing.

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I was not talking about cabinet volume avguytx, you miss the point. The concern is with the internal vent volume as that is what you are tuning with (a volume of air acting as a resonant mass, more volume/mass will lower the tuning frequency and the reverse is obvious) a thin wall tube will have more internal volume (for a given length) than a thick wall tube. It's not going to be a huge difference I simply wanted to point it out. That way if people want to keep things the same (tuning frequency wise) then they can make the tube a little longer or shorter as required and the new vents will resonate at the same frequency as the factory ones.

Like I said before if you do all this with paper tubes it is a very simple and fast thing to do you can easily and quickly experiment with a wide range of new vent lengths for next to nothing then decide which length you like best and install that in a nice heavy tube. Best regards Moray James.

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Ok...gotcha. The inside dimensions of the ports remained the same as they were before as the new tubes just slipped over the existing plastic ports. Believe me, I do have knowledge in cabinet construction and tuning with round, slotted, rectangular, etc ports plus as aperiodic membranes, etc. 30 years of car and home audio did that for me. Plus, I own a Rockford OSC2 tone generator and have access to an Audio Control SA3050a analyzer if I really want to get jiggy. Lol

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no worries, I mentioned it just to make sure and so others reading will take pause to consider it. If someone is more concerned with finding a new port tube that fits the existing hole size they need to make adjustments to the vent length if the I.D. is much different from the original vent. Best regards Moray James.

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