place port on node?

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I'll go with no, as the Helmholtz resonance (that of the tuned cabinet, the internal airload acting with the driver parameters) is not related to the standing waves inside the enclosure. So, you're not trying to increase the output of standing wave frequencies as your cabinet tuning is not this frequency, it's likely much lower.

I think an MLTL is sort of a hybrid of both though where this thinking may be relevant?
 
Try as I may, I've never gotten good results placing the driver's center at the ~1/3 line length in a TL. OTOH, I've always achieved the best results with the driver at ~20% (15-25% range). And, I've modeled by now hundreds of TLs both tapered and mass-loaded, plus built quite a few for personal use. The port's center can also be located at an optimum location relative to the line's length and the driver's location, and in an ML-TL it's most often a few inches from the opposite end of the line. Using accurate modeling software is a must, however.
Paul
 
Paul, re:'The port's center can also be located at an optimum location' - so what does 'optimium' mean here? maximum output from the port?

Answer: Nope, at least not IMO. The optimum location for the port results in the smoothest overall system response shape because it pushes port-induced glitches in the system response higher in frequency, allowing the crossover's roll-off to more effectively reduce their effects on mucking up the midrange. Locating the port for it to have a maximum output may be useful in some cases, like for a 3-way where the woofer is not going to be playing much, if at all, in the midrange area. Frankly, though, in all the modeling of ML-TLs I've done, I've never found moving the port has had much effect on its output and, thus, the low-end system output. YMMV, however.
Paul
 
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