no. they act like a 6th order bandpass with the woofer on the outside. they act alot like ABC boxes!
OK. have a small 1st chamber, this restricts higher freqs (it is ported around 40-50 hz)
Next chamber, moderate volume, tuned low with a huge port that should* be long.
last chamber, smaller volume, but not as small as the 1st. and ported around 40-50 hz.
* calculate all ports as the same size, and subtract the length of the high tuned port from the length of the low tuned port. now find what the low tuned chamber would be tuned to with that size port, and make it somewhat smaller.
LIKE I SAID, ITS EXACTLY LIKE A 6TH ORDER SERIES-TUNED BANDPASS!