True, but in a straight TL the harmonics are in an odd multiple order.In a TQWT the harmonics are in an even order(closer together) which gives a greater LF response bandwidth.
Even though the TQWT will not go quite as low as a TL in frequency (given the same sound path length)i like the TQWT a bit better as the LF has a better response over a greater frequency range.
ron