Both pipes make a solid impression. The "appearance" is dibasic. I have both risen. The NW30 is inevitably slightly wider and heavier than the NW20 and shrill in tone. With a volume measurement to get dba before both are overblown at 103 to 105 in the NW30 dba and in NW20. However, NW20 responding while blowing-off to the lower air pressure. Due to the smaller size and lower weight you will probably result in the northwest 20 more with constantly. As a "ladies model" I would I prefer the NW20. Well, both.
