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Old 23rd March 2019
Lives for gear

Anyone who has ever attempted to design helmholtz resonators will be able to see that not all ports are created equal. In the most basic terms: a smaller box with a smaller hole will ring more than a larger box with a larger hole (A smaller hole drops the resonant frequency of a box and increases the 'Q'). This is easily measurable and audible. I stand to be corrected here but basically the larger the box of a speaker and the bigger the port, the less the port is doing to fortify the bottom end of the speaker. I know for instance that with my atc scm50asl I lose maybe 1db-2db gain at the cutoff frequency by bunging the ports. The ports in this case are used more for driver loading than extending the frequency response. They are hardly ringing and I certainly don't find the bass to be 'one note'

Originally Posted by ilalin View Post
I respectfully disagree.
When talking about 'ports' I mean the so called 'bass reflex' system where vents are used to increase the perceived frequency response down to 50Hz so that small speakers sound beefier.
From what I learned, the problem is that this type of porting does help extend the frequency response down to 50Hz but beyond the response drops down steeply. So, a bass note that is moving around this spectrum will have an uneven perceived volume response. This makes it much harder to judge and obtain a solid and even bass line.
This would be a big 'NO' in electronic music employing sub-bass or certain instruments that go down to 20Hz like pianos and organs. In other words, a kick bass' energy in the 30Hz region might be 12dB lower than the 50Hz region, therefore making it a complete mess when the mix is listened in a different mixing environment.
Some other porting anomalies include, resonant frequency which a test signal will not show because it is different than music waveforms or percussive sound with fast transients, or ringing of the port that can cover a fundamental frequency. Furthermore, the port can resonate at various frequencies causing smearing and artifacts along the whole frequency spectrum not just low ones.
In my opinion, for serious mixing, it is better to have non-ported monitors coupled with the sub and a treated room not only with acoustic foam but bass traps also.
Now, this is expensive, but well worth the investment, if this is a business you're relying on.
A good example is the timeless popularity of Yamaha NS10's which are not ported. Of course, it is impossible to judge the bass just using these but the midrange comes in focus amazingly well due to less above mentioned artifacts. As Bob Katz would say after all: 'Midrange is the key'