Can you 'tune' more than one port for a single box to a different freqency, or will this cause some harmonic cancellation?
I studied music in college for 2 years, so I know all about harmonic distortion, consonance, and dissonance. I was just wondering if I could put three ports to the same speaker, maybe in a 3rd, and 5th interval from the first, and if it would sound good. for example, in the key of C using C as my base pitch (32.703Hz), then E (41.203Hz) then G (48.999Hz). Harmonically speaking these would sound good together if they were three seperately tuned boxes, but putting them all together could cause some distortion let's say when the pitch is at my base of 32.703Hz, I have my loudest tone because the driver and the port are in resonance. However I also have the two other ports at different frequencies, possibly causing some dissonance or cancelling the whole theory altogether.
Has anyone heard of this before, or am I running down a dead end street?
Replies (2)
Swez on 11/29/2003 22:49:16
Not at all... good topic... but multiple porting I have read about, had more to do with HIGH SPL vs smooth flowing bass of a "Daily Driver" application.
If you are looking to boost/balance certain frequencies, but avoid dissonace, DSP bass EQ makes much more sense than multi porting for car applications. There's some physics and acoustics laws in the mix here somewhere. How they interact, lots of math & modeling seem to be needed.
In general, it's about the phase angle of the tones as they interact together. How that all works.... need an Acoustical Engineer to sort this one out and then 10 guys to tell us what he said. I dunno...
Swez
cplkittle on 11/30/2003 04:37:21
thanks Swez.. I may do some experimentation with this.. will let everyone know what I find out. I had a premanufactured qlogic box several years back and I noticed that the ports were different sizes (lengths) didn't think much about it at the time, but that discovery has stuck with me and I am now curious about it.. I will have to reverse engineer that box to see what they did.
I studied music in college for 2 years, so I know all about harmonic distortion, consonance, and dissonance. I was just wondering if I could put three ports to the same speaker, maybe in a 3rd, and 5th interval from the first, and if it would sound good. for example, in the key of C using C as my base pitch (32.703Hz), then E (41.203Hz) then G (48.999Hz). Harmonically speaking these would sound good together if they were three seperately tuned boxes, but putting them all together could cause some distortion let's say when the pitch is at my base of 32.703Hz, I have my loudest tone because the driver and the port are in resonance. However I also have the two other ports at different frequencies, possibly causing some dissonance or cancelling the whole theory altogether.
Has anyone heard of this before, or am I running down a dead end street?
Replies (2)
Swez on 11/29/2003 22:49:16
Not at all... good topic... but multiple porting I have read about, had more to do with HIGH SPL vs smooth flowing bass of a "Daily Driver" application.
If you are looking to boost/balance certain frequencies, but avoid dissonace, DSP bass EQ makes much more sense than multi porting for car applications. There's some physics and acoustics laws in the mix here somewhere. How they interact, lots of math & modeling seem to be needed.
In general, it's about the phase angle of the tones as they interact together. How that all works.... need an Acoustical Engineer to sort this one out and then 10 guys to tell us what he said. I dunno...
Swez
cplkittle on 11/30/2003 04:37:21
thanks Swez.. I may do some experimentation with this.. will let everyone know what I find out. I had a premanufactured qlogic box several years back and I noticed that the ports were different sizes (lengths) didn't think much about it at the time, but that discovery has stuck with me and I am now curious about it.. I will have to reverse engineer that box to see what they did.
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