This may sound ridiculous but....
For several years of working on different subwoofer projects I've noticed what seems like a draft in the room while playing music with low frequency material. It registered in my mind but since my listening is often in the basement I dismissed it as a draft in the room. The other night I experienced it again and this time stopped and started the music and changed selections back and forth. Sure enough some material does excite the room in a way to produce what feels like a draft.
One recording in particular (I'm sure some of you will hate and disregard as garbage) is Kenye West "Monster".
Has anyone else experienced this?
Do you think the producers know it's happening?
How can it be deliberately reproduced and controlled?
Scott
For several years of working on different subwoofer projects I've noticed what seems like a draft in the room while playing music with low frequency material. It registered in my mind but since my listening is often in the basement I dismissed it as a draft in the room. The other night I experienced it again and this time stopped and started the music and changed selections back and forth. Sure enough some material does excite the room in a way to produce what feels like a draft.
One recording in particular (I'm sure some of you will hate and disregard as garbage) is Kenye West "Monster".
Has anyone else experienced this?
Do you think the producers know it's happening?
How can it be deliberately reproduced and controlled?
Scott
No, never had that problem, i use open baffle sub, four 15".
Never heard kenye, i hope i never will.
However, when i set eq flat to 20Hz, and play loud, bach, organ music, or other classical with full orchestra, things start to rattle and vibrate and move...
Never heard kenye, i hope i never will.
However, when i set eq flat to 20Hz, and play loud, bach, organ music, or other classical with full orchestra, things start to rattle and vibrate and move...
I once forgot to high pass my B&W 805’s and with 200 watts on them the front facing ports were flapping my friends pants.
Can you provide some measurements? A child's windmill on a stick should be a good enough instrument to give sufficiently accurate data.
Attachments
Scott,
Polarity asymmetric waveforms are common in many acoustical instruments, and can produce a "draft" with low frequency content.
1) Yes, as well as the waveform itself causing a net "direction" to airflow, speaker suspension may be stiffer in one direction than the other, causing the speaker to act like an air pump even with symmetrical wave forms.
2) To some extent, yes- there are a lot of engineers that like to see cone movement so remove grill cloths on studio monitors, a producer certainly could associate certain sounds to cone movement.
3) In general, the asymmetric waveforms in music tend to "even out" due to room reflections, combined instrumentation, etc.
Various synthesized sounds may already be very asymmetric. Distortion can be used to accentuate asymmetric waveforms further. If you wanted to deliberately turn your speaker into a fan, you could specifically raise the content of low frequency asymmetric waveforms in the mix. Many digital recording programs allow viewing waveform samples, an individual waveform the shape of a particular note or drum beat can be duplicated and inserted at will, just like "copy" and "paste" in a word processor. Find the waveform that "blows", repeat ad nauseum ;^).
Art
I have noticed with a small subwoofer port on a 2:1 system for a PC that it was possible to make a draught that would keep a small childs windmill in motion.
The windmill needed to be kept a distance away from the port. Too close and it would stall.
I eventually came to the conclusion that the positive pressure out of the port had a directional flow, while the vacuumn caused by the negative pressure cycle in the box would cause the atmospheric pressure to enter the port from all directions.
The windmill needed to be kept a distance away from the port. Too close and it would stall.
I eventually came to the conclusion that the positive pressure out of the port had a directional flow, while the vacuumn caused by the negative pressure cycle in the box would cause the atmospheric pressure to enter the port from all directions.
Just to clarify, the tactile experience I mention is not typical "bass hit" you feel in your pants or gut or port air movement. This actually feels like a gentle air circulation around the room lightly felt all over my body.
The frequency would be very low. I might be able to find some very light paper and suspend it on thread to see the air current.
The frequency would be very low. I might be able to find some very light paper and suspend it on thread to see the air current.
That's interesting, if true, are you sure the windmill is bi-directional?
I'd like to see that too, I can imagine it could feel quite nice
I've felt something similar now and again to your bass winds (and not just after eating too many beans), but I don't believe it to be an actual draft. My best guess at it (after observing what happens and playing with the levels) is that it's the finer hairs on the body starting to vibrate as they do when getting to the point of "pants flapping bass", but just on the edge of perception such that the brain tends to interpret the feeling as a draft just as an actual draft would be detected by a similar mechanism.
I make Bass amplifiers and very often I feel winds and pant flapping when customers test their stuff loud.
Breeze-in-my-hair never happens in my sealed-box woofer experience but others swear it does. So what might be theoretically be the cause?
Hard to imagine there's much asymmetry to the speaker motions.
The notion that positive port air is directional vector and negative port air is non-directional sounds plausible. For sure, there must be lots of badly designed ports that behave like air-blowers out there. But would that apply to the 15-inch cone?
And how about the phase of the port relative to the cone? They are opposite below speaker resonance although that's where the biggest cone pulsation takes place. So testing at a frequency just above the port tuning where the phases match (need I add, "boom"?) might be revealing.
B.
Hard to imagine there's much asymmetry to the speaker motions.
The notion that positive port air is directional vector and negative port air is non-directional sounds plausible. For sure, there must be lots of badly designed ports that behave like air-blowers out there. But would that apply to the 15-inch cone?
And how about the phase of the port relative to the cone? They are opposite below speaker resonance although that's where the biggest cone pulsation takes place. So testing at a frequency just above the port tuning where the phases match (need I add, "boom"?) might be revealing.
B.
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