Curt962 wrote:Wiz,Interesting concept. Yet what produces a <7hz signal? A Musician dropping dead in front of the Mic might make quite a "Thud", but beyond that?
... for example
Seriously:
Every percussion instrument produces subs.
Percussion is based on a single pulse, the hit on the instrument.
Physically a pulse contains all frequencies down to DC.
Vocal plosives in front of a mic are another example.
Electronic sound contains subs quite often, even more so if produced in the digital domain completely.
Remember the DC content discussion that led to introducing the DC Filter in ADI-2.
Several circumstances filter them, like the size and resonance of the instrument, the cutoff of microphone and, on purpose, the preamp etc., but never completely removes all sub low content (filters have limited steepness).
The DPA 4003 mic, commonly used for drums, percussion and as main mic for classical, is defined down to ~2 Hz e.g.
https://www.manualslib.com/manual/80008 … =12#manual
Curt962 wrote:Let me check my "Less than 10hz" Music collection....tc.,
Using an FFT Analyzer reveals a lot, you will be astonished.
Curt962 wrote: LF Trash isn't truly audible, steals power, and causes more problems than benefits.
Of course, this is why we try to remove them, usually on a per track basis during production, if their amount is significant.
My studio monitors reproduce subs enough to give me a warning sign.
Usually it’s a single event that I edit out.
Curt962 wrote: Reminiscent in fact of the 90khz harmonics that many Audiophiles "claim" to hear. tc.,
But this time the signal is not outside humans ability to perceive, if you speakers system is capable to reproduce it.
Curt962 wrote:I'm calling BS on this matter, as the Greatest Mastering Engineer to have ever walked the Earth (Robert "Bob" Ludwig) would have never allowed such Distortion-Producing infrasonic elements in his Award Winning works.
This is why we try to remove it.
For vinyl e.g. subs are an absolute no-go, remember the famous Overture 1812 recording where the canon shots can throw the pickup out of the groove.
It’s sold a lot of copies only for that “feature”
Here’s a microscope foto of the groove: