Rerurn to Romy the Cat's Site
In the Forum: Horn-Loaded Speakers
In the Thread: Canadian Speaker Proposal
Post Subject: "Parasitic sounds" and human perceptionPosted by haralanov on: 7/16/2013
fiogf49gjkf0d
 de charlus wrote: |
| Could you kindly elaborate upon what you mean by "parasitic sounds", as I am not familiar with this epithet. |
|
By "parasitic sounds" I mean all sounds which are contained in the signal
that are not part of the performed music. Different people call them with
different names – for example "alien sounds". These are all kind of audio
cracks when playing dirty LPs, all kind of digital front end distortions,
distorted recordings, distorting amplifiers and speaker drivers, distortion due
to bad electricity and many more. All those non-musically related sounds are
part of the signal flowing through the voice coils of the drivers and they
cannot be analyzed as a separate "parts". However this is only true if we are
analyzing the electrical signal itself. Right in the moment when the signal is
converted into acoustic waves, we have completely different situation. Now
these parasitic sounds can be perceived by the brain as completely separate
sounds that do not pollute the voice of the instruments. They exist with the
music, but in no way interfere with the music. I made an illustration to show
how the same signal (distorted audio signal in electrical domain) can be perceived
when reproduced by drivers of different quality:
Fig.1
visualizes what’s going on when you play good music having bad audio quality via
very bad speaker driver. The bad sounds are perceived as a part of the violin and
you cannot hear the voice of the violin any more – it is heavily polluted with
dirt.
Fig.3
represents what happens when you play the same music with the same quality of
the electrical signal, but this time reproduced by a very high quality driver.
You see – the bad sounds are there, but they do not affect the timbre of the
instrument, nor affect the value of the musical message. It helps the listener
to better understand the essence of the music.
Fig.4 shows
what happens when you reproduce the signal via ultra high performance driver.
Now the bad sounds of any kind are completely pushed away from the river where
the music is flowing. The parasitic sounds no longer draw attention to themselves - only the Music remains. You can even deliberately introduce heavy distortion of
high order (5th, 7th, 9th, 11th
order) in the signal and they will not affect the sound. It will be the same as you are listening live
music in the park and someone starts the engine of his motorcycle. The sound of
the engine could be irritating, but you can still easily perceive the music,
despite it is contaminated with noise. You just perceive the noise as
completely separate part of the complex acoustic interaction.
Best
regards,
Petar
Rerurn to Romy the Cat's Site