Paul's Posts — 27 October 2011
By Paul McGowan
In my post “Through and open window” I mentioned that if I am walking down the street and hear a piano through an open window I know immediately if that’s the sound of a real piano or a recorded one. Odd that we can do this even from affar and through a window.
I can also tell if someone is playing an electric instrument like a guitar live – and can identify this sound of the electric guitar through windows and over long distances through a neighborhood.
This is all very odd because in the case of the electric guitar, it isn’t a live acoustic instrument it’s actually not much different than our stereo systems – yet we always know if it’s live or recorded.
Or do we? Let’s try a thought experiment. If you have an electric instrument (let’s think guitar again) and you compare it being played live through its loudspeaker vs. recorded and then played through its loudspeaker, I’ll bet you can’t tell the difference. But if you take that same recording and play it back through another loudspeaker – even the best loudspeaker pair in the world – you will immediately be able to tell it’s not live.
So the loudspeakers are at fault? No, not entirely. Here’s what I suspect. The ear/brain is just sensitive enough to identify something not reproduced on the original final medium and whenever that happens, we immediately pick up the cues that tell us it’s not live. So it is the fact that something is altered when not reproduced on the identical instrument or reproducer.
Which brings up an interesting dilemma for us high-end types: if the problem is that the ear/brain can immediately pickup the difference between live on the original instrument vs. reproduced when not through the original instrument/medium, what hope do we have for high-end’s ultimate goal of recreating the sound of live music in our homes?
I think then the challenge is for someone to focus on this one critical area and uncover the secret. I’ll bet it’s not hard.
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audiofilodigital.com
Our sense of hearing is much more than only the frequency analyzer most people take it for. In a musical context, humans first perceive and interpret a pitchless noise (a so-called transient) followed by the actual note (a repeating vibration, frequency), so, 2 processes. In fact each natural tone is preceded by such a transient noise. It informs our sense of hearing about the location, type and size of the sound source, e. g. a danger around, or, mostly nowadays and for our HiEnd Audio applications, an instrument. If we had to wait until our ears detected and analyze the frequency, I am afraid that no one of us nor our relatives would be alive.
This matter has been discussed and even analyzed using the latest laser doppler techniques which show what some speakers do and how they react, and what others don´t do… beyond the frequency response, which is ok,… but not enough to understand how we hear and why we have been able to survive until now.
Have anyone realized for a while that we have an electronic signal (AC) that, at the end, must be turned in a mechanical movement that makes the air vibrate immediately ? And this only happens just at the end of the system (loudspeakers).
I would recommend to analyze and get to know how our ears mechanism work. Then get your own conclusions ‘though, without knowing how we perceive the sound (all the process) it’s almost impossible to understand how we must develop solutions to “trick” (satisfy?) our hearing capabilities.
Ballisticman
At the West End in Dallas I experienced some white noise AC/DC stepping right in front of the speaker bank about a generation ago. I was in the Dome when Dan dladden hit his Grand Slam against the SL Cards. The prevailing ad at the time was, “Is it real, or is it Memorex?”
I bought Memorex by the case…..
PastAudile
I’m not saying that all of the ordinary issues of fidelity of reproduction aren’t very important, things like undistorted dynamic range, and amplitude and time response across frequencies, but I think a major factor in this live vs. reproduced disconnect has to do with properly defining what the act of listening really is: Just like when you touch something it doesn’t stop with laying one finger down statically, the experience of listening includes the processes of passing your ears through the sound field with the full six degrees of freedom. You move around, even if only very subtly, to sample the soundscape. This occurs in the context of a lifetime of experience about what is “supposed” to happen as your head shifts around in the type of space you are in. Recreating this sound field accurately is probably an impossibility, but that doesn’t mean that we can’t get better at the illusion. An open widow emits a lot more information than just a radiating point source.
zrdc
I’m not an engineer, but my hunch is that live music, amplified or not, is something our brains recognize based on the interaction between the sound sources and the environment, the dynamics, frequency range, harmonics, distortion, etc. Recorded music cannot capture all of these elements perfectly. When the recording reproduces the acoustics of the original performance space, it’s immediately recognizable as “not live.” Only when the playback space has approximated the recording environment and when the recording has been miked extremely well have I ever thought, “This sounds live.” Solo and small-group acoustic music comes to mind. On the other hand, there have been many occasions during live concerts when I have been struck by the fact that my recordings of the same music sound better at home. Seating, venue acoustics, and sound board decisions often compromise the sound of live performances. In general, I’d rather have it sound “good” than “live.” Luckily, I get to define “good” and then try to create that for myself, and I’ve been pretty successful so far!
hifigeek1
I believe the human ear is able to determine if the sound is emanating from a point source or not. If it’s not coming from a point source such as a speaker with multiple frequency drivers with multiple locations on the baffle, group delay and it’s crossover phase distortions force the ear to perceive it as ‘not live’, i.e. from a speaker. When you see a guitar player playing through an amplifier, you SEE the performer playing. The brain makes up for the minor distortions. Remember a guitar amp has one or 2 drivers in it and not different sized drivers with crossovers. Therefore, no real phase distortions are present other than those caused by the drivers themselves.