Live music

This evening as I was walking along 8th Street I realized that I was hearing live music. I looked around to see who might be singing and playing the guitar. There was a group of people sitting outside an entrance, and I looked over as I approached to see if one of them had a guitar. But no, they were just sitting around talking – no guitar and no singing.

But when I passed the entrance, I looked inside and saw it was a coffee shop. Way in the back was a guy singing into a microphone and playing his guitar to entertain the diners – not an uncommon sight. Mystery solved.

But then I got to thinking – how had I known it was live music, from clear up the block? The music I’d heard had travelled from the back of the coffee shop out into the street – I was still a good fifty feet up the sidewalk when I first heard it and realized I was hearing live music. And I hadn’t just suspected I was hearing live music, as opposed to a recording. I had been certain of it.

If the guy had been singing without an amp, it would have been easy to explain the difference. There’s all kinds of phase information in live audio that gets flattened, distorted or just plain lost when played back through a speaker. Humans are extremely good at detecting subtle textures in sound, and the difference between a live sound source and the poor substitute of playback through stereo speakers is quite dramatic.

But the guy I’d heard was singing into a microphone. I wasn’t hearing his voice and guitar directly – I was hearing music coming out of an amplifier and speaker. So why was it so obvious, even from all the way up the block, that I was hearing a live performance?

I have some theories, but I’m curious to know if anyone else has any thoughts on the subject.

5 Responses to “Live music”

  1. Brad says:

    I know exactly what you mean. There’s a quality to the sound of live music that comes through instantly. You need no clue but the sound. I’ve never thought much about how I can tell so quickly… I suspect it’s in the edges, the bass and the tenor.

    Intriguing- I’ll think more and am interested in what other’s think.

  2. Dennis says:

    Maybe some ambient sounds gets into the micphone or the reverberation is different.

  3. davidmaas says:

    It’s interesting to draw live performance recordings into the mix here, as recorded music is often impossibly clean… ie, each track recorded in “sterile” passes and balanced against each other. Live recordings have a completely different character, at least those that aren’t produced up the wazoo. Ambient sounds (as Dennis suggests) comes into play here, as does improvisational shifts away from the “sheet music” tact.
    And a live performance has yet another quality…
    I’ll go as far as to say that the human ear/mind is capable of detecting whether these improv tact shifts are synched with “now” – which is comprised of time and location. Another element may be the degree to which the various tonal areas carry and reverberate… shifts of tonal levels and how quickly they die out, that may even be more discernable from down the street than in front of the performer.

  4. admin says:

    Yes, these are all very reasonable theories.

    I suspect that the difference between hearing a miked performer live in a room and hearing a recording of a live performance is due to the fact that the performer is actually playing the entire room as an instrument.

    That instrument includes the sound that feeds back, after reverberating around the room, into the mike, and this sound is then reverbed back into the room, etc. While this happens, the performer is continually adjusting his/her performance to get the best sound (ie: using the reverb to add to the sound, but avoiding out-of-control feedback).

    We recognize that particular sound as live, because the only time we ever hear it is during a live performance. Note that a playback through an amp of a recorded live performance would sound different, because we’re not hearing it in the same room.

    There are some obvious ways to test this theory – particularly to assess the importance of the feedback into the mike of the sound that has dispersed into the room. A carefully controlled recording of a live performance, played back into the same room – alternately with/without a properly placed mike picking up the sound from the room and feeding it back out through the amp – might provide a test environment. We’d ask people who were not able to see into the room whether what they were hearing was a live performance.

  5. Dan Nielsen says:

    Although there are other factors that could have some subtle effect, as you said, that response cycle for amplified music sounds like a good bet, after considering some of the options.

    I ran across something nifty one day although the “I am Sitting in a Room” remake by Residuum follows a different sort of setup, because it doesn’t involve performer involvement, and the reverb is a filter set used to simulate a particular room.

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