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In Reply to: RE: that brings up more questions??? posted by cloudwalker on August 14, 2014 at 17:13:04
The answer is incredibly easy - take a very simple case, A single Cello playing in a room for you. (My Niece was just in a recital this past weekend.) The sounds produced by the cello emanate form all over instrument - the front, the back, the bridge, & strings, of course.
The acoustics radiate outward into the room - are reflected by the various surfaces and combine in a completely non phase coherent way at your ears. Then the fun stuff happens. Your ears convert the waveform into a arbitrarily sampled god-zillion different neural impulses - that combined with visual clues - assuming your eyes are open - that the brain processes into an event that moves us with the emotion in the music and the real time experience of the performance.In stereo (or multi-channel) reproduction the waveforms from pressure variations in the room are recorded mostly with directional microphones (omni's would be better perhaps - another discussion) at discrete positions in the room. In the production - those signals are blended into the two or more signals making up the recording. Heyser called this process "Apodization" - literally "Removing the Foot" - or foundation of the live event.
In playback, we take those two somewhat correlated voltage signals, amplify them without too much alteration, directed then to some kind of loudspeaker that further distorts the signal - in space, time and frequency. By the time it begins producing its pressure variations into a room with a completely different characterization (visually and acoustically), there is absolutely very little resemblance to any of the recorded tracks - let alone the waveform of pressure variations that occurred at your ears.
We sit in out listening chair - perhaps to a Klipschorn or WATT or Quad, or 35 year old twice re-coned Advent - and our brain works the magic, trying, and often succeeding to fool us into imagining a live performance.
It is a miracle it works at all...
Three most important things in Audio reproduction: Keep the noise levels low, the power high and the room diffuse.
Edits: 08/15/14 08/15/14 08/15/14 08/15/14Follow Ups:
I made the same basic point in my reply to your earlier thread "Relevant loudspeaker tests" about 5 weeks ago. See http://www.audioasylum.com/audio/speakers/messages/33/335392.html. For convenience, here it is:
"Rooms and loudspeakers are only part of the problem. Musical instruments and microphones are two other parts of it.
With current "practical" technology, we cannot reproduce a musical instrument sound via a recording and subsequent reproduction system. It cannot happen.
Start with the source - a musical instrument. The sound is different at every position around the instrument. This sound is radiated into a room, which imparts its own aural signature. Couple that with the fact that every instrument has a different radiation pattern.
A microphone only picks up the direct sound of the instrument from one point in space, and picks up the room ambient sound, and imparts its own signature due to frequency-dependent and other characteristics. This then is "reproduced" through a single point via a loudspeaker which has a singular radiation pattern, and re-radiates the single-point sound into another room!
Given this, it's amazing that stereo systems sound as good as they do - even if they don't sound like real instruments!"
***
As a follow-up, as long as we're back on this topic, some people misunderstood my use of the phrase "single point via a loudspeaker" in that post. The microphone which picks up the sound is a single point in the room (unless someone wants to nit-pick microphone diaphragm size - which DOES matter, but not for this dicussion).
What I was referring to with regard to the loudspeaker was the loudspeaker location - i.e., a "single location", as opposed to emanating from the entire room, not specifically a particular type of speaker or "point source" speaker. I would have thought that everyone here would have understood that, and hope this clears up any misunderstanding.
This simple fact that a microphone captures direct instrument sound at only one point around the instrument, and also picks up the room's ambient sound (which has the room's sonic characteristics) from a multitude of directions, AND imparts its own sonic signature due to its directional characteristics which vary with frequency, AND its own tailored on-axis curve, and crushes it all together to be "reproduced" from a SINGLE LOCATION VIA A LOUDSPEAKER in the room, which has a singular fixed radiation pattern which does not vary based on the instrument being reproduced, renders futile any attempt to make a cello sound like a real cello, or a trumpet sound like a real trumpet.
Back to the OP's original question:
"Some of us look for speakers that excel at reproducing certain types of instruments or sounds in music. Which ones?"
Rock 'n rollers seem to prefer "boom-sizzle".
:)
I never posted "relevant loudspeaker tests" must have me mixed up with someone else. I did ask several questions more than once in this post..yet you seem to think I need to know something else. And you seem to think what you say is an absolute fact. Somewhere in this post someone said "live performances sound better". That is my experience too. All I want to know is why? I am here to pick up ideas to make my system sound better. I think there are no more easy improvements. It sounds amazing to me every time I listen to it. Thanks for your help...
Cloudwalker, my post in this thread was in reply to BigGuyInAtl, wherein he described some of what I had already posted in his thread "Relevant loudspeaker tests" five weeks ago. I felt it was worth referencing and elaborating upon. If you read it, you'll understand.
I read your answer many times...are you sure you were responding to my question? if you were there is 1 thing I still don't understand. In many live performances the sounds we hear have usually been amplified and played through speakers. At least this is what I am thinking about. Very little of the sounds we hear is unamplified. Why does what we hear often sound better than recording that same original sound and playing it back? They both use the same microphones and mic placements. And if played outside there is no reflected sound..
OK, I understand my confusion and mis-answer :))
Given that part I have to disagree, It's been a while since a live PA performance matched the sound quality of a home playback system.
An electronic instrument (keyboard, Guitar) weally has a hard time competing with an acoustic instument, directly. However, you can't get an acoustic equivalent of a Jimmy Page Guitar. He sound so much better in my listening room compared to the last Zep Concert I enjoyed.
Three most important things in Audio reproduction: Keep the noise levels low, the power high and the room diffuse.
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