I was actually making the same distinction but you are further confusing the issue by misunderstanding the reference to PA. It is useful to think of the audio system for recording and for amplifying the sound inside the theater as two separate but parallel systems even if they use the same mixer and mics. Also, let us not further confuse the use of amps and speakers required to get any sound out of an instrument like an electric guitar or the keyboards from the PA system to amplify the stage for the audience at a distance. You may mic the former to feed to the PA system but typically never mic the latter if you can help it, partly to avoid feedback if you are using the same system for recording and room PA (so there is no recording of a recording as you put it).
Think of those required electronics for some instruments as part of the instrument itself. Keeping these conceptual differences is key to understanding how audio engineering works for live performance or recording.
Talk of the PA system here is a red herring. Hypothetically, think of a live performance without ANY amplified audio inside the room that is good enough for an audience (other than any amps needed for electronic instruments which have no sound otherwise). Now, let us think of how to record it so it can be heard at home.
Basically, it boils down to how to mic it and how to mix it.
There are two different issues - how to capture the quality of the sound and ambience and how to represent the stage in terms of locating the listener relative to the stage. These are two separate issues. These have nothing to do with whether there was a PA system (for stage amplification different from instrument required transducers) in the location or not. This must be clearly understood before proceeding further.
Any mic positioning for recording is at best an approximation to the live performance. But you are not going to get a recording without mics. So, a whole part of audio engineering is to determine the position of the mics so that it captures the sound quality of various instruments and/or vocals. Think of this as just raw data before mixing. You can also mic to capture the ambience to input into the mix. So far, it has nothing to do with how many channels in recording output. These are all independent cables coming into the mixer from various positions and have no relation to the speaker channels at home yet. As I have mentioned, there are limitations to capturing the timbre and ambience of a performance perfectly but that is a given. These have nothing to do with if there was a PA system in the theater or not.
Now, once you have the raw feeds coming in, there is the question of how to mix it for the final output into a recording whether stereo, or multi-channel. But regardless of the latter, there was a discussion earlier of whether the position of the listener being represented in the recording is as being located in the audience or in the midst of the performers. This should not be confused with the other issue of quality of sound capture. You can use the exact same mic positioning and their raw feeds that gives the best quality you can get to mix it for either of those listener positions. You can do it in stereo or multi-channel for either.
My first point was that mixing the output from the perspective of a listener in the middle of the performance has no basis in reality of a listener being in the middle of a stage in a live performance. The latter in live performance is not good because of lack of balance between instruments on stage (with some exceptions as I have mentioned). So, you can create a virtual world from the raw feeds coming in and mix it as if the sounds were coming from all around you rather than in front of you. This is what some of the multi-channel SACDs do when they remix from original independent tracks even of a live performance. The goal here is never one of capturing the actual performance in terms of positioning even for a live performance for reasons mentioned above. Conceptually, they are not very different from some of the post-processing surround modes that try to approximate it from stere recording outputs.
Second, there is a misunderstanding that recording from an audience location perspective is to be done by recording what comes out of the PA system. In general, this is not true (with some exceptions for ambience or in budget/amateur gigs). It isn’t. It is created by mixing the same incoming mic feeds that are fed to the PA system if one exists. In budget/amateur settings, the two mixes might be the same but in most professional settings, it isn’t. The PA system isn’t typically just 2 speakers. The PA mixing goal here is to amplify the sound so that ideally it is as if the stage is playing louder to be heard in the audience NOT that the saxophone is moved to the left speaker. This is achieved via a combination of strategically placed speakers and mixing feeds in right proportions between them.
The mixing for recorded output from the audience position is conceptually different although it has the same goal as the PA system - to make the stage be heard as a stage in front of you. Just to be clear again, this is typically not done by mics in front of the PA system to capture what the audience is hearing except in budget/amateur productions.
If both are done correctly and professionally, the image of the stage projected with PA amplification in the performance is the same as the stage projected by the recording at home for a listener at the center of the audience (or wherever the mixing engineer’s reference point is), in reality a decent approximation. So from that perspective, it is capturing the live event as heard in the audience (but not by placing mics in front of the PA system, I keep repeating this because this seems to be misunderstood).
Multi-channel output capability can enhance either of the listening position reference points. In terms of the virtual world of being on stage to listen, it is almost a necessity. In terms of the reference point of being in the audience, it can be used to enhance ambience and the “live nature” in terms of audience presence if that is required.
Given that the reproduction of the concert hall/room is difficult, is it then then not better to concentrate on “on stage” mixings? Where the listener is surrounded by instruments, be it a real or artificial placement. This is then a new, non-comparable to live, recording. The loudspeakers carry less instruments and give them more weight.
There might be a misunderstanding of what a room curve is in the context of room correction. A room curve is not a room simulator of where the recording is. It is a term for a particular tonal balance of any speaker, typically a bit boosted in the lows and tapering down towards the high end to compensate for the effect the listening room on the relative hearing across the spectrum, in short to neutralize the listening room characteristics which typically absorbs more of the lows than the highs.And … this touches on the room curve too. I am still not sure (even after many posts) how a mix of traces containing signals from the audience-distance, with dispersion and reflections reducing higher frequencies, and traces with near-instruments microphones are finally mixed so that me as a consumer can add another room (either natural or Eqed) curve on top. The issue seems simpler with the “surrounded by instrument” mix, where the close-microphone trace can stay as is and the room curve will be added by my system (creating a “surrounded by instruments” field with dispersion and little reflections…)
Not necessarily. Getting a room feel is very easy and most hall-effect type post-processing modes do this fairly well. You can even simulate small room, large room, etc. The difficulty is not in the mixing for a location. It is placing the right type of mics in the right locations to capture the acoustic instruments and voices without getting affected by other instruments in the proximity, etc. Obviously, much easier for electric instruments since you already have the electrical signal. You have that problem regardless of what mixing you do. But you are correct in the sense that more channels you mix for, the easier it is for instrument separation. But many recordings done this way sound bad/artificial.
The main reason is that the mixing engineer has no control over how the multi-channel speakers are placed at home. Most common are HT configurations with side or rear surrounds. This configuration is actually bad for an immersive sound stage because in most home setups designed for HT, the distance between the mains and surrounds are too large and leave a huge gap say between L and SL or RL. Not a concern for HT because of the purpose for which the surrounds are used are different, not in equal terms with the mains and center. Moreover, the mixing engineer has no control over what this gap is since it varies a lot from home to home.
Some people who use multi-channel for only music place the “surrounds” at the sides ahead of the listening position in a way that is basically a semi wrap but in front. That has the advantage of wrapping the widened stage and the advantage of separating out the instruments without the spatial gaps of a HT set up. But this is not a common/standard enough configuration for a mixing engineer to use as a reference to mix for.
There might be a misunderstanding of what a room curve is in the context of room correction. A room curve is not a room simulator of where the recording is. It is a term for a particular tonal balance of any speaker, typically a bit boosted in the lows and tapering down towards the high end to compensate for the effect the listening room on the relative hearing across the spectrum, in short to neutralize the listening room characteristics which typically absorbs more of the lows than the highs.
What you are perhaps referring to is the room effect type of DSP processing added to the source content to create a performance room like atmosphere with reverbs and echos and delays. This is obtained by switching on that mode in your integrated amp or AVR or pre/pro with a DSP. Of course, a mixing engineer cannot assume that any such thing exists at the consumer’s end so if they think it necessary they add their own room effect. If they don’t, some people prefer listening to their music with a room effect turned on in their audio system but not all do.
And then, with immersive Mch, with all instruments recorded with near field microphones, things should be easier as no far field microphone gets in the way, and my room curve then compensates only for my room, probably making the instruments sound as they were 10 meter away from me. Unless the audio engineer added a room curve already to compensate for the bright sound he hears from his pure direct sound monitoring setup...
I assure you that treating early reflections is a Good Thing in all rooms where music is played:
Early Reflections
But there's more to room treatment than just absorbing reflections. You also need bass traps. This short article explains what acoustic treatment does, and why it's more important for quality sound than almost anything else:
Acoustic Basics
This explains even more, if you're really interested:
Bass Trap Myths
could you please clarify how did that annoying distortion sound?Your "Early Reflections" article swiftly uncovers the reasons for the painful discovery process I´ve gone through for several years to get rid of (personally) perceived annoying distortion, basically emerging from sidewall and in my case also tilted ceiling reflections!
It could be that, as you wrote, aging ears effects, or maybe also personal advances in listening capabilities, reveal them only later in life...
could you please clarify how did that annoying distortion sound?
Outsiders must think everyone in the US lives in places like the Trump mansion.I write this because after reading this post I am a bit lost. I just moved into a new apartment with quite a small living room according to US standard (17*14ft).
If this is a multipurpose room full of furnishings and such, there is no need to acoustically treat a room. Acoustically treating a room is most necessary for empty, dedicated rooms.If early reflections are a good thing and you should not treat them, then how do you acoustically treat a room ?
I'm really surprised to hear you say that, Amir. Have you never seen the response and ringing in an untreated room? My Early Reflections article above shows how terribly skewed mids and highs are when the specific reflection points aren't treated. And carpet addresses only one of those four locations. But bass problems are at least as damaging to sound quality. This is a typical bass response with and without bass traps in a room the size Lifer has:If this is a multipurpose room full of furnishings and such, there is no need to acoustically treat a room. Acoustically treating a room is most necessary for empty, dedicated rooms. If your room has a lot of hard surfaces without much damping material, then yes, putting a thick carpet on the floor is a good start.
Ok, acoustic room treatments then.
Room EQ is for people who cannot afford room treatments...better than nothing.
I assure you that treating early reflections is a Good Thing in all rooms where music is played:
Yes, unsophisticated listeners who aren't used to the clarity of reflection free listening might find the improvement unfamiliar and even jarring at first. But in the world of audio professionals - people who create and listen to music for a living - early reflections are not considered beneficial. I have visits from people who are both professional and lay, and everyone universally comments on the amazing clarity and overall excellent sound of my living room system which is very well treated.Dr. Floyd Toole often cites: that under conditions where loudspeakers are well behaved both on and off axis, early reflections can sound pleasant to many listeners by increasing ASW (apparent source width) and 'envelopment'.
Not at frequencies above transition. You are showing low frequencies in your graphs which are best dealt with using EQ. Absorption at low frequencies require very deep porous abosorbers due to large wavelengths that we are dealing with. Your graphs still show chewed up response even with the bass traps added. EQ is mandatory for smooth response. There is no getting around it.I'm really surprised to hear you say that, Amir. Have you never seen the response and ringing in an untreated room?
I would expect that on something called 'Audio Science Review', anecdotes don't rate. I also highly doubt that anyone would like listening in a room with 'no reflections'.