[Ardour-Users] Live Recording Techniques

[Justin M. Streiner]

On Tue, 21 Jul 2009, Ralf Mardorf wrote:

> Justin M. Streiner wrote:
>>  If possible, set up an ambient mic or two some distance away from the
>>  choir, if logistics and room space permit.  That's often a much more
>>  affective way to get some of the room acoustics
>
> If it's a high room and you have the right tripods use 2 overhead mics. I 
> once watched Al Schmitt recording an orchestra. I was impressed because of 
> the good reverb, he laughed and told me, that he didn't add reverb, but he 
> had 2 overheads, that recorded the room. If you can't do overhead mics, but 
> as Justin told you, "distanced mics", take care not to record too much sonic 
> that is reflected from the floor. Maybe you can do a sound check before you 
> do the recording, take care that you won't get troubles because of phases, 
> e.g. check if nothing will be eliminated when you listen to mono.
>
> !!! You should record ambience this way, but do it on separated tracks, so 
> you can chose later to add it or not.

All good points.  Distant mics can add a lot to a recording, especially 
if it's in a room with good 'big room' acoustics, like a cathedral or a 
music hall.  There are caveats about:
mic type - I tend to favor small to medium diaphragm condensers or ribbon
   mics for something like this.
polar pattern - omnidirectional mics can be used, with _great_ care;
   cardioid or supercardioid mics will minimize the number of reflections
   you have to deal with.
frequency response - the farther the mics are from the sound source, the
   more low and mid-range frequencies can start to dominate the sound.
placement - stay away from hard surfaces (including floors and ceilings)
   if possible, to minimize unwanted reflections, standing waves and
   phasing issues, as Ralf mentioned.  Another variant is using mics that
   are placed on or near the stage, facing into the crowd, though the
   polarity of these tracks might need to be reversed to minimize phase
   cancellation.

If the live recording will be done in front of an audience, keep in mind 
that the acoustics of the room will change based on how many people are in 
the audience.  Soft objects (people and their clothing) tend to absorb 
sound, which can noticeably deaden the acoustics, compared to a soundcheck 
in an empty room.  Don't be afraid to experiment with different mics and 
placements, if time and circumstances permit.  As Ralf also mentioned, 
record the room mics on separate tracks in Ardour, so you can determine 
how much 'room' you want in the recording during the mix, and if you don't 
like the 'room' tracks at all, you can always mute/disable/delete them 
later.

My treatment of the subject here is somewhat simplistic.  Many books have 
been written about live recording techniques that go into much more detail 
about subjects like reflections and standing waves.

Hope this helps.

jms