I have been sampling pipe organs for fifteen years and have recorded thousands of pipes in many organs. Here is a how-to that I put together a while back for capturing theatre organ ranks and percussion. TPOs are, IMO, more difficult to sample compared with classical instruments, but the same general principles apply to both (for dry sampling). For wet sampling classical organs, the mics would be centered perhaps ten or twenty percent of the distance from the pipework and left in a fixed position and spaced three to six meters apart, rather like recording an audio CD. There are other paradigms, but this would give you a good start. Specific hardware is mention as examples, not an exclusive list.
Mic Type:
- Best: quality small diaphragm condenser with Omni, eg. Rode NT55, Earthworks TC20, QCT-40MP
Next best: large diaphragm condenser, eg. AKG 414 BULS
Good: Zoom H4n (handheld recorder with 2 mics, street price $299)
Stereo mic placement:
- Less than one meter from fully opened shades, approx. three meters apart. I do not recommend placing mics inside pipe chambers.
Recorder:
- Best: straight into PC thru pro quality 24/96 phantom powered audio card
Good: Zoom H4n, in 24bit / 48 KHz PCM mode (never mp3)
Recording specifics:
- Important: set levels with just background noise, no pipes sounding. Then play a chord around middle C using a soft rank such as Quintadena. There should be a difference of 30 dB or better. If not, it may be a waste of time to continue.
The biggest mistake is to clip (overdrive) the recording. Leave plenty of headroom. Often the mic preamp is overdriven. Set 10db pad switch to On if available. 10db pad attachments are available which are inserted between cable and mic. The loudest ranks are Post Horn, Solo Tibia, Trumpet and sometimes diaphones. Set levels for the loudest pipe, then leave alone for all other pipes and ranks.
Close shades of chamber(s) not being recorded.
Muffle noisy trems if possible without affecting their action.
Patch any wind leaks if possible.
Use only the one trem needed for the rank being recorded.
For pipes, record 10 seconds note on, then 5 full seconds note off for every pipe, repeat with trem on.
For tuned percussions: allow 5 seconds after each note decays to inaudibility (especially with chimes).
For reiterating TPs: record 10 seconds with re-it on, and then allow five seconds after each note off.
Tuning is not important, it can be corrected later.
Record all pipes, even if badly voiced.
The real work of sampling is done after the recordings are made, specifically extracting noise, trimming, looping and so forth. To do this well generally requires a considerable amount of patience and experience.
Good luck,
Joe Hardy