Cello with piano accompany in Church

[Drew Stephenson]

really a newby question: What does 90 degree off axis look like? If I am holding the mics in front of the player, instead of pointing the mics to the cello (in the front), left mic pointing to left and right mic pointing to the right?

Isn’t it just 20 degrees less than an ORTF pair? Should look like a shallow ORTF?

We're not talking about the stereo capture side of things here but the pressure build up at the capsule. If you're using omni's then ORTF isn't a thing, nor is anything else that relies on the directional properties of the capsule. The off-axis suggestion here is to manage the effect of HF build up.
Hugh's thread that James linked to above covers it.

[Arpangel]

really a newby question: What does 90 degree off axis look like? If I am holding the mics in front of the player, instead of pointing the mics to the cello (in the front), left mic pointing to left and right mic pointing to the right?

Isn’t it just 20 degrees less than an ORTF pair? Should look like a shallow ORTF?

We're not talking about the stereo capture side of things here but the pressure build up at the capsule. If you're using omni's then ORTF isn't a thing, nor is anything else that relies on the directional properties of the capsule. The off-axis suggestion here is to manage the effect of HF build up.
Hugh's thread that James linked to above covers it.

I’m just talking about how it looks.

[Drew Stephenson]

It looks like two microphones, 30 cm apart, standing vertically upright.
Not really like ORTF at all.

[Arpangel]

It looks like two microphones, 30 cm apart, standing vertically upright.
Not really like ORTF at all.

That’s weird, whenever we’ve used spaced omni's on piano we point them directly at it, I know they’re omni's but?

[Bob Bickerton]

It looks like two microphones, 30 cm apart, standing vertically upright.
Not really like ORTF at all.

That’s weird, whenever we’ve used spaced omni's on piano we point them directly at it, I know they’re omni's but?

Depends on the microphone. They’re either designed for use in the free-field, that is fairly close miked or in the diffuse-field, that is to be used further away from source. My MKH8020s are designed flat for use in the free-field, so I’d point them at a piano if miking fairly close, I used to use my KM183s 90degrees off axis at a similar position because they’re designed for the diffuse-field (and have a HF boost). Your MKH20s have a switch to enable either option!

Best read the link to Hugh’s post above.

Bob

[Drew Stephenson]

What Bob said.

Also a lot of omnis are not completely omni at higher frequencies so there will be some directionality involved there as well.
As usual, experimentation is the name of the game to get the best sound for those instruments, in that room, at that time.

[Hugh Robjohns]

I find it disturbing how few people seem to know about, let alone understand, the practical sigificance of diffuse- / free-field equalisation on omni mics.

This key aspect of omni mics was discussed in this month's Q&A column in the magazine.

https://www.soundonsound.com/sound-advi ... icrophones

If you only have omni mics equalised for the diffuse field (with a hefty HF boost), but need to use them in the near (free) field, then the solution is as Bob describes: place the capsule so that the direct sound passes across the diaphragm instead of straight into it. This avoids any pressure build up in front of the diaphragm and thus negates the audible HF boost completely.

In practice, that means rigging the omni mics so they point at the ceiling rather than directly at the instrument itself.

As for the OP's recording session if I was doing the job, I'd arrange the cellist opposite the curve of the grand piano, maybe 3 metres away and facing the pianist for good eye contact and acoustic separation.

As an evaluation recording (rather than a concert CD) I'd err towards individual spot miking rather than an overall stereo pair.

How you mic it depends on what mics you have. I like ribbons on strings, so I'd rig one or two ribbons for the cello, placed side-on to the piano (for max rejection), and then a couple of mics for the piano looking in from the tail (Decca style,) or in the curve looking down.

If you have cardioids for the cello, then aim with the null backing the piano and turn the cellist to face the piano.

If the room warrants it, you could add an ambient space pair to help the (closer) instrument mics blend better.

[MOF]

The OP has two microphones Hugh. It’s been interesting to find out about the different omni microphones, I didn’t know about the hf lift.

[Hugh Robjohns]

Ah... Sorry.

In that case, I'd place the cellist a couple of metres away from the curve of the grand piano, facing the pianist or good sightlines, as before. Rig the omnis on a stereo bar about 30-40cm apart, facing the ceiling, and place the stand roughly midway between the piano and cellist. Start maybe 1.5-2 metres high and experiment with height and position to optimise balance and tonality of cello/piano.

as a starting point, the mic towards the keyboard end of the piano should probably be panned left, and the one towards the tail panned right... but depending on distances it might not make a lot of difference which way round they are, and you might choose to favour the cello in determining the mic panning (high strings right).

As it's a demo piece for the cellist, I'd definitely favour the cello clarity over that of the piano.

With the right positioning you should end up with a reasonably narrow (but not pencil thin) cello image, and wider piano image, with the church acoustic filling in the edges.

[stany]

This is exactly the use case that got me started in recording and videography as a hobby a couple of years ago--my cellist daughter is finishing high school and is preparing for her auditions, and her pianist brother is her sonata and chamber music partner. Lots of good ideas here for me to try out, many thanks! I have an R88, an omni pair, and a cardioid pair, so nearly everything described is possible.

One thought--facing each other could have micing benefits, but since video is usually required for screening recordings, I plan to do this with a live-performance stage setup since that's what the screening committees will be most familiar with.