Peevy wrote:Just wondering how you go about gain matching the Rode NT-SF1. I have a Zoom F8 for on location recording, so I would imagine that would work alright, but in my studio I don’t have four stepped gain or digital preamps. What would be the routine be for gain matching the capsules?
Yes, it is certainly an issue if you don't have preamps with a well defined gain adjustment system in place. The best I can offer is to acquire one of those plug-in XLRs that generates a mic-level test tone, and use that to align the four mic preamp channels to some suitable gain.
The process would be to adjust the gains of the four mic preamps during a rehearsal to achieve a sensible gain structure with plenty of headroom. Obviously, the capsules closest the loudest sources will produce more level than the others... so the idea is to look at the loudest output and set all the other preamps to the same gain by eye. Then disconnect the mic and plug the test tone generator into one preamp and note the meter reading. Then plug it into each of the other preamps in turn and fine-tune their gains to achieve exactly the same meter reading. And finally, replug the mic! That way you will have perfectly aligned preamp gains in all our channels, even if the gain controls end up pointing at slightly different places!
This ain't new rocket science, either... Some of the very early Calrec SoundField mics in the 70s had a built-in test oscillator precisely for this purpose, and it would have been sensible if the Rode (and other Ambisonic) mic(s) included a test oscillator to send the a reference level to all four outputs -- precisely so that you could align the gains of a independent variable-gain preamps... but they didn't... presumably to keep the cost down.
And actually, even if they did, with electret capsules it wouldn't be guaranteed to be accurate after a few years anyway as the capsules' sensitivities will inherently decrease over time and not necessarily all at the same rate...
Also, how do you work out the recording angles? … or is that not relevant with a mic such as this?
It is relevant in so far as the decoded outputs can emulate conventional coincident mic arrays, but you have the ability to change those arrays in post-production to suit the recording requirements. So you can change the decoded virtual mic polar patterns and mutual angles, which will alter the stereo recording angles after the event...
So rather than worrying too much about the stereo recording angles, it's actually more important to make sure the placement is optimised in terms of direct/reflected sound balance (although that will also vary to a degree as the emulated coincident arrays are adjusted).