Phase alignment for acoustic guitars - mixing 2 stereo mics, and K&K trinity pro (transducer+mic)

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I've been recently trying out recording with my 2 stereo mics, and also my K&K Matrix trinity pro (transducers and Mic)
I'm finding I need to add 46 and 49 samples to the pickup and inner mic to get them roughly in time, then one of them needs a 180 degree inversion.
tbh I'm not sure this is a great way to do this, never really tried before
Am I really adding anything useful, and am I damaging too much by mixing these sources?

Experiences / advice please


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Comments

  • FunkfingersFunkfingers Frets: 14323
    my 2 stereo mics
    Is that stereo as in a matched pair or as in two capsules per shell? (i.e. Four capsules altogether.)

    In the latter case, the relative positions of the capsules and switchable pick-up/rejection pattern options will effect what arrives at the mixer.

    K&K Matrix trinity pro (transducers and Mic). I'm finding I need to add 46 and 49 samples to the pickup and inner mic to get them roughly in time, then one of them needs a 180 degree inversion.

    According to the manual, there is a 180 degree phase reversal switch on the black box.  http://kksound.com/products/trinitypro.php Unfortunately, it fails to make clear which signal is having its phase reversed with respect to what else. Try it anyway.

    Considering that the transducer elements respond to the physical vibrations of the soundboard whereas the gooseneck mic responds to the air moved by the vibrating soundboard, there ought to be a fractional delay. If there is a simple summing mixer inside the electronics box, this could introduce a processing delay.
    Be seeing you.
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  • ToneControlToneControl Frets: 11789
    edited December 2017
    the mics are a sontronics STC-1 matched pair, they work very well together

    the switch in the K+K mixer box is just to reverse the phase of the mic relative to the transducers

    The in-guitar mic responds first, then the transducer
    the mics about 10 or 12 inches away respond around 48 samples later, which is about 1ms

    I just noticed that both the K+K channels are out of phase with the mics. I have now time-aligned them, and brought back into phase: sounds much richer
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  • FunkfingersFunkfingers Frets: 14323
    the switch in the K+K mixer box is just to reverse the phase of the mic relative to the transducers

    I just noticed that both the K+K channels are out of phase with the mics. 
    Since the K+K electronics are pretty much fixed, it would be conventional to reverse the phase of the microphone signals on their mixer channels.

    Time aligning after the fact is one way to achieve signal coherence. Alternatively, make a feature of the timing difference by creative use of panning.
    Be seeing you.
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  • StuckfastStuckfast Frets: 2393
    This really is a classic case of "if it sounds right, it is right".

    But be sure to check in mono.
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  • mellowsunmellowsun Frets: 2422
    Sounds like you have too much going on with effectively 3 mics plus transducer.

    Have you tried with a single mono mic plus the transducer only?
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  • My 2p is that you have to go some way for a tranducer arrangement to beat a stereo mic setup (for natural sounding recording). First thought is that the transducer arrangement is for live.

    Been experimenting with mics recently. I get more done when things are simpler...so, two mics or just one...depending on application. Maybe you want a nice stereo solo acoustic sound...or maybe you’re burying something mono in the mix.
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  • ToneControlToneControl Frets: 11789
    mellowsun said:
    Sounds like you have too much going on with effectively 3 mics plus transducer.

    Have you tried with a single mono mic plus the transducer only?

    My 2p is that you have to go some way for a tranducer arrangement to beat a stereo mic setup (for natural sounding recording). First thought is that the transducer arrangement is for live.

    Been experimenting with mics recently. I get more done when things are simpler...so, two mics or just one...depending on application. Maybe you want a nice stereo solo acoustic sound...or maybe you’re burying something mono in the mix.

    I've just been recording with a stereo pair until now. Did try a stereo pair with a large mono mic too, not very happy with that.
    I wanted to see if adding these transducers and inner mic was useful

    So far the answer is - sounds awful unless you correct the time alignment, then you can work with it, and there is some extra sound in there, but as you guys say, simpler is probably better: I expect to probably stick with stereo mics
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  • Try Mid/side. Can produce some interesting results. 
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  • I've tried mixing sources. Never equates to the work put in for pop amd folk music. Prefer to record one mic in mono, a tube ldc and if using two sources have a sdc & small ribbon (se vr-1) right on top of each other to blend. 

    If you want that big stereo sound then a good sounding room and a stereo pair further away are normal. 
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