I ve learned recently that if you run a condenser and a dynamic (or ribbon) as a coincident pair (for example on a guitar cab), they will be 90 degrees out of phase because of the different ways they generate electrical signals.I know it s common practice for Steve and others on this forum to mix the two, but does this cause any problems? Does using the same type of transducer generally give better focus or help with mono compatibility? Would love to hear your take on it.Mikey

Some out board gear is like this as well. I know PRE-Behringer bought Klark Teknik Compressors were pin 3 hot. never hurts to flip pol and give a listen anytime you are blending 2 signals to a single whatever.

yep. ears. also maybe ignore it all together. use combos of mics that work and don't try to fix when they don't. I'm totally down with people stopping looking at audio. I've had a bunch of arguments lately with folks about phase shifting when eq'ing and it's just stopping them form getting work done because they are looking at a phase readout instead of just listening to a room, but this is for live sound. still, I think it applies. 20 years ago the option was 180 degrees out or you left it alone, now people cant stop fucking with it.SMAART is fucking with peoples heads.

Steve's oscilloscope comment is spot on. Or even easier, if you're working in a digital platform you can just look at the waveforms. You can also slide them if you really need to.I combine all types of mics on guitar amps at various points and they've all played together well from a phase perspective. Sometimes going for equal spacing can take some consideration as the head basket on some mics is larger so the capsule is further away than it may appear. At the end of the day it's more about your ears than measuring millimeters.

Yeah, but he's saying 90 degrees out of phase, not 180.

There are some microphones that are of opposite polarity to the international standard (positive pressure on element or rearward movement of element producing positive voltage on pin 2 of the connector), but that is a specific problem to those microphones. I use dynamic and condenser mics in coincident placement all the time, and I often verify their positioning using an oscilloscope, so it is possible to get very good correlation between them. Higher frequency phase can be affected by internal acoustics, baffling, electronics and even passive components in the microphone, so there will always be some phase irregularity at high frequencies, but the fundamental sound can be brought into very good alignment.

This seems like if it was something of a problem there would've been a four position dial instead of a two position switch for phase correction installed on more outboard equipment.

Did you try aligning the two mics by inverting the polarity of one of them and then moving one with respect to the other for maximum cancellation?The DPA website is interesting because it s both very brief and very general. For example, there are pure pressure (i.e. omnidirectional) dynamics...the EV 635 for one. I d love to read more about that.

So, to test this out, I got two mics and ran them through the same preamp. I chose a Stedman N90 and a Josephson e22s because I can see where the capsules are on each. This made it easier to line them up. Putting them both very close to my studio monitor - I'm going to run a quick 500hz sine BLIP and look in my DAW to compare their waveforms.Here's the resulting screenshot:This may be a little tough to read, but it tells us enough. The top is one cycle of the DAW's 500hz tone, the middle is the dynamic recording and the bottom the condenser. The big time lag between the first one and second two is recording latency. But since the bottom two share the same latency, we can compare between them.The barely visible time markers up top are milliseconds. The vertical markers are a little bit less than 1/2 a millisecond. Note how the original 500hz signal take 2 milliseconds - about 4 vertical markers - to complete. A 90 degree phase difference will have a comparable tone at the same point in its wave cycle .5 milliseconds later, about exactly one vertical marker.Take a look by the third vertical marker - the dynamic signal is just hitting the axis. While the condenser signal is a little behind, it crosses its axis much closer to that third marker than to the fourth one. While there is a time difference between the mics, it's not attributable to a 90 degree phase difference. It's a mix of small stuff like mic response, construction, position differences. I think this means the theory is wrong. Very curious to hear how others interpret it. (And why DPA would be wrong on this, since they make microphones.)= Justin

I sat with this for about an hour and the one thing I couldn't figure out was what the wave forms would really look like if they were 90 degrees out of phase. Something about how they both represented the sudden start and then stop of excitation of the diaphragm made it not sit right.I ran it again, but this time for a more prolonged tone signal and at a lower frequency:Now this is interesting. In this case it looks like the signals are in fact about 90 degrees out of phase of one another. But there's a chance here that this just happens to be a cumulation of the possible other factors - positioning, signal chain.So I tried one more long signal, this time with a slowly increasing frequency. (Please ignore the crazy frequency response jump on the Stedman, but do admire the relatively flat response of the e22s).So much for disproving the theory. The difference in cycle positioning appears to stay consistent across the mics, despite a varying frequency. So it's not because, say, one is a little closer to the sound source. I agree with the general note above that one should rely on her or his ears to make the final judgment. But this seems to be a point of theoretical consideration, anyway, when trying to decipher what's going on between picking up a single sound source with both a dynamic mic and a condenser mic.I need to give a little more thought on the impact on a sound that's more complex than a sine wave.= Justin