Avalon 737 Phase Invert

J

jamest748

New member
Hey,

New on here so hi! Just a quick question, my signal path is Neumann U87ai - Avalon vt737 - EMU 0404 - Sonar 8.5 Producer.

When I record my acoustic guitar with the Neumann up close and select Phase Invert on the Avalon the sound is much better. It's more present, maybe a bit louder but clearer almost. Is this normal? Or am I doing something wrong?

Thanks in advance!
James.
 
Yo James! Welcome to the board! That would depend on where you are standing. Sound consists of real physical moving (hopefully) waves. Picture the sine wave- form it goes up and down. If two more or less identical wave forms meet so that one is going up exactly when the other is going down, they tend to cancel each other out (phase cancellation). If they meet from opposite directions, like a head on collision, they can create the dreaded "standing" wave. A sound in one place that doesn't move, which is really freaky. Most likely, where you are playing, the sound from your guitar is bouncing off one or more hard surfaces, coming back, and meeting up with a more or less identical wave, either causing partial phase cancellation or phase distortion, which often occurs when two identical waves arrive at *almost* the same time. Most likely, reversing the phase on the signal is preventing that, which is basically what it's for. If you do this at a different location or in a different room, it won't be the same. You have to use your ears every time. BTW, you have a very nice signal chain. Folks here will be jealous.-Richie
 
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:D
Ah, cheer guys, that makes sense to me!

Thanks, I've finally got round to upgrading some of the equipment and decided to go all out!

Might be a bit excessive for a home studio but I'm a bit of a perfectionist and wanted the best sound I could get. Just waiting on an AD/DA converter.

I understand what you're saying and that does make sense. As I'm recording and playing solo I have to test the levels and mic settings in front of the Avalon but when I'm recording I have a home made isolation booth so I think the sound would be different behind that. Maybe it's worth getting someone round to play from where it will be actually recording from then I'll be able to set up the Avalon perfectly for that environment.

Cheers, I'm going to keep looking on here there's loads to learn! :confused:
 
Richard Monroe said:
Yo James! Welcome to the board! That would depend on where you are standing. Sound consists of real physical moving (hopefully) waves. Picture the sine wave- form it goes up and down. If two more or less identical wave forms meet so that one is going up exactly when the other is going down, they tend to cancel each other out (phase cancellation). If they meet from opposite directions, like a head on collision, they can create the dreaded "standing" wave. A sound in one place that doesn't move, which is really freaky. Most likely, where you are playing, the sound from your guitar is bouncing off one or more hard surfaces, coming back, and meeting up with a more or less identical wave, either causing partial phase cancellation or phase distortion, which often occurs when two identical waves arrive at *almost* the same time. Most likely, reversing the phase on the signal is preventing that, which is basically what it's for. If you do this at a different location or in a different room, it won't be the same. You have to use your ears every time. BTW, you have a very nice signal chain. Folks here will be jealous.-Richie
Click to expand...

But the OP is talking about recording with one mic... even if there were these kind of phase cancellation issues from the room, flipping the polarity of the signal would do nothing... the issues would still exist because the whole signal would be inverted.

Is this a difference you've tested and can discern upon playback, or are you talking about it sounding better when monitoring yourself playing live? Maybe its something to do with your monitoring chain... are you listening through headphones whilst playing? Playing with open monitors?

Theoretically it should make no audible difference to the signal by itself, certainly not making it clearer and louder. Some people claim to be able to detect the difference with highly transient signals that are highly asymmetric across the zero-line, e.g. a sharp kick drum, where I can see it may be possible to 'feel' the difference due to the different direction of the excursion of the speaker cone for the initial attack because one would expect the speaker cone to push outwards, not pull inwards. We're talking transverse pressure waves here though, and so my physics instinct tells me to remain sceptical :p
 
I agree. You're right, Matt. I was thinking of phasing reinforcement of a feedback loop, which is why they put phase reversal switches on acoustic guitar pickups. However, that doesn't apply in a single mic recording situation, even in figure of 8, as the diaphragms are so close together. No speaker, no feedback loop. Reversing the phase should do nothing, My bad.-Richie
 
This leaves a question as to why the phase invert gives an apparent higher level to signal according to what matt said that switch wouldnt have any affect. However it does......
 
For a single mic, the phase switch should produce no discernable difference.

Sounds like the Avalon phase does something more than just flip phase.

For grins, I'd record it both ways, then flip phase in Sonar itself.
 
Hi, sorry just read your messages.

I'm clicking in the 'Rev' button which I think is the Phase button!

I'm monitoring through headphones so not sure what difference that makes. I'll try recording with phase and without phase and post the results up on here. Again, with only one mic it seems odd that with phase enabled it sounds better! Maybe it's just my ears! How do I post audio tracks on here? Do I have to host them somewhere else and post a link?
 
Record the two clips as closely similar as possible, then save them as 320kbps MP3s and dump them on http://lightningmp3.com/

Am I the only person being bothered by Avalon's misuse of terminology, e.g. "phase reversal"? Its polarity inversion, goddammit!
 
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