the "0" buttons on plug-ins???

[tommydee]

on most RTAS plugs, there are these two buttons that look like O's with a slash through them...

i have precious little idea what i'm doing with plug-ins... i just play around with 'me till something sounds good...

but i'd love to know what those two buttons are for... and how i'm supposed to use them.

kind regards,

tom.

[coaster]

these buttons reverse the polarity of the incoming signal.

dont use them unless you want to reverse the polarity of the signal.

occasionaly a drum kit will have certain mics that sound better out of phase with the rest, and there is no clear cut rule why it works on some kits and not others.

often times the kick/snare will like to be out of phase with each other, often times not. it depends on the situation.

[tommydee]

thanks for the speedy response...

now here's another ignorant question: what's polarity?

and can you give me another example or when i might want to push those little doo-dads?

t.

[Chompers]

Polarity......

A sound wave goes up and down. Swithching the polarity makes them go down and up.
Exact opposite waves.

[RobbaDobba]

I think tommydee is looking for the layman route on explaining "polarity"...

If you press the "0", it will cause your audio to become what's known as "out of phase". This means that if you play the signal back in mono, there will be a drastic drop across most of the audio spectrum...you won't hear vocals or much else. In stereo, it will have a strange, wider, off-balance sound that will drive you absolutely nuts.

On the other hand, if something is already out of phase (say a production house sends you something that is), by pressing the "0" button, you will put it BACK INTO phase.

If someone can explain it better, go for it. Hope this helps, though.

[hyp0static]

Hitting the "0 with a slash through it" won't necessarily put it out of phase, but it will swap the polarity 180 degrees.

Think about it like this, tommydee. Let's say you double mic a snare - one on top, and one on the bottom. Sound waves are areas of built up air pressure - positive and negative, push and pull. When you hit the snare, you are making the skin on the top of snare go in - kind of like a negative pressure area. At the exact same time, when you press in on the top skin, it is pressing the bottom skin out. Is this making sense? So at the top, you have a negative pressure zone, and at the bottom you have a positive pressure zone. Assuming both of your mics are wired the same (same pin is "hot"), the top mic will be receiving a negative pressure signal while the bottom mic receives a positive pressure signal. Then when the top mic gets a positive pressure signal, the bottom mic gets a negative signal.

The mic signals are out of phase, and quite possibly out of polarity. If you have them panned up the center and both faders at the same level, the snare may sound a bit thin. Since +1 + -1 = 0, if the signals were exactly opposite polarity, you would hear absolutely nothing. Since the signals are a little different, you may experience just a thinning of the sound. If you swap the polarity of the signal of one of tracks, you may hear the sound get meatier, more full. Now the peaks are reinforcing each other instead of cancelling each other out.

Like RobbaDobba was saying - if you have something out of phase (especially one of your speaker cables, for instance) it will sound really funky, like your head is being sucked in. Try it on say a stereo file of a song. Flip the polarity of one of the channels and listen in stereo. You'll probably really notice funkiness in the bass frequencies. When a bass note hits (which "should" be in the center), what should happen is both speakers (left and right) move in together and out together. Switch polarity on one channel, and now when one speaker's cone goes out, the other speaker's cone is going in. . .

The reverse polarity button can also work with a mic'ed bass cab and a DI. Also, like in the previous examples, the polarity of a snare mic might not agree with the polarity of the kick drum (think about the mic position and how the sound/air waves are hitting the mic - not just the kick drum/kick mic but in relation to the how the snare mic is picking up the kick drum sound).

Anyway - hope that helps a bit.

hyp0static

[This message has been edited by hyp0static (edited May 03, 2001).]

[tommydee]

this forum rocks -- thank you all for your help.

(i was pressing them buttons left and right the other night... so i now need to go back to my track and see what's on and what's off.... and what the difference is.)

(it actually sounds good in stereo and mono so i got lucky...)

the whole phase/polarity thing is still kind of confusing.... so i think i'm going to go pick up a book on sound theory.

kind regards,

tom.

[Shawn Parr]

A really good starter book if you don't have it already is the Yamaha Reinforcement Handbook. It covers a lot of terrritory, but isn't terribly difficult to understand. It is really good when you are starting out, and if you are like me it helps to add more gak to the backseat of your car. . .

A much more in depth book that I like is the AudioCyclepedia, but it is also pretty expensive, although well worth the cost.

My two favorite nitty-gritty type of books.