|
|
Post by christopher on May 23, 2023 23:01:53 GMT -6
Ok,
I’ve been searching the internet and there’s not a lot of info. It’s crazy the amount of arguing with experts over whether it matters.
First thing I’ll get out of the way..
- YES it is AUDIBLE!
- YES it does matter, but I admit only if you really care.
PROOF.. How do I know? One of my favorite go to (possibly broken) limiters was made before computers and it sounds kinda cool. Well when I record with a computer I can look at the waveform and find it’s only limiting the positive side, the negative side is unaffected. Flip polarity to reversed and a kick (or bass or guitar) is more dynamic and jumps around in a mix. Flip the normal way and it sits in a mix perfectly controlled and fine. It’s very easy to hear differences. Actually that is something I discovered by ear before I even noticed the waveform was asymmetric. It’s also sort of a way I can “undo” my over crushed limiting later. Now.. if we extrapolate to all instruments and gear behaving differently at positive and negative moments, there’s tons of room to be audible there. No debate I hope.
Now.. big question.
- What is the preferred way to confirm a studio chain is setup for absolute polarity?
Starting at the mic. Then XLR. Then mic pre etc.
Do I just clap and plug into an interface pre, watch the waveform?
Monitor speakers is another issue. It can be hard for a beginner to hear what an out of phase stereo pair sounds like. And it’s still a brain teaser for me at times. I can make it so they are in phase by ear. How do I confirm absolute polarity so that a positive wave is pushing outward?
Passive speakers: is it ok to use a 9volt?
Active speakers.. any tricks there?
Should I playback a recording of a kick and record that with a mic?
|
|
|
|
Post by yewtreemagic on May 24, 2023 11:16:48 GMT -6
Best evidence for my ears was to download the files kindly provided by Matthias Carstens of RME: www.rme-audio.de/download/polarity_hearing_testfiles.zipThe easiest to hear test is to plug your Headphones into your headphone socket and listen to the 20 Hz Sawtooth.wav contained in this zip file - by default, with polarity on my Lavry DA10 converters set to 'normal' the L/R signals were 'pulling' at your ears, but with polarity set to 'invert' both the signals 'push' at your ears, and this correct 'absolute' setting (an outward-going woofer for most impact) became obvious. I then went on to test my loudspeakers with the same signal and could hear the 'push' version nearly as easily (as it happens, the best polarity setting for its headphone output also turned out to be the best for my loudspeakers, which was handy), and then checked the rest of my signal chain further back (audio interface, mic preamps etc.) Then (unless I've forgotten something) you'll only have to check your mics themselves, where a kick drum could indeed be a good test signal. N.B. Personally I wouldn't test passive loudspeakers with a 9-volt battery, but consider the power amp and loudspeakers as a single unit checked with the 20Hz sawtooth test signal. Martin |
|
|
|
Post by christopher on May 25, 2023 11:28:43 GMT -6
Thank you Martin,
I downloaded and listened. I heard a difference, though it was a little tough. Inverted my headphones seemed slightly deeper, normal seemed more point. It seemed like my headphone out chain are also inverted. So I came up with a strategy to help confirm:
I loopback an unbalanced 1/4” guitar cable from heaphone out to interface trs input. The ring will short and Tip will record. Then back the cable out halfway so tip is touching the female ring (input TRS side). That will appear inverted.
So far recording a loop back of 20Hz saw has shown me Tip(+) inverted, and ring (-) is normal. So yeah it looks like my headphones output jack is inverted. I did do custom wiring so I could have messed up something there, but I normally trust myself not to screw that up.
Bob Ohlson did post about how a polarity switch for headphones is extremely helpful for ‘more me’ when using a mic. That makes so much sense when I read that. So I wonder if manufacturers just pin out inverted on purpose?
My next test:
Use an XLR that I confirm continuity with a multimeter for correct hot/cold to record some mics into the same input. They should all look the same and tell me how the input is wired
|
|
|
|
Post by winetree on May 25, 2023 14:14:04 GMT -6
|
|
ericn
Temp
Balance Engineer
Posts: 14,921 
|
Post by ericn on May 25, 2023 14:38:41 GMT -6
m The cricket is awesome and I remember using the Turbosound version that cost $400 in the 80’s. |
|
|
|
Post by jeremygillespie on May 25, 2023 16:01:10 GMT -6
On installs…
- every cable gets checked. Beep em all out make sure pin 2 hot etc etc. Same with all cables connecting gear etc.
-To check outboard, patch signal generator into a mult. Then one goes to a fader on the console, throw that fader at 0, other goes into your gear, out of the gear, and onto another fader. Slowly bring the gear fader up. If the signal goes away, your outboard is out of phase, if it’s good, signal will get louder.
- use a clicker to test mic signals. Lots of older ribbons were pin 3 hot. If you don’t want to open the mic make a 6” long flip cable and label it with shrink wrap.
- if I’m at a studio that isn’t my home base, I schedule an hour before anybody shows up so I can beep cables and do the outboard trick. Makes life easier in the long run to not be worrying if that compressor or eq is wired all wrong. I have some tt patch flip cables I bring with me just in case the patch bay at said studio doesn’t have flips on the patchbay (they should).
- I have run into a particular Neve broadcast console that was wired pin 3 hot. Not much you can do there haha.
- an old 9v battery touching leads on the speaker can show you if the last person that replaced a woofer in those crusty old ns10’s that have been on the meter bridge for 30 years did the job correctly.
- record one tick of a click track and play it back gently holding your hand against the edge of a speaker woofer will tell you if the speaker is pushing or pulling. Sometimes it can be hard to tell so if you get one wav of a 100hz size wav it can be useful.
That’s all I got
|
|
ericn
Temp
Balance Engineer
Posts: 14,921
|
Post by ericn on May 25, 2023 16:24:27 GMT -6
I haven’t used it but AudioTools iPhone app has a phase checker.
|
|
|
|
Post by christopher on May 25, 2023 19:29:48 GMT -6
just a quick update: I went through a few mics and did my best beatbox version of a low passed Kick… directly toward the capsule. They all showed positive as the first spike. So my interface input is performing as expected. That will be my control.
Figure 8 on mics showed positive for front, back side showed negative. Except for the cheap Stage Right ribbons, Fig8 is polarity reversed like a vintage ribbon (thanks Jeremy!)- - unless the logo side is the back? Which I now think it is. The Serrano 87 stayed positive in Omni and high pass modes. That was reassuring
|
|
|
|
Post by nudwig on May 26, 2023 17:17:44 GMT -6
|
|
klaus
New Member
Posts: 9
|
Post by klaus on May 28, 2023 17:37:11 GMT -6
I
|
|
|
|
Post by chessparov on May 30, 2023 9:26:45 GMT -6
Fortune Cookie say... "Man who makes Phase Checker for Teenagers shall be made King of Inventors"  Chris |
|
|
|
Post by EmRR on Jun 6, 2023 18:23:09 GMT -6
OK....live remote, dueling jazz singers with their handheld mics and cables, kept fighting one for intelligibility in post, sure enough flip polarity and it's there.
|
|
|
|
Post by Ward on Jun 7, 2023 7:54:57 GMT -6
OK....live remote, dueling jazz singers with their handheld mics and cables, kept fighting one for intelligibility in post, sure enough flip polarity and it's there. Fascinating. Does this mean putting one singer out of phase with the other? |
|
|
|
Post by EmRR on Jun 7, 2023 8:04:36 GMT -6
Don’t think so, it’s the mic or the cable. Neither mine.
|
|
|
|
Post by drbill on Jun 7, 2023 8:55:25 GMT -6
I've shared this before. Back in the day, I had one engineer who checked absolute phase (polarity) from beginning of signal to end every single time he came in the studio. First thing he would do when getting in was to flip the NS10's on their backs. Took a kick drum thru the console, and played it fairly loud thru the speakers. Put a nickel on the woofer. Played kick drum. Flipped polarity on console, did it again. The positive (correct phase) position would launch the nickel up in the air. The negative (out of correct phase) would just push the nickel off the center of the cone.
He did this EVERY time he came in the studio. Even if he'd only been there a couple of days earlier. And even though I had done all my wiring right, and nothing had changed. LOL. It's a lot easier nowadays with DAW's, and still just as important. Nowadays, I've got wiring polarity checkers to do the job.
|
|
|
|
Post by paulcheeba on Jun 7, 2023 16:52:41 GMT -6
I understand polarity is completely different to phase but I’ve been using Auto Align 2 this week on drums where the phase was already as accurate as was physically possible for the amount of mics I was using and Wow the drums leapt out the speakers and really started moving. I recommend it by Sound Radix. The best tool I have heard in a while.
|
|
|
|
Post by wiz on Jun 7, 2023 17:14:56 GMT -6
I've shared this before. Back in the day, I had one engineer who checked absolute phase (polarity) from beginning of signal to end every single time he came in the studio. First thing he would do when getting in was to flip the NS10's on their backs. Took a kick drum thru the console, and played it fairly loud thru the speakers. Put a nickel on the woofer. Played kick drum. Flipped polarity on console, did it again. The positive (correct phase) position would launch the nickel up in the air. The negative (out of correct phase) would just push the nickel off the center of the cone. He did this EVERY time he came in the studio. Even if he'd only been there a couple of days earlier. And even though I had done all my wiring right, and nothing had changed. LOL. It's a lot easier nowadays with DAW's, and still just as important. Nowadays, I've got wiring polarity checkers to do the job. I would FREAK OUT if someone moved my monitors....I would flip them on their back, put a nickel on them and kick em and see if THEY were in correct polarity... 8) Man it took me a lot of time to position my monitors... cheers Wiz |
|
|
|
Post by wiz on Jun 7, 2023 17:16:39 GMT -6
I understand polarity is completely different to phase but I’ve been using Auto Align 2 this week on drums where the phase was already as accurate as was physically possible for the amount of mics I was using and Wow the drums leapt out the speakers and really started moving. I recommend it by Sound Radix. The best tool I have heard in a while. When I was doing live drums here... their Leveller plug in was a god send... ps.. I no longer do live drums, and will sell my copy of leveller cheap to anyone who wants it... By the way.. I only just learned that you did the song "Rome wasn't built in a day" its one of my favourite tunes from back then... really great song and production... if you feel so inclined could you tell a little about the recording and mixing of the tune? cheers Wiz |
|
|
|
Post by drbill on Jun 7, 2023 18:15:09 GMT -6
I've shared this before. Back in the day, I had one engineer who checked absolute phase (polarity) from beginning of signal to end every single time he came in the studio. First thing he would do when getting in was to flip the NS10's on their backs. Took a kick drum thru the console, and played it fairly loud thru the speakers. Put a nickel on the woofer. Played kick drum. Flipped polarity on console, did it again. The positive (correct phase) position would launch the nickel up in the air. The negative (out of correct phase) would just push the nickel off the center of the cone. He did this EVERY time he came in the studio. Even if he'd only been there a couple of days earlier. And even though I had done all my wiring right, and nothing had changed. LOL. It's a lot easier nowadays with DAW's, and still just as important. Nowadays, I've got wiring polarity checkers to do the job. I would FREAK OUT if someone moved my monitors....I would flip them on their back, put a nickel on them and kick em and see if THEY were in correct polarity... 8) Man it took me a lot of time to position my monitors... cheers Wiz I had tape on the meter bridge so you could see exactly how they were positioned. No biggie. If someone is paying your rate, they can do what they want - within reason. |
|
|
|
Post by christophert on Jun 8, 2023 5:58:30 GMT -6
I understand polarity is completely different to phase but I’ve been using Auto Align 2 this week on drums where the phase was already as accurate as was physically possible for the amount of mics I was using and Wow the drums leapt out the speakers and really started moving. I recommend it by Sound Radix. The best tool I have heard in a while. Hey Paul, I just upgraded this a few weeks ago, no chance to use it yet. I used the first version a while ago and it was never great.
Are you lining up all of your individual drum mics up to your overheads - or everything to the kick and snare? I'm wondering what approach to take with at least 12 drum mics.
|
|
ericn
Temp
Balance Engineer
Posts: 14,921
|
Post by ericn on Jun 8, 2023 9:22:08 GMT -6
I understand polarity is completely different to phase but I’ve been using Auto Align 2 this week on drums where the phase was already as accurate as was physically possible for the amount of mics I was using and Wow the drums leapt out the speakers and really started moving. I recommend it by Sound Radix. The best tool I have heard in a while. Hey Paul, I just upgraded this a few weeks ago, no chance to use it yet. I used the first version a while ago and it was never great.
Are you lining up all of your individual drum mics up to your overheads - or everything to the kick and snare? I'm wondering what approach to take with at least 12 drum mics.
If I were one of our resident gear Manufacturers I would build a 500 series with variable High and Low Pass filters and Phase alignment filters. Imagine you’re Sitting behind Benny’s new FiX dialing in the drums during tracking and you reach up and dial in the high pass then phase align the drums. Talk about house cleaning your tracks! |
|
Chris
