Out of phase sound problem

mark-y wrote on 7/1/2023, 12:58 PM

You can invert or shift the phase of one stereo channel in almost any version of Sound Forge. Don't line the peaks up exactly though, "some" phase shift is what gives the sound its sense of stereo separation.

Some condensor mics are wired 180 degrees, I've seen it before. If you want to upload a sample file to Drive, I can take a look at it.

DMT3 wrote on 7/1/2023, 1:23 PM

Use only one channel of the mic. You can also adjust the phase in Vegas.

xberk wrote on 7/1/2023, 2:04 PM

Use only one channel of the mic. You can also adjust the phase in Vegas.

@DMT3 .. Thanks!! I ran a test and your solution seems to work. I converted all the audio to "left channel" in Vegas, then rendered that. It comes out as stereo with two channels but when played back as "monaural" or "stereo" everything seems ok. BUT ---

Do I need to worry about this since my ONLY distribution is on YouTube? How would someone choose to playback YouTube in Monaural?

@mark-y .. I'll try to upload a sample for you later today.

DMT3 wrote on 7/1/2023, 2:05 PM

It should be fine. If the audio is identical on both channels, there is no phasing problem. And you can temporarily set Vegas to Mono output and listen for problems.

john_dennis wrote on 7/1/2023, 4:17 PM

Like a good student, I'll show my work.

This is the result of inverting one channel in Sound Forge.

This is my analysis of the downloaded youtube file.

I wouldn't normally work on final files, but it's 99 degrees outside headed to 101 degrees and I'm not going out there.

set wrote on 7/1/2023, 4:33 PM

Mod note: Just edit the original message to add links for easier navigation in both threads. Hope this helps readers. Thanks for sharing.

Question: is this 'invert phase' similar function?

xberk wrote on 7/1/2023, 4:53 PM

@john_dennis .. Thanks. I can hear a big difference but I don't detect that difference when playing back the posted YouTube video on YouTube itself. I never knew about phasing. Still murky to me.

Using that Mic with my new Sony A7iv is what caused it.

I changed the audio in Vegas to Left Channel only. Then rendered the same short segment. How's that?

john_dennis wrote on 7/1/2023, 4:57 PM

@set said: "Question: is this 'invert phase' similar function?"

It doesn't sound like it to me.

john_dennis wrote on 7/1/2023, 5:00 PM

@xberk said: "I changed the audio in Vegas to Left Channel only. Then rendered the same short segment. How's that?"

Sounds dulcet to me.

xberk wrote on 7/1/2023, 5:16 PM

@xberk said: "I changed the audio in Vegas to Left Channel only. Then rendered the same short segment. How's that?"

Sounds dulcet to me.

So that seems to be the "easy fix" once you are in this predicament .. edit as normal and at the very end compile everything with one audio channel and render from that.

I don't expect my stuff to get downloaded at YouTube but merely played back. So can anyone tell me how you playback at YouTube in Monaural?

mark-y wrote on 7/1/2023, 7:40 PM

I downloaded your YT file and it's clear what is happening. Without getting too technical, the adaptor you are using is referencing both sides of the balanced output to center, causing the phase cancellation you discovered. You can see that the uppies line up with the downies 🙃🙁

They should be referenced to each other to create a full power unbalanced signal for your camera. Here I flipped the left channel. Sending one signal to both sides does the same thing (your solution).

Here is how they look and sound:

Out of Phase (your original)
Correct Phase (one channel flipped)
"Stereo" Simulation (small phase shift added)

For the stereo simulation, I used a Simple Delay preset in Sound Forge. There are better ones. @xberk @john_dennis

xberk wrote on 7/1/2023, 8:19 PM

I downloaded your YT file and it's clear what is happening. Without getting too technical, the adaptor you are using is referencing both sides of the balanced output to center, causing the phase cancellation you discovered. You can see that the uppies line up with the downies 🙃🙁

They should be referenced to each other to create a full power unbalanced signal for your camera. Here I flipped the left channel. Sending one signal to both sides does the same thing (your solution).

Here is how they look and sound:

Out of Phase (your original)

Correct Phase (one channel flipped)

"Stereo" Simulation (small phase shift added)

For the stereo simulation, I used a Simple Delay preset in Sound Forge. There are better ones. @xberk @john_dennis

@mark-y .. Thanks! I think I prefer the zero degree phase. Sounds good to me.

Sound is important. I'm glad for the help and discussion here on this problem. I'll be looking for a new mic that I can mount on a little boom stand.

mark-y wrote on 7/1/2023, 9:08 PM

Heh I'm using a mic almost identical to yours for Zoom and Youtube as well as narration in Vegas. It is an Audio-Technica Pro45 hanging directly over my head.

I use just a little compression and low-mid enhancement to disguise my nasal voice.

I looked up the specs on your mic and honestly, I think a new DI/Phantom adaptor may be all you need. The quality of your "fixed" audio is quite easy to take.

john_dennis wrote on 7/1/2023, 9:23 PM

"So can anyone tell me how you playback at YouTube in Monaural?"

It's not necessary or desirable to upload a monaural video.

At the clip level, just right click the audio and select left or right channel to apply to both stereo output channels. Copy / paste audio event attributes to all other camera audio files. Background audio can be stereo.

Your phase problem with your mic may be fixed with a soldering iron if you're handy. Your mic sounds fine.

xberk wrote on 7/1/2023, 10:04 PM

@mark-y ... Here's the adapter I'm using now .. Got a recommendation?

https://www.amazon.com/gp/product/B08H24SBMS/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

mark-y wrote on 7/1/2023, 10:18 PM

The phantom supply looks fine. How are you going from the xlr balanced output to the 3.5mm plug to your camcorder? I think that might be where the problem lies.

xberk wrote on 7/1/2023, 11:28 PM

The phantom supply looks fine. How are you going from the xlr balanced output to the 3.5mm plug to your camcorder? I think that might be where the problem lies.

@mark-y

From the Phantom adapter I'm using a XLR to 3.5mm cable.

The A7iv is set to record CH1/CH2. Would I do better using CH1/CH1 ?

john_dennis wrote on 7/2/2023, 12:49 AM

@xberk

OR

will solve the phase cancellation problem going forward. This proves there's a software solution to every hardware problem. It should work fine until you forget the configuration and plug in a stereo mic.

@mark-y

xberk wrote on 7/2/2023, 10:40 AM

Thanks @john_dennis

I suppose the Sony XLR adaptor for the A7iv camera would solve it too -- but that's $600.

https://www.amazon.com/Digital-XLR-Adaptor-Kit-Microphone/dp/B07VCGDP43/ref=cm_cr_arp_d_product_top?ie=UTF8

mark-y wrote on 7/2/2023, 11:14 AM

Yeah a cable won't flip the phase for you. In lieu of a Direct Box, John's solution will work fine as long as you get enough audio gain without any hiss. Or, you can continue to invert the phase of one stereo channel in editing, same result. Your SNR is actually pretty good, around -48dB on each side.

xberk wrote on 7/2/2023, 11:23 AM

@john_dennis

@mark-y . Thanks for your help Mark and John .. much appreciated.

john_dennis wrote on 7/2/2023, 11:37 AM

By far, the cheapest hardware solution would be to open the Canon connector, move the right channel wire on the XLR end to the left channel pin. The left channel would then drive both 3.5 mm inputs. There might be an impedance defugality, but it'll still sound real good from my house.

xberk wrote on 7/2/2023, 12:23 PM

@john_dennis

I do use other mics. So it would be best to not have to change settings inside the A7 camera.

Wouldn't this work?

https://www.amazon.com/Hosa-GXX-195-XLR3F-XLR3M-Reverser/dp/B000068O4L/ref=sr_1_4?crid=2TXSW10GKCD5K&keywords=xlr+phase+reverse&qid=1688318561&s=musical-instruments&sprefix=xlr+phase+rever%2Cmi%2C132&sr=1-4

mark-y wrote on 7/2/2023, 12:46 PM

No I don't believe that would work. It looks like it reverses the phase of the balanced legs, not just one side.

I'll do some research, and get back to you on the small Direct Boxes (DI) now available. There may be one that outputs unbalanced L/R from a single balanced XLR input.

Direct boxes are called "DI" boxes, which stands for "Direct Injection". In your case, their purpose is to convert balanced or low-impedance microphone signals into a signal suitable for direct connection to the unbalanced stereo inputs of your camcorder.

In addition to doubling the signal voltage available to each preamp input (minimizes hiss), most have the advantage of an optional Ground Lift, which greatly reduces hum in noisy electromagnetic environments, such as where there is fluourescent lighting.

The chief disadvantage of using a Direct Box is that it's another piece of equipment in the line between mic and camcorder. They are especially needed in field shooting conditions, where wireless microphones and noisy ambient conditions are in play.