Audio Basics, Episode 1: Signals, Waves, Mixing, and the Physics of Audio
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- Опубліковано 4 жов 2024
- The day has finally arrived where I start my course on audio production.
In this first lesson I'll talk about how sound is generated, how it moves through the air, what an audio signal looks like, how sounds are combined (mixed), and how that relates to balanced vs unbalanced audio.
Grab a snack and a drink, get cozy, because this one is a bit long.
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Hope this gets more views. It's excellent! I learned a ton.
A shame that the video does not rank good. Seams UA-cam mimics the reality. I personally did Trainings on audio (specifically on XLR and its advantages) cause there were problems in using wrong adapters. Spend hours to make it vivid. Nobody listened „that boring lesson“ and it was like before. Adapters were build to adapt XLR to 3,5 and „left“ was recorded hot and „right“ was recorded cold 😂😂😂 sound quality in the school hall after cutting and no additional audio processing was amazingly bad. It was the time were we using macrosystems Casablanca 😎🤪
It’s so cool to watch the beauty of symmetrical signals live on your software. Can we get this peace of art?
Any video that has the phrase “That got more nerdy than I intended.” Is probably a great one. 😂
Watching this to boost your visibility!
Thanks Doug!
This is great. Looking forward to the other videos in this series. Learnt a lot today
Hi, Doug. Unfortunately not always a great video performs well. This is really educational even if people know some about sound.
The software you created is really complete and seems very ready for the purpose. I run a school in Portugal where we teach video and sound, and would be very happy if you could let us use it.
If not, thanks anyway.
I don't have an issue making it available, but it still needs a little bit of polish before I can unleash it to the world.
Great video. At Uni a few years back learning about this sort of stuff, they talked about "balanced audio" but I never understood what it actually meant. When you explained what the pins in an XLR cable do, it made sense immediately.
I don't know about other people but I'm a nerd who sometimes needs to have a full understanding of all the physics and signal processing before I can comprehend what a device is doing, so this was super helpful and I'm looking forward to the next part of the series!
Something I would love to learn is how analog audio becomes digital, as in how does it translate to ones and zeroes and does that have something to do with what a bit rate/sample rate is? I assume its the size of the pieces the analog signal gets chopped into which is then converted to a number, but I'd love to know how that happens and what devices mostly use analog vs digital audio.
I will definitely be covering analog vs digital. I want to make sure that I cover the basic concepts of audio first before I get into that. Sort of a layer on top of the other ground work I'm laying here.
Cool software.
Excellent video. The existence of balanced audio cables does beg the question of why unbalanced audio cables still exist. The bad answer to that is, of course, that unbalanced outputs exist and you can't get balanced audio from an unbalanced output, no matter what cable you're using. But that just moves the question one step further; do unbalanced outputs need to exist in 2024?
Unbalanced work fine for consumer electronics. And for short runs of just a few feet/meters, they're usually not a problem. But it would be a better world if all audio connections were balanced.
@@djp_video Wow, a reply! Thank you! Coming from IT originally, the mentality of not optimizing away unbalanced audio is a bit jarring. That it hasn't happened has always implied some fundamental barrier to me.
Common mode rejection!
@@Andreas-ov2fv The same concept is used in IT as well. Ethernet and USB, for example, use balanced signals for data communication, though that particular term isn't really used in that context. But it is the same.
Great !!!
Very well explained. Thank you!
I love the app you created, Doug
Thank you!
Thank you. Really enjoyed.
And I thought I knew audio, tsk tsk. Thanks Doug.
Thanks a lot !!
Audio snob here as well.
Hello Doug from Greece!
I have an atem constellation 2me hd switcher.
I stream with my Magewell Ultra Stream SDI encoder.
I have a problem, and I hope you to help me figure it out when I stream stereo sources.
When stereo sound passing through the camera (sdi cable) everything is fine.
When stereo sound passing through TRS analog audio jacks sound seems to have phasing effect. Music sounds weird and in microphones canceling everything.
Do you had ever in the past same problem?
From the headphones I hear everything perfect, and the recording as well. Only in livestream
I have problem. I checked in UA-cam platform not other platform.
Because you starting a series of video dealing with audio if you thing is something that is related to, please mention if to a future video.
Dimitris
A fun of you.
PS
Hope it makes sense my problem to you, because I don't know English very well.
But I understand you very well in your videos.
Those are the exact symptoms of having an unbalanced, stereo audio source being plugged into a monaural balanced input. An incompatibility between balanced and unbalanced connections.
As demonstrated in the video, the audio that the switcher "hears" on its input is the *difference* between the signal on tip and ring of the connected cable. If the connected source is stereo (rather than balanced), that device is putting the left audio channel on the tip and the right audio channel on the ring. So at the input, the switcher is getting the left channel where it's expecting the hot (+) side and right channel where it's expecting tthe cold (-) side of a balanced signal.
Since the audio that the switcher hears is the difference between what is on the left vs right channel, you only hear sounds that are either in the left or right channel, but anything in both gets cancelled out and removed. That, and everything that does come through from the right channel has its phase inverted, creating a weird spacious, behind- or above-you rather than distinct in-front-of-you sound.
The fix is to use the right cable. If you have a stereo unbalanced source that you want to connect to balanced audio inputs, you need a cable that splits the signal into two separate wires -- one for the left, and one for the right. So one end of the cable would have a TRS (or mini TRS) for stereo and the other end of the cable would have two TS connectors to split that into left and right. Something like this: amzn.to/45MSQ8M
If you're already using an insert cable and still have the problem, that's a sign that the ground (sleeve) connection is broken and the cable needs to be repaired or replaced.
10:50 - I don't hear "two distinct tones," I only hear one. 🤷♂
It's the combination of the tones heard at 6:35 and 6:38.
@@djp_video I guess this is why I'm in video and not audio. 😂
How is the inverse signal generated that travels down the 3rd XLR pin?
@@daltonrandall4348 It's literally just the inverse voltage... reversing the +-/ sign.
So, if at one moment in time the voltage on the (+) wire is +1.0V, the other (-) wire would be - 1.0V. Or when the signal on the (+) wire is - 0.5V the (-) wire is simultaneously +0.5V. They always mirror each other -- at least at the source anyway before noise is picked up by the cable. (Remember that even the normal/hot/+ signal goes both above and below the baseline, so it's a positive voltage for roughly the same amount of time as it is negative; we just use the + and - or hot and cold designations to indicate which signal is the original and which is inverted.) It really is that simple. Looking at it on the graphs in the video, it's exactly the same signal, just flipped upside down.
@@djp_video Cool, thanks.
I never got a notification. I’m interested in audio.