Understanding Waveform and Loudness

[DVDdoug]

That is all good to know, but can someone please answer my questions in my last post at: Mon Nov 23, 2020 12:53 pm

I think we're in different time zones. But if you're asking about perceived loudness I commented on that a few posts up...

[InternetStream]

this one sounds a bit distorted

That's because it is distorted. The track has peak clipping or limiting. See at 19.7 seconds, all the wave tips are exactly the same height?

Hey, I recorded that sample 10 years ago and was still new to the concept of "clipping".

My point is that why is the wave form so much higher in the "Off the Record" sample (i.e. 85%) compared to the sample I recorded last (i.e. 25%) and yet the seem to have the same "loudness" when I listen to them with my headphones?


To further prove this point, here are 4 screenshots showing the sample I recorded last night...

1st screenshot shows the original wave form

2nd screenshot is me choosing "Amplify"

3rd screenshot is me listening to it after it is amped up - notice the yellow and red

4th screenshot is me listening to it after it is amped up - with another screenshot showing it going red


Questions:
1.) Why is the waveform at 25% yet the "loudness" at volume = 50% is a tad loud? (Anything I recorded on my old MBP at 25% waveform would be very hard to hear...)

2.) If I used Amplify, be default it should NOT clip, so whyis the amped version going into orange and red?

3.) Why is the amped up version so incredibly loud when I listen to it? (I had to adjust my volume to 25% so it is pleasant to listen to.)

It's very frustrating not being able to refer to a Post # like on nearly every other bulletin board.

This post above got skipped...

[kozikowski]

Sorry. It's not that unusual to get posts scrambled.

not being able to refer to a Post #

No, but each post has a Unique Identifier.

Screen Shot 2020-11-23 at 15.53.16.png (21.52 KiB) Viewed 227 times

See that document icon just to the left of 'by DVDdoug'?

Copy/Paste that into a message.

==========

I don't know why your system is doing that. I expect the behavior of the sound meter, timeline waveforms, and perceived loudness to be the same across ages, versions, and machines.

Whenever I encounter oddities like this, I start looking further afield. Do you use Skype, Zoom, or other chat or conferencing programs? They can leave sound processing behind.

There may be a machine difference. My big 15" Macbook Pro's built-in sound is pretty awful compared to my tiny, delicate 13" Air. The MBPs use little speakers behind the left and right grills. The Air uses beefy compression drivers behind the keyboard. I suspect this is an offshoot of cellphone technology. Night and Day. No trouble enjoying a movie on the Air with good sound.

If I shifted one sound file between the Air and one of the MBPs, there would be a significant sound and volume difference.

I can't account for the waveforms and sound meter apparently not matching. We can wait for a senior forum elf.

Koz

[InternetStream]

Koz,

Sorry. It's not that unusual to get posts scrambled.

Okay.

not being able to refer to a Post #

No, but each post has a Unique Identifier.

See that document icon just to the left of 'by DVDdoug'?

Copy/Paste that into a message.

Okay.

I don't know why your system is doing that. I expect the behavior of the sound meter, timeline waveforms, and perceived loudness to be the same across ages, versions, and machines.

I always seem to get these "I've never seen that before..." scenarios?!

Technically it doesn't affect the quality of things, but it just throws me off since my eyes and brain associate certain amplitude blue wave forms with certain levels of loudness and more so certain editing that needs to be applied.

(I can look at wave forms on my old MBP, and with surprising accuracy say, "Oh, I need to amp this up 1.7..." Just hate to lose that.)

Also, I guess, the smaller peaks make it harder to see things without zooming in which will be a pain.

Whenever I encounter oddities like this, I start looking further afield. Do you use Skype, Zoom, or other chat or conferencing programs? They can leave sound processing behind.

rMBP2 has macOS Sierra and Loopback 2 and Audacity 2.2.2. I also use Zoiper for my phone/VoIP but that shouldn't mess with the system sound.

There may be a machine difference. My big 15" Macbook Pro's built-in sound is pretty awful compared to my tiny, delicate 13" Air. The MBPs use little speakers behind the left and right grills. The Air uses beefy compression drivers behind the keyboard. I suspect this is an offshoot of cellphone technology. Night and Day. No trouble enjoying a movie on the Air with good sound.

Well, I have owned two Retina MBPs for like 4 years now and *never* got the audio working properly, so I did all of my Internet radio show listening on my 11 year old MBP until recently when it has gotten so old I cannot update anything and so I am now having WiFi issues and website issues which is why I desparately need to get all of this figured out!!

If I shifted one sound file between the Air and one of the MBPs, there would be a significant sound and volume difference.

Interesting.

I can't account for the waveforms and sound meter apparently not matching. We can wait for a senior forum elf.

It would be good to know why things have changed.

One good thing is after messinga round all day, I *think* that I have Loopback and Audacity set up so I can not only record my radio shows in Firefox and Chrome, but in VLC and iTunes, and it also appears that I am able to make phone calls using Zoiper and recrod my voice in Track #1, a 15-second beep in Track #2, and the other person in Track #3 so now I have the ability to legally record phone calls should I have a business dispute, and I can also do interviews for a startup that I am working on.

Of course, time will tell how all of that works.

I like Loopback, but combined with Audacity, my browsers, my audio players, and Zoiper, it is still A LOT of settinsg to remember and have to tweak depending on what I am doing which I'm not so happy about.

Sure wish I had one application where I could set up all of my apps and use=cases and not have to do things like tweak audio levels, turn certain apps on and off, etc for a particular use-case.

But I think I'm making some progress.

Sure hope that I can learn more about sound engineering from all fo yous o I can get into producing things like podcasts, radio shows, YouTube videos, eBooks, etc.

[kozikowski]

I always seem to get these "I've never seen that before..." scenarios?!

Maybe, but there's a difference. You don't seem to be trying to do anything weird. You're just doing regular production tasks. The fun posts are from people who start out, "I run my MacBook Pro underwater and the last time it crashed, Audacity didn't recover the show."

I think I hear my mum calling.

Koz

[steve]

it just throws me off since my eyes and brain associate certain amplitude blue wave forms with certain levels of loudness and more so certain editing that needs to be applied.

Try looking at the pale blue region inside the waveform. That's the "RMS level" and it is a better guide to loudness than the peak level.
https://manual.audacityteam.org/man/aud ... tml#colors

[InternetStream]

it just throws me off since my eyes and brain associate certain amplitude blue wave forms with certain levels of loudness and more so certain editing that needs to be applied.

Try looking at the pale blue region inside the waveform. That's the "RMS level" and it is a better guide to loudness than the peak level.
https://manual.audacityteam.org/man/aud ... tml#colors

So where, ideally, do you want the pale blue (RMS) wave forms to be at when you record? And where should they be on a produced piece?

In years past, I just amped things up so the dark blue was at about 85% on the -1.0 to 1.0 scale. That is just what my gut - and my ears - told me. (I did have issues in the early years of not checking things after amping things up and having clipping issues, but live and learn.)


So just like my otehr thread, here is another confusing thing...

While spot-checking my two simultaneous recordings last night, I came across the song by Def Lappard, "Rocket" which has a solid drum beat.

Here are the conflicting results in my two idental rMBP1 and rMBP2...

rMBP1:

rMBP1_Def Leppard-Rocket.jpg (186.73 KiB) Viewed 207 times

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rMBP2:

rMBP2_Def Leppard-Rocket.jpg (219.33 KiB) Viewed 207 times

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Notice how rMBP2 is peaking on the same song, at basically the same place on the waveform.

Why is that?

Identical laptops, idental OS, idental Audacity and VLC and settings.

The only difference is that rMBP2 has Loopback v2.0 and that is the one I reconfigrued last night and got working as far as recording phone calls and recroding my Internet shows in all scenarios (e.g. browsers, players, etc)

rMBP1 does have Loopback 1.2 and it doesn't record phone calls properly. (Will make it identical to rMBP2 after I confirm that rMBP2 is working as well as or better than my old MBP...)

Observations/Questions:
1.) On rMBP2, why is the wave form recording at 0.5 on peaks, yet it is often red-lining on the sound meter?

2.) On rMBP2, why is the wave form recording at 0.5 on peaks, and when volume = 5 it is a little too loud for my tastes on my headphones?

3.) On rMBP1, why is the wave form recording at 0.25 on peaks - for the same Internet radio stream - and yet the sound meter is ranging from -18 to -12dB?

4.) On rMBP2, why is the wave form recording at 0.25 on peaks, and when volume = 5 it sounds about right for my tastes on my headphones?

(Again, on all of my years of recroding on my old MBP, I amped things up to 85-90% and they sounded okay when volume = 5.)

[kozikowski]

rMBP1 looks absolutely, totally, dead normal.

rMBP2 looks possessed by evil spirits.

rMBP2 is also recording from something magic. The information band claims you're recording three sound channels, not stereo (2) and you're recording from whatever "AudacityHub is."

Recording "fold back" (internet) sound is not natural for Macs. It's easy to get multiple pathways, feedback, and distortion. We also note that recording phone calls is difficult or impossible for most people, which is why it got my attention when you said you could do it.

I still think you're a Celebrity Unicorn, but now for different reasons. I think you found a subset of machines and conditions that can do your jobs and you may never find the sames ones again. This pops up occasionally on the forum. There is a podcaster who regularly turns out a Skype conference show between him and his brother across the country with perfect stability and voice quality. Nobody else can do that—even with the same settings and software. He's looking at us all like we're nuts.

No. We're not unicorns.

Koz

[kozikowski]

There is one other note. On the new machine, next time you talk to someone in the system, ask them if they're hearing their own voice coming back to them as an echo. That can be pretty annoying and that's one of the evil side issues of trying to hand-manage sound pathways around a voip call.

Koz

[InternetStream]

rMBP1 looks absolutely, totally, dead normal.

It's "normal" for things to record at 25% yet when played sound normal when the volume = 5?

(I thought when the wave forms were at 50% (i.e. -6 dB) that things would sound normal when the volume in set in the middle at "5"?)

rMBP2 looks possessed by evil spirits.

So help me unpossess it?!

rMBP2 is also recording from something magic. The information band claims you're recording three sound channels, not stereo (2) and you're recording from whatever "AudacityHub is."

That is to be expected...

"AudacityHub" is a virtual device that I created in Loopback which is a "hub" that I plug in my "v_Browsers", "v_Players" and "v_VoIP Call" virtual machines.

So when I am not recording a call, channel 3 is blank because Internet radio stations are "stereo"...

Recording "fold back" (internet) sound is not natural for Macs.

But Rogue Amoeba has made it possible with Soundflower - and now Loopback - since like 2010...

Old technology that works.

It's easy to get multiple pathways, feedback, and distortion.

I'm no sound engineer, but I switched to Macs in 2008 and have been recroding Internet radio shows every weekend since then and I have had no issues recording .mp3's that sound comparable to what I hear on the Internet - which of course isn't necessarily "CD quality" or "analog quality", but still good enough to enjoy.

We also note that recording phone calls is difficult or impossible for most people, which is why it got my attention when you said you could do it.

It is easy using virtual devices in Loopback.

What is difficult is that I am using a very outdated and free version of Zoiper for my "soft phone" and it doesn't offer much as far as sound engineering goes. For instance, it has taken me 6 months to finally figure out last night how to get my voice (Channel/Track 1) and my beep (Channel/Track 2) and the caller's vocie (Channel/Track 3) to all work. More specifically, I couldn't figure out how to get my voice and the beep to both serve as "input" in Zoiper yet come out as separate tracks in Audacity, but I supposedly figured it out yesterday?!

I still think you're a Celebrity Unicorn, but now for different reasons.

What do you mean by that?

I think you found a subset of machines and conditions that can do your jobs and you may never find the sames ones again. This pops up occasionally on the forum. There is a podcaster who regularly turns out a Skype conference show between him and his brother across the country with perfect stability and voice quality. Nobody else can do that—even with the same settings and software. He's looking at us all like we're nuts.

We used Skype on WIndows 7/8 at work before I lost my job back in February, and I spent all day on Skype calls with people across the U.S., and it always sounded like we were sitting next to each other.

Why is that such a big deal?

No. We're not unicorns.

Sorry, I'm not getting what you're calling me...


Tomorrow, I am going to first take screenshots of all of my applications and settings and write a mini "config guide".

Then I am going to upgrade my broken/confused rMBP1 to Loopback 2.0 and set it up like rMBP2.

Now you make it sound like rMBP1 is the "normal" one and that rMBP2 is the "possessed" one, but I cannot make phone calls on rMBP1 because I get weird feedback issues. And I also cannot record phone calls on rMBP1.

It seems like both rMBP1 and rMBP2 did okay recording nearly 12 hours of streaming Internet radio last night. But I dislike how the wave forms do not match the sound meter on rMBP2, and I'm a little confused why both rMBP1 and rMBP2 record such low waveforms yet the recordings seem so much lounder than you'd expect.

Neither of these newer computers matches the behavior I have grown to expect on my 2009 MBP.... *sigh*

Finally, not sure that I have time before I leave on Dec 3, but I ultimately need to install Mojave on rMBP2 because I need a newer OS so I can do video editing. So it will be interesting to see if going from macOS Sierra to macOS Mojave makes any difference?!

Sounds like I have you stumped, Koz?