Decibels (dB) In Audio | The 5 Things You NEED To Know...

0:00 - Introduction
0:03 - 1. Decibels Are Ratios
1:50 - 2. Decibels Require A Reference Point
3:57 - 3. A Decibel Is 1/10th Of A Bel
5:16 - 4. Decibels Are Power-Related Ratios
6:47 - 5. Doubling Power, Pressure, And Voltage

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[soloperformer]

I do hope that the many people who use the dB, without being aware of what it actually is, view this well presented video.

[clevermissfox]

Very concise and simple for us YT knowledge seekers. Will have to watch again but definitely have a better understanding and beginning to grasp the concept. Thank you dear sir! You have been crowned… the Bel King 👑

[simon-d-m]

Point of nerdy detail: dB is always only a ratio unless it has a suffix. For example, dBa, sometimes written "dB(a)", means the A-weighted scale of sound power. That tells you the reference point (zero dB), and because it's sound waves, it also tells you that it's the A curve, which models the frequency response of the human ear. There are other curves used too, for expressing sound power in dB, but this is the most useful one, which you will see on level meters etc... On this scale 3dB is a halving or doubling of sound power.

The other common one is dBv (yup, voltage decibels), where 6dB is a halving or doubling, as you said in the video. This is almost always the scale you find in the audio chain (amps are the exception!).

There's a bit of history behind this - back in the day in telecoms and broadcast and valve signal amps, the engineering approach was to optimize the POWER transfer between source and destination. This gave least noise/interference, cleanest signals, etc., and (later) it was one reason why Neve's modules have transformers on each end (inside the desk!).

Optimized power transfer is still necessary in some places: radio transmitters and receivers (aerial feeds), record stylii, guitar and other instrument pickups, and all forms of magnetic recording heads (analogue and digital), etc. For everything else we use dBv, and the principle of high-impedance inputs (very little current flows - the input stage is designed to amplify the voltage it sees).

Also useful to know (when dealing with dBv), is that a signal change of about 1.5 to 2 dBv is about the smallest the human ear can detect (when it's turned into sound). I've worked with colleagues who claimed they could hear 1dB on line-up tone, but the best thing was just to smile sweetly and change the subject!

You ought to do a video on impedances - mics, instrument transducers, DI boxes, input vs. outputs, etc., and about balanced vs. unbalanced signals (single-ended vs differential in the digital world). The more people understand the easier it is to do the job well. Of cource you can nowadays just plug stuff in and it works, until it doesn't!

[mitas]

I just wanna thank you for making these videos, I’m new in this complicated business and was recently volunteering at a gig in my town. I binged your channel before the event, and now I manage setup and tear down at my second event this weekend. I think you’ve managed to squeeze years of experience and classes into days, amazing!

[dailysiren]

Thanks. This video helped me understand these audio measurements a little bit easier since I'm one of however many people in the world with sensory issues. 👍👍👍

[TracingFlares]

i think a useful adition to this would be the fact that you can select multiple faders in your mixer... each one with a different value.. and if you turn them down or up simultaneously they will keep the right proportion from the mix. Means: do not automate volume in your tracks. Automate or set output of your plugs... then if you hit the master above 0 db.. you can simply select all tracks and turn them down in the mixer simultaneuosly (provided that each one is not clippin... i think a video on this would be highly useful. 😊

[dewaadrian]

Super Awesome.
This is what Audio Enthusiast need to know.
Thanks Kyle for every free lecture.

Let's share this channel, guys...!

[macronencer]

Finally, someone explains clearly why the number 20 is used. I've been baffled by that for so long... I'm gaining so much from your wonderful videos – thank you again, and sorry if I'm spamming your notifications. I'm working through your back catalogue :)

[EnriqueRojasmusic]

Wow, I have been working with audio for many years and never realized the depth of the Db unit by all its variations and applications. Thanks for this great video!

[phillipabramoff]

The chart at 0:50 is the most helpful part of the video.

[flaviozarza]

Definitely, this is maybe one of the best channel that audio & sound community can find on Youtube.
Thank u so much for sharing your knowledges with us.
Regards from Bcn!
🤘🏼

[vedvy]

Thankyou. while I have done lots of audio for theatre etc, I'm also quite involved in radio. I mean on the radio frequency as in the what the transmitter antenna and receiver. these to although not audio but at radio frequencies is also expressed in decibels. your explanation applies quite well since the ratios are the same concept to radio frequencies. to increase my signal by 10db I increase transmitter power by 10 times. using AM radios with any gain compensation turned off a 10db increase of the radio signal will as I say without AGC or automatic gain control to compensate for changes in signal strenth, will also make a 10db increase in audio volume.

interesting how the bell or decibel can be and is often applied in other things other than audio.

[korkenknopfus]

Very nice explanations at the Audio University.

I could complement with a fact that serves as reference: speaking of sound pressure level, if you hear a sound at a determined level, when a second sound comes in, that sounds 10 dB louder or more, you will be hearing only the second sound. That explains why you can hear a dog barking in you neighborhood, but if a track drives near your house, you can’t hear the dog anymore. Well, my cat claiming for fresh fish you would hear him anyway, but he is an exception to laws of the physics and the logic.

[nedim_guitar]

The channel name Audio University makes sense. Very informative.

[joacox]

the best explanation I found regarding this topic

[scarecrow]

Hello. An Electrical Engineer here. Pretty good video.

One slight comment. A decibel is 1/10 of a Bel not 10 times a bel. Also, Wikipedia starts with.

“The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B).”

[mikebauer]

Great explanation. Thank you for not holding back on the math.

[alanhilder]

In sound, 1db gain is the smallest change in sound you can hear, 3db is only a slight change in volume but takes twice the power ( amps and speakers ) to produce.
It is also dependent on distance, twice the distance half the volume ( I don't know the readings of that, but aprox. half the power, -3db )

[mennims]

This is actual information, subbed.

I like Paul from PS Audio, but a 7m video is primarily good vibes, history and some information, and yet I see many people Commenting "wow so much useful information this was amazing".

[Noetica]

The best video about decibels and the best creator for audio tecqniques. Thank you!