017 The dB explained
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- Опубликовано: 30 сен 2024
- A close encounter with the illusive dB is unavoidable for all that love good sound. As with all things in life, this measure becomes more understandable if you know its background.
Facebook page: / hans.beekhuyzen
You are fucking good in sharing knowledge and does very good explanation that sounds clear and detail enough, hope you long life and don't get kill by those ppl in the industry that always make things myth and wanna sell their products, thumbs up!
+Felix Phang Tnx Felix. I will live some time more, don't worry. Spread the news.
At first I thought I was an audio nerd because I watched this twice. Then I realized if I were truly an audio nerd I wouldn’t need to watch it twice. 🤓
Great job. Great explanation style. I am subscribing immediately
Awesome video. Extremely well explained. Thanks
thanks so much for this clear and concise explanation!
one topic get missing, explaining the difference between db A weighted vs db C weighted, and when to use each one. :)
As such the weighting has little to do with the decibel. But in general A weighted is used for all things loudness while C weighting is used when low frequencies do matter more, like for instance with noise disturbance by rock concerts.
@@TheHansBeekhuyzenChannel it is correct. Thanks
Alright I don't know if you still look at comments to older videos, but now i understand what dB is and more importantly why dB alone doesnt say/mean anything unless its placed in context. For your example at 15:00, you're stating that the sound was 12dB too loud. Now 12dB doesn't tell me anything, but the "too loud" parts make me think that it is about power? And since a doubling of power is an increase of 3dB, 12dB increase is 4x louder cause 4x 3dB? Shouldn't the correct term that shouldve been used be 12dBW?
dBW is used for absolute power referenced to 1 watt. So it can't be used the way you want to use it
GREAT VIDEO!!
I have one question... You initially stated that it takes TEN times as much wattage (power) to perceive TWICE the loudness. However at about timestamp 3:20 the table shows (line two) is "TWICE as loud" (here the power level is 10W). Now to get TWICE as loud as this by making the power level ten times as much, (which would be 100W...four times louder than two times louder is "twice as loud"), why does line four indicate 1000W, rather than 100W if twice as loud as 10W is is ten times the power?
Thanks much!!
--dalE
You are right, it should have been 4.
At 3’20”, if loudness doubles, it would required 10 times of power, then 100w should provide double loudness than 10w could, thus should be “4 times as loud (as the reference level)”, isn’t it? And 1000w should be “8 times as loud (as the reference level)”, no?
Correct
Thanks for an excellent video. FYI: His name was alexander bell. Graham was his middle name. We dont usually, if ever, call someone by their middle name..
Alexander Graham Bell was baptized Alexander Bell. He longed for a middle name to differentiate himself from his father and grandfather (both being Alexander Bell). His father gave him his middle name Graham for his 11th birthday. Every paper I've ever seen signed by him is signed with all 3 names.
We still call him Alexander Graham Bell because of that importance of the middle name to him.
Hans,
Love your videos, very informational.
I have got a simple question for you.
Why is it that decibel levels on AVR's etc start in the negative DB level such as -70db
and then the number decrease towards 0db the more you crank up the volume?
Why not just start at 0 and go up to +11 or the like?
That is because they indicate the attenuation and not the gain. As explained the dB is a ratio between two values, like the percentage. You always have to consider what the ratio is. In case of your AVR it is the attenuation.
wow, u r genius in sound , never heard anyone give such explanation on sound level. thank u tons.
I loved the detailed history lesson of the Bel. But I am and have always been confused by the factor of 10 in the bel-to-db derivation. At ~ 4:07 you show the bel = log(p1/p2) but at ~4:52 you explain the dB is 1/10 of a bel and then at ~5:11 you show that the dB = 10log(p1/p2). My question is this: since dB is 1/10 of a bel why don't we divide the right side by 10 rather than multiplying by ten? i.e., since bel = log(p1/p2) then dB = (1/10)bel = (1/10) log(p1/p2).
Your further insight will be very much appreciated since this has puzzled me for several years. Thank you.
Thank you! Great job!
👍🏼
Brilliant explanation - very informative. Thanks
Glad it was helpful!
Why do most amplifiers today display volume as minus db, - why start at a minus and go up to the plus ?
+Örn Leifsson I don't know if that's true. But it's irrelevant anyway. You're lucky if your amplifier is calibrated in true db's but even then they are only a relative indication unless the manufacturer specifies the reference (what I have never seen). Still, you can use it as a relative reference - let's play that 6 dB louder.
+The Hans Beekhuyzen Channel - OK - I recently bought a new Pioneer amplifier (vsx 930-k) and the volume goes from -80db to +12db and a comfortable listening level is around -30db - it just looks so strange to me.
+Örn Leifsson OK, let's say you connect a cd-player that gives 2V output max. That's +6 dBV. And you connect an old tuner that outputs 0.315V, that's -10 dBV. hen you switch over from tuner to cd-player the output of the amp gets 16 dB louder without you touching the volume control. Now, let's assume your speakers do 89 dB/2,83V/1m and you play one watt.
Now you hook up a set of horn speakers that do 103 dB/2.83V/1m. If you still play at 1 watt (so you didn't touch the output nor change the source), the acoustic output is increased with 14 dB. If you now select the tuner, the loudness goes down 16 dB and you end up only 2 dB louder than playing the cd-player over the 89 dB/2.83V/1m loudspeakers. ALL WITHOUT CHANGING THE SETTING OF THE VOLUME CONTROL. The indication is mere window dressing. Looks nice though;-)
Thanks for the video, the reason I watched you video was to figure out the minus dB, I think it's some sort of dBfs (Thank you for explaining this concept) as just audio systems with digital volume knob (not a simple potentiometer) use this kind of representation. also in video cameras, as the audio is recorded digitally the level bars are shown from - levels up to 0dB and the important levels that usually camera mans tend to keep the audio level is between -20 to -12 dB as if the level reaches the 0 dB it means all the bits of audio wave variable is set to 1( the variable reached the maximum possible amount) and we have actually a flat signal. I also read somewhere that digital audio equipments are calibrated so that what they show as 0dB( that i think is some sort of dbfs) is just the calibrated level and is something around 75-105 dB in the audio world (don't know if it's the power or sound pressure) and It seems rational that many more powerful systems have also positive dB to show as you turn the volume knob up, It just produces dBs higher than 75-105. am I right? what do you think about it?
did anyone jumpet to the timecode? i don't think so.. :))
Statistics show you’re wrong. Why the negativity?
@@TheHansBeekhuyzenChannel i was saying that the video is so captivating that i don't think anyone skipped some part of it :) it's a compliment
I wish my math teacher was you! Explain by a story and very useful... thanks for the great work!
🙏🏽
Hi! I am new to all of this, and I learning a lot from your channel. I am currently building a 5.1 system with B&W 685 S2, 686 S2, HTM62 S2 and an SVS 12" 300W Powered Subwoofer. I am trying to match it the best I can within my budget and I
have 3/4 options that I could think so far :
1. Outlaw Model 976 Processor & Outlaw 5000 Power Amplifier
2/3.Marantz SR 6012/SR 7012
4. NAD 758 v3.
I love to listen to music, but I like movies as well. What do you think would best processing/amplification option to match my speaker system? (86-87db sensitivity). If I am in the wrong place to ask this kind of questions, would someone, please, direct me to the right place. Thank you in advance.
I have no reviewed the Outlaw and Marantz but I do use the NAD now and love it. Especially the improvement Dirac brings is great.
Thank you very much!@@TheHansBeekhuyzenChannel
Thank you for the great explanation! :) I just have one question regarding the last example (the pub owner one): If he broke the law by 12 dB, doesn't that mean that he was 12/10 (B) +1 = 2,2 times too loud and his sound pressure level was four times the permitted one?
No, you should - for power - divide 12/10 to get 1.2 Bels. For voltage divide by 20. Then take the 10 based root and then you get the ratio. For voltage . The easy way: for power each 3dB more is a doubling, for voltages each 6 dB more is a doubling. So your outcome was correct.
I watched this video (again) trying to get a better understanding of a new unexpected problem in my set. Recently I bought a two track tape deck in order to play (copies of) studiomaster tapes. The tape deck only got two 3-pins XLR outputs. With very simple adapters from XLR to RCA out I connected my tape deck to my amplifier. The problem is that the output signal from the tape deck is much to loud now. If I am correct, XLR out should be 6dB louder than RCA. On my amplifier I have 3 RCA ports IN. Port 2 is in use by the tape deck. RCA Ports 1 and 3 are possessed by other devices. When the tape deck is playing on 2 and I switch to RCA 1 or 3 I still can hear the music of the tape deck. Not as loud, but still... Perhaps a pre amp with XLR inputs would solve such “overflow” problems, but my integrated tube amp only has RCA inputs. So what would be the ‘second best’ solution to solve this XLR -> RCA = “+6dB” problem?
Levels in professional tape recorders are a bit complex. They are set for a given output voltage at a given magnetic level on the tape. And since reference levels on a tape can vary between 180 nWb/m to 512 nWb/m, which at its own is a variation of 9 dB's. Then the output voltage at that given reference level can be set to a variety of voltages, traditionally +6 dBm at 0 VU was the reference. In any case, since the tape recorder has XLR's I presume it must be a professional deck in which case the output voltage can be lowered by varying the replay level. Usually this is done by small potentiometers on the replay PCM in the tape recorder.
Thank you very much for your explanation! My tape deck is a professional ABE WG 31 with a brand new Telefunken M15 reading head. In case “the output voltage can be lowered by varying the replay level”, maybe I could make use of a pair of Rothwell attenuators (-10dB) and put these adapters in between the RCA interlinks and the integrated amp or putting a (Schiit) ‘passive’ pre amp in between (causes a ‘loss’ of at least -5dB at maximum volume level, up to....) instead of “modifying” the tape deck internally. Would you consider such solutions to be a simple alternative for potentiometers inside the deck?
I just wanted to know how loud is 80, 90, or 100 dB, and if +1 dB is actually double the loudness.
Please watch the video again.
Excellent explanation. Great production values.
You lost me at my name is Hans
Sorry to hear. But then again, you don't need this to enjoy the music.
hahahahaha lol 😂
Hi Hans, thank you for another great video.
Some people use an SPL meter for audio setup or when talking about how loud they listen. When I try to relate to other peoples explanations, I always wonder if they talk about dBA or dBC scale. They do result in quite a difference in readings as I understand dBC looks at a broader curve.
Without looking into a super deep understanding of each scale I am mainly trying to find what is most commonly used when someone in audio refers to the dB SPL they listen to so that way I know better which scale I should use on my meter to have a better comparison to which SPL listening levels are referred to.
As such both can be used but usually A weighting is used.
@@TheHansBeekhuyzenChannel Thank you!
It was like getting a drink of water from a firehose, but very useful nonetheless.
What I like about videos is that you can replay them over and over again😄. But I get what you're saying.
your dutch Hans? real good video's!
Guilty as charged:--)
Excelent description
Interesting lesson thanks
just awsome :) thx
You're welcome!
Awesome as always, thanks. I think deci is dieci in italian/Latin that means 10
correct
Thank you so much!
Great explanation, Hans. Thank you!
+Beryl Green Thank you Beryl
That's why i respect seniors (y)
What seniors😀
Your video made me pass my interview so..:D
sorry😗
Awesome