What is Dolby Noise Reduction? Dolby's Humble Beginning

[@blendpinexus1416]

this video literally explained what the dolby button on my 2001 mazda mpv's media stack did. wow.

[@ThePrufessa]

So is that a bad or good thing?

[@blendpinexus1416]

@@ThePrufessa good thing, i never knew what it did until now. i just know the sound changed but i didn't know what was going on to cause a sound change. Keep in mind the "Cassette" i was using was a high quality adapter for use with phones and the likes so there was already a very small amount of noise to begin with.

[@adisar2002]

BlendPiNexus he just made a video on those :))

[@ThePrufessa]

@@adisar2002 yep it's in my feed today! I haven't watched it I pretty much know how it works.

[@blendpinexus1416]

@@adisar2002 he did? SWEET!

[@elesjuan]

Dude this stuff is GOLD! You earned a new sub after the VHS video! You present technical content in a very intelligent form without boring the viewer. You're VERY well spoken and don't ever drift off the conversation, yet still have a hint of dry humor. I love this!

[@mephitusincognito7918]

his technical explanations aren't very technical but at least hes not faking it like the ibook guy... er '8bit guy'

[@bricegraham8256]

What the odds another car guy is watching this. I randomly came across this video as well bcs I'm Abit into tech and I literally felt the same way about him as you did. He uses big words but insane words that go completely over your head and he explains everything in case your a normie who didn't quite understand which in some cases we all are lol

[@nomadic_shadow]

I agree man

[@nineball039]

I used to fix this stuff for a hobby. Today's consumer electronics are not designed to be repaired, use impossible to find (and see) tiny parts and SMD technology.

[@ilesoft82]

It seems that I have already subbed and liked this video. I guess there´s nothing else available than to become a patreon.

[@gurutonic]

It's amazing how much this channel has improved over the course of a few years. The content has always been excellent, but the filming, delivery, and production quality have really come a long way since this video was uploaded. Thanks!

[@WreckedRectum]

That bow tie is FIRE 🔥 though.

[@McSynth]

Even as a musician/engineer, this is the most lucid and straightforward description of 'Dolby B'. More power to your channel !

[@planetrob555]

...and that over-emphasis on the treble sound is what I loved back around 1982 when I was recording my first band. I'd record using Dolby, then mix the final, from a TWO TRACK cassette deck, WITHOUT Dolby so that it was crisp and bright.

[@007bistromath]

Bring that Dolby C recording down to half speed and lay some Japanese mall sounds on it and you've got a vaporwave summer hit

[@imsomlgmiku5752]

lofi

[@chrismanuel9768]

I would literally listen to it on repeat

[@crashputer]

You should do a video on the RIAA curve and how it solved the problems of recording high fidelity sound to records and helped establish the 33 1/3 rpm standard. Keep up the good videos!

[@mescko]

Excellent idea!

[@robkilpatrick4283]

I'd love to see this video!

[@RazorStrap]

And also the use of pre-emphasis on CDs in the early days of the digital era. And the roll it played in people bashing CDs for being harsh sounding.

[@edised71]

What a shame we didn't have videos like this to tell you all about Dolby when we needed it the most!

[@mikeroadblock]

Yeah. Times change about sharing and tech. Watching it “now” is like an archaeologist with regret. Cheers!

[@RMoribayashi]

The companding in Dolby noise reduction is more complex than just setting an equalizer. The companding is accomplished by varying the volume of the desired bands *_depending on how loud they are!_* That means it _changes over time._ The Dolby playback circuitry has to sense when to change the volume to match the amount of change during the making of the tape. That's the real reason for the Dolby sign on the level meter, record levels need to be set to match the preset playback settings. A mismatch can sound like there is a pumping or breathing effect to the sound.

[@kennethbouchard8643]

You can build your own dolby encoder decoder, by robbing parts or using those Dolby Symbol IC chips. Or modify a tape deck. You could even purchase in the 70s add on boxes to convert a normal tape deck to dolby. DSP boxes now offer even more ways. Everyone had a gimmick in hopes of marketing solutions to those problems. And of course now most sound cards, and computers offer DSP processing to alter live sound.

[@RMoribayashi]

Back when Dolby tape noise reduction was passing into history. Dolby inc. had the good sense to get into multitrack encoding in time for the explosion of 5.1 movie sound. While it's not what it's made for, I still haven't found anything that does a better job converting 2 channel stereo to 5.1 than the Dolby Pro Logic surround circuits built into my over 25 year old small home theater speakers. They're a bit long in the tooth so I'm hoping to find a halfway decent DSP plug-in since most of my music collection is 2 track.

[@nathanmead140]

@@RMoribayashi does it work with the psp?. A couple of my games have D.P.L.2 but i don't have a way to play them in 5.1 or 7.1 surround sound

[@electricpalace4720]

@@RMoribayashi Dolby first got into movie sound as early as 1972, only 7 years after the founding of the company, when they used Dolby A noise reduction on 35 mm film prints. These Dolby prints also used equalisation to improve the frequency response of the track. The system was not commercially successful as movie theatres were reluctant to spend the cash needed to upgrade their sound systems. However by splitting the sound track in two, each with Dolby A noise reduction and adding the pro-logic decoder, Dolby created Dolby Stereo. First used in 1975 on "Lisztomania" it soon became the de-facto standard sound system for 35 mm film prints and remained so until the introduction of digital sound on 35 mm prints in the early 1990s. Right up to the replacement of 35 mm film in cinemas with digital projection,which occured in the 2010 - 2014 period, 35 mm release prints all carried analogue Dolby Stereo tracks as well as digital sound data.

[@videodistro]

Exactly! Most people, including this KZbin, don't know this. If you worked in professional recording as I do you would learn this.

[@raydunakin]

I was a hardcore audio tape guy for ages, and always used Dolby. Until now I never knew much about how it worked, I just knew it did. One of these days I need to find a decent USB tape player so I can transfer some of my old stuff into digital.

[@darinb.3273]

DON'T I'll explain. You current cassette decks will work beautifully for the task. If you plan to use your computer as your digital recording source, use the line in on the computer sound card Audacity is completely free to download and use as the recording software. Those USB tape devices are garbage and WILL NOT do your prized recordings justice. The biggest catch is ANY NEW cassette tape machine has no Dolby because it is no longer licensed. You can search for an RCA (connect to your tape deck) to standard mini headphone jack (plugs in the line input on your computer). Set the recording levels to about 75% below the ZERO decibel mark in Audacity (no clipping) and afterwards you can normalize your recording before permanently digitally saving it to your computer. Hope this helps 👌😄😃.

[@raydunakin]

@@darinb.3273 Unfortunately the good quality cassette deck from my old component stereo system no longer works. The only other player I have is a boom box that doesn't have outputs.

[@darinb.3273]

@@raydunakin Awe man sorry to hear that, I made an assumption your cassette machines still worked. Any idea what's happening with it/them? It may simply be in need of new belt(s). Any details you can provide you and I may be able to get 'er pulling tape through her again.

[@raydunakin]

@@darinb.3273 Thanks. I'm not sure what's wrong. The whole system stopped working about 15 years ago and I couldn't find any place that still does repairs. I suspect the problem is actually in the amp, which provides power to the tape deck.

[@darinb.3273]

@@raydunakin Ohhhhh one of those type systems that relied on the Amp portion to supply power? Not a TRUE component system in other words. As I understand a TRUE component system is everything can work independently and mix and match with ANYTHING that had line in and outs. It maybe worth checking to see if you can determine the voltage requirements for the cassette portion if it is separate and still get much better quality than a USB attached device. Techmoan as well as many others have reviewed those wanna be cassette players. Of course another option is to find an older machine for sale somewhere thrift stores and yard/garage sales. Never know what you may stumble across. 👌😄😃.

[@PanamonC]

The remarkable ease with which you explain these sometimes difficult to understand subjects never ceases to amaze me. Definitely appreciate your work!

[@shableep]

This video is SO GOOD! Having your voice being fed through the actual mechanisms is so informative. Showing the actual effect of the EQ in "real time" illustrates everything in such a clear way. And then the alliteration? GOLD, JERRY! GOLD!

[@atmel9077]

Note that a similar system called "pre-emphasis" is used in FM radio, because the noise induced by the transmission lies in the higher parts of the spectrum. The trebles are boosted before transmission then put back to the normal level. On varions wireless audio systems (cordless phones, microphones, headphones etc...), companding is used to overcome the noise that would affect the quieter parts of the signal, by using nonlinear amplifiers.

[@packindarkies2103]

Your channel has made me so nostalgic. Would spend hours listening to my music watching the tape go around. Staring at those pumping lights. Wondering what those switches did. Feeling Techy-As-Fuck just pretending I knew their function. Keep them coming....

[@robertgaines-tulsa]

Only 320 likes in four months? This channel must not be widely known yet. Nice vids! More people will notice them in time.

[@v1nchynoobs]

another 1300 in one month though!

[@jacobrzeszewski6527]

7.3k in two years. Yea, he got noticed.

[@jonbridge5133]

@@jacobrzeszewski6527 over 8000 now

[@nathanmead140]

9k

[@pietro_tino]

11k (and I'm one of them)

[@7h3hu7]

Obviously your videos are amazing, but what I really love is the understated deadpan comedy. So many other videos have over-the-top slapstick, but your subtle comedy is refreshing and doesn't detract from the info being presented. Well done!

[@richard7crowley]

Before Dolby Labs, Ray Dolby started out at Ampex on the team that developed the first widely-successful video tape recorder, the 2-inch quadruplex Ampex VR-1000. The development of the first commercial video recording (quadruplex) would be another fascinating episode. Keep up the good work.

[@edgarlee2802]

I've just bought a Sony cassette deck and this has answered all of my questions. Thank you.

[@JacobFrey]

I hope to see many more videos like this one, and I wish you many thousands of subscribers.

[@utfigyii5987]

Maybe billions

[@JEMHull-gf9el]

....trillions

[@ngaswithadditude]

Million.

[@richiezombie531]

They should play your videos in certain schools and pay you for the right to. You are an excellent teacher. Thank you for your hard work.

[@HermesMatamoros]

Thank you, first time I EVER understand how noise reduction works!

[@mjs8624]

Subscribed recently, some people couldn’t care less about this stuff. They just want to see their t.v. and hear their music. being into audio for the last 15 years and hooked on old tech I couldn’t be more fascinated by your videos. Thanks

[@panicwire]

I'm really enjoying all of your videos. Your cadence is very pleasant and easy to listen to for long periods. The presentation is easy for anyone to understand as well. Love it! Question: have you considered making a video on the ADAT format?

[@alexriesenbeck]

I've been recording with cassette tapes ever since I was little and never took the time to understand how Dolby NR works... You are excellent at presenting this information, I really enjoy your videos. Thank you so much

[@thee_number_six6227]

Love the layman's term breakdown, good presence. Been watching a few of your vids all day. you got a sub here

[@andrewdenson]

This is one of the best channels I've discovered in a very long time.

[@petersage5157]

Dolby B is essentially the reverse of RIAA equalization, in which bass frequencies are attenuated during recording to better fir them on a record groove and boosted during playback to compensate. I'd love to see a companion video on this. It would be great if you could also include a section on why ceramic cartridges don't require the RIAA bass boost. (I've studies this in detail, but this was back when vinyl was still the mutt's nuts, so my memory is a bit rusty. Something about ceramic cartridges being inherently less sensitive to higher frequencies.)

[@8MoonsOfJupiter]

Great work - really enjoyed this, not only for the detailed technical information you provide, but because of your delivery! Keep em' coming!

[@beitie]

Back when Dolby was popular, I was just starting my interest in audio electronics. I made many recordings with cassettes on my Dads Technics tape deck (it was a mid 70's model that did type I and II tapes, and only Dolby B). Like many here in the comments section, I prefered to keep Dolby off. However, now that I'm in my 30's, and have been able to get back into high end audio equipment, I find that I prefer the Dolby when it comes to pre recorded tapes at least. An example; I recently bought a NOS Bon Jovi - New Jersey cassette (1988 album). It was recorded on what appears to be Metal (type IV) tape. It has Dolby HX Pro (a system that should work perfect with my Bang & Olufsen Beocenter 9000's cassette deck), but no Dolby NR. I compare that tape to my mid 90's cassette of Weird Al's "Even Worse" album that is type I tape WITH Dolby B NR, and to me, the Weirs Al tape wins in that sound test. Sad really. I think Dolby B was a great thing, but cheap consumer decks didn't have it, and that was the eventual fall of it, and all music formats really. It's my theory that record companies want to push the album out to as many consumers as possible, and since the vast majority have cheap systems, with sub par amps, speakers, ect. The majority of the media is meant to play best on those systems. It really sucks for people like me who really enjoys music, and has put a lot of time and effort into my music listening set ups. /rant

[@jamesisaac7684]

I prefer Dolby over DTS. But most of their equipments are non backwards which is what I hate about them.

[@nathanmead140]

Its not ect it's etc

[@gerardoromano3436]

I know this video is old but explains Dolby NR in a simple way that almost anyone can understand, the key off this presentation is practical examples. Good Job! No wonder you have 2.24 M subs

[@trevekneebone369]

Brilliantly well explained - bravo!

[@b-macjsp3550]

Idk why but.. 5:49 looking at this cassette tape is really nostalgic to me, very satisfying. My parents couldn't afford a camcorder but discovering audio cassette recording was a big part of my childhood. Where the audio recording took place like parties in such, I remember the exact situation in mind and playing the audio in reality it was like a video camera to me (with imagination). Nobody understood the kid with a boombox but that was the only entertainment I fully enjoyed. Didn't mean to throw a story but I simply enjoy your content vid by vid, very glad to be a subscriber.

[@rquance1]

Take a look at how FM radio is run through a preemphasis system at the transmitter and then a deemphasis in the tuner/receiver. This is how most of the early Dolby was designed in the prototype tape machines. I used Dolby B, C, and DBX in the Radio stations I worked at. DBX was the best for Broadcast work since it processed the whole frequency range of the tape at (normally) a 2 to 1 compression ratio and then expanded it by 1 to 2 on playback.

[@kennethbouchard8643]

Yup, I had a couple of tape decks, that offered Dolby FM and receivers that had Dolby FM decoders built in. Even 8 track would have been better with Dolby. Very few FM stations did broadcast in Dolby FM. The investment of that never paid off, as FM only has limited dynamic range. 15khz top end by FCC standards.

[@Solitaire001]

Excellent video, and one that caused me to subscribe. I never had an issue with Dolby B noise reduction, if a tape was encoded with Dolby B I played it back with the noise reduction. With one exception, I never noticed the "killing the highs" issues that others have mentioned, but I think a factor in that is that I used good-quality cassette decks with high-quality tapes. The exception was with some cheap pre-recorded tapes.

[@langreeves6419]

I used top of the line. My cassettes sounded sooo much better than commercial ones. But there was a way to make crappy sounding cassettes Record them with Dolby B or C. It would my cassettes sound as bad as the commercial ones. That was using varied recording levels, and over a period of time, 2 or 3 different tape decks, and different types of tapes. A little tape hiss was well worth having a good recording.

[@RMoribayashi]

Dolby A came out just as multitrack recording was really taking off. Many of the best recordings of the late 60's onward would have been impossible without it. Take 1968's triple-Grammy winning Switched-On Bach. Recorded on an 8 channel recorder back when synthesizer keyboards could not play chords, this meant recording each line of music to a single track, mixing the filled tracks down to free them up then doing it all over again. Without Dolby A's noise reduction this track bouncing would have increased the background noise until the tape was unuseable. Instead it won the 1970 Grammy for Best Engineered Album.

[@noop9k]

RMoribayashi modular synths aren’t “keyboards” and most can’t play chords to this day.

[@RMoribayashi]

I've played and owned synthesizers since the 70's and like all my gear I've always called them keyboards, including the modular ones. As for chords, I meant that there were no commercially available polyphonic synthesizers back then.

[@oisiaa]

Your channel is AMAZING! I love the detail you go into for seemingly tiny and random things!

[@corri303]

4:30 I disagree. This process is called "preemphasis and deemphasis", not companding as an equalizer does not alter the dynamic range. Companding is the combined use of dynamic compression and dynamic expansion, hence the name companding (compressing/expanding)

[@misterhat5823]

It's actually doing both. By varying the amount of pre-emphasis, the high frequency portion is compressed on record. The opposite occurs on playback. As others have mentioned, this video glosses over a lot of it. Kinda like "Dolby for Dummies."

[@videodistro]

No. Some noise reduction is preemphasid and de emphasis, like what is used on an FM modulator. However, the better more sophisticated NR was compassion and expansion.

[@StefanReich]

@@videodistro Compassion? LOL

[@rods6405]

Totally correct! Saved me typing it again! I cannot believe all the suckers that blindly believe this guy without even a quick web search!

[@PedallingwithPaul]

This was good to know. I never questioned why sometimes when turning on Dolby sometimes made stuff sound better and others just got quite.

[@rEdf196]

Cool I got that Technics M218 tape player in the early 1980's it worked really well for 15 years.

[@gmax341]

Are they really good decks? I'm looking to buy a really good deck to record on metal tapes.

[@nathanmead140]

If you still have it i might be able to fix it if it's broken

[@sjerkins]

A companion technology to Dolby for professional pre-processing for mastering was the first baby steps in DNR tech... digital noise reduction. The first studio units were starting to show up in 1978. The circuit was actually so simple that we built one for the college radio station. You directly couple an analog to digital converter with a digital to analog converter. That will take out 40-60 percent of extraneous noise and tape his from field recordings so you can get a clean master for broadcast. It was great for local, next day, broadcasts of away sporting events.

[@filipesaz]

Funny... I cannot hear that cassette noise. So then I remenber: "Ho yeah, my tinnitus!" . . Yup, this thing "sings" louder than that annoying cassette tape hiss, (that I still remember from the old times). But with regards to the tinnitus... well, like my doctor says: "Just forget about it". . . And then he adds: "But if for some reason, some day you can't forget about it anymore, then come back here, I will prescribe you some anti-anxiety pills to help you forget about it". . . So yeah, here is my piece of advice: "Stay away from tinnitus". If you can.

[@elephystry]

Fil Ipe how'd you get it?

[@filipesaz]

My tinnitus just started to gradually appear out of nothing, with no apparent cause, around my 35 anniversary. I am sure it has a cause, but it is unknown.

[@elephystry]

Sorry

[@mdm5216]

Could be stress related. When mine started it was so bad I wished I was dead. After 10+ DR's I did my own research. Basically had to cut the stresses in my life. Still there after 4 years but very tolerable.

[@texarcana2002]

You and me both. Mine sounds liek a million crickets all chirping nonstop... actually, I take that back: mine sounds EXACTLY like tape-hiss. That might explain why I hate Dolby NR: I rarely ever had it in my equipment (usually due to monetary scarcity), and tinny-sounding recordings just set my teeth on edge. I like balanced recordings, and I like hearing the bass parts as well as everything else. THe hiss was usually not a huge problem for me, as i would use high-quality tapes (cheaper than new equipment), and I would make sure I saturated them properly with the recorded signal.

[@ElDJReturn]

You are my favorite nerd on KZbin! Sincerely, A Fellow Nerd.

[@ka7hqp182]

Dolby is much more than as explained in this video. While it does alter the equalization during record and playback, it is applied dynamically depending on the level of the content. Most tapes that resulted in poor results with Dolby were the direct result of the levels being set incorrectly, and low quality tapes being used. In addition most lower priced cassette decks produced excessive hiss, even without a tape, due to the poor design of the player.

[@kennethbouchard8643]

Very much true. The video seems to make it sound like it is just boosting the high frequency levels, but it is dynamic based on the content and not the overall signal.

[@oldager1662]

He does start mentioning the companding around 4:30. But you are right - any deviation in level or high end frequency response would cause Dolby playback to sound really bad. I think a lot of users used Dolby to record, but turned it off on playback!

[@videodistro]

YES, exactly. Working in pro audio for 40 years including through the NR years, I can attest that this is correct. This video is only partly right and full of errors. But he tried hard.

[@VisionThing]

This is the coolest channel!!!

[@RamLaska]

Egad, that's so simple! I always wondered how that worked!!

[@videodistro]

It's much more complex than simply raising and lowering EQ curves. It also included compansion and expansion of the signal. This video is sort-of right.

[@Cypher791]

i never understand anything from any of these videos but.. i keep watching

[@elbiggus]

It's a wonder nobody came up with it sooner -- it's almost a natural extension of the RIAA curve used on vinyl. (The RIAA curve is also reason #247 that vinyl does *not* sound better than digital, but that's an argument for another time and place.)

[@kennethbouchard8643]

How good something sounds is a personal thing. I can play music on a gramophone made by Edison, and some would marvel and say wow that is great, and others would say it sounds worse than dixie cups and a string. Fidelity is all as you perceive it. Some like it loud, some like it soft, some do not care. You can achieve fidelity with only 1 watt of power, and you can achieve fidelity with 1000 watts of power. You can have earbuds, and you can have concert speakers. You can scramble your guts, or you can scramble your mind.

[@McGuinty2]

Really, the biggest reason that someone would say vinyl sounds better is that they're listening to a poorly mastered digital recording. Other than that it's a matter of taste. I have some LP's that I prefer the sound of to newer digital remasters precisely because the original master was done by someone who knew exactly what sound they were trying to achieve 40 or 50 years ago, plus the mastering and mixing was all done with an analog path, which definitely has a unique sound compared to some newer LPs I have that were cut from a digital master and sound almost indistinguishable from a CD pressed from the same master (at least the first few times they're played). I'm also skeptical of anyone who claims an audible difference between CD red book audio and any of the high resolution formats. The specification of CD audio with respect to dynamic range is pretty close to the limit of what we can perceive and well beyond even the most dynamic recorded music, and the sample rate is just beyond the highest frequencies we can hear. The only reason they use more in the studio is to have headroom to avoid clipping and distortion before it is mixed down and mastered for distribution. The only reason I have any SACDs, DVD-As or Blu-Ray audio discs is because of the alternate multi-channel mixes found exclusively on those formats.

[@Zaparter]

Right, CD redbook audio facilitates maximum fidelity -> xiph.org/~xiphmont/demo/neil-young.html In a listening test by Boston Audio Society, no one was able to tell if a CD standard A/D/A conversion is inserted into 'high-res' playback. Even without dither. It's honestly quite insane, thinking we have an absolutely perfect way to distribute stereo recordings, yet 99% of music released (independent releases probably ~80%) is pressed firmly to the 0dBFS limit. To varying degrees of listenability. Some early loudness war icons, such as Californication, with excessive amounts of hard clipping, are not even as loud (in RMS level) as most new productions with multiple stages of multiband compression and limiting. Yet the newer stuff inarguably sounds much cleaner. Getting into vinyl for old pressings is often the only way to get a satisfying reproduction of the original master. CD standard conversion hasn't been were it got only after the loudness meme started, and picking up original CDs can be hard (even finding rips).

[@DaleC1980]

No, that is wrong. Just because someone subjectively likes an analog sound better, that does not mean it has better fidelity. Digital recording has better fidelity. Period. However, the imperfection of various analog formats are pleasing to a lot of people. But they're still imperfections. Here is a good exercise, take a CD. Copy it to a tape. Guess what? It will now sound like a tape. Take a prerecorded tape, copy it to a CD. It will still sound like a tape.

[@MichaelRei99]

DaleC1980 sounds like the reply of a data geek not someone actually listening to the music. Big difference.

[@mikedench1110]

These are very good technical explanations. You are an excellent presenter with a nice voice.

[@ajonescouk]

I know it's quite a bit more modern, but it would be interesting to see a video on how SRS virtual surround sound works.

[@ZeedijkMike]

Nice to see a good old Technics tape recorder. Still using my Technics amp. bought back in 1986

[@Lightblue2222]

I rarely used the noise reduction. Sure it got rid of the fuzz but it also muffled the sound. Edit: I should watch the video before commenting hehe.. I wasn't recording properly. Nice to know the way around the muffle.

[@snapsnappist4529]

Great video. I always regarded Dolby NR as working on the same principle as the RIAA curve employed on vinyl records. Records are cut with the treble frequencies boosted and the bass frequencies cut. This solves two problems: the boosted treble helps to "mask" surface noise like dust and scratches, and the bass cut enables longer running times, as the side-to-side "groove wiggle" needed to produce bass can be made smaller, thus making it possible to cut the grooves closer and increase running time. As the RIAA curve was standard, and every phono stage worked in pretty much the same way, vinyl never had compatibility issues, and never really required consumers to upgrade their equipment. There was a slight shift when the move from mono to stereo took place, but the EQ curve was the same, and mono records were playable on stereo cartridges. Stereo records could even be played on mono equipment, as long as a stereo cart wired for mono was used. Of course, DBX was arguably a superior system, but it required buying a new decoder and not many records were ever issued on this format. If I remember correctly, the original Dolby A, developed for use in professional recording studios, was developed as a solution to the problems inherent in the growing complexity of studio recording. As far as I know, noise reduction wasn't really used in the 50s and early 60s because it wasn't really necessary. In the early days of studio recording to tape, music was cut mostly live to 1- or 2-track tape. In the case of these machines, the tape could run at 15 to 30 ips and used much wider tracks, both of which generally eliminated problems with bias noise. The Beatles made all their records on 2-track machines until they upgraded to 4-track on A Hard Day's Night. The problems with increasing the number of tracks on a tape is that the tracks become narrower and the bias noise gets louder as the individual tracks are added together. Fast forward to the 90s, and most professional studios had tape machines with 24 track head stacks. 24 tracks on 2" tape = very narrow tracks. 24 tracks of combined bias noise = lots of hiss. Dolby B was one of the technologies that elevated the humble cassette into the realm of near-HiFi. A pretty amazing achievement, given that most tapes were basic Ferric Oxide with narrow tracks running at a very low speed.

[@Pazuzupizza]

6:19 Accidental Vaporwave

[@vk3crg]

You've turned the ability of turning complex concepts into language everyone can understand into a fine art! Working in the technical side of broadcasting and TV myself for 30 years, and now on-air in commercial radio, I know what you do, turning really complex theory into something anyone can understand is not as easy as it looks. I also train candidates & sit people for their amateur (ham) radio exams and often suggest candidates check out some of your videos. You're not "stuffy" or tedious to listen to and explain things really well. Well done! Craig - Australia VK3CRG

[@wrentubes1886]

Dolby C sounds a lot lot like a hyper compressed loudness war mastered recording.

[@purplesabbath9057]

That's because the music actually is compressed during the encoding process. Unless decoded during playback, the signal will have a poor dynamic range. However, the dynamic range is restored when decoded and the end result is a recording with approximately 15 dB decrease in noise.

[@kennethbouchard8643]

That's because it is compressed during playback when in use. Many turn off Dolby NR B type because it only makes the high end boost up some. With cassette limited to only about 15khz, tape is already below your hearing range.

[@noop9k]

Yeah, before this technology was used for evil.

[@unfa00]

I dare to say that loudness war sounds like noise reduction artifacts, lol!

[@RaderizDorret]

I don't know. Sounds like that Dolby C without the right playback equipment could go well in a cyberpunk setting. I kinda dig it.

[@fsfs555]

Dolby B was essentially the best for transportable recordings, as you noted: they sound pretty decent when played back with proper Dolby B, but they didn't sound horrible if played back on a machine without it, unlike C or dbx. So you could take the same tape to your audiophile friends or play in a cheap stereo at the beach and not be too disappointed either way. Fun facts: in the '70s, there was a short-lived experiment with Dolby FM, where your favorite major radio station broadcasts were encoded by Dolby B to reduce noise. The later Dolby C was essentially two tweaked Dolby B encoders run in series. dbx (stylized in all lower caps) was also interesting. Matsushita was a huge proponent of the dbx system which explains why most dbx chips have Matsushita logos on them. However, due to its poor sound on incompatible equipment, in addition to a "breathing" sound sometimes associated with dbx recordings, dbx didn't find a ton of consumer use, even with the introduction of (ultimately short-lived) dbx disc-encoded vinyl records. It was common on professional equipment though, and did get a major win in the USA: a flavor of dbx NR was used for sound in the MTS broadcast system (and most chips implementing it were provided by - guess who - Matsushita).

[@stan.rarick8556]

Boy, now I feel OLD! I used cassettes before Dolby......

[@BrasilGT]

You really deserve more views, your content is great!

[@CaptainCocaine]

Can you do a video on the "Loud" or "Loudness" button on old car stereos? I always wondered why my Dad's old Dodge Duster (complete POS) had one.

[@taakelyset]

This option compensates the loss of the bass when in low volume.

[@CharlieRAnimaMX]

It is not very complicated, it is practically only a band equalizer which increases the gain of the low frequencies. to compensate for its lack in radio transmissions and metallic tapes or when these have a very low volume. -It's kind of like when you wear headphones. You need to turn up the volume to a certain level to pick up the bass, but the rest is perhaps already very loud. the Loud Function, only does that same volume increase to the bass but maintains the rest. It is not so common anymore, but at the time it was quite common to see this function also in mini-components and turntables from Panasonic and Fisher Audio. -Currently it is still used in sony equipment, with the name GROOVE. which generates the same effect but adds a plus by emphasizing the mid frequencies in vocals and string instruments By the way, it is curious how warm the old car stereos of the 70-80's sound. It's probably because the car is a closed room and it resonates better, But overall Those Quadraphonic Arrays, Front Stereo and Rear Hi-fi. They really give a deep vibe, especially with sad songs. -Something that has really been lost in many new cars. (there are some that really sound cheap)

[@Roadhardd]

It boosted the low and high frequencies so you could hear more than just the mids at lower volume.

[@tapemaster8252]

Great video,this is why I always say you need an EQ with any tape deck,it will boost the input sensitivity, you shape the sound for improved output(providing that your line source is matched to the EQ)makes for a very enjoyable tape experience.

[@pftyea]

I pressed "like" at 3:30 ;)

[@Tjousk]

Indeed.

[@misterhat5823]

There's too much missing and not quite right to press "like" on this one.

[@weckar]

@@misterhat5823 That's because this was recorded in Dolby-C. You're just not compatible.

[@hughjass4838]

Clever people with their technology and stuff.

[@InterCity134]

Like the phono RIAA companding.

[@phrtao]

Yes it is - so hardly a new idea was it ?

[@misterhat5823]

No. Phono uses strictly equalization. Implementing a voltage controlled amplifier (needed for companding) would have cost more than the average home eighty years ago.

[@kennethbouchard8643]

No RIAA is not companding or compressing. RIAA is a standard by which the recording is held to. It is a Curve. It stands for Recording Industry Association of America. In Europe and other countries, use different standards. RIAA is just a standard, it is not a process. Dolby of any type is a process. It alters the sound of the recording to achieve higher fidelity. Its application can be applied to ANY analog audio source. Be it vinyl, tape, wire, live, wax, or beam of light movie film and records. Yes there was a beam of light record player once upon a time.

[@sdparksMS3]

When I was a teenager I could have sworn that I couldn't tell a difference between the dolby button and simply turning down the treble. I was right! Partially at least. Now I know the other half of the story. Thank you!

[@nougatbitz]

0:42 it sais: Say „Their first product one more time, I dare you“

[@lancairw867]

nougatbitz Look at the big brain on Noug! 😄

[@tomtalk24]

Thank goodness for KZbin slow playback mode lol

[@wisteela]

Excellent demonstrations. On my old non-Dolby system I adjust the last two graphic equaliser sliders: 1 notch down, 2 notches down.

[@daveThbfusion]

There is a serious lack of a proper 21st century audiophile tapedeck, for digital archiving, that can playback all the different tape types (proper bias adjustments), let alone Dolby Noise Reduction, so that people can simply enjoy (and preserve) their old cassette tape collections. Play tape one more time, and then have it saved on a thumb drive, on a hard drive, in your iTunes, or saved in a cloud account.

[@KaitouKaiju]

Such a product is pretty much doomed to fail in a consumer market

[@MrocznyTechnik]

You don't need to adjust bias for playback. The real pain in the neck is tape azimuth. I'm digitalizing on a separated deck, specially "sacrificed' to this purpose. I just put the tape I intend to digitalise and tune head azimuth for maximum treble "brightness". Of course I tune on stereo channels mixed into mono, the this 'golden point' of good azimuth is easier to find.

[@xapplimatic]

Look for the single tape Sony recording units that look like VCR decks. The ones with Dolby B and C are quite good (even the cheapest ones) and they automatically sense metal or chromium and adjust accordingly. Sony used to be the sheet when it came to audio gear. They wee tops. The 1990s saw the end of the Sony Audiophile and Videophile era I think. Their gear from the 90s was till built like tanks. My Sony deck still works perfectly despite years of no use at all. Clean the heads once, demagnetize once and good to go! I miss the ease of recording to tapes, but I don't miss the bulk, the clunkiness,, the hassles of cleaning and demagnatizing , the mismatch in noise technologies.. They were odd times the advent or CDs and the decline of analog audio.. The really odd thing I that we are STILL using analog audio in cars and building when it comes to FM radio. WHY???? Radio should have gone all digital when TV did. It's the last bastion hold-out for analog audio…and no clear compelling government push to end analog radio and begin an age of all HD (digital) Radio is in motion. Heck, if Obama an the FCC hadn't made a mandate, we'd all still be stuck with fuzzy picture broadcast TVs and non-HD digital cable systems. Sometimes bullying the market with "big government" is a really positive thing that gets necessary change to happen because it won't happen on its own without that "or else" punishment factor for not getting with the progam.

[@johnballantyne3458]

Unfortunately, Dolby no longer licenses their NR technology for cassette decks, so even when TASCAM/Teac came out with a new professional cassette deck last year, it didn’t have Dolby. It had a generic noise reduction system that “roughly mimics” Dolby B. But a new cassette deck that actually has Dolby B, C, or S is not going to happen. :(

[@AnonymousFreakYT]

Been a subscriber for a few years now, somehow missed this older video! Excellent primer on Dolby NR! Also, excellent Pebble you've got there! (RIP Pebble.)

[@swordmonkey6635]

"It was recorded in Doubly" ~ Spinal Tap

[@anonUK]

You can't record heavy metal in Dubly! It just doesn't go up to 11.

[@atrafana]

Excellent lecture on Dolby! Clarified all the question I had.

[@AnthonyMaw]

the explanation is not quite accurate. Dolby NR works by dynamically boosting the high frequencies during recording but the amount of boost depends on how loud those existing high frequencies are. If boosted too much they would saturate the tape's ability to record the highs. During playback the amount of high frequency range reduction also depended on amplitude so that the softest sounds received the most downward equalization. The Dolby logo on the meter indicates the sound level at which the Dolby chips is neutral and neither boosts nor reduces the high frequency band. The accuracy of the sound depends on the sensitivity of the tape and many advanced cassette decks offered Dolby level calibration during recording, along with bias and equalization trim.

[@alexatkin]

Indeed, when he said "I don't sound any different" I was like "umm yeah you do, the higher frequencies are clearly attenuated". Because obviously if the recording wasn't designed for dolby then enabling the function on playback will do exactly that.

[@Balikon]

It was Dolby C that worked dynamically, Dolby B did not. The result was that I always preferred recording with Dolby B although my tapedeck was also featuring Dolby C. But neither my personal nor my car stereo had Dolby at all, so recordings with Dolby C were unbearable to hear due to the dynamic mode of operation.

[@Shamino0]

@@BalikonDolby C sounds great when you have a compatible player. But as you point out, it was never popular on cheap equipment (or on car stereos), and it's unlistenable without the decoder. Which is a real shame, because Dolby C on good quality metal tape sounds almost as good as digital and better than MP3 compressed digital audio.

[@Ty4ons]

@@Shamino0 Dolby C to my knowledge was really picky and required a high quality deck, ideally the same one that made the recording, so most consumer decks, car stereos and portable players weren't good enough. I think that was what ultimately killed it from getting widespread adoption as you didn't need a lot of variance in tape alignment for it to sound really bad. Lower quality players are also paradoxically those that need noise reduction the most haha

[@videodistro]

Yes. Exactly right. He missed the mark on this video.

[@THTSound]

finnaly, thank you so much! after so many years i finally understand how it works, very interesting and clever

[@jeffstephens1049]

It's sad tape is getting thrown away at GoodWill and the Salvation Army. Keep your tapes!

[@mephitusincognito7918]

CD was invented in the early 80s ... CDR in early 90s... no need for tapes...

@@mephitusincognito7918 There's even less need for CD and CD-R now as there is digital recording just every bit as soulless as CD-R, but without the shitty plastic discs.

[@mephitusincognito7918]

@Wandy Wexler Weslon vinyl is a novelty to me at best... the *"snap crackle pop"* of rice crispies that wasnt in the master recording destroy my enjoyment of the music.. less so for this hiss of tape which is why i used tape till i got a cd player.. and ultimately cd burner... digital download is the way to go now granted.. as long as its a lossless format... ...btw vinyl mixes now are simply the same mix for CD/digital... studios use digital recording so you arent getting the 'analog' of days past with new vinyl.... hence; novelty...

[@OfficialSERFATRON]

Not anymore, 6W is one of those responsible why goodwill stopped doing that in LA county, follow 6wrecords on instagram. He is bringing tape back

[@keiyakins]

@Wandy Wexler Weslon Only for non band limited signals. And given that our ears, in effect, do band limiting, we can limit it to a bit wider than what we can hear and get effectively perfect reproduction. There's some noise from the sample depth, but that is equivalent to (and sounds the same as!) tape hiss, and we can control how prominent it is by increasing or decreasing the depth.

[@BertGrink]

Another well-researched, well-written, and well-presented video about audio tech.

[@Mck0948]

Dolby C messes up the stereo image in my opinion even on a Nakamichi deck with metal tape. Dolby B seems fine though!

[@TimJoseph08031990]

I was born in 1990, and in factory car cassette decks, it says Dolby B NR on almost every tape door or on the audio unit itself. For instance when I was a kid, when my dad had the 1997 Nissan Quest with the factory cassette player, there is a sound difference when the Dolby button was pressed and illuminated, while the tape played. But when he had the 2001 Honda CR-V Special Edition, I didn't notice much of a difference during tape playback with or without the Dolby B NR.

[@odouls779]

Audio engineers spent great work making sound pleasant to the ears of listeners. Those were the days of discriminating audio fanatics. Today people do not care about sound quality. They are happy with squeaky tiny speakers and boomy loud woofers.

[@jamesisaac7684]

@@dgpsf I think you forgot to add two 0s on the right side.

[@stan.rarick8556]

Oh for the days of HiFi and good stereo systems.

[@thedissownanceyouth]

But didn't people back in the 80's and 90's listen on crappy headphones and speakers too? I've heard knowledgeable musicians discredit the belief that people generally listen on worse equipment than they people did decades ago, but their evidence was anecdotal.

[@gytux0258]

Your videos are entertaining and informative. You deserve way more views than you get. Good luck!

[@thorbennielsen3845]

A video about HX-Pro?

[@CoTeCiOtm]

HX pro is a different beast altogether. It was not noise reduction per se, if I remember correctly, it dynamically changed the bias of the recording so the tape could record better high frequencies at louder levels, thus letting you record at higher volume without distorting the tape and increase the signal to noise ratio. More modern and advanced decks had similar sistems that recorded tones to the tape and analyze them to get the best performance for that particular tape, some others had a semi automatic adjustment, specially three headed decks. HX pro tapes didn't need to be decoded, as the process didn't change the resulting signal.

[@therackstar]

CoTeCiOtm A great example of this is the Denon DRS-610

[@philliberatore4265]

Very interesting, thank you. I had a ton of cassettes back in the day and always thought the Dolby button was kind of magic. I never really understood how it worked. I'm surprised it was that simple.

[@KyrstOak]

5:50 Creepy music. O_o Very weird. 6:19 Even _more_ creepy! 😨

[@mBUSHattack]

Yeah, it was super atonal, a super bizarre choice lol

[@RaderizDorret]

@@mBUSHattack I kinda dig the music sample starting at 6:19. Has a nice cyberpunk sound for my ears.

[@henrikpetersson3463]

Noise reduction is still used a lot, but mostly in the recording and post processing phase. It's not something that consumers will need to worry about however, so I get your point. Excellent video none the less!

[@melvinch]

Why wasn't Dolby HX mentioned ?

[@AAAZ2A]

Because it's not really a noise-reduction thingy :)

[@maxmace111]

Right. HX is not noise reduction, it's "headroom expansion", meaning you can record at higher (louder) levels without distortion. It's used for recording only, i.e. HX is performed at the time the audio signal is recorded onto the tape. It doesn't need to be decoded at playback time like Dolby NR.

[@davidwillmore]

Melvin Chong I had the same thought. I was hoping for some discussion of bias frequency and how companded recordings had more high frequency signal so that it effected the amount of bias needed for proper recording.

[@ErdrickHero]

It's not often a channel gets my subscription unless I know the person (or people) behind it. Good job!

[@granderondeproductions3286]

Say their first product one more time, I dare ya. Had to slow it down 0.011x to see it. lol one frame only.

[@MELOD]

I didn't need to slow down at all, just tap spacebar a few times :D

[@LordSandwichII]

I managed to pause it just on the right bit! :D

[@dannosaur7]

There's a frame skipper plugin for Chrome that allows you to use the comma and period keys to skip back and forward one frame at a time... much easier!

[@StephandJoshMartin]

Good ol' days

[@Cygnus0lor]

Just use bigger than and lesser than signs

[@MattHobbie]

Thank you for explaintion! I never quite understood HOW Dolby NR worked. I remember back in junior high bragging to my buddies about how my new radical boombox had Dolby on it, but being disappointed when I activated it and I could hear the treble sounds get quieter. I thought it was because the system was flawed. Thanks to your video, I now understand the end game. I also remember that I didn't exactly have the best set of speakers, either. LOL.

[@vladratcu]

I don't think the hiss noise is generated from the tape. I think the hiss and noise is generated by the tape head. You can check this if you start playing the deck without any tape inside. You will still hear the noise, even though there is no tape inside. Please let me know what you think. Cheers, Vlad

[@videodistro]

No. While the electronics in the player generate some noise, called heat noise, it's the oxide moving actoss the head that creates most of the noise. If that were not so, the noise reduction schemes would have absolutely zero effect.

[@michaelbeckerman7532]

@@videodistro What is "heat noise" and what causes it? Why does the oxide moving across the head create noise?

[@mrlordclaude]

Great video. Takes me back to the 80s/90s. I always likes Dolby (b) off, I preferred the additional treble. Not knowing how it worked, I believed they they just tried to "lop-off" the offending frequency. When Dolby c came out, I was a changed man. My recordings on my good old JVC tape deck of a CD, was almost indistinguishable from the CD. The deck was eventually stolen, and along with it my tie to magnetic tape. I listen intently to these videos, and they answer questions I never thought to ask. The most bewildering thing is though, how can anyone click on "not like" on these videos. Keep up the good work... 😀

[@HoudiniFontmeister]

You got me laughing with all the sibilance hahahah

[@Robzter117]

I recently came across your channel and it's now one of my favourites! Your videos are all amazing, thank you for doing what you do :) Is there any chance you could do a follow up to this video explaining the specifics of how each generation of Dolby noise reduction improved on the last? Your explanation in this video of how noise reduction works was excellent, but it's left me wondering how they improved on it.

[@jasonschmitz1055]

i dont know, maybe its just my dyslexic ass mixing the sentences together but a little more than a split second gap between sentences would be nice. its all good tho, if quick pacing is your thing, keep doing what your doing and ill keep watching regardless.

[@elephystry]

Jason Schmitz try watching crash course world history

[@tag1462]

Thank you. I have always wondered how that worked. I do remember that famous arc setting with the levers do get the best sound.

[@novatolock]

you could clean the power button on the technics cassete player...

[@gavincurtis]

That's load bearing dirt. Can't do that.

[@bld86]

such well produced , to the point videos . Keep it up , These are great .

[@MrXavierRose]

My mother and myself never used DNR because it sounded dull. Didn't mind the hiss.

[@CanuckGod]

Yeah, it was pretty iffy, as you said, it did tend to drown out stuff more than was satisfactory.

[@jeremygeeraerts5030]

The cassette you showed at the beginning "USA for Africa: We Are The World", I remember it, I used to have one. God that brings back memories.

[@richard1113]

Always left Dolby and Tape Bias OFF back in the day to keep them from messing with the real sound. I don't care if there is a slight, very unnoticeable hiss in the background as long as my highs are not clipped! Dolby was the devil as far as I was concerned. And as far a tape media was concerned, I only used Metal (once it was available). The tapes cost more than the LP I was recording! LOL.

[@videodistro]

Um, you can't torn bias "off". Bias is a very high frequency tone (above hearing) that is recorded on tape same time the intended audio is recorded. The tape has to have bias to record properly. All you could do was adjust the level of bias based on tape type. Our pro studio decks would let us change bias to any level. Most specs called for over biasing by 3 dB which would give a bit more head room but would very slightly dull the recording. We would routinely peak bias and just be very careful with levels. As important was tape head alignment, but that's another story for another day.

[@michaelbeckerman7532]

@@videodistro Why does a tape have to have bias to record properly? What purpose does bias serve in the recording process? How is bias measure and what are the options for different types of bias? What are the pros and cons of each of the different types of bias?

[@Unreissued]

one of the best channels on youtube

[@JoBot__]

0:42 Say "Their First Product" one more time, I dare you

[@bloqk16]

A sub-category with regards to Dolby Noise Reduction, when it came to using blank cassettes for home recording purposes, could be with the "bias" that a given cassette deck were calibrated to when using blank cassettes. I've gone through many cassette decks over the past 40 years, from the first being a Pacific Stereo Trans-Audio deck of 1977, all the way up to DENON decks in the year 2000; where I've learned that to get the best fidelity out of the cassette deck, the user needs to test various blank tape brands to discover which one is best suited for recording/playback. In one example, it astounded me how an Onkyo tape deck sounded lousy with TDK cassettes, but sounded great with Maxell. And, surprise of all surprises (sarcasm), a Sony cassette deck sounded best using blank Sony cassettes. People with lower-priced cassette decks, and a lack of available info, were hindered with getting the best fidelity out of their cassette decks; especially so for those users that were budget-minded and bought whatever blank cassette brand that was discounted on-sale. Some of the higher-end cassette deck manufacturers compensated for the fickleness of the blank tape brands with including a knob dial for adjusting tape "Bias." The Bias knob was generally found on three-headed cassette decks; where in the "record mode," the adjustment knob was used.