Dolby Noise Reduction - Did it ever really work right?

I love cassette tapes, but I've always been disappointed in the sound quality when activating Dolby Noise Reduction. Even though this deprecated, no-longer-licensed technology once dominated tape decks around the world, it still makes me ask the question... did it ever really work right?
0:00 Intro
0:35 How Does Dolby Noise Reduction Work?
1:39 Dolby on Prerecorded Tapes of Yesteryear
2:35 Recording Directly Using Pure Digital With Dolby Noise Reduction
4:02 Results Of My Own Recordings
6:00 What Do New Tapes Sound Like Today Without Dolby?
6:56 Olivia Rodrigo - Pre-recorded Tape from the Record Company
7:24 Olivia Rodrigo - Recording Directly From A Digital Source
8:01 Verdict - Did Dolby Noise Reduction Ever Really Work Right?

[@sneskid78]

One issue with cassette is that the head azimuth very rarely matched 100% between two decks (unless you realigned them yourself like I did) so there’s a very good chance that the head alignment on your tape deck does not match what’s on your prerecorded cassette. Since Dolby NR is a compander based system, its performance is dramatically degraded if the alignment is even just a tad off.

[@blade3120]

disapointing for dolby? ARE YOU SERIOUS? LISEN DOLBY NR ACTIVATE ONLY TO RECORD WITH MICROPHONES VOICE NOT FM BRODCAST SECOND BUY VERY BAD CASETTES! BUY BETTER CASETTE EXPECULY CHROME BIAS OR NORMAL CASETTES TO SUPPORT HIGH OUTPUT AND CRISTAL GAMMA! AVOID CASETTES TYPE 0! IS NOT CASETTE! THE TYPE 0 CASETTE IT IS FRAUD CASETTE! EXELLENT CASETTE ALL THE BIAS IS TDK! SECOND MAXELL LAST SONY!

[@sneskid78]

@PWS Productions Dirt, and also tape/head wear. With due respect, I can get azimuth pretty spot-on by ear. I pretty much have to when I’m digitizing old tapes and I want to get as much off of them as I can.

[@sneskid78]

@PWS Productions Back when I used to record onto cassettes for listening on my Walkman or in the car, etc., I got pretty good at adjusting by ear. I’d record something with a good amount of highs, and then use that to re-align other decks to it because I wanted to be able to get the best I could from Dolby NR. It actually worked quite well. Summing the outputs to mono really exposes azimuth error, in that even the slightest bit will cause very audible phase cancellation. I still use use that method today when I’m digitizing old cassettes and I want to get as much off them as I can.

[@westelaudio943]

@PWS Productions The good thing about Dolby-B, as opposed to C, Hi-Com etc. is it will still sound alright even with a slightly misadjusted or ground down head, adjusting by ear will be fine. If Dolby B doesn't work it's either user error, or the adjustment is too far off, and when you're unlucky, the head is too far gone.

[@tacofortgens3471]

never gad issues with azimuth, just dirt, and rarely magnitized. people messing with heads not knowi g what they are doing.

[@ZacabebOTG]

As far as I know, the Dolby level marking on the VU meter is just a reference for calibration to make the expansion match the compression and reduce pumping and breathing. It does not mean it's the peak recording level. Also of note is that NAD and Yamaha introduced a feature named Play Trim, which EQ'd the sound before Dolby decoding to compensate for errors with cassettes recorded on a different deck.

[@rocker11281]

Wanted to tell the same. In no way the Dolby symbol is kind of a level limit. I made some great and loud recordings with Dolby S on my Sony deck on some really hissy Type I tapes.

[@MikeDS49]

1:47, I believe almost all prerecorded cassettes after the mid 70s until rather recently had B NR. It was indicated by the double D logo. It didn't have to explicitly say "B NR". I am guessing it was only written once C was available. There are Dolby S NR cassettes, but they're rare. Some Canadian (Cinram) pre-recorded tapes rival homemade type Is in quality. There are also CrO2 tapes from CBS recorded with type II bias and are to be played back as a type I. Some consider these exceptional. You're right, with modern formulations, noise reduction is less of an issue, or almost non-existent. But you pay through the nose for type II or IV tapes. I have a couple bricks of new old stock "super ferric" ferric cobalt tapes that take tons of signal (Memorex dB C60s, < $1 each), have very good frequency response, but are hissy. C NR virtually eliminates hiss. Being older, my hearing falls off above 13 kHz. To me, the HF sound quality is almost indistinguishable from off, while still holding a signal 3+ dB above the double D marks.

[@dobermanguy9437]

A lot of people did not understand this back in the day example when you record in Dolby C You playback in Dolby C the same with Dolby B people basically just turned Dolby on and off and didn't realize how the proper way to use it

[@johnviera3884]

that’s exactly why it’s not good. you don’t design a confusing consumer product. and then blame it on the consumer

[@sneskid78]

Well, that’s a case of RTFM, which I admit not many do lol That said, TV broadcasters here even got it wrong quite often. Either playing something with Dolby on when it wasn’t supposed to be, or playing it without Dolby when it was supposed to be on. I even have a DVD box set of the first season of “Who’s the Boss?” that has that issue! The first episode was definitely transferred with Dolby NR turned on when it wasn’t supposed to be. Because of that it’s hard to hear some of the dialog - the quieter passages are quite muffled, and anything with higher frequencies (such as “S” sounds) have that all too familiar “pumping” effect.

[@olaniyi570]

Prerecorded tapes have always been challenging but with recording and playback on the same deck I've never had any problems with Dolby C which to this day is my favorite system. Incredible reduction in noise and on good decks without any sonic artifacts that I can detect.

[@sguttag]

Dolby NR did work well but, clearly, not for everyone on every deck. I don't know where you got the idea that "Dolby-Level" is the level you are supposed to keep below. That is not the case at all. Dolby Level is the point where Dolby NR stops compressing the recording (or expanding the playback). All signals above Dolby Level are unaltered and should sound identical between no NR and NR. The upper end is determined by your deck and the tape formulation as to when it saturates. Proof of properly calibrated Dolby NR is pretty easy to achieve as one can record something like pink noise and play it back on an RTA and compare with and with NR and then record at differing levels. If the frequency response changes with level, that would indicate mistracking. However, with your set up, part of the problem is likely your recording levels. Most cassette decks can only achieve their wide frequency response down in the -20VU range (check the spec sheets for your deck). If you are recording up in the 0 to +3dB range...odds are, your deck is already killing the HF range some and when you add Dolby NR to the recording, it will exaggerate it. If you drop your recording level a bit, you'll likely get your HF response back and have an even wider frequency response without picking up the noise. Dolby-B is going to get you about 10dB of NR in the critical frequencies where hiss and such will be perceived. Dolby C will get you closer to 15-16dB. So, based on where your deck can record the higher frequencies, you can target your recording level and then use NR, properly, to keep tape noise in check. Dolby S will go yet further to allow one to optimize the recording level and dynamics of one's deck. Sony is a bit closed on their published specifications but for Type IV (Metal, they show that the frequency response is 20Hz-21KHz but it reduces to 20-16KHz at 0VU and you were 3dB above that and using Type 2 tape, it would likely be down at 13KHz or so by 3dB at 0VU and even more so at +3VU. It is one thing to use no NR and to record hot to keep the tape hiss down but you will do so at the expense of widest frequency response (not many people can hear up to 20KHz and not much is recorded up there anyway). But with NR, the goal is not to record as hot as possible but to use the NR to achieve a wider frequency response while keeping the noise floor lower and to strike the balance between the two.

[@marcisberzins]

Hi! It is just not true in general that above the Dolby level any Dolby N.R. do not do anything to the signal, for example, Dolby B do not really touch signals above about minus 10 dB, Dolby C modifies signals at all levels (but differently) etc.

[@andygriffith5160]

I'm definitely in the Dolby-off camp. I like tape hiss because I like the imperfections of the format and the variations between tape formulations. To me, the cassette format is the audio equivalent of Super-8 film. It has its own wonderful character all of its own and trying to clean up the noise, the glitches, the variations in frequency response and the dropouts would be a destructive exercise which would negate the reasons I love cassettes.

[@Seiskid]

Good video. Dolby is very finicky in regards to correct internal deck calibration - something that has drifted on most 30 year old decks. You've calibrated the tape which is good. But if the internal record/play calibration is out (recording hot and playback weak ~ or vice versa) this will still mis-track Dolby. As little as 0.5db mis-calibration will throw Dolby-C off creating an slightly bright or slightly dead recording. Get it right however and it can, and does sounds very good indeed. As others have said the Dolby symbol on the display is a reference level. Despite what you hear on the internet its perfectly fine to record past this point. Dolby-B is turned fully off above the dolby reference point and has no effect good or bad. Likewise Dolby-C turns off except for an added anti saturation filter that reduces high frequency tape distortion at high levels. You mentioned Dolby-S. I can confirm it is good. It makes standard tapes (eg TDK-D) sound like expensive tapes recorded with a well calibrated Dolby-C setup. Almost CD quality. To the ears at least (although test equipment still gives the game away). Dolby-S is a four band system and to minimise mis-tracking it was designed to do as little as possible unless actually needed. In comparison B and C are single and dual band systems respectively. There's one final thing that Dolby has a LOT of trouble with. And that's modern sound cards. Quite a number of them leak ultrasonic noise and that causes severe Dolby mis-tracking during the recording process. If a recording sounds junk from a laptop but great from a cd player this is often the cause.

[@1pdonlon]

I always felt the same with Dolby NR. I would always use it when recording, but never when playing back as it just sounded muffled and dull. 🙂

[@brocksamuels6008]

Try a 3 head with Dolby S and you will change your mind it was the consumer 5 band system from dolby based on Dolby SR it beat out minidisc for sound quality in stereo review shootout in early 90s plus i didnt see you adjust bias or how often are the heads cleaned good video but a few questions about the test keep it up im subbed:)

[@professorvoluck9311]

He did the calibration process correctly which includes adjusting bias and it is a 3 head deck, just no Dolby S.

[@user-Merovingian1980]

sorry but no cassette tape will beat minidisc for sound quality .. DAT maybe but not compact cassette

[@geoffgero6081]

I've always liked noise reduction. Playing tapes that are Dolby encoded without Dolby turned on sounds terrible to me, its almost like turning the treble all the way up

[@albertpintor3522]

That means you have a decent deck or tapes

[@c128stuff]

For type II tapes, not using dolby means you get some 3-5db more headroom during recording. That is also how much you can lower the noise floor by recording louder and compensating for that by loweing playback volume. Dolby B, provided everything is calibrated properly, gets you a better reduction in noise levels, dolby C even more, but is even more sensitive to proper calibration. Proper calibration isn't just about bias/levels/eq, but also about internal playback amplification being set properly, azimuth being correct, etc. Also, using a 3 head deck, and monitoring the recording lets you change the recording level to the point where the 'dullness' goes away. Keep in mind recording levels as indicated on your meter are not exact science, the proper recording level, and how this recording level affects the tonality and linearity and distortion is quite dependent on the actual content. Use indicators on the display as a starting point, but also monitor and adjust to make things sound right. With that, dolby C (and even more so Dolby S) can get you much much better results that you got here.

[@bertheeren7992]

One thing not many people know: Many cassette decks, including high end models, did suffer from wearing erase heads. Teac, Denon, Technics . . The wearing erase heads gives mechanically friction on the tape while playing, causing partial HF erasing on type 1 tapes. Not electrically, but mechanically. Every time you play a type 1, as most pre recordeds, the highs will be erased a little bit, although it settles after a few plays). It can be as bad as 3dB in my measurements. This is one of the biggest reasons so many pre recordeds are sounding muffled today, as nearly ALL 80s decks suffer from this problem and most pre recordeds are type1. Using dolby will exaggerate this problem as it misstracks Nakamichi and later many other brands, got sandust protected erase heads to battle this problem. I found out this a few years ago that, only on type 1 recordings, the highs disappeared after some plays. Putting some clear tape on the erase head fixed it (and still do erasing the tape sufficiently)

[@rustyshackleford8043]

My memory is the tape hiss being much more than in your demo. I also remember other artifacts - which I know now were wow and flutter. I feel the reality was, most of us had very cheap low quality hi-fi's, and the Dolby stuff was meant to mask that.

[@Solitaire001]

My understanding is that Dolby Noise Reduction (DNR) only raises the highs when the volume on the tape is low because that is when you would notice the tape hiss. That could be the reasons that the sound is thrown off when you play the tape back when using DNR because the deck has to correctly determine when the highs should be reduced. When I was using cassette tapes I thought that instead of using DNR I'd use a graphic equalizer to manually raise the frequencies where the tape hiss is, and then manually reduce it by the same amount when playing the tape back. Basically, it would be the same thing that DNR does except it would be on all the time.

[@LostBeetle]

To do a truly good bias calibration record pink noise, listen to the high end comparing to the source. It should sound as close to identical as you can get. Here's my method on two head decks. Digitizing your pink noise recording into audacity you can use the "split to mono" feature on both the source and the recording to compare left and right channels. Also you need to make sure the volume of the recording and source are equal, use the "gain" function to do this. If you do this and the internal record and playback pots are calibrated well enough, you won't lose any high end at all. In fact, you can boost it by under biasing a little if you desire. A bit time consuming, but you'll get a perfect recording using dolby. Now, I see you have a three head deck, so this process could be even more streamlined by just switching between the source and recording while listening to the pink noise. You won't get quite as close as you will by digitizing into audacity and splitting to mono and making sure the volumes are perfectly equal, but it should be adequate. I just have two head decks myself so the first method is what I use. Just using vu meters like you did here will get you close, but tiny adjustments that won't even register on those meters can be made with your ears and pink noise. Do not try white noise, white noise is nothing like music and the only way a cassette can match the source using it is with extreme under biasing. You do not need type 2 or 4 tapes. A decent enough type 1 will work, but it will have a higher noise floor.

[@TechStuff1]

I gotta try this method - thanks for the info!

[@LostBeetle]

​@@TechStuff1 Forgot to put in there. The pink noise can be generated in audacity. Also, instead of comparing the recorded pink noise to an untouched freshly generated pink noise in audacity, it might be better for your source pink noise to instead be coming from the headphone jack or line out on the deck in the process of recording. The generated pink noise is just what you obviously use to make the recording. To me this makes sense as the deck might change it a little bit as it goes through the circuitry, so you might want to match what comes out, not went in... maybe. I can't conclusively say for sure if it makes more sense to use the original untouched pink noise in audacity or after it has gone through the deck and back into audacity as your source as both will give you outstanding results, but I think it makes more sense to use the latter. That and the volumes will be much closer or exact, they might be 1-2 db off, depends on how calibrated the deck is and the tape. Good luck hope it works out for you. Hopefully you can start using dolby for your recordings.

[@MikeDS49]

Another source of noise (not pink though) is to use the static from a tuner. With a digital tuner, it may be harder to find an empty bad, but it's worth a try.

[@tenej6992]

You could have actually put the 3-head system to use to jump between source and the different dolby's... The three heads on there are for a reason you know. Another thing you would have to look for is if the deck is even properly calibrated. Dolby B is quite forgiving to a slightly off azimuth or improper levels on the deck, but Dolby C easily sounds muffled.

[@jaymartinmobile]

Dolby B was a very mild noise reduction designed so that if you played it using non-Dolby equipment all that was needed was to reduce the highs a bit. The biggest problem with Dolby B and C is that they are very dependent on proper calibration of the recording and the average (or really RMS) level had to be at the Dolby zero level to be most effective. Unfortunately most later decks have peak meters not RMS and so your recording levels are too low and the Dolby becomes much less effective. You have to set the recording level so the meters bounce back and forth around the Dolby 0 level to be correct on a peak meter. And as someone else said head azimuth is also critically important. No pre-recorded tape could hope to keep the Dolby calibrations after high-speed duplication at the factory, so it would always muddy the sound to a certain amount if played back under Dolby decoding. Dolby S addressed most of these issues and DBX noise reduction never had them, since instead of a volume-dependent log-scaled reduction it was a straight 2:1 compression. As far as I know though DBX was never used for pre-recorded tapes, since the tapes are totally unplayable without decoding. Dolby was a cheap way to say "we tried to make it better" without it requiring special equipment to play it back. Dolby B was really invented for noise reduction on consumer reel-to-reels back before low noise tapes. Back then you hand-calibrated your Dolby AN-60 (if I remember my model number correctly) compandor unit yourself using test tones and set screw level controls. And then all your levels were set using analog meters which by nature were RMS. I think it was more a part of the culture by the time high-fidelity cassette came around, and consumers wanted what they had on reel-to-reel.

[@DougMcDave]

Cro2 takes some of the hiss out, also. It also boosts the highs. Type II sounds better than type I cassette.

[@kirkmooneyham]

There were Type I tapes that sounded very good, but they were expensive and harder to find. Examples are TDK AR, Maxell XL-I, Sony HF-S. Prices and availability of those now are much worse, of course.

[@linds12341234]

@@kirkmooneyham that's fx. Beats 90% of my type iis. Same deal with the Fuji FR-I Super

[@littledoodle5689]

beautiful video homie, nice information

[@wyattholm5720]

You have only mentioned music. I have talking recordings of my grandfather from the 1960s. The hiss is so bad I can hardly stand to listen to it. I just recently bought a refurbished Teac deck with Dolby nr, the difference is outstanding. It may muffle the sound slightly, but it is much better with nr.

[@nancy4don]

Couple of things. First, turning the record bias up all the way like it appears you did will definitely dull out the high end. To set it correctly, tune an FM tuner in between stations with muting off and let that be the source into your deck. (It's pink noise.) Since it's a 3-head, you can monitor changes off the tape; so adjust the bias while listening to hear the best high frequencies. Switch between source and tape on your cassette deck to check it. Next, always under-record a little bit. If you push the loudest parts up so that the peaks hit or exceed the Double-D logo, you'll possibly saturate the tape, which means a dull high end. Lastly, I don't know if your Sony has it, but many decks from that era had a calibration tone that you could use (I think it was 400Hz) to set the Dolby tracking. If that's available, use it. I think you will notice a significant difference if you do these things.

[@trippmoore]

Actually most prerecorded tapes used dolby nr. Its also less necessary for rock or pop music were the signal is usually above the noise floor thus covering up the hiss. Especially if you record your tapes “hot”, which is much easier to do with better hardware and tape formulations. For styles like Jazz or classical where they have greater dynamic range in the compositions there will be lots quieter passages within a given piece, and for some soft mellow pieces the entirety might be insufficiently loud to cover up the hiss. And these styles were more popular when dobly was developed so it made sense to use it often. One additional point is that dolby B effect is limited so that one can playback a tape recorded with dolby B in a deck that had no dolby circuits (many OEM car stereo decks for example didn’t have dolby because the auto companies would have to pay a licensing fee for each car that had a tape deck with the technology) and it will sound ok and not too weird. Cant do that with C or S, or other NR types like dbx.

[@colloidalsilverwater15ppm88]

On my former deck Pioneer ct 450, both Dolby B and C works extremely well. Especially C ,full of strength and dynamic.

[@andrewdiamond8273]

I also always use Dolby C on my old Dual CC8020. Any sound distortion. Checked by switching from original music signal to the recorded one and back -- no difference. And no hiss.

[@middlesbroughmike1027]

I'm kind of glad that you got the outcome you did as my ears have always favoured recordings without Dolby as I too find them a little flat and muffled. I have x3 decent quality cassette decks and not one of them (to my ears) sounds better with Dolby (even when the deck is used to make the recording and play it back). Thanks for the video.

[@NeedleDropRules]

Great video! I myself have always preferred listening to my cassettes with Dolby off. Yes, the hiss is there, but I too always felt that the high ends of the music suffered when using Dolby noise reduction. I've had a lot of different decks over my lifetime. Some cheap, some expensive. And I always seem to have about the same results. I did learn at a young age that the quality of the tape did make a difference to my ears. Maybe I wasn't doing something right? Possibly yes. Did I just get used to the sound of no Dolby on since I started listening so long ago in the early 80's? Probably. I suppose I'm just used to it, like a pop or crack in a record. Either way, I still enjoy them!

[@ChopstickSamurai]

In my experience with Dolby it really depended on the album when it came to making a tape sound better. But imo it was a rarity when it actually did so I just kept it turned off. :)

[@terryhall3960]

Dolby NR is one of those things that works fine in the lab (or a professional recording studio) where everything is all tightly aligned and calibrated up the wazoo. But when subjected to the variations of mass production and the cheaply-made, worn-out, dirty, misaligned tape deck that Joe Blow owns in the real world, it doesn't work so well. Plus, of course, there are tons of cheap tape players like ghetto blasters, Walkmen, car stereos, etc. that never had fancy stuff like Dolby or chrome tape options on them anyway. If you're selling pre-recorded tapes, you have to make sure that those tapes sound at least "okay" on those units as well as the Nakamichi Dragons. Dolby B sounds at least passable on those cheapo decks, while as Dolby C or DBX sounds just plain weird when played back on equipment without those options. So at the end of the day, it's a compromise between quality and making a product that's cheap enough and compatible enough for the great unwashed masses with junky equipment who made up the vast bulk of cassette buyers.

[@bertheeren7992]

Dolby works very good in my experience when the calibration is done very carefully, including the internal meter calibration that can shift over the time. Also some tapes didnt had a very flat frequency response and worked less with dolby.

[@Kylefassbinderful]

First of all I was never annoyed by tape hiss all that much. I would just record hot and that was enough for my ears. I mean after all we're still talking about a limited medium. Dolby B was 'ok' in some settings but if you had a decent if not great deck with HX Pro that was really you needed. I also thought pre recorded albums with HX Pro sounded great. But Dolby C was terrible. Dolby S was good but it gets overhyped.

[@scottstrang1583]

It wasn’t bad as long as the alignment was right, heads clean and good tape was used. When but came to Dolby C it rarely was acceptable unless played back on the same deck that recorded it.

[@kirkmooneyham]

The best bet is to have a deck that can calibrate for the individual tape (either manual or auto-calibrate), and then record the tape as "hot" (highest input level) that you can without causing distortion. The quality is much higher and the hiss will only really be noticeable during very quiet passages or in between tracks. So, yes, I agree with the channel.

[@mariovsquez]

Where'd you get that lamp from? Looks awesome

[@sandyclaws2936]

I never bother with B or C, but I will use S sometimes for cassettes. On my reel to reel I have a separate DBX encoder / decoder that works wonders!

[@Mr_Meowingtons]

yeah i have a DBX 224 unit and it smokes B and C

[@robicelus]

I have the same deck and equalizer (i have a playback test in my video). great old tech that sounds wonderful even today.

[@graemeking7336]

Ive never been a fan of Dolby nr, but Thomas Dolby's 'The Flat Earth' is a brilliant album

[@mikevincent6332]

I never liked it, I never used it, it just made everything sound muffled as you say. I like hearing the highs along with the hiss. Nice channel by the way just found you

[@petercreed2539]

My Nakamichi always plays back pre-recorded with Dolby very well, pre-recorded tapes mainly used Dolby B

[@rogerking7258]

You've got a Naka! Lucky sod.

[@joelcarson4602]

Also, when was the last time you demagnetized the tape heads?

[@KR1275]

The Dolby logo on the VU meters is for calibration (mostly for tuners), it's not the recording level limit. And if you switch on Dolby, you have to calibrate the tape again.

[@JRob1125]

That pre-recorded tape actually sounds decent. Most modern ones are about as good as the cheapest tape you could buy at K-Mart back in day. Side note....pre-recorded tapes with Dolby B started sounding really good in the late 90s....but it was FAR too late by then

[@cookiebinary]

Couldn't the reason for the greater noise on the prerecorded tape be due to the fact that it was Type I versus the new tape Type II (position high)?

[@JRob1125]

That's exactly the reason. I don't think Dolby NR was really necessary for Type II and especially Type IV

[@1ring2rule3pigs]

They still sell tapes?? I didn't know. Cool.

[@timleelim9930]

Nice to see some things don't change ie prerecorded tapes suck compared to a home taped one today as it did yesteryear. "Home Taping is Killing Music" proved to be as true as "Perfect Sound Forever".

[@robetclo2516]

There is Dolby S also wich arrived too late but I recorded tape II and IV tapes with it myself and a little difference between the CD and the tape a little lost in high only audible when you make a direct A B comparaison otherewise it sonds great with Dolby S. But a tape must be recorded with it and playback with it as it is a two way process. Yes I prefer recording with Dolby as the hiss of the tape is never part of the music therefore must be eliminated.

[@AudioFileZ]

Dolby B, and later C, became ubiquitous. You'd see it on Walkmans and all manner of budget decks. Now your deck isn't a budget deck, but it does come off an assembly line at a plant where the watchword is to ship, ship, ship. I have a 3-head Sony deck myself not too different than yours except mine had the newer Dolby S included. I noticed my Sony must be somewhat not aligned to it's best as my home recorded tapes with B & C sounded crisper on my Aiwa and JVC 3-head decks. Either these are off at exactly the same amount or the Sony is? I'll guess since two of three sound more crisp in the highs with Dolby B or C that the heads must be more to spec as far as alignment goes. The best Nakamichi decks had very rigid head stacks whose adjustment mechanics were meant to be tweaked, even automatically. They didn't wear out with tweaking as it was a factor built in to their design. Most other Japanese decks eschewed easy to adjust head alignment screws, even putting a dab of locktite on them so they would never move. Let's say these screws are loosened and moved. The stamped metal chassis for the heads being less rigid and the cheap screws add up to drift, sometimes sooner than later even after a righteous alignment. I feel your Dolby is better off solution in the light of these things. My 2004 Audi S4 factory cassette has Dolby B and it sounds just like a cloth was dampening the highs. Head cleaning and demagnetizing makes no difference. It's because it's a cheap auto-reversing mechanism with terrible alignment. I'll quit, but I'll say Dolby B and C is not as inherently flawed as the high-speed pre-recorded tapes or the poorly aligned tape heads. It can be implemented and played back properly but so few decks actually do this.

[@amajtheory]

It seems Dolby noise reduction is better for studio multi-tracking where you record each individual instrument. Each track would be quieter because there was only one instrument, so the dynamics were on and off, loud or quiet. As suppose to a collection of instruments played together where the dynamics are all over the place, making it difficult to reduce noise.

[@stevenichols5708]

I always calibrate my deck with the desired Dolby level switched on before calibrating

[@colloidalsilverwater15ppm88]

And, you can freely forget Dolby, by using Compander. It is dbx, essentially. I made one for myself, 30 years ago, and it works well till today. Clean, adjusted, demagnetized head is a must. Also, you should adjust head for prerecorded tapes. Then you can test dolby b on it.

[@jackcohen3999]

I think Dolby noise reduction make cassette tapes that you record yourself sound a lot better. Cassette Tapes sound muddy compared to the source without dolby noise reduction. My deck is a Technics RM-7 from the late 1970's or early 1980's with only Dolby b noise reduction.

[@schlechtj1]

You CAN NOT switch Willy nilly between noise reduction types like your doing in your test. Noise reduction is an encode-decode process and you need to encode say for instance type b when you record. Then, you should use the same type (in this case b) when you play it back. You can KIND OF encode b and then not decode it. That's because it's mild but if you encode in type c which is much stronger, then you should play it back with type c engaged.

[@revalid6824]

Ive been confused about dolby. I recently recorded a bunch of tapes with dolby but noticed the muffling when playing them back with Dolby c turned on. I thought my decks/boomboxes weren't correctly calibrated but it seems its just the norm & ill probably be better off playing my tapes with Dolby turned off.

[@westelaudio943]

It is misadjusted. It is not normal. Don't use Dolby C then, Dolby B works better with non-calibrated or worn heads.

[@Mr_Meowingtons]

Dolby Noise Reduction B and C never sounded good to me.. i got a DBX 224 unit and i was blown away it sounds good.

[@ThePierre61]

your deck have an issue. Mine (790ES) don't show any of these problems...

[@sebastianp.48]

so you guys are aware of the fact that the tape needs to be recorded using the exact type of dolby nr that you're using to play it back?

[@sebastianp.48]

i'm a long term user of a yamaha KX-670 kassette deck and honetsly, i can't believe how someone can state dolby NR doesn't do anything good.

[@sebastianp.48]

you're recording without dolby, yet you're trying not to exceed the dolby logo on the meters?

[@velisusi1]

Yes, I have a same opinion 👍

[@serratusx]

This matches with my experience of Dolby, I almost never used it, especially on type 1 ferric tapes which already sounded quite muffled. I would sometimes use it for playback of chrome tapes which had a much brighter sound and could cut through the muffled effect, but on quiet passages you would still get reverb tails cut off. On my Walkman I was forever switching Dolby on and off depending on the recorded material and type of cassette. There was never one universal setting which works on all music

[@albertpintor3522]

Dolby is extremely hit or miss even if I do have my pioneer 603rs set and cleaned right that I never use it but I do use the flex feature which improves the highs especially on bad tapes

[@floppij5572]

Your supposed to keep the levels above the Dolby icon otherwise yeah it'll sound muddy

[@kennynvake4hve584]

I record in dolby B and listen with no dolby. I like to hear the high's...and hiss is ok with me...

[@q95oldies57]

My experience with dolby, it kills the highs!

[@rlowle1228]

Guess I was ahead of my time. My rule of thumb is "never buy recorded tapes". I ALWAYS recorded my own tapes from vinyl.

[@JamesT65]

I am glad it wasn't just me, I hated it so much I just never used it. HX Pro on the other hand was a far better approach and is an amazing tech.

[@KR1275]

Indeed! The higt end decks from the 90's are the ones to get! A Sony TC-K950ES makes better recordings than a Nakamich CR-9 or Dragon. Mostly because of HX Pro and a higher recording bias frequency (and other high quality parts of course).

[@foggybrain]

The problem you have with pre recorded cassettes is azmith alignment not dolby, this is why your recordings sound better

[@vals8062]

I feel that dbx nr is best by far, no hiss, sounds just like the source you should buy a unit with dbx and try it, it but must be recorded hot read the manuel on unit for peak setting.

[@TechStuff1]

It's funny, out of all the equipment I've owned over the years, I never owned anything with dbx. I had a dbx compression unit, but not anything with noise reduction.

[@barcrocker4802]

@@TechStuff1 dbx NR definitely works well, but sounds awful in decks that don't support dbx. Great video, as I too didn't care for the high frequency roll off of Dolby.

[@rodrigobelinchon2982]

yep, dbx definetely works very well

[@idontsmile666]

The way I always use the dolby nr is to record with it on and play with it off, the hiss is still there but sounds alot better.

[@TechStuff1]

Interesting...I think the highs might be too harsh for my liking.

[@funkmon]

@@TechStuff1 same. There was a DNR button on my old Chevrolet that sounded good so I don't know what that shit was

[@albertocabezas282]

But you add an artificial treble boost that makes the tape sounding quite shrill. I used to like my tapes that way until I was adquiring more experience in audio.

[@dobermanguy9437]

I was always told if you record with it on you have to play the tape back with it on

[@65CJ5]

Back in the day, I recorded with Dolby B on, and played back with it off as well. Most of my tapes were mix tapes I played in the car, and the extra high end was helpful there. I have a new (to me) 3 head deck I'm trying to get repaired. Once I get that back I'll try experimenting with NR and tape types and see what I find with that.

[@John.Doe.2025]

Whooow, 01:00, reeeeely? Maan, you didn't got what the Dolby NR is. It's about "amplitude", not the frequency. There is no technical way to scale frequency in its domain, as you showed. You can translate it into another band or change it amplitude.

[@voidFutureVector]

Should have fought the copyright claims. This video falls under fair use.

[@ingekvam324]

The consumer market Dolby systems was bad. The professional type A and SR worked very well. Cassette decks with DBX was way better than the Dolby B/C ones. They even experimented with DBX coded vinyl records, which sounded awesome. They had very good dynamic range, and no noise or crackle. Too bad they didn't make it to the market, because then CD's came out.

[@SPKMMTV]

You have to record at Dolby B and hear at Dolby B. Yhe same goes with Dolby C. Off course you have to record from a CD or a hi quality Turntable with crystal clear original recordings (no mp3 sources/. Commercial tapes are horrible.

[@guessundheit6494]

The actual verdict, not his: tapes are best played back with the same noise reduction they were recorded at. If it's recorded with dolby, use the same dolby. If it's recorded without, play it without.

[@rogerking7258]

There's no such thing as a quality cassette deck without Dolby. Tape noise will always be an issue without it and in cassette's heyday only the cheapest and nastiest equipment would have omitted it (one of only a few exceptions to this being JVC's use of SANRS which was really just a way of circumventing licence payments to Dolby). All modern decks use essentially the same transport mechanism that is utter pants whatever their price, and they also have no Dolby because it isn't licenced anymore. There are a few high quality looking decks available that are reminiscent of equipment from the 1990s, but this is sadly just a facade. Did you actually switch Dolby B and C on for the recording as well as the playback? There's no sign that you did but you may just have omitted it from the video. Dolby is a two way process requiring to be used during both recording and playback. And you certainly can't switch between B and C when playing back (like you were doing) the same recording unless you want rubbish results; Dolby B only works properly with Dolby B recordings, and the same goes for Dolby C (and Dolby S too). You also appear to have set the bias to max, which will kill the high frequencies Others have mentioned the Azimuth which basically means that the recording and playback heads should be at exactly 90 degrees to the tape travel. It doesn't actually matter if it isn't quite accurate, so long as you play the tape back on the same deck you recorded on. If the playback deck has a different angle to the record deck, sound suffers. This is one of the reasons, apart from terrible quality tape, that pre-records often sound so rubbish because they just didn't care about accuracy so long as they got the money. Modern tape quality is also utter rubbish, being more akin to that of the the early 1960s when cassette was just a medium for dictation machines; peak time for tape quality was probably the 1980s and early 1990s. Now we just get the most basic ferric formulations. Anyone who thinks that Dolby just muffles the sound is either using rubbish tape, or has the deck set up and calibrated incorrectly. I have a machine from the early 1990s and no-one has ever been able to tell between a tape and the CD it came from when using Chrome or metal tape. As with all analogue sound, setting equipment up properly is far more critical than with digital. To be honest, if you really want to get into high quality cassette sound you need to find a well looked after 1980s ish deck and get some decent tapes from the same era from ebay or similar (they're not cheap nowadays unfortunately). By the way HX Pro has nothing to do with noise reduction, but is a record only technique that improves high frequency reproduction.

[@vidtech2630]

I'm not a fan of Dolby, but to be fair some cassette tapes can handle it better than other cassette taped. And on real chromium dioxide cassette tape .

[@HostiaRecords]

That new pre-recorded tapes are worse than the last ones with DOLBY NS, uses very bad tape (makes a lot of hiss) and is still recorded on high speed equipment

[@rodrigobelinchon2982]

Dolby was great on pro equipment,but the truth is Dolby B or C does not work , but hey, you had that cool logo on your equipment . Dolby Pro Logic was great , though

[@sneskid78]

Dolby B and C work quite well, but due to Dolby NR being a compander based system, conditions have to be right. If level calibration and head alignment is just the slightest bit off, you will start getting that dull and often times “pumping” like artifact. Not to mention there were many people who just assumed you could switch it on for anything and it would automatically give good sound. When it didn’t, I think some people just gave up on it without bothering to learn how to use it correctly.

[@mr.spongylikeaboss4987]

If you have a properly serviced and calibrated tape deck, then it is transparent. It goes double for multiple decks. The Playback Level and Head Azimuth have to be exactly the same between the decks, if they are.. they it will work well.

[@rodrigobelinchon2982]

Happy to hear it worked for you , but if you need a 3 Head deck with Bias control , I still think it is useless . Only 1% of the population had a deck like that . I had a brand new AD WX737 by Aiwa , mid of the range in its time, with HXPRO , B and C , and still was disappointed with the Dolby results. Cheers !

[@mr.spongylikeaboss4987]

So many things wrong with this video. 1:Dolby level is NOT where your peaks should be. That is there to help you adjust your meters when playing a Dolby Test Tape. 2: For Dolby to function correctly, a cassette deck's playback level needs to meet the spec of the chipset used in that particular deck. Your 30 year old decks have drifted enough, that the Dolby tracking is "off spec", meaning there will be errors. 3: Head Azimuth has to be dead on for Dolby to work properly between different decks. I can assure you, on a properly adjusted deck., Dolby NR works flawlessly.

[@adamdavies163]

Maybe, but this was a consumer technology, most users would not have the means, interest, nor expertise to align, clean and calibrate a cassette deck to this degree (or any degree in a lot of cases). As I remember, I used to record Dolby C onto quality tapes with a well maintained, decent quality, 3 head HxPro deck. The recordings would sound absolutely spot on for the first few plays, then you would start to notice slight variations / hunting in the high frequencies. I could never understand this. Perhaps the 'Quality' deck I had wasn't so good after all - who knows? I therefore stopped being a fan of cassette tapes many years ago. Yes Dolby worked, but it was way too finicky.

[@marcisberzins]

​@@adamdavies163 After each playback high frequencies on a cassette are lost by small amount, so every time the "mistracking" goes bigger and bigger compared to where the sound spectrum should be.

[@lukasgayer5393]

The only Dolby that worked well was Dolby S. The others never did.

[@patrickgajadhar5723]

I use only DBX With a calibrated cassette deck. Much better noise reduction system in my opinion.

[@darinb.3273]

As long as you don't attempt playing them in non DBX equipment your okay. But playing a DBX encoded tape in decks without it will sound absolutely terrible.

[@Albee213]

Pre-recorded cassettes were almost always garbage. Dolby worked well with a good deck and good tapes. Buying new cassettes now just sounds pointless when the technology is even worse than before. You would be better off buying the LP/CD and making recordings yourself than wasting money on pre-recorded units.

[@tacofortgens3471]

Only good dolby was domby DBX , can record at +5, +6db with ease, could not hear any difference from CD. other dolby NRs sucked

[@marcisberzins]

Dolby DBX yeah!

[@acefrehley3797]

DECKS DO NOT HAVE DOLBY A. LATER DECKS HAVE DOLBY S. AND DOLBY HX-PRO. USED BY RECORDINGS DOLBY HX-PRO ON EVERY DECK WITH HX-PRO. YOU HAVE THE SAME QUATITIE. BUT BY DECKS NOT HAVING IT. THE LEDS WIL NO MORE GO SO FAR OUT. IF THE DECK HAS A MPX FILTER. TURN IT ON. NOT EVERY RADIO HAS A MPX FILTER. AND YOU HAVE TO CLEAN AND DEGMATISEER THE DECK IN THE ADVISED TIME. YOU HAVE A GREAT RECODING.

[@tatsumasa6332]

I want Dolby on my girlfriend.

[@Amper-o-mat]

To hear the effect of Dolby,you should record a tape with dolby ON,and always play it back with dolby OFF...Dolby is playing a fine role in recording,not so much in playbacking,except when playing back at high volume and power( in clubs,for example...)

[@TREW24]

record with dolby B on, playback with it off

[@jaysomewhereinflyoverterri735]

Having been born in 1963, listening to music since then, and now almost 60 years old, this lover of rock music would like to give his opinion of Dolby noise reduction technology. Dolby A sucks, Dolby B sucks even more, and Dolby C sucks so bad that I'll say no more about that. I remember the 80s when Dolby was touted as the greatest thing since sliced bread. The 80s, in my opinion was the greatest decade for rock music with but one exception, Dolby. Dolby sucks, it sucked then, it sucks now, and I doubt if it will suck in the future because nobody uses such a sucky, stupid method of noise reduction anymore because it sucks so much. But seriously, if anybody would care to ask me what I think about Dolby, I would tell them that it sucks. So, in conclusion, I would like to say that Dolby sucks. And now, please let me have a Joe Biden moment here to say, what I haven't said here before, and say that Dolby sucks. IT SUCKS!!!!!

[@mr.spongylikeaboss4987]

No, it doesn't. I've been using Dolby B and C for decades. However, all of my tape decks have had their levels and azimuth matched. Dolby requires a specific PB voltage level.. if it's off, then it will not work right. Head Azimuth has to be correct. Even the slightest difference will cause problems. However once a deck is calibrated, it works wonderful

[@claudeabraham2347]

Dolby doesn't suck. But low end cassette decks suck. Dolby is effective at optimizing SNR, but low end decks have problems that Dolby cannot correct. 1. Wow & flutter. A poor transport will muddy up the sounds if it cannot keep constant speed. 2. Playback head. A low end deck usually has an erase head, plus a record/playback combo head. The frequency response is generally not as extended in high frequency region as discrete record & playback heads. This results in suboptimal treble. 3. Bias & sensitivity adjustment for various tape formulations. Due to cassette low speed of 1.875 ips, getting best results from any tape type requires optimum bias & sensitivity settings. Over-biasing will suppress treble. Under-biasing increases distortion. So, low end decks seldom offer adjustments. 4. Over-recording greatly suppresses treble & increases distortion. Many buffs are obsessed with maxing SNR. So they blast the record levels well beyond 0 VU, into red zone. This way they feel they are covering up noise. But if Dolby is used, especially C type, the tape bias noise is reduced by 15 dB, & is practically inaudible. No need to red zone the meters. If Dolby is used, recording at or below 0 VU keeps distortion low, & treble response flat & extended. But those who record way above 0 VU are reducing their treble. Dolby mistracking reduces treble further. Nearly all treble deficiency problems are due to over-recording. Bottom line - Dolby has been getting a bum rap way too long. Dolby is so effective at reducing noise, one can record at moderate levels to keep distortion low & treble flat. Dolby does have a problem. If the treble is too strong, Dolby makes it stronger. But seldom is a cassette deck too strong in treble. If treble is weak, Dolby weakens it more. This is known as mistracking. But a very good deck with 3 heads, low w&f, adjustable bias/sensitivity, with flat response to 20 kHz, will benefit greatly from Dolby with little treble loss if any.

[@blade3120]

dolby nr WORK ONLY FOR RECORDING VOICE NOTWORKING RECORD FM BRODCAST OR AM BRODCAST!! NOT WORK RECORD CD DISK OR RECORD MP3 TO CASETTE!