You're technical assistant is the stuff of nightmares.

Watching this video has rekindled my interest in my old cassettes (all with Dolby off). I haven't played them in over 20 years, but I've now dragged out over 200 cassettes, cleaned and demagnetized the heads on my trusty old Sony TC-FX510R and here I am happily reliving the past. So, thank you.

I always used the Dolby switched on. You are 100% correct: if you get a dull sound from Dolby, it's the misalignment of the heads. Another reason is that the tape used was over biased when recorded, or just plain bad. I suspect most complaints came from commercially-duplicated tapes, which were mostly bad. They were duplicated at very high speeds on the cheapest tape possible to save costs.

Despite proper cleaning and demagnetizing, as an owner of multiple cassette decks, the main problem with HF roll off was due to azimuth head misalignment, exacerbated by Dolby encoded tapes. Had I known this would be an issue at the outset, I would have recorded all my tapes without Dolby. Now the solution is to use decks with adjustable azimuth played back with Dolby.

Ever since 1982, my favorite Dolby has been Thomas Dolby. His stuff always sounds ace!

Dolby B does work, however most pre-recorded tapes sounded better with it off and adjust the treble as needed. With it on you needed to crank the treble to make it sound good. When I recorded cassettes on a good deck it was great. Dolby C with type II or IV was great with a good deck.

I had a separate dolby unit for my reel-to-reel deck. My friend had an enormous record collection and I would borrow from him and make a dolbyB encoded reel-to-reel copy at 7 1/2"/s. They always sounded as good as the LP.

I’ve been playing with a nice Dolby type S deck and metal tapes and I’m actually very impressed by how good it sounds. It’s a lot of fun to see how far an inferior technology can be taken with technology

This is a perfect illustration of how analogue recordings are vastly more dependent on the playback equipment (both quality and condition) than are digital recordings. I've been using cassettes since the 1970s and I have never felt that Dolby was less than excellent; but I've always had an interest in the technology so I wouldn't dream of using a dirty machine, crap tapes, wrong bias, or recording at the wrong level, etc. My current three head machine with Dolby S essentially makes recording that are indistinguishable to the ear from the source, be that vinyl, CD or whatever. However, one thing is certain - pre-recorded tapes almost always sound crap because it would have been too expensive to use decent tape stock or record them at only 1 7/8" speed (+ precise azimuth and probably loads of other factors).

One feature that sadly was adopted only by NAD (who developed it) and Yamaha was Play Trim, which applied adjustable EQ to the signal before it was sent to the Dolby NR decoding circuit to compensate for alignment issues. It was pretty effective.

You've stated it exactly correctly. For 28 years I aligned tape machines physically and electrically, using Dolby-A, B, and SR. Unfortunately the public has not yet acquired "our" level of discernment as to appreciate the value in "hearing" something in the way it was intended (wide dynamic range and balanced spectral curve), they would just crank up the bass and treble anyway, especially in the noisy A** car. Really just listening to un-decoded B-type tapes, makes-up for a dirty cassette deck in a pretty nice way.

Nakamichi DR-2 and DR-3 owner here, nuf said 😊 Also bias matters, I missed that in the video. And of course, sensitivity and azimuth. My cassettes from the nineties, almost always recorded with Dolby C sound still terrific. Sometimes I play one of my old cassettes in my DR-2 and I'm amazed at how they still sound magnificent on my main system.

I'm a member of the Dolby B team. However, I use a Denon 3 heads for recording and I record at the highest level possible on new-old-stock chrome tapes, then I listen on another 2 heads Denon because I don't want to use the 3 heads prematurely. After watching your video, I now understand the meaning of the dolby sign on the Vu meter, it's the Dolby trigger. I didn't know that

When I was still using cassettes up to the early 2000s I just used maxell xl-ii with no noise reduction. It seemed to be the best at leaving good response on lows mids and highs. Sure there was some noise, but I could hardly hear it except for maybe the blank spots between songs.

Back in the day I used to encode with dolby and play back without, for the extra treble zing. I probably wouldn't do that now.

The biggest Dolby type-B issue was with store bought music cassettes. No matter how much cleaning, degaussing, and aligning, of the heads was done, the mastering deficits just wouldn’t allow enough clear signal for the noise reduction to perform its task properly.

At the time I went for DBX😄 A while ago I restored my ‘good years’ Technics RSM-255X cassette deck and listened to those old DBX tapes. I was surprised about the high quality of those 40 year old tapes in the 40 year old deck!

Also the HX Pro & AMTS features really help along w/ metal tape. . I have found that to get the right record levels, it helps-- after recording a track-- to let it play back once all the way through before checking the level. The sound will embed itself onto the tape at a lower level than if one checks it directly after recording. Thanks for you channel..

Great explanation. I really like your clear technical approach.

I only tolerated compact cassettes in my youth when I recorded LPs to them. I never engaged Dolby noise reduction because, like you said, it dulled the sound. I never understood what the big deal was with Dolby NR, no matter what letter they used.

In 75 I bought a Teac 3340S and a Dolby unit that was recommended to me for quieter recordings. I used it for a week or two making encoded recordings that then had to be played back through the Dolby box to unencode what was recorded. I don’t know if I wasn’t using it properly or what, but it seemed like the recordings just didn’t sound as good compared to not using it in the first place. I returned the Dolby box to the dealer and am glad that I haven’t had to deal with it. I used that deck to record a lot of my original music into the 90s. In recent years I have archived most of my old tapes into my daw and am quite pleased with the quality of my old recordings.

I remember experiencing the high end boost when the Dolby switch was off but thought that people were just hearing the boosted high end and preferred that as a psychological comparison, kind of like people prefer the sound of something that's a bit louder than what you're comparing it to. Thanks for clearing up the mystery.

Some times I like it switched off and sometimes I like it switched on, but I learned a lot after the explanation about how the system works, thanks for that

As a teenager I really wanted a Nakamichi Dragon or CR‐7E, or even that AIWA one that let you adjust head azimuth.

I've just discovered your channel and I'm loving your vídeos. I think that set the 400 Hz level for each kind of tape, clean the heads and capstan, demagnetizing the heads, etc., is part of the analog enchantment. As with overhang angle, anti skating, compatibility of the mass of the arm with the capsule, etc., etc.. The hifi is for the ones who love it. Sorry if my english is incorrect, but I haven't trained it for more than 20 years.

I was taught to get the bias for your tape right, and set the (pre)rec level correct as well. My last deck had bias and (pre)rec level adjustments, next to the normal recording level, and with 3 heads, tuning was easy. Then Dolby worked fine.

Back in the days when it was common to send a client home with a rough mix on cassette we used to use Tascam 122 cassette machines biased for TDK chrome tape. These copies never had Dolby B applied and sounded terrific. My production reel to reels also did not use Dolby, we inserted dbx noise reduction and it was (and still is) fantastic.

I remember an interview with Ray Dolby where he was relating the problem of explaining what he did to the average party-goer: RD: You know that button on your cassette deck? PG: Yes! What does it do anyway? RD: It reduces noise. PG: What noise? I used dbx with metal tape.

My home deck is a harman-kardon hk400xm that does all 4 tape types with manual calibration facilities. Needless to say, it has Dolby Type B as well as HX Pro. I play these cassettes in my car because I drive a 1997. It sports a cassette player with Dolby and has been regularly cleaned and maintained by myself for 26 years. Friends and co-workers of mine get in my car, and they don't believe me when I tell them they're listening to a cassette. I have to eject the tape and prove it to them, and they are simply blown away by the sound quality. None of them knew cassettes could sound so good. This just goes to show that cassettes can sound absolutely amazing if you have proper equipment that has been maintained and that you know how to use correctly. Yes, Dolby absolutely does work. I've been proving it for decades.

In my experience, it works pretty well so long as it's for your own recording played on the deck that recorded it, and some decks are very well aligned with one another. Pre-records are definitely a hit and miss, some have given the correct treble response when compared to a streaming version in a/b tests. But no matter how good you can get it to work, some sounds (mostly high textured electronic sounds) can lack detail unless you under bias, but that will also give a treble boost to everything else. Leaving dolby off during recording will keep those problem sounds more intact. 99% of vocal and instrumental music dolby will stay faithful to the source so long as you have a proper bias adjustment making pink noise match the source indiscernibly at 0db (yes even a two head deck with the internal pots adjusted), you won't be able to tell the difference in an a/b test, even with good headphones, volume cranked high. It's just those electronic sounds that go above and beyond the capabilities sometimes. If someone doesn't believe me, generate a sawtooth in audacity, record it onto cassette at 0db, then play it back comparing it to the source sawtooth (match the volumes if required). It will be missing texture, far worse so if you used dolby.

Nice video brought back alot of memories. I used dolby B when recording CDs. I used high bias cassettes and with dolby B engaged they sounded pretty good. Also the stuff about head cleaning and alignment made me reminisce about the good ole days😁

Appreciate your previous response to my precious comment on sibilance. Looks like you’re in a different room that would reinforce your answer that your direction in the previous room was to blame not your gear. Sounds great in this space on the same mid-fi gear on my end. Thanks for another great video.

My Aiwa AD-F770 calibrates automatically for each tape you record onto, very useful. I used Dolby B for tapes to be played in the car (yes, Dolby on the car stereo too, only recently removed it) and Dolby C for home recordings.

What an amazing channel and content, i love it so much.

My first encounter with the Dolby Noise Reduction process came in the form of a stand-alone component made by TEAC, the AN-50. It required 4 pairs of stereo patch cords connected between a single tape recorder and the amplifier. The feature that I found most useful was a built-in 400hz tone that I used to set VU levels. The unit did clean up and improve the sound quality to some extent, but I took a different approach to resolve the source of the noise which was to record on higher quality tape to begin with. I still have the AN-50 and use it as a tone generator. I have had no need for the Dolby process all these years with clean recordings across the board.

Thank You Sooooo much. Finally the missing tutorial on Dolby. Again, thank you!

D B it works well enough for me when used correctly. It also worked really well when a Dolby encoded tape was played back in our old car cassette, non Dolby, player...helped lift the music above the car & road noise.

Very good description. Since my very first cassette deck i paid attention to have a Dolby level and bias calibration on the front plate, so my recordings always were with Dolby B and for my second deck Dolby C. I went the extra mile to also have a Walkman with Dolby C. I still record mainly in Dolby C. I did also discover DBX (II Type) can sound very convincing too. Pity there was only one walkman ever available with it/ or a external processor for mobile use. As i now have about 100 Tape decks in my collection (also with Dolby S) I'd say Dolby S is one of the best systems for cassette. The only drawback is that it was too late to the party and only a select few decks with good mechanisms were made.

I still own a Yamaha KX-200 with Dolby B and C. I used C for recording but never for playback. As they say in Spinal Tap; "You shouldn't do rock albums in Dobly". The KX220 is no longer in my system though. It's languishing on a shelf in the box room. Best sound I ever heard from cassette was from a Fostex 4 track owned by my mate which ran tapes at 2x normal speed for home recording. A 90 minute tape lasted just 22 minutes !

In the 80s the studio I worked in used had dbx noise reduction rack units for each track on both 2 track and multitrack machines - lots of rack units. We thought that worked very well. At home on my cassette deck, I never used Dolby B - even tapes recorded and played on that machine sounded dull to me. But the deck also had Dolby C, and I actually thought that worked well for my own recordings. I used it all the time. Not sure the difference between B and C. Will have to look it up. Thanks for the memories!!! No wonder we were so happy to get DAT! :) Love your videos!

I clearly remember a friend saying "hey that sounds much better" when I switched the Dolby off, being a little perturbed as I am a techno geek and of course if the tape was recorded WITH Dolby so it MUST be played back WITH Dolby! Regardless of how it sounded I would stick to my "geek" guns. Then along came Dolby C and of course metal tapes and being an avid fan of head cleaning, de-magnetizing and correct azimuth & "variable bias" I would spend hours working out which sounded best. I spend so much time on this that I forgot to just sit back and enjoy the music. One day the same friend came over and suggested again I switch the Dolby off, so I did, and very quickly I heard an awkward "nah switch it back on it sounds better!" These days I just log into my TIDAL account, click my mouse and just sit back and enjoy the music - at 66 I no longer feel the need to labour for hours or days getting the right settings - I sit back and enjoy the music, which is what I should have been doing 50 years ago!

I used my Nakamichi ZX7 with metal tapes, usually TDK, and the Dolby C switch in the 'on' position always, for about 20 years. I don't use the deck or the cassettes anymore, but it worked great through the 80s and 90s. Still have the vinyl records and the CDs I bought in the 90s and 2ks. The vinyl records are the best in the end.

Thank you for posting.

I had a home tape deck and portable tape player from same manufacturer that had b and c type - sounded great to my young ears 😁

You had me at your assistant's first utterance, and you won my heart with your hysterical expressions admiring her from your little bubble as she spoke! New subscribe here! You missed discussing type C. It's easy for me now - I have recorded one cassette in the past twenty years after getting my hands on a nice pioneer deck from the 80s, and I can't hear > 5KHz worth a beep anyway so hiss away tape, I recorded without it. Forty years ago I did use it on prerecorded tapes with the logo and turned it off for those recorded without. For my own recordings, I found it better left off because as a kid I bought TDK or Maxell midprice tapes typically or whatever was on sale when I was running low on blanks, so I got inconsistent quality recordings and therefore dolby was imprecise on playback and annoying.

I was never a big fan of Dolby NR. If I used it for a particular recording, it was B-Type, never C-type. I think it also has to do with the fact I didn't know at the time how it worked. Only recently I learned more about it, since I started experimenting with the software tools described in my comment on your previous video. Now I only use dbx on my cassette deck with dbx or via software DxII on the other deck. I love dbx.

I leave Dolby on and I always try to match it to the correct Dolby. B recordings to B and C to C, etc. Although these days I tend to make my recordings in C. The recommended tape for my deck is TDK D, but I use a wide variety of tapes that work fine. TDK D, Memorex DBS, Maxell XL II, UR, BASF you name it. But my favorites are the D, the DBS and the XL II.

My ex-girlfriend liked when I recorded her tapes with Dolby-B so she could play them back without the Dolby... she's way cooler than me. She loved the blistering high-end. Most professional recording engineers I knew recommended against installing the Dolby-A system. It was just more equipment that had to be calibrated and reduced the number of machines you could playback with. More stuff to go wrong. Better to have a properly aligned Studer A827 without noise reduction. I had a Technics cassette deck that had Dolby-B, Dolby-C and dbx. Dolby B actually worked fairly well, but it was a nice and well maintained machine. Dolby-C was muddy. dbx (compander) was abysmal.

This may be an explanation, why I sensed that Dolby only was working „from time to time“ and decided to switch it on or off by ear depending on the tape played back.

Many people don't even understand that Dolby ANYTHING is a 2 way process. You cannot just throw it in if the tape was not encoded in the first place. This lack of understanding was not just for the domestic market. In the early days of analog Prologic for cinemas, prints would arrive at the cinema often Dolby A encoded. Even if the cinema was a mono none Dolby sound system. Playback sounded quite odd. Very compressed and over bright. In later days trailers would arrive as Mono, stereo with or without Dolby A. Mostly with no identification on them. Not that it mattered anyway. With multiplexes and mostly nontechnical staff. The Dolby was activated ALL the time, even in mono. Simply because few understood the implications. (or did not care!) I've even had a Brenda Lee CD where Dolby A reduction had been applied to a none encoded track in the first place. Sounded dreadful, taking it back to the shop was a pointless exercise, they had no idea what I was talking about and could hear nothing wrong. Ahh, those were the days!

One of my decks has autocalibration and I have a small collection of 25 different Type I and II cassette tapes from brands including Maxell, TDK, BASF, Sony and Philips. I'd say the deck can calibrate itself properly (ie. with a maximum difference of 1-2 dB between input and playback level) to 50-60% of those cassettes. In these cases, recordings with Dolby B or C sound excellent. That is, as long as I play them back on the original deck. Overall, I find Dolby to be fiddly and very sensitive to alignment differences between various decks, as you pointed out. I do not bother with Dolby anymore ever since I put an external single-ended denoiser in my playback chain.

Dolby should have made playback level adjustments available on all decks with Dolby NR to reduce the compatibility problems. I still have some more than 30 year old Dolby B/C recordings on TDK and Maxell tapes that sound almost perfect. But most pre-recorded Dolby B tapes did already sound a little dull when they were brand-new.

I still have a Revox A77 and an external Dolby box made by Advent 100A. It works great. If you play a tape that was Dolby encoded with Dolby switched out, it plays with excessive treble. Some people equate this with "better".

I knew the Dolby B button worked and it did reduce tape hiss but I always found it dulled the high frequency of the music too.

My first cassette deck had Dolby C, and I thought it worked quite well, but I always used the best quality blank tapes I could afford and I never bought pre recorded cassettes. I did sometimes resort to switching the Dolby off when playing the few pre recorded cassettes I ended up with to compensate for their poor quality.

I've got 40 TDK and 5 BASF Chrome tapes all recorded with Dolby C and they still sound fine (not dull) today. I do clean the heads and drive parts now and then.

The best results I ever had recording Dolby B tapes was in 1980 using a quite expensive Aiwa AD6900 machine that had a pretty involved manual tape tuning facility which - if used properly each time before making the actual recording - made brilliant recordings that would also play faultlessly on other machines too. A couple of minutes well spent each time before making a recording.

Decent consumer grade, three head deck, Dolby C (encoding and playback) and Metal tape. Maybe a tweak on bias, but sooo close to the disc it recorded from, it was hard for my ear to separate the two. I did not own a Type S deck, but was always curious about it.

I am one those people who tends to switch Dolby off on cassette decks. However, some years ago I made a lot of music on an 8 channel Fostex 1/4'' tape recorder with Dolby C and it worked fine - as long as I used the good Maxell tapes (the machine was probably adjusted for those) and planned which instruments I put on the individual tracks. Since there were only 8 tracks I sometimes had to have more than one instrument on some of the tracks. If I put an instrument rich in treble - like strings - on the same track as the drums, I could hear the strings loose treble when the snare drum was hit and than gain treble again until the next drum beat. But apart from that quirk it worked fine.

i used dolby c mainly on normal tape & no dolby on chrome & metal worked well, hx pro helped as well

I own some Nagra recorders including a IV-S. (2 in fact) Some time ago I found this Bryston 280B noise reduction unit with 2 Dolby SR cartridges in it. Its very hard to hear any difference in the recordings with or without. But I am almost 67 now. So it must be my hearing! The Nagra has always sounded good to me. Yes at 15 inch.

@audiomasterclass I believe type A cost $1000 CAD per track.

I work daily on cassette decks as a nostalgic hobby on the side of my musician life - and have used tapes since the 80s. Dolby C and S are pretty fantastic if you have a clean and well calibrated machine. I use those Dolby types everyday.... never bothered with B. But all the old prerecorded cassettes with Dolby B do not work with Dolby today! They are better without!

It's been working for me on the tapes I recorded myself. The results are mixed on pre-recorded tapes. I used to record with C for years but eventually moved to B, like the overall result better.

Your on a role. Another good video!

In a nutshell, Dolby noise reduction only works properly if the tape head elevation is adjusted to exactly match the tape you're playing, which it almost *never* was with pre-recorded tapes or tapes that were recorded on any other tape machine. Turn the tape over to play the other side and you also had to re-adjust it! When the head alignment is exactly right for the one tape you're playing, Dolby B and C noise reduction were incredibly good--especially Dolby C. Yeah, cassette tape was pretty noisy format and was never intended for music when it was invented and Dolby NR, either B or C, only worked its magic when the head alignment was just right to give the best treble output. Otherwise, it was awful because it would kill the treble output was well as noise.

On my Aiwa Creator's Stereo, the level reads back at about 3 dB less. The sound seems slightly muffled and "digitally processed," similar to fft noise reduction that people often overuse. Since there are no test tones on cassette tapes, I wouldn't know how to align it. If a type I the tape is overdriven, it loses high frequencies, so Dolby would see a radicaly different level. I find the best recording level to be where the VU is barely kissing 0. Holes in the tape also get emphasized by Dolby. The one-sided Dolby-HX works better and allows to maintain high frequencies at higher levels by reducing the bias.

I bought a prerecorded cassette, back in the day, that was recorded with Dolby noise reduction. I also used to use a little screw driver to align my head for different tapes.

I always used Dolby C NR. I also fine tuned the bias of the tape by recording noise of my FM tuner (finding an empty spot where there is no station). If the noise was identical between recording and playback it was ok for me. This gave me good results with my Kenwood cassette deck. I once bought a pre recorded cassette, recorded with dolby-B or normal Dolby as I called it, and it indeed sounded dull. That was the first and the last pre recorded cassette that I ever bought. Of course it is all past tense. I am in the digital age now and relieved of all these goodies I used to love in the past.

I always use Dolby C during Mastering my own mixes from DAW to Cassettes . After the master is made ------------------again use Dolby C during play back and record back to DAW for CD production . My decks are Yamaha KX 800------------TEAC V-870-----------Yamaha KX 580 (2 Head) and Sony 611S . Indeed proper tape tuning is must as all my decks come with tape tuning option. For play backs I use 2 head decks Nakamichi BX 125 ---------------Yamaha KX 300 and Nakamichi BX 2 .

I recorded a bunch of vinyl records using Dolby-B and some using Dolby-S. I’d occasionally A-B a vinyl against the tape I had just recorded and to my critical ears they were quite good.

Dolby B and C helped out great when recording my scratchy albums to cassette. Love cassettes and still record off radio and turn table. Just need some power to drive them.

Back in the day, I used Dolby B on pre-recorded tapes and on my recordings as well and it sounded good to me. I guess it depends on the cassette deck, if they implemented the system properly.

I read about this as a middle aged adult recently and understood it. Would be interested to hear the difference with the proper tape and other conditions met. I won't be dealing with cassettes probably ever though.

You're correct to talk about alignment, and 3 head decks with fine bias help that by ear. My deck generated tones to assist. I used Dolby C too (a video on that?) and I also used dbx, there's a type 1 and type 2 (my cassette was type 2 I believe) but Dolby A sounds similar (in operation) to dbx or have I missed the point?

It worked properly, whether it’s A,B type, C, S, SR… as long as it’s aligned properly at *each deck it’s played on*. which is not always feasible. I spent literally years in the 80’s trying to find a home deck that matched a car deck in speed, alignment, and Dolby tracking. It was horrifying. In the studio everything was aligned before record/playback so that was easy to troubleshoot. I like it and it does work. I used it on just about everything except tape running at 30 ips 1/2”.-

What we need is plugin that simulates all types of Dolby decoding, A, B, C, S, SR (And dbx I & II etc, come to think of it.) I haven't recorded to cassette for going on twenty-five years. I have had to transfer from a cassette provided by a client, (and come across reel-to-reel tapes of various formats that were encoded as well).

I've found that recording in Dolby, and playing it back on Dolby from another player (my car) actually makes a positive difference. Versus not recording in Dolby, and trying to play it back with the setting on.

I used to have an Akai GX31, if I remember correctly, it could adjust itself to the tape by recording beeps and sweeps, playing them back and changing settings until it thought it got it right. It kind of worked.

A Good Alternative in the 70s: Philips "DNL" I made the same experience that is described in this video and never used Dolby B on any of my over 600 cassettes since my first Hifi tape deck in the end of the 70s, that was capable of Dolby B. I didn't want to destroy my recordings with this crap, that, when playing back, reduced high frequencies very agressively when using it with playback, too, or made them too shrill, when not using Dolby at playback. What was very good in my eyes btw. ears, was on my first Hifi tape deck from 1975: "DNL", "dynamic noise limiter" by Philips. This worked like a charm: First I did not have to destroy my recordings, as DNL was for playback only. A huge advantage, as my cassettes were recorded neutral and universal. Second it worked by cutting off some high frequencies at very low volumes, when noise can be heard easily, otherwise it did not filter too much (or nothing?). It is interesting, that in low volume passages I never heard that loss of high frequency, as one could assume. But the noise on the other hand was canceled so much. The handbook of the machine told, that low volume music had automatically fewer high frequencies... I don't know, if this is true (?) So with DNL there was never the impression of missing high frequencies like with Dolby recordings, while noise in more silent parts was reduced very effectively. I dont't understand, why Dolby was such a success in opposite to DNL. Maybe, because with cheap chrome cassettes in the end of the seventies the noise was not a real problem anymore for most of us, especially, when the cheap and very, very good tdk sa 90 cassettes came out.

The key to a proper working Dolby system is that at playback the audio must have exact the same level on all frequencies as on recording. Therefor a good aligned tape must be used. In the 80's I bought the "really good" real chrome dioxyd (CrO2) like BASF or Agfa. But today, some decades later, (omg, I'm old) these tapes lost between 6 to 10 dB playback level, so they can't be played with Dolby on anymore 🙄

(From David) I always have Dolby switched in(on) & utilize Type C when the tape has been so encoded. There are some "noisey" environments, however, in which the sound "improvement" is perceived as limited.

40 odd years ago I was very popular with my friends ,I like to think for many reasons but one reason was that I had a very good Scottish record player and a B&O cassette tape deck with Dolby HX Pro . One of the few decks that had it built in , I made very good tapes for my friends who played them in their cars

It worked great!

With Dolby S and a good Type II tape you can get very good results. But yeah, deck to deck playback is often a variable experience, whether you use Dolby NR or not. I record cassettes for fun, a bit of nostalgia and a physical hands-on experience, I'm well aware of it's limitations, but trying to get an as good as you can recording out of it also makes you really listen to the music, it's not music as casual background, it's something that you're actually involved in, a deliberate process that can make you notice new things about music that you thought you were familiar with.

Nakamichi used to make cassette decks that would adjust their Dolby levels for each brand of tape; you put the tape in and set it to calibrate and it would record a series of tones on the tape and set the Dolby level for recording on that exact tape type. It was a tedious process but was only needed when recording as the levels coming off the tape would be correct if you bothered to calibrate before using a new tape type. Of course if you only ever used one brand of tape then calibration only needed to be done a couple of times a year to get the best out of the machine. Maybe there were other brands of cassette deck that did this but I never saw one.

If the tape machine's heads are clean and aligned properly, of course Dobly NR just works: correct frequency response and tape hiss is reduced. But especially if recorded and played back on the same deck. The trouble was recording on a decent deck then playing back on another (and car players without Dobly) - people got used to thinking the over-bright, compressed HF (and hiss) was normal. In fact, "dolby stretching" (encoding and not decoding) was often used in multi-track tape recording as an enhancer effect on parts such as backing vocals.

Dolby works, sometimes. It's like you said, it's a companding system. But unlike DBX it sounds okay with it off. So, if it isn't working quite up to expectations and you have to switch it off because it's a home recording that didn't have it or for what ever reason, at least you get a boost in highs.

I don't know if this will shed light on anything for others, but I used to own a four-track cassette recorder. The key, in my case, was to use hi bias tape (CrO2). Everybody has a preference, but I came to like Maxells. But the other thing was to make sure to record "hot", where the leds or the needles are in the red zone fairly often but not too often. The proof of course would be in the playback. My machine was a B recorder, had no way to turn it off, and I wasn't complaining anyway. I just learned that it's not just about the tech but how you use it. It's an old trick, this recording "hot", so I read, but that seemed to be the end-run around noise issues, even with normal bias tape."Hot" virtually wiped out the noise floor in my little home studio. My guess is that Dolby B is your best friend while your recording, maybe not while playing a tape on a stereo deck. I do hope this makes sense, and sorry for the long post.

Using the right tape and keeping your heads clean is essential, but that's just part of the equation. The reason why Dolby B failed to decode properly in most decks and portable players was head to tape alignment, or azimuth. Cassettes can play perceivably fine with some minor mis-alignment of the tape as there is a bit of tolerance for mis-tracking. Unfortunately, however, when the audio signal is encoded with Dolby, this tolerance diminishes greatly and so therefore, unless the tracking is pretty much dead-on, Dolby B will not be decoded properly and usually results in the loss of highs and a muffled, lifeless sound. Pre-recorded cassettes were the worst for this, which is why most people thought the tape sounded better with the Dolby switched off. So because of this, the consumer would NEVER turn Dolby on for recording on their own decks. Which was a shame because if they did, they'd discover that: If you played back a tape encoded with Dolby on the same unit that made the recording and encoded the Dolby signal, it worked perfectly, with no issues. Why? Because it's tracking dead on! Of course, if you're using shit tape and not cleaning your heads, it's not going to work then either. :)

Dolby S did a lot to improve the higher frequencies in consumer-level tape decks. That one really worked.

Dolby NR has been a 'goto' ever since l discovered it as a late teen many years ago. It worked well for me and was never an issue on any of my recordings. PS Love the channel 👍

Dolby Noise Reduction was great on cassette tapes No Hiss….. I with it cam out when you played a Vinyl to reduce the crackle sound, Apparently just before you put the middle to the record, put a fine mist spray of water over the face of the LP then play it, 80% of the crackle disappears 😮

Yes, Dolby button In always. TDK SA & SAX was my go to tape on my trusty old Nakamichi 600 tape deck.

Audio cassettes existed for one purpose only - convenience. They were a way to take the music of your choice with you, and you accepted the 'worse than AM radio' sound as a price you had to pay.

I found not over-biasing and creative use of saturation to be way more important. NR is just a bit of extra icing for dynamic range

I saw a documentary about Dolby Noise reduction, and in the 60’s when Type A was being sold to professional recording studios, they cost about £10,000 which is still a large amount of money, but back in the 60’s semi detached 3 bedroom houses cost about £2000 .

Whenever my and my buddies had a recording session in the late 80's that was a hot topic 🙂. Initially we fought over, but on the later times we just leave it off.

You can believe what you want. I could care less about this noise reduction as it took the life out of recording. I used to use it, but it took out more than it opened up. Most could care less about recording analog regardless which tape format they use. I choose not to use it anymore. More circuits used equals more chance of noise introduced into the signal path. You choose what suits your situation and needs. Your ears are the only ones that matter in this hobby.

My decks are the Denon DRS- 810 & AIWA AD-F700. MO is that using Dolby C actually enhances the sound. See owners manual for DRS- 810 pg 10