DOLBY NOISE REDUCTION - Was it GOOD or BAD? Live Audio Comparison of Dolby B and C on Tape

Whether you like Dolby NR or not, it's a thing. I've always tended to not use it, but I still think it's an ingenious solution to a nagging problem on cassettes... tape hiss. In this video, we'll learn how Dolby B and C work, as well as do live comparisons with and without Dolby on Type I, Type II, and Type IV cassettes. Let me know your thoughts in the comments below.

**NOTE - After posting this video, I noticed a lot of background hiss on the recordings, even the digital file. Turns out, recording from the headphone output on the deck was introducing noise. I've upgraded my setup to allow direct capture from my tape decks, so future videos will sound MUCH better. There's a full update on my Patreon page for those interested**

#electronicscreators #vintageelectronics #electronics #cassette

[MacXpert]

It seems like there are some issues with your equipment. There's an awful lot of noise and distortion in the sound during the demonstration. Even during the 'recording' part where you played the 'original' there was already a ton of noise in the sound. That should obviously not be the case. The playback that followed after that sounded extremely muffled and distorted. This is NOT what tapes should sound like, played on a well maintained and calibrated cassettedeck. Other channels like 'Cassette comeback' show what tapes can actually sound like. Even without Dolby they can sound a lot better than what is demonstrated in this video. This video might give people a completely false image of what cassettes sounded like.

[paullongtailpair]

Before doing such a "test": You have to calibrate the recording level, bias and if possible the EQ ( this have noting to do with the 120/70 us ) for every tape used, certainly using DOLBY C ! DOLBY C needs the record level correct within 0.3dB and a descent flat frequency response to operate properly. By the way, your TASCAM 112 has audible flutter.

[analoguecity]

I'm a vinyl guy, but I enjoy a good type II or type IV metal from time to time! I agree with you 100 percent, NO NOISE REDUCTION PLEASE! 😊

[nethoncho]

I was never a fan of noise reduction either... Thanks for making and sharing your videos.

[octopuscorsica]

I think all excerpts in this video sound equally hissy. As you point out in the video description, that is definitely due to using the HP out of the deck. I have found this to be the case as well when capturing cassette tapes to a portable digital recorder. Always use the line outs of the deck, bypassing the deck's crappy in-built HP amp. As for using Dolby: I find it too much hit-&-miss to be of practical use. You need a deck with level calibration to make optimal use of it and it does not transplant well to other cassette decks. I record without Dolby and then route the tape signal through an external single-ended denoiser. 30 dB noise reduction is feasible and a digital capture of the tape signal is hard to distinguish from a CD original in an AB test.

[Ryanse]

For me, it depends on how I plan to use my cassette. Dolby is heavily dependent on azimuth. Playback on another machines with Dolby which aren't in perfect head alignment with the recording deck, will usually not give favorable results with Dolby switched on. They can often sound dull and lifeless. If I am making a cassette that will be played back on other machines, I will usually opt for no NR unless the recording contains quiet spots and I am on a Type I tape, then I'll encode with B. If I am making a cassette that I plan to only play on the deck that is performing the recording, I will opt for C. My deck doesn't have S but I am interested to hear how that compares to C. Metal cassettes have lower floor hiss by nature, so you can certainly get by with recording with no NR on those if you have money to burn. When a metal cassette is played back on my recording machine with C Dolby used, there is absolutely no hiss at all. Only the amplifiers transistor hiss is present. Sometimes, as you mentioned, I will record on type I with B NR on, even if the cassette will be played on another machines without Dolby, because the only draw back is usually exaggerated highs which can be corrected easily through tone or treble adjustment. So, my opinion on this is - If you are planning to play your recording on other machines, it's probably best to leave Dolby off. On type I tapes you plan to play on other machines where your recording has quiet moments, I sometimes decide to record with Dolby B on. On those types of recordings you might get lucky on another machine with Dolby on. If you are only playing back on the deck doing the recording, shoot for the moon. It will sound fantastic!

[DoodiePunk]

Wow! The dolby was confusing the original treble with noise. I agree with you, in your demonstration, using no dolby at all sounded better. I wanna hear a dbx demo.

[johne]

Type II/IV tapes generally don't need noise reduction as they can accept higher strength signals, thus giving them higher signal to noise ratios as well. It's normal tapes that noise reduction systems are mainly meant for. Dolby B was good for reducing noise but higher frequencies were still weak. Dolby C would make normal tapes play back with greater clarity and cleaner sound, like their high bias counterparts.

[CraigTube]

I never get this bad of a result from my less expensive deck. How are the heads on that Tascam? Your results were horrible compared to what I get with my deck, which is probably half the price. None of my tapes EVER sounded that bad, with Dolby on or off.

[zooomm]

I'm impressed by the wow and flutter stability of your deck, but it seems like hiss a little higher than what I'm used to.

[SFtheGreat]

I'm not using NR when recording. I would like to see comparison with S though.

[markthomas]

Two crucial points for me are these-- if you use an equalizer, you can boost the treble compass of the cassette when Dolby is IN. That really helps bring up the highs which have been attenuated by the NR system. Secondly, all normal bias tapes are JUNK, people. They were made for VOICE DICTATION. That is it. They were never meant to be a hi fi system. You have to at least step up to type 2 or better tapes to get the treble compass needed.

[Mikexception]

I use the same Maxwell UR C60 Ferro and I must say that I do not accept with them any noticable change of sounding. But my decks ( I use two) are tuned by me exacrlty to meet that result. I wonder (some may say it is conspiuracy theory but it could have good economy reason) that producers tuned decks so that they would sound a bit foggy with Fe in opposite to say Cr. I personaly could not prove it technicaly supported - both kinds of tapes sound without sound issues and that is why I prefer Ferro over switching to Cr and worry about head.

[tenej]

Dolby noise reduction works only in the most optimum circumstances. Clean tape path, right head height, azimuth, tape speed, tape calibration and level. If you don't, tape will most likely sound muffled. People don't want to go the extra mile to get their decks properly calibrated, so they just rather be stubborn and say that dolby nr never worked and just never use it. But when it works, IT WORKS. Dolby S plus a metal tape is as good if not even better than a CD.

[CraigMecak]

Why is there so much noise/hiss in the first place on the Original File? Makes analysis of the NR types a bit moot.

[apmcd]

I haven't watched this. I've always thought that Dolby Noise Reduction had Snake Oil written all over it.

[akirastate]

I remember Dolby noise reduction. I used to record from sources like vinyl records, and I would get good results using Dolby B noise reduction using Chrome tapes. However, using Dolby C, which raised the signal to noise ratio, tends to sound pretty crappy on equipment which didn’t have it. Most of the more expensive portable tape players did have Dolby B noise reduction, but not C. However, it did matter as to which type of tapes were more suitable. Using Type II or Type IV have better frequency response compared to Type I tapes. Most of the portable cassette players only supported Type I tapes, so you would need a higher end player to play back Type II and IV tapes.

[MrROTD]

B and C worked great if you recorded and listened to the tape on the same deck for sure but it might not sound so good on another deck. I used chrome cassettes mainly TDK or Sony were my faves but also Fuji had good ones. If you set the level just right it was way better than nothing because the hiss and lack of dynamic range of a raw cassette was not very listenable. If you had a type 1 tape with no dolby it sounded like gravel. Does the youtube compression affect this? I remember hearing the hiss much more even with better tapes.

[briangoldberg]

I couldn't hear any tape hiss in any of the recordings through the video. In my systems, I can hear the hiss quite clearly, and Dolby B gets rid of it very well. I think it's good, so long as your equipment is good all the way down the line. The way Dolby is supposed to work is that it accentuates those frequencies in the recordings that are then lowered during playback, so there shouldn't be a dulling effect to the high frequencies. If you're perceiving a dull sound, then there is something weird going on, like maybe the biasing of the cassette isn't quite right during recording or something? Somehow, you are losing high end that wasn't properly added into the recording. That doesn't happen for me at all, Dolby B has all the highs and sounds crisp and clear as a bell. C is generally bad because it's too complex and recording and playback rarely matches up well from machine to machine. Dolby S on the other hand is better than all of the others. S tapes sound great played back with no Dolby and with Dolby B or S engaged.

[LostBeetle]

You were super over biased on that type 1. Proper bias and a type 1 sounds very good with no loss of treble. In my experience with NR, it can sound very good, but there's still something missing and some music makes it apparent, a quiet trebly instrument buried behind loud mids and lows will sound slightly quieter using NR. But not always. Best to leave it off, no processing, just hear what's actually on the tape. Dolby is a cheat that doesn't quite work perfectly.