Dolby? dbx? Which is best? What do you want to know?

In this video I'm going to ask you what you would like me to cover about Dolby and dbx noise reduction systems. Tell me in the comments what you want to know, and also tell me your experiences. I'll put it all together in one comprehensive video and really find out which is best.

CREDIT
The chart in the poster is claimed by Wikiwald as their own work, CC BY-SA 4.0

[paulpavlou]

Hi David, My old Nakamichi 600 tape deck has three noise suppression options which included the obligatory Dolby NR, I..M Suppression as well as MPX of which I used all because I didn’t know what I was doing back in the early eighties. Dolby works for me in my surround sound receiver or my surround sound processor otherwise it’s irrelevant to me these days. I’ve never used or had any equipment that had or used dbx in its implementation. I love you work and videos thx.

[gregorykellerman]

After a quick perusal I don't see that anyone mentioned the dbx 3bx, I used it extensively to increase the dynamic range of vinyl back in the day. I have a recording of Star Wars and Close Encounters by the Boston Pops, on one track it pushed the signal down 20 db and then suddenly up by 12 db. I'm guessing the total range must've been about 90 db. If you weren't expecting the sudden change you DID jump! :-)

[MartinMaynard]

I ran a medium size cassette duplicating plant from 70s till 2000 making a lot of the independent labels tapes like Rough Trade and all the early Oasis tapes. We often had the request not to use Dolby and this lead to some upsets which lead to complaints that the tapes sound dull. We found that people liked the tight bright found that dolby comparison added to the sound and listened to with the dolby replay switch turned off. Later on our Dolby encoder was used as an outboard compressor as an effect, great on vocals and strings.

[johnhricko]

As u mentioned, s/n & dynamic range are so great, we now filter that through 'simulators': mic sims, console sims, cabinets, tubes, etc. We learned we really like compression, at least a little, and especially professionally done, recordings. The history, development, and understanding of compression, over the years, is a good lesson. (explains the "loudness wars").... (I had a 234. Go Tascam!) (...has anyone said u look a bit like Sir Paul?....)

[MichaelBeeny]

Dolby B worked OK on a brand-new cassette deck. New, clean heads, everything in perfect calibration. After quite a short time, the heads ware, get dirty, different brands of tape, what do you get. -6dB @ 5 k So people turned it off. So now it still has no HF but lots of noise.
dbx in domestic form was a joke. The range was far too high. You could hear it working. Try recording a low level piano, you could hear the noise level mixed with the piano harmonics mixing together. Sounded dreadful. Ohh I almost forgotten the very audible pumping effect.
The biggest issue with Dolby B and C was that if worked well on a new deck when recorded and played back on the same deck but when tapes were played on another deck, the Dolby system NEVER tracked the same.
Add differences in tape bias, azimuth, levels and it seldom sounded good. Prerecorded cassettes with Dolby B always sounded very lacking in HF.

[djogoku]

My projector gives the option of Surround SWS3D, DBX and DBX2. Which is best to use?

[octopuscorsica]

Interesting topic. I run my cassette decks through an external hardware denoiser, a Behringer SNR 2000. Unlike Dolby and DBX, this is a single-ended system so there is nothing encoded on the tape itself. The result is quite impressive and I wouldn't go without the device anymore. Would be interesting if you could cover this type of single-ended noise reduction systems.

[redrobbosworkshop]

Always preferred Dolby B if used which was the least intrusive. However, my choice of cassette decks back in the 80s was JVC which used their own proprietary system, ANRS. Basically a clone of Dolby B but has a 'super' ANRS option which introduced HF compression and expansion similar to the later type C and S. However it suffered from horrible modulation noise.
I still have a good collection of decks today and like to record to tape occasionally but my choice is to run a nice 3 head machine using pure chrome tape without NR. yes the noise floor is a bit high but no intermodulation and pumping issues.

[graemejwsmith]

dbx is interesting because it can still "improve" the dynamic range of some vinyl - even though it was not recorded with the encoding. And some - where the frequencies recorded don't fit "the model" it doesn't do anything meaningful for - or even "shifts" the frequency levels around in unintended ways.

[editingsecrets]

Channel content suggestion: You lived through the transition from home recording being rare, expensive, difficult to get right, occasionally spectacular, up to today when tossing it all into a laptop DAW at home is routine.
I'd be interested in your analysis of the production used for things like Face Value, Boston's albums, etc. that were super high end home recording for the time which was transferred to a big format for major label release. The fact that they were done at home either totally hidden or part of a gee whiz marketing campaign.
Leaving out rented mansions, Bob Dylan, Bruce Springsteen, Phil Keaggy, Timbuk3 among those who mentioned that parts recorded at home made it to the final record when this was exotic.

I'm not including Prince, Glen Ballard (for Alanis), Peter Gabriel, Vangelis, or Enya since they had fully pro level studios where they lived.
Now, nobody thinks it's that unusual that Selena Gomez sang in Charlie Puth's closet for "We don't talk any more."
Some of the greatest rock music could never have happened at home, like Bowie's "Heroes, " Thriller, Appetite for Destruction, Faith, Hysteria, Escape, Songs from the Big Chair. No bedroom or living room setup could have made those possible in the 80s.
How much great music has been lost without the use of a dedicated work space and team to support with arrangements, gear, coffee or tea right there.

[Chunksville]

The pumping breathing effect on DBX was annoying especially on quick quiet to loud passages on recordings because of this I would question the relevance of the stated achievable dynamic range.

[sam_]

A video on Dolby HX Pro would be nice too

[RobertWilliams-kwdl]

I'm interested to learn more about the unwanted effects of using dbx on prosumer muktitrack tape recorders such as Fostex B, E, G18, Tascam recorders.

[GeirBakkenVestfold]

This reminds me of when I had Sanyo Super D noice reduction system. It was perfect for copying CD's. No noise and excellent dynamics the 5 first times i played back on my casettes. Then dynamics started too fall apart too quickly for my taste.

[Seiskid]

Dolby - C and S. Your thoughts on how well they both perform on WELL CALIBRATED recordings. Dolby-C is interesting because it has the anti saturation feature it applies to strong high frequency signals - but this also leads to significant mistracking if there's the slightest calibration error. Get it right and to my ears it sounds amazing, but interested in your experience.

[peters]

In the early 1980s we toured a 3 screen video projection music/video album called “TV Fetish” by Question-mark Productions. Using a pair of synchronised high-band Umatic video recorders and a 2kW Turbosound PA.
The audio was recorded on the Umatic’s stereo analogue tracks using DBX noise reduction (can’t remember if I or II) it sounded very impressive, that said a lot of care was taken pre-equing & level setting the audio recorded to ensure optimum DBX decoding.

[SO_DIGITAL]

How about DNR, Dynamic Noise Reduction? LM1894 DNR System. Any good?

[martineyles]

Psychoacoustics in noise reduction. What noise reduction shares in common with lossy compression. I got a glimpse that they might have more in common than we realise, but I think there is probably much more than I realised. Also, does dolby C help give you more treble on non-metal tape. I read something about an anti saturation network but didn't really get it entirely.

[markcolegrove]

I had a dbx II 122 when I was in college paired with a Teac cassette desk. The noise reduction was amazing but you could hear some "pumping/breathing" effects with some music. I assume the compression and expansion circuits were not a perfect mirror image of each other and that was the result. Did this plague the professional gear as well or was this just an artifact on the consumer grade stuff? And... if my diagnosis accurate or are there other reasons for the issues I heard?

[jetphone]

Does Dolby SR actually fight against the principle of saturation?