What's wrong with dbx?

If dbx noise reduction can give a cassette deck 90 decibels of dynamic range and signal-to-noise ratio, what's not to like? A lot actually.

CREDITS
Nagra E - Karim Omran, used with permission
dbx 122 - Probably a dbx publicity photo
Revox A77 - s_p_a_c_e_m_a_n from Nottinghamshire, United Kingdom CC BY 2.0
Akai 4000DS - Probably an Akai publicity photo
Tascam Portastudio 244 - CountrySkyStudio CC BY-SA 4.0
Roland TR-606 - Mi das Wouters CC BY-SA 3.0
Casiotone 1000P (it might have been this model) - Salvador Calyso CC BY-SAL 4.0
Fender Stratocaster (similar to this image) - Fender_Stratocaster_004.JPG: Stra2casterderivative work: Atlantictire, Public domain
Music - 'The Last Days Of September' by David Mellor, All Rights Reserved

[jimrogers]

I worked in a recording studio in the 80s and early 90s that did a LOT of ad work. We used dbx NR on all of our production 2 tracks (for the ad tapes) and had Dolby A units for our music 2 tracks and multi tracks. dbx was good if you kept it in house, as I kept the 2 tracks aligned every day. However, taking any dbx masters out of the studio, into another studio, there was a decent amount of pumping and breathing that our "friendly competitor" would complain about.

We did a double blind noise reduction shootout that I used to write an article for R/EP. The systems compared were dbx, Dolby A, Dolby SR, and Telcom C4. For me, the clear winner was Telcom C4, a system that was developed in Europe because the engineer who developed it wanted a Dolby A system, but couldn't afford it. One of our in-house engineers thought he had golden ears. In the playback, he said that Dolby SR was dbx... so much for his golden ears.

Remember, cassette was a format that was originally designed for dictation only, but somehow it was able to reproduce music with better than reasonable fidelity... I have cassettes that are more than 30 years old that sound great. BASF did a series of lab studies and found that 90% of the signal degradation took place within a very short time. In some ways, I wish that we still had cassettes instead of CDs because cassettes were a known quantity. Phillips took in a small licensing fee for EVERY EMPTY CASSETTE SHELL MANUFACTURED AND SOLD!! Although the fee was small, with the millions of cassettes made every year, it was quite an income for them.

I worked for a high speed cassette duplicator for a few years back in the early 90s... what a trip that was. If you kept the systems maintained (which was EASY to do) you could turn out a very high quality product... and they didn't skip like CDs can.

Sorry for the rambling, but this video brought back a LOT of memories. Cheers!

[JohnnyJuleJazz]

I had a Tascam Porta Studio too. The same model!!! I have been a drummer most of my life and I am now 66 years old. I have quite a home studio now, optimized for drums of course.

[DavidMorley]

I use DBX on my Tascam 388. People love to hit tape hard but in my experience if you record with conservative levels and DBX (as they recommend) it works extremely well on most stuff. No noise and few side effects. So if used properly and carefully, it can be excellent. But I don't do solo piano! Subscribed!

[JohnSmith-pqvn]

Reading all the comments leaves me thinking I must be living in a parallel universe. I use dbx all the time and love it. I have several 224x units that I use mainly with my cr7e or whatever other deck I choose to swap in. I must be deaf as I have never encountered any pumping or breathing artifacts, and that is with any type of music, folk, rock, pop etc. I push my levels hard and find that I can swap decks for playback with no issues. My Onkyo Ta 2900 or Technics RS B965 with built in dbx also have no issues with tapes recorded with dbx on other decks. Compatibility these days I find not so much of an issue, as it's really only me who will be listening to my recordings on my units. The only slight difference I find is a very slight loss of high end treble on the recordings, easily compensated for with a tiny tweak of the treble knob on my amp. As someone else quoted, "silence has more noise that dbx". OK a slight push, but I love cassettes, hate intrusive hiss so adore dbx. Yes I also love digital and streaming. I'm not someone who thinks digital is soulless, but no way I'm I consigning all theses beautiful vintage cassette decks to the dump. They were designed and manufactured in an age when tech companies took pride in what they made and were clearly competing to be the best. No money to be made now in these things, so that is all a thing of the past. Wait and see how your new tech stands the test of time.

[steve]

I used dbx a lot with cassette. At the time, I was in the organ business and listened to a lot of organ music. The combination of huge dynamic range and slow volume changes made dbx ideal here.

[lenimbery]

I always thought that people left the Dolby B switch off on playback because it left the extra bright sound which people equated with a more pleasing sound. You give great explanations to all things audio. Thank you

[soundonsound]

Thanks for the magazine plug, David. 🙏👍

[nikolaki]

Getting me all nostalgic again over my Proton 740 cassette deck! Factory calibrated to XL-IS and XL-II-S tape. Recordings on the latter were awesome. B, C and dbx.

The dbx on it was revelational. Great for rock, pop and most jazz. Not great for solo piano.

It was the only way I got to hear a dbx vinyl I bought. Jaw dropping back in the 80s.

[djohnson]

I own a Luxman cassette deck, which I mostly used during the '80s and '90s. With high-quality chrome and metal tapes, I always found slight to moderate increase in bias improved record fidelity. And I also liked to introduce just a bit of saturation by finding the absolute peak signal volume of the entire song and adjusting the record gain to peak at 100% and with some content slightly above. I did not perceive hideous noise. And when played in the car or through my buddies' high-fi's I had the best sounding mix-tapes, by far. (Having the best sounding mix-tapes you could share with friends was important back then! You, certainly, already know this.) As for the Dolby B and C, those sounded great played back through my own system, but hit-or-miss results elsewhere - mostly miss. Have we covered tape AC bias in Audio Masterclass? Enjoy your videos, very much! Your Tascam PS recording with dbx sounds fantastic! Love tape.

[MrSlipstreem]

Thanks for the explanation of how Dolby B did actually work well on a correctly calibrated and maintained cassette deck. Many of the decks I've bought in the past weren't even calibrated correctly straight from the factory, so it's not hard to understand how Dolby B got such a poor reputation in folk lore. It performed transparently (as far as my ears could tell) once properly calibrated, particularly if I stuck to the brand and flavour of cassette I'd calibrated it to.

I designed and built my own stereo DBX (I refuse to use lowercase) system some time around 1990 using a pair of NE571 ICs to use with a hi-fi cassette deck. The electronics had a dynamic range of around 110dB and a frequency response flat to within 0.2dB from 20Hz to 20kHz, so performance was actually pretty good. As you say, the pumping noise effect from a cassette deck that only had a signal-to-noise ratio of around 56dB was completely unbearable.

Using it in combination with a correctly calibrated Dolby B improved it significantly, but it was still audible. I tried it in combination with Dolby C a few years later and the problem all but disappeared giving a noise floor down around -100dB using a TDK D cassette tape. I didn't use it in the end as it would have made my recordings incompatible for anyone else to listen to, but it was still a fun exercise in what could be achieved with a budget tape and a ~£20 project.

[ScottGrammer]

Compander noise reduction systems are often thrown for a loop by the nonlinearities of the tape decks involved. And the more noise reduction they aim for, the more problems they have. It's possible to align, say, Dolby B to be nearly transparent when a tape is played back on the same machine it was recorded on, but usually not when recording on one machine to play back on another. Today, working as a vintage audio service tech, I tend to align Dolby systems for best subjective results, not the best measurements, and my clients are usually amazed with the results. Of course, this is after aligning the tape deck in the usual manner without noise reduction.

In the early 80's, I engineered in a home studio that used a Teac 80-8 multitrack machine with its associated dbx noise reduction box. I quickly learned that even when I had the machine carefully aligned, it was better to record drum tracks with the dbx turned off. It just could not follow the transients of say, a snare drum by itself. It seemed that dbx did much better with a full mix, and definitely did better with continuous midrange tones, like strings or backup singers. Didn't work well on bass guitar, either.

[nicc]

The effectiveness of dbx did also depend on the material being recorded. Today's compressed pop that you've covered would be ideal for dbx on a cassette. You can't unhear the breathing or pumping effect for some material, but it does come down to are you listening to the music itself or listening to what's wrong with the recording and replay process. Some of my vinyl collection I have heard tape dropouts. I've heard the same in some CD re-releases. It doesn't stop me enjoying what I'm listening to.

[Mrsteve]

I never could get past the "breathing" or "pumping" effect of dbx. Once heard, it's inescapable in subsequent listening. To me, Dolby S is among the best noise reduction (with HX Pro assisting), however it came to the game much too late to be of any real impact in the cassette deck market.

[ReasonablySane]

I still have a dozen or so dbx vinyl records as well as a matching DBX decoder. They were a nice stop gap before CDs came out.

[Rich-hk]

Thanks for the video, I know this is an older one but I figured I’d chime in anyway.

I use a dbx 224 (all lowercase haha) outboard unit, and I think the trick to getting no modulation as you say, or pumping or breathing sounds is to record at the proper levels, and I will add that I record a decent chrome tape with peaks at 0 to + 2 dB but no higher. I also use it with HX Pro (caps allowed) with great results. In fact it sounds so close to the source that I doubt anyone would ever know that it’s a cassette playing. I think dbx needs to be used on a quality deck, because everything that’s wrong before the processing gets amplified double. These are my experiences anyway. Thanks again.

[shiznitmufu]

Love the recording. The quintessential portrait of the foundation of the decades long, and ongoing, evolution of home studio development. @ 54 yrs of age, many things have escaped the grasp of my memories.However, carved in granite are recollections of sitting in front my Grandmother's beloved floor model RCA, AM/FM/8 Track/Phono console, clutching her Panasonic portable MONO cassette recorder, impatiently waiting for the distant FM rock n roll radio station to play my favorite tunes.With a fresh set of C cell Rayovacs and a crisp new Memorex or TDK blank cassette tape loaded
(Rec.+Play+Pause)and on the ready, I captured many hours of my guitar heroes and they, in essence became my guitar instructors.Nearly hAlf century later, with EVH, SRV, Hendrix, Rhoades, Clapton and Dimebag Darrell's stolen licks, leads and tones oozing from my fingers and broadcastimg from my vintage Fender Sratocastor and vintage Fender Tweed tube amp, I'm still amused by the look on my 4 sons(all grown and musicians) faces when they repeat in unison as I'm still proclaiming, "Son, back in my day we didn't need WiFi.WE HAD HI-FI!! Love the channel. I've learned so much.Thank you.🙏. 🤘🏻🤘🏻

[scottwolf]

In 1975 bought the dbx 119, for my Teac 360 cassette deck. A totally discrete, separate enclosure, model with adjustable gain and, "Compander", pots. So the compression and expansion varied from 1:1 to 2:1. There may have been an Infinity setting too. I still have the pamphlet somewhere but sold the unit decades ago. The auditory, " Breathing", introduced made the use unfeasible.

[MichaelBeeny]

A long time ago in a land far from here (NZ) NEAL made cassette decks. But, did you know that they also made a high-speed version?? Yes they did, we used to sell them. It ran a 3.75ips and was the best sound EVER from a cassette deck. Almost flat up to 18khz not 10dB down like most decks. Sadly, they were quite hard to sell. Everyone agreed the sound was near 100% but you could not change the speed to play normal cassettes. Of course, you needed a C120 to get 60 minutes of play time. This arrangement was short lived however as it contravened the license agreement of Philips.
Just imagine if cassette decks had all been 2 speed, one speed for the sound deaf and one speed for the sound enthusiast. Now that would have given cassettes a real boost in sales.

[thechuckster]

DBX is king! If you align the machine and the DBX correctly, the results are stunning!

[richiereyn]

I've never used dbx noise reduction with cassettes. dbx type II was developed for cassettes but also open reel machines running at 7.5 and 3.75ips, so type II was always considered the domestic version of dbx. Type I was used mostly on open reel recorders running at 15ips, though you could get good results at 7.5ips if the machine was electronically and mechanically aligned correctly. At 15ips, type I was a revelation. I could never really notice any noise pumping issues, but the criteria was always flatness of frequency response and a properly aligned machine. If you could hear obvious noise issues with dbx on an open reel at 15ips, usually the problem was the machine, not the noise reduction unit.