dbx 1BX III Dynamic Range Expander

skrol

Anyone have experience with a dbx dynamic range expander? I remember these things were well talked of back in the day. I am borrowing one fom a friend and playing around with it. I downloaded the users manual but so far I haven't really found positive benefit for music listening with CD or streaming. It does change the sound but I have not found it to be for the better. Maybe it works better for tape? Am I missing something?

I can see where they could be beneficial in a recording studio or live sound.

VR3

Basically boosts the highs and bass, in a nutshell

Marketing sounds fancier but the truth is that simple sentence above

treitz3

IMO/IME, it's a gimmick.

Tom

motorstereo

Dynamic expanders help a great deal on compressed formats like cassettes, fm radio and vinyl. They're not needed for cd's and make them sound worse.

mhardy6647

The dbx system is (was) a compander (like Dolby NR) and, as such, is a good tool for noise reduction/dynamic range enhancement for noisy sources of limited dynamic range (records, analog audio tape, commercial FM radio). EDIT: These boxes are just dynamic range expanders; not companders. Derp. Sorry.
The 1bx was a single-band (edit) expander, if memory serves(?? -as usual, I am too lazy to check!). The 3bx had three bands (again, if memory serves).

This being said, dbx was made for sources with way less dynamic range than modern digital sources are capable of. Not sure it would do anything but harm for the analog output of digital sources.

mhardy6647

Yeah, I went back & checked. 1bx = one band; 3bx = three band.
https://www.hifiengine.com/manual_library/dbx.shtml

Far from gimmicks, but they were designed for a very different world of signal sources and quality.
There are also potential unpleasant artifacts ("pumping" being perhaps the most salient) associated with poorly adjusted/implemented dynamic range processing. Those of us who grew up listening to popular FM radio stations are more than passingly acquainted with some of those artifacts.

mhardy6647

https://worldradiohistory.com/Archive-All-Audio/Archive-HiFI-Stereo/70s/HiFi-Stereo-Review-1979-07.pdf



https://worldradiohistory.com/hd2/IDX-Audio/Archive-Audio-IDX/IDX/80s/Audio-1980-02-OCR-Page-0031.pdf#search="dbx 1bx"

jdjohn

How about this dbx 228 (bottom unit) I found in my dad's collection?

The top box is basically for input controls...I think.

I hooked these up in a processing loop (of sorts) with a RTR tape deck, and IMO, it improved the sound a bit...with a little tweaking of the 'expansion' slider. The best setting almost seemed to change with every track. These units are available for sale. PM me if interested. I have a feeling they will end-up on eBay at some point.

skipshot12

Back in the day these are what we used to lower noise & increase dynamic range.
Worked great with the formats of the day, as above mentioned, lp’s, tape & also tuners.

Versions I personally used were from phase linear.
Couldn’t afford dbx in those days.
Was getting sound from my lp’s & 45’s that were great.

Cd’s, SACD’s, DVD-A & the rest are no longer in need of the technology.

I still use my phase linear 1000 series II when I play my lp’s 👍

treitz3

mhardy6647 wrote: »

Far from gimmicks, but they were designed for a very different world of signal sources and quality.

Yeah, I know. I (as well as many others) grew up with dbx. I always thought it was a gimmick. It rarely actually enhanced the sound (for me) and at the time? I seem to remember that I got better results with my EQ's. This was before the introduction of this new fandangled little shiny, small plastic disc that sounded like **** at the time. Talk about ear piercing.....

I do know that I tried it many times and it never seemed to last very long before I defeated/bypassed it.

One caveat - I never did try a stand alone unit. Mine was in the various cassette decks that I had at the time, so there may be a big difference there. I seem to remember one deck in particular had a bunch of options with the dbx as well. It's been so long ago, I have no clue what company(s) or even what deck(s). All I remember was the one with many options was a single deck player and it had a black faceplate.

Tom

mhardy6647

yeah -- dbx and cassette not a match made in heaven, although, in theory, it should have done much to level the low-speed, narrow track cassette tape format's playing field with... you know... real tape.

I've had a couple of Technics' dbx-equipped cassette decks, but not terribly good ones, so I don't have anything terribly insightful to say about them. This one (at least) could decode dbx-encoded LPs, which may have been interesting (??).



The issue -- just as with Dolby B -- is the cure worse than the disease?

skipshot12

^ The issue -- just as with Dolby B -- is the cure worse than the disease?

I agree with this...
There were some recordings that didn't do well with the expander & noise reduction.
Was definitely hit and miss. Luckily it was more hits than misses.

When it was right it was awesome.

skrol

Maybe I'll try it again with tape instead of CD and see what it does.

mhardy6647

skrol wrote: »

Maybe I'll try it again with tape instead of CD and see what it does.

couldn't hoit!

SIHAB

I have exactly one DBX record;


Would be interesting to try it...

skipshot12

Never heard a dbx encoded Lp.
Interesting….

skipshot12

skrol wrote: »

Maybe I'll try it again with tape instead of CD and see what it does.

Excellent.
If you have the ability to put it in and out in real time it’ll be a good comparison.


Report back your findings & thoughts.

skrol

It has a bypass that makes it easy to compare.