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Beechwoods
26-10-2009, 19:51
On a bit of whim I decided to get myself a dbx 224 noise reduction unit. From what I've read dbx did ok in the professional market, but lost out in the domestic market due to the fact that dbx encoded material sounded terrible on non-dbx capable equipment, whereas Dolby, which implemented a milder approach to compression, sounded OK when played back on non-Dolby gear.

I'm looking forward to seeing how my unit performs. I'm also interested in getting hold of a few dbx encoded vinyl LP's - Pink Floyd's 'Atom Heart Mother' was released in dbx, which I'd be keen to hear. It'd be interesting to see if other members here recall any interesting dbx encoded LP's that I should keep an eye out for.

Has anyone had any experience of dbx? Anyone use it in their setups or have tapes from ye olden days encoded with dbx? I'd be interested to hear from you if you have!

http://i560.photobucket.com/albums/ss49/aos_images/beechwoods/22-222-224_II.jpg

DSJR
26-10-2009, 20:01
The original DBX could make background noise "pump" if not used correctly. I think it's a bit like surround-sound. Overdo it and the effect is awful. Use it with discretion and sensitivity and I'm sure it's great...

Spectral Morn
26-10-2009, 20:07
Hi Nick

I have looked at a few of these too, on the Bay. However the common issue seems to be breathing noises (that what its been called). Its apparently an artifact of the decoding. The main reel to reel I have now is a Dolby B model late Revox A77 mk4. I have yet to do a comparison between the non Dolby B77 and A77 Dolby or not (will all be part of a future write up).

The other thing I had read is about the machine (R to R) being/needing to be calibrated to an external noise reduction unit. Not sure about that or how you go about it. I suspect that Alex Nitkin will be the guy to tell us whats what.

Regards D S D L

Beechwoods
26-10-2009, 20:18
I'm obviously only going by what I've read so far but dbx is supposed to have a wider 'operational tolerance' than Dolby, which was calibrated to work within tighter tolerances (recording levels) than dbx. Breathing is definitely a consequence of incorrect decoding (or no decoding at all) which I guess is more likely to occur when material recorded on one setup is played back on another.

According to the manual, certain types of sound - solo basses, solo piano - focussed around the low and mid-frequencies (without masking high-frequencies) tend to be more likely to fail clean compression / decompression. I'll be interested to see what makes the system break as much as what makes it work.

One other thing that affects the performance of dbx is source noise - the self-noise of your turntable or tape deck. To be honest, I don't feel I've got a problem with noise on my sources - I'm 'by birth' a no-NR guy and all my decks are extremely low noise. This being the case I hope that they work well with this outboard unit. Let's see. I will definitely be reporting back :)

I'd be extremely interested to read Alex's take on this subject (and NR in general) if he gets the chance to to read this.

Spectral Morn
26-10-2009, 20:22
The original DBX could make background noise "pump" if not used correctly. I think it's a bit like surround-sound. Overdo it and the effect is awful. Use it with discretion and sensitivity and I'm sure it's great...

Yes I have read about that too "Pumping" as a side effect as well.


Regards D S D L

Tony Moore
26-10-2009, 20:23
I bought a Teac cassette deck back in the early 80s, my first that had DBX. It had both Dolby B and dbx. The dbx was far superior in both noise reduction and adding a far more dynamic sound.

However, as noted, tapes recorded with it could really _not_ be played back on any deck that didn't have dbx as they sounded thin and pumpy. When the tape wore a little the sound did get more "breathy" than when first recorded.

The old Teac is still around but the head is worn and it's not a patch on what it was. I have a Technics deck from the early 90s that has Dolby B & C and dbx so that's ok for playing back my old tapes.

I really liked the old dbx. Better than Dolby C in my opinion.

I wonder if I could get a new head for the Teac?

Cheers,
Tony
ps.

Mine was one of these...

http://cgi.ebay.com/TEAC-V-5RX-Cassette-Deck-With-Dolby-And-Dolby-DBX_W0QQitemZ250515922264QQcmdZViewItemQQimsxZ2009 1018?IMSfp=TL091018134004r12730

Rare Bird
26-10-2009, 22:25
How those DBX recods work is the quiet & loud passages are split up into two, the goal is lower record noise, was a flop from the 80's...i used to have a DBX 2BX unit...had the atom heart DBX issues aswell as the Quadraphonic issue..

REM
27-10-2009, 08:42
Had a Technics dbx cassette deck in the early/mid 80's, great machine but soon learned it was so much better without any N/R. DBX didn't just 'pump' it robbed recordings of any sense of music, strange effect. Without the N/R if you recorded tapes as loudly as possible the average levels masked any tape hiss anyway. Lesson learned.

DSJR
27-10-2009, 13:30
Neil, you call it breathing and I call it pumping. Whatever the description, it's not pleasant.

I have an LP (Fresh Aire ?) which was recorded with what appears DBX. Whenever a piano note is struck, there's a "psssss" noise in the background (only way I can crudely describe it).

As I recall, the best domestic NR system was Dolby S, and apparently the professional Dolby SR gives a whole new lease of life to analogue tape recording...

Amazing when you think of the multitudes of components a music signal passed through from microphone, through a complex mixing desk, Dolby unit (each multi-track), back out again and onto the tape, then back through an unrelated Dolby unit to the cutting head. Makes you wonder how LP's sounded any good at all..............

Spectral Morn
27-10-2009, 13:39
Hi Dave

Just as well Dolby didn't take off for FM radio broadcasts..or any other noise reduction format. The encode decode issues when changing tape/reel to reel machines would have been huge...never mind one station using Dolby and another using DBX.

Must admit I have never heard Dolby S or SR...never having owned such a machine or sold one with it....that I can remember that is.


Regards D S D L

Lodgesound
30-10-2009, 10:03
Hi there;

If you want to turn your tape recorders into something very special try and get hold of a Dolby 363 encode / decode unit with SR cards fitted - Dolby SR adds a dimension to analogue tape recording that you simply won't appreciate unless you hear it and start to use it. At 7.5 ips on a half track stereo machine I get a measured noise floor of -85db using SR - quite exceptional!

DSJR
30-10-2009, 21:27
How much approximately?

Lodgesound
02-11-2009, 08:30
Around 400 - 600 pounds - they come up on ebay quite a bit often with the CAT 300 dual Dolby A / SR encode-decode cards fitted.

Wilbur
16-11-2009, 06:13
Using a 222 with my MkI and mkII ReVox B77's,it takes a little setting up with level presets on the back of the unit but once its done,its done.Used it with my ReVox G36 a while ago,wow..........:smoking:

Kris
05-12-2009, 19:27
I have had a DBX124 gathering dust for the past few years. I want to rewire it and put in new phono sockets though before I plug it in and try it. I have a couple of DBX records, nothing special, but it would be interesting to see what it sounded like.

http://www.thealizone.com/images/dbx124front.jpg


http://www.thealizone.com/images/dbx124back.jpg

Beechwoods
05-12-2009, 19:33
My machine arrived and looks in good nick, but I've not had the time / energy to plumb it in and see how it sounds yet. I really should pull my finger out!

Rare Bird
05-12-2009, 19:56
I have had a DBX124 gathering dust for the past few years. I want to rewire it and put in new phono sockets though before I plug it in and try it. I have a couple of DBX records, nothing special, but it would be interesting to see what it sounded like.

http://www.thealizone.com/images/dbx124front.jpg


http://www.thealizone.com/images/dbx124back.jpg

Kris i used to have that with my '2BX' the NR for the bigger four channel '4BX' was the '144' i think.

Here's a pic i got off the net of the '2BX':

http://i12.photobucket.com/albums/a222/LIVING-SIN/2BX.jpg

They were pretty well made solid teak side cheeks aswell.

Last time i used a DBX unit was about 4 years ago when i had a Teac 'A3440' Open Reel with the 'RX9' 4 channel DBX unit

Another below i nabbed off the net. you can see the 'RX-9' unit under the 'A3440' machine. One of the units channels were down & i couldnt for the life of me fix it..The open reel VU bulbs would sometime blow aswell in which you have to literally take the machine to bits to replace..so i flogged em :mental:

This machine sounded better than the Revox 'B77'..

http://i12.photobucket.com/albums/a222/LIVING-SIN/A3440RX9.jpg

Kris
05-12-2009, 20:16
This machine sounded better than the Revox 'B77'.

Frankly, I think the B77 was overrated. Why it achieved cult status I really don't know. Probably because of its reliability?

It would be interesting sometime to try the DBX on my Open Reel to see what happens. Yes, I must replace the phono sockets sometime.


i used to have that with my '2BX'

Ohhhh . . snap :ner:

http://www.thealizone.com/images/dbx2bx.jpg

Will someone please take this dust fairy off my hands. . . .

Rare Bird
05-12-2009, 21:00
Nice one Kris..