wjm@whuxk.UUCP (08/31/83)
I'd suspect that the dbx unit on Charles Francois' Teac machine may have been
out of adjustment. I've never noticed any "breathing" on either dbx encoded
disks of piano and harp music (both of which would show it up) - most of the
disks I have were released by Klavier or by dbx tape dubs of LP's. I'm using
an outboard dbx 224 before my Nak 680ZX (with no noise reduction on the Nak)
and generally use Maxell tape (XL-IIS and MX metal for hyper-critical recordings)
Generally, as I've said before, I think dbx is the greatest thing since sliced
bread for noise reduction. dbx disks are interesting, since they are fairly
immune to scratches and surface noise. One of the Klavier piano recordings
I have came with a rather severe scratch on it - if this had been a conventional
recording, I would have taken it back immediately, but with dbx it is, frankly,
inaudible. They are the closest thing to CD's in the analog LP medium.
The only drawback is that there are very few titles released in this form.
Given Teac's reputation (frankly, I regard them as #3 in tape decks after
Nakamichi and Revox, in that order) I'm surprised at the problem. The behavior
that "Stereo Review" found on the Z-6000 is more typical of what I'd expect
from Teac.
Bill Mitchell
Bell Laboratories, Whippany, NJ
(whuxk!wjm)
disclaimer, these are my personal opinions and not necessarily those of my
employer, Bell Laboratories.shauns@tekcad.UUCP (09/02/83)
#R:whuxk:-27000:tekcad:9600010:000:1 tekcad!shauns Sep 1 08:27:00 1983
shauns@tekcad.UUCP (09/02/83)
#R:whuxk:-27000:tekcad:9600011:000:1247
tekcad!shauns Sep 1 08:57:00 1983
Yes, you're quite right, breathing WON'T show up on dbx encoded LPs because the
source noise level is so low. I have a couple and the reproduction (harp) is
flawless. But Mr. Francois is talking about duping NORMAL LPs to tape through
a dbx compander, which is a different case entirely. Here the signal level is
much closer to the noise floor, and breathing is almost inevitable.
Mr. Francois' unit was not misadjusted, since my recently recalibrated 228 will
do and always has done exactly the same thing on certain program material.
I agree with Mr. Mitchell, however - dbx is the best thing since sliced bread
for tape recording live music in particular and LP duping in general. It
offers the recordist many more options and higher performance than Dolby with
far less sensitivity to deck-to-deck calibration errors.
Unfortunately, given the poor quality of even the best non_encoded LPs,
Dolby C may be a better practical solution to tape deck NR when recording
critical material (piano, harp, etc.) from this source.
(An aside: this may be why Nakamichi has never jumped on the dbx bandwagon.)
Shaun Simpkins
uucp: {ucbvax,decvax,chico,pur-ee,cbosg,ihnss}!teklabs!tekcad!shauns
CSnet: shauns@tek
ARPAnet:shauns.tek@rand-relayskittles@inuxe.UUCP (09/02/83)
The recent articles that claim dbx has breathing side effects are wrong. I have been using the dbx 224 for years and have never experienced such problems. Futhermore, in addition to the compression techniques used, dbx II also uses a slight amount of frequency pre-emphasis during recording and the appropriate de-emphasis upon playback. This is much like dolby B and C and it is used to prevent the exact problem the net has been discussing. Also, it is broad band across the entire frequency spectrum. Excuse me for being so bold, but I have a hard time believing that these dbx units are failing. In my opinion, something else is to blame or needs adjusted, especially when considering the Teac cassette deck. For reel to reel applications, >30db signal to noise improvement can be obtained dropping to >20db for cassette applications. This is assuming that dbx II is being used. The second generation circuitry has been around since the mid seventies.
ken@rocksvax.UUCP (Ken Cadogan) (04/03/85)
I am thinking of including a DBX (4BX) in my audio
system.I would like to hear from owners of this product
as to its justification in their system.In other words,
is it worth its capabilities in dollars?I would also
welcome comments from the HiFi public in general.
Ken.