lionel@eiffel.DEC (Steve Lionel) (08/17/85)
Paul Kemp chided me for some inaccuracies in my item about Hi-Fi VCRs.
I don't think I was as far off as Paul thinks.
1. On the item of "forwards and backwards compatibility", I simply meant
that Beta Hi-Fi tapes could be played on non-Hi-Fi units, and
vice versa. What is important here is that Beta Hi-Fi machines also
record the linear mono track, and that the Hi-Fi signal does not confuse
a non-Hi-Fi Beta VCR. Much the same holds for VHS Hi-Fi, by the way,
except for the problems noted later about the stereo tracks.
2. I know enough about AFM recording to know that AFM has nothing to
do with the way that the information is put onto the tape in VHS Hi-Fi.
The "depth multiplexing" works in part because the video signal is
at much higher frequencies than the audio signal, and thus doesn't
penetrate as far into the magnetic coating as does the audio signal.
As I said in my first note, the azimuth angles are also different so
as to minimize interference. The term AFM simply means that the
audio is frequency modulated.
3. Some newer VHS Hi-Fi VCRs, such as Panasonic's latest model 1740,
do NOT play or record the linear track in stereo. I don't understand
this cheapness either, but there it is.
4. As for my comment on JVC coming up with something to match SuperBeta,
and Paul relating JVC's noise reduction techniques, I stand by
my comment. In that item in Video that Paul quoted, it said that
JVC admits that "high-band VHS" (which would be the same technique as
SuperBeta) isn't coming before 1987. The circuit enhancements JVC
is adding does not significantly increase the information in the picture,
but tends to fool you into thinking the picture is sharper - that's
the "white clipping" part. Note that the VHS camp definitely has
said that they don't want these enhancements called "SuperVHS". (Maybe
because it would make it painfully obvious that VHS is always in
a trailing technological position relative to Beta.) As a matter of
interest, several people I know are replacing their VHS decks with
a new SuperBeta - the difference is too real to be ignored.
Steve Lionelpjk@hou2a.UUCP (P.KEMP) (08/19/85)
[Sorry to continue this discussion over the net, but there are some items that are of general interest.] Steve, I'm sorry if I misunderstood some of your statements on VCR AFM recording, but there still appears to be some confusion remaining. In VHS AFM HI-FI recording, the FM modulated audio signals are recorded in a frequency band where there is still substantial video signal energy. That is why "Depth-Multiplexing" is used. The AFM signal penetrates deeper into the tape because the AFM heads have wider gaps than the video heads. The wider gaps do not pose a problem because of the lower frequencies of the AFM carriers. This, along with head azimuth offset, minimizes the interference between the AFM and video signals. I can't believe that the new, top-of-the-line, Panasonic 1740 can't PLAY Dolby stereo linear audio, but Steve is correct! The review of the 1740 in the September issue of VIDEO Magazine states in the last paragraph: > Note: if you want linear-track stereo, buy last > year's models now. Almost all VHS manufacturers > are switching from stereo to a mono linear track. I guess I'll keep my Quasar 5845 VHS HI-FI for awhile. It can both RECORD and PLAY the linear audio tracks in Dolby stereo. As far as "enhanced" VHS from JVC goes, Steve Lionel boasted in his original posting: > Well, that's our history lesson for today. Perhaps in a year or so, we'll > see if JVC MANAGES TO COME UP WITH SOMETHING *APPROXIMATING* Superbeta. From > recent announcements, it doesn't seem that way. Well, I think that "enhanced" VHS from JVC is something approximating SuperBETA. While it doesn't actually increase the video frequency response by much, it does make the picture *appear* sharper. This along with the video noise reduction technique that JVC is now working on, should result in better quality VHS pictures in the future. Does anyone know if tapes recorded with "enhanced" VHS will appear sharper played back with a regular VCR? Since it works as a pre-emphasis, I think it would. I personally feel that the BETA system is technically superior to the VHS system, but unless your video system can exist independent of the outside world (or you happen to have friends and video stores nearby that have BETA), you are better off with VHS because of its overwhelming popularity now. Sony is now the only VCR manufacturer that produces only BETA home VCRs, and they are placing their bets on 8mm as the format of the future. -- Paul Kemp ihnp4!hou2a!pjk
nzm10@amdahl.UUCP (Neal Macklin) (08/23/85)
From Paul Kemp: > I personally feel that the BETA system is technically > superior to the VHS system, but unless your video system > can exist independent of the outside world (or you happen > to have friends and video stores nearby that have BETA), > you are better off with VHS because of its overwhelming > popularity now. Well, that depends on the area. Beta is doing quite well out here, and I've heard of a lot of people who are now buying beta (either hifi or super beta). The video stores seem to have a better selection in beta than vhs, especially on friday nights. I also heard that vhs on slow speed doesn't record hifi well, whereas beta seems to have no problem. I personally would go for quality, because a fuzzy picture would be a constant reminder to me that I had made a mistake [:-)]. I guess you can tell I am not.......Mr. Video. -- Neal Macklin (408) 737-5214 ...{hplabs,ihnp4}!amdahl!nzm10 [There are no opinions expressed in this article].
brown@nicmad.UUCP (08/24/85)
In article <1938@amdahl.UUCP> nzm10@amdahl.UUCP (Neal Macklin) writes: >I guess you can tell I am not.......Mr. Video. Does this mean I am becoming famous or infamous? :-) -- Mr. Video {seismo!uwvax!|!decvax|!ihnp4}!nicmad!brown
nzm10@amdahl.UUCP (Neal Macklin) (08/28/85)
> In article <1938@amdahl.UUCP> nzm10@amdahl.UUCP (Neal Macklin) writes: > >I guess you can tell I am not.......Mr. Video. > > Does this mean I am becoming famous or infamous? :-) > -- > Mr. Video {seismo!uwvax!|!decvax|!ihnp4}!nicmad!brown Famous on the net at least. I personally liked your drawing, even though you made the mistake of buying VHS. Other than that, your comments are usually sanguine!! -- Neal Macklin (408) 737-5214 ...{hplabs,ihnp4}!amdahl!nzm10 [There are no opinions expressed in this article].