vkr@osupyr.mast.ohio-state.edu (Vidhyanath K. Rao) (10/31/88)
In article <sXOYA5y00VA-QF=EwO@andrew.cmu.edu> cb29+@andrew.cmu.edu (Chad Kavanaugh Bisk) writes: >[...] The 16-bit, 44.1 KHz D/A chips are useful not for playback of a voice >message or anything else that you recorded on a NeXT machine, but for sound >synthesis and digital playback at the de facto digital standard level (e.g. >Compact Disc).[...] Now if do some recording in the field [no I am not a musicologist but just suppose] my instrument of choice would be a digital audio tape recorder. Will I be able to prodess it digitally using a NeXT?
bob@allosaur.cis.ohio-state.edu (Bob Sutterfield) (11/01/88)
In article <sXOYA5y00VA-QF=EwO@andrew.cmu.edu> cb29+@andrew.cmu.edu (Chad Kavanaugh Bisk) writes: >2) There is only one speaker provided in the NeXT system so playback >at the machine can only be in mono... Note that the sound demos heard >at the announcement ceremonies and elsewhere were piped through the >stereo RCA jacks into external speakers, not through the internal >NeXT speaker. When a student walks up to the system, she first inserts her floptical disc into the drive on her system, then logs in. While (briefly) awaiting the window system's initialization from her dot-files, she dons the lapel mike and shifts her headphone plug from the WalkPerson in her bookbag to the jack on her workstation. While she misses the Talking Heads, at least she's wired into the rest of the world. >...When hooked up to a fast network via NFS, any NeXT machine capable >of voice mail (i.e. having a microphone or an operator headset) will >also be capable of real live 2-way packet-switched voice >conversations. This would require writing some software and would >load down the net, but the advantage of real time communication in a >networked environment is incredible. I can imagine some cooperative talkd(8)s that can adaptively negotiate, between all the machines on a network, the audio sampling frequency in use by each of them. Residents of a more heavily loaded subnet would experience somewhat degraded sound quality as all the talkd(8)s agree to conserve net bandwidth. Network router hop counts would also be a factor. She mouses over and picks the telephone icon off-hook, to place a call to her instructor. Drat, she gets his answering machine - it seems he's off to a conference somewhere, and will check in occasionally from the NeXTs in the show hall. Now, rather than demonstrating the bug in her project interactively, she'll have top drop some animated voice-mail in his box. It seems rather archaic to have to work with him in this sort of non-interactive, batchy sort of way, but it will have to do for now. I wonder what high-latency long-haul networks would do to a conversation's legibility? When I'm tty-talk(1)ing with someone across several IMPs, it gets bursty for both of us. What is the aural analog of packet burstiness? I've experienced long-distance telephony which was apparently passing through a sattelite, and the delays confused all the normal social cues for "Who's talking now?", "Who's waiting for an answer?", and "Did I interrupt?" quite noticably. -=- Zippy sez, --Bob Everybody is going somewhere!! It's probably a garage sale or a disaster Movie!!
jtn@potomac.ads.com (John T. Nelson) (11/01/88)
> Now if do some recording in the field [no I am not a musicologist but just > suppose] my instrument of choice would be a digital audio tape recorder. > Will I be able to prodess it digitally using a NeXT? Depends. Some DATs can do three speeds (32 Khz a Eropepan radio standard, 44.1 Khz the CD player standard and 48 Khz which is the DAT standard). You could take the digital output of the DAT at the 44.1 Khz rate and pump it into the NeXT with some kind of clocking circuitry I suppose but then I'm not a hardware guy so I don't know. Could this go in through a serial port? -- John T. Nelson UUCP: sun!sundc!potomac!jtn Advanced Decision Systems Internet: jtn@potomac.ads.com 1500 Wilson Blvd #512; Arlington, VA 22209-2401 (703) 243-1611 Shar and Enjoy!
postmaster@mailcom.FIDONET.ORG (Bernard Aboba) (11/02/88)
I am afraid that I do not understand the usefulness of putting a CODEC on the motherboard of a workstation, without also putting the other circuitry needed to do voicemail on there as well. Right now, I can buy for $200-300 a card for an IBM PC that will do REAL voice mail, in the background. Two that come to mind are BIGMOUTH, and the COMPLETE ANSWERING MACHINE. There are at least 5 others. What the cards and software do NOT do, is notify someone by ELECTRONIC MAIL over the network that they have a voice message available on the voice server. With the current NeXT hardware, I believe that you will still need an additional card to implement voicemail, which given the cost of design, etc. will probably come to at least $200-$300, negating any advantage of putting the CODEC on the motherboard. The big advantage of putting the CODEC on the motherboard, is I suppose the ability to have a voice message delivered to another workstation, input via a microphone. However, this eats up network bandwidth like crazy, and makes very little sense when an electronic mail message would be much more efficient in terms of bandwidth, and probably more understandable as well. By the way, via use of software like CARBON COPY, you can check for voice messages on a voice serving IBM PC without calling it. -- ------------------------------------------------------------------------------ FidoNet: 1:204/444 UUCP: ...!sun!sunncal!mailcom!bernard INTERNET: f444.n204.z1.Fidonet.org US MAIL: Bernard Aboba, 101 First St. #224, Los Altos, CA 94022
brown@hpccc.HP.COM (Jeffrey L. Brown) (11/03/88)
And now for something completely different (and, I'm sure that no one cares about :-).... / hpccc:comp.sys.next / cb29+@andrew.cmu.edu (Chad Kavanaugh Bisk) / 3:15 pm Oct 29, 1988 / The decisions NeXT made regarding their sound chips and overall sound quality seem quite understandable. My reasoning is as follows: ... 4) The 8-bit codec (just what is "codec" short for anyway?) is plenty powerful ... -- Chad Bisk -- cb29@andrew.cmu.edu ---------- codec: coder-decoder, converts analog signals into digital codes for transmission and then converts back to analog. Sort of like an "inverse modem." Now back to our regularly scheduled programming. Jeff "Hey, that networking class finally paid off" Brown HP Corporate Computing Center brown%hpccc@hplabs.hp.com
arenberg@trwrb.UUCP (Jeff Arenberg) (11/04/88)
In article <361.236F0D6C@mailcom.FIDONET.ORG> postmaster@mailcom.FIDONET.ORG (Bernard Aboba) writes: >The big advantage of putting the CODEC on the motherboard, is I suppose >the ability to have a voice message delivered to another workstation, >input via a microphone. However, this eats up network bandwidth like >crazy, and makes very little sense when an electronic mail message would I'm curious why so many posters have problems with real time voice communications over the network. As I understand it, the system uses an 8 bit mu-law encoding method, sampled at 8 kHz. This translates to a maximum of 64 kbps for each transmitter. On a standard ethernet at say 5 mbps you could have about 39 simultaneous two way conversations. Of course, this would take up the whole net bandwidth, but you shouldn't assume that everyone will talk at once. Also, you can certainly get away with a 4 bit mu-law at 4 kHz sampling without lossing too much understandability and get four times more conversations in, if you are really desperate. For those who wish to know, in the mu-law method the data sent represents some logrithmically scaled change in the current output level, rather than using the data as an absolute value of output level. This allows for a significantly greater dynamic range, but limits the ability to accurately track fast, large changes in sound level. Jeff Arenberg ------------------------------------------------------------- UUCP : ( ucbvax, uscvax ) !trwrb!csed-pyramid!arenberg GEnie: shifty -------------------------------------------------------------
wagner@procase.UUCP (Mark Wagner) (11/12/88)
>> 4) The 8-bit codec (just what is "codec" short for anyway?)
COder DECoder
--
Mark Wagner, ProCASE Corporation. 408-727-0714
...!tolerant!procase!wagner