wtm@neoucom.UUCP (06/05/87)
Hi, I just heard from some people that got back from the Chicago CES, some of the details of the proposed new standard to be employed for production of source material (compact disc records) and digital audio tape (DAT) machines. From my understanding, what will possibly be done is to master CDs with a narrow band notch set for 3800 Hz as the material is mixed down into final form for the consumer's copy. DAT machines are to be equipped with a so-called spoiler chip that will monitor three narrow bands of 3800-, 3800, and 3800+ Hz. The idea is that if the chip detects energy in the two outer bands and none in the middle band, that it will shut down the recorder, as "obviously" a pirating event would be under way. The question for the net is, just how wide is the missing mateial notch going to be. Supposedly, people that have heard trial recordings of the processed material claim that it is very noticable on things like classical and jazz recordings that feature solo instrument passages more than rock does. Apparently, some notes are curiously dull sounding on piano passages due to the action of the notch filter. Vocals are also apparently affected. The record companies are currently lobbying the US congress to enact legislation that would make the use of the spoiler chip mandatory on DAT machines sold in the US. Columbia Records announced that it is going to start processing all its releases in the next few months to have to 3800 Hz notch. Other record companies have not officailly announced any plans. Marantz plans to begin importing in September of '87, a DAT machine that *will not* have a spoiler circuit. They are operating under the assumption that the legislature won't be able to do anything before then any way. The whole DAT spoiler seems silly to me. The wost thing is that people who do not pirate the material are punished by having to listen to recordings of reduced quality. It would be possible for pirates to go about their business by summing low level hiss with a spectrum centered at 3800 Hz. I suppose that a correlation could be done to see if the amplitude of the 3800 component related to the sidebands, thus preventing hiss injection from spoiling the spoiler, but that sort of DSP would probably be too expensive for consumer equipment. There is something you can do. The recording rights coalition has a phone number, 800-282-TAPE, that you can call to get information about where you can complain about the proposed spoiler legislation. Bill Mayhew Division of Basic Medical Sciences Northeastern Ohio Universities' College of Medicine Rootstown, OH 44272 USA phone: 216-325-2511 (wtm@neoucom.UUCP ...!cbatt!neoucom!wtm)
rbl@nitrex.UUCP (06/07/87)
In article <598@neoucom.UUCP> wtm@neoucom.UUCP (Bill Mayhew) writes: >Hi, > > I just heard from some people that got back from the >Chicago CES, some of the details of the proposed new standard to be >employed for production of source material (compact disc records) >and digital audio tape (DAT) machines. > > From my understanding, what will possibly be done is to >master CDs with a narrow band notch set for 3800 Hz as the material >is mixed down into final form for the consumer's copy. DAT >machines are to be equipped with a so-called spoiler chip that will >monitor three narrow bands of 3800-, 3800, and 3800+ Hz. The idea >is that if the chip detects energy in the two outer bands and none >in the middle band, that it will shut down the recorder, as >"obviously" a pirating event would be under way. > >The question for the net is, just how wide is the missing mateial >notch going to be. Supposedly, people that have heard trial >recordings of the processed material claim that it is very >noticable on things like classical and jazz recordings that feature >solo instrument passages more than rock does. Apparently, some >notes are curiously dull sounding on piano passages due to the >action of the notch filter. Vocals are also apparently affected. > ... >Bill Mayhew >Division of Basic Medical Sciences >Northeastern Ohio Universities' College of Medicine >Rootstown, OH 44272 USA phone: 216-325-2511 >(wtm@neoucom.UUCP ...!cbatt!neoucom!wtm) In the latest issue of MART, a trade magazine for electronics/appliance dealers, an article mentioned that CBS noted that in "some passages" the notching would be eliminated. They interpreted this as CBS admitting that the anti-copy technique would, in at least certain sections of music, corrupt the sound quality. Rob Lake decvax!cwruecmp!nitrex!rbl
dave@sdeggo.UUCP (06/07/87)
In article <598@neoucom.UUCP>, wtm@neoucom.UUCP (Bill Mayhew) writes:
- The whole DAT spoiler seems silly to me. The wost thing is that
- people who do not pirate the material are punished by having to
- listen to recordings of reduced quality. It would be possible for
- pirates to go about their business by summing low level hiss with a
- spectrum centered at 3800 Hz. I suppose that a correlation could
- be done to see if the amplitude of the 3800 component related to
- the sidebands, thus preventing hiss injection from spoiling the
- spoiler, but that sort of DSP would probably be too expensive for
- consumer equipment.
It sounds very silly, especially considering that those of us who buy CD's
are paying a premium for high sound quality. Like any other form of copy
protection, there are sure to be plenty of ways around it, making the only
people truly affected by it the ones who are lawfully paying for it.
Instead of messing about with the audio signal, why not just reach in with
a soldering iron and clippers and tweak the chip out of the circuit, or
make it think that it always has some noise there with a little 3800 HZ
oscillator tied to its input. How much do you want to bet that
Radio-Electronics has an article "for experimental and educational purposes"
on how to do it within a month after they come out?
It's amazing what some clowns will come up with in the name of "protection."
Isn't it enough that they charge a rather ridiculous price for the music,
without dreaming up ways to make it sound bad?
----
David L. Smith
sdcsvax!sdamos!sdeggo!dave, ihnp4!jack!man!sdeggo!dave, hp-sdd!crash!sdeggo!dave
sdeggo!dave@sdamos.ucsd.eduwolfgang@haddock.UUCP (06/08/87)
What would prevent someone from copying a CD by mixing a bit of white noise in with the program material? I would imagine that a very little bit of interstation static from an AM or FM radio would suffice to fill in the bottom of the 3800 hz notch. (I small bit of noise would actually help reduce the distortion caused by digital quanization. It might actually make stuff sound a bit better.) Does anyone know the full details of this CD labotomization scheme? Is it the absolute value of energy at 3800 hz or the ratio of energy at 3800 hz. vs the rest of the spectrum? How much energy must be present at 3800 hz to reset the copy protector? -- Wolfgang Rupprecht haddock.ISC.COM!wolfgang
wtm@neoucom.UUCP (Bill Mayhew) (06/11/87)
In article <67@sdeggo.UUCP>, dave@sdeggo.UUCP (David L. Smith) writes: > .... How much do you want to bet that > Radio-Electronics has an article "for experimental and educational purposes" > on how to do it within a month after they come out? > > It's amazing what some clowns will come up with in the name of "protection." > Isn't it enough that they charge a rather ridiculous price for the music, > without dreaming up ways to make it sound bad? > > David L. Smith I got quite a kick from the R-E article about how to make police radar read out whatever speed value you want by beaming a microwave signal at it imitating the Dopler shift. Obviously such a gadget is only for calibrating you own radar gun (hee hee). I especaially liked the relay input for attaching to your radar detector output to save wear and tear while not calibrating your radar gun. (as if it would be such a phenomenal chore to switch on the calibrator when necessary!) Very charming, indeed. Bill Mayhew NEOUCOM Division of Basic Medical Sciences (wtm@neoucom.UUCCP ...at least for the moment.)
store2@ihuxi.UUCP (06/23/87)
In article <67@sdeggo.UUCP>, dave@sdeggo.UUCP (David L. Smith) writes: > > Instead of messing about with the audio signal, why not just reach in with > a soldering iron and clippers and tweak the chip out of the circuit, or > make it think that it always has some noise there with a little 3800 HZ > oscillator tied to its input. How much do you want to bet that > Radio-Electronics has an article "for experimental and educational purposes" > on how to do it within a month after they come out? > Sorry, but the protection circuit will be buried deep in one of the LSI's. There will be no way to remove it and even if you could, the notch will still be there on the source CD. That is what has everyone so up in arms. Even if you never copy a CD, you will have to listen to the CD with a 200 hz notch in it and some people claim you can hear that it is missing. I don't know. I was at CES but I didn't see any setup with a CD player playing a copy protected disc. I did hear a DAT player. Very impressive! Kit Kimes AT&T--Information Systems Labs ...ihnp4!iwvae!kimes "I'm carrying the weight of all the useless junk a modern man accumulates. I'm a statistic in a system that a civil servant dominates." _Running On Ice_ -Billy Joel
agn@unh.cs.cmu.edu (Andreas Nowatzyk) (06/26/87)
> Sorry, but the protection circuit will be buried deep in one of the LSI's. > There will be no way to remove it and even if you could, the notch will > still be there on the source CD. That is what has everyone so up in arms. It seems very unlikely that the copy-protection circuitry will be burried deep inside. Consider the nature of that chip: several filters, various integrators, gain-control, etc. (The block diagram was recently published in an audio magazin). This can be implemented either as an switched-capacitor device (a) or as a completely digital circuit (a). The process for (a) is incompatible with a controller micro used to control the entire DAT. (b) is fairly complex, requires a more difficult interface to get the digital data stream (that isn't available on the controller: the extra data-path may not live long... :-) and needs a substantial ammount of fast logic. Again, this is different from the usual low speed, low power process that is used for the controller. Besides, both approaches require significant silicon real estate and extra design efford to integrate this gadget in other circuitry (mostly standardized stuff). The larger chip has a lower yield, longer design time and is more difficult to test. The DAT controller (user interface, display, tape counter, remote controll, lots of other boring stuff - but no audio data handling) is a unlikely place for the CP stuff. Similar arguments can be made against placing the CP circuitry in parts of the recorder data-path. Note that there are at least 3 chips involved here: 1) ADC (perhaps with an integrated digital filter), 2) Digital data path (fifo, generation of EDC codes, adding control info, formatting) and 3) Driver (converts the digital data into an analog signal to drive the write head, various servo-loops, etc.) The technology for these essential parts are quite different (1: precision CMOS with some analog capabilities, isolated from the noisy digital power; 2: high performance CMOS; 3: bipolar). In all likelyhood, the CP chips will be extra that listens to the analog input. Either the input or the output are begging to be cut off. Note that Sony (and probably other sources) provide really nice service-manuals with circuit diagrams, PC-board layouts and anything you need to know. For more fun, the control processor may exchange encrypted messages with the CP-chip. But even this exercise leaves the input to it vulnerable. Now for the 10c question: why should a DAT company spend a lot of resources on the CP part to do a good job here? After all, they are fighting this restriction. I think that the time it takes a person with EE background to defeat this circuit is best measured in minutes. -- Andreas
ken@argus.UUCP (Kenneth Ng) (06/27/87)
In article <1597@ihuxi.ATT.COM>, store2@ihuxi.ATT.COM (Kit Kimes) writes: > In article <67@sdeggo.UUCP>, dave@sdeggo.UUCP (David L. Smith) writes: > > How much do you want to bet that > > Radio-Electronics has an article "for experimental and educational purposes" > > on how to do it within a month after they come out? > Sorry, but the protection circuit will be buried deep in one of the LSI's. > There will be no way to remove it and even if you could, the notch will > still be there on the source CD. > Kit Kimes It will degrade the quality of the copy, but mixing in a low volume sound that is notched to match the CBS copycode scheme should bypass the scheme. One of the things that bugs me about the copycode scheme is that for the first time I can re-order songs the way I want to hear them, and with copycode I can't even do that, even if I bought the tape. Also, CBS claims that no normal music is present in the notched area. But if there isn't anything there, what does the notch do? I myself am willing to bet Radio-Electronics will publish a bypass mechanism, I may even build one. ... This signature was put in in a way to bypass the ... bogus artificial line limit on the .signature file. ... Also, by its length it adds fodder to help avoid having ... my followups being bounced due to the restriction on ... followup articles. Kenneth Ng: Post office: NJIT - CCCC, Newark New Jersey 07102 uucp !ihnp4!allegra!bellcore!argus!ken *** NOT ken@bellcore.uucp *** bitnet(prefered) ken@orion.bitnet
ken@argus.UUCP (Kenneth Ng) (06/27/87)
In article <1597@ihuxi.ATT.COM>, store2@ihuxi.ATT.COM (Kit Kimes) writes: > In article <67@sdeggo.UUCP>, dave@sdeggo.UUCP (David L. Smith) writes: > > Instead of messing about with the audio signal, why not just reach in with > > a soldering iron and clippers and tweak the chip out of the circuit, or > > make it think that it always has some noise there with a little 3800 HZ > > oscillator tied to its input. How much do you want to bet that > > Radio-Electronics has an article "for experimental and educational purposes" > > on how to do it within a month after they come out? > Sorry, but the protection circuit will be buried deep in one of the LSI's. > There will be no way to remove it and even if you could, the notch will > still be there on the source CD. Hm. after thinking this over, there is a good chance that the device will be by-passable. The CBS copycode scheme is only for DAT machines sold in the United States. Manufacturers will probably make the copycode circuit either a plug in module or switchable by soldering a pin high or low. Either way, there may be an easy way to remove it! ... This signature was put in in a way to bypass the ... bogus artificial line limit on the .signature file. ... Also, by its length it adds fodder to help avoid having ... my followups being bounced due to the restriction on ... followup articles. Kenneth Ng: Post office: NJIT - CCCC, Newark New Jersey 07102 uucp !ihnp4!allegra!bellcore!argus!ken *** NOT ken@bellcore.uucp *** bitnet(prefered) ken@orion.bitnet
phd@speech1.cs.cmu.edu (Paul Dietz) (06/29/87)
In article <921@argus.UUCP>, ken@argus.UUCP (Kenneth Ng) writes: > In article <1597@ihuxi.ATT.COM>, store2@ihuxi.ATT.COM (Kit Kimes) writes: > > It will degrade the quality of the copy, but mixing in a low volume > sound that is notched to match the CBS copycode scheme should bypass > the scheme... > ... Also, CBS claims that no normal music is present in the notched > area. But if there isn't anything there, what does the notch do? ... I hate to disagree with CBS, but "normal" music certainly has interesting things happening around 3800 Hz! Anyone who is unsure about this should take a quick look at the spectrum of most orchestral instruments. Maybe CBS is implying that only instruments with a big hole near 3800 are normal! :^) Ken brings up an interesting point. In order to trick the spoiler, he suggests filling the hole. What if instead of just filling the hole, we fill it proportional to the energy in the two adjacent bands? This only requires a single, fairly broad filter that spans the notch and the two adjacent bands. If you wanted to get tricky, you might even be able to use one of the spoiler chips to do the detection. Then one could use a cheap digital noise source for the filler. How good would this sound? Probably not so great. If that notch is 200 Hz wide, it's on the order of a musical half step. Partials can easily be entirely eaten by a notch that wide. Thus, the two adjacent bands don't really contain enough information for reconstruction. So, who's taking bets on how long before "Reconstruction" Filters appear on the market. (Next to the Monster Coax Speaker cable 8^)! ) --- Paul Dietz phd@speech1.cs.cmu.edu on ARPA, or ...!ucbvax!phd@speech1.cs.cmu.edu ... or something like that. "I take no responsibility for this post. My aides never informed me that they would be posting this, or that the data was being shipped to the Contras."
ron@topaz.rutgers.edu.UUCP (06/29/87)
There is no doubt that it will be easy to bypass the DAT copy protect circuitry. That is not what the fuss is over. The fuss is that to make copyprotect work it has to be impressed on the source material, ruining it for everyone. I doubt that I'll ever own a DAT unit. The only reason I have a cassette deck is to make tapes for my car, but since I don't have a cassette deck in the car, it is mostly unused. I do own CD players and a substantial amount of CD's already, if the music on CD's is further degraded. -Ron
asm@utcsri.UUCP (06/29/87)
[]
I suppose that if they do go ahead with this 3800Hz notch filter,
pre-recorded DAT offerings will be superior to pre-recorded CD
offerings (unless they notch the DAT recordings too). If this
is the case then the CD industry will suffer a loss of sales.
Does anyone know what the Q of the notch filter might be?
The prospect is not a pleasant one...
-anees
--
Anees Munshi @ University of Toronto Engineering.
ARPA asm%csri.toronto.edu@csnet-relay.arpa
BitNet asm@utcsri.UTORONTO
CSNet asm@csri.toronto.edu
UUCP {allegra,ihnp4,decvax,pyramid}!utzoo!utcsri!asmron@topaz.rutgers.edu (Ron Natalie) (06/30/87)
Nope, they'd have to notch the DAT prerecorded tapes or cause the player part of the DAT unit to insert the notch or you could copy DAT->DAT as well. -Ron
adam@gec-mi-at.co.uk (Adam Quantrill) (07/03/87)
In article <1597@ihuxi.ATT.COM> store2@ihuxi.ATT.COM (Kit Kimes) writes: <In article <67@sdeggo.UUCP>, dave@sdeggo.UUCP (David L. Smith) writes: <> <> Instead of messing about with the audio signal, why not just reach in with <> a soldering iron and clippers and tweak the chip out of the circuit, or <> make it think that it always has some noise there with a little 3800 HZ <> oscillator tied to its input. [..] <> <Sorry, but the protection circuit will be buried deep in one of the LSI's. <There will be no way to remove it and even if you could, the notch will <still be there on the source CD. That is what has everyone so up in arms. How about frequency-shifting the signal so that the notch is now at 3805Hz? A .2% speedup isn't subjectively noticeable. -Adam. /* If at first it don't compile, kludge, kludge again.*/
collinge@uvicctr.UUCP (07/06/87)
In article <1002@speech1.cs.cmu.edu> phd@speech1.cs.cmu.edu (Paul Dietz) writes: >I hate to disagree with CBS, but "normal" music certainly has interesting >things happening around 3800 Hz! >Ken brings up an interesting point. In order to trick the spoiler, he >suggests filling the hole. What if instead of just filling the hole, we >fill it proportional to the energy in the two adjacent bands? I suggest that, since 3800 Hz energy in music will be mostly harmonics of lower frequency tones, the thing to do is to put the music through a fuzzbox then filter out the 3800 Hz energy of the generated harmonics and intermodulation products. This has the advantage of correlating the synthetic stuff with the music that is already present - something the ear is extremely sensitive to. -- Doug Collinge School of Music, University of Victoria, PO Box 1700, Victoria, B.C., Canada, V8W 2Y2 collinge@uvunix.BITNET decvax!uw-beaver!uvicctr!collinge ubc-vision!uvicctr!collinge
wtm@neoucom.UUCP (Bill Mayhew) (07/07/87)
I heard that Marantz showed a DAT mahcine at the Chicago CES that DID NOT include copy protection. I saw an interview tape on "Boresight News" on satellite TV with a person claiming to be a Marantz rep. He said the CP idea was dumb. He said they weren't worried because the technical quality of the CP'ed CD is going to be so poor that who'd want to tape them any way? Also, you can get information on where to write nasty letters to expressing your opinion. Call 1-800-282-TAPE. This is apparently a nonprofit group that calls itself "The Consumer Recording Rights Coalition". I'd bet that it does have some financial backing from equipment makers, though. Bill
phd@speech1.cs.cmu.edu.UUCP (07/09/87)
In article <268@uvicctr.UUCP>, collinge@uvicctr.UUCP (Doug Collinge) writes: > I suggest that, since 3800 Hz energy in music will be mostly harmonics of > lower frequency tones, the thing to do is to put the music through a > fuzzbox then filter out the 3800 Hz energy of the generated harmonics and > intermodulation products. This has the advantage of correlating the > synthetic stuff with the music that is already present - something the ear > is extremely sensitive to. This is a very interesting proposal! It is based upon the assumption that most instruments generate harmonic partials in a fairly smooth fashion. This is quite reasonable for certain instruments, for instance, the brasses. However, some instruments have enharmonic partials (bells come to mind), and some have very pronounced gaps (like the clarinet) which give rise to the characteristic timbre. These might sound a little strange when a hole that was there before suddenly gets filled when running up a scale. Still, this is the sanest idea I've heard yet, and might be well worth the effort. (Of course, this is only for the real purists: I doubt most people will be able to notice the difference without an A/B comparison anyway!) I don't really know what a fuzzbox does (feel free to send me mail...), but I assume it's some sort of time invariant, non-linearity. For experimentation purposes, a saturating non-linearity might be reasonable (i.e. a comparator), but I suspect that it is not optimal. Out of curiosity, does anybody out there in netland know of any literature on the the spectral properties of various non-linearities? (i.e. things like exponentials, generic polynomials, and trigonometric functions...) Paul H. Dietz, Graduate Slave Laborer in Trumpet Acoustics phd@speech1.cs.cmu.edu on ARPA Dept. of Electrical and Computer Engineering Caregie Mellon University Disclaimer: I ASSUMED that the University was aware of my actions. However, they patently deny that they were ever informed...
collinge@uvicctr.UUCP (Doug Collinge) (07/12/87)
In article <1003@speech1.cs.cmu.edu> phd@speech1.cs.cmu.edu (Paul Dietz) writes: >This is a very interesting proposal! It is based upon the assumption that >most instruments generate harmonic partials in a fairly smooth fashion. >This is quite reasonable for certain instruments, for instance, the >brasses. However, some instruments have enharmonic partials (bells >come to mind), and some have very pronounced gaps (like the clarinet) >which give rise to the characteristic timbre. These might sound a little >strange when a hole that was there before suddenly gets filled when >running up a scale. Most real instruments change the shape of their spectrum for every note - since we are talking about probably only one partial no-one is likely to notice much. I think you would probably have to watch the amplitude of this synthetic partial but a little compromising given the average nature of musical sounds would probably do it. On the other hand: >I doubt most people will be able to notice the >difference without an A/B comparison anyway!) I have to agree with you but we'll wait for the blind tests. Does anyone know what the proposed bandwidth of this notch is? > >I don't really know what a fuzzbox does (feel free to send me mail...), >but I assume it's some sort of time invariant, non-linearity. Exactly, used for increasing the brilliance and sustain of electric guitar sounds. >(i.e. a comparator) Yes, typically, plus filters and various junk according to taste. -- Doug Collinge School of Music, University of Victoria, PO Box 1700, Victoria, B.C., Canada, V8W 2Y2 collinge@uvunix.BITNET decvax!uw-beaver!uvicctr!collinge ubc-vision!uvicctr!collinge
rbl@nitrex.UUCP (07/13/87)
In article <626@gec-mi-at.co.uk> adam@gec-mi-at.co.uk (Adam Quantrill) writes: >In article <1597@ihuxi.ATT.COM> store2@ihuxi.ATT.COM (Kit Kimes) writes: ><In article <67@sdeggo.UUCP>, dave@sdeggo.UUCP (David L. Smith) writes: ><> ><> Instead of messing about with the audio signal, why not just reach in with ><> a soldering iron and clippers and tweak the chip out of the circuit, or ><> make it think that it always has some noise there with a little 3800 HZ ><> oscillator tied to its input. [..] ><> ><Sorry, but the protection circuit will be buried deep in one of the LSI's. ><There will be no way to remove it and even if you could, the notch will ><still be there on the source CD. That is what has everyone so up in arms. > >How about frequency-shifting the signal so that the notch is now at 3805Hz? >A .2% speedup isn't subjectively noticeable. > -Adam. > >/* If at first it don't compile, kludge, kludge again.*/ How about doubling/halving both the CD and the DAT speeds? - rob
taras@utgpu.UUCP (07/17/87)
In article <1007@unh.cs.cmu.edu> agn@unh.cs.cmu.edu (Andreas Nowatzyk) writes:
# > Sorry, but the protection circuit will be buried deep in one of the LSI's.
# > There will be no way to remove it and even if you could, the notch will
# > still be there on the source CD. That is what has everyone so up in arms.
#
# It seems very unlikely that the copy-protection circuitry will be burried
# deep inside. Consider the nature of that chip: several filters, various
# integrators, gain-control, etc. (The block diagram was recently published in
# an audio magazin). This can be implemented either as an switched-capacitor
# device (a) or as a completely digital circuit (a).
#
Well if you were following the news you would know that the circuit has been
implemented by a US record and entertainment conglomerate, I forget who for the
moment. The DAT units are going to be sold in two implementations, (1) with
the defeat circuit included and the other without. The units without the
defeat circuit will have an empty space where the defeat circuit should have
been if it had been included.
Likewise it should not be all that difficult, for those inclined to do so, to
take the defeat circuit out. The circuit should also be defeatable by in-
jecting a very low strength 3khz tone into the signal. Just remeber the
copy-protection circuit sells for about $1.25 in volume.
# Now for the 10c question: why should a DAT company spend a lot of resources
# on the CP part to do a good job here? After all, they are fighting this
# restriction.
#
They wont!
# I think that the time it takes a person with EE background to defeat this
# circuit is best measured in minutes.
#
You do, do you. I don't, unless the EE was an electronic hack before he knew
what electronics was all about he will probably be all thumbs when he looks
at this thing.
# -- Andreas
--
Taras Pryjma
uucp: taras@gpu.utcs
bitnet: tpryjma@utoronto
Bell: +1 (416) 536-2821
Ok then, It's settled. I will have my computer call your computer and work
it all out. ....... But wait ...... it won't do any good, never mind.