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What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #25
Clipping is similar to a square wave in that the tops and bottoms are flat plateaus.

Now, CDs will store whatever values you want to store on them, being digital as they are..

What would the lathe-cutter do on the vinyl master.. would it be able to keep the plateaus flat? And what about the playback cartridge/needle? You've got two analog steps there that could degrade the square wave.

So if you can find some data about reproducing square waves on vinyl, I think that will provide your answer.
--  tung  --
http;//tung.co

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #26
You know, given that this whole debate over the GH3 mixes etc has been 2+ weeks old, I've kind of wondered why HA has had so relatively little discussion on the Death Magnetic phenomenon recently. Has everybody but me been busy at the AES convention or something?

Metallica died with Cliff Burton.
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #27
You know, given that this whole debate over the GH3 mixes etc has been 2+ weeks old, I've kind of wondered why HA has had so relatively little discussion on the Death Magnetic phenomenon recently. Has everybody but me been busy at the AES convention or something?

Metallica died with Cliff Burton.


Well.. the Loudness War controversy is heating up big time!
--  tung  --
http;//tung.co

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #28
Ian's still arguing that less clipping = better, which is great. But I think he's mudding the waters significantly by claiming the vinyl version is better without getting to the bottom of why it sounds better. Attributing it to a mix change is a classic audiophile fallacy (attributing audible differences to intrinsic properties rather than extrinsic ones).



As maybe you've seen, (and with some inevitability  ), I have weighed in there to note the subjective bias cannot be ruled out as a factor in Ian's preference, by the (sighted, crudely level-matched) method he used.

So searching for the 'why ' of it purely in measurements of output, won't necessarily give the 'complete ' answer.

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #29
Jesus, krab. I just couldn't imagine what kind of response you'd get directly questioning a mastering engineer's listening skills, could I?

Although if I had to venture a guess, it would probably involve a reference to a classic rock band.

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #30
Clipping is similar to a square wave in that the tops and bottoms are flat plateaus.

Now, CDs will store whatever values you want to store on them, being digital as they are..

What would the lathe-cutter do on the vinyl master.. would it be able to keep the plateaus flat? And what about the playback cartridge/needle? You've got two analog steps there that could degrade the square wave.

So if you can find some data about reproducing square waves on vinyl, I think that will provide your answer.


Just googled this a bit, found this thread that includes you, Axon:

http://recforums.prosoundweb.com/index.php...1/0/#msg_377851

I'm in agreement with Cerberus.

I think it's related to the inability to accurately reproduce a square wave. As a result, the plateaus end up sloping, resulting in a recording that sounds "nicer" than the clipping a CD is capable of storing.
--  tung  --
http;//tung.co

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #31
Jesus, krab. I just couldn't imagine what kind of response you'd get directly questioning a mastering engineer's listening skills, could I?



  So far there doesn't seem to be any.

On further consideration, to make it *really* fair, I'd tell the subject that BOTH were from CD (or LP).  Or tell them nothing at all about the sources.  Then they're 'purely' comparing SQ.


Quote
Although if I had to venture a guess, it would probably involve a reference to a classic rock band.


as long as it's not CREEDENCE, MAN!

Anyway, if my little reality-check does nothing more than make steam come out of Fremer's ears, it will have been worthwhile.

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #32
Mikey won't respond. Hell, did he even read the original post? His response sound like he stopped reading at "vinyl sounds better".

Anyway, Ian's across the pond, give the man some time.

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #33
I'm in agreement with Cerberus.

I think it's related to the inability to accurately reproduce a square wave. As a result, the plateaus end up sloping, resulting in a recording that sounds "nicer" than the clipping a CD is capable of storing.
Plenty of records exist out there that reproduce square waves just fine. CBS STR 112, for starters.

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #34
I'm in agreement with Cerberus.

I think it's related to the inability to accurately reproduce a square wave. As a result, the plateaus end up sloping, resulting in a recording that sounds "nicer" than the clipping a CD is capable of storing.
Plenty of records exist out there that reproduce square waves just fine. CBS STR 112, for starters.


OK.. I wonder what that waveform would look like when sampled from the same turntable setup as used on the OP?
--  tung  --
http;//tung.co

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #35
Mikey won't respond. Hell, did he even read the original post? His response sound like he stopped reading at "vinyl sounds better".

Anyway, Ian's across the pond, give the man some time.



No problem. IS seems pretty level-headed as regards vinyl vs digital...he's certainly no Fremer.


Btw, I hadn't visited PSW in ahwile, but thsi thread prompted me to do so.  I found this relevant gem from Bruno Putzys, on a thread about the future of DSD (which so many 'audiophiles' claim comes 'closest to vinyl')


Quote
The "so many xyz can't be wrong" argument is based on the notion that a lot of anecdotal evidence should somehow be worth a single piece of properly controlled evidence. Not so. I'm still waiting for anyone who's done a comparison between DSD & PCM that wasn't somehow flawed (e.g. using different converters) or badly controlled (e.g. sighted) and that still demonstrated a clear advantage of DSD over PCM. One is reminded that DSD *is* PCM, albeit at a 1 bit word length at a higher sampling rate. So what aspect of DSD is the one that does the magic? The use of one bit? Very few DSD converters actually convert directly to one bit (mine does). Is it the high sampling rate? Never mind that DSD chains typically have 50kHz lowpass filters? Or is it the indispensible noise shaping that somehow imparts magic to the music? I'd say long live sigmadelta modulation (single or multibit alike) because it allows one to make great converters, and long live PCM because it offers the best SNR/Bandwidth combination for any given data rate (and allows you to do more to a signal than just store it).


I'm in agreement with Cerberus.

I think it's related to the inability to accurately reproduce a square wave. As a result, the plateaus end up sloping, resulting in a recording that sounds "nicer" than the clipping a CD is capable of storing.
Plenty of records exist out there that reproduce square waves just fine. CBS STR 112, for starters.


Paul Gold noted that it's not that cutting heads can't cut square waves; it's that TT cartridges can't track them accurately.

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #36

I'm in agreement with Cerberus.

I think it's related to the inability to accurately reproduce a square wave. As a result, the plateaus end up sloping, resulting in a recording that sounds "nicer" than the clipping a CD is capable of storing.
Plenty of records exist out there that reproduce square waves just fine. CBS STR 112, for starters.


OK.. I wonder what that waveform would look like when sampled from the same turntable setup as used on the OP?
As was discussed, there are two different turntables involved in the two different images, but certainly, my use of high-order highpass filtering in my rumble filter will skew things a lot in my setup.

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #37
I asked at PSW if they've ever heard of using an allpass in mastering, and one vinyl engineer shot that idea down cold.
Some compressors have dynamic all-pass filter-like behaviour. These are certainly used in radio broadcasting - I'm sure similar equipment makes it way into some recoridng/mastering studios.

Don't trust these people to know what their equipment actually does. They're "arty" types. To actually understand the technology would make them too "geeky" to work in their "profession".

Quote
This is an extremely important question because some mastering engineers are using these waveform plots as supporting evidence to show that the vinyl masters are different from and superior to the CD masters.


Well, that's just silly. It says...
Quote
The upper (CD) waveform is digitally clipped or "squared off", as expected, but the unexpected part is the vinyl version - it's a very unusual, unnatural shape because of the distortion, but it's not squared off. This explains why the vinyl sounds better - although harsh, the analogue distortion hasn't completely removed all the remaining dynamics. Extreme digital clipping of this kind on the other hand, where the whole wave becomes almost square, obliterates pitch information - the ear can't resolve the original fundamental or it's harmonics. Impact and punch are lost, too - the result sounds two-dimensional and plastic in comparison.

Some people on the Metallica forums expressed the opinion that the extra "peak" information on the vinyl didn't represent "real" musical information, simply the inherent difference in the format. Initially, I was inclined to agree, but after doing these listening tests myself I don't agree - the vinyl is less clipped than the CD and sounds better as a result.


A best guess would be that the vinyl is mastered from the CD (or at least the same master) - and that the additional "analogue" distortion on the vinyl version has sweetened or softened the "digital" distortion on the master itself. Whether it's closer to an undistorted master is anyone's guess - probably not. It's an expensive (not to mention silly) way of sweetening the sound. Much easier to buy the CD and throw some DSP at it. You could just record the CD onto tape, and then play it back. Or the record company could simply trash the CD version less to start with!


If they can make a single trashed master, release it on vinyl, charge more for it, and then have fans claim that it's not quite as bad as the CD, they must be laughing!

If this is music you really love, then I suppose you might be driven to all kinds of extremes to try to find/make a better sounding version.

Cheers,
David.

P.S. As others have said, I don't understand how the author can believe the vinyl is from a less compressed master - the graphs show exactly the same level of clipping, plus a high pass filter - that's it!


I totally agree. Personally I'm getting a bit peeved at the thought that major labels may start really pushing the vinyl as the "audiophile" version when they are often made from the same crappy overcompressed 2-track master.
--  tung  --
http;//tung.co

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #38
Couldn't you just look at the LP under a magnifying glass or a good scanner and see if it's on the LP itself?

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #39

I'm in agreement with Cerberus.

I think it's related to the inability to accurately reproduce a square wave. As a result, the plateaus end up sloping, resulting in a recording that sounds "nicer" than the clipping a CD is capable of storing.
Plenty of records exist out there that reproduce square waves just fine. CBS STR 112, for starters.


OK.. I wonder what that waveform would look like when sampled from the same turntable setup as used on the OP?
As was discussed, there are two different turntables involved in the two different images, but certainly, my use of high-order highpass filtering in my rumble filter will skew things a lot in my setup.


I would bet if you digitally recorded a square wave signal from that test LP you referenced from both setups (I didn't catch the specs on your setups, btw) you'd see the same sloping situation, and you'd end up with a softer-sounding square wave.

And I tend to think the DM LPs are from the same brickwalled 2-tracks.
--  tung  --
http;//tung.co

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #40
I would bet if you digitally recorded a square wave signal from that test LP you referenced from both setups (I didn't catch the specs on your setups, btw) you'd see the same sloping situation, and you'd end up with a softer-sounding square wave.

And I tend to think the DM LPs are from the same brickwalled 2-tracks.

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #41
I would bet if you digitally recorded a square wave signal from that test LP you referenced from both setups (I didn't catch the specs on your setups, btw) you'd see the same sloping situation, and you'd end up with a softer-sounding square wave.

And I tend to think the DM LPs are from the same brickwalled 2-tracks.


OK.. I think I missed that the squared-off part was a fairly high frequency, isn't that the case?

Really, I would call myself an audio technology enthusiast, and I don't have enough of the mathematical background to really grok group delay, but I just thought I'd offer my impression, for what it's worth.

So it may not be audible, but I'd still be curious to see square waves of different frequencies digitally sampled from a turntable output.. I would expect some sloping. Possibly also a bit of anger on the part of the cartridge that was asked to reproduce it.
--  tung  --
http;//tung.co

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #42
I think so too.  This is what our rumble filter makes of a 1kHz square wave.  This is a cascade of 3 second-order high-pass IIR filters rolling off at 30 Hz:



But that's not to say it couldn't be mechanical in origin.  I guess we'll never know.
I am an independent software developer (VinylStudio) based in UK

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #43
As I pointed out over a month ago in one of Axon's related threads (and linked to earlier in this thread), it's a physical impossibility to get a perfect square-wave from vinyl even if one existed on the vinyl in the first place. You'd have to defy the laws of physics to do it.

The output of a magnetic cartridge is proportional to rate of change. If the needle doesn't move, there's no output, ie, you can't get a DC level out of one. The needle doesn't move during the flat portions of the square-wave, therefore, no input-compliant output from the cartridge. The cartridge is an AC generator consisting of either a magnet moving inside a coil (MM) or a coil moving inside a magnet (MC). No movement equals no output.

All you're left with is a voltage decaying towards zero with a time constant determined by the capacitive coupling time constants in the preamplifier stage and the physical inertia of the cartridge and tone-arm.

The effects will be less prominent as the frequency goes up, but they will always be there to some extent.

Come on, guys! This is basic schoolboy physics! I'm amazed that some HA members are having such a hard time of it trying to wrap their heads around it to be honest.

Cheers, Slipstreem. 

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #44
Slipstreem is right, of course.  Otherwise we would have invented the perpetual motion machine.
I am an independent software developer (VinylStudio) based in UK

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #45
The output of a magnetic cartridge is proportional to rate of change.


Does it mean that the shape of a groove must be antiderivative of a waveform itself? Triangle (sawtooth) groove will then produce good enough square wave.

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #46
Couldn't you just look at the LP under a magnifying glass or a good scanner and see if it's on the LP itself?


that had crossed my mind too, but i to see this close into the wave form would take at least a good optical microscope, if not something better (electron microscope?)

edit: btw im no expert, but just looking at one of my vinyls, i can say that a magnifying glass/good (conventional) scanner is not going to give the power needed to see that close up, maybe some extremely high powered scanner, i dont know
My $.02, may not be in the right currency

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #47
Should do, if you get the slope exactly right (and until you run out of needle travel).

[Edit]
Actually, that's not quite right, is it?  You need to master a square wave with sloping tops and bottoms, the slope of which is the inverse of the 'droop' introduced on playback.  A bit like this:



This was generated from a 1kHz square wave by adding a 12dB boost at 31Hz and 63Hz.  And limiting needle travel is, of course, what RIAA equalisation is all about.
[edit]
I am an independent software developer (VinylStudio) based in UK

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #48
Does it mean that the shape of a groove must be antiderivative of a waveform itself? Triangle (sawtooth) groove will then produce good enough square wave.
You could "anti-slope" the waveform at the recording stage to overcome this in theory, but how would you know how much correction to apply? It's going to vary from one playback system to another, possibly quite dramatically.

I'm glad that Paul bought up the perpetual motion argument. That was going to be my next tack if the explanation in my previous post didn't get the basics across. However, just in case, assume that you have a loudspeaker laying on its back with the cone uppermost. Place a voltage meter across the terminals and lower a weight onto the cone and what do you get?

You see a deflection on the meter as the cone moves under the mass of the applied weight. When the cone reaches the limit of movement imposed by the weight and becomes stationary again, you have no output. Exactly the same thing is going to happen with either a MM or MC magnetic cartridge. Movement = output. No movement = no output.

If holding the needle in a fixed position in the case of a cartridge or the cone in the case of a loudspeaker produced a steady DC output, we'd have energy for nothing.

Cheers, Slipstreem. 

What does it mean when a clipped waveform on vinyl is "sloped&quo

Reply #49
Does it mean that the shape of a groove must be antiderivative of a waveform itself? Triangle (sawtooth) groove will then produce good enough square wave.
You could "anti-slope" the waveform at the recording stage to overcome this in theory, but how would you know how much correction to apply? It's going to vary from one playback system to another, possibly quite dramatically.

I'm glad that Paul bought up the perpetual motion argument. That was going to be my next tack if the explanation in my previous post didn't get the basics across. However, just in case, assume that you have a loudspeaker laying on its back with the cone uppermost. Place a voltage meter across the terminals and lower a weight onto the cone and what do you get?

You see a deflection on the meter as the cone moves under the mass of the applied weight. When the cone reaches the limit of movement imposed by the weight and becomes stationary again, you have no output. Exactly the same thing is going to happen with either a MM or MC magnetic cartridge. Movement = output. No movement = no output.

If holding the needle in a fixed position in the case of a cartridge or the cone in the case of a loudspeaker produced a steady DC output, we'd have energy for nothing.

Cheers, Slipstreem. 


i think this is generally what JAZ tried to say a while ago
and of course this is entirely true, i still find it interesting if you CAN cut a square wave on a vinyl
My $.02, may not be in the right currency

 
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