My thinking is that nothing unique to either channel and nothing out of phase.should be there. The only signal true to the mono master is the one that is common to both channels.
What I don't know is how much of this is an artifact of my playback system.
What I don't know is how much of this is an artifact of my playback system.
Very interesting listening to those files!
First listen was all three in series then back and forth between them comparing. This is before reading any of the explanation as I didn't want to know what I was hearing.
The stereo was easiest to listen to. Clear and centred with good body in the headphone listening space .
The mono-sum has something going on that I find difficult to listen to - eyes/mind go out of focus and becomes very mildly irritating . Somehow I can't get a lock on it.
The M-S is somewhere between the two, much better than the mono sum and initially a little clearer or brighter than the stereo, but the accents at the end are still better in the stereo version, a bit richer?
It was also really interesting that after listening to the first two and then going to the third, the removal of surface noise is felt as though there is cotton stuffing blocking it out. Like being in a highly damped studio. I could "hear" the removed or blocked band as if it was a lower freq band of damping. Too late to know for sure but I doubt I would have perceived it had I not listened to the stereo and mono sum first. (Took another listen before reposting this. There is something I interpret as "phazey". Subtle but enough to notice after abrupt switching from the stereo file.)
Listened to with itunes on macbook and headphones out.
I'm not seriously technical with cart/arm/table combo lore but I can tell you that when I changed carts last year I was amazed at how all the surface noise I took for granted suddenly disappeared from all but a few of the records I've played since.
Great record, by the way !
First listen was all three in series then back and forth between them comparing. This is before reading any of the explanation as I didn't want to know what I was hearing.
The stereo was easiest to listen to. Clear and centred with good body in the headphone listening space .
The mono-sum has something going on that I find difficult to listen to - eyes/mind go out of focus and becomes very mildly irritating . Somehow I can't get a lock on it.
The M-S is somewhere between the two, much better than the mono sum and initially a little clearer or brighter than the stereo, but the accents at the end are still better in the stereo version, a bit richer?
It was also really interesting that after listening to the first two and then going to the third, the removal of surface noise is felt as though there is cotton stuffing blocking it out. Like being in a highly damped studio. I could "hear" the removed or blocked band as if it was a lower freq band of damping. Too late to know for sure but I doubt I would have perceived it had I not listened to the stereo and mono sum first. (Took another listen before reposting this. There is something I interpret as "phazey". Subtle but enough to notice after abrupt switching from the stereo file.)
Listened to with itunes on macbook and headphones out.
I'm not seriously technical with cart/arm/table combo lore but I can tell you that when I changed carts last year I was amazed at how all the surface noise I took for granted suddenly disappeared from all but a few of the records I've played since.
Great record, by the way !
In 78rpm shellacs the grooves are cut so that stylus moves only in horizontal direction (mono). But how are MONO V Groove vinyls are cut ? I mean is mono signal fed to cutter ? How will cutter head react to mono signal ? Pardon for newbie questions.
regards
regards
What is the difference between the noise created by a mono or stereo record when played with a stereo cartridge? None!
If the dust particle sits on one groove side, it will create a left/right side pop, if it sits in the middle and creates a pure vertical stylus movement the click will be in both channels, but with a 180 degree phase shift as to my knowledge, one signal is inverted when cutting a stereo disc wich is removed by wiring the cartridge coils accordingly. When summing up, this symmetrical noise will be eliminated while a pure left / right side click will get attenuated by 6 dB.
Is there any description in the SW documentation of what exactly the side attenuation is doing?
There must be some processing going on that does a better supression than 6dB for the 'one sided' clicks and pops to make the total noise rejection more effective than mono summing alone.
I can only speculate but maybe the SW builds the sum of left and right signals and the difference. The difference is then deconvoluted into the left and right difference from the sum, then these differences are subtracted from the left and right signal accordingly before creating the final mono signal.
I'm not entirely convinced. A mono groove is constant depth so the stylus is not being jiggled around in +/-45 direction all the time. If the stylus is already in motion in that plane there is more likelyhood of perturbation from dust adding to it. Easily tested by playing a mono record with a stereo cartridge and looking for uncorrelated noise on left or right channels.
What is of more interest to me in this thought train is that this shows a logical reason for having lower compliance and higher VTF cartridges for mono than stereo. I did obtain a Shure SC35 for experiments as that is 5CU but ended up selling that on to someone else on here. But I do have an ortofon S120. This was designed as a DJ cartridge but has a trick suspension so it is much stiffer in the vertical plane than horizontal. This might work and is certainly worth the test. I also have a couple of OM DJ inserts with around 7CU compliance and I can compare those with the OM10 insert to see if compliance makes any difference.
A stereo cartridge is designed to follow excursions in all directions (360 deg) for the entire frequency range from 20 Hz up to 20 kHz. So there must be no discrimination if the stylus is moving in the lateral plane most of the time and only occasionally has to move in another direction or if this happens all the time. When playing a mono record, only one direction is used intentionally. But any dust particel on one groove wall will make the cantilever move in the 45 deg direction of one channel. And when playing a mono record in a stereo setup and listen to the noise and clicks, you can easily hear clicks coming from one side alone (left or right) and clicks coming from the center - so it simply depends on where the dust particle sits.
Having higher tracking forces could also have a negative effect as higher forces may also 'hammering' hard microparticels into the groove wall while carts with lower tracking force will 'jump' over the particle.
But instead to rely on the cartridges to supress the pops and clicks and mostly focus on this aspect we should as a first step clean / wash the disc before playing - this is always good for the record and for the stylus. I wash all my records before playing them the first time, the remaining clicks, crackles and pops are then coming from already damaged grooves.
And then we can focus on how the sound quality can be maximised by cartridge types, wiring and system setup.
I think you are missing the amount of 'snow plough' effect that a stylus has. A dust spec will be just knocked out the way.
For the bigger particles I fully agree. The more dangerous particles are the really small ones - e.g. smaller than tip radius - and the really hard ones with sharp edges. There have been reports published in the 70s / 80s stating that such particles grind down your diamond tips and the groove walls and are pressed into the vinyl and then cannot be washed away anymore (have seen such a report with microscope pictures, unfortunately don't remember report title). Also cartridge manufacturers say that dirty records will reduce stylus lifetime and therefore recommend to keep records clean.
That something I need to do. I suspect this Stanton cart is a little too good at picking up record noise. The heavy tone-arm I use needs a low compliance stylus. My budget needs a cheap one. 🙂
No, not exactly. It does seem to use fast Fourier transform. I have not been able to manually get the same results that it does. The closest results came from: Stereo minus mono sum = difference. Then Stereo minus difference followed by mono summation. That is similar, but not as strong. I'll post a screenshot of the effect in a few minutes.
That is exactly what I posted here. Listen to the stereo file which is a 1957 mono LP ripped with a stereo cart. The uncorrelated noise is easy to hear.
Could be. My Stanton 681 is low compliance tracking at 3g. I'm pretty sure it's more compliant in one axis vs the other, as test record grooves cut vertically don't produce the same amplitude as those cut laterally. A new Audio Technica DJ cart is in my future it seems.
I certainly agree and I do wash everything. The LP that had not been cleaned was for demo purposes. But because I buy many cheap old LPs I have no control over how dirty or damaged they are. Cleaning helps, but only so much.
Getting low noise playback ought to be part of the Fun of Mono. If there are valid techniques to improve the S/N ratio with mono, we should pursue them.
my bad, had misread an earlier post.
Even after scrub and vac clean on first play some of mine pull out huge amounts of good. A multistage process may be needed for some
Definately
Now after having some side stepping coming back to the initial starting post
For the first three ways to play mono records I have some own experience, for the 4th some for summing up in the preamp or phonostage.
1. I have a real mono cartridge (GE VRII) and it sounds pretty good - better than any mono converted MM pickup I tried so far. If this is the result of beeing a true mono cartridge or the result of the construction principle of the cart I can't tell. The only way to find this out would e.g. to compare the modified ortofon cartridge (for pure lateral and vertical outputs) to a stock Ortofon cartridge of the same type.
2/3. Parallel / serial strapped stereo cartridge. I tried both and like the serial connection better. Hard to describe but somewhat more detailed, more open. Explanation could be that in a parallel conection there are currents flowing from one generator into the other one (circular currents) for all signals different between left and right wich does not happen in the serial connection. But when doing serial connection at least for MM cartridges (I did not try MCs so far) the phono input impedance must be twice as high as for normal stereo connection (47 kOhm > 100 kOhm and total capacitance half the recommended value as the two generators are in series and thus resistance and inductance double compared to one genertor alone, in a parallel connection, resistance must be halfed to 25 kOhm and capacitance doubled). This was one reason to build a dedicated mono phono pre as also the GE cartridge is specified for 100 kOhm input resistance (this cart was developed prior the standardization to 47 kOhm)
4. Mono connection in he phono stage itself was working ok but sound was better - at least in my case- when mono connection was done at the cartridge and only one channel was used as mono amp.
I have no experience for DSP approaches as e.g. described by Pano
For the first three ways to play mono records I have some own experience, for the 4th some for summing up in the preamp or phonostage.
1. I have a real mono cartridge (GE VRII) and it sounds pretty good - better than any mono converted MM pickup I tried so far. If this is the result of beeing a true mono cartridge or the result of the construction principle of the cart I can't tell. The only way to find this out would e.g. to compare the modified ortofon cartridge (for pure lateral and vertical outputs) to a stock Ortofon cartridge of the same type.
2/3. Parallel / serial strapped stereo cartridge. I tried both and like the serial connection better. Hard to describe but somewhat more detailed, more open. Explanation could be that in a parallel conection there are currents flowing from one generator into the other one (circular currents) for all signals different between left and right wich does not happen in the serial connection. But when doing serial connection at least for MM cartridges (I did not try MCs so far) the phono input impedance must be twice as high as for normal stereo connection (47 kOhm > 100 kOhm and total capacitance half the recommended value as the two generators are in series and thus resistance and inductance double compared to one genertor alone, in a parallel connection, resistance must be halfed to 25 kOhm and capacitance doubled). This was one reason to build a dedicated mono phono pre as also the GE cartridge is specified for 100 kOhm input resistance (this cart was developed prior the standardization to 47 kOhm)
4. Mono connection in he phono stage itself was working ok but sound was better - at least in my case- when mono connection was done at the cartridge and only one channel was used as mono amp.
I have no experience for DSP approaches as e.g. described by Pano
That's good info. I had been wondering about the serial vs parallel wiring vs real mono cart.Don't get me wrong. I fully agree on what has been said so far. The ultimate goal is to find a system setup that gives the best possible sound experience for the music played and this definitely also includes measures to improve S/N ratio at the same time. And background noise is a sad fact for most of these old discs. Really mint records are quite rare and almost impossible to get - at least for reasonable prices - when it comes to records from before the 50's.
Cleaning / washing should always be the first step to remove any dirt that can be removed but already damaged grooves cannot be restored that way - here we need other methods. The trick is to find the best compromise between optimal background noise suppression and minimal impact on the music / speech signal itself.
Interesting to read the treasure of info you post. I have a simple Quad 33/303/ESL57 system and a Denon DL102 cartridge. To me it sounds different using the mono button (mono/L/R) on the Quad 33 compared to the stereo button with the Denon DL102. Still collecting more and more mono LPs 🙂. Is there actually a difference between an original mono pressing and a modern re-released one?
Clicks and pops can be down in the groove, but many which result from scratches are not, they are on the surface of the record. I have seen evidence that they can be removed. When the record surface is scratched the record material is deformed and a segment of the vinyl encroaches into the groove, but this is almost entirely at the top of the groove. I saw on youtube a demonstration by a collector who very carefully polished the surface of an lp and removed most of the bad surface noise from a thrift shop record. It was very impressive, though frightening at first to see him using abrasives, no matter how fine, on a record, but the results spoke for themselves.
One would suppose that modern mono LPs have been cut with a stereo lathe. In the 1950s they would not have been. I have read about some modern boutique shops with mono cutters.
Scary - but if it helps making a bad record listenable again, why not. Maybe I try it on a really badly scratched record and which is not a real rarity to see if it makes it a little better again.
Do you have some more info on it? abrasive used? direction of 'polishing'?