Crosstalk: digital more like Vinyl?

[Phelonious Ponk]

Wake up on the wrong side of the bed Tim?

No just keepin' it real. F1eng, I hope you saw my tongue in my cheek there.

Tim

 

[LL21]

Again, enjoying Atmasphere, Jkeny and F1s discussions here...slowly learning...thanks gents.

 

[RogerD]

No,
I'm talking about the opposite.

Maybe we need to distiguish between 2 types of crosstalk at least:
1. crosstalk in analog circuits between channels
2. crosstalk from hearing the sound of two (or more) speakers with each ear

For 1) we have learnt for long time that we should avoid it.
For 2) we have different approaches to solve the problem, e.g. RACE and BACCHamongst others

I'm talking now about 1) The digital world does not know about crosstalk. Maybe we get it at the end when it comes to DA conversion and analog amplification. IMO this is a possible reason why the digital playback sounds digital and a perfect playback (free of crosstalk) worsens the result.
So it seems that a bit of frequency dependent crosstalk helps and it is recognized as comfortable, less nasty and more relaxing. IMO a possible reason is that the frequency dependent broadening of stereo playback gets reduced. A better localization relieves the brain.

So I'm talking about adding crosstalk which is the opposite of cancelling crosstalk

- Uli

Thanks......so I understand now what you are doing. Do you add the crosstalk with your ambiosonic circuit in operation. I would think that if you add ambiosonics that should relax the reproduction. In my experience there are two main causes of a unrelaxed presentation. Noise(EMI) and Ambiosonic targeted distortion. Is your goal to do this all in the digital domain?

 

[esldude]

http://www.whatsbestforum.com/showt...o-reproduction&p=282088&viewfull=1#post282088

The files I attached to post #19 in this other thread might be of interest to those taking part in this thread also.

 

[f1eng]

I could not let this pass. Its patently untrue. What is true has to do with out-of-phase information, something that rarely if ever shows up with a live recording. But if it does, and is so bad that you can't get around it by changing the level slightly or cutting a deeper groove, the processor that takes care of it will only make the bass mono for a few milliseconds at most. I've often thought we would need such a thing (which BTW is otherwise a passive device in the signal chain) but so far have yet to see a recording where this is required. So every stereo LP we have done also has full-stereo bass.

You are not strictly correct here. Each channel is recorded on one side of the groove, it can also be seen as the horizontal stylus movement is the mono part of the signal and the vertical the difference, but which ever way you look at it, if the modulation exceeds root 2 times the mean groove depth the groove will cease to be continuous. It is true that a lot of (probably most) music does not have big bass modulation on one channel only orchestral music often can, since the conventional orchestral layout has double basses on the extreme right.
I put my cheap USB microscope on the last disc I took off my turntable, Richter Lizst Piano Concerto 1, Kondrashin/LSO Philips SABL207 1961, and there are clear areas there where the groove modulation exceeds the groove width, so the bass certainly isn't all on one channel there.

Anyway, you clearly are very careful in your recordings, hats off, and haven't needed to do it. I know of engineers back in the day who just monoed the bass anyway to be sure, sloppier than you but probably producing cuts in huge numbers compared to today.

I looked on your website to check out your LPs but only found the rather exquisite looking amplifiers. Do you have a list somewhere? Always interested in uncompressed classical recordings.

Analog tape can do full output at any frequency within the passband. LP you do have to watch it, but it is not as fragile as suggested. But there will never be a full output signal at high frequencies recorded in any media except for testing- most tweeters don't handle more than a few watts for the same reason...

It is true that high levels at high frequencies are rare, which is one of the several reasons why the "fuzzy" letterbox I referred to earlier is fuzzy.

FWIW the RIAA curve does not specify a high pass filter beyond that of the curve itself. There are such filters in use but they are not part of the RIAA curve.

Actually I am very aware of how cartridges playback and their interaction with the arm! All mastering engineers have to understand the limitations of the playback apparatus.... The mechanical resonance describes the lower limit of any LP playback system. Upon listening to the digital backup we found the 8Hz (or thereabouts) to be a foot stomp, with exactly 1 sine wave iteration. It was at low level, and since we were doing direct to disk there was not a lot to be done about it.

The 1950s RIAA curve did not have a high pass filter built in. The 1976 RIAA curve did.

The mechanical resonance is not the lower limit of an LP replay system. At the resonance the cartridge body is bouncing around on the stylus compliance (i.e. resonating), producing a boosted output at that frequency, how boosted varies from design to design. The bounce at resonance is less with high cantilever damping but this creates a shortcoming at higher frequency where the damping "short circuits" the suspension reducing accuracy. Less damping produces much bigger amplitude at resonance but is more accurate at higher frequencies. Designers have to consider this carefully because you can't have both and it is one of the difficulties of designing seismic type transducers (I designed my first one in 1972 FWIW).
Convention has it that by 2x resonant frequency the phase shift is largely complete and the mass is stationary relative to the moving element such that the output signal is proportional to the movement of the moving element from that frequency up. This is near enough true as a rule of thumb. So a turntable assembly with arm/cartridge resonance at 10Hz will start to produce accurate output from about 20Hz up. Lower than 20Hz it is not accurate but the degree of the error is hugely cartridge design dependant. It makes total sense (to me!) to use the 1976 RIAA curve rather than the 1955 (I think it was 1955 may be wrong)

In practice I've never had to compress any classical recording I have done. If you can put it on analog tape, you can put it into the LP too, as it has wider dynamic range than analog tape does, with a lower noise floor.

True.

I am of the opinion that the highs of the LP are preferable as there is less distortion of the types that are annoying to the human ear/brain system, and otherwise less phase shift with more bandwidth.

You may be right here but it is not what I would expect.
Again this is massively cartridge design dependant. Some great sounding cartridges roll off early, on one extreme the fabulous Techdas, for example, starts rolling of at 10kHz. Others are extended but have resonant peaks near 20kHz, or above, producing all sorts of phasey spurious output up there. Almost all have double digit distortion by 20kHz too. Phase accuracy between channels when using exotic styli is effected by cartridge alignment and the precision of stylus to cantilever alignment.
So whilst supersonic frequencies can theoretically be cut onto LPs a combination of wear and the physical limitations of cartridge design mean that getting anything meaningful out of the phono stage is unlikely at these frequencies, it is entirely feasible that most of the output at >20kHz will be distortion products and resonance artefacts with many cartridges.
This hash is avoided by designs such as the Techdas, by rolling off earlier. A wise design choice IMHO

 

[Atmasphere]

Thanks for your comments about the mechanical resonance!

Regarding bandwidth I think there are some cartridges that are problematic, but most I have used over the years have had no troubles going up quite high. I think I mentioned earlier on this thread that we tracked 30KHz with a Grado Gold without any worries- the scope trace looked pretty good. This despite that fact that we were playing back **outside** the normal 12" diameter since we were cutting on a 14" lacquer, and the tone arm geometry is pretty poor when you are tracking that far out from the center of the disc. This is a handy technique if you want to get an idea of how your cutting method is working in a situation where you can't/won't play the actual LP region of the lacquer. A longer arm would help but we use the Technics SL1200 is it is a very common turntable that is likely to be used with the finished product.

In all this its very apparent that the arm and cartridge is the leading edge of the development of the art, as that is where the main limitations of the format lie.

 

[f1eng]

This despite that fact that we were playing back **outside** the normal 12" diameter since we were cutting on a 14" lacquer, and the tone arm geometry is pretty poor when you are tracking that far out from the center of the disc. This is a handy technique if you want to get an idea of how your cutting method is working in a situation where you can't/won't play the actual LP region of the lacquer.

What a clever idea.
Where can I check out your LPs (PM me if you prefer)?

 

[jkeny]

BTW, what do you guys think of linear tracking tonearms? Ive heard a version of this air bearing linear tracking tonearm & was mighty impressed with the tracking & the sound. Compared very favourably, if not bettered a unipivot tonearm

 

[f1eng]

BTW, what do you guys think of linear tracking tonearms? Ive heard a version of this air bearing linear tracking tonearm & was mighty impressed with the tracking & the sound. Compared very favourably, if not bettered a unipivot tonearm

2 of my 4 turntables have parallel tracking arms.
It is a difficult balance. Tracking error is one of the non-euphonic additions made by record players. Parallel tracking arms resolve this but many (including your link) have high lateral effective mass, which can make cartridge matching and LF performance a problem.
Again, the designer has to choose his compromises to match his preferences. All tonearm concepts have at least one shortcoming...

 

[Atmasphere]

I like linear tracking arms but not the kind with air bearings for the reasons mentioned just above and more: air bearings by definition have some slop in the bearing mechanism, which should not be present if the playback is to be done without coloration or mistracking problems. The engineering issue is not unlike the suspension and steering of a car or motorbike- any slop in such systems results in handling problems. There should be no play between the surface of the platter and the mechanism that holds the cartridge in locus. If there is, and if the coupling between the platter and the base of the arm is not rigid and also free of vibration, the result will be interpreted as a coloration.

If there is one area where digital really works this is it- you just don't have the setup problems and outright engineering bugs that seem to plague LP playback apparatus!

 

[Bruce B]

BTW, what do you guys think of linear tracking tonearms? Ive heard a version of this air bearing linear tracking tonearm & was mighty impressed with the tracking & the sound. Compared very favourably, if not bettered a unipivot tonearm

The air bearing linear tracking arms I've heard have great imaging and spaciousness at the cost of bass, dynamics and body.

 

[jkeny]

I hear what you are all saying & I know the guy who built this arm used the usual tracking test record on it (forget what one) & he said it passed all tests including the very difficult one that most arms have trouble with or fail - I think it did better than all his other arms?

I don't remember any problem with bass, dynamics or body but I would have to revisit it again to be sure.

 

[wisnon]

I am a digital dude. But I can't deny that sometimes vinyl systems can offer something digital struggles to deliver. We often hear folks pay a compliment to digital when they say it sounds "analog."

I love using DSP in my system. Recently, I switched over to Acourate.
http://www.audiovero.de/en/acourate.html

Since then I've been introduced to a setting in the Acourate Convolver called "flow." The basic idea is to set the parameters to permit some small frequency dependent crosstalk. The author's words explain it well:
http://digitalroomcorrection.hk/http___www.digitalroomcorrection.hk_/AcourateFlow.html

In summary, Uli's theory is that vinyl's perceived technical weakness (high cartridge crosstalk) can actually be very beneficial to better stereo reproduction.

I've tried it out and I really like it. It's not a huge difference. However, the music does sound a little more natural without any loss of resolution. It's cool!

Can DSP really be used to make digital playback sound more like vinyl?

Michael.

DJ is Acourate "better" than the Spatial computing approach? Have you heard Spatial yet?

 

[wisnon]

The air bearing linear tracking arms I've heard have great imaging and spaciousness at the cost of bass, dynamics and body.

Hi Bruce,

Have you ever heard this TT with an air-bearing platter?

http://www.lumenwhite.com/mystere_uk.html

 

[dallasjustice]

DJ is Acourate "better" than the Spatial computing approach? Have you heard Spatial yet?

Last time I checked with Clayton he was using DIRAC. I doubt he's written his own software. Do you know anything about the filters or software, if any?

EDIT:

I just see a few screenshots from REW, Fuzzmeasure and Fabfilter on the website. If he's using PEQ filters generated from REW along with Fabfilter, I would say that's a pretty limited approach to DSP. I've done the same thing a couple of years ago. The problem with simple PEQ is that it doesn't handle phase/time. That's why impulse response correction software like Acourate, DIRAC and Audiolense are vastly superior.

 

[wisnon]

He was using Dirac, but then I heard he moved on. Not sure.

I dont know that much about this stuff, but i thought they all did time domain correction.