As some of us are in a different timezone no.
Anyway you have stated no interest in vinyl. So just trolling cos nothing on TV?
Anyway you have stated no interest in vinyl. So just trolling cos nothing on TV?
Would that effect their validity one way or the other (posted at 10PM (half time))?
Perhaps I'm mis-remembering, but I don't recall saying anything about 68 dB of dynamic range from vinyl records. 😕
My memory of those bad old days before the CD goes roughly like this: as far as cassettes went, around 40 dB S/N ratio with basic ferric oxide cassette tapes and no Dolby; around 50 dB S/N with Dolby B; and, in the 1990's, around 60 dB S/N with metal tape and Dolby S with HX-Pro.
And records? My recollection is that, as far as S/N ratio goes, they sounded pretty similar to the metal cassettes with Dolby S and HX-Pro used during recording. Maybe 60 dB, and to get there, you had to ignore all those ticks and pops and clicks that showed up even on the first play of a brand-new record.
I do remember making cassette recordings using metal tape and Dolby S, with HX-Pro turned on, and making recordings of my first few CDs. The cassette recordings sounded pretty similar to the CD's on playback - except for the noticeably increased hiss level, the annoying warbles and waverings of wow and flutter, and the progressive loss of treble over time as the tape aged.
Anyway, one thing I remember with crystal clarity: CDs were the first audio medium I'd ever heard with no audible hiss at any tolerable playback level.
I never got to hear one, but for a brief while, there were dBx encoded vinyl records. The audio went through a dBx compressor before being recorded onto disc; played back with a matching dBx expander, you got back all the original dynamic range, along with vastly reduced noise. I believe magazine tests of the day were quoting 80 dB signal to noise ratio on playback, with the dBx expander doing its magic.
-Gnobuddy
For digitising vinyl, you have the possibility of mathematically combining a half speed capture and a normal one to get the benefit of improved top end and at least reduced friction noise in mid range and top.
You could, but is there a need? Thinking aloud there if you get a cartridge with good LF response and you very carefully balance the arm/cart resonance you should be ok.
Thinking further, maybe half speed is not needed. I have noted that its the first track on an LP that is the noisiest and by track 2 or 3 things are a lot quieter. It might be that just a 20% reduction in rotation speed would do the trick for noise. All easy to speed and eq in digital
Thinking further, maybe half speed is not needed. I have noted that its the first track on an LP that is the noisiest and by track 2 or 3 things are a lot quieter. It might be that just a 20% reduction in rotation speed would do the trick for noise. All easy to speed and eq in digital
By combining the two captures, you avoid both LF arm resonance and HF cantilever/coil resonances and eddy current nonlinearities.
Also are the noise spectra the same when you run half speed? I suspect that the friction reduction might tilt the spectrum.
Also are the noise spectra the same when you run half speed? I suspect that the friction reduction might tilt the spectrum.
not sure the spectrum comes into it as its the level we are trying to reduce. However worthy of experimentation.
Not possible to sync two playings in reality. Try it some time for a fun surprise. This is also a good way to characterize speed stability.
I was giving myself a quick nightmare thinking about how one could possibly Kalman filter the two data streams in such a fashion that errors could be reduced.
This thread is all very academic to me, but I enjoy reading it. Welcome back, by the way, to Luckythedog. I was scratching my head about surface modifications for friction reduction, but very much going to defer to SY on this one, as my experience is minimal, at best. Would find it interesting to do see FFT plots of a record before/after an ultrasonic clean, and wonder what sorts of detergents folks are using in their cleaners. Wonder if something like Contrad 70 would negatively affect the vinyl. Certainly very good at removing environmental contaminants.
Nice flanging effects especially I suppose with belt drive. I found a VPI HW19 (fairly well regarded) to be 10's of msec off after 1/2 an album side after carefully aligning to a small lead in tick. I only tried the experiment once with a mono folk LP, even found that many ticks and pops were on the stamper by using two copies of the same record. Yes I thought that using correlation might reduce noise, gosh what a waste of time.
I realised this evening that I have in my possession two copies of the same album, both barely played that I would have no problem sacrificing for research either by my own hand or someone elses...
Kinda goes against the intent, no? Of course, that depends on one's goal. Might be worth it if you have some sort of extremely rare media that you want to preserve, but a huge PITA otherwise.
I certainly wouldn't do it on a regular basis, but for a record you want to rip where its be anal once then play many times I could do it.
Haha, okay, I was primarily focusing on how one could mix multiple playbacks of a record (at the same speed or at different to modulate tracking errors). Going for a full-blooded cleaning and wet playback before feeding your ADC certainly has some merit.
Anyhow, I don't want to discourage people from pushing the limits of the media, just doing a multiple-playback fusion is probably an exercise in futility. 🙂
Anyhow, I don't want to discourage people from pushing the limits of the media, just doing a multiple-playback fusion is probably an exercise in futility. 🙂
Yes it's totally hopeless to attempt to merge two separate recordings without sync. It's pretty well hopeless to merge them even with sync.......!
LD
Yes, and then you realize most of the noise is correlated anyway and it's just tape hiss (frequently easily audible over the surface noise).