(17-Aug-2014, 16:41)f1eng Wrote: LPs are capable of recording above 20kHz, but not at very high level. It depends on the cutter head. The HF bit wears quite quickly too.
Some cartridges can pick up above 20 kHz. There is a massive difference between cartridges in this area. Some are chock full of resonances above audible frequencies, double digit distortion is common in the top audible octave, even in very expensive cartridges.
Some designers chose to roll the cartridge off early (this sounds best to me) some starting at 15 kHz some lower. Electrical characteristics of the phono stage and interference susceptibility of the wiring make a big difference at very high frequencies too. Thank goodness we can't hear them...
If you are seeing output above 40kHz it will almost certainly be 100% noise pickup from equipment not screened for this environment.
In terms of a CD and LP sounding different this is no surprise. The compromises needed for each medium are different, apart from the common recent choice to compress the hell out of everything so the sound is OK in a car and on ear buds in public.
If a CD and LP of the same basic recording sounded the same it would imply lazy engineering from the mastering engineer.
For LP the bass has to be mono, or the groove wouldn't be continuous. The signal to noise ratio is poorer so usually low level sound is amplified up a bit to keep it away from the noise. High level upper frequencies are limited if too high (this is not often necessary).
Mono bass is "good" since the power is shared between both amps and speakers and bass is supposed to be non-directional anyway.
Raising the low level sounds makes the detail easier to hear, which is a benefit too.
So there are two shortcomings of the LP manufacturing process which encourage the application of a "fix" which will sound nicer on every system.
Marcor which cartridge, phono cable and phono stage are you using?
Hi Frank,
my cartridge is an Air Tight PC-3
http://www.elusivedisc.com/AIR-TIGHT-PC-...o/AIRTPC3/
phonostage is the Devialet's one, cables are the standard cable that come with my SME V series tonearm.
Just a couple of notes. Not all the vinyl I did try to record come out like this. This particular one has a lot of brass in this piece and probably that contributes to the plot.
Yes there is a lot of noise. I am attaching a picture of the spectrogram, (not the plot) you can clearly see the noise and the resonance arriving up to the 96kHz but you can also see the sound going over the 50k. The spike you see match with the spikes in the dB (they are not tick).
Just to be clear I am not trying to make a point just sharing what I found. I am pretty pleased of how my gear sounds, i am just trying to understand a bit what is behind it.
thanks
Marco
