MakeMineVinyl
Well-Known Member
[QUOTE="JeffMackwood, post: 214242, member: 133"
They say it right there...all measurements were taken at -20dB, and that says it all - and I noticed that even you missed highlighting it, fixating on the raw response number instead - just what manufacturers want people to miss. Mission accomplished for them. The problem is that the "-20dB" qualifier essentially disqualifies the whole measurement. It means the measurement was taken at a level that nobody would actually use in the real world.
Dolby or the lack of Dolby has nothing to do with the saturation limits of cassette tape, or any tape for that matter. The tape still cannot accept any frequencies above perhaps 5kHz at full operating level (0 VU on the meter on the front of the deck). All Dolby does is pack the dynamic range of the source somewhat within the limits of the tape, and expand it back on playback. That deck evidently had Dolby "C", which provided up to 20dB of "packing" and "unpacking". It lowered the noise by 20dB. The tape still has a native signal to noise ratio of around 45dB. Dolby C makes that 65 dB, but you still have to be extremely careful about overloading the cassette tape. It still won't record anything above around 5kHz at full level.
The lack of native dynamic range of cassettes is the crux of why cassettes are an extremely challenged medium compared to reel-to-reel tape, vinyl, elcaset, and especially digital. Dolby simply lowers the otherwise horrible noise of cassettes to something approaching passable.
The cell phone camera verses full frame DSLR issue we are seeing today is actually an good analogy. Cell phone manufacturers scream at the top of their lungs how great the on-board cameras are. That they are going to "replace" genuine DSLRs.
The tiny sensor on a cell phone camera verses the up to full frame (35mm film size) sensor of a DSLR are pretty good analogs of the available magnetic area available on cassette tape verses the much larger area available on open reel tape - the difference between their tape speeds increases this discrepancy.
Sure, cell phone cameras can take decent pictures which are OK for most people in most situations, but they do so with massive digital signal processing which takes the really crappy native dynamic range (to light) of the small sensor and processes the result into something passable.
A full frame DSLR doesn't need anywhere near this level of processing to produce an image with vastly wider dynamic range (the ratio of maximum darkness to maximum lightness). If you apply digital processing to that DSLR image, its performance is even better.
Nothing can change the laws of physics; a small camera sensor cannot possibly collect the number of photons which the much larger full frame sensor can. And thin, narrow cassette tape at 1.75 ips cannot possibly cram as much magnetic data onto itself as 1/4" or wider open reel tape running at 15ips. Signal processing helps, but its a band-aid at best. And in the end, consumers are misled, just as with cassettes.
"Record /playback responses (-3 dB limits), with Dolby C NR, using Nakamichi EXII tape: Dolby Lvl: 10.4 Hz and 20.5 kHz, -20 dB 10.4 Hz [/QUOTE]
They say it right there...all measurements were taken at -20dB, and that says it all - and I noticed that even you missed highlighting it, fixating on the raw response number instead - just what manufacturers want people to miss. Mission accomplished for them. The problem is that the "-20dB" qualifier essentially disqualifies the whole measurement. It means the measurement was taken at a level that nobody would actually use in the real world.
Dolby or the lack of Dolby has nothing to do with the saturation limits of cassette tape, or any tape for that matter. The tape still cannot accept any frequencies above perhaps 5kHz at full operating level (0 VU on the meter on the front of the deck). All Dolby does is pack the dynamic range of the source somewhat within the limits of the tape, and expand it back on playback. That deck evidently had Dolby "C", which provided up to 20dB of "packing" and "unpacking". It lowered the noise by 20dB. The tape still has a native signal to noise ratio of around 45dB. Dolby C makes that 65 dB, but you still have to be extremely careful about overloading the cassette tape. It still won't record anything above around 5kHz at full level.
The lack of native dynamic range of cassettes is the crux of why cassettes are an extremely challenged medium compared to reel-to-reel tape, vinyl, elcaset, and especially digital. Dolby simply lowers the otherwise horrible noise of cassettes to something approaching passable.
The cell phone camera verses full frame DSLR issue we are seeing today is actually an good analogy. Cell phone manufacturers scream at the top of their lungs how great the on-board cameras are. That they are going to "replace" genuine DSLRs.
The tiny sensor on a cell phone camera verses the up to full frame (35mm film size) sensor of a DSLR are pretty good analogs of the available magnetic area available on cassette tape verses the much larger area available on open reel tape - the difference between their tape speeds increases this discrepancy.
Sure, cell phone cameras can take decent pictures which are OK for most people in most situations, but they do so with massive digital signal processing which takes the really crappy native dynamic range (to light) of the small sensor and processes the result into something passable.
A full frame DSLR doesn't need anywhere near this level of processing to produce an image with vastly wider dynamic range (the ratio of maximum darkness to maximum lightness). If you apply digital processing to that DSLR image, its performance is even better.
Nothing can change the laws of physics; a small camera sensor cannot possibly collect the number of photons which the much larger full frame sensor can. And thin, narrow cassette tape at 1.75 ips cannot possibly cram as much magnetic data onto itself as 1/4" or wider open reel tape running at 15ips. Signal processing helps, but its a band-aid at best. And in the end, consumers are misled, just as with cassettes.
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