Thanks, J.C.
I smiled as I read that. Because, given that the "typical rock music" you are referring to, generally leaves the needle of the vu-meter near 0dB, and that, in the rare cases where there are enough moments of silence in this type of music (or Jazz), it is generally "unplugged", so it is close to the classical music.
In other words, parodying you, we do not feel the deterioration of Dolby when we do not really need it. On the other hand, they are very noticeable where it begin to be useful ;-)
In level matched and bias controlled listening comparison? If not, you should at least give that a try for objectivity sake.
Well put. I will add that, in my experience with Dolby in the professional world, SR is much less objectionable than is A, and the best engineers I know of disable it on tracks where dynamics are important, i.e. leave it off on the vocal track, but enable it on bass, guitar, etc. Either was preferable to DBX NR which had large dynamic artifacts. I have had the torture of transferring multitrack recordings with 24 rental DBX cards substituted for the Dolby A cards...not a recommended experience for anyone with hearing.
NR for consumer cassette was a totally different case, IMHO without it cassettes are decidedly lo-fi. DBX pumped and breathed like the devil and drove me crazy, Dolby B and Hi-Com were OK for pop music if both record and reproduce were carefully aligned, as was even more the case with Dolby C, the reason I never used it. Dolby S was more tolerant of eq and level tracking and really quite good, even for dynamic orchestral music when all the stars aligned, keeping in mind we are talking about a tape-based consumer delivery format. We were the development site for Dolby S, I still have the original Nak MR-1 I adapted with prototype Dolby S boards...it was a good sounding machine....for tape...but thankfully time moves on, as do our expectations for fidelity as superior delivery formats arrive!
Cheers,
Howie
ps. further regarding the nature of tape bias: in reality magnetic recording with AC bias resembles a sampling system, in that while the bias+signal field level is above the remanence level of the magnetic domain the actual domain orientation is in flux. Only at the zero crossings of the bias+signal will the recording be fixed. The bias frequency needs to be high enough that the system not run afoul of the Nyquist limit for desired bandwidth, too low bias frequency causes in-band IM between the signal and bias. Also, noise in the bias signal causes jitter in the sampling time base, so the bias signal needs to be extremely clean. This is why at 64x replication we used an 8 MHz bias system with high-bias line drivers which translates to 125 KHz at 1x audio.
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So all the measurements presented in their service manuals are done as an improvement in SNR at a specific frequency and they DO NOT get any closer to -115db...
Yet my best cd player had a max dynamic range of 100db and a max snr of -115 db , i had two of the best Nakamichi's and one of the best Pioneer(last and best version of dolby c), Technics (dbx), Tascam(dbx) plus several sony with dolby s and none of them at their best can give a PERCEIVED SNR and Dynamics any closer to my Denon Cd player while they had the last and most performant generation of dolby b-c-s.Dolby s is as quiet as it needs, but its Perceived Dynamics is lower that the 1991 cd player.
Without any noise reduction system there's no chance you can hear anything near to my cd player either.
Yet my best cd player had a max dynamic range of 100db and a max snr of -115 db , i had two of the best Nakamichi's and one of the best Pioneer(last and best version of dolby c), Technics (dbx), Tascam(dbx) plus several sony with dolby s and none of them at their best can give a PERCEIVED SNR and Dynamics any closer to my Denon Cd player while they had the last and most performant generation of dolby b-c-s.Dolby s is as quiet as it needs, but its Perceived Dynamics is lower that the 1991 cd player.
Without any noise reduction system there's no chance you can hear anything near to my cd player either.
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I know he used Branch and Appleby, Middlesex, Eng, to manufacture heads at least for the 1" C37.
Cheers
Alan
This would be meaningless, the random noise at any single frequency has a zero mean value. A lock-in amplifier or synchronous vector averaging of FFT's will eventually give you a huge SNR. I never used Dolby BTW, in the old days I had a Nak and always used the metal tape and was never bothered by the SNR. Everyone I made tapes for asked how did I get it to sound so good. I met Nak's chief design guru in 1988, spoke perfect English (rare at the time).
The same as i can evaluate what YOU pretend to the absolute truth...
Have you ever heard about this guy?
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Mark Waldrep In Trouble AGAIN | Audio Science Review (ASR) Forum
Exactly, you prove the point. The manuals do not specify any particular bandwidth for the s/n measurement, it is the weighted (or not) full bandwidth noise measurement. Let's presume that Sony TCK-333 has a s/n broadband of 61 dB with Metal tape, at 3 KHz for instance the actual measured noise level in just the critical bandwidth of say 350 Hz centered at 3 KHz might be (wild guess here) 85-90 dB or better.
And I agree without NR a cassette is rarely comparable to a CD player...
Cheers,
Howie
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There are actually real attempts to defraud at audio shows, surprise, surprise, surprise.
One of my friends went once to a tube freak show with a big and heavy black box. At the end of the show as nobody was allowed to know what was inside the box they listened to "the box".It was all WOWs and what an wonderful sound, what base and such silky highs and resolution , such a warm sound and all sort of bla bla's . He opened the lid after the show and inside it was a big heavy cooler for two LM1875 chips...
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