Cassette vs. CD?

An odd remark, really. Myself I play records around 90% of my listening time. That doesn't mean I accept some intuitive explanations of how digital audio works.
The reality is it's very complicated.

 

Analogue works just the same. There is NO difference between the technologies in how they treat signals. All information storage is band-limited, that means it has to throw out stuff above a certain limit. Records do just that. The laws of physics do not allow unlimited bandwidth.

 

"The less potent tapes showed a dB or so greater rolloff at 16 kHz and above, the ferric down 3 or 4 dB at the highest frequencies, while the Type 2 and 4 had strong energy to 20 kHz. It is worth pointing out that full waveforms can be reproduced by analog tape at these frequencies, something 44.1 digital is incapable of doing."

Per The Marantz PMD430: The Best Cassette Deck Ever Made? - Audio Ideas Guide Review

The Marantz PMD430: The Best Tape Deck Ever Made?

Date posted: March 15, 2007
"An AIG Online Exclusive I realized at the time, mid-1989, that buying this tape recorder and selling my Nakamichi CR7 would be viewed by readers and other audiophiles as sheer insanity. Now, more than 15 years later, I still have my PMD430, and yet another one to last me through my dotage. Don’t see many CR7s coming up on eBay any more, if any are still in use.

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But I’m not going to knock that once great machine. I come not to praise nor to bury CR7 (I’ll get to that later), but to marvel at the longevity of this little professional Marantz, many of whose siblings have toiled for decades in courtrooms and other places where accurate archiving is in order.

There were just two stereo models, the PMD430 being the 3-head version, featuring Dolby B and dbx noise reduction. The single-motor transport uses a belt-driven capstan system for low flutter, and while not bullet-proof, the mechanism has been reliable and unfussy. Record speed is very accurate, and variable playback speed allows tuning to pitch of recordings made on other machines. After I bought the second one (which was actually a CP430, made for the European market but otherwise identical), I had its speed synchronized by All-In-One Electronics tape-deck whiz, Boris, after he had made some other circuit board repairs earlier this year.

A few weeks later I decided it might be interesting to once again measure the original 430 along with the newly acquired one. I first ran curves in Summer 89 (Volume 9 #1), and was quite astonished, not just at the frequency response, but the fact that it would maintain those curves at Dolby calibration level, something no other cassette deck in my experience had ever managed. As I noted then, “As you can see, it is almost ruler flat, with just the slightest evidence of the beginnings of tape saturation above 15 kHz. What this tells us is that with this tape [TDK MA-X], especially if one switches in dbx and the limiter (both off for measurements here), it is almost impossible to drive this recorder into distortion.”

Would all this still be true? Well, measurement techniques have been refined over the years, and now I can simply hook up the recorder to my AudioControl SA3050 1/3 octave spectrum analyzer, fire up its pink noise generator, set levels, and put it into record. I chose 3 tapes of current vintage, a TDK MA 90 Type 4, Maxell XLS 110 Type 2, and Memorex dB 60 Type 1, planning to show results for all 3. But due to the virtually identical traces with all 3 (and a few other Fuji and other tape brands), and the difficulty of photographing the 1/3 octave measurements (follow the bouncing balls!), I opted to show just the one above, which is the TDK MA. The less potent tapes showed a dB or so greater rolloff at 16 kHz and above, the ferric down 3 or 4 dB at the highest frequencies, while the Type 2 and 4 had strong energy to 20 kHz. It is worth pointing out that full waveforms can be reproduced by analog tape at these frequencies, something 44.1 digital is incapable of doing. Note also that the rolloff at the lowest frequencies is partly the captured bounces of the “balls”, as well as some moderate slope in response.

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The deck shown above is my 17-year-old PMD430, but the performance of the CP430 (numbered with a 2, since they are visually identical right down to the vinyl protective case) was virtually identical after Boris’s cleanup and tuneup. In all those years, I’ve made many outdoor recordings with trains, loons, storms, and so on, as well as annual recordings of the Branksome Hall Girls School Christmas Carol service, and other regular concert recording gigs. In recent times, it has been a loyal backup to my various portable DAT recorders, as well as preserving many CBC Radio 2 concert broadcasts for continued listening. These days I use either almost exclusively in dbx mode, which maintains the extraordinary high frequency headroom (which Dolby doesn’t), as well as reducing noise by 30 dB without any audible consequence. Though I’ve heard dbx pump in other applications, especially when used for dynamic expansion, here it works perfectly, with no noise modulation that I can discern, either.

I you find this performance a little incredible (as in unbelievable), note at photo top that the record/play controls are down (on), the Pause button closest to the meters is not engaged, and the Monitor button below Record and Play is out (tape), all this clearly designating off-tape monitoring in progress. The Limiter button is also out (off), and the meters can be seen to read just a hair above Dolby level. Seventeen years and still performing at spec or better! And a well used (and well loved) portable deck at that!

I’ve owned open reel machines that don’t even come close to this at 7 1/2 IPS, and here we’re operating at 1 7/8 speed. My considerable experience with open reel machines has been less successful, most of them being very finicky for setup, prone to excessive head wear, and very choosey about what tape brands they will tolerate. Not so here. Also, like many other professional recordists, I’ve been hit by the bad binder problems of the 70s, and now have a closet full of 7 1/2 and 15 IPS tapes that demand head cleaning after every track to retain any high frequency response. Luckily this curse did not spill over into the cassette genre, which has proved to be a very robust medium. Most of my cassettes have retained their playback quality, even tapes that spent dozens of seasons in various nooks and crannies of my numerous cars. Would that CDs were so robust!

So, if I’m seeming a little optimistically nostalgic about Philips’s humble little invention of 40 years ago, it’s nice to be able to show the proof of its evolution into a true audiophile format in the 80s. In the case of the Marantz PMD430, it is an evolution of excellence that has endured into the 21st Century."