Nakamichi bliss!
 

Having been a touch blase about the recent so-called revival of the Cassette, last weekend I turned on our (much neglected) Nakamichi Cassette Deck 1 and played a late TDK SA90 (what else!) 1990s dub of a Joni Michell LP.

I had forgotten just how clean and airy this sounded. This was played through an Audion "Silver Knight " (single ended 300Bs) and some very high end Dyna-Audio floorstanders.

At medium volume levels I just could not hear any hiss, just an open and expansive sound. Wonderful!

And I did not even clean the heads - how tardy of me!

Or was it just too much Shiraz....

Views of this particular Deck and of using Cassette Decks with good valved equipment as a change from Vinyl?

Re: Nakamichi bliss!
 

The high end Naks were some of the best consumer cassette decks made. Not all of them were as good as that, but even the relatively cheap ones perform well. They made a serious attempt to cater for the mass market with the BX-100 series, which used a bought in Sankyo mech. The CD1 is also a Sankyo mech, and is a relatively late model.

There are inherent limitations to the cassette as a hifi medium, but good cassettes in a good deck can make amazingly good recordings, better than 3.75ips and almost on a par with 7.5ips using a typical 70s Japanese domestic R2R deck. You really need 7.5ips on a pro recorder to produce an obvious difference.

Re: Nakamichi bliss!
 

Yes the high end Naks did well to squeeze the last drop of fidelity out of cassettes, (I believe the Dragon had the lowest W & F of any deck) but that fidelity was only achieved with a deck in top condition, an excellent tape formulation and/or Dolby noise reduction, which itself required accurate alignment to avoid tracking errors.

The slow tape speed meant very short recorded wavelengths were necessary to capture the highest highs. 20 kHz was pretty much the upper limit of the tape and tape heads. There wasnt much in reserve, unlike 7.5ips open reel.

Also with such a slow tape speed and narrow tracks, tape dropout was always a potential issue, and (lesser known) Dolby NR exaggerated the dropouts. Then the azimuth errors...

But overall, cassettes were a fantastically successful format and deservedly so.

Re: Nakamichi bliss!
 

What is particularly impressive is that the technology went from being little more than a toy to a genuine hifi source in little more than a decade. The new Japanese tape formulations of the early 70s made a huge difference.

Re: Nakamichi bliss!
 

If playing tapes made on the machine on which they were recorded and the machine is correctly lined up, and if the heads are clean, etc. etc. the results from cassette can be astonishingly good, but, as one of the men involved with Dolby said at the time, the cassette is a fluke - everything has to be just so, and quite small maladjustments can affect performance severely. In my experience, this is particularly true of Dolby C.

One point I haven't solved to my entire satisfaction is whether cassette tapes lose enough HF with age to affect Dolby tracking, or whether the observed dulling at the top end is the result of incorrect line-up or oxide shedding. The NAD play trim feature struck me as a sensible real-world solution.

But when all's said and done, if it works, don't knock it. I picked up a Tascam 112 for next to nothing at the last Audiojumble. Leaving aside the vendor's risible claim that it "needs a mechanical line-up" - for which read a rebuild of the capstan control card - I found some cassettes I made many years ago, tried them and was surprised by how pleasant they were to listen to.

Re: Nakamichi bliss!
 

Ted, is the loss of HF with ageing an established fact? I have recordings made in the late 70s on Maxell/TDK stock which sound subjectively exactly the same as they did then. Of course, at 64 my hearing stops at about 12kHz so if the degradation is right at the top I may not be able to hear it.

Presumably it should be possible to demonstrate HF degradation in a lab using old reference recordings.

Re: Nakamichi bliss!
 

No, spontaneous HF loss isn't established beyond doubt by any means, although some video tapes show carrier loss, but that's a different argument. It's just an apparent problem I've had to deal with on occasion when transferring material, either by leaving Dolby off and playing with EQ, or applying HF correction before an external Dolby unit.

I well remember the excitement around cassette becoming a credible hi fi medium - it was indeed a remarkable and swift evolution, almost a revolution.

Re: Nakamichi bliss!
 

Yes hard to know the exact cause in a particular tape. As you say, it could be the recording was never lined up in the first place. It could be due to overbias, wrong pre emphasis, even just a dirty or worn record head.

I agree the NAD/Yamaha "play trim" feature was a sensible idea for consumers to try and correct mistracking but it was necessarily simplified. Left and right channels were ganged together and the adjustment of highs was limited, and could only help with mild hf mistracking. I've had to push it further with independent left and right channel adjustments, and generally more targeted corrections - which sometimes still aren't enough, and one has to abandon decoding, as you say.

My impression is that the techniques for attempting to get a Dolby encoded cassette to track correctly aren't that well known.

Re: Nakamichi bliss!
 

There's lots of high end cassette decks that were/are all capable of truly excellent sound quality. These include the high end machines from Tandberg, Revox, Pioneer, Onkyo, Yamaha, Technics and so on.

I once made recordings on my Revox A77 and the same on a 'mid priced' Technics cassette deck, I don't recall the model. When played back simultaneously and A/B'd from one to the other, I could not hear any difference whatsoever. However, just out of interest, I recorded test tones on both machines and you could hear dropouts and all manner of disturbances on the cassette deck, not so on the Revox. Which is strange given my previous statement. But of course, music is not a continuous test tone, it's a constantly varying complex signal and as such it suits the medium of compact cassette very well, certainly in the case of better quality, higher spec machines. SS music/data storage is fine and dandy, but there's something 'living' about electromechanical machines such as cassette decks and R-Rs that attracts me, and many others too.

Re: Nakamichi bliss!
 

There tends to be an audible 'crushing' effect with cassette recordings that you don't get with R2R, though there is a lot of variation between different tape stocks even on the same machine. I assume it's a combination of slow tape speed, thin oxide coating and narrow track width.

Re: Nakamichi bliss!
 

Back in the early 80's, I had a Revox A77 and a Technics cassette deck, a high end 3 head one. My friends all commented that the sound from the Revox was much better than that from the Technics.

Re: Nakamichi bliss!
 

Yes, with such small tape "real estate" to record on, the raw signal to noise ratio suffered. We could record at a higher level for lower noise but the penalty was more distortion, or we could do the reverse.

I find it interesting listening to cassette tapes I recorded back in the 70's. They have more distortion than I would nowadays tolerate (even on a cassette) . Perhaps part of the reason was that then in my 20's my ears heard highs (tape hiss) a lot clearer than they do now, so as a trade off I guess I put up with increased distortion for less hiss.

I remember reading a studio recording manual around the time Dolby NR started appearing. The writer observed that Dolby gave us a better signal to noise but it was the recordist's choice how to make use of it. We could opt for lower noise and the same distortion, lower distortion and the same noise, or settle for some noise reduction and some reduction in distortion.

With digital of course we're not forced to make such choices, but it's amazing today how often we hear digital files which are hard clipped, which is so unnecessary.

Re: Nakamichi bliss!
 

Psychology has a part to play. Everyone knows that digital systems have an absolute, abrupt limit where they clip hard rather than the softer characteristic of tape saturation. So people are very careful to make sure that digital recordings don't get to this limit.

On the other hand, there is the loudness war, where louder sounding recordings are seen as better selling than quieter ones.

Recording engineers are under a much stronger competitive imperative to go as close to the numerical limit as they can, but not over it, than they ever were in the analogue days. They also now have fancier processors to help them in this pursuit.

Plenty of people say they prefer the sound from analogue recordings, but simple calculations say that digital recordings ought to be fine.

Are these objectors to digital caused by:

1) Simply objecting because they know something is digital and peer pressure has told them to object even though there may be nothing objectionable.

2) Those simple calculations miss some factor that people can really hear.

3) The processing done to a recording to make it as loud as possible yet with absolute aversion to the numerical limit of the bit width. The digital medium itself actually being OK.


As far as the first one goes, I think some listeners are susceptible to group-think and feel they have to say what is expected of them. But this can't be all of them.

As far as the second one goes, it's easy to think that simplicity implies a lack of completeness and that some factors are missing. But some simple calculations are fundamental. 1+1=2 is a simple calculation. It doesn't get it wrong, it doesn't fail to mention that 1+1 is sometimes other values, because that isn't so. Maybe those bandwidth and dynamic range calculations are OK. Could we really have missed something?

The third one seems to me to have some basis. Recordings heading for a digital medium are treated differently. Could it be this which is objectionable? This mucking about happens up at the top end of the dynamic range which means it isn't hidden in noise, and the push for high average loudness means the recording will spend a lot of time up at the top end of the dynamic range.

So if new standards give more bits than the old 16 bit CD, then competitive pressures force everything right up to the new top end and the sound remains mutilated. The noise floor winds up dropping, but if it was already not a problem, no-one notices.

David

Re: Nakamichi bliss!
 

Back in the day, I was told that cassettes were better than open reel, because they had Dolby, 'metal tape', and all sorts of things.

I wasn't sold on their logic. All these things could be applied to an open reel format and benefit from wider tracks and higher speeds. They hadn't been introduced on open reel machines partially because they were less needed, and partially because the mass market had moved to the more convenient format at the time of their development, indeed, the move was the trigger for the development.

David

Re: Nakamichi bliss!
 

At the time, Angus McKenzie had his finger on the pulse of developments in cassette technology as well as anybody. When it came to time-shifting Radio 3 for his own use, what do you suppose he used?

Yup, good old quarter inch.

Re: Nakamichi bliss!
 

I don't know of Metal tape being used with open reel, although there was a late push for consumer open reel running "EE" tape which seems to have been a "chrome" formulation. Interestingly it was promoted for its ability to give similar fidelity as 7.5IPS at only 3.75 IPS. The Metal tape as you say found its niche in the slow speed audio cassette but also in camcorder formats (analog and later digital) where the greatest HF energy at the slowest tape speed was also paramount.

Re Dolby and Metal tapes, in the 90's I recorded a number of live band gigs in which I was a muso, onto ordinary Type I cassette but with Dolby C. I'm pretty sure I would have lined up the small recorder to the tapes at the time but for whatever reason, over 20 years later, I struggle to make the Dolby C decode even passably well. Perhaps with multiple playings, the cheaper low energy tapes have become partially demagnetised. I wish now I'd spend the extra dollars and recorded to at least Chrome (Type 2) cassettes.

Interestingly, towards the end of the commercially pre recorded cassette's run when CD's started to take over, many of the big labels switched to higher energy (Type 2) cassettes, although EQed for Normal (Type I ) playback. They used Dolby B encoding, as previously but also as source used a digital high speed master. So the consumer cassette was effectively a direct first generation analog copy of the studio master (like us dubbing from a CD to cassette) whereas previously it may have involved multiple analog generations. Many of these better cassettes also carried a very short series of full range test tones at the very beginning of the programme. I've digitised some well preserved examples of these and the test tones can extend in response out to a healthy 16 kHz, and the Dolby B can decode pretty well. So at the end of the pre recorded cassette's commercial life, it was better sounding than it had ever been, or perhaps ever would be. I believe these cassette were high speed duplicated at over 100 times normal speed on special Studer open reel machines.

Re: Nakamichi bliss!
 

Commercial cassettes started to sound much better when the duplicators started to use HX-Pro style variable bias technology.

On the other hand, there was a persistent problem with the choice of tape stock, at least in the European market. BASF were very successful in persuading duplicators to use their chrome formulations. These were high quality stocks, but had both lower noise and lower output than most tapes, and decks needed to be calibrated differently to use them properly, which almost none were. This resulted in serious Dolby B mistracking, the only solution being to turn the Dolby off on playback and put up with the companded high end.

Re: Nakamichi bliss!
 

Ah yes Dolby HX Pro. A great invention. I wish the high speed cassette duplicators I worked with had had it!

Re: Nakamichi bliss!
 

I never got Dolby C to work properly, by which I mean inaudibly, on cassette. For my money, it was a fluke too far. HX, on the other hand, was an elegant and effective innovation. EE tapes, as I recall, were a cobalt-modified oxide like TDK SA, which was a Type 2 ferric.

Re: Nakamichi bliss!
 

Dobly NR does require reasonable compatibility of alignment between the record and playback decks...for Dolby C, this often means rec and pb on the very same deck. Dolby B was a bit more forgiving hence most pre-recorded cassettes using Dolby B from the mid 80s onwards.

Case in point, back in 1990 I recorded a lovely David Bowie concert live on BBC Radio 1 onto a Sony HF-S cassette with Dolby C using an Onkyo cassette deck.
That cassette would only play back properly on the Onkyo...not the subsequent Namamichi or Yamaha decks that I had.

Fast forward to 2016 and I obtained another Nakamichi Cassette Deck 2 which I've given a thorough going over....and suddenly that Bowie recording comes to life with correct Dolby C tracking...sounds like the original broadcast to my ears which are still good to about 19kHz.

There's little doubt that ultimately RTR is better...my humble Akai GX210D can sound better than my Nak if W&F isn't too critical...but a truly decent cassette deck with a good cassette can be quite amazing given the limitations. RTR didn't really need the "jungle juice" cassette formulations...decent Fe2O3 was sufficient at 7.5ips to run rings around most cassette decks even using type II and IV cassettes. Though there were cobalt doped Maxell XL1 and the aforementioned EE tapes such as Maxell XLII produced in the early 80s.

I still use cassette and occasionally RTR to record from FM radio.