Item:
Location:
Price:
Item Condition:
Reason for selling:
Payment Method: Pickup - Cash, Paypal, COD Only
Extra Info:
 
Pictures:

 

 

• 
• Topic Starter
• Members
• 135
• 197 posts
• Location: Melbourne
• Country: Australia
• First Name:Eddie

• Report post
•  

Posted Tuesday at 11:21 AM

Just wondered, when playing an Tape should Dolby be on or off?

For me it depends on the tape and how it was recorded

This is testing my memory, but if you are playing back a tape that has not been recorded using Dolby you should not use Dolby for the play back.

 

If you are recording the tape for yourself, you should definitely have it on for record and for playback.

 

If you are recording for someone else, you should record it using the format they intend to use for play back.

 

Remember also that there are a number of different Dolby formats so you should match the Dolby record and playback formats.

 

Hope this helps.

No. This is both ways mixed it up depending on what sounds best during playback.............

Didnt like Dolby B and Dolby C wasnt much better. HXPro was good. I used mainly TDK SA and above, so didnt really have to use it.

36 minutes ago, Wimbo said:

Didnt like Dolby B and Dolby C wasnt much better. HXPro was good. I used mainly TDK SA and above, so didnt really have to use it.

Agree, with good tape no need- and a good deck

Using TDK SA on a Nakamichi 1000, my experience was that the recording improved through the use of Dolby B.  Sound preference is always a personal thing, but for me tape hiss always detracts from the music.  At the end of the day the amount of hiss depends on the quality of the cassette deck, quality of the tape and how good you are at setting the recording levels.

 

Again though, I haven’t used cassette tapes for a very long time.......

 

 If the Cassette deck can adjust the bias and equalisation to match the particular tape being used ,  Dolby  would track perfectly and  would work like a charm.  Most decent decks should be OK too. It's only when the cassette deck has inaccurate calibration that you really notice a performance drop off.  I guess its a case of try and see.

Good to hear Dolby off, my preferred chice to I most use a Nak RX303

I've still got some pre recorded tapes from the earlier 70's Led Zep and others that were not recorded with any dolby and it amases me how go they sound- better than later dolby tapes

 Adjusting the bias and equalization, if the deck has adjustments for those, is important for every recording.  Perhaps the most important adjustment for Dolby though (we'll ignore azimuth and stuff like that) is the recording level sensitivity.  Different brands and formulations have different sensitivity.  This is why recording a 0 dB signal on one tape might play back at 0 dB on one, but another tape might play back at -10 dB with the same recording level.  The recorded level and the playback level need to match or else Dolby will mistrack and will not sound right.  If one has a cassette deck that does not have recording level sensitivity (most do not), it's probably best not to record with Dolby on that deck.  If one does want to record with Dolby on those decks, they should find a brand and type of cassette that is calibrated in-sync with the cassette deck so that a 0 dB recording actually records at 0 dB.

It should also be noted that many cassette decks which do not have adjustment knobs for sensitivity will have internal calibration controls that can be adjusted if one knows what they're doing.  Also, systems like Pioneer's AutoBLE automatic calibration system makes it very easy to get the right sensitivity.  Of course, not all automatic calibration systems adjust for sensitivity.  Some just adjust the bias. 

I have found some one with a solution to this problem 

dave

• incurable tinkerer

 

This question has troubled me since my teens, and now in my mid life crisis, now that I am a grown up engineer, I am approaching a solution after several years sporadic research, and accumulation of 30+ tape decks...

Buffered audio is taken from the first gain / equalising opamp (bypassing all dolby chips) and goes in to the 8024 where a shelf boost can be applied if needed, then on to a discrete (i.e. no chips) dolby decoder. This actually sounds quite respectable, not necessarily like a cd but some really dull sounding cassettes can be made listenable, and the dolby tracking sounds OK. early days with this rig, but I have spent a few hours listening to it. Can't help wondering what it would sound like with a tube parametric, instead of a DSP (48kHz).

yes it is a crap medium but it can actually be very good, it is "tape". It suffers, like CD players with indifferent electronics that colour the sound.  In fact if you look at most, especially newer cassette deck's circuit, there is one little opamp in the corner for the playback, and the rest is all dolby chips (in the audio path). 

If you use Dolby B for recording, playback using Dolby B.

If you use Dolby C for recording, playback using Dolby C.

If you use Dolby C-HX-Pro for recording, playback using Dolby C or C-HX-Pro.

This is the same for any noise reduction system that uses a record / replay process like JVC's ANRS, Aurex's ADRES and of course dbx

 

Playing back a Dolby recorded tape with the appropriate Dolby playback mode will result in an artificially emphasised treble similar to playing back Type 3 (CrO2) or Type 4 (metal) tapes on the Type 1 (standard Ferric Oxide) tape setting.

 

I suggest the OP does a bit of reading on the Dolby system to understand how it works.

 

Agree with the responses regarding tape types, boas optimisation and replay calibration for different tape sensistivities.

 

Cheers,

Alan R.

 

 

Dolby NR, when used under the correct circumstances, should not muffle the music.  It should reproduce it accurately.  Sometimes people think it's muffling the music because playing a Dolby B encoded tape without the Dolby sounds brighter with more treble, but that is an artificial treble boost.  The encoding process boosts the treble, but then the decoding process will decrease it to where it should be for accurate sound.  Well, at least as accurate as one could expect given the flaws with cassette tape and analog recording in general. 

This artificial boost was viewed as being desirable by some people.  If people want to play back their tapes that way, well, fine I guess.  Perhaps it can help in situations where the tape, cassette deck, or speakers have poor treble response to begin with. 

Dolby C was a very unforgiving option.  It was more aggressive at reducing hiss and it also had built-in anti-saturation properties, but Dolby C needed even more ideal calibration on both the recording and playback decks than Dolby B.  Also, playing Dolby C tapes without Dolby C on playback sounded quite terrible.  I think this is a big reason why Dolby C really wasn't used by a lot of people.

Dolby S, which came out in the 1990s, was probably the best implementation of Dolby NR on consumer decks.  Dolby learned their lessons and were tired of their reputation suffering because of poor quality or poorly maintained cassette decks.  I believe they required deck manufacturers implementing Dolby S to have some kind of automatic calibration function so that the settings wouldn't be so wildly off to create certain Dolby mistracking.  Dolby S tapes can be played back without Dolby or using Dolby B without sounding terrible.  That gives it a big advantage over Dolby C.  Unfortunately, Dolby S came out when cassettes were already falling out of favor and the heightened deck requirements meant that it only showed up in more expensive decks.  I had (well, have, but it does not work at the current time) a Kenwood Dolby S deck that was brought new in 1995 and I can say that Dolby S does work well.

When I do record, which I still do on occasion, I generally do not use Dolby NR.  If I wanted clean sound, I'd just use digital recording.  When I record on cassette, I purposely want the "cassette sound."  Plus, although I have some very fancy decks including 3-head ones and a Nakamichi, none of them have sufficient adjustments on the front-panel for the proper calibration that Dolby needs.  I have a couple of decks with auto-calibration, but both of those are auto-reverse decks and I really can't say for sure that the azimuth is right on with those decks as it's harder to adjust the azimuth on auto-reverse decks.

One final note.  Tapes can lose a little bit of their recording levels over time.  In theory, chrome tapes are supposed to be better than ferric/ferric-cobalt tapes at retaining their levels, but I don't find this to be the case in my experience.  The true chrome tapes I have have lost more of their signal than the regular ferric Type I and "pseudo-chrome" ferric-cobalt Type II tapes I have (most Type II blank cassettes were ferric-cobalt tapes and not chrome tapes even though people referred to them as chrome tapes).  This might be because chrome tapes are not as durable in high heat.  Anyway, the point is that tapes might track for Dolby correctly when newly recorded, but they might mistrack as they age due to signal loss or cassette shell warping.  That said, I have a lot of 30+ year old cassettes on cheap type I tape that are still playing back at the levels they were recorded with years ago.

I never used Dolby B or C to record nor playback on my own recordings as i always bought good tapes where hiss was rarely an issue so the recordings didn't need it. I would use B on playback of pre recorded tapes as their quality was all over the place, some brilliant, some woeful. Since owning a couple of Teac decks with Dolby S though i use that setting for recording and playback especially as modern tapes can be hit and miss regarding quality. The Dolby S tapes are also played back in the car on an old Becker Mexico that only has B capacity but they don't suffer for not using any noise reduction as the car is an old BMW with rather ordinary speakers anyway and a sports exhaust that doesn't lend itself to critical music listening.

 

Interesting discussion. I know the vast majority of my friends in the 70s and 80s would turn Dolby off for playback as they thought it muffled the treble. But they were nearly always rubbish recordings on crap tapes anyway with the idea of cleaning the heads never entering their minds.

I agree with the above posts - if the tape was recorded using a noise reduction (eg. Dolby B ) it should be played with the same noise reduction.

 

Back in the cassette days, I always recorded/replayed with Dolby B.  I know many purists don't like what Dolby B does to the sound, but on the equipment I had I couldn't notice any defects.  Now I have much better equipment I might be able to notice the difference. 

 

However, here is a historical exception to my rule "play back with the NR which the tape was recorded".  I put a cassette player in my first car, and back then not many car units had Dolby, and as my unit was inherited from a friends' upgrade it certainly didn't have it.  So I could only play back my Dolby recorded tapes without it.  But, because this was a bottom-level player and my speakers were very ordinary, I didn't notice any treble boost.  The system had such a poor high-end that any treble boost from the Dolby recordings actually compensated for the hardware's limitations.  Not to say it sounded good - it was a cr*p car system, but sounded much better than the standard AM radio that initially came with the car. 

 

 

Was it a Eurovox deck by chance

An alternative to Dolby was Toshiba's (Aurex) Automatic Dynamic Range Expansion System (ADRES).

It is a record replay system for noise reduction developed by Toshiba to improve the signal to noise ratio and the dynamic range of compact cassette tape systems.  It was slightly inconvenient that it relied on the recoding of a 1kHz calibration tone at the beginning of the tape so that the replay system could use this to calibrate the decoder to compensate for differing tape sensitivities.  This replay calibration adjustment was required to ensure the replay decoder tracked the signal on the tape correctly so that the reproduced audio was accurate in terms of preserving the originally recorded dynamic range during playback.

 

Some Toshiba and Aurex decks had ADRES encoders / decoders built in along with Dolby B.  They also marketed stand alone add on units for use with existing decks.  I still own an Aurex AD-2 unit which I use to playback cassettes I recorded using ADRES, but it works just as well with my TASCAM reel to reel deck with superb results.

 

Unlike other popular domestic noise reductions systems of the day which included Dolby B, JVC's ANRS (Dolby B clone) and dbx; ADRES offered a superior noise reduction capability with lower harmonic distortion as the peak recorded level (if the system was set up correctly) was nominally at the -3dB VU mark compared to other systems at 0dB or +3dB reference points.  Using a lower reference level and keeping the peak recorded level lower meant that tape saturation due to excessively high recording levels was unlikely, thus reducing distortion and lowering replay mistracking considerably.  The other advantage was the frequency response was dictated by the native non-NR performance of the deck used.  ADRES did not compromise the frequency response of the system, just significantly improved the signal to noise ratio.  So typical noise improvements using ADRES were as follows -

• 17dB @ 100Hz
• 20dB @ 1kHz
• 30dB @ 10kHz

The performance of dbx systems was at the time superior to Dolby B, but the drawback was the "breathing" sound you could hear on some musical material as the level changed rapidly.  This was never evident with ADRES.

 

In cassette decks I found that TDK AD-X tapes delivered the best bang for your buck.  Although TDK Metal tapes were the best the cost of the blank tapes didn't justify the performance.  Also, not all decks supported the recording of metal (Type IV) tapes.

 

ADRES was never popular outside of Japan although the decks and NR units were marketed around the world.  In Japan pre-recorded ADRES cassette tapes were available and would you believe even ADRES encoded LPs !

 

Cheers,

Alan R. 

 

 

On 27/09/2018 at 12:21 PM, Monkeyboi said:

...Unlike other popular domestic noise reductions systems of the day which included Dolby B, JVC's ANRS (Dolby B clone)...

I'm curious, how similar was ANRS to Dolby B?  I recall when looking to buy my first cassette deck I came across JVC decks, but was wary to get ANRS when Dolby B was the consumer industry's standard. The salespeople told me that "it was the same", however, not all salespeople are totally honest.

 

 

Edited September 28, 20187 yr by audiofeline

8 hours ago, audiofeline said:

I'm curious, how similar was ANRS to Dolby B?  I recall when looking to buy my first cassette deck I came across JVC decks, but was wary to get ANRS when Dolby B was the consumer industry's standard. The salespeople told me that "it was the same", however, not all salespeople are totally honest.

 

 

AFAIK, JVC didn't want to pay the Dolby license fee so they developed ANRS which was for all intent the same as Dolby B.  So much so that Dolby B encoded tapes could be played back on a machine using ANRS and vice versa without any audible difference.

There was a discussion about it here http://www.tapeheads.net/showthread.php?t=36251

 

Cheers,

Alan R.