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Re: Re: MD v. DAT

Subject: Re: Re: MD v. DAT
From: Klas Strandberg <>
Date: Mon, 18 Aug 2003 11:11:28 +0200
Thanks Raimund, just one more question:

For how long back in time would you say the below judgements go?

I mean, it is quite inadequate to judge the specs of the single chip. As a
user, I have to judge about the whole assembly. Example: When your D3 worke=
d
fine in 1991, I know for sure how badly my own pc-soundcard converter
worked, regardless of poor shielding or not.

Klas.



Would At 12:21 2003-08-17 -0000, you wrote:
>Klas Strandberg <> wrote:
>
>>Thanks Raimund. What I would like to understand a bit is how good
>the simple
>>AD, DA converters in modern walkman type DAT's and MD's are. When
>using a
>>Portadisc compared to a cheap Sharp MD, what role does the AD, DA
>converters
>>play?
>
>I would say, that there are only minor differences between the AD
>and DA converters chips between the various devices. Today, these
>chips are very cheap (5 ... 20 $) and are generally of a high
>quality. However, the overall quality of a recorder depends also on
>other parts that will make the difference. Among these things are
>the pre-amplifier and the specific design of the recorder (e.g.
>shielding against internal digital noise). I still have not compared
>the Portadisk to the cheaper MD's. Besides my mini-laptop equipped
>with an external 24 bit audio interface, I'm still using a consumer
>DAT recorder SONY TCD-D3 recorder (purchased at about $600 in 1991).
>This old device still works satisfying for my purposes and I can not
>find any artifacts that could be attributed to its AD converter.
>
>>And the converters on cheap sound cards?
>
>The converter chips on cheap sound cards might be the same models
>than those in consumer MD recorders. Therefore, here applies the
>same I mentioned above. More important than the A/D converter itself
>is the shielding against digital noise and the noise performance of
>the pre-amplifier (even that of LINE-IN if you want to have the
>maximum possible dynamic range).  Especially the microphone inputs
>of cheap internal soundcards are often of a poor quality (certainly
>in laptop computers).
>
>>Will a typical cheap converter on a standard sound card make
>visible changes
>>on a sonogram?=A0
>
>No. However, it depends on the dynamic range that you wish to
>display on the spectrogram. Usually (e.g. for species identification
>or other sound parameter measurements), it is not required to
>display any signals below -60 dBFS. This level is far above the
>higher inherent noise levels of cheaper soundcards. Additionally,
>the potentially lower dynamic range of cheap soundcards will be
>masked by the environmental noise and the inherent noise of the
>microphone that is already present in a recording. If you want to
>display the full dynamic range of the recording (including the
>softest background noise) on a spectrogram, the higher inherent
>noise of cheap soundcards will become visible (but only if that
>noise is stronger than that of the original recording).
>
>>Would you say that cheap AD, DA converters cause more trouble than
>ATRAC and
>>MP3??
>
>No! Cheaper AD converters may add a very small amount of additional
>noise only (leading to a dynamic range of e.g. 85 dB instead of 92
>dB). There are no other significant distortions. The artifacts that
>occur in ATRAC or MP3 may lead to extremely degraded dynamic ranges
>of less than 20 dB at worst cases (which will of course never occur
>so extremely in common nature recordings).
>
>To my mind, the problem in ATRAC is, that the potential artifacts
>are highly unpredictable. Sometimes, the sounds will be recorded
>properly, but in some special cases you will get unreliable results.
>This is the reason why I always prefer DAT or other recording
>techniques without compression. I'm considering to buy the new
>PMD670, even if it has only a resolution of 16 bits. As we have
>discussed earlier, the limited dynamic range of a 16 bit system
>would be sufficient for most nature recordings...=20=20
>
>Regards,
>Raimund
>
>
>
>
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>
>
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