Minidisc recording compression

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"Ludwig77" wrote ...
>I have a minidisc recorder that I use to record live performances
> and band practices.

It would have been extraordinarily helpful to mention the actual
model number as your questions fall into some very gray areas
since a major re-working of MD technology by Sony.

> The MD recorder is a Sony and it has various forms of
> compression. The compression can extend recording time
> from the standard length of 80 minutes up to 30 hours.

Assuming you have one of the newer (Hi-MD) machines, yes the
shortest recording method is likely uncompressed ("linear PCM")
while the longer playing times are almost certainly compressed
ATRAC data.

See the minidisc community portal page at:
http://www.minidisc.org/index.html

And, if you have hi-MD, the FAQ at:
http://www.minidisc.org/hi-md_faq.html

> I'm wondering.... does this compression only affect the data
> or does it affect the sound being recorded?

The data IS the sound. Compression DOES affect the sound.
Thousands of man-hours of research has gone into making the
compression as "inaudible" as possible, but it is NOT perfect.

> In other words, is this compression like zipping and unzipping
> a .wav file on my computer where the data is compressed but
> the fidelity of the audio is preserved or is this compression more
> like MP3 where the sound is affected?

ATRAC compression is "lossy" like MP3. "Lossless" audio
compression like FLAC can only compress to a very limited
extent compared to ATRAC, MP3, Ogg, etc.etc.

Archived from groups: rec.audio.pro (More info?)

Ludwig77 <gregrjones@yahoo.com> wrote:
>I have a minidisc recorder that I use to record live performances and
> band practices.
> The MD recorder is a Sony and it has various forms of compression.
> The compression can extend recording time from the standard length
> of 80 minutes up to 30 hours.
> I'm wondering.... does this compression only affect the data or does
> it affect the sound being recorded?
> In other words, is this compression like zipping and unzipping a .wav
> file on my computer where the data is compressed but the fidelity of
> the audio is preserved or is this compression more like MP3 where
> the sound is affected?
> I haven't performed any A/B tests yet, but it sounds to me like the
> compression does affect the audio. I have a recording where I used
> the compression and the bass guitar sounds compressed because
> it distorts my speakers a little bit unless I tame the bottom end of
> the eq.
> I know the bass guitar wasn't as loud at the band practice that was
> recorded....


All MiniDisk recorders use ATRAC (Adaptive Transform Acoustic Coupling)
compression software. That is lossy compression. It depends on your ears
and the sort of music if you can hear it. Some people cannot hear a
difference between an MD and a CD. Others claim it is very noticeable. I
belong to the last.



Jens

Archived from groups: rec.audio.pro (More info?)

In article <1116419713.525430.90380@g44g2000cwa.googlegroups.com> gregrjones@yahoo.com writes:

> I'm wondering.... does this compression only affect the data or does it
> affect the sound being recorded?

The sound is directly related to the data, so yes to both.

> In other words, is this compression like zipping and unzipping a .wav
> file on my computer where the data is compressed but the fidelity of
> the audio is preserved or is this compression more like MP3 where the
> sound is affected?

Nope. It's a "perceptual encoder" that decides what you can't hear and
throws it away.

> I haven't performed any A/B tests yet, but it sounds to me like the
> compression does affect the audio.

Yes, it will. On some program material, its effect is quite obvious,
and on some program material (the kind that they like you to record)
it's pretty benign, but you can still hear a difference if you listen
carefully.

> I have a recording where I used the
> compression and the bass guitar sounds compressed because it distorts
> my speakers a little bit unless I tame the bottom end of the eq.

This is not likely a result of the data compression, but something
overloading somewhere.

--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo

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"Mike Rivers" <mrivers@d-and-d.com> wrote


>> I haven't performed any A/B tests yet, but it sounds to me like the
>> compression does affect the audio.

The highest quality ATRAC is essentially 256kbps and I'm sure you already
know what MP3 at that bit rate sounds like. ATRAC may be better than some
encoders and worse than others, but it still is highly compressed. I can't
imagine how anyone can honestly claim there is absolutely NO audible
difference between a 256kbps format and a 1.4mbps format. If so, they don't
know where to listen.

Julian

Archived from groups: rec.audio.pro (More info?)

In article <5f6dnVeiOrqgSxHfRVn-1A@comcast.com> JulianPAdamsNo@SpamHotmail.Com writes:

> "Mike Rivers" <mrivers@d-and-d.com> wrote
>
> >> I haven't performed any A/B tests yet, but it sounds to me like the
> >> compression does affect the audio.

No, I didn't write that. I haven't performed any A/B tests either, but
I fully believe that compression does affect the audio, and therefore
I won't use it for anything other than casual listening.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo

Archived from groups: rec.audio.pro (More info?)

"Mike Rivers" <mrivers@d-and-d.com> wrote
JulianPAdamsNo@SpamHotmail.Com writes:
>
>> "Mike Rivers" <mrivers@d-and-d.com> wrote
>>
>> >> I haven't performed any A/B tests yet, but it sounds to me like the
>> >> compression does affect the audio.
>
> No, I didn't write that. I haven't performed any A/B tests either, but
> I fully believe that compression does affect the audio, and therefore
> I won't use it for anything other than casual listening.

Opps. I thought that didn't sound like you!

Julian