PDA

View Full Version : Wired or Wireless?



Ken Hokugo
2004-08-10, 20:53
Rod,

As I understand it, decreasing volume digitally means "drop" or "loss" of
bits. As a general statement, analog volume control is better than digital
volume control, as the former controls the volume by turning down the
voltage, thus the resolution of the signal should not be affected. Note
that I am not a techie and these are all I read somewhere else, but I guess
this is what the statement is trying to say.

Ken


From: "Rod Savard" <rodney (AT) savard (DOT) org>
Reply-To: Slim Devices Discussion <discuss (AT) lists (DOT) slimdevices.com>
To: "'Slim Devices Discussion'" <discuss (AT) lists (DOT) slimdevices.com>
Subject: [slim] Wired or Wireless?
Date: Tue, 10 Aug 2004 20:47:30 -0700

> Are you using the fixed or variable digital volume setting from the SB?
> Fixed is indicated for audiophile use.

I have a question about the Digital Volume Control on the squeezebox. I
don't really understand what this paragraph is saying on the web interface:

"You can choose to have the digital audio output on your player be fixed at
maximum level or be controlled by the volume buttons. If you choose to have
a fixed digital audio volume level, the analog outputs will have the highest
quality possible. With either setting, the analog output levels are adjusted
by the volume buttons."

How does setting the digital out to a fixed level improve the *analog* outs?
And why would someone care if they are using the digital output?

-Rod

Greg Patterson
2004-08-16, 11:49
I do not know what the Squeezebox is doing to change the volume with
the remote control volume control buttons but it is not necessary to
down-sample the data stream in order to reduce the volume. There is a
tool called Mp3gain for Windows that will normalize your MP3 files and
they clearly indicate that it is not a lossy procedure. You can, if
you stored the parameters, restore an MP3 file to its original volume
level and doing a bit for bit file compare should be equal.

On Tue, 10 Aug 2004 23:53:03 -0400, Ken Hokugo <khokugo (AT) hotmail (DOT) com> wrote:
> Rod,
>
> As I understand it, decreasing volume digitally means "drop" or "loss" of
> bits. As a general statement, analog volume control is better than digital
> volume control, as the former controls the volume by turning down the
> voltage, thus the resolution of the signal should not be affected. Note
> that I am not a techie and these are all I read somewhere else, but I guess
> this is what the statement is trying to say.
>
> Ken

Jacob Weber
2004-08-16, 14:29
That probably just means that Mp3gain doesn't touch the original file.
The gain change still results in loss of data, but it happens in memory
while the song is being played. This way it doesn't permanently change
the MP3.

Think of it this way: a digital volume change is just a multiplication.
When you multiply a whole number (e.g. 100) by a fraction, you might end
up with something like 66.66666666, with a lot of decimal places. There
may be too many decimals to store in 16 bits, which is what most digital
systems output. So you have to cut off some digits; thus, data is lost.

I'm not sure why the digital volume setting would affect the analog
outputs. It may be that the digital processing needed to change the
volume is done first, regardless of which output it's going to. Then
it's converted to analog for the analog outputs, but the "damage" has
already been done.

Jacob



In article <6c1855d4040816114971ed3d06 (AT) mail (DOT) gmail.com>,
Greg Patterson <gdavidp (AT) gmail (DOT) com>
wrote:

> I do not know what the Squeezebox is doing to change the volume with
> the remote control volume control buttons but it is not necessary to
> down-sample the data stream in order to reduce the volume. There is a
> tool called Mp3gain for Windows that will normalize your MP3 files and
> they clearly indicate that it is not a lossy procedure. You can, if
> you stored the parameters, restore an MP3 file to its original volume
> level and doing a bit for bit file compare should be equal.
>
> On Tue, 10 Aug 2004 23:53:03 -0400, Ken Hokugo
> <khokugo (AT) hotmail (DOT) com> wrote:
> > Rod,
> >
> > As I understand it, decreasing volume digitally means "drop" or "loss" of
> > bits. As a general statement, analog volume control is better than digital
> > volume control, as the former controls the volume by turning down the
> > voltage, thus the resolution of the signal should not be affected. Note
> > that I am not a techie and these are all I read somewhere else, but I guess
> > this is what the statement is trying to say.
> >
> > Ken