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The1FastCar
2004-01-04, 19:31
How does the Headphone out sound when connected to Good headphones?

-----Original Message-----
From: discuss-bounces (AT) lists (DOT) slimdevices.com
[mailto:discuss-bounces (AT) lists (DOT) slimdevices.com] On Behalf Of Jason
Sent: Sunday, January 04, 2004 8:19 PM
To: 'Slim Devices Discussion'
Subject: [slim] MP3 quality poor due to low volume levels,
notcompression.


One more thing I failed to emphasis in my previous post. The DAC in the
squeezebox is rather mediocre. In fact it's pretty pathetic. In A/B
testing between the analog outputs and digital output on the squeezebox
there is no comparison, the digital output to my integrated amplifier
sounds substantially "beefier".

-----Original Message-----
From: discuss-bounces (AT) lists (DOT) slimdevices.com
[mailto:discuss-bounces (AT) lists (DOT) slimdevices.com] On Behalf Of Simon Turner
Sent: Sunday, January 04, 2004 4:53 PM
To: Slim Devices Discussion
Subject: [slim] MP3 quality poor due to low volume levels,
notcompression.

Yes, but what can i do?
The sound of the MP3s from the Squeezebox and the iPod is thin and
lacking in oomph even when the amp is turned up a lot. In addition
sometimes I like to listen to music really loud. This is not a problem
with the tuner, tape or CD.. but it will not go loud enough to hear the
MP3s at house-shaking volume. With my test MPs's volume at 6db above
clipping the output from the Squeezebox appeared to match the CD, the
quality appeared no lower than i would expect (well, I couldn't hear any
horrible distortion at least) and I got all the bol**** from the sound I
require. The only problem the is how it sounds in the iPod's
headphones... :-(

Simon

-----Original Message-----
From: discuss-bounces (AT) lists (DOT) slimdevices.com
[mailto:discuss-bounces (AT) lists (DOT) slimdevices.com]On Behalf Of Jason
Sent: 04 January 2004 23:32
To: 'Slim Devices Discussion'
Subject: [slim] MP3 quality poor due to low volume levels,
notcompression.


You are going about this the wrong way. To adjust the volume to
equalize your mp3 volume and your CD volume you should be turning the
knob on your amp, not cranking up the level with mp3 gain.

-----Original Message-----
From: discuss-bounces (AT) lists (DOT) slimdevices.com
[mailto:discuss-bounces (AT) lists (DOT) slimdevices.com] On Behalf Of Simon Turner
Sent: Sunday, January 04, 2004 3:54 PM
To: Slim Devices Discussion
Subject: [slim] MP3 quality poor due to low volume levels,
notcompression.

When I started this thread I did not really expect any answers, but have
returned from a few days away to find a wealth of information to trawl
through. Thank you to everyone who replied. I don't really want to
restart the thread but I have to clarify a couple of things, add a
couple of things I omitted and post the results of some (very
unscientific) testing I did yesterday.

First off. I originally started using MP3Gain because many of my MP3's
sounded quite distorted when played via headphones on my iPod. I found
that the distorted files always registered as clipped by MP3Gain
(incidentally the distortion was most noticeable on modern highly
compressed and loud music such as psytrance). When I used MP3Gain to
reduce the db level to that below clipping the distortion disappeared.

Secondly.. when I said ripping, I usually meant encoding. Sorry. It is
the encoding that appears to introduce the clipping, not the ripping.

I can't hear the distortion via the line-out of any other devices (e.g
cheap CD based MP3 player, iPod, Squeezebox, PC sound card) unless I
increase the gain considerably above clipping level (about 6db or 8db or
more perhaps).

When I say the sound is thin and weedy (I think Jason asked) I meant the
sound is vapid, lacking oomph (or boll**** as we might say in the UK), a
bit powerless, not very dynamic. The amplifer I am feeding the
analogue-out of the Squeezebox into is an integrated amplifier (i.e.
with both pre-amp and
power-amp) and i assume that the input (pre-amp?) is not being run
correctly. As an indication.. normally i might have my amp power know at
about thirteen minutes to the hour, with the Squeezebox i need it just
past the hour. If I used the CD at just past the hour setting I wouldn't
be able to hear the telephone and after a while the neighbours might
complain. I am not using a receiver, as someone assumed. For me a
reciever is a radio. Due to Jason's post I am now wondering if what I
mean by weedy is due a reduction in dynamic range caused by reducing the
volume of the file to below clipping level (as indicated by MP3Gain, not
necessarily 89db).

Testing:
I tried three different integrated amplifiers, a Nad, a very old Trio
and a Harman Kardon. The results were the same on all so I've not
differentiated below. I used a Harman Karden CD Player as reference.

I used a CD of a couple of particularly kick drum driven techno songs. I
ripped these songs to MP3 and made copies of them, adjusting their
volume levels in MP3Gain (in steps of 1.5db). I then played these back
via the Squeezebox and the iPod to see how the volume levels compared
with the original CD.

The original file did not register as clipping by MP3Gain. An adjustment
of 1.5db introduced clipping To achieve the same volume level as that
produced by the CD player I had to adjust the volume level of the files:
iPod: +4.5db
Squeezebox: +6db.

The iPod does not have any volume (or eq) adjustment for it's line-out.
The Squeezebox was set to max by the remote. The file with the 6db above
clipping volume sounded horrible in my iPod headphones and also a bit
yucky in the Squeezebox headphones. However, no distortion was
noticeable via the line-outs.

For me format is not an issue. MP3 is the one I am stuck with. Using the
Digital-out is not possible as I have decided that I will buy a good
quality hifi system (not an AV system, it'd be stupid as I don't really
watch any TV, videos or DVDs!) and that the price of DAC's is too high
to consider buying one. So.... I an still not really any nearer
resolving my problem than I was at the start when I originally made my
post despite all the useful and illuminating replies. I am beginning
think I may increase the volume of all my MP3s and sell the iPod
(although it looks nice, when you have most of your MP3 collection
ripped using 320 CBR or --alt-extreme the battery life is laughable,
only 4 cds sometimes!). Hopefully I'll find another personal MP3 player
with a similar audio quality that will not distort (anyone tried the
Dell one?).

Anyway. Thanks again for all the replies.

BTW. I've never considered myself an audiophile before. I just like loud
banging music!

Simon
Brighton UK

















-----Original Message-----
From: discuss-bounces (AT) lists (DOT) slimdevices.com
[mailto:discuss-bounces (AT) lists (DOT) slimdevices.com]On Behalf Of Rob Studdert
Sent: 02 January 2004 15:08
To: Slim Devices Discussion
Subject: [slim] MP3 quality poor due to low volume levels,
notcompression.


On 2 Jan 2004 at 8:17, T wrote:

> Well, as I previously stated, there is NO clipping introduced
> (verified by various measuring equipment), despite the fact that
> mp3gain claims there
is. If
> it can't be measured, it's not there. And, if the equipment is
> designed correctly (and I've been doing it for 5+ years), a 0dBFS (or
> any other
level
> signal) will exit the decoder at exactly that level with no clipping.

Of course nothing exits the digital I/O at greater than 0dBr, it's the
calculated dynamic overshoot that's clipped.

> Actually, the ARE designed to accomodate the 'technicians top forty',
> as that is what they are primarily used for in the professional world
> (i.e. program distribution from studio to transmitting station).

I've only been in the game for 20 years and freq runs/test tones are oft
referred to as "the techs top forty", not real world dynamic audio.

Rob