RE: An Audio Fidelity Question

["Larry A. Lovering" <lloverin@genuity.net>]

Roger,

There is a significant physical size difference between an MP3 coded for
128, 160 or 192 and an MPEG-2 coded for "FM" quality.  But fidelity wise,
the difference shows up to me mostly on the listening device.  Headphones
and a "high fidelity" stereo system brings up certain perceptual artifacts,
some of which I believe is contributed by the MP3 player and the rest by the
coding format.  The CPU makes a difference too, in playback (faster is
better).  My work with PA equipment, typical mobile DJ stuff, won't let any
of my listeners guess as to the source, it isn't as high a quality as a
great stereo system.

I would love to do the same, and store my whole collection (some 4500
titles) on a hard drive and take it with me.  You would have to consider two
sound cards, if you want to do crossfades, and compatible playback software.
Right now, I use a laptop with BSI's Wavecart 3 to plug in effects, bullets,
and jingles that I feed to my mixer.  I record the wave files at 22k stereo
without MPEG compression, and have had some success using the Direct X
setting which allows for 8 or more simultaneous streams, so I can punch up
"carts" on top of each other.  With DJ equipment, there is no apparent
difference in the sound of the "carts" compared to the music on CD and
records (yes, I still use some of these, and that's primarily the reason I
want to go direct to hard disk instead of making more CDs out of these).

-Larry

> -----Original Message-----
> From: owner-boston-radio-interest@bostonradio.org
> [mailto:owner-boston-radio-interest@bostonradio.org]On Behalf Of Roger
> Kirk
> Sent: Wednesday, January 03, 2001 5:38 PM
> To: bri@bostonradio.org
> Subject: An Audio Fidelity Question
>
>
> This is not 100% radio-related, but given the vast
> plethora of knowledge, opinion and expertise
> embodied in our members...
>
> As a mobile DJ staying technologically current,
> I am planning to store music on Hard Drive in mp3
> format and I am trying to decide on what bitrate
> to use i.e. 128K, 160K or 192K.  The old size vs.
> fidelity dilemma.
>
> Have any of the members of this list participated
> in an A-B comparison test of compressed music?
>
> Supposedly, 1 in 10 people can detect a "difference"
> between uncompressed and compressed (mp3) music at
> 128K and 160K bitrates.  Most of the research I've
> read notes that critical listening with headphones
> highlights "differences" and that normal listening
> via speakers tends to diminish the ability to discern
> "differences".
>
> While mp3 is the most popular format, I'm willing to
> listen to alternatives.  I believe BSI uses mp2 format.
>
> Thoughts, comments, suggestions?
>
> You can reply off-list if you wish, but discussion
> my encourage lurkers to chime in.
>
> Thanks, in advance.
>
> Roger Kirk
> rogerkirk@ttlc.net
>
>
>
>