DAB vs FM

[Stuart]

Yep, kind of what I was saying, with added science! I do think there are some aspects of the sound of a cassette recording of an FM broadcast made in the 80s (even after digitisation to 256-320kbps vbr mp3) which sound better than most current FM/DAB and that is nearly all down to the relative lack of dynamic range compression plus (in the case of DAB esp. 128kbps) lossy compression. Dave McCarthy in this very list explained how they used to experiment at the BBC with Optimod in the late 80s/early 90s which totally flattened the sound (and would let it run into distortion during loud passages until the levels were brought down in a delayed fashion). And why, even on my Pure portable, some internet stations sound better than any DAB and FM stations, the dynamic range trumps any slight loss of information compared to FM, and in any case many internet stations use better bitrates than DAB.

Some analogue audiophiles would claim that the 44khz CD-rate sampling is not enough to capture the full waveform at higher frequencies...

It is very disappointing that a serious music digital-only station partakes in the loudness war .... perhaps time for a campaign?!

Incidentally, this getIplayer thingy, is this accessing a different stream to proper iPlayer that it has higher bitrates? Or is it only how it is re-encoded?

Stuart

--- In peel@yahoogroups.com, "Tim" <lyrasbench@...> wrote:
>
> 
> The web version of 6music is 128k aac @44K1, satellite broadcasts are 160k @48K. I just looked at the waveform for both transmission types when doing some archiving of a session and it's virtually identical down to sample level.
> 
> It's a very moot point as to whether this is more or less lossy than FM, both analogue and digital have a frequency cutoff at about 15kHz, where digital scores over analogue is that you don't tend to get noise introduced by interference, and obviously in most cases analogue FM has been recorded in the past onto analogue cassettes or tape, and even if direct to DAT or CD it's going via some sort of analogue subsystem which will introduce losses. This is the funny thing about analogue buffs - what they see as "warmth" in analogue formats is because their equipment introduces filtering (losses) at various stages, where digital signals have much less before they hit the analogue chain and so have more higher frequency components due to allowing very sharp edges.
> 
> What really screws up all sorts of radio these days is overuse of compression and hard limiting to decrease dynamic range. Basically everything is turned up when quiet and limited when loud, and the result is very loud and harsh - this is a modern fashion aimed at making the broadcasts sound uniformly loud. If you look at the waveform for a radio show broadcast on 6music, you'll find it's pretty much at maximum amplitude all the way through, where something recorded in the 1980s has a lot of dynamics.
> 
> 
> --- In peel@yahoogroups.com, "Humphrey" <thebarguest@> wrote:
> >
> > The current BBC6 web-broadcast quality is pretty good, and compares well to the old FM. The former uses AAC (advanced audio codec) at a variable bit rate which can go above 200 kbps (at 44 kHz). Up until a few years ago, however, the quality was awful - 64 kbps and even lower. FM is/was equivalent to 192 kbps (I think I read somewhere), which is of course "lossy". I recently discovered to my surprise that some audiophiles regard cds as "lossy" and prefer vinyl ! I'm not sure my 50-year-old, rock-battered ears could tell the difference between 192kbps and a CD, ha ha ....
> > 
> > --- In peel@yahoogroups.com, "Stuart" <stuartb@> wrote:
> > >
> > > There's no excuse for less dynamic range on DAB after all we were always
> > > told the compression on FM was to avoid the hiss taking over in poor signal
> > > areas during quiet passages. DAB and other digital sources should be using
> > > the full dynamic range that we all seem to be supposed to cope with on CD
> > > and DVD audio. And many internet radio stations are now in far better SQ
> > > than DAB due to not using dynamic range compression. And while Radio 1 does
> > > have the "excuse" it broadcasts on FM and so some studio-stage compression
> > > takes place, 6music only broadcasts digitally so should use CD style
> > > uncompressed  (dynamic range wise)
> > > 
> > >  
> > > 
> > > The bit rate is another matter.. Radio 3 does get the full 192kbps and R1
> > > 160kbps but 128kbps is rather poor for a serious music station.
> > > 
> > >  
> > > 
> > > Incidentally I find the current FM Radio 1 quality some way below the best
> > > of my early 1980s Peel show mixtapes...
> > > 
> > >  
> > > 
> > > Stuart
> > > 
> > >  
> > > 
> > >   _____  
> > > 
> > > From: peel@yahoogroups.com [mailto:peel@yahoogroups.com] On Behalf Of
> > > lollygagger
> > > Sent: 04 June 2012 15:56
> > > To: peel@yahoogroups.com
> > > Subject: [peel] DAB vs FM
> > > 
> > >  
> > > 
> > >   
> > > 
> > > Hi All
> > > 
> > >  
> > > 
> > > I don't pipe up much...having been seemingly spoilt with Radio 1's FM
> > > quality for Peel's shows then found I had to search out radio shows for
> > > tracks that Peel would have likely played i.e. Giles Peterson then Hew
> > > Stephens (more white boys with guitars) and Rob Da Banks low key left of
> > > centre of music...and some internet listening from dadelionradio
> > > 
> > >  
> > > 
> > > When Giles left Radio 1 to DAB Radio 6 128kbs...what a come down in sound
> > > quality where have the dynamics gone! On the plus side I have discovered
> > > that Tom Ravenscroft does appear to have weekly slot on Radio 6...yeh I am a
> > > bit slow to pick up on these things.
> > > 
> > >  
> > > 
> > > What a shame though Radio 1 gets FM to play mainly regurgitated X factor
> > > music. Music lovers with a variety of tastes, who do notice the difference,
> > > get low fi 128kbs...grrrr.... just my gripe.
> > > 
> > >  
> > > 
> > > Gordon
> > >
> >
>