In article , Dave Plowman (News)
wrote:
In article , DAB sounds worse
than FM wrote:
Whenver I've compared R3 DAB with R3 FM, FM has always sounded better.

Download and listen to the R3 DAB and FM recordings from my samples
page:

http://www.digitalradiotech.co.uk/di...es.htm#samples

Just have done. Apart from one being MP2 and one MP3, there are splats
on the DAB sample which you simply don't get in reality, and some form
of heterodyning on the FM one which I've never heard before. Sounds like
a possibly dodgy land line? Or something going on at low level in the
recording which is well and truly upsetting the coding - as it shows up
on the DAB sample as well, but in a different way.

Perhaps Jim Lesurf would have a listen and comment?

Afraid that at present I don't have/use any MP2/3 software. To listen I'd
have to find suitable software, check it worked OK, burn the results onto
CD, and then do a comparison listen.[1] Afraid that this isn't something I
have time for at present, although I am interested in doing it at some
point. I don't listen via computer as the results I'd expect don't seem
worth the effort to me.

[1] This would also raise all sorts of other issues like rate conversions.
Plus the snag of any FM comparison being via a MP2/3 rather than plain
LPCM.

Low level heterodyne noises may be caused during the RX and recording
process, particularly with FM. If they appear on both FM and DAB we'd need
to know more about the recording system to guess what their cause might
be...

If someone has *two* DAB radios with digital outputs, and a card that can
read in from them, I'd be interested to see if they produce the same bit
streams, though. Ditto for a pair of DTTV receivers. Alas, I only have one
DTTV RX and no DAB. Nor do I have a computer card that can read in two
s/pdif streams. However I have on my 'to do' list a 'bit output'
comparision of two DTTV boxes using a fast sampling scope to grab the
bitreams in parallel.

Slainte,

Jim

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