tony sayer wrote:
> In article <h218qh$bq1$1@news.eternal-september.org>, Fredxx
> <fredxx@spam.com> scribeth thus
>> "Ian Smith" <news0807REMOVECAPS@orrery.e4ward.com> wrote in message
>> news:YvidnZyq4cW7f97XnZ2dnUVZ8kudnZ2d@brightview.c o.uk...
>>> DAB sounds worse than FM wrote:
>>>
>>>>
>>>> In other words, you live in a crap FM reception area.
>>> There is some truth in that.
>>>> Reception quality is different to audio quality, and anybody who has
>>>> reasonably good reception quality on both DAB and FM will receive higher
>>>> qulaity on FM.
>>> Well, most people don't agree with you. Whether they are discerning or
>>> not, I don't know.
>>>
>>> I don't agree with you in terms of quality. I have an excellent sound
>>> system and I've never managed to get anything that gets near hiss-free on
>>> FM.
>>>
>>> This is very much like the vinyl v CD discussion. Vinyl have me crackly
>>> playback, oven on a good deck and with a new pressing. CD gave me click
>>> and pop free playback - no matter what any HiFi mag says, the 'quality' of
>>> my CD experience is higher.
>> On paper the CD should be miles ahead of vinyl. Most CDs uses 2 channels
>> of 16 bits at 44.1kSamples/sec. There is no sompression so there are no
>> artifacts. The data rate is an astounding 1.4Mb/s. 16 bits give 72dB audio
>> range which is better than my ears.
>>
>
> I remember once being given a demonstration of Vinyl-v-CD by Derek
> Scotland of Audiolab fame.
>
> I was amazed at how good he got the Vinyl to sound, and that it seems
> was due to the right equipment and some Japanese pressings. OK not quite
> the same in terms of distortion and absolute signal to noise ratio but
> very impressive indeed;!..

Early D to A chips suffered from 'crossover distortion' (actually MSB
inaccuracy). That was one reason for the myth of 'CD sounds worse'

By the early 80's that was all history.


>
>>> Likewise, the 'quality' of my DAB experience on radio 3 is higher than I
>>> could have ever achieved with FM (in any location I've ever tried it).
>>> Arguments about R4 speech radio in mono being compared to FM are just
>>> futile and don't relate to any real user experience.
>> It's easy to show that performance of FM is generally superior to DAB,
>> however it just goes to show how subjective the human ear-brain interface is
>> that it can be fooled into thinking otherwise so easily.
>>
>>
>
> Well FM given a sufficient signal, and remember too that DAB needs a
> sufficient signal to work properly, can be very good indeed. And unlike
> DAB where that is degraded due to the "cost of bits" FM degrades to Mono
> only because of the signal level.
>

I prefer a GOOD digital implementation, mostly because the common
problems with FM are because the signal is NOT good.

Unless you lose frames completely, the response of a decent digital
system in noise is better.

So a hissy FM signal becomes a perfectly clean digital signal.

Also, the problems of audio distortion only start after what is in
decent signal conditions a 'perfect' decoder. Misaligned IF strips wont
affect the sound quality at all as long as the decoder can decode, it
will decode 'perfectly'


> I've had a FM versus CD setup here using a first class NCO type
> modulator and only about one person could reliably tell the difference
> and that was on solo soprano voice!.

Odd that. I got the worst FM degradations when I played with it years
ago on complex upper register stuff..mainly due to phase shifts at high
modulation depthsh and pretty high frequencies..upset the stereo
decoding as well.

In the days when it was only the home service, the light program etc
etc. and guaranteed 400KHZ spacings a very broadband IF strip gave you
very decent performance: the necessity to pull that down to reject
adjacent channels in a more crowded spectrum bolloxed up the audio
performance. Add in cheap ceramic IF filters instead of tuneable cans,
and for most people, the performance wasn't that good. OK you COULD get
very expenisve tailored filters that were both fast cutoff and minimal
phase shift, but that was serious money..

I suppose what I am saying is, whilst in theory an FM signal is superior
to a bad DAB signal, the reality of MOST peoples experience is that
neither the signal strength, nor the quality of the receiving equipment
is good enough to make that a fact in practice.

With digits, the chipsets take all the hard work out of the quality: you
get a predictable performance at far lower production costs.

Frankly here, I get a better audio performance out of audio streaming
over the internet than I do for all but my most expensive tuner.

I mean fer chrissake I was getting RUSSIAN instead of radio 2.. on FM.
Leastways it sounded slavic. That was an FM portable..some sort of freak
atmospherics I suppose.