Current trends in audio
 

In article , Eiron
wrote:
A potential problem here would be that speakers, in general, don't
stop radiating the instant you abruptly cut off input to them. So when
you switched, one would still be 'ringing down' in its own way as the
other speaker 'gets going'.

Unless you have a one-note hi-Q subwoofer this isn't a problem.

Do you know this from trying it? I'm not just thinking about the bass
resonance, but also about effects like cabinet vibrations. Also the
below...

I'd have suspected that even if I tried this switching from one QUAD ESL
pair to another I'd notice the change in imaging. Possibly also the change
in sound due to the different speaker locations in the room. But I've never
tried anything like this with speakers.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

MP3 coding (was Current trends in audio)
 

Jim Lesurf said:
In article ,
Richard Robinson wrote:

Still, I am surprised that mp3s don't have metadata to enable a
successful rebuild to the original.

Could that be done, without storing the original data ?
[...]
Either way, the info has to be somewhere, and accessible to you.

For music, LPCM tends to be wasteful. So you can reshuffle how it is
represented and that tends to reduce the number of bits required. Flac
works pretty well for this. Although that has the snag that genuine random
background noise is preserved just as if it were 'real' information. This
is the main reason many 'High Rez' flac files are so big. Noise, carefully
preserved in every detail, not actually shedloads of more *musical* info.

Yes. That's not the code's problem, though, is it ? If you don't want to
throw anything away you get to keep what's there. Noise in noise out, to
paraphrase.


--
Richard Robinson
"The whole plan hinged upon the natural curiosity of potatoes" - S. Lem

My email address is at http://www.qualmograph.org.uk/contact.html

Current trends in audio
 

On 23/01/2017 14:00, Dave Plowman (News) wrote:
In article ,
Graeme Wall wrote:
Not quite sure what you mean. The OnDigital system effectively morphed
into FreeView.

When the BBC got involved.

Quite. The original On Digital setup was a consortium of Thatcher's
favourite ITV companies whose only motive was to make a lot of money. But
sadly hadn't a hope when up against the likes of the dirty digger.


I had OnDigital from the start, and didn't have problems with picture
break up. But like all digital systems it reacts differently to a poor
signal than analogue.


AIUI the initial OnDigital service was not marketed to home subscribers,
but I could be wrong!

Think it always was - the idea being they could charge a subscription for
it. As well as things like footie for pubs. Rather like Sky is now. I only
wanted it for HD, though.

That may have been the problem, the sports feeds were initially all SD.


There were problems initially with low field strengths which continued
until analogue was switched off. Not a problem here - I can see the CP
mast from the rear of the house.


If I stood on the roof, next to my aerial, I could see Rowridge and
Chillerton :-)

--
Graeme Wall
This account not read.

Current trends in audio
 

On 23-01-17 14:33, Phil Allison wrote:

** You gotta be ****ing kidding us !!!!!!!!!!
Pay $33 to read complete tripe ???

Ah, so you are not an Audio Engineering Society member then?

**** YOU !!!

I would suggest you might want to check your medication.

FYI:

I have tolerated this pig ignorant, Dutch MP3 fascist far too long.
From now on, no more Mr Nice Guy.
Hey Joahan, get your hands off it.
This NG is about home Hi-Fi and you have no ****ing clue what that even is.
You have no idea what anyone thinks - except you.
Cos you are a boorish, autistic moron.
Just like all Dutch pigs.

FYI, you don't seem to be able to spell my name correctly, not
that it really matters. And feel free to call me ignorant, fascist,
boorish, autistic, moron or even a pig. Just don't call me Dutch.

Julf

Current trends in audio
 

"Phil Allison" wrote in message
...
Johan Helsingius wrote:

Phil Allison wrote:

** Yes, and the result shows how useless all A then B tests are
and by implication variations like ABX.


You seem to keep assuming that ABX tests don't allow for instantaneous
back-and-forth switching,


** According the Arny Kruegar who built the relay boxes - they never did
in practice.


but even the original ABX Company paper
(by David Clark) from 1982 talks about their device being equipped
with user-controllable switchover pushbuttons (and discusses ways
to avoid the relay switchover being audible).

http://www.aes.org/e-lib/browse.cfm?elib=3839


** You gotta be ****ing kidding us !!!!!!!!!!

Pay $33 to read complete tripe ???

**** YOU !!!

FYI:

I have tolerated this pig ignorant, Dutch MP3 fascist far too long.

From now on, no more Mr Nice Guy.

Hey Joahan, get your hands off it.

This NG is about home Hi-Fi and you have no ****ing clue what that even
is.

You have no idea what anyone thinks - except you.

Cos you are a boorish, autistic moron.

Just like all Dutch pigs.



(Ahem!). Actually Phil, Johan is a Swedish-speaking Finn.
They are in general some of the nicest and most cultured
people it will ever be your priviledge to meet.

Iain

Current trends in audio
 

In article ,
Graeme Wall wrote:
Think it always was - the idea being they could charge a subscription
for it. As well as things like footie for pubs. Rather like Sky is
now. I only wanted it for HD, though.

That may have been the problem, the sports feeds were initially all SD.

Of course. TV cameras are extremely expensive devices and only really
replaced when their time comes. Same with all the peripheral gear. If you
remember how long it took for everything to go colour too.

--
*How can I miss you if you won't go away?

Dave Plowman London SW
To e-mail, change noise into sound.

MP3 coding (was Current trends in audio)
 

"Jim Lesurf" wrote in message
...
In article ,
Richard
Robinson wrote:

Still, I am surprised that mp3s don't have metadata to enable a
successful rebuild to the original.

Could that be done, without storing the original data ?

The 'physical' measure/unit of the quantity of information is 'bits'. It
follows from the basics of Information Theory that a given 'message' will
contain some amount of information. You can transform or shuffle this to
try and remove waste, but then end up with the result not being any
smaller
if you don't want to lose any information.

Attempts to do otherwise either:

1) Throw away some info and hope you won't notice.

and/or

2) Cheat. :-) By storing the info somewhere else and using what you get as
the message an instruction to use that. Magic of Indirection. :-)

Either way, the info has to be somewhere, and accessible to you.

For music, LPCM tends to be wasteful. So you can reshuffle how it is
represented and that tends to reduce the number of bits required. Flac
works pretty well for this. Although that has the snag that genuine random
background noise is preserved just as if it were 'real' information. This
is the main reason many 'High Rez' flac files are so big. Noise, carefully
preserved in every detail, not actually shedloads of more *musical* info.

MP3 (and other lossy systems) tend to throw away info in the hope you
won't
care or notice. You can do this to *some* extent if done with due care and
not affect the result noticably. But inevitably, someone then wants to
wind
up the compression to '11'... 8-

When saviong audio in .mp3 most DAWS ask "You are saving to a
compressed/lossy format. Are you sure? This implies there is no
going back once you press Enter.

Iain

Current trends in audio
 

On 23/01/2017 15:51, Dave Plowman (News) wrote:
In article ,
Graeme Wall wrote:
Think it always was - the idea being they could charge a subscription
for it. As well as things like footie for pubs. Rather like Sky is
now. I only wanted it for HD, though.

That may have been the problem, the sports feeds were initially all SD.

Of course. TV cameras are extremely expensive devices and only really
replaced when their time comes. Same with all the peripheral gear. If you
remember how long it took for everything to go colour too.


I came in near the end of that fortunately. Though I remember doing
programmes (Playschool and Jackanory) in colour studios with the colour
burst switched off because they only had budgets for B&W!

--
Graeme Wall
This account not read.

Current trends in audio
 

On 23-01-17 16:31, Iain Churches wrote:

(Ahem!). Actually Phil, Johan is a Swedish-speaking Finn.
They are in general some of the nicest and most cultured
people it will ever be your priviledge to meet.

As long as you can stand herring, vodka schnapps and
drinking songs... :)

Julf

MP3 coding (was Current trends in audio)
 

Jim Lesurf said:
In article ,
Richard
Robinson wrote:

That's a thing that hadn't occured to me. Is it a similiar algorithm ?
It would be an easier & less time-consuming test.

At a the simplest mathematical level, yes. MP3 and JPEG use the same basis.

Each uses a Fourier Transform to generate a series of 'spectra'. These then
have the values which the encoder examines and decides which ones you won't
mind being left out when the results are stored. (Some results are stored,
but possibly with lower resolution which means they take fewer bits.)

The differences are that MP3 does a 1D temporal spectrum per chunk/channel
whereas JPEG uses 2D spatial ones. But from an basic IT POV that's a mere
detail.

Yes, I can (vaguely) see that. Thanks.

They key here is actually not just the output bitrate but what are called
"judgement rules". These are some instructions given to the encoders to tel
them how to decide what to omit when encoding, and what to keep, but with
some level or reduction in resolution. Optimising these gets the best
trade-off between the size of the result and its quality. But you can't get
owt for nowt, hence comments I've made in another posting. :-)

Yes, that seems like the vital point about 'lossy', how you decide what won't be
missed (and then recognise it in the data).



--
Richard Robinson
"The whole plan hinged upon the natural curiosity of potatoes" - S. Lem

My email address is at http://www.qualmograph.org.uk/contact.html