Wireless transmitter
 

In article , Arny Krueger
scribeth thus

"Rob" wrote in message
web.com...
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

In the world of professional audio, wireless connections are considered to
be substandard unless they implement a true diversity reception system.
This means two independent receiving antennas, two independent receivers,
and a detection and logic system that picks the best received signal at all
times. Some of the best systems base the SQ evaluation on an ultrasonic
subcarrier.

Also, the whole system if based on analog (e.g. FM) is surrounded by
companding which can elevate effective dynamic range from about 60 dB to
more like 100 dB.

Finally, there should be some kind of frequency mobility so that
interference sources can be completely avoided.

Well there is but in that part of the spectrum over here 2.4 Ghz, there
are a lot of devices using that now which the limiting factor!..

We had a digital link once that used 2.4 G over some miles but after
some time that started cutting out simply due to interferer's...

Full AES/EBU digital it was too..

What you're showing me seems to be a toy, not a professional tool. How these
comments impact you depends on your goals for performance.



--
Tony Sayer

Wireless transmitter
 

"Arny Krueger"
"Rob"
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

In the world of professional audio, wireless connections are considered to
be substandard unless they implement a true diversity reception system.
This means two independent receiving antennas, two independent receivers,
and a detection and logic system that picks the best received signal at
all times. Some of the best systems base the SQ evaluation on an
ultrasonic subcarrier.

Also, the whole system if based on analog (e.g. FM) is surrounded by
companding which can elevate effective dynamic range from about 60 dB to
more like 100 dB.


** OTOH - modern digital communication is almost wholly of the " spread
spectrum " kind and has few if any of the issues that have long plagued
analogue FM systems used by the vast majority of radio mics.


Finally, there should be some kind of frequency mobility so that
interference sources can be completely avoided.

** Frequency hopping does away with that need.

A single spread spectrum device uses as much bandwidth as the tuneable
frequency range typical, low powered FM audio transmitter.

What you're showing me seems to be a toy, not a professional tool.

** Agreed, but not for the spurious reasons you mention.



..... Phil

Wireless transmitter
 

On 05/05/2012 10:28, Dave Plowman (News) wrote:
In aweb.com,
wrote:
On 04/05/2012 23:45, Dave Plowman (News) wrote:
In raweb.com,
wrote:
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

Have you read the reviews at the bottom of the page?


Yes - they seem to mention reliability. Any comments on the concept in
terms of audio? Or is the concept intrinsically unreliable?

Radio links can of course work perfectly well under good conditions. But
many of these sort of things don't work well in practice. Other devices
interfering with the signal or that signal not being powerful enough to go
through walls etc.

All you can really do is try it and see if it works, as so much depends on
local conditions. And hope Maplin will refund if it doesn't suit.


It could be a convenient method (for me) of attaching the proper stereo
to the TV system. I'd thought perhaps the technology had actually
'locked down' into something that worked - apparently not then, just yet.

Rob

Wireless transmitter
 

On 05/05/2012 10:52, tony sayer wrote:
In aweb.com, Rob
scribeth thus
On 04/05/2012 23:45, Dave Plowman (News) wrote:
In raweb.com,
wrote:
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

Have you read the reviews at the bottom of the page?


Yes - they seem to mention reliability. Any comments on the concept in
terms of audio? Or is the concept intrinsically unreliable?

Rob

It I suspect works on 2.4 Ghz which is now becoming very crowded with
the explosion in wi-fi. I 'd expect it to work well in the absence of
any interfering signals, but these places are now very few and far
between..

A lot of wireless problems are simply caused by congestion of the
available spectrum allocated to it.

Also signal attenuation is quite high in some domestic environments

It may well work fine today but tomorrow when next door start using
their new wi-fi point all the time and perhaps the one across the
way?....


Ah right, seems like a bother.

Use wire if you can, a lot more reliable;)..

Indeed, know where you are!

Rob

Wireless transmitter
 

On 05/05/2012 09:42, Jim Lesurf wrote:
In aweb.com, Rob
wrote:
On 04/05/2012 23:45, Dave Plowman (News) wrote:
In raweb.com,
wrote:
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

Have you read the reviews at the bottom of the page?


Yes - they seem to mention reliability. Any comments on the concept in
terms of audio? Or is the concept intrinsically unreliable?

From the 'reviews' it looks like the specific device is prone to cross
interference because it uses the same band as other equipment, and falls
over if you expect to get the signal though a wall.

Impossible to say much about sound quality since there seems to be no
detail at all on modulation methods, and lossy data compression, etc. Nor
any relevant test results or serious listening.

"Intrinsically" a radio link can work fine. But you would not be buying an
"intrinsic" concept. You'd be buying an implimentation that might be great
or might be rubbish.


Quite - I'd hardly list and quantify the variables that affect me, and
therefore define the parameters of implementation. It'd take a while,
but thanks for pointing it out.

Personally, I'm quite happy to use cables. They work nicely.


Goodo. Strikes me this sort of technology has a place for multi-source
and speaker setups, though.

Rob

Wireless transmitter
 

On 06/05/2012 12:52, Arny Krueger wrote:
wrote in message
eb.com...
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

In the world of professional audio, wireless connections are considered to
be substandard unless they implement a true diversity reception system.
This means two independent receiving antennas, two independent receivers,
and a detection and logic system that picks the best received signal at all
times. Some of the best systems base the SQ evaluation on an ultrasonic
subcarrier.

Also, the whole system if based on analog (e.g. FM) is surrounded by
companding which can elevate effective dynamic range from about 60 dB to
more like 100 dB.

Finally, there should be some kind of frequency mobility so that
interference sources can be completely avoided.

What you're showing me seems to be a toy, not a professional tool. How these
comments impact you depends on your goals for performance.


I'd be looking for 'as good as wire'.

Rob

Wireless transmitter
 

In article om, Rob
wrote:

It could be a convenient method (for me) of attaching the proper stereo
to the TV system. I'd thought perhaps the technology had actually
'locked down' into something that worked - apparently not then, just yet.

The problem isn't simply a matter of 'technology' as such. It is the
situation:

The problem is that the band/channel being used is also already widely used
for various purposes in a way that includes no 'plan' of who can transmit
how much power from which places. So cross interference becomes a certainty
as the density of users rises. That then at least will degrade the
reliability for any individual user, and either cause pauses or dropouts,
or lower bandwidth to an unacceptable level.

In general, 'broadcasting' and general radio transmission is controlled in
ways designs to avoid cross interference. If someone wants to transmit,
they have to get permission which depends on an assessment of the impact on
other services. But here you end up with 'crowded party' problems - unless
you live well clear of 'competing' users.

FWIW for indoor 'line of sight' you might be better looking to some kind of
near-visible 'optical' system where the transmitter lights up the room in a
modulated way. At least that helps prevent interference from next door. But
of course that won't go though walls, and may be affected by shadowing. I
can't suggest any commercial system, though. Personally, I'm quite happy in
general to use 'wired' systems at home unless there is a specific need to
do otherwise.

Slainte,

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

Wireless transmitter
 

In article om,
Rob wrote:
I'd be looking for 'as good as wire'.

Well, all the mains sockets and lights in your house will have wires going
to them. So the option is to do the same with everything else. Of course
it depends on the design of your house as to how easy this is to do.

--
*Vegetarians taste great*

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

Wireless transmitter
 

On 07/05/2012 10:42, Dave Plowman (News) wrote:
In raweb.com,
wrote:
I'd be looking for 'as good as wire'.

Well, all the mains sockets and lights in your house will have wires going
to them.

They will, yes.

So the option is to do the same with everything else.

Agreed.

Of course it depends on the design of your house as to how easy this is to do.

Yes, got that.

It'd be nice to have a wireless audio sender/receiver but by no means
necessary.

Rob

Wireless transmitter
 

In article m,
Rob wrote:
It'd be nice to have a wireless audio sender/receiver but by no means
necessary.

Well, try it and see. You may be lucky.

--
*Make it idiot-proof and someone will make a better idiot.

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