Volume control at the speaker?

[Arny Krueger]

Even accepting your numbers, a 10 Mbps link is adequate.
So it's not necessary to resort to MP3.

I was just listening to some .wav files stored on a file
server across the room, using a SMC 2662W USB-attached
plain-old-vanilla old-tech, low-tech 802.11b wireless
interface. The file I was listening to with Winamp was a
44/16 stereo .wav file.

There's also the slight matter of 802.11a which delivers an
uncompressed 54 mbps, over shorter distances but still
plenty fine to reach across a room or a house.

 

[Zak]

DaveC wrote:

Currently only at mp3 like quality. True16 bit linear pcm in stereo @ 44kHz
sampling requires something like about 6 Mbps of bandwidth.

Uhh... 44.1 KHz * 16 bits * 2 channels = 1.4112 Mbit / sec....
definitely possible.


Thomas

 

[Tim Martin]

Product Specifications
. Digital Audio File Formats:
- MP3 up to 320 Kbps or variable bit rate (VBR)
- WMA 8/9 to 192 Kbps
- Internet Radio (streaming MP3)

http://www.netgear.com/pdf_docs/MP101_ds_NA_30Nov04.pdf

..wav and lpcm support was added via a software update; they are not in the
manual

Tim

 

[Tim Martin]

So, if I was to point you to a company that's actually working on uncompressed
digital audio links and they confirmed what I said, would you apologise for your
stupid comment above ?

Wireless computer network links can and do work at ten million bits a second
or more, with nominal speeds several times that figure.

I've been monitoring my wireless network transmission to my Netgear MP101
while playing an 860MB .wav file (44100Hz/16-bitstereo), and it is sending
data at about 200,000 bytes a second, which is about what you'd expect for
an uncompressed file. The server software CPU consumption is near-zero -
less than 5 CPU seconds in the last 5 minutes.

Tim

 

[Tim Martin]

In a distributed audio system in a residence, how can volume control in

each > room be accomplished.

After all the discussion, I do recommend checking out prices to see how much
you'd have to pay for Netgear MP101s ... you should be able to get them for
$100 or less. If you already have a wireless network, and are not totally
strapped for cash, they're worth getting at that kind of price. (There are
similar devices, but I'm not familar with those.) The Netgear has a
headphone socket, so I guess you could install one in your bedroom for
listening to music from your PC or internet radio stations.

I think wireless networks area bit more fiddly to set up than the
manufacturers say. And you need to follow the guidelines for security.

And I think the user interface on all these network music players is
fiddly - they are typically limited to a four line display, operated via a
remote control. The best way to use them seems to be to set up playlists,
and have the network music players play those.

Netgear do also make the MP115 media player, which can play video and audio
files from your PC over a wireless network. It costs about twice as much as
the MP101. I've not seen one, but I'd hope the interface may be easier to
use, as it connects to a TV screen.

Tim

 

[Pooh Bear]

Uhh... 44.1 KHz * 16 bits * 2 channels = 1.4112 Mbit / sec....
definitely possible.

It's *possible* - just not currently commercially available. That's the raw data
rate btw. It'll take a lot more bandwidth to get it wirelessly from A to B.

Graham

 

[Pooh Bear]

I was just listening to some .wav files stored on a file
server across the room, using a SMC 2662W USB-attached
plain-old-vanilla old-tech, low-tech 802.11b wireless
interface. The file I was listening to with Winamp was a
44/16 stereo .wav file.

There's also the slight matter of 802.11a which delivers an
uncompressed 54 mbps, over shorter distances but still
plenty fine to reach across a room or a house.

That's from *computer to computer* over a wireless network.

I never said that couldn't be done. We were discussing a standalone link
that's suitable for replacing hard wiring, where you have 'dumb box' to
receive the wireless audio. I don't see having a PC in every room just
to receve audio as a practical solution.

If you have a computer at the far end you can indeed send your file over
wireless ethernet. It takes a fair bit of the bandwidth on a slower
connection though. Standalone systems are a different kettle of fish. I
know of *none* currently offering 16 bit linear pcm and I can assure you
I've researched it very thoroughly. It may seem surprising but it's a
fact. It is being worked on though. I can't say too much on account of
an NDA.

Graham

 

[Pooh Bear]

I don't care a whole lot about what *one* company is *working on*. How
about you point me to an *ANSI* Standard, or even one in progress in a
Working Group?

Oh..... I remember, you like to make reference to "standards" that aren't
really Standards.

IMHO you aren't trustworthy in discussions.

And you're a worthless plonker who can't even respond to a straight question. I'd
forgotten you're one of Gay Mason's mates. Explains a great deal.

Graham

 

[Pooh Bear]

The Turtle Beach Audiotron does .wav, and if you wanted to, you could
link to it via wireless.

It rather appears that it does the typical 'sub-band codec' thing with a wav file.

Part of the audio tech spec for the Audiotron is as follows - and it's not the spec to
be expected of linear 16 bit pcm.


Signal to Noise 91dB (A-weighted)

THD+N -78dB (A-weighted) (-78dB = .0125%)

http://www.turtlebeach.com/site/products/audiotron/specs.asp

I hope you understand why this clearly isn't linear 16 bit. I've never even seen a
manufacturer have the brass neck to A-weight a THD spec before ! Talk about being
desperate.

Graham

 

[Pooh Bear]

They are, but not as you might know, or want to pay for them)

I was indeed simply considering the consumer market ! ;-)

Graham

 

[Rich Grise]

If you don't account for lost packets what's going to happen to any lost audio data ? I'll
ask some more next time I talk to the guys about the protocol they're using.

You leave it gone, because if you try to resend it, you'll lose ensuing
packets, or at least they'll get out of order. You drop it, and keep
on truckin'...

And if it's just streaming bits, you won't lose whole packets, and a
bit or two here and there is insignificant for, say, MP3. ;-)

Cheers!
Rich

 

[Pooh Bear]

Wireless computer network links can and do work at ten million bits a second
or more, with nominal speeds several times that figure.

I've been monitoring my wireless network transmission to my Netgear MP101
while playing an 860MB .wav file (44100Hz/16-bitstereo), and it is sending
data at about 200,000 bytes a second, which is about what you'd expect for
an uncompressed file. The server software CPU consumption is near-zero -
less than 5 CPU seconds in the last 5 minutes.

Ok - that's a standard wireless computer network right ?

I'll bet that whatever utility measures the data rate is simply looking at the
raw data transferred - the actual traffic that the 'network' sees - not the RF
data rate in bps.

I wouldn't expect to see much CPU utilisation - I expect the ethernet
controllers do most of the hard work.

I was talking about a *standalone* point to point method of distributing audio
wirelessly. There's no ethernet controller to take the strain nor any OS, CPU or
whatever.

Incidentally, I decided it was time to do some more Googling since the company I
was expecting to deliver still hasn't come up with the goods.

You may find this interesting - it appears to be the first chipset designed for
this function. It's barely in production it seems. I was kinda guessing at the
6Mbps data rate. They've apparently managed to get it into 4Mbps. Still a lot
more than the raw 1.4Mbps of the raw audio data though.

http://www.nvlsi.no/index.cfm?obj=document&act=display&doc=242

" Nordic launches nRF24Z1 - an Industry First Single Chip 2.4GHz 4Mbit/s
Solution for CD-Quality Wireless Audio Streaming, with Extremely Low Latency "

Graham

 

[Arny Krueger]

That's from *computer to computer* over a wireless
network.

In this day and age, just about *everything* is a computer.

What's the difference between a $299 stand-alone dedicated
client and a $399 computer besides 33% higher cost?

http://configure.us.dell.com/dellstore/config.aspx?c=us&cs=19&l=en&oc=D30CL1&s=dhs

I never said that couldn't be done. We were discussing a
standalone link that's suitable for replacing hard
wiring, where you have 'dumb box' to receive the wireless
audio. I don't see having a PC in every room just to
receve audio as a practical solution.

I believe the OP said:

"Is there a wireless solution to distributing audio
throughout a residence to
8 rooms? Digital?"

One approach is to have a file server loaded with audio
files that are to be distributed. Clients at each location
download the audio that is desired at that location.

Another approach is to have intelligent clients that stream
audio from off-site services through an on-site router.

If you have a computer at the far end you can indeed send
your file over wireless ethernet. It takes a fair bit of
the bandwidth on a slower connection though.

I believe the OP said nothing about the wireless connection
being necessarily slow, given that the wireless connection
was generally available for a reasonable cost.

Standalone
systems are a different kettle of fish. I know of *none*
currently offering 16 bit linear pcm and I can assure you.

But a distributed solution running 16 bit linear PCM can be
assembled from inexpensive computers.

I've researched it very thoroughly. It may seem
surprising but it's a fact. It is being worked on though.
I can't say too much on account of an NDA.

OK, someone puts together a Linux box and some software.

 

[Pooh Bear]

Unless you buffer the whole session (e.g. a complete song, or perhaps
even a complete CD), there's always the possibility of a buffer not
arriving in time.

I think that's the point.

You could lose *any* given sample. The simplest method of dealing with that is to continually
broadcast the data twice. If the previous error rate was 1 in 10^-6 then that method ( assuming
random errors ) should reduce it to1 in 10^-12. Not *perfect* but pretty damn good !

Sending the data twice also removes the need for negotiation over missed samples between transmitter
and receiver. It sounds like a done deal to me.

That also explains the need for a much higher data rate than 1.4Mbps.

Graham

 

[Pooh Bear]

You leave it gone, because if you try to resend it, you'll lose ensuing
packets, or at least they'll get out of order. You drop it, and keep
on truckin'...

And if it's just streaming bits, you won't lose whole packets, and a
bit or two here and there is insignificant for, say, MP3. ;-)

My best guess is that the simplest way to deal with occasional lost packets is simply to send
the data twice and discard the erroneous data. Doing stuff in real time is rather different to
computer networking where it doesn't matter too much if the file's delayed a bit.

I hear you about mp3

My interest is actual proper 16 bit linear pcm. You'll definitely notice a lost packet with that
! I don't think that clicks will be very acceptable. ;-)

Graham

 

[Tim Martin]

The Turtle Beach Audiotron does .wav, and if you wanted to, you could
link to it via wireless.

Yes, and I think the Squeezebox does too. There are several of these
devices commercially available.

The $75 Linksys WMLS11B comes with little speakers and has audio and digital
out; I don't know if it can handle .wav files.

The $100 Netgear MP101 has built-in wired and wireless ethernet and handles
..wav (with downloadable firmware update), but does not have digital out

The $150 Philips Media Playerhas built-in wireless ethernet and handles
video. (This seems similar to the Prismiq Mediaplayer)

The $160 Creative Sound Blaster Wireless has digital out, but doesn't seem
to handle .wav files

The $200 Audiotron does not have built-in wireless (obviously you can
install a wireless internet link and connect the Audiotron to that.) but it
does handle .wav and has digital output.

The $200 Omnifi DMS1W does not have digital output, but can connect to a TV
for its user interface. I don't know if it supports .wav

The $300 Squeezebox is from Slim Devices, the company who (I believe) were
first to market.

The Philips Streamium comes with speakers and CD player (which will play MP3
CDs, too) and has wireless ethernet.

I expect he's talking about devices which can be used as a simple audio
cable substitutes, rather than devices which work with a computer server. I
guess to compete with the $100 Netgear, which has remote control of the
music being played, an audio cable replacement would have to cost $50 for
transmitter and receiver, and say $30 for each additional receiving station.

Tim

 

[Pooh Bear]

In this day and age, just about *everything* is a computer.

What's the difference between a $299 stand-alone dedicated
client and a $399 computer besides 33% higher cost?

A practical wireless audio distribution solution should really cost not much more than
a couple of hundred bucks total. That's an assessment I've made myself about a product
being realistically priced on the market. It'll drop with time of course but early
adopters will pay a bit more for leading edge technology.

And the OP *doesn't need* or *want* a computer simply to hear music ! - never mind the
fact that they crash all the time and add acoustic noise ! You need a simple
standalone solution that you plug in and it works. Not a definition of a PC by any
means !

Remember - the alternative is a piece of screened wire !

http://configure.us.dell.com/dellstore/config.aspx?c=us&cs=19&l=en&oc=D30CL1&s=dhs


I believe the OP said:

"Is there a wireless solution to distributing audio
throughout a residence to
8 rooms? Digital?"

One approach is to have a file server loaded with audio
files that are to be distributed. Clients at each location
download the audio that is desired at that location.

Who said he was using a *FILE SERVER* ? What about simply putting a CD into the CD
player. Most ppl still do this you know !

Another approach is to have intelligent clients that stream
audio from off-site services through an on-site router.


I believe the OP said nothing about the wireless connection
being necessarily slow, given that the wireless connection
was generally available for a reasonable cost.

The OP merely speculated about wireless links.

But a distributed solution running 16 bit linear PCM can be
assembled from inexpensive computers.

How may ppl actually *want* their homes polluted with computers to do simple tasks ?
They are big, ugly, unreliable, noisy, quite expensive even now and use lots of power.

OK, someone puts together a Linux box and some software.

Someone has finally got their act together it seems.

http://www.wirelessnetdesignline.com/products/57700997

Oslo, Norway— Nordic Semiconductor introduces the nRF24Z1, a complete digital wireless
audio streamer solution in a 6x6mm package. The device uses the company's 4Mbit/s
MegaZtream platform with an embedded Quality of Service (QoS) subsystem, a low power,
robust 4Mbit/s wireless 2.4GHz transceiver, and all appropriate digital audio
interfaces.

Designed for wireless audio streaming applications, the nRF24Z1 is optimized to
operate in the presence of potentially disturbing sources such as WLAN, cordless
telephones, and Bluetooth. The RF transceiver portion is designed to ensure that there
is bandwidth enough to stream and transmit 16-bit 48Kspls/s CD quality audio without
using compression. In addition to streaming audio, the nRF24Z1 also features a digital
control information channel for transfer of control information such as volume,
balance, track and display information.

Some key audio features include: I2S serial connection for glue less interface to
virtually all audio chipsets as well as low cost A/D and D/A for analog audio, S/PDIF
interface for direct digital connection to PC and surround receivers, input supports
audio up to 24 bit 96Kspl/s directly, output supports audio up to 16 bit 48kspl/s
directly, and programmable low 2-18ms link latency

Suited for use in portable as well as stationary equipment, the chipset is specified
with 5mA average current (streaming MP3 data @ 192Kbit/s) and 15mA average current
(streaming LPCM data @ 1.5Mbit/s). The nRF24Z1 is sampling. Volume production is
scheduled for April 2005. The nRF24Z1(TM) is priced at USD $4.00 in 10K quantities


Graham

 

[Pooh Bear]

Yes, and I think the Squeezebox does too. There are several of these
devices commercially available.

The $75 Linksys WMLS11B comes with little speakers and has audio and digital
out; I don't know if it can handle .wav files.

The $100 Netgear MP101 has built-in wired and wireless ethernet and handles
.wav (with downloadable firmware update), but does not have digital out

The $150 Philips Media Playerhas built-in wireless ethernet and handles
video. (This seems similar to the Prismiq Mediaplayer)

The $160 Creative Sound Blaster Wireless has digital out, but doesn't seem
to handle .wav files

The $200 Audiotron does not have built-in wireless (obviously you can
install a wireless internet link and connect the Audiotron to that.) but it
does handle .wav and has digital output.

The $200 Omnifi DMS1W does not have digital output, but can connect to a TV
for its user interface. I don't know if it supports .wav

The $300 Squeezebox is from Slim Devices, the company who (I believe) were
first to market.

The Philips Streamium comes with speakers and CD player (which will play MP3
CDs, too) and has wireless ethernet.

I expect he's talking about devices which can be used as a simple audio
cable substitutes, rather than devices which work with a computer server.

Correct ! That's what the OP wanted. A *simple* standalone method of 'piping'
audio to many rooms in a house.

I
guess to compete with the $100 Netgear, which has remote control of the
music being played, an audio cable replacement would have to cost $50 for
transmitter and receiver, and say $30 for each additional receiving station.

It would indeed want to be quite low cost or the attraction vanishes. I'd
venture that a higher price would be acceptable initially before it became
mass-market - although that may happen quite quickly now it seems.

Graham

 

[Don Bowey]

And you're a worthless plonker who can't even respond to a straight question.
I'd
forgotten you're one of Gay Mason's mates. Explains a great deal.

I believe I answered your question.

Now you are doing your other well known thing of tossing in crap to
misdirect the topic.

Guy Mason has nothing to do with my points of view. You are an ass for your
comment.

You have no integrity.

 

[CJT]

It rather appears that it does the typical 'sub-band codec' thing with a wav file.

My server feeds one raw .wav files. It just works.

Part of the audio tech spec for the Audiotron is as follows - and it's not the spec to
be expected of linear 16 bit pcm.


Signal to Noise 91dB (A-weighted)

You know these things have an analog stage, too, right?