|
|
Wireless audio distribution?
CJT wrote: Pooh Bear wrote: Which is why you have a receive buffer and there's latency between transmission and reception. Graham 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 |
Wireless audio distribution?
Rich Grise wrote:
On Thu, 04 Aug 2005 03:00:51 +0100, Pooh Bear wrote: Rich Grise wrote: On Thu, 04 Aug 2005 01:07:23 +0100, Pooh Bear wrote: That's the raw data rate only ! Now you have to add overhead for the frequency hopping stuff, handshaking, whatever and redundancy for lost packets - and I've no idea how the data's encapsulated - there'll doubtless be extra stuff there too. I'm not calculating this myself, I have it on good authority from some guys who are developing the product. I was quite surprised how much overhead is required myself actually. You don't have to use TCP/IP, and you don't need, or even want, lost packet redundancy, at least not for streaming audio. If you need a protocol at all, use something like UUCP. 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. ;-) 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 :-p 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 |
Wireless audio distribution?
"CJT" wrote in message ... 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 |
Wireless audio distribution?
Arny Krueger wrote:
"Pooh Bear" wrote in message Arny Krueger wrote: "CJT" wrote in message 44.1 ksamples/sec * 16 bits/sample * 2 channels = 1,411,200 bits/sec In any case, it's 1.4 Mbits/sec, NOT 6 Mbits/sec. That's the raw data rate only ! Now you have to add overhead for the frequency hopping stuff, handshaking, whatever and redundancy for lost packets - and I've no idea how the data's encapsulated - there'll doubtless be extra stuff there too. I'm not calculating this myself, I have it on good authority from some guys who are developing the product. I was quite surprised how much overhead is required myself actually. 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. 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? 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/dellsto...c=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. 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. 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. The OP merely speculated about wireless links. 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. 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. 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. 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 |
Wireless audio distribution?
Tim Martin wrote: "CJT" wrote in message ... 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. 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 |
Wireless audio distribution?
|
Wireless audio distribution?
Pooh Bear wrote:
CJT wrote: Pooh Bear wrote: Which is why you have a receive buffer and there's latency between transmission and reception. Graham 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 Sounds to me like you've got a solution in search of a problem. -- The e-mail address in our reply-to line is reversed in an attempt to minimize spam. Our true address is of the form . |
Wireless audio distribution?
Pooh Bear wrote:
Arny Krueger wrote: "Pooh Bear" wrote in message Arny Krueger wrote: "CJT" wrote in message 44.1 ksamples/sec * 16 bits/sample * 2 channels = 1,411,200 bits/sec In any case, it's 1.4 Mbits/sec, NOT 6 Mbits/sec. That's the raw data rate only ! Now you have to add overhead for the frequency hopping stuff, handshaking, whatever and redundancy for lost packets - and I've no idea how the data's encapsulated - there'll doubtless be extra stuff there too. I'm not calculating this myself, I have it on good authority from some guys who are developing the product. I was quite surprised how much overhead is required myself actually. 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. 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? 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/dellsto...c=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. 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 ! Who wants to walk down the hall to insert a CD when it can be instantly available on a file server? 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. The OP merely speculated about wireless links. 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. 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. I certainly don't. That's why I use silent/fanless Sun Ray thin clients for a similar application. They can be had for under 50 bucks with careful shopping. 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. 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 -- The e-mail address in our reply-to line is reversed in an attempt to minimize spam. Our true address is of the form . |
Wireless audio distribution?
On Fri, 05 Aug 2005 01:23:19 GMT, CJT wrote:
[snip] Who wants to walk down the hall to insert a CD when it can be instantly available on a file server? [snip] Some of us have a 300 CD jukebox ;-) ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
| All times are GMT. The time now is 05:41 PM. |
Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.0.0
Copyright ©2004-2006 AudioBanter.co.uk