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Wireless Audio That Works!

post #1 of 20
3/13/13 at 4:51pm
Thread Starter 

Jim Venable, president of the Wireless Speaker and Audio (WiSA) Association, and Alan Ruberg, chief technologist of WiSA, talk about the next generation of wireless audio, with up to eight channels of 24-bit/96 kHz uncompressed digital-audio information transmitted in a relatively low-traffic radio-frequency region. They discuss important issues such as latency, interference, error correction, and certification as well as answers to chat-room questions and more.

 

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post #2 of 20
3/13/13 at 11:38pm
Great vid, I learned a lot. The tech sounds great.
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post #3 of 20
3/14/13 at 6:29am
This is interesting... But my take on it was: I believe it still wouldn't go through walls, which is something I would require, if I would ever upgrade to this type of tech. Lets say your source was the computer in another room--- 60ft away with walls.
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post #4 of 20
3/14/13 at 11:07am
I was recently asked to find a wireless speaker for a 60-foot transmission through a couple of interior walls. The client was my own mother, so I wanted to get it right. I did some searching and there were a ton of Bluetooth options, far fewer wireless speakers that had the range needed. The ones that did were inevitably 900Mhz or 2.1Ghz wireless speakers designed for outdoor use. An affordable, standards-based system that works well and carries the fidelity expected from indoor speakers would be just the ticket.
Edited by imagic - 3/14/13 at 1:21pm
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post #5 of 20
3/14/13 at 5:15pm
I've been starting to research possibilities for upgrading the sound system in a large motorhome I just purchased. Of course running speaker wires through motorhomes is usually a major problem so this technology sounds to be ideal. I will be watching for WISA products in the coming months.
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post #6 of 20
3/17/13 at 7:45pm
Interesting clip. I'm curious- during that 5 second buffering where it find another open bandwidth to use in case the current one become used, does it try to set it a decent ways apart from the current one? Basically, so if whatever competing signal has a wide bandwidth, will whatever it switches to be far enough away from it to basically ensure the new one is not within the same bandwidth?

Otherwise, interesting technology
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post #7 of 20
3/18/13 at 2:12am
Good stuff. Hope it works out. Love my wireless 5.1 in my bedroom except it interferes with the WiFi internet
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post #8 of 20
3/18/13 at 2:24pm
Quote:
Originally Posted by CMonMan View Post

Interesting clip. I'm curious- during that 5 second buffering where it find another open bandwidth to use in case the current one become used, does it try to set it a decent ways apart from the current one? Basically, so if whatever competing signal has a wide bandwidth, will whatever it switches to be far enough away from it to basically ensure the new one is not within the same bandwidth?

Otherwise, interesting technology

1) 5second--- I think it was 5mili... or 5nano? cant rem. If it was 5secs. It would be unusable. The tech is supposed to be up to gaming standards.
2) This was my take: In the video clip, they made i sound like, that most of the channel switching was govt mandated. Because it has to scan for radar. It seemed it wouldn't actually affect the wisa audio, only that it was doing it to stay off of bands that the govt was using. --- Like in the movie ET, when the govt was scanning the neighborhood...LOL
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post #9 of 20
3/18/13 at 2:39pm
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Originally Posted by robertkjr3d View Post

1) 5second--- I think it was 5mili... or 5nano? cant rem. If it was 5secs. It would be unusable. The tech is supposed to be up to gaming standards.
2) This was my take: In the video clip, they made i sound like, that most of the channel switching was govt mandated. Because it has to scan for radar. It seemed it wouldn't actually affect the wisa audio, only that it was doing it to stay off of bands that the govt was using. --- Like in the movie ET, when the govt was scanning the neighborhood...LOL

I get that, but what I'm saying is that in case the if the band that the government was using was a relatively large bandwidth, would the "new" channel be far enough away as to not be included in it as well?
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post #10 of 20
3/18/13 at 3:38pm
"This is interesting... But my take on it was: I believe it still wouldn't go through walls, which is something I would require, if I would ever upgrade to this type of tech. Lets say your source was the computer in another room--- 60ft away with walls."

I have been working with the WiSA Association for about a year and am somewhat familiar with the technology. The current WiSA specification for compliance says the wireless link between the hub and each the speakers has to work at least 30 feet when using 96kHz sampling rate, and 20 feet at 48kHz. Those are minimum line of sight. distances for compliance, the manufacturers are welcome to amplify the signal to reach well beyond that distance. 30 feet covers most living rooms, 60 feet covers most houses. Walls do matter, see other response.
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post #11 of 20
3/18/13 at 3:51pm
Quote:
Originally Posted by imagic View Post

I was recently asked to find a wireless speaker for a 60-foot transmission through a couple of interior walls. The client was my own mother, so I wanted to get it right. I did some searching and there were a ton of Bluetooth options, far fewer wireless speakers that had the range needed. The ones that did were inevitably 900Mhz or 2.1Ghz wireless speakers designed for outdoor use. An affordable, standards-based system that works well and carries the fidelity expected from indoor speakers would be just the ticket.

I agree. The quality is finally "there". Uncompressed, 24-bit, up to 96 kHz sampling rate. Moreover, WiSA certified speakers utilize the unlicensed 5.2-5.8 GHz band, also called the DFS channels. To be frank, this frequency band doesn't transmit through walls that well, but that is a good thing for home theater, as it gives natural separation from your neighbors. The WiSA Association sees the biggest need for wireless speakers in the living room, where flat panel TVs = thin sound. Many consumers would buy a surround sound system but don't want to install the wires. The current spec says the link between audio hub and speaker has to work 30 feet line of sight at 96khZ, but the signal can be easily amplified by the manufacturers to go further, and through walls. Multi-room audio presents other challenges the WiSA Association members are hoping to address in the near future.
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post #12 of 20
3/18/13 at 4:01pm
Quote:
Originally Posted by CMonMan View Post

Interesting clip. I'm curious- during that 5 second buffering where it find another open bandwidth to use in case the current one become used, does it try to set it a decent ways apart from the current one? Basically, so if whatever competing signal has a wide bandwidth, will whatever it switches to be far enough away from it to basically ensure the new one is not within the same bandwidth?

Otherwise, interesting technology
Quote:
Originally Posted by robertkjr3d View Post

1) 5second--- I think it was 5mili... or 5nano? cant rem. If it was 5secs. It would be unusable. The tech is supposed to be up to gaming standards.
2) This was my take: In the video clip, they made i sound like, that most of the channel switching was govt mandated. Because it has to scan for radar. It seemed it wouldn't actually affect the wisa audio, only that it was doing it to stay off of bands that the govt was using. --- Like in the movie ET, when the govt was scanning the neighborhood...LOL

It's 5ms delay. We find that many televisions take twice as long to process the HDMI signal. I have played SSX using WiSA demonstration surround sound systems at CES and ISE and can tell you it was instantaneous.

As for the frequency hop, I am not able to give the full algorithm, but should be able to clarify. Its somewhat government mandated, for instance, when a interference is detected on a channel you have to stay off it for a certain amount of time, I think its like one minute. There is also a look ahead requirement so you know if a channel is clear for a certain time before you jump to it. The system learns what channels were bad and avoids them. The system always has a clean backup channel ready to jump to in case of interference, and all the speakers jump at the same time, without missing a beat. The user does not know it jumped.
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post #13 of 20
3/18/13 at 4:44pm
Quote:
Originally Posted by PKaudiovisual View Post


It's 5ms delay. We find that many televisions take twice as long to process the HDMI signal. I have played SSX using WiSA demonstration surround sound systems at CES and ISE and can tell you it was instantaneous.

As for the frequency hop, I am not able to give the full algorithm, but should be able to clarify. Its somewhat government mandated, for instance, when a interference is detected on a channel you have to stay off it for a certain amount of time, I think its like one minute. There is also a look ahead requirement so you know if a channel is clear for a certain time before you jump to it. The system learns what channels were bad and avoids them. The system always has a clean backup channel ready to jump to in case of interference, and all the speakers jump at the same time, without missing a beat. The user does not know it jumped.

I meant 5ms, regardless- not exactly what I'm trying to ask. I guess what I'm saying is that how far apart is the next clear channel? Is it far enough away from the current channel being used so that if an interference is detected, and said interference has a relatively wide range, is the new channel far enough apart so that it isn't an issue? I'm not an expert by any means in this tech, so am having a hard time asking what I'm trying to say.
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post #14 of 20
3/19/13 at 2:11am
Sonos works unbelievably well through walls. I installed a Sonos in my folks place, which is very large, with no problems. I think WiSA is similar in tech, but SonosNet may be a variant of zigbee (mesh network).
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post #15 of 20
3/19/13 at 11:06pm
Fascinating video, thanks for posting!
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post #16 of 20
3/21/13 at 3:28pm
New on this board, hope I can add to the discussion. Unfortunately I do not have a very useful Internet connection and I pay by amount, so it costs me 10 bucks for every gigabyte of data I consume, which makes it painful to watch a short video, let alone an hours worth. Not to mention you have to wait ever 8 seconds for a few seconds for the video to start again.

Under the circumstances I was hoping that someone would relay some of the information from the video to me, such as frequency and from what I can pick up how fast is it frequency hopping? I'm always amused at the terms like "relatively low traffic" spectrum, ha ha... Not to mention the comments of 'skipping to miss government', well the government usually transmits in the gigawatt range where consumers are always in the micro watt range, even with line of sight transmissions. To add to our dismay they usually give the public areas that nobody wants or what's considered useless. They've been doing it to Amateur Radio operators for decades!

Anyway I'm interested and when I get to Phoenix next week I'll check out the video, I hope. Do they give you any details of how it works? I assume it's FM? or is it PM (phase modulated)? Do they even mention how it's modulated?

If they did the same for this as they did for WiFi in computers, then I'll have to check it out closer. In computers the wifi channels overlap and you have to have 6 channels of separation to ensure good performance. It would be refreshing to have something that actually works well instead of a compromise between the people interested in the frequency and spectrum width.

Any information would be nice if anyone remembers...

Thanks,

Jack
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post #17 of 20
3/22/13 at 12:12pm
Quote:
Originally Posted by CMonMan View Post

I meant 5ms, regardless- not exactly what I'm trying to ask. I guess what I'm saying is that how far apart is the next clear channel? Is it far enough away from the current channel being used so that if an interference is detected, and said interference has a relatively wide range, is the new channel far enough apart so that it isn't an issue? I'm not an expert by any means in this tech, so am having a hard time asking what I'm trying to say.

I think I understand what you are asking, if it detects interference, how far away (in Hertz) does it jump to ensure it won't hit the same interference? The number of available (legal to use) DFS channels between 5.2 and 5.8 GHz varies per region, but one can expect roughly 14 DFS available channels in a given country. The WiSA technology follows the rules of DFS in that it constantly scans all of the DFS channels to see which are open and which are not. A channel has to be open and interference free for a minute before the system jumps to it, by law. The jump could be to an adjacent channel or the other end of the spectrum, depending on what channels are being used. The system learns what channels are really bad and avoids jumping back to them.

if you want to delve further, send an email to info@wisaassociation.org and we will put you directly in touch with Alan.
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post #18 of 20
3/22/13 at 12:24pm
Quote:
Originally Posted by jkwilborn View Post

New on this board, hope I can add to the discussion. Unfortunately I do not have a very useful Internet connection and I pay by amount, so it costs me 10 bucks for every gigabyte of data I consume, which makes it painful to watch a short video, let alone an hours worth. Not to mention you have to wait ever 8 seconds for a few seconds for the video to start again.

Under the circumstances I was hoping that someone would relay some of the information from the video to me, such as frequency and from what I can pick up how fast is it frequency hopping? I'm always amused at the terms like "relatively low traffic" spectrum, ha ha... Not to mention the comments of 'skipping to miss government', well the government usually transmits in the gigawatt range where consumers are always in the micro watt range, even with line of sight transmissions. To add to our dismay they usually give the public areas that nobody wants or what's considered useless. They've been doing it to Amateur Radio operators for decades!

Anyway I'm interested and when I get to Phoenix next week I'll check out the video, I hope. Do they give you any details of how it works? I assume it's FM? or is it PM (phase modulated)? Do they even mention how it's modulated?

If they did the same for this as they did for WiFi in computers, then I'll have to check it out closer. In computers the wifi channels overlap and you have to have 6 channels of separation to ensure good performance. It would be refreshing to have something that actually works well instead of a compromise between the people interested in the frequency and spectrum width.

Any information would be nice if anyone remembers...

Thanks,

Jack

Hi Jack,
I encourage you to download the whitepaper from WiSAassociation.org website before or after you watch the video; it will answer a lot of your technical questions. WiSA technology uses the unlicensed DFS channels between 5.2 and 5.8 GHz, similar somewhat to 802.11a radios but WiSA is not WiFI, zigbee, or bluetooth speakers. These DFS channels are also used randomly for weather etc., so using them requires polling and frequency hopping, but there is always plenty of open channels, even at trade shows. I believe the audio modulation is PCM.
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post #19 of 20
3/22/13 at 1:09pm
Quote:
Originally Posted by PKaudiovisual View Post

I think I understand what you are asking, if it detects interference, how far away (in Hertz) does it jump to ensure it won't hit the same interference? The number of available (legal to use) DFS channels between 5.2 and 5.8 GHz varies per region, but one can expect roughly 14 DFS available channels in a given country. The WiSA technology follows the rules of DFS in that it constantly scans all of the DFS channels to see which are open and which are not. A channel has to be open and interference free for a minute before the system jumps to it, by law. The jump could be to an adjacent channel or the other end of the spectrum, depending on what channels are being used. The system learns what channels are really bad and avoids jumping back to them.

if you want to delve further, send an email to info@wisaassociation.org and we will put you directly in touch with Alan.

Exactly what I was asking! Thanks! Interesting that it even "learns" what channels to avoid. I really don't know much more on the subject to ask, but very informative video and I appreciate the response and email offer for more info. I'll certainly be keeping an eye on the technology for possible future projects (mainly thinking along the line of an outdoor set-up where this tech could allow me to not run wires). Thanks!
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post #20 of 20
3/27/13 at 8:40am
Although not RF, and not related to the WiSA evolving standard, folks here might find this of some interest: It is possible to piggy-back on legacy S/PDIF infrastructure, which most DVD players, receivers and many computer sound-cards still have, to wirelessly transmit (2 channels only) of 24bit/96kHz PCM uncompressed audio. This can be done using an OPTICAL (although it is obviously line-of-sight) link with inexpensive high-radiance red or IR-leds and very simple modulator/demodulator circuits which can support bit rates up to 50Mbps. The modulation is optical baseband PCM. I have assembled demo systems like this, transmitting perfectly over distances in excess of 100' to powered monitor speakers with coaxial S/PDIF inputs. In the optical regime, "antennas" are very inexpensive plastic or glass lenses. Since transmission is line-of-sight, it is easy to "go around corners" with inexpensive mirrors with a bit of basic optical alignment. Essentially no interference. A S/PDIF Free Space Digital Audio Optical Link
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