Re: [Sursound] wifi audio (was Re: Deconstructing soundbar marketing B.S.)
It should spell Sennheiser, still? ”Even” in America... https://en-us.sennheiser.com/mkh-microphones Best, Stefan - - - Citando Augustine Leudar : Thanks Chris - by multichannel I mean , basically, surround sound. So stereo is two channels - but it woiuld be nice to, for example, broadcast 8 or 16 seperate signals to 8 or 16 seperate speakers each 100 metres apart .I have used the senheizer in ear montitors to do things like this but you can only go fifty metres. I often have to run several km of cables at events to speakers and I would love not to have to - of course they still need power but we;ve previously got round this with several low power low noise portable IP6 rated generators. I was wondering why Senheizers had a short distance range but good sound whereas my walkie talkies could go very far but had crap audio - youve answered the question tx. On Thu, 30 May 2019 at 17:07, Chris Woolf wrote: Answering this specific question... On 30/05/2019 10:42, Augustine Leudar wrote: ... I had some walkie talkies that had a range of one KM with admitedly terrible audio (surely this could be improved) . Whereas Senheiser in ear monitors have a really short distance range of around 40 metres and use much higher electromagnetic frequencies ((863 mhz) . Why is it something cant be done with the same sort of range as the walkie talkies but for.multichammel audio (according to wikipedia 30 - 400 mhz) ? Walkie talkies run on a 12.5kHz narrow band, and need ~50kHz of channel space. Broadcast quality FM (as in radio mics) uses a channel space of ~250kHz. Given than channel "skirts" are quite a bit wider multiple local channels cannot sit close to each other, and are commonly spaced ~500kHz apart. They also have to avoid numerical frequencies which would cause intermodulation. Thus remarkably few analogue radio channels can fit into a single (8MHz) TV channel space. The usual answer is ~12 at best. Some claim more but range and mutual interference may suffer. With digital modulation this can improve to ~20 because the effects of interference are reduced. Range is directly related to bandwidth, transmission power, and RF signal-to-noise limitations of the receiver. Narrow band with limited audio bandwidth and restricted (audio) signal-to-noise is a much easier task with a couple of AA cells than 20kHz audio with 100dB (companded) dynamic range. Digital radio mics have been even harder to make that can modulate something that equates to full broadcast bandwidth and dynamic range into the the same 250kHz bandwidth as analogue, and with roughly the same range/battery power. I've no idea what the .multichannel audio is - can you elaborate? And I can't imaging that there is any spectrum clear in the 30-400MHz region. Chris Woolf www.magikdoor.net[1] +44(0)7555784775 -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20190530/de617fc8/attachment.html> ___ Sursound mailing list surso...@music.vt.eduhttps://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on. Ligações: - [1] http://www.magikdoor.net -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20190530/3b5012f9/attachment.html> ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
Re: [Sursound] wifi audio (was Re: Deconstructing soundbar marketing B.S.)
The RF issue of range, carrier frequency, channel width is quite separate from the deliverable audio path. The Opus audio codec has revolutionized audio coding. It's able to deliver full-bandwidth audio at bitrates not much more than what was once typical of a telephone call. This means that the RF band need not be large to deliver high quality audio over a digital link. There are a diverse range of wireless microphone and monitors. Some have multi-channel capability in support of unique pathways for the various artists in an ensemble. Their RF characteristics are made to match regulatory realities in different jurisdictions. Some are analog (ex. companded FM) others digital. To my knowledge, none are IP-based. There are folks in the HAM radio space using digital compression techniques to deliver wideband audio over extremely low-bitrate links. Think sub-3 kbps for voice. Michael Graves mgra...@mstvp.com http://www.mgraves.org o(713) 861-4005 c(713) 201-1262 sip:mgra...@mjg.onsip.com skype mjgraves -Original Message- From: Sursound On Behalf Of Chris Woolf Sent: Thursday, May 30, 2019 11:08 AM To: sursound@music.vt.edu Subject: Re: [Sursound] wifi audio (was Re: Deconstructing soundbar marketing B.S.) Answering this specific question... On 30/05/2019 10:42, Augustine Leudar wrote: > ... I had some walkie talkies that had a range of one KM with > admitedly terrible audio (surely this could be > improved) . Whereas Senheiser in ear monitors have a really short > distance range of around 40 metres and use much higher electromagnetic > frequencies > ((863 mhz) . Why is it something cant be done with the same sort of > range as the walkie talkies but for.multichammel audio (according to wikipedia > 30 - 400 mhz) ? Walkie talkies run on a 12.5kHz narrow band, and need ~50kHz of channel space. Broadcast quality FM (as in radio mics) uses a channel space of ~250kHz. Given than channel "skirts" are quite a bit wider multiple local channels cannot sit close to each other, and are commonly spaced ~500kHz apart. They also have to avoid numerical frequencies which would cause intermodulation. Thus remarkably few analogue radio channels can fit into a single (8MHz) TV channel space. The usual answer is ~12 at best. Some claim more but range and mutual interference may suffer. With digital modulation this can improve to ~20 because the effects of interference are reduced. Range is directly related to bandwidth, transmission power, and RF signal-to-noise limitations of the receiver. Narrow band with limited audio bandwidth and restricted (audio) signal-to-noise is a much easier task with a couple of AA cells than 20kHz audio with 100dB (companded) dynamic range. Digital radio mics have been even harder to make that can modulate something that equates to full broadcast bandwidth and dynamic range into the the same 250kHz bandwidth as analogue, and with roughly the same range/battery power. I've no idea what the .multichannel audio is - can you elaborate? And I can't imaging that there is any spectrum clear in the 30-400MHz region. Chris Woolf --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on. ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
Re: [Sursound] wifi audio (was Re: Deconstructing soundbar marketing B.S.)
Thanks Chris - by multichannel I mean , basically, surround sound. So stereo is two channels - but it woiuld be nice to, for example, broadcast 8 or 16 seperate signals to 8 or 16 seperate speakers each 100 metres apart .I have used the senheizer in ear montitors to do things like this but you can only go fifty metres. I often have to run several km of cables at events to speakers and I would love not to have to - of course they still need power but we;ve previously got round this with several low power low noise portable IP6 rated generators. I was wondering why Senheizers had a short distance range but good sound whereas my walkie talkies could go very far but had crap audio - youve answered the question tx. On Thu, 30 May 2019 at 17:07, Chris Woolf wrote: > Answering this specific question... > > On 30/05/2019 10:42, Augustine Leudar wrote: > > ... I had some walkie talkies that had a > > range of one KM with admitedly terrible audio (surely this could be > > improved) . Whereas Senheiser in ear monitors have a really short > distance > > range of around 40 metres and use much higher electromagnetic frequencies > > ((863 mhz) . Why is it something cant be done with the same sort of range > > as the walkie talkies but for.multichammel audio (according to wikipedia > > 30 - 400 mhz) ? > > Walkie talkies run on a 12.5kHz narrow band, and need ~50kHz of channel > space. Broadcast quality FM (as in radio mics) uses a channel space of > ~250kHz. Given than channel "skirts" are quite a bit wider multiple > local channels cannot sit close to each other, and are commonly spaced > ~500kHz apart. They also have to avoid numerical frequencies which would > cause intermodulation. Thus remarkably few analogue radio channels can > fit into a single (8MHz) TV channel space. The usual answer is ~12 at > best. Some claim more but range and mutual interference may suffer. With > digital modulation this can improve to ~20 because the effects of > interference are reduced. > > Range is directly related to bandwidth, transmission power, and RF > signal-to-noise limitations of the receiver. Narrow band with limited > audio bandwidth and restricted (audio) signal-to-noise is a much easier > task with a couple of AA cells than 20kHz audio with 100dB (companded) > dynamic range. Digital radio mics have been even harder to make that can > modulate something that equates to full broadcast bandwidth and dynamic > range into the the same 250kHz bandwidth as analogue, and with roughly > the same range/battery power. > > I've no idea what the .multichannel audio is - can you elaborate? And I > can't imaging that there is any spectrum clear in the 30-400MHz region. > > Chris Woolf > > > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > > ___ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, > edit account or options, view archives and so on. > -- Dr. Augustine Leudar Artistic Director Magik Door LTD Company Number : NI635217 Registered 63 Ballycoan rd, Belfast BT88LL www.magikdoor.net +44(0)7555784775 -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20190530/de617fc8/attachment.html> ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
Re: [Sursound] wifi audio (was Re: Deconstructing soundbar marketing B.S.)
Answering this specific question... On 30/05/2019 10:42, Augustine Leudar wrote: ... I had some walkie talkies that had a range of one KM with admitedly terrible audio (surely this could be improved) . Whereas Senheiser in ear monitors have a really short distance range of around 40 metres and use much higher electromagnetic frequencies ((863 mhz) . Why is it something cant be done with the same sort of range as the walkie talkies but for.multichammel audio (according to wikipedia 30 - 400 mhz) ? Walkie talkies run on a 12.5kHz narrow band, and need ~50kHz of channel space. Broadcast quality FM (as in radio mics) uses a channel space of ~250kHz. Given than channel "skirts" are quite a bit wider multiple local channels cannot sit close to each other, and are commonly spaced ~500kHz apart. They also have to avoid numerical frequencies which would cause intermodulation. Thus remarkably few analogue radio channels can fit into a single (8MHz) TV channel space. The usual answer is ~12 at best. Some claim more but range and mutual interference may suffer. With digital modulation this can improve to ~20 because the effects of interference are reduced. Range is directly related to bandwidth, transmission power, and RF signal-to-noise limitations of the receiver. Narrow band with limited audio bandwidth and restricted (audio) signal-to-noise is a much easier task with a couple of AA cells than 20kHz audio with 100dB (companded) dynamic range. Digital radio mics have been even harder to make that can modulate something that equates to full broadcast bandwidth and dynamic range into the the same 250kHz bandwidth as analogue, and with roughly the same range/battery power. I've no idea what the .multichannel audio is - can you elaborate? And I can't imaging that there is any spectrum clear in the 30-400MHz region. Chris Woolf --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
Re: [Sursound] wifi audio (was Re: Deconstructing soundbar marketing B.S.)
le/environments must be > <<5ms. > > I find it laughable that "low latency" frequently seems to mean 30-50ms. > > > > Chris Woolf > > > > > > > > --- > > This email has been checked for viruses by Avast antivirus software. > > https://www.avast.com/antivirus > > > > ___ > > Sursound mailing list > > Sursound@music.vt.edu > > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe > > here, edit account or options, view archives and so on. > > ___ > > Sursound mailing list > > Sursound@music.vt.edu > > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe > > here, edit account or options, view archives and so on. > > > -- next part -- An HTML attachment was > scrubbed... > URL: < > https://mail.music.vt.edu/mailman/private/sursound/attachments/2019052 > 9/54bacb40/attachment.html > > > ___ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe > here, edit account or options, view archives and so on. > -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20190530/33d69a2e/attachment.html> ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on. ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
Re: [Sursound] wifi audio (was Re: Deconstructing soundbar marketing B.S.)
Le 30/05/2019 à 00:47, David Pickett a écrit : At 22:52 29-05-19, you wrote: Distribution to speakers using UDP multicast of a multichannel stream could possibly make the only time difference between channels be eventual receiver buffering. Just speculation... Bo-Erik UDP would basically help to reduce the latency, but in a noisy environment it could help to use TCP (if latency is less of an issue). Fons created Zita-njbridge to build a multi-channel networked system; according to the description: " Zita-njbridge can be used for a one-to-one connection (using UDP) or in a one-to-many system (using multicast). Sender and receiver(s) can each have their own sample rate and period size, and no word clock sync between them is assumed. Up 64 channels can be transmitted, receivers can select any combination of these. On a lightly loaded or dedicated network zita-njbridge can provide low latency (same as for an analog connection). Additional buffering can be specified in case there is significant network delay jitter." It was reported to work better with 24 bit streams: http://qrqcwnet.ning.com/profiles/blogs/remote-rig-audio-over-ip-using-zita-njbridge-16-bit-verses-24-bit But the question is whether it would be a fixed value and predictable, and thus correctable. The "no world clock sync assumed" feature of Zita-njbridge is puzzling... Marc ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
Re: [Sursound] wifi audio (was Re: Deconstructing soundbar marketing B.S.)
On Wed, May 29, 2019 at 09:32:02PM +0100, Paul Hodges wrote: > My concern with > wi-fi latency when multiple links are required to multiple speakers > would be that the latency will not be consistent between channels. > Although buffering will keep the data flow going, there is no way to > ensure that the buffering in each data stream is near-enough the same > as required for phase accuracy. That is not a real problem. If all channels are tranmitted in a single multichannel broadcast (as opposed to having separate single-channel links), all receivers will see exactly the same timing of received packets even if that timing is irregular. Then if all of them use the same algorithm to filter the timestamps (i.e. to obtain a smooth linear relation between the local clock and the sample index), they will be synced. It just requires careful design. The basic requirement to make this work is that the RF part provides accurate timestamps on received packets (compensated for any RF processing delay), using a clock which is coherent with the local audio sample clock. Ciao, -- FA ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
Re: [Sursound] wifi audio (was Re: Deconstructing soundbar marketing B.S.)
du > > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, > > edit account or options, view archives and so on. > > > -- next part -- > An HTML attachment was scrubbed... > URL: < > https://mail.music.vt.edu/mailman/private/sursound/attachments/20190529/54bacb40/attachment.html > > > ___ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, > edit account or options, view archives and so on. > -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20190530/33d69a2e/attachment.html> ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
Re: [Sursound] wifi audio (was Re: Deconstructing soundbar marketing B.S.)
On Wed, May 29, 2019 at 05:55:49PM +0200, Wim wrote: > The major problem with wireless lays in the re-authentication that occurs > after a preset period. That takes up to several hundred millisecs. That's one problem. Another one is that you won't be alone on the channel. A quick scan here (Munich suburb) reveals 30 users on what (in the 2 GHz band) amounts to 4 non-overlapping channels. Ciao, -- FA ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
