Future: Wireless mics choosing own frequencies

[andrew gissing]

Hi,

This posted on the reg today:

http://www.theregister.co.uk/2011/10/28/cognitive_radio/

A quote of one paragraph:

The idea is to have sensors spread around a venue, constantly monitoring the available channels (a list of which comes from the White Space database), wireless microphones being used on stage can then be notified before interference builds up enough to impact with the audio stream, allowing the microphones to switch channels without interruption. An audience member suddenly switching on an impolite White Space device might still cause problems, necessitating an immediate jump, but any brought into the venue or building up from outside could be detected and avoided without affecting the performance.

For your edification....

Henry/Karl - any comment ?



Andrew

 

[Jason Lavoie]

Re: Future: Wireless mics choosing own frequencies

Hi,

This posted on the reg today:

http://www.theregister.co.uk/2011/10/28/cognitive_radio/

A quote of one paragraph:

The idea is to have sensors spread around a venue, constantly monitoring the available channels (a list of which comes from the White Space database), wireless microphones being used on stage can then be notified before interference builds up enough to impact with the audio stream, allowing the microphones to switch channels without interruption. An audience member suddenly switching on an impolite White Space device might still cause problems, necessitating an immediate jump, but any brought into the venue or building up from outside could be detected and avoided without affecting the performance.

For your edification....

Henry/Karl - any comment ?



Andrew

The future is here.... http://www.axient.net/en/
all except for the whitespace database lookup, but that would just be a firmware update to add that..

Axient constantly scans and keeps a list of good frequencies, and can remotely switch a transmitter over in a split second (barely detectable during a speech)
and if you go frequency dversity each transmitter can transmit on two channels simultaneously and the receiver can ditch the bad one and reassign a new one before you even noticed a problem!

Jason

 

[Christian Tepfer]

Re: Future: Wireless mics choosing own frequencies

The future is here.... http://www.axient.net/en/
all except for the whitespace database lookup, but that would just be a firmware update to add that..

Axient constantly scans and keeps a list of good frequencies, and can remotely switch a transmitter over in a split second (barely detectable during a speech)
and if you go frequency dversity each transmitter can transmit on two channels simultaneously and the receiver can ditch the bad one and reassign a new one before you even noticed a problem!

Jason

Yeah, halfway there. Because with frequency diversity on you lose close to half of the good frequencies.

Frequency diversity is no solution for massive rf channel counts but great for maximum rf stability in low to medium channel counts.

 

[Bennett Prescott]

Re: Future: Wireless mics choosing own frequencies

Frequency diversity is no solution for massive rf channel counts but great for maximum rf stability in low to medium channel counts.

Well, and there are RF channels and then there are critical RF channels. I doubt anyone is going to run every mic on two channels, but lead vocal might be worth it.

On the AES show floor the Axient system was able to locate 45 good channels, in the middle of Javits, with God knows what kind of RF energy in the city and at least one other RF manufacturer running a few channels as well. That's with a pair of omni antennas, too. I think that exceeds most people's channel count needs.

 

[Christian Tepfer]

Re: Future: Wireless mics choosing own frequencies

Well, and there are RF channels and then there are critical RF channels. I doubt anyone is going to run every mic on two channels, but lead vocal might be worth it.

On the AES show floor the Axient system was able to locate 45 good channels, in the middle of Javits, with God knows what kind of RF energy in the city and at least one other RF manufacturer running a few channels as well. That's with a pair of omni antennas, too. I think that exceeds most people's channel count needs.

Good point, Bennett. There may be some gigs where more channels should be run frequency diversed, like corporate gigs, where people really don't like being silenced by technology. And don't like to switch off their blackberries ;-)

Anyway, as spectrum is getting more valuable, us competing with broadband network over the air and narrowband services as well, solutions like Axient are very welcome. Pretty big jump for Shure, after being stuck with the U series for years. They are now up to date, rf-wise.

 

[Jason Lavoie]

Re: Future: Wireless mics choosing own frequencies

Yeah, halfway there. Because with frequency diversity on you lose close to half of the good frequencies.

Frequency diversity is no solution for massive rf channel counts but great for maximum rf stability in low to medium channel counts.

the important part to note here is that even without frequency diversity (which has been available before, just without the automation) the worst possible case of interference will only interrupt the signal for a split second. it's so fast that unless the mic is the only signal that's on, or if it's your lead vocal you'd be hard pressed to notice.

this brings up an interesting point though, I wonder if the frequency diversity is quick to turn on and off, like say for solos

Jason

 

[Karl Winkler]

Re: Future: Wireless mics choosing own frequencies

Hi,

This posted on the reg today:

http://www.theregister.co.uk/2011/10/28/cognitive_radio/

A quote of one paragraph:

The idea is to have sensors spread around a venue, constantly monitoring the available channels (a list of which comes from the White Space database), wireless microphones being used on stage can then be notified before interference builds up enough to impact with the audio stream, allowing the microphones to switch channels without interruption. An audience member suddenly switching on an impolite White Space device might still cause problems, necessitating an immediate jump, but any brought into the venue or building up from outside could be detected and avoided without affecting the performance.

For your edification....

Henry/Karl - any comment ?



Andrew

Andrew, I would agree that cognitive radio is where things are headed. The challenges of continually eroding spectrum coupled with the increasing sophistication of the wireless microphone systems makes this inevitable. I think Shure is on the right track with Axient, as others have mentioned. Whether or not is becomes a "standard" is hard to say - there are too many factors. But Kudos to Shure for putting in the R&D to bring out a next-generation product like this.

RE: white space devices or TVBDs (TV band devices), don't forget that their energy is spread over a wider bandwidth, so they will not look like competing wireless mics in a scan. However, they will look like a rising noise floor. Next is the protections put in place by the FCC for wireless mic users. It won't be too long before we see all of this technology incorporated into new systems - perhaps 3-5 years. There's no question that spectrum will continue to become more valuable and more devices will want access.