3G Phones and live sound

[Biskit]

Hi Guys,

 

A few years ago, the advice regarding 'old' (G2) mobile phones was to switch off when close to sound equipment (especially in a live PA setting) to avoid the familiar "beep bee-ba-beep bee-ba-beep" sound being induced in nearby signal cabling whenever a message or call comes through.

 

However I've never actually had an issue with this, as long as all audio links are kept balanced and the phone is kept away from the mixer's master section, for example.

 

Does anyone know whether 3G signals are any more or less likely to cause this effect? I have a 3G broadband modem which I assume sends and receives high bandwidth signals just about constantly while browsing the web. Is this likely to cause a problem close to sound gear? I've not had a problem in 'testing' but it'd be sod's law that on the first gig... :D

 

Any experiences?

 

Ben.

[mutley]

Does anyone know whether 3G signals are any more or less likely to cause this effect? I have a 3G broadband modem which I assume sends and receives high bandwidth signals just about constantly while browsing the web. Is this likely to cause a problem close to sound gear? I've not had a problem in 'testing' but it'd be sod's law that on the first gig... :)

 

Any experiences?

 

Ben.

 

Hi Ben

 

I think it probably depends more on the phone/modem device than whether it's 3G or the network it uses...

 

I used to set my laptop up directly on top of the sound desk (OK, it was a metal SoundCraft Spirit, so inherently screened in its construction), but even with my laptop connected to the internet by Vodafone or T-Mobile datacards, whether by GPRS, UMTS or HSDPA (57k, 385k or 1.8Mb) I still got ZERO interference.

 

My boss's phone however, gave the well-known "Sinclair Spectrum loading a game" noise over the PA, which was actually a good thing, coz she stopped coming over to the tech area and hassling us (and was unable to tell just how hung over/drunk all the technicians really were! :D )

[stagemanagement]

Definitely an individual phone issue and ot one of 3G versus older phones.

I've been leaving my Samsung phones on the desk for years and NEVER had interference from it.

 

Nokia's can be a pain for it though, especially when the Lampy sticks his in the two inch gap between the desks!

[mostlyharmless]

The 3G spec transmits below background noise. Meaning that you can transmit lots of data streams and each stream just looks like noise to the others. Therefore, I doubt it would have a strong effect on any audio kit as it would see it as a pretty steady broadband signal. Try to keep things balanced as ever though!

[dave_m]

Not live sound I know, but Iphones and Blackberries are terrible on comms, whereas my G1 creates next to no interference. So it appears to be a phone based issue! Unless there's something with comms that makes them more susceptible?

[smalljoshua]

Tecpro/Clearcom Comms are unbalanced. I have a Samsung Omnia which causes no interference on either balanced or unbalanced signal lines.

[Chris Beesley]

My iphone 3G still manages to cause chaos when placed near certain items of the PA... :D

[charlyfarly]

OK. Some of you are not going to like this and it may seem harsh......but why not turn your phones off and put them on voicemail only during a performance. This should apply to performers and crew alike (apart from the production/tour manager and hopefully he or she is ensconced in an office somewhere.).

It's not that hard to be "out of contact" for a couple of hours. My, how did we cope in the Dark Ages :D

[Pete McCrea]

I'll echo Chris Beesley on the iPhone 3G- causes chaos with comms. And it is usually off or in Aircraft mode while in the show, but on during rehearsals...

[Rob_Beech]

I'll echo Charly, for tis the right thing to do.

 

I must admit, having only a very simple phone that does what I need, I rarely get any issues like this. However last week I did put my phone under the VCA faders on the ML3000 and.... that DID make a noise. Luckily it was whilst setting up, I wouldn't have had it there during the show anyway.

[Gareth Owen]

I have a blackberry (the big black square ugly looking one) which causes massive interference with Clearcom / ASL but which lives happily alongside RTS. It also causes huge problems next to unbalanced cables but is troublefree next to balanced ones.

[Paul TC]

The other point to consider is that in the absence of a 3G network signal, the phone will "fallback" to a GSM/GPRS network and hence the type and frequency of the RF signal will change.

[stagemanagement]

OK. Some of you are not going to like this and it may seem harsh......but why not turn your phones off and put them on voicemail only during a performance. This should apply to performers and crew alike (apart from the production/tour manager and hopefully he or she is ensconced in an office somewhere.).

It's not that hard to be "out of contact" for a couple of hours. My, how did we cope in the Dark Ages :D

 

 

I can't see the Comms flashing for the strobes!!!!!!!!!!!!!! :)

Phone's the only way for Monitor World to raise me half the time!

[sleah]

Bump!

 

Mmmm... in my experimentation I got 'the sound' when holding a phone against a VHF lapel transmitter, but nothing against a UHF......

 

Now, something I've always wondered. Is it possible for phones to cause problems with radio mics, not sound related, but reducing the range or causing drop outs of the signal.

You know during a big song in a musical and the lead mic drops for half a second, which may as well be half an hour!!!

You do a test before the next performance and can't reproduce the fault for love nor money?

Oh, I'm talking all lapels here...

The main difference, apart from 200 bodies, is some ;) 's will have left their phones on :)