[berdelyi]

I've had a Blackberry in the past and now and iPhone. Both of these devices seem to create alot of interference near speakers that creates a unique clicking and buzzing sound. This is almost like ESP since the devices will start to "talk" through the speakers with clicks and buzzes moments before I get an SMS text message, email or phone call.


What exactly is this interference?


I plan to create a home run location in a closet to house all my A/V, networking, telecom, cable and automation equipment. I'll also be running the speaker wires through conduits so I can install speakers in the ceilings and walls.


What should I be doing to prevent this kind of interference?

 

[WilliamZX11]

Not sure what it is, but I have experienced it. My PC speakers will make noises just before the cell phone rings.


And though I have no audible clicks or noise in my main systen, whenever a call is placed on a cell from that room, the subwoofer auto power kicks on.

 

[jayrader]

Keep your phone out of the theater / listening room. It makes baby jesus cry.

 

[speco2003]

Sometimes you will even hear it happen on live TV shows. The guest or some bozo has a cell phone close the wireless system.

 

[Speedskater]

Cell-phones send digital information in packets. Often at 217 times per second. This may cause small DC shifts in more sensitive circuits, result is a buzzing sound.

 

[Rasterfarian]



Quote:
Originally Posted by berdelyi /forum/post/14169466


What exactly is this interference?


What should I be doing to prevent this kind of interference?

It's the modern digital version of good old-fashoned RFI - Radio-Frequency Interference. If it comes from a powerful nearby AM radio station, you can hear the program material. If it's a digital signal, it will be buzzes and squawks.


What can you do? Don't put a radio transmitter next to your A/V wiring and equipment. Cell phones, cordless handsets and base stations, wireless networking and bluetooth devices all use transmitters, so keep those out of your wiring closet and away from equipment. They are not very powerful, so the distances don't have to be great; you can probably find out a good working minimum by experimenting if you're interested.


Because they broadcast over radio, I've always been skittish about using cordless equipment of any type when discussing sensitive matters. With digital equipment it's not as easy to eavesdrop as it used to be (in the analog days it was stump simple), but still possible. I always use a wired telephone for calls involving credit cards, bank account numbers, passcodes, etc. Seems an elementary, if not foolproof, precaution. YPMV (Your Paranoia May Vary).

 

[speco2003]

Also I "think" depending on how well shielded things are is a big player. We have a set of Yamaha MSP5 speakers on my desk. The cell phone makes those buzz. There is a set of Meyer HD1s close as well. We have never been able to get them to buzz.

 

[speco2003]

We have racks of gear that has wireless routers along with macs broadcasting blutooth along with patchbays and protools rigs. We have zero problems with any of that talking to each other or buzzing. Nothing is fancy as far as cables go or any other units.

 

[berdelyi]

Thank you everyone for the tips.


So is the interference going to be with the receiver or the speakers or along the speaker wires in the walls and ceiling?


I do intend on having a wireless access point in the wiring closet (though I've never had interference with this in the past).


Where can I look for more details on interference with from Blackberries and iPhones (I know about Google, but are there any specific sources you'd recommend)?

 

[Greg_R]

It has nothing to do with your Blackberry or iPhone... this happens with ALL cell phones (specifically before an in-bound call or when your phone is sync'ing information like voice mail notifications). It will affect all the things that you listed because the speaker wiring is unshielded (and is attached to the receiver and speakers). Plus, there is unshielded wire inside the speaker and receiver. The receiver is likely inside a metal box which acts as a nice shield but the speaker is not.


Bottom line: keep your phones away from your electronics. Alternatively re-wire your receiver, speaker, and system with shielded cable (not really a viable option)

 

[Speedskater]

For more information is:

"Avoiding ESD and EMI hazards in mobile phone audio interfaces"
http://www.audiodesignline.com/howto/portableaudio

 

[Jonomega]

Here is a solution for the iphone. I don't know about the Blackberry though...

 

[filecat13]



Quote:
Originally Posted by Greg_R /forum/post/14209707


Alternatively re-wire your receiver, speaker, and system with shielded cable (not really a viable option)

I'll get right on it.

 

[filecat13]



Quote:
Originally Posted by Jonomega /forum/post/14219868


Here is a solution for the iphone. I don't know about the Blackberry though...

Forget something in your post?

 

[berdelyi]

The smiley is the youtube link.


I understand this is not unique to Blackberries or iPhones and applies to all GSM (and maybe other) devices.


Since I'm running speakers and speaker wires throughout my home it's not a practical option to ban these devices in my home.


Using shielded wiring is an option for me. Is this all it will take? Do you have recommendations on what to look for in shielded speaker wiring?


Are you saying if I use shielded wiring it doesn't matter what's on the end of those wires?

 

[speco2003]



Quote:
Originally Posted by berdelyi /forum/post/14221985


The smiley is the youtube link.


I understand this is not unique to Blackberries or iPhones and applies to all GSM (and maybe other) devices.


Since I'm running speakers and speaker wires throughout my home it's not a practical option to ban these devices in my home.


Using shielded wiring is an option for me. Is this all it will take? Do you have recommendations on what to look for in shielded speaker wiring?


Are you saying if I use shielded wiring it doesn't matter what's on the end of those wires?

Is this really that big of a deal? If the phone is off or not near the system it is not a issue. In fact on my home system this has never been a issue. We have 4 cell phones in the house all over. At work here it only happens when the guy who has the MSP5s on his desk has his phone on his desk next to thme. The other 6 phones in the office which is about 30X30 do not cause any issues. You are making a mountain out of a very small ant hill.

 

[berdelyi]

I am installing a home automation and control system which will include audio distribution. Since I'll have speakers in every room with speaker wires back to the A/V equipment I think this could be a serious concern.


I don't want speakers in one room buzzing because a guest in another room is receiving a phone call or txt message.


I've been in meeting rooms and at conferences with hundreds of people that experience annoying interference from just one phone.


If I go through the time and expense of running all of this I want to do it properly and avoid as much interference as possible without limiting the usage of phones.

 

[speco2003]



I've been in meeting rooms and at conferences with hundreds of people that experience annoying interference from just one phone.

QUOTE]


That one phone was more than likely someone sitting very close to the gear. Like the guy running it or one of the folks speaking. I have seen that many times as a audio engineer. Someone sitting in the room as a listner is really not the issue.


And if everything is behind walls in your house this really wont be a issue either.