Battling iPhone's GSM Buzz 3: Behringer MS40 Digital

Edit: This is the third in a series of four articles on Battling iPhone’s GSM Buzz. A solution to this issue is described in the fourth installment.

Here is what I hope will be the final installment of my Battling iPhone’s GSM Buzz series. It has become somewhat of an abiding obsession to outfit my G5 workstation with speakers that don’t go rat-a-tat-tat every time my iPhone wants to talk to a cell tower. You readers have been very helpful with your suggestions, and I hope you’ve gotten some use out of my commentary (even if it’s only Schadenfreude or commiseration).

Martin started me off on a new angle, and I commenced a search for a pair of computer speakers that could make use of my G5’s optical audio out. I found them for a slight premium over my original budget of $100 in the Behringer MS40 Digital Monitor Speakers. American Musical Supply have them for $129 through Amazon. I also picked up an inexpensive digital optical cable from them, since they had free shipping on orders of $50 or more.

I have to say I was impressed with the service of AMS. I contacted Behringer directly about GSM buzz, and received no response. I repurposed my email to AMS and heard a reply within a day. They even responded to a follow-up. Here’s how it went:


I was wondering if the digital coaxial and/or digital optical
interface of the Behringer MS20 and MS40 multimedia speakers does anything to alleviate interference from GSM  mobile phones (GSM Buzz). I currently have a Mac tower and a docked iPhone in my studio, and the phone has caused significant interference with all analog speakers I’ve tried. See discussions here and here.

I did see the below instructions from the manufacturer, and wondered if a GSM mobile phone counted as a high-frequency source. I also have 802.11 wifi at home, and wonder if that would interfere.

IMPORTANT NOTES CONCERNING INSTALLATION: The sound quality may diminish within the range of powerful broadcasting stations and high-frequency sources…


Optical connections use light channeled through a fiberoptic cable and radio/cell phone transmissions should not affect it.  If you are experiencing gsm buzz you may want to check your cables and make sure they have sufficient shielding/insulation.  You may want to make sure the electrical outlets have proper grounding as well.

Well, this was the first I’d heard of checking the electrical outlets for proper grounding. As for the shielded cables, I could see this was leading to a recommendation that I drop another C-note on Monster-branded cables, and all I see on audiophile sites is hate for their price/quality quotient.

As for the Behringer MS40 digital monitors, I was willing to give optical a try. Especially if the risk was only $29.99 over my initial $100 budget (list, for what it’s worth, is $196.49). Sure, the MS20s (20 watt vs. 40 watt) were also on sale for $87.95, but I’m a sucker for the extra power. So I punched the purchase button on a Friday, and got the box the next Monday.

Speaking of which, I’ve been very impressed by how quickly Amazon (and now AMS) has delivered my packages to NYC (every time for free), and also how quickly my returns and refunds have been completed. Both the Klipsch and the M-Audio have been returned and refunded as I write this. Shipping and returning have all beat their time estimates by several days. It might be because I’m in a huge city, or it might be a case of underpromising and overdelivering. Either way, the lesson is that Super Saver shipping is quite sufficient, and all those inducements to pay extra for expedited shipping is usually a waste.

Okay, so this time the box was huge. My mailroom at work wrapped it with string so I could carry it to the train. I’m a big guy, and this tested my upper body strength. I switched carrying arms about a dozen times in the four blocks I had to walk. When I got home, I unpacked two substantial wooden cabinets, 11 inches tall, 9.625 inches deep, and almost 7 inches wide. That’s some serious desk real estate—I won’t deny it.

One thing I want to immediately point out about connecting optical cables to your mac is that the volume controls on the keyboard do not work unless you mute the sound entirely. The volume has to either be controlled through your apps or through the knob on the right speaker.  Maybe there’s some plugin I’m missing and one of you can set me straight.

I tested the speakers on a variety of music, and they’re awesome. All the detail I discovered in the M-Audio Studio Pro 3s was there and more. The high- and mid-frequency sounds are very much in the foreground, and while the bass is strong, it appears to reside more in the background. This is not to say there is a lack of bass here for a 2.0 system—quite to the contrary, it has the most of any I’ve tested—but I don’t want to get the inevitable hate mail about how subwoofers are the only way to get proper bass.

There is so much detail in the sound that I actually found myself nitpicking flaws in the music. On live classical tracks, you can hear the odd cough in the hall. On hip-hop tracks, you can hear where some samples don’t quite connect. I suppose that is because these are proper studio monitors, not consumer-grade "speakers" which may smooth-over some detail in service of a more balanced "mix."

You have to be careful with the volume on the MS40s. I never got any distortion, but they definitely "go to 11." The sound is so enveloping that you could actually endanger your hearing. I had some mild ringing in my ears after testing through my library for an hour or so. I don’t want chronic tinnitus, so I’ll be keeping the volume at a reasonable level from now on.

I heard no GSM buzz at all from the right speaker, which is the one that has the optical input. The left, however, didn’t take long. Here’s my next note to AMS: 


I’ve installed the MS 40 speakers, and the right speaker has no buzz. The RCA cable connecting the speaker appears to be cheaply made, and I am getting a little buzz on the left side. Can you recomme

nd a good shielded RCA cable in the 3′ range? What should I look for in a shielded RCA cable?


I would suggest the following…–i-MON-I1001M.html

Argh. The dreaded Monster cable recco. I went over to Radioshack, because I didn’t want to pay shipping, and I picked up a shielded RCA cable. I demurred on the Monster for $30, and got a house brand "Gold Series" stereo audio cable for about $17. And it was a waste of time and money. No change in the buzz on the left. I may try the Monster, but I really don’t hold out any hope. If it really could make a difference, I’m sure one of you will weigh in.

Maybe there’s something to AMS’s "Properly-Grounded Outlet" hypothesis. I’ve got a couple of upcoming projects around the house for the local electrician, and I’ll make sure he takes a look. In the meantime, that first attribute of the MS40s that I told you about—the weight—is what will keep them on my desk. They’re too heavy to return. The buzz is certainly a lot less than the Klipsch or Logitech speakers, and maybe a new wall outlet will make everything all right in the end. Plus, my arms are tired.

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