Why do I always hear static on hold?
October 4, 2005 6:47 AM   Subscribe

Why do I frequently hear static on hold? It doesn't happen every time, but enough that I think there's a reason behind this phenomenon.

Bad music will fade in and out with static but when someone answers the phone it's clear as a bell, so it can't be a bad connection. It's happened when I've called different companies over the years, so it can't be the case of one company with an AM radio stuck in the phone closet.

It seems odd to me that companies would spend money on a nice on-hold queue, and then never notice that their music has annoying static.
posted by revgeorge to Technology (9 answers total) 1 user marked this as a favorite
 
Best answer: Are you using a mobile phone? The data compression may cause the quiet and not-very-speech-like music to be reproduced very poorly, whilst voices which tend to be louder, and what the compression algorithms are intended for, will be reproduced with considerably greater clarity.
posted by edd at 7:21 AM on October 4, 2005


It seems odd to me that companies would spend money on a nice on-hold queue, and then never notice that their music has annoying static. - revgeorge

Keep in mind that people who answer the phones don't hear the hold music. I had worked here a year before I even knew people heard music while they were on hold.
posted by raedyn at 8:18 AM on October 4, 2005


Often the "hold music" is just an old radio in the server room hooked up to the phone system. Static can come from the fact that it's in an enclosed, interference-filled computer room, or from the radio drifting out of tune. As raedyn says, nobody who works there hears the hold music, so if the radio is slightly detuned, they probably won't notice.

I'd be interested to know whether this happens more with large companies with the "your call is important to us" insincerity generators, or with the small guys that probably are using the radio.
posted by pocams at 8:28 AM on October 4, 2005


Response by poster: I should add that I also discount the radio explanation because if I heard a DJ I would write it off as a cheap radio.

edd - I'm usually on a mobile phone, but I recall this happening on a landline. I'm going to test it out by calling a known-good source of music and see if I get static.

I wonder if a compression algorithm might be the cause, though, for call centers located halfway around the world...
posted by revgeorge at 8:52 AM on October 4, 2005


revgeorge: could be a possibility. I figure it's a compression figment, because I've heard the static level change very suddenly which makes me think I'm hearing the transition to another segment of compressed sound. If the static fades in and out smoothly then my suggestion seems less likely to explain it in your case though.
posted by edd at 9:03 AM on October 4, 2005


Many on-hold systems use radio-based systems like Muzak (yes, they're a real company). I remember that the old office I worked at had a Muzak box in the phone closet that was hooked up to an antenna on the roof. If there was poor reception, you definitely would get static.
posted by zsazsa at 10:32 AM on October 4, 2005


Best answer: edd was partially right.

Most phone systems these days are digital. To keep bandwidth down to a minimum, they have something called "silence detection" that takes a running averge of the phone connection and cancels out the really really quiet parts ... that's why the sound of typing is never heard while the person on the other end is quiet, but then when they speak you hear all the background noise.

In the case of music-on-hold (sometimes radios, sometimes mp3 players hooked into the phone system, sometimes professional muzak systems), the running average screws up the quiet parts of the sound and the algorithm gets all screwed up, resulting in a bunch of static. I had this problem when I was setting up an asterisk system for the first time.
posted by SpecialK at 11:02 AM on October 4, 2005


Could it be "comfort noise generation" (CNG)? Your cell phone, for example, locally generates a bit of synthetic noise during silent periods to let you know that the radio connection is still "up" and enable conservation of radio bandwidth at the same time. I believe some VoIP systems do this too.
posted by ZenMasterThis at 7:44 PM on October 4, 2005


SpecialK - were you able to find a way around it?
posted by afroblanca at 9:21 PM on October 4, 2005


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