Noice Reduction/Cancellation -- Office Environment

[jon]

Just to be clear, if the problem is speech etc. I don't think active 'noise reduction' phones such as Bose make will be much help - their designed to block out more the noise from fans, engines etc (i/e/ just what you'll be playing through them!). You'll probably be much better with passive noise blocking phones - the over-ear sennheisser ones that were mentioned might be good, or koss do some cheap in-ear ones...or etymotic some sub-$100 in-ear phones. Given they won't be used for music, I'd go for the cheap option

 

[jj]

First, cancellation works on stationary sorts of noise, those for which the characteristics don't change much. In other words, about the opposite of key clicks.

Second, cancellation in headphones only works at low frequencies. Due to a whole bunch of issues, once you have about 1/10 of a wavelength between the sensing microphone and the driver that's doing the cancellation, that's about all you can do. (This has to do with stability of the system, changes in the soundfield with distance, etc.)

For a headset with a mike 1" from the headphone driver, that puts you at about 10" wavelength.

1153*12 in/second / 10" = 1300Hz... At best.

Sorry, yes, it would be nice, wouldn't it?

 

[Piggy]

First, cancellation works on stationary sorts of noise, those for which the characteristics don't change much. In other words, about the opposite of key clicks.

Second, cancellation in headphones only works at low frequencies.

This point has come up a few times here, in various forms, and it was my concern in point #1 in the OP.

That's why online/print reviews by people who use noise-reducing headphones for travel or industry don't really help me, and why I'd thought to try a model designed for noise reduction by means other than cancellation.

Trouble is, I have no idea if -- or how well -- any of the designs work. And you can probably deduce from my job description that I'm not likely to accept a company's marketing claims unless I can verify them independently.

The Etymotics seem designed for listening, and the Sennheiser use noise-cancellation. So perhaps the garden-variety earplug is my best bet. They're a pain to remove and re-insert, though.

 

[Aardvark]

This point has come up a few times here, in various forms, and it was my concern in point #1 in the OP.

That's why online/print reviews by people who use noise-reducing headphones for travel or industry don't really help me, and why I'd thought to try a model designed for noise reduction by means other than cancellation.

Trouble is, I have no idea if -- or how well -- any of the designs work. And you can probably deduce from my job description that I'm not likely to accept a company's marketing claims unless I can verify them independently.

The Etymotics seem designed for listening, and the Sennheiser use noise-cancellation. So perhaps the garden-variety earplug is my best bet. They're a pain to remove and re-insert, though.

The Sennheiser HD 280 pro use a barrier design, not noise cancelling. The shape of the enclosures, leatherette pads and snug head fitting design are what help these cans block external noise by around 25db, that is why my son can use them for drum practice, he can both listen to the piece he needs to accompany and also have the sound external sound level reduced to protect his hearing. Many drummers go deaf over time, I SAID MANY DRUMMERS GO DEAF OVER TIME

 

[jon]

This point has come up a few times here, in various forms, and it was my concern in point #1 in the OP.

That's why online/print reviews by people who use noise-reducing headphones for travel or industry don't really help me, and why I'd thought to try a model designed for noise reduction by means other than cancellation.

Trouble is, I have no idea if -- or how well -- any of the designs work. And you can probably deduce from my job description that I'm not likely to accept a company's marketing claims unless I can verify them independently.

The Etymotics seem designed for listening, and the Sennheiser use noise-cancellation. So perhaps the garden-variety earplug is my best bet. They're a pain to remove and re-insert, though.

To state the obvious, if you want to have noise playing to drown out the sound of conversation etc., an earphone/headphone will be best; if not, you may as well save your money and go for an ear plug. One other option might be to wear earplugs *and* play white noise through headphones on top of the plugs...

All earphones/headphones are, to an extent, made for listening If you're not using them for music, though, why not try something cheap like koss spark plugs - will work like ear plugs to block some external noise, and let you play white noise or whatever to yourself. Or lots of drummers seem to use the sennheiser phones aardvark suggested - so would guess they do a decent job...

 

[Walter Wayne]

The Sennheiser HD 280 pro use a barrier design, not noise cancelling. The shape of the enclosures, leatherette pads and snug head fitting design are what help these cans block external noise by around 25db, that is why my son can use them for drum practice, he can both listen to the piece he needs to accompany and also have the sound external sound level reduced to protect his hearing. Many drummers go deaf over time, I SAID MANY DRUMMERS GO DEAF OVER TIME

We have some barrier type head-sets around the workplace, though since I am not in the manufacturing area I don't know just how good they are. Use for protection when working with the machinery. They don't have speakers or anything, just a barrier (which means they all wireless!!!)

That or what Aardvark is proposing sounds like it would be your best bet for broad band sound reduction. Main worry as someone pointed out may be fire alarms and such. A minor thing may be comfort. I am guessing it gets a little sweaty under them at times.

Walt

 

[Aardvark]

I am guessing it gets a little sweaty under them at times.

Walt

You got that right Walt.

The inner ear jobs dont have that sweaty thing going on, but nevertheless they do cause a feeling of heat build up in the outer ear canal.

My problem is that I learned as a child to wiggle my ears quite markedly. As an adult I tend to do this subconsciously when studying. This is very uncomfortable when you have objects buried in the outer ear canal

 

[Kaylee]

First, cancellation works on stationary sorts of noise, those for which the characteristics don't change much. In other words, about the opposite of key clicks.

Second, cancellation in headphones only works at low frequencies. Due to a whole bunch of issues, once you have about 1/10 of a wavelength between the sensing microphone and the driver that's doing the cancellation, that's about all you can do. (This has to do with stability of the system, changes in the soundfield with distance, etc.)

For a headset with a mike 1" from the headphone driver, that puts you at about 10" wavelength.

1153*12 in/second / 10" = 1300Hz... At best.

Sorry, yes, it would be nice, wouldn't it?

I'm not a techie, but I do wear hearing aids and I can tell you that feedback cancellation at a higher pitch is used in many digital hearing aid brands. Specifically they are used to cancel the high pitched microphone feedback which allows hearing aids to increase amplification in the nearby frequencies. Before that technology was implemented in hearing aids, audiologists had to program in a cookie bite in the amplification around that frequency range to cut down on microphone feedback.

I forgot what the pitch is specifically and googling didn't reveal anything today -- but I think it's around 4000Hz.

Regrettably this info probably isn't going to be helpful to Piggy today, but the technology to cancel higher pitches does exist. If someone knowledgable in engineering wanted to be very agressive and cobble something together, perhaps they could. My understanding is that most hearing aid manufacturers don't manufacture their own components, but buy them from the same few companies.

 

[ktesibios]

Most barrier-type hearing protectors- earplugs and the over-the-ear muffs- produce more attenuation at high frequencies than low. Since the noise of typing on keyboards is weighted towards the high end, ordinary earplugs or earmuffs might turn out to be pretty helpful in reducing the annoyance.

BTW, I was working in the office machine business in the early '80s. Some of our customers, notably the insurance companies, had typing pools- big rooms full of transcriptionists typing away. I had no problem with doing repairs in rooms full of typewriters banging away, but when the customers switched their typing pools over to word processing systems I found the constant "ticka-ticka-ticka" to be infinitely more annoying than plain ol' electric typewriters. Though the sound level was much lower, there was this Chinese water torture aspect to it that drove me right up the palm tree.

 

[Soapy Sam]

I knew a guy who rode a motorbike to work.
Some days he kept the helmet on.

Nobody disturbed him on those days.
In fact people tended to leave as early as possible.
You might try this if you care more about your concentration than your reputation.

 

[jj]

I'm not a techie, but I do wear hearing aids and I can tell you that feedback cancellation at a higher pitch is used in many digital hearing aid brands. Specifically they are used to cancel the high pitched microphone feedback which allows hearing aids to increase amplification in the nearby frequencies. Before that technology was implemented in hearing aids, audiologists had to program in a cookie bite in the amplification around that frequency range to cut down on microphone feedback.

I forgot what the pitch is specifically and googling didn't reveal anything today -- but I think it's around 4000Hz.

This is actually a different thing. Feedback prevention is a subset of echo cancellation, basically, and can work a lot better than noise cancellation. Don't forget, in echo cancellation you know the source of the feedback exactly. In noise cancellation, you have an observation problem in that the soundfield changes with distance in a way that is unpredictable and variable.

 

[jj]

Another thing that does occur to me is that it is true that simple sealing headphones work better at high frequencies. A combination of good sealing headphones and noise cancellation ought to work pretty well, using noise cancellation at low frequencies (where it's hard to cancel) and isolation at higher frequencies.

 

[Piggy]

Looks like an earlier reply of mine never posted. Sometimes I move on from the preview screen before submitting.

ktesibios, I agree w/ you completely re the keyboards v. typewriters! Typewriters are easier (for me) to tune out, like machinery. Keyboards are like the skittering of insects.

Thanks to everyone for the input. I think the best place for me to start is going down to the local New Age bookstore and getting some white noise CDs from the 99-cent bin and playing them thru my current cheap headphones, which I know are comfortable.

If that irritates me, then I'll consider trying some barrier-type headphones with good reviews for comfort.

No problem w/ alarm systems. We have some deaf workers, so our alarms are visual as well as auditory. And my staff already have to alert me on the extremely rare occasions when an intercom announcement applies to me -- my desk is farthest from the ceiling-mounted speaker, so I can never hear what they're saying. And as far as I'm concerned, the fewer phone calls I answer, the better.

My boss would never allow the helmet.

 

[Kaylee]

This is actually a different thing. Feedback prevention is a subset of echo cancellation, basically, and can work a lot better than noise cancellation.

I didn't realize that, but even for a non-techie (me) that makes a lot of sense.

Don't forget, in echo cancellation you know the source of the feedback exactly. In noise cancellation, you have an observation problem in that the soundfield changes with distance in a way that is unpredictable and variable.

Good point.