Speech privacy (peach piracy) exists when a conversation can not be understood even if it can be heard.

There are 4 levels of speech privacy; normal, confidential, inaudibility and none.

• Normal speech privacy exists when someone can only partially understand the telephone conversation or the meeting in an adjacent office cubical without having to stop, listen and concentrate on the conversation.

• Confidential speech privacy exists when you can only hear mumbling coming from the other side of the office partition. If you can occasionally make out a word, but you cannot understand the context or intent of the conversation then the conversation is confidential.

• Inaudibility exists when you have no idea that a person is speaking in the adjacent room.

• There is no speech privacy if you can actively participate, without trying, in the conversation being held in the adjacent work station or office.

So why is there always one individual on a floor or building who complains they do not have enough privacy even though their colleagues seem to be fine? This person thinks that speech from an adjacent office space (open plan or private) is obtrusive and annoying. What they are experiencing is a "signal to noise" ratio problem. The solution is to reduce the ratio for greater speech privacy.

The higher the signal (speech, phone ring, etc.) over the noise (partition sound reduction plus background noise) the more intrusive the sound will be. This ratio of signal to noise varies throughout a floor or building because the building system noise, traffic noise, HVAC system noise, and office equipment noise all vary throughout the floor. It would be similar to having different areas of the floor illuminated with 25 watt bulbs, 50 watt bulbs and 100 watt bulbs. Some individuals will feel that the lighting is too bright in their area while others will feel that it is too dark.

Another important factor is that the quality or type of noise has an impact on its obtrusiveness. Individuals on speaker phones or people with naturally loud or boisterous voices can be particularly irritating.

A particularly boisterous worker could be quieted by a muzzle. But, while this may be an effective and inexpensive solution, it is not really practical. Another solution is to increase the perceived sound isolation between work spaces as we discussed in our Spring '93 issue on office acoustics. Improving the walls, office partition heights, and increasing background sound levels to a uniform level throughout the office space (sound masking) all significantly improve the perceived sound isolation within offices and speech is generally not as obtrusive.

Next Issue: Sound Masking -- How Does That Work?