Sponsored by Creative Control Concepts
 | ||||||||
 |
 |
 |
|
 |
|
 |
|
 |
| Home
Automation FAQ Sponsored by Creative Control Concepts |
|
||||||||||||||||||
|
|
 Home Automation FAQ : Speech : Recognition :
Do you have recommendations on the types of microphones to use? |
| [An excellent answer found on comp.home.automation] I'm going to wade in here with some thoughts and explain what is working for me. This is about what works and what is practical given the budget and needs of the average professional that wants the luxury of a reliable home automation voice recognition system. Until a highway accident ended my career in 1991 I had 19 years in designing and building high power commercial radio stations and recording studios. All ego aside, I have not been as involved in industrial communications since I retired but this application is very basic and straight forward. The first point I want to make is that the most common speech input device for VR systems is a telephone. They're not too, sexy but everyone has one and they are easy to interface. I'm not advocating that we use telephones for HA VR. My point is quality of the voice. Telephones have a very narrow bandwidth, optimized for clarity, intelligibility and minimum back round noise. We have exactly the same goals in voice recognition. My point here is that high quality and expensive microphones are not required to build a good VR sound system. We have three thing to consider in choosing microphones for VR. Microphone gain or sensitivity, directional characteristics and frequency response for intelligibility in large spaces are the primary considerations to get your voice command to activate an event. It must be of sufficient gain to pickup your voice from preferred locations and the voice must be easily recognized by the computer over and above room acoustics and background noise. My first suggestion is to ditch the high dollar microphones with superior frequency response because they are going to sound like a telephone before we are finished with the equalizer anyway. My second suggestion is to be practical and not try to build a system that will hear your voice command in every corner of your home. You will be disappointed and frustrated. Even the widely used and much revered Crown PZM microphones specifications require that the voice be within three feet of the receiving microphone to meet published specs. If you normally turn on the entertainment center from your reclining chair, if you normally turn on the porch light from your reclining chair, then perhaps you should have a microphone near your reclining chair. This microphone won't turn on the stereo from the front door but how often do you turn on your stereo from the front door? If you want the dining room lights to dim when you say grace then put a microphone near your dining room chair. When I used to mic. stage plays and productions it never made sense to mic. the whole stage. We always mic'ed. the prop nearest the person speaking his lines. Television is done much the same. What I'm trying to illustrate is to place microphones in precise areas where they are practical. When you demonstrate your system to your friends they do not know nor care that the system must be addressed from strategically placed microphones. As far as they know you are casually speaking into the air and the lights come on. In my bedroom we have a cheap $6.00 desktop computer type microphone on each bedside table. My wife and I can both give a voice command in a normal voice without disturbing the other. This is very important point to comprehend and the most difficult to get across to most people. The expectations of Voice Recognition is pretty high and many times hard to achieve. Use directional microphones to your advantage. I've thrown up a web page with some explanation of directional microphones at: http://members.xoom.com/nlindsey/Microphones/Microphone.html Be realistic when you choose what rooms you want to speak commands from. Unless you have the budget for $3,000 to $5,000 12 channel mixers with gating, individual EQ and compression you are not going to be happy with the time and frustration you'll expend trying to mic. an entire house. It simply isn't practical in a family dwelling. (We can dream though can't we?) Finally, if at all possible choose a line level microphone or place a pre amp at the microphone location and run line level back to your mixer. It leaves open many future options. Just my $.02 worth. | |
 Append to This Answer |
| Next: |
 New Item
|
| ||||||||||