Excellent Expensive Microphones for Voice Dictation
by Birger Petterson Update June 2005
- Platforms Tested Upon: IBM ThinkPads 770-1AU,770X-7AU,and 770Z-8AU.
- Software Tested Upon: IBM ViaVoice Executive Version 5.2.
You may have the best voice dictation program. Unless input is essentially perfect, the voice dictation engine cannot perform to its maximum accuracy potential.
The larger the vocabulary and the more commands and macros you have, the harder it is for the speech engine to parse combinations of contextual clues to decide what you are trying to say. Everyone has a slightly different voice that must be taken into account. We dictate in different environments.
There are many microphones out there for voice dictation. Some are better than others. Some only work well with high speed processors, 300MHz and above. Others work well for discrete voice programs but will not work for continuous voice dictation programs. Some have a bumpy frequency response curve or range of frequency response. As vocabularies of voice dictation programs increase, it is important to feed audio to your voice engine properly.
Four years ago I purchased a Heil Pro-Set headphone and microphone with the HC-5 Key. This microphone has a frequency response 350 Hz - 4000 Hz with a 6 db rise at 2100 Hz. This microphone is for ham radio and SSB suppressed carrier operation. This set has great sound on the head-set, very comfortable, and performed well on IBM VoiceType 1.2 a discrete dictation program. With the release of Dragon's first continuous dictation software, on a 33 processor machine, this microphone could not perform adequately. On a 233MHz processor machine it shows some progress. On a 300MHz processor machine , the Heil Pro-Set microphone works well. However, it uses more than twice the kernel usage of the Sennheiser MD 431.
My criteria is that the microphones I test and report on must perform starting with the 486\100 up to and including Pentium 366. Note; the 486\100 is discrete dictation. All the others cover both discrete and continuous voice dictation.
For overall performance in a noisy environment the Sennheiser MD 431 gives superb performance. In fact the voice file made during enrollment using this microphone is about the purest that you can get. This voice file can be used subsequently with almost any microphone. I use this microphone mounted on a microphone stand and a microphone boom. Some people mount on a desk stand, others are happy holding the microphone. You only need to be 2 to 8 in. away from the microphone to get excellent Recognition.
Another handheld microphone I like is the Sennheiser ME 65 with a K6 power module. This microphone is very sensitive and with a windscreen can be used in a moderately noisy environment. You only need to be approximately 10 to 14 in. away from the microphone to get excellent Recognition . This microphone can be boom mounted, desk set mounted, or hand held.
The K6 power module used in the above can be used with a Lavalier microphone like the Sennheiser MKE-2-60. This superb microphone when attached to your shirt collar makes you more mobile. However you are still attached by a microphone wire. This microphone when used with the supplied metal windscreen performs quite well in a moderately quiet environment.