Wednesday, 2 June 2010

Speech Recognition - olympus, mic


For a cheapo microphone, I was pleasantly surpised with how well this worked at picking up speakers who were a distance away. You may have to adjust the sensitivity of the recorder, because the sensitivity of this mic is significantly higher than the built-in stereo mic, and recording to 'hot' will result in garbled, distorted sound.



The Olympus recorders seem to select sensitivity with labels like 'dictate' and 'conference', where 'conference' would normally be used in a distant recording situation but if the record bar hits the right side of the screen you want to set it to the lower sensitivity mode 'dictate'. In any case, with this (mono) mic you should change your recording mode to Mono so you can get double the record time. Olympus ME-52W Noise Canceling Microphone

My first reaction to this microphone was astonishment at is its small size. It's larger than most lapel microphones, but that's because of the physical requirements for noise-cancellation. Still, it's very small, especially for a true "cardioid" (noise-cancelling) microphone.



The performance is superb! As Jim wrote, it is very sensitive. I tested it in a quiet room at distances up to 10 feet away. At about 3 feet, my voice was strong and clear. At 10 feet, it was obviously remote, but the sound was good and very clear, with no echo. Off-axis, the sensitivity drops rapidly. At about 70 degrees, the sound weakens noticeably, and beyond 90 degrees, it is almost inaudible.



M. L. Strickland is correct in warning that the microphone requires external power. The instructions on the box specify 1.5 - 10 volts. Writers who reported that the microphone was very weak were almost certainly using a recorder that does not provide the necessary excitation voltage. This energizer voltage draws negligible power from the recorder's batteries.



However, he is wrong when he writes, '... the noise "cancelation" is only provided by a directional shield. True cancellation is obtained by using a stereo mike with the two pickups wired to cancel noise that arrives at both equally.'



Noise-cancelling microphones have existed almost from the start, long before stereo ever existed. The close-up photo on this page clearly shows a slot ("port") in the side of the microphone's body. There is another on the other side. These ports channel sound to the back of the transducer (the sound-sensitive element) so that it is 180 degrees out of phase with the sound striking the front. These opposing signals cancel each other acoustically, but there is always some sound "leakage" through the case and because of imperfect cancellation, resulting in a weak output.



This microphone is intended for recording sounds at a distance, which is the purpose of all cardioid (unidirectional) microphones. Its output level is higher than on most microphones, so there is a possibility of distortion, especially if the sound source (such as the speaker) is too close. For a normal voice, I suggest it be held 8 to 12 inches from the speaker's mouth.



This microphone was bought to be used on an Olympus DS-330, a six-year-old monophonic digital voice recorder. The internal microphone is sensitive and effective, but because it is omni-directional, recordings in a noisy environment, or at a distance from the speaker, are unclear. The ME-52W mic worked equally well in the "Dictation" (low-sensitivity) and "Conference" (high-sensitivy) modes, but the "Dictation" mode is preferable. It's almost identical in sensitivity to the "Conference" mode, and omits residual background noise, such as radios and air conditioners.



With a rated frequency range of 100 - 15,000 Hz, and depending on your equipment, the ME-52W makes excellent voice recordings, and respectable, but not perfect, music recordings. It essentially eliminates echoes, and strongly reduces background sounds. If it's compatible with your equipment, it should be a winner.

I did an interview in a noisy restaurant and put the recorder on the table with the mic pointed straight up. The mic picked up both voices very well and cut down the background noise by at least 70%. The interview would have been impossible otherwise.

Be careful. This microphone requires power to be applied from your recording device. This is described on the box and in the enclosed spec sheet, but I don't see anything about it on the Amazon site.



Did not work at all with my laptop.



Also the noise "cancelation" is only provided by a directional shield. True cancellation is obtained by using a stereo mike with the two pickups wired to cancel noise that arrives at both equally.

This microphone has been an excellent addition! I use it to record to my Olympus WS-321M digital recorder, and I LOVE it for capturing my dictation or for capturing presentations/lectures that I give. The lapel clip and cord makes for easy and clear recording, while I keep the recorder in my pocket. This is excellent for audio interviews, as it eliminates much of the ambient noise; however, the cable isn't long enough for a video interview with a camcorder (seems long enough for a webcam interview). Also, when I want to capture comments from around the room, I remove this microphone. I just purchased a stereo omni-directional microphone, so I will try that for conference room discussions.



Note: this is a MONO microphone, which means it doesn't work with equipment that requires stereo inputs -- I found this out when trying to use it with my video camcorder and captured no sound (lost one video presentation!). It seems that this is the same problem some people are having with this microphone for their laptops. Also, that means that podcasts/recordings only come out of one headphone/speaker, which can be frustrating for listeners. If you are recording voice



I also downloaded some simple (and free) audio editing software (called FreeAudioDub) that allows me to cut, rename or save clips, delete extraneous filler. - Noise Canceling - Digital Voice Recorder - Olympus - Mic'


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