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sailmike
Apprentice
USA
63 Posts |
 Posted - Oct 17 2012 : 05:14:12 AM
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Hi, my name is Mike and I'm hearing impaired, so my knowledge of audio stuff is mediocre at best. I have this class group project in my senior design class at California State University, Northridge that calls for an AM/FM receiver. Some of the specifications are, inputs to include CD, phono, tape, TV, VCR, etc., switchable long range detection, and equalization of the middle three octaves for the audio.
I don't know what switchable long range detection is. Can anyone explain for me please?
Also, I'm not clear on how the equalization part is to work. I don't know enough about audio. Are the middle three octaves low range (or bass), mid-range, and high range (or treble)? Should I go with a low pass filter, bandpass filter, and high pass filter or three bandpass filters? Should the output of this equilizer be combined with all frequencies from 20 to 20k hertz? Or should all the sound come from the equilizer alone?
Sorry for so many questions, but I don't know what will sound best. Also, I don't know what the bandwidth should be to get the best sound.
I appreciate any help you audio pros can give me,
Mike |
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audioguru
Nobel Prize Winner
Canada
4218 Posts |
Posted - Oct 18 2012 : 8:01:49 PM
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Most AM/FM receivers have automatic-gain-control so that they work perfectly with weak, medium stength or very strong signals so I don't know why you are asked to make yours have switched long range detection. So simply make the amount of RF gain switched.
The middle 3 octaves are all mid-range, probably 300 to 600Hz, 600Hz to 1.2kHz and 1.2kHz to 2.4kHz. They should all be bandpass filters.
The equalizer passes all frequencies from 20Hz to 20kHz but boosts or cuts the 3 octaves of equalization. |
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sailmike
Apprentice
USA
63 Posts |
Posted - Oct 20 2012 : 10:58:07 PM
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Thank you for your input. Switched long range detection is one of the requirements for this senior design project.
Ok, to be sure I understand, the pre-amp passes all the frequencies from 20 to 20k Hz plus boosts or cuts the middle 3 and then combines them all before sending to speakers. We are to have 2 speakers, left and right, and balance the two. I'm not sure how all that is to come together.
Thank you,
Mike |
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AM/FM Receiver (Class project)
