# Is this possible?

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#### cityslick

##### New Member
First of all, I know absolutely nothing about designing electronic components. That said, I have an audio project in mind that seems possible, but might be cost prohibitive? I'm posting this question here because I don't really know where to start. So, here goes...

I am starting to record my own wildlife sounds and I want to build a portable audio player that will play 16 bit 44.1khz (CD quality) sound files stored on compact flash memory. I've learned through research, that in order to accurately reproduce specific wildlife sounds, I need to achieve a very high signal to noise ratio (>96). Along with that, the player should be capable of an approximate (112 decibels) Dynamic range. A broad frequency range of 20hz to 20khz+ is also desirable. The d/a converted sound should be amplified before exiting via Standard 1/4" mono phone plug to a 15w, 8ohms loud horn speaker (280hz-12.5khz 112db spl).

This is where it gets interesting...

The player will be operated remotely, using some form of RF transmission. A basic telephone style keypad will be used to select the track# for play, pause, stop, and volume control, etc. Individual audio files should repeat until stopped/switching files. Ideal remote range would be 200-300yards.

Remember, nothing fancy beyond the simple basics. No lcd needed, or special title lists or any other unnecessary clutter.

The main unit should be powered by a low dc source (8AA array 9.6?) and have a one button power on/off. The remote should be powered by one 9v or combination of AAs, with a single power on/off.

All electronics must be durable and sustainable to 0 degrees F. (for field use).

Any feedback would be greatly appreciated. Or maybe I'm in the wrong place altogether? Were should I go next?

Thanks in advance!

Cityslick :lol:

#### Johnson777717

##### New Member
Wow! That's quite an Idea. Hunting?

This project can quickly become complicated thinking at a micro level. Macro level thinking, the project is a combination of a few circuits.

There are two key components in this concept, and the entire concept will end up revolving around the decisions made for these two key components. The components are amplification and the transmitter used to control the audio. The princilples are also dependant upon your confidence and knowledge with building electronic circuits.

I look at the concept like this:
1. Audio platform --The audio player.
A. Is the flash memory played by a flash player?
B. Can you burn the audio to a CD? If so, you may be able to use a portable CD player as your platform.

2. Amplification--
A. How much amplification will you need, according to the built in dB level of the audio platform? I assume CD players play max volume around 100dB's? I could be incorrect. Based on that assumption, you'll only need about 20+dB amplification. There are tons of low cost ($10-$20) circuits that will fit the bill.
B. How much noise are you willing to accept? Probably not much, based upon the 16bit 44.1khz sound quality. You may need a filter circuit to clean up the audio after the amplification. This can be added later if you so chose.
C. The more amplification, the more battery usage. General assumption, you'll need a seperate 9V for each amplifier stage.
D. How much are you willing to spend on amplification? Not much, okay, you're going to have to live with some backround noise.

3. Transmitter and receiver package--
A. 200 - 300 yards is pretty far for a simple transmitter circuit. You may be getting into pretty complex and expensive circuits in order to effectively transmit for this range.
B. What kind of transmiting medium are you looking for? Infared? FM? AM? Ultrasonic? Laser? I'd have to say Infared and ultrsonic are out of the question, based upon the 300 yard range. Laser gets expensive, so AM and FM are the choices I suppose.
C. I'm not in tune with transmitters and receivers. I do know that you're looking at a fairly robust transmitter (due to the range), not some \$10 transmitter. Also, I do know that you're looking at a fairly robust receiver because the receiver will be used to control the functions that you need, volume, track play, etc.

#### cityslick

##### New Member
Wow! Thank you for your comments - I wasn't really expecting a response. My overall concern is to maintain simplicity all the way through. (and yes, it's for hunting) I had envisioned a common power source, basic flash reader/processer/d/a-converter/amp----->output. The RF thing would be cool too, but it may have to wait. I'm sure all of this stuff could be assembled into a fairly small circuit. But like I said, I don't really know anything about electronics...

CDs are not an option - too cumbersome,fragile,moving parts. etc. I just can't imagine it being that hard (or expensive) to extract uncompressed audio from flash.

You're probably right about the amplification. That was really the least of my worries. I just don't know how to go from a--->b--->c---?

Thanks.

I'll check with the other source you mentioned.

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