Warning: I am very new into learning about sound production and/or restoration so I apologize in advance for any misused terms or naive questions!
I am attempting to digitize A LOT of wildlife monitoring data kept on cassette tapes - maybe like ~ 1400 cassette tapes. I am trying to avoid sending them out somewhere, from what I gather a good restoration service is ~$500 per 40 tapes. I'd like to do it myself. My original plan was to get a bunch of the cheap amazon handheld converters and run multiple at once but from what I've read there's a huge difference between a cassette deck \ converter set up and the cheaper handheld devices. The recordings are ecological soundscapes of frogs and insects. I'm interested in the low-frequency animals within these recordings (below 10 kHz). The cassettes were well packaged in a cool and dry place.
What are the most important things that I need to consider? If my main goal is not to capture absolutely perfect and clear audio, like one would do to restore music, but I want to restore audio "good enough" to preserve signals, and their corresponding frequency range in order to make accurate species ID....Some of these animals sound exactly the same but occur at different frequencies! Does anyone have any equipment, specs, or venders that they'd recommend for digitization that aligns with this goal, that is attainable to start in the next few months, and that is hopefully below ~$500? I see Pyle decks are reasonably priced, but I have also read reviews that the new decks aren't as reliable for audio quality.