I'll second evrything John Schroth said, with one addition: if you're 
transferring using a stereo cassette deck, listen in MONO. If you're 
listening via a standard hi-fi receiver, the mono button on it should do 
the job. Adjust while listening in mono, and turn the screw while 
listening for maximum treble. In the ideal case, you should hear no 
difference in the treble content when you switch from mono to stereo and 
vice versa.

This tweak, and the ones John recommends, will get you the best 
transfer. Save that as your archive copy (make a couple of backups on an 
external hard drive and/or a thumb drive). *Then* start messing with 
Rx5. Oh, do the original transfer at a bit depth of 24 bits and a sample 
rate of 44.1kHz -- Rx5 does its stuff best on 24-bit files, and a 
44.1kHz sampling rate lets you make CDs with no sample rate conversions. 
Do all your manipulations at 24 bits; at the very end of the process, 
convert to 16 bits if you're planning to make a CD.

Paul Stamler

On 6/20/2018 6:13 PM, John Schroth wrote:
> Hi Dan:
> Before you start experimenting with audio plugin's, etc, to enhance the 
> audio to make it more intelligible, I'd recommend experimenting with the 
> azimuth adjustment on the playback head of the used micro cassette 
> player you just bought. You'll get a much better end result if you start 
> with a properly adjusted playback head and most of the time, it's well 
> worth the short time it takes.
> Micro cassette players were banged around a lot, most were cheaply made 
> and not well calibrated from the factory. For these reasons there can be 
> quite a difference between the original record head azimuth that laid 
> down the recording on your tape and the playback head azimuth on the 
> used unit you just acquired. The difference between dialing in on that 
> original record head azimuth and not, can sometimes be substantial and 
> you can really open up the higher mid-ranges and treble by making the 
> adjustment.
> Most micro cassette recorders - even the cheep ones, have a small hole 
> through the plastic case near the playback head. When the head is 
> engaged into the tape, you can get to the screw that adjusts the azimuth 
> with a small jewelers type screwdriver - better yet an electronics 
> screwdriver. Make sure the screwdriver is not magnetized. Slowly turn 
> the screw 2 revolutions or so in one direction. If you don't hear a 
> difference, go back to null and try the other way. Don't push down as 
> you make the adjustment, as the screw/head assembly can be on a pressure 
> spring and pressure will effect the azimuth as well. Keep adjusting 
> until you hear the mids/highs open up. Hopefully you'll hear quite a 
> difference between being dialed into the original record head azimuth 
> and not. If you have a hardware phase scope or software phase scope with 
> your capture software, watch the visual representation of the audio as 
> you make the adjustment. The audio pattern on the scope will tighten up 
> as you "come into" azimuth. This in many cases, will make a bigger 
> difference than any digital post processing you can apply later.
> A lot of people are scared to make this adjustment. If you don't plan to 
> record using your micro cassette unit, there's no harm in doing this 
> (unless you turn the screw in too many times and strip it or screw it 
> out from the threads in the base). I don't have a single tape deck in 
> any format here that is properly calibrated for "factory" azimuth 
> because I don't record on tape here - I'm just getting content off tape 
> - which means I'm always changing the azimuth adjustment no-matter the 
> format, to match the original record head. I still kick myself for 
> spending all that money on MRL alignment tapes when I first started out 
> - I've never used a one!
> All this said, be sure to inspect the payback head, make sure it does 
> not have too much wear (most don't) and that the heads and tape path is 
> nice and clean. There will be posters on this list recommending to 
> rehouse the tape in standard sized cassette shells and transfer with a 
> matching standard cassette deck. Even still, azimuth adjustment will be 
> important with either method. I'd try using the player you have first 
> and judge from the results if its worth taking the next step.
> Kind Regards,
> John Schroth

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