You don't mean both sides. You record on the same side its that you mean both directions. There is only oxide on one side of the tape. Newer tapes have a back coating to reduce print thru and reduce tape slippage thus lowering wow and flutter and increase timing accuracy for the full length of the tape. While listening to a pre-recorded tape change your mode selector from stereo to mono. The highs should remain if they deminish or the sound becomes garbled you have head alignment issues with the play head. If the sound is similar with plenty of highs and clarity you are OK. While recording if you switch to the mono mode and the highs collapse then you have record head alignment issues. If in the stereo mode the high frequencies are to dominant or sound slightly depressed then the tape machine wasn't calibrated for the tape you chose to record on. Once your tape machine has been calibrated to a particular tape family , you can't switch unless you have your machine recalibrated.. I gave up on tape many years ago, I dubbed my tapes to CD to get around tape deteriorization and all the compatibility issues. Back in the day if you were using Scotch 200 series or Ampex Grand master or Maxell or TDK high output low noise tapes, you had to pick one and stick with it. You could switch between 406 to 407 or 456 to 457 from Ampex but you couldn't go from 406 to 456. Same goes for the different versions of Scotch or Maxell. Consumers tried to, and did often enough but then they wondered why the sound wasn't quite right. Its just like changing phono cartridges. All sound different, with some being pretty close to the RIAA standard and some really different. I agree these issues could be challenging. One reason everyone hoped by. switching to Digital all these challenges could be conquered. We'll we know now they weren't. As the engineers and producers had their own ideas what. the original sound was supposed to be and tried to correct the original sound and failing miserably some of the time when remastering original analog recordings... Then there are the engineers and producers that are trying to create the new sound of the day to entice listeners to their performances. The sound doesn't have to recreate the sound accurately but make sound that captures the audience, using their earphones plugged into phones or iPods. The sound being produced when played back on great systems that were designed to produce authentic recordings accurately are totally different than what is thought to be popular by listeners using ear plugs and phones. Reminds me of the days when sSony came out with the Walkman.
