The normal setting is for people who don't want to have to mix down to a stereo cassette deck. I have this very same tascam portastudio and have done it numerous times until I started recording digitally. When you play back a tape that hasn't been mixed down (thats still in high speed mode) it sounds sped up, hence high speed mode. If you don't believe me then email me(eddiecurbside@gmail.com) your mailing address and i'll mail you a tape thats been recorded in high speed mode that hasn't been mixed down yet and hear it for your self.
The rest of what you said is all accurate though.
I'm afraid you're still confused. Here are some direct quotes from a Tascam 424 MKIII manual:
Two tape speeds offer HIGH for greater fidelity, and NORMAL for compatibility with standard cassette tapes.
Note that this means you can play standard cassettes on the portastudio---not that you can play cassettes that were recorded on the portastudio on standard tape decks. This next paragraph elaborates on this.
Tapes recorded on stereo cassette recorders can play back properly on the 424 MKIII if you set the track playback, tape speed, and noise reduction type correctly. Tracks 1 and 2 roughly follow the standard "stereo" format, but tracks 3 and 4 use the "Side B" (reverse side) tracks. So you must turn off Track 3-4 playback to avoid hearing the flip side playing backwards.
For the same reasons, tapes recorded on the Portastudio 424 MKIII will not play back properly on stereo cassette recorders. Material recorded on the 424 MKIII must be mixed down to stereo for final distribution.
Note that it doesn't say "unless they're recorded at normal speed."
It doesn't matter whether you have the 4-track set to high speed or not; you still can not play that master tape on a standard cassette deck and have it play properly. If you do, the material on TRK 1 will appear hard left, and the material on TRK 2 will appear hard right. If you've recorded something on TRK 3 or 4, that will play backwards.
And you're wrong about this statement:
"When you play back a tape that hasn't been mixed down (thats still in high speed mode) it sounds sped up, hence high speed mode."
That's incorrect. If you record something on high speed mode on a 4-track, and then you take that tape out and put it in a standard deck, it's not going to sound high speed like chipmunks. It's going to sound
half speed. It's going to sound like slow motion. Think about it. The standard tape deck is playing the tape back at a slower speed than what you recorded at. It's the same as just adjusting the pitch control wheel on the portastudio to a slower setting, but at a much more drastic rate. I think the pitch wheel (and I'm talking about the wheel---not the high/normal speed switch) will normally only let you speed up or slow down by 12 or 15%. The standard tape deck is playing back at a full 100% slower than the portastudio when set to high speed.
I don't mean to go on and on here, but I'm afraid you're not giving correct information. Either that, or you're just really not saying what you mean to say very clearly. I've worked with cassette portastudios for .... oh I don't know ... over 20 years, and I've had first-hand experience with all of this.
The bottom line to all of this is simple: In order for material recorded on the 4-track to sound right on a standard deck, you need to mix it down to a standard deck. There are two main functions of the HIGH/NORMAL speed setting on the 4-track:
1) The HIGH speed will have a higher fidelity. NORMAL speed can be used if you're not terribly worried about quality and you need twice the tape running time. It has nothing to do with whether or not you want to mix down! You ALWAYS have to mix down if you want the song to play properly in a standard deck!
Ok, there is one exception to that last statement I suppose: if you had the 4-track set to NORMAL speed when you recorded, you've only recorded on TRKs 1 and 2, you've panned them hard left and hard right, respectively, and you haven't used any EQ or effects. IF all of those are true, then you should be able to take the master tape out and play it in a standard deck and hear pretty much the same thing. But that is rarely the case.
2) If you have a normal cassette (i.e., a cassette of Michael Jackson's greatest hits let's say), you can play that tape in the 4-track if you do the following:
Set the speed to NORMAL
Mute TRKs 3 and 4
Pan TRKs 1 and 2 hard left and hard right, respectively.
That's all there is to it.