fld@mhtsa.UUCP (10/11/83)
I originally asked the following of net.audio and net.video: > I have two tape recorders. One is better than the other. (assume they are > the same format). > > When I need to copy a tape, will I get a better copy by playing the > original on the worse machine (and recording on the better), or by > playing the original on the better (and recording on the worse)? > > Is there any general answer, or is it very specific to each machine? > > I think that I have had better results when recording with the worse > machine, but .... I will give my own interpretation of the responses, and then include some excerpts from the mail I received. If you responded to me, and feel that your view is misrepresented, maybe I didn't receive the mail, or maybe I didn't agree - this is my opportunity to respond. In fact, I think I have only eliminated redundancy and obvious superstition. Anyway, the conclusions: 1) Maximize positive situations, such as: - tapes generally play back better on the machines on which they were made (except maybe the Nakamichi Dragon audio cassette?). - Use a machine with proper bias/eq settings for the brand of tape you are using. Also make sure that the deck has the proper noise reduction circuitry (Dolby B/C, DBX, etc.). 2) Cheaper machines can generally record better than they playback because a quality playback head must have a narrower head gap than a record head (which must be wider to avoid saturation). (This applies certainly to audio, but not video, right?). When an audio deck makes one head serve for both recording AND playback, the head is generally optimized for recording, not playback (e.g., a wider head gap). So, there is no general solution, but, all other things being equal, use the better deck for playback, and the worse deck for recording. For total assurance, try both ways and you will learn the truth for your particular two decks. By the way, I expected to get some comments concerning machine electronics, but got none. I expected someone to say something like "use tube electronics for playback to soften clipping," or "playback amplification causes much more distortion than generating the right signal for recording." I do not know enough electronics to judge. (Perhaps you noticed from my above comments). I hope this all is reasonably accurate (this is democracy, right?), and useful to someone. Sorry it is so long. Excerpts follow. - Fred Dalrymple, BTL MH. These statements are not necessarily endorsed by my employer. ==================== I suggest that you try to match as closely as possible the decks to the tape (ie, if your play tape was not recorded w/ dolby, it probably won't help to play it on the deck that has dolby; likewise, if only one deck has adjustable eq and bias and your record tape is better quality, then play it on that deck) I guess what I'm trying to say is match the best tape with the best deck for the best result. ===== (Ed., A net.video response:) You didn't state in your query whether or not the 'better' deck had two or four heads. If it has four, you're better off recording on that one, as the recording is made with a head more optimized to record at that speed*. It's a reasonable assumption that the 'cheap' deck has only two heads, and those are a compromise design to enable 2, 4, or 6 hour recording. *The four heads are designed so that one pair is used for 4 and 6 hour recordings, the other pair for 2 hour (or equivalent speeds in Beta). ===== High quality playback depends very much on the head. A narrow gap is required for good high frequency playback response. Yet, a wide gap is important for recording, to avoid saturation problems in the head. (This is why 3 head open-reel decks have a distinct advantage.) The end result is that manufacturers of cheap machines often use a fairly wide gap. (They use the same head for record and playback.) This kills the highs on playback yet often lets the machine make usable recordings. So if you can, and want to be bothered, try recording some tones from a sinewave generator, then try to copy the tape using both hook-ups. Now you can look at the results on a level meter (and even a distortion meter) to see which approach works better. Or, trust your ears - especially if you are the end user of the copy. ===== Since the "badness" or "goodness" of a tape deck is a measurement of the quality of record and playback "in series," so to speak, there is no _a _priori solution to your problem. You have to test it both ways. The only hard-and-fast rule about copying tapes is that they almost always sound better if you dub them backward: that is, having both playback and record tapes running the wrong way. With a half-track or full-track tape deck, this is easily accomplished by turning the tape over and running it the other direction. With quarter-track and cassette formats, this gets a little hairier. (I'll admit that I'm too lazy to figure out a way to get cassettes to go backward and I no longer use a quarter-track open reel machine.) ===== If your cheaper recorder is one with only two heads (a combined record-playback head and an erase head) and your better deck has separate heads for record and playback, then your decision is clear-cut: play the tape on your good deck and make the copy on the cheap one. The reason is that playback requires a finer head gap than recording to reproduce the higher frequencies. When one head must do both, it is optimized for recording, not playback. If both decks are three-head, you probably are still better off making the recording on the cheaper deck, though the difference may not be as great. It is easier (and cheaper) to produce a good record head than a good playback head. ===== [ Ed., another from net.video: ] When making a dub, experiment with different audio levels. Most VCR's have a limiter in their audio recording circuit that makes setting the correct audio level tricky.