Tascam 644 backing track dropout while overdubbing

Discussion in 'TASCAM Analog Forum' started by Danielj.la, Mar 27, 2021.

  1. Danielj.la

    Danielj.la New Member

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    Hi all,

    First post here-

    I picked up a TASCAM 644 Midistudio seemingly in well-kept condition.

    I'm pretty new to tape and was hoping to get some advice from people with experience who care about/know about the format.

    The machine has a bit of a learning curve but I've been able to get going okay, though now I've run into my first issue:

    I recorded the main of a track onto Track 1 of the tape, but when doing a vocal overdub (onto track 2), the backing track drops out when I sing a bit louder. It is almost like the radio compression effect that when the announcer speaks the background music dips quite a bit. However, when listening back to the track everything is just fine. I'm just hoping it is something I can work around or fix and not a problem with the machine!

    My immediate guess would be that because my main track has so much on it that adding a vocal so close to it is causing the monitoring warble (?). I'm just using the only tape I had which is normal type I I think from Duplication.ca (60 minutes), so maybe that has something to do with it? These are just hunches as I'm not very familiar with tape.

    Any thoughts would be much appreciated!
  2. Danielj.la

    Danielj.la New Member

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    Little revision: I was mistaken -- when I sing a little bit louder it actually swells the background track suddenly, so it's really distracting if you're trying to sing with the right dynamics.
  3. Freebird

    Freebird Member

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    Hm... sounds weird! I have never had that problem with my 244 which also records on 4 tracks.

    I would suggest that you try to record your vocals on track 3 or 4 instead of track 2. That way the sounds are farther apart on the tape. I know that there CAN be some issues concerning "over-bleed" from track to track since it's actually analogue sound, and that the 4 tracks are close together on a small cassette-tape compared to a wider reel to reel tape.

    But it sounds a bit strange that the backing track should play back louder if you sing louder? I'm not a technician by any means, but maybe there is something wrong with the electronics, some kind of overload or something like that?

    I do know that some people have had problems with their recording/playback heads not being aligned perfectly. Who knows... maybe there is only a screw that has to be tighten somewhere around the tape heads so they stay put? But as said... I'm not a technician... I'm just guessing/brainstorming here... :rolleyes:
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  4. SkywaveTDR

    SkywaveTDR Well-Known Member

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    When I see people demonstrating their use of decks I constantly see the level going full up into the red. These are idiots and do not at all understand recording or the use of tape. Let them try that with digital and all their over the top levels will be truncated. That means cut off and dumped into oblivion where that kind of recording belongs.
    Are you using the Dbx on the deck. Maybe the levels are causing the bias leakage to jump tracks because of higher levels and they do not like to have that jump but it does as the track format is too small. There are limitations on these decks that you have to deal with otherwise you should be using a 1/4 inch 4 track or a 1/2" tape 8 track deck minimum.
    The noise reduction dBx system might be sensing higher level bled over from an adjacent track and being it is a VCA type device it will adjust the decoder gain to what it sees be it bleed through or a crosstalk issue. This kind of deck should never have levels high into the red. (VCA mean Voltage Controlled Amplifier)

    As a Chief Engineer in Radio in Chicago, the term you are wanting to say is ducking but that causes the caller audio or other audio to decrease as the host has priority. I think that was a part of a telephone processing system for call in stations. Telos was the brand we used when Gentner was bought out.
  5. Danielj.la

    Danielj.la New Member

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    Thank you all for your responses.

    I did have everything staged ok as for the levels (under the zero mark for the vocals and the other track leveled correctly as well). DBX has been on the whole time.

    Thanks for the warning about the levels though -- will definitely be careful with this. Ah yes ducking that's right. Well actually I'm not sure I can revise my title but actually the reverse is happening -- when I sing onto track 2 while monitoring this causes the backing track in my monitor to actually swell/get louder, which is distracting and throws me off while trying to track the vocal.

    As suggested I instead put my vocal to track 3 and don't have an issue with that. Perhaps it has something to do with the tape type? Finally getting some proper tapes (II) today.
  6. Danielj.la

    Danielj.la New Member

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    Also, main track (1) has a fair amount of sub bass from this Novation Basstation Synthesizer, as well as a fair amount of instruments. I'm wondering if this plays in --
  7. SkywaveTDR

    SkywaveTDR Well-Known Member

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    Track 1 and track 4 or 8 depending on how many you have are always trouble as they are on the edge of the tape and cassette tape does wear- if you look at the fresh tape the edges seem to be looking up but on a worn tape they show to be curling down.
    Meters don't always show levels accurately depending on frequency. Sub bass or low frequencies can cause more problem as they are more prone to bleed over which is why the tests are done with 100Hz on other equipment. If main instruments are recorded on a track, I would start with track 2 as I leave track 1 and track 4 or 8 for last. Bass and non- critical sources should be recorded on edge tracks as these have more drop out than the other track.

    Also when testing a deck for problems all noise reduction is turned off- we never do calibration with it one as much of it does frequency skewing.
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  8. Danielj.la

    Danielj.la New Member

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    This is great information, thank you.

    This may belong to a new thread, but from what I'm reading the type II's don't respond with the same desirable 'tape' effects as type I's when the level is hot. When you say this deck should never have red levels, are you referring strictly to when recording using type II's? From what I understand, running type I's won't do anything to damage the machine (I could be wrong about this).

    I think I also read that the low end isn't quite the same on type II's, in which case I'm wondering if it wouldn't worth pushing low end/mid rhythm and bass hot onto a type I...

    For reference, I'm working within the dance/house music arena, drum machines, synth basses, pads mostly. Pretty new to this but I really enjoy the punch of tape.

    Any thoughts/advice would be much appreciated, pretty new to the medium!

    [I hope you don't mind that I edited this for you]
    Last edited by a moderator: Mar 30, 2021
  9. SkywaveTDR

    SkywaveTDR Well-Known Member

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    No worries, I used to deal with Board Op at Moody and ESPN and Spanish Broadcasting where I was chief Engineer that I asked them who told you to run levels far in the red- the idiots at Columbia college of course. I told the board op that there is a Orban Optimod down the hall that takes all your red levels out before it goes to the STL. We didn't pay $14,000 for them to be running level in the Red for that to take it out. Now if they clip the signal it can't do anything with that but the PR&E boards we had never clipped that I ever saw. Still it contines to be hard to get through to some people.
  10. SkywaveTDR

    SkywaveTDR Well-Known Member

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    Porta Studios- I think all of them were all made to work with Chrome tape TDK and Maxell not BASF types only. No Ferric tape should be used in the machine as then you are purposely overbias that tape which leads to distortion and rolled off high end. I test the deck I work on with Maxell XL II C-90 tape that is all. People that use the wrong tape in a machine there is just no hope for them and I can not fix their problems. The Best Chrome tape made was TDK HXS.
    It is a weakened Metal tape. Low end music is best produced on larger format tape as cross talk can be excessive with low end audio. Regardless of what type of dBx the level needs to be watched as this does not give license to record at high levels. There is a lot of nonsense type use of these machines now days more than in the past.