Help Digitizing Cassettes (Phase Reveresed)

Discussion in 'Tape Recorders' started by westy, Mar 19, 2008.

  1. Kev

    Kev Well-Known Member

    Joined:
    Nov 13, 2001
    the roll of the eyes wasn't because hip hop didn't require proper treatment for archiving
    BUT
    it is very likely that MS was NOT the chosen method of recording

    if it were acoustic or classical or even some jazz then an MS was very possible

    a POP or heavy metal record would also be very unlikely for an MS thang

    if one is serious about archival then a spec'd up cassette deck is a must
    I have even been known to use a spare cassette deck and deliberately trim it to suit the cassette tape presented
    IF the tape was made on a deck that was out of alignment then a correct trim is not what you need

    this is just guess work and you trim to get the best sound you can
    mostly looking for a good smooth top end and hope the low end stays in tact

    once the left and right are in the DAW you can bump and trim one side for a tight centre and then hope the stereo spread still holds true

    hope that makes sense
    sometimes you just have to use any trick you can

    if more cassette archive work is in your future then a couple Audio Cassette Alignment Test Tapes will be useful
     
  2. JoeH

    JoeH Well-Known Member

    Joined:
    Jun 22, 2004
    Location:
    Philadelphia, PA/ Greenville, DE
    Home Page:
    I think we've come full circle in this discussion, and have established a few important things now:

    1. The Tape deck has balanced In/Out connectors. These are XLR, not TRS, so using of a pair of XLR cables to the RME interface/breakout fantail you show is indeed do-able, downright recommended.

    2. The "Phase" problem is most likely inverted material on one channel vs. the other. So, assuming the azimuth is "in the ballpark", things should be ok, at least to get you started.

    3. You'll get better results working with professional (+4) levels with the XLR i/o's than you would with the RCA (-10) connections.

    Sooooo......you can either fix this problem on the fly - as you transfer - with ONE of the connectors in ONE of your XLR cables phase-reversed,

    OR

    You can fix it after the fact, by recording each channel as Mono tracks, and reversing the phase digitally, with your software. BOOM! then you're done that part of the process, and then can get down to the biz of TRULY cleaning up and restoring the tapes.

    If you have any problems with the terminology, take a moment, crack a book, or go to Wikipedia and look 'em up. You should be conversant with these terms and understand them if you're going to do a proper job with these allegedy important tapes. (ESPECIALLY if you're helping to save someone's legacy!)

    You should learn and understand these concepts to do the best job possible for this project:

    Balanced vs. Unbalanced (and their related connectors: TRS, XLR, Pin (RCA) and so on.
    Professional (elevated) +4 levels vs. consumer -10 levels.
    Tape Path Cleaning & Demagetization.
    Tape & Head Repro Alignment. (Azimuth, Zenith and Wrap)
    Cassette Deck anamolies and pitfalls.

    After you've got it all sorted out, you may find the tape is still in it's own world, alignment wise, and you may STILL have to tweak the azimuth a bit to get the best overall high frequency playback (and stereo alignment.) (Welcome to the fuzzy old world of analog tape tech service!) You can never assume the deck used to make the tapes was ever aligned or set up properly. The catch-phrase for cassette alignment standards was: "This IS NO STANDARD." Every deck I ever worked with - including the Tascam series - was FUBAR, alignment wise. You just hoped for the best, but expect the worst.

    But that's another topic, for another thread.

    I applaud your efforts to learn and DIY, but if these tapes are as important as you say, you may be better off taking them to a professional transfer facility, and having them do it for you - perhaps even while you watch or observe.

    Good luck with the project, and have fun, regardless.
     
  3. Kev

    Kev Well-Known Member

    Joined:
    Nov 13, 2001
    excellent post Joe

    I'll get out of the way now cos I think Joe covered all of it in a balanced way
    :) pun intended

    I'd forgotten about the " Tape Path Cleaning & Demagetization "
    just goes to show how long it's been since my brain was in tape mode.
     
  4. westy

    westy Guest

    big thanks to basilbowman, kev & Joe, excellent advice
    i have demagged and cleaned the deck in preparation. i also purchased the RME Breakout & xlr leads with a phase reverse adapter from thoman yesterday, so they should be here soon. I want to do this myself as sending 20 + cassettes to get professionally done will cost alot and i feel i can achieve the same results with the equipment i own (with a little help) I will adjust the azimuth screw on the head to get best alignment possible, and have purchased one of those test tapes in preparation. I heard listening in mono would be best, what would I be listening for to know im finally near the correct azimuth? less hiss & snare portions perhaps?

    Question : can one achieve professional (+4) levels with vinyl also?

    Also does anyone have some good tips for cleanup and compression to really enhance them, what would be the best programme to use? I am pretty skilled with cool edit and have recently got wavearts and iZotope RX which i still need to master, but if anyone has correct settings or suggestions i would be very grateful and again thank you this is a wonderful forum with great members :D :D
     
  5. Kev

    Kev Well-Known Member

    Joined:
    Nov 13, 2001
    vinyl ??

    you have a similar issue with some vinyl recording that you want to archive ?

    you will need a quality record player
    good in tact needle and an RIAA EQ amp

    in short this just means a normal record player but with the addition of an amplifier to bring the needle levels up to line level

    there are some pro units that give balanced at +4dBu

    there are some USB computer sound devices that offer the record player input

    otherwise there are some dedicated record play input RIAA EQ amp with balanced +4dBu output

    not sure what would be appropriate for you and your budget

    as for clean up
    generally I would not do any mods for the first archive
    but
    if you want some post clean-up versions then that's fine
    IF you get better software and skills you can always revisit the original archive (digitised)
     
  6. westy

    westy Guest

    ^^ thanks for that kev, Ive no problem with the vinyls phase, just wondering would XLR give me better results as opposed to RCA, I have a good Turntable and phono premap but its just got RCA in and out on both ends. do turntables come with XLR Outs? or would i just use regular RCA out from turntable into a phono pre-amp with XLR outs and that would give me professional +4dBu output? as for the cleanup process I would never touch the original files and always duplicate to cleanup and burn to cd, i have them hiss free etc but haven't been really able to give them compression to achieve that professional sound.
     
  7. JoeH

    JoeH Well-Known Member

    Joined:
    Jun 22, 2004
    Location:
    Philadelphia, PA/ Greenville, DE
    Home Page:
    Good job on getting the RME, Westy.

    But let's take care of one thing at a time, ok? ;-) Get your chops going with the cassette transfer, and see where you stand. You're going to learn a lot and have fun in the process.

    As for the vinyl; a couple of things for when you DO get into it, although KEV has pretty much nailed it for you.

    The general rule for vinyl transfer is this: if the material is commerically available elsewhere - CD remaster, etc., then it's not worth wasting your time doing on your own. If, on the other hand, you have some real need to transfer someone's private, old, or out of print vinyl collection of non-public stuf, then sure, go for it.

    It's rare, though, that people ever archive their material on vinyl alone; most would at least have a reel to reel master somewhere, or even a cassette. Still, if vinyl is all you have, then you've got some work to do, as KEV has already pointed out.

    From what you're asking, I suspect you still don't quite get it regarding RCA outs vs. XLR. That's not the point here. Yes, chances are you'll see RCA outputs coming from the turntable (the signal coming off a phono cartride is in microvolts, VERY Low level stuff - it has to go to a preamp first, with proper EQ). You'll also see a green "Ground" wire. You'll need to connect this to your phono preamp chassis.

    If you're serious about vinyl transfer someday, then you'll need a professional Phono Preamp. In addition to the RCA inputs and ground wire lug nut, it will have balanced level outputs, perhaps a pin block, or an XLR, or even 1/4" inch TRS outs. (Although it DOES sound like you could get by with what you already have, if it's quiet enough, and you can get enough signal out of it. )

    It also SHOULD have various EQ settings for various RAIA curves, from 78 RPM to 33 1/3 to 45 RPM. (Yes, there were different EQ curves for different types of vinyl recordings, depending on their use.) You can of course try to dial this in after the fact, there are some software programs that will give you these curves, or you can reproduce them from a little research on the web and Wikipedia.

    Kev also mentioned proper needles - to do it right, you'll need a different stylus for 78 than you would for 33 1/3, and so on. It's not something to be taken lightly, if you're going to do it properly. (This is a whole nother thread: Conical needles vs. truncated, etc. etc.)

    Once you've picked your turntable, cartridge, needles and preamps, set your levels properly and made the transfers, then you'll work on tick and pop removal, overall cleanup, etc. in the digital domain. (Personally, I would NEVER do any after the fact compression or limiting, unless it was to fix some kind of specific problem.)

    Remember that vinyl recordings were mastered by expert engineers who were working in that field specifically, and the main reason vinyl recordings sound the way they do is because they were made to fit into the sonic & physical constraints of the media. Taking the recording out of that domain - by using the vinyl copy vs. a further-back tape copy, etc., you are working with a flawed, later-generation medium. It can sound OK, even great, in the right hands, with a good copy to work from, but remember what you're dealing with, and don't try to re-engineer it, should you get that far. It will NEVER sound as good as the original master tape.

    Again, I'd stick with your cassette project first and see what happens. Who knows? You may find a niche career here.....
     
  8. westy

    westy Guest

    Once again Thanks Guys.
    These vinyls are all 45rpm mainly 90s stuff good quality. they contain exclusive instrumentals and B-sides that were never or will never be released on cd so they're a must for me to transfer.

    I have a Hagerman Bugle phono preamp with RCA IN/OUTS and a Technics SL1210MK5 TT with RCA Outs. this is a good marriage and the sound quality is excellent with ORTOFON cartridge etc. In terms of buying a professional phono preamp I would love one but couldn't afford the price tag. So

    Question: could I use my Tascam cassette deck to act as an Amp and connect my phono pre to its RCA input and use the XLR outs into my soundcard, giving me professional (+4) levels? and I could adjust the gain?

    I will definitely stick with my cassette project for the moment and Im dying to get my teeth into it, I feel I am capable of achieving good results with the the equipment ive acquired and the knowledge ive learned from this thread in particular. But while I have the thread open I just thought id ask some advice on my vinyl collection that ive been putting on the long finger since forever. Thanks Men
     
  9. westy

    westy Guest

    sorry to bring this thread up but I am just in the process of ripping that particular out of phase cassette. I am using balanced outputs into balanced inputs of My ADC with only one cable phase reversed, when summed to mono its a huge difference but it still seems to lack volume on one channel
    here's a photo of the wave form as you can see one of the channels is smaller

    I stupidly only bought one phase inverter on my order from thoman, do you think using another one will increase the volume in the other channel?
    any help welcome thanks guys
     
  10. basilbowman

    basilbowman Guest

    Which channel is the one that's quieter, the one that's coming in reversed or the one that's coming in straight?
     
  11. Boswell

    Boswell Moderator Distinguished Member

    Joined:
    Apr 19, 2006
    Location:
    UK
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    You only need to phase-reverse one channel. If you phase-reversed both, you would be back where you started (at least audibly).

    Either the cassette deck used for the recording or your replay deck deck is not correctly calibrated. I would simply bring the level up on your weaker channel during post-processing.
     
  12. basilbowman

    basilbowman Guest

    Grab some headphones, and bring up the level of the lower one until the sound is exactly in the middle of your forehead. Listen for the bass, that's often in the dead centre, and the kick, and the lead vocals are almost always going to be dead centre.
     
  13. Kapt.Krunch

    Kapt.Krunch Well-Known Member

    Joined:
    Nov 21, 2005
    To the bold question....No. Another inverter will put them both back into out of phase, just reversed from the original. And then you'll be right back where you started, only poorer and with more stuff gunking things up in the path.

    If you remove the device with the inverter, and record that song again without having ever touched any level controls on anything, are the levels equal, or are they still different? Is it the intermediate device in that one channel? Is it a level adjustment in your computer input? Is the tape itself recorded imbalanced? Is the TASCAM outputting one side lower than the other, for some reason? We don't know.

    Personally, I would have just done an easy flip in a software program, saved some money, and called it done, if it worked. Any time you add a device into the signal chain, there is a chance of detrimental results. There's also a chance for mischief with messing with a digitally-recorded signal, but I would have tried first.

    Is it possible to try the BIAS and level procedures mentioned in the manual, to make sure the tape is playing back properly? Is there extra tape without signal on any of those tapes that you could use? Are all the tapes the same brand and type?

    BTW, if you will be doing any software noise reduction (or any other processing, however minor), and all the songs on a particular tape sound like they were "finished" about the same, you may want to just get everything set properly, record the entire side(s) of each tape, and apply any processing to the whole thing at once. You may want the tape hiss between tunes to sample to tell a program what noise to remove, depending on what program you will use for noise removal, if any. Then you can separate and trim the songs. IF the songs sound pretty much finished and uniform, this will save time and make it more likely that all the tunes have been processed alike, which may help keep everything more the same.

    You may have to process each different tape separately, though.

    Just some stuff to chew on :wink:

    Hope some of it is helpful.

    Kapt.Krunch
     
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