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Conference napalm::commusic_v1

Title:* * Computer Music, MIDI, and Related Topics * *
Notice:Conference has been write-locked. Use new version.
Moderator:DYPSS1::SCHAFER
Created:Thu Feb 20 1986
Last Modified:Mon Aug 29 1994
Last Successful Update:Fri Jun 06 1997
Number of topics:2852
Total number of notes:33157

1005.0. "Yamaha DX7 - Some Patches "Wobble" - Why?" by MARVIN::MACHIN () Fri Nov 06 1987 06:11

    I have a DX7 I that's developed an annoying feature.
    
    Voices such as leadlines, flutes, guitars and the like
    occasionally develop a slight vibrato, the speed of which 
    seems to have nothing to do with any lfo settings. If you press
    a key harder (activating the aftertouch) the voice returns to 
    normal, straight pitch. I can also fix the problem by moving
    the data entry slider.  
    
    This happens even when all mods are switched off. It's slight,
    but annoying. 
                           
    Anybody know what's going on?
    
    Richard.
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1005.1USS won't fix this wobble...JAWS::COTEBIM me up, Scotty!!!Fri Nov 06 1987 08:248
    My TX81Z has a similar problem. I use the Mirage as a master keyboard.
    If I send use the MOD wheel to modulate the LFO on the TZ, it continues
    to wobble slightly after returning the wheel to 0. It eventually
    stops. It also stops if I nudge the wheel up a hair.
    
    Weird, no?
    
    Edd
1005.2AKOV75::EATONDShut mah mouth wide open!Fri Nov 06 1987 08:407
	It wouldn't happen to be a problem of detuning operators - beating, 
would it?

	Not that I know much of anything about FM...  Just a thought.

	Dan

1005.3Ping Ping boyng ARGGGGHHHHHMARVIN::MACHINFri Nov 06 1987 09:378
    It happens on all voices, but it's more noticeable on sine-type
    patches. 
    
    Analogue synths are a different kettle of fish, but this sort
    of thing's a bit odd in a digital circuit, isn't it? It suggests
    a number's drifting into a hole where a zero should be.
    
    Richard.
1005.4Doesn't sound like a digital error to meDSSDEV::HALLGRIMSSONEirikur, Compound Document Prod. Mgr.Fri Nov 06 1987 10:505
    Sounds more like an analog problem to me.  Could you both be having
    flaky aftertouch-sensor problems?
    
    	Eirikur
    
1005.5No such thing as an electrical failure.MAY20::BAILEYSteph BaileyFri Nov 06 1987 13:518
    I agree with Eirikur.  I have never had such a problem.  How old
    is your machine?  (In keystrokes, please.)
    
    I would suggest opening the sucker up (it must be out of warantee
    by now...) and checking for loose cables and suchlike.
                                      
    Steph
    
1005.6E!xorcised wobble?MARVIN::MACHINMon Nov 09 1987 08:027
    No loose cables or unsecured chippery to be seen.
    
    Besides, the problem's too close to Edd Cotes' TX symptoms to be
    a one-off. I bet Steph Bailey has a latent wobble in there somewhere,
    just waiting to pop out. Unless the E! board cures it...
    
    Richard.
1005.7DETUNE !!!NYMPH::ZACHWIEJAEvil games for evil mindsMon Nov 09 1987 12:0019
    If you make use of the DETUNE parameter this is expected behavior.

    This happens when you have two sine waves of the same course  and
    fine frequency but one is DETUNED.  The waves will start  out  in
    synch,  but will slowly pull themselves out as the sound develops.
    This becomes more exaggerated as  you  add  additional  operators
    that are DETUNED.  All the waves start together, will drift apart,
    and at sometime in the future will  resynch.  Unfortunately,  the
    period between synchronization can be quite long as it  is  equal
    to the LCF (least common frequency) of all the operators or waves
    involved.  Usually this period is much longer than  any  envelope
    you have constructed for your carriers.
    
    Pressing a key  again  or  using  aftertouch  should  synchronize
    the waves again,  but only when you have KEY SYNCH on.
    
    As for the data entry slider.  Beats the hell out of me.
    
    Zach.
1005.8I knew it must be a feature..MARVIN::MACHINMon Nov 09 1987 12:077
    Great! Sounds believable to me. I suppose using the mod wheel would
    also resynchronise things. And if the data entry slider was left
    'live' on some obscure parameter....I'll check. 
    
    Thanks.
    
    Richard.
1005.9E!? For TX7s?DYO780::SCHAFERResist.Mon Nov 09 1987 13:416
RE: E!

   Sorry to digress, but did Grey Matter ever make an E! board for a
   *T* X7? 

8^) who_has_never_noticed_wobble_on_his_TX7s
1005.10Must get to the bottom of this wobbleMARVIN::MACHINTue Nov 10 1987 04:3611
    Right -- I tried everything, and it's the LFO that's to blame.
    Changing the speed, wave, amplitude or pulse mod parameters affects
    the type and degree of wobble.
    
    If you have a TX or DX, I'd appreciate your trying it. Select
    a clean, lead-type voice. Play and hold a note, and flick the
    mod wheel in and out. Sooner or later, the dreaded wobble will
    strike. Or not. It's not down to detuning, since the same thing
    happens with a single, un-modified tone.
    
    Whoever heard of a harpsichord that wobbled? Not Bach, I'll wager.
1005.11undocumented test routines (argh)MARVIN::MACHINTue Nov 10 1987 09:489
    
    Just rang Yam service. They told me to hold down the function
    key press 16 and 32 press yes until I see A/D select mod wheel move
    the mod wheel until I don't get 0 open it up spray it with switch
    cleaner do it again if no good send it in. Phew.
    
    This may take some time...
    
    Richard.
1005.12Wait a minute.MAY20::BAILEYSteph BaileyTue Nov 10 1987 13:5132
    With proper punctuation and phrasing, that test procedure is:
    
    1) Using the <FUNCTION> button as a shift key, press patch select
         button #16.
    
    2) Using the <FUNCTION> button as a shift key, press patch select
         button #32.
    
    3) Press the <YES> (data entry +1) button repeatedly until
         ``A/D SELECT MOD WHEEL nnn''  appears in the display.
    
    4) Move the modulation wheel until nnn is non-zero.
    
    5) Go nuts with the pot cleaner at that point.
    
    6) Repeat steps 4 and 5 until there are no more points where nnn
          is non-zero.
    
    
    Is this correct?  I can't wait to try this tonight, but I suspect
    that E! removed whatever diagnostic features used to be implemented.
    
    
    Re: E! for TX7.  No.  The E! upgrade for the DX7  basically gives
    you a heap of new performance/keyboard oriented features, plus a
    few other random things, so it wouldn't really do much for a TX7.
    
    What other performance features would you want on a TX7?
    
    Steph
    
    
1005.13Poly-timbrality. 8-(DYO780::SCHAFERResist.Tue Nov 10 1987 16:460
1005.14Great test -- shame it tells you nothingMARVIN::MACHINWed Nov 11 1987 04:0214
    re .-2
    
    Yes -- that's right. Except you press 16 and 32 while holding down
    function (bit like rebooting an ibm pc).
    
    You can run through a whole bunch of tests this way, except mine
    passed all with flying colours and still wobbles. Also, all
    documentation -- and the engineer on the phone -- said that A-D
    values should begin at zero. Mine begin at 1. Oh -- and the touch
    response sticks at 2 -- but that's not the source of the wobble.
    
    Back to the tin whistle for me.
    
    Richard.
1005.15DX diswobbledHEART::MACHINThu Dec 03 1987 07:489
    For those who have the wobble, and are ashamed to admit it:
    
    it can be fixed. Mine is. 
    
    And just a quick plug (of interest to Southern Brits only, I'm
    afraid) for Andertons in Guildford who were quick and informed.
    (And they have a good stock of gear, too).
    
    Richard.
1005.16Who fixed it ?NYMPH::ZACHWIEJAOne step from sanity.Thu Dec 03 1987 12:376
    
    Are you saying that the chaps from Andertons fixed it for you,  or
    are you saying that they gave you more info concerning diagnostics
    and the like,  allowing you to fix it yourself.
    
    Zach
1005.17Yamaha fixed itHEART::MACHINFri Dec 04 1987 04:336
    They sent it to the Yamaha service centre here. The service people
    phoned me about it, and answered questions I had about the midi
    implementation. They also turned the repair round, door to door,
    in two weeks.
    
    Richard.