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Trouble with "Active Sensing" Midi event


doc
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.... I think I'm better in that electronic stuff than in the midi thing ... :-[

My Sid step C is ready an works *fine* when connected via midi to my PC. I can play tones by pressing keys in midi-Ox. So far so good...

When I'm connecting a keyboard to my SID station I get a kind of high  squezzzy constant  sounds until I press a key on the keyboard.  The note will sound and when I release the key I get that squeezy sound again.

When I connect the Keyboard to the midi-ox PC I get constand messages from the keyboard. The midi-OX "Monitor-Input" Window tells a lot of messages like this:

0003A5C8   3  --     FE    --    --   --  ---  Active Sensing

(fills the screen after a while). I also get the note on/off events when I press a key. But then the Active sensing messages come again and again.

Now my (dummy) questions:

1.) Can anybody tell me, if this "active Sensing" messages are causing my "squezing" problems and

2.) if so: what can I do, to stop them. Can I change the SID software, so that it will ignore those messages ?

Help ! ??? please ! someone !

Thank you

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That active sensing is just a message from your keyboard to say: "Hi I´m still here"

It´s just used to let the computer (or anything else) know, that the keyboard is still there. If it´s deconnected, the comp (or what the hell) knows, somethings wrong. Thats all for active sensing.

Because of that I´m pretty sure, it shouldn´t be the reason for those tones. Perhaps it´s a bad MIDI Out of that keyboard. To go sure, use a MIDI Interface (e.g. keyboard at MIDI In A and SID at MIDI Out B or however).

TK? Active Sensing making weird sounds??

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Thank you for your prompt answer !!

I tested it with two different keyboards. (Both from YAMAHA if this matters). It doesn't work.

I don't know where this tones came from. The only difference to play the sid by midi-ox is the "active sensing" massage. This message doesn't appear, if you play the sid with the pc-keyboard. Thats why I thought it is this message causing my problem.

I connected the keyboard exactly right. From midi-out of the keyboard to the midi in of the SID. I even tested various midi-cables. This can't be the reason.

**confused**

When I connect the keyboard to  my midi-cv converter of my MSS2000 (yes I have two of them !!) everything works fine.

*** still confused ***

???

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*Also a proud MSS2000 - owner / builder * (check the latest Midibox of the week - on the third pic you can see it in the background of the SID). Handshake!!  ;D

(Dammit this baby is making cool bass sounds if you connect it correctly).

I didn´t mean the connection from the keyboard to the SID, I meant connecting the keyboard first to a MIDI Interface (like the USB device of UCApps or some MIDISport from MIDIMAN or whatever) and connecting the SID to that MIDI Interface, too. Then using Cubase or whatever to play the SID that way.

If both Yamahas are causing the same prob, it should be the active sensing mesage. You can´t filter that out so easily. The only thing I can recommend is the MIDI Interface thing from above. This way the active sensing messages are filtered out. Perhaps TK can bring some light into this one.

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Hey. I read it already so I know you have a MSS. I builded the first one three years ago. I also "modernized" several original Formant modules and the elektor Vocoder. Damned great synth !  ::)

Back to my damned problem. I try another device. Give you a replay in 10 minutes.

Till then...

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The vocoder is worth to build even it's a little outdated. But it makes funny sounds when singin' through it. I use the vocoder for special sounds taken from a microphone, routed through the Vocoder and then plugged into the "External Envelope Follower" of the MSS. Sounds great ! :-*

I only had the original elector articles for it to build. I took 2 x 3 HE 19" modul cases because I didn't get the original case. I made no backplane because you can get the plugs for the modules but no backplane that fits. So I made a little adapter pcb for every module. The pcb has two connectors. One for the module pcb and the other has a plug "50-pol Pfostenwanne" (don't know in english), just like the MSS connectors (20-pol) but with 50 pins. I connected all modules with a flat cable in parallel as a backplane. The caps from the original backplane I soldered on my adapter pcb's. The rest is almost original. If you don't make adapters you have to change a lot of pcb designs ! (that isn't worse it). If you're interested I can give you detailed information. But be warned: I'm a quick planless solderer. I don't document the projects very well  8)

Back to my problem.

I  took your advice and connected my good old midi box beetween the SID and the keyboard. Now it works (almost). I don't get the randows squeeze sound anymore. But sometimes a note hangs. And (more complicated) sometimes a various slave SID stops working. When I press Link off and on it will work again.

The midi in and midi out LED of the midibox are continious flashing (I think because of the "Active sensing" messages).

Can you explain me, why it is working with a midi device between it ?  ???

Doc

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Cool, I will think about that vocoder (I already have all schematics, so no need to send me anything).  :D

Having to less time!!!  ;D

For that new problem: That could be some grounding or power supply problem (try to use shielded cables for connecting the slaves to the master MIDI Out - worked out well for me and rather use TK´s PSU recylce - works great!).

Why it does not make sqeezing sounds: There is nearly *NO* Midi device that forwards active sensing messages (makes absolutely no sense) - could be reason one. And (more like it) the MIDI In / Out schematic of the MB64 is a high quality one - many companies try to save money there - TK doesn´t.

For that active sensing stuff, let´s wait for TK´s answers...

TK??  ;D

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Thank you moebius,

I also was thinking of grounding problems.

Now I connected TKs Midi-merger between the yamaha and the SID. Even this works great.

It really seems to be a poor midi-signal from my yamahas. If it would be a ground loop, it should stay when I connect the Midibox or the Merger beetween the devices, shouldn't it ?

After using grounded wires between the cores, my second problem (missing sids) is gone ! Thanks Pay_c again  :-*

Still waiting for the 'masters'  (TK) comment on the "Active sensing" stuff mentioned before.

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It really seems to be a poor midi-signal from my yamahas. If it would be a ground loop, it should stay when I connect the Midibox or the Merger beetween the devices, shouldn't it ?

I was thinking that something is sneaking from yamahas past your optoisolator. Midi input should be completely isolated from signals driving it. Is your MIDI input jack in contact with grounded MB case? Or middle pin grounded?

Bye, Moebius

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Hi,

i´ve got exactly the same problem (squeezing note). I´m also using a Yamaha keyboard (SY77), which is sending Active Sensing. I´ve got some old Ensoniq keyboard, but it´s in the basement of my parents, 600 kms away, so I can´t test with this synth right now. If Active Sensing is the problem, it should occur with almost any synth connected as I haven´t seen a synth without active sensing yet. A.S. is a very unnecessary thing IMHO, it just makes LEDs on bigger interface boxes flicker and takes up bandwith...

I´ve found no solution yet, except routing MIDI through MIDI-OX, which doesn´t help me very much because I mostly play keyboards in a band. So there´s no computer at the rehearsal room or on stage.

I just checked the grounding issue. Grounding the middle pin to c64 PSU 5V negative line or to security ground of the wall outlet doesn´t help.

Another problem: Every time my fridge starts or stops humming, the SID doesn´t output notes anymore until I change the patch up and down again. Possibly coming from bad power source in the house, but how can I avoid this? On stage, power supply mostly isn´t good and clean either (because of the light dimmers etc.).

Any help is appreciated :)

Seppoman

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Yikes!

What I mean that ground shouldn't be connected, and maybe even DIN connectors body shouldn't be in contact with input devices ground point. Opto is doing all the work here. (Sometimes ground loops arise even when devices are connected to grounded power supplies and to another device with another ground connection.. Like synths -> mixer)

Bye, Moebius

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This strange noise is caused by a ground loop, just ensure that neither the shield of MIDI In, nor the MIDI Out is connected to ground (although the ground connection can be seen in the core schematic, for synthesizers with Audio Outputs like for the MBSID it's better to remove it)

Note Hangs: sometimes happens when using the PIC16F, thats a known problem and cannot be solved. The PIC16F is not powerfull enough to handle every MIDI event in realtime when the SID software engine is under full load (too much features). Solution: use a PIC18F

MIDIbox crashes when fridge (or soldering iron...) starts to work: EMC problem, a metal case could help.

Best Regards, Thorsten.

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Hi,

But isn´t a ground loop normally a 50hz hum? This sound also is not always present but after some notes have been played there´s either a hanging note or this squeak (which sounds a bit like an extremely high note hanging). Both can be stopped sometimes by playing a lot of notes at the same time.

I also tested this with Midi-Out N/C and DIN Plug away from the case.

And I´ve got 18F version, so this is not the cause either.

Seppoman

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You guys are mixing totally different issues here...

Seppoman: I guess that the reason for your problem is the exotic display you are using (see also the german board).

To check if this is the reason, just set "CS_ENABLED" to 0 --- this will also deactivate the display. Better: disconnect the display from the core (but use the original MIOS release, since your display driver has no timeout mechanism!)

If the SID is working ok thereafter, you know that the extremely slow display and the high power consumption is the reason.

Best Regards, Thorsten.

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Hi Thorsten,

I see you´re also doing a night shift today :)

the display can´t be the reason: I bought a cheap 2x16 hd44780 for testing before I got the VFD and this effect also occurs with standard MIOS/SID version. And with VFD connected it also only occurs when the Yamaha keyboard is directly connected to the SID. With the computer inbetween, everything is ok.

Thanks for the timeout hint, I´ll check that tomorrow (and also will answer your other msg - I´ve got to get up again in 3 hours ;) )

Seppoman

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Hey .... are you never sleeping ??? :o

Thank you again for all your replays. Let me try to answer all that stuff:

To moebius:

I'm almost sure now, that it isn't the active sensing message. Don't know if its a ground loop, because there is no metal for the case (C64 plastic). There is no Ground pin connected to the MBCORE. There is just one cable connected from the synth to the core. Still strange, but now I connect the midi-merger between it. This works for me (till I know something better ?!?).

To seppoman:

I have a good Idea for your fridge problem:

Use a line noise filter before your AC-Adapter like this:

IN --------L1--------L2------- OUT

  |      

            C1

   |                

IN --------L3--------L4-------- OUT

C1 = 470n/250V

L1...L4 = 100µH/5A (e.g. Reichelt No.: FED 100µ)

This little circuit kills all that hum from dimmers, relais, fridge etc (under 50 Hz).

You can use one circuit for more devices because it handles a current of max, 5 A (about 1000W)

Shall I give the important notice about high-voltage ? - So be careful !!

If somebody tells me, how to load pictures in this forum, I give you a better image of the circuit  8)

To TK:

Special thanks to the 'Masters-voice'.

I check the ground thing again. At the moment no notes hang. So its hard to test this again. It seems the the TK midi-merger kills all that unwanted stuff. With the merger it works. Still don't know why. But: Never change a running system (exept: I find out why its not working when connecting a Synth direct to the cores) :-[

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Doc:

Thanks for your suggestion :) . Is there a way to do power filtering also in the DC domain? I don´t even like external power supplys, so I would rather not be carrying around another box.

Another filtering issue I have: When the VFD display Thorsten mentioned is connected to power I get a faint hum on the 6581 SID (not on the 8580 slave). This also occurs when the display is not connected to the core, so I think it can´t be a grounding issue either but the display injects ripple to the 5V cirquit. I thought perhaps a very low low pass filter in the 5V line could help this, but don´t have enough electronics experience to tell if this could help (and what type of filter should be used). Do you have any suggestion about that?

TK:

No, normally the keyboard doesn´t send CCs (and isn´t gm/xg compatible either). But I just noticed another strange thing: When connected to the keyboard, all WT sounds are extremely slowed down when I send aftertouch or turn the mod wheel. Routed through the computer this doesn´t happen (and as far as I can tell the Midi-Thru from MIDI-OX doesn´t filter anything, so except the Active Sensing or perhaps some electrical issue the SID should receive the same informations).

Seppoman

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Hi Thorsten,

the note hang/squeak problem is also there with the standard MIOS/SID/LCD.

I tested the slowdown thing again, I found "slowdown" only occurs (both with normal setup and VFD) when e.g. the ARPSEQ sounds are played by the slave. Sounds somewhat like the Mod wheel had become a sample scrub wheel... On the Master SID interestingly the Mod wheel turns down the volume quite smoothly when the kb is connected (also in both configs) - although MCC is set to 0 !?

Perhaps when playing on both SIDs with a lot of CCs the VFD could cause some timing problems (not tested yet), but I´m absolutely certain that the problems with directly connected keyboard have nothing to do with the display (as I said everything tested in normal config). Also when playing single note lines with a bit of mod wheel, I didn´t find noticeable latency yet.

Seppoman

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