Weird situation...

GeertSamuel

GeertSamuel

Member
Jan 29, 2006
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Nieuw-Buinen, The Netherlands
OK...I'm kinda losing it here right now...

I've got a MOTU 1224 (PCI-424) and SM Pro Audio PR8E.
When I run my mics through the SM Pro Audio PR8E there's no sign that it's clipping! But the signal that comes into the MOTU 1224 signals that it's clipping heavily!
Also, when having the gain knob turned to completely 0 (zero!). It still reaches a input signal of -24 when hitting a snare for instance. When I turn the know just to 1 (0 being completely to the left-out and right is 10 full open) it allready starts to register more and more. When I put it up to 2.5 when hitting the snare normally it justs clips on any normal hit.

I kinda lost everything now..don't know what could be wrong or whatever. Since the output of the MOTU 1224 is good, and there is nothing wrong with.
I seriously don't know what to do now..anybody has got any advice?!?!?!.. :cry:
I wish I had an extra pre-amp laying around here to check if it were just the pre's....
 
The SM Pro PR8E's outputs are +4.

I'm not familiar with the MOTU unit, but is it set to -10?
 
Funky Animal said:
OK...I'm kinda losing it here right now...

I've got a MOTU 1224 (PCI-424) and SM Pro Audio PR8E.
When I run my mics through the SM Pro Audio PR8E there's no sign that it's clipping! But the signal that comes into the MOTU 1224 signals that it's clipping heavily!
Also, when having the gain knob turned to completely 0 (zero!). It still reaches a input signal of -24 when hitting a snare for instance. When I turn the know just to 1 (0 being completely to the left-out and right is 10 full open) it allready starts to register more and more. When I put it up to 2.5 when hitting the snare normally it justs clips on any normal hit.

I kinda lost everything now..don't know what could be wrong or whatever. Since the output of the MOTU 1224 is good, and there is nothing wrong with.
I seriously don't know what to do now..anybody has got any advice?!?!?!.. :cry:
I wish I had an extra pre-amp laying around here to check if it were just the pre's....
Click to expand...

Has it all been working fine before, or have you just got either piece of hardware and this is your first time using them like this?
 
motu's gain structure is weird, because you are allowed to adjust the input gain at 3 different locations, and other units do not allow you to adjust the input gain except for at one location

then again, if it worked before, i have no idea what the problem could be now

seems stupid but logical... retrace your steps?
 
That's pretty strange that those options would be missing on yours. Let me make sure I understand your setup. Does the software actually control the 1224? This really is the only thing I can think of that would be the source of your problem. However, you said you've used it with other pres that work fine, right?
 
Deaf Ear said:
That's pretty strange that those options would be missing on yours. Let me make sure I understand your setup. Does the software actually control the 1224? This really is the only thing I can think of that would be the source of your problem. However, you said you've used it with other pres that work fine, right?
Click to expand...

Yeah the 1224 is controlled by that...
Well when I now get to think of that it was BEFORE I installed Mac OS X (10.4.9)
But like I said I dropped everything in CueMix and there seems to be no problem now...is that the wrong way, or not?!
 
Well I would think attenuating the signal digitally before actually writing the file coming in would be a bad thing theoretically. I've looked high and low to find documentation on the 1224 or the PCI 424, and MOTU wants me to pay 20 bucks for it. If I could read it, I might find something. There's also this weird loop thing that can happen as well that I found out. Not sure if it could be related to your problem at all, but still.


Distortion or clipping when Using Cuemix

--------------------------------------------------------------------------------

If you are patching audio through Cuemix, and also playing back audio to the same outputs from another application, the signals will be summed. You won't see any indication of this overload in DP or AudioDesk, because as far as DP is aware, there is no clipping.

The distortion that results from summing the Cuemix output and DP output is actually not clippping, but is actually called "wrapping". Wrapping sounds a little bit different than clipping. The waveform is not getting a flat-top as it would in a clip. It is actually being shifted to the zero crossing at the point it would exceed the digital limit. To avoid this, you'll need to be careful that the sum of the 2 output sources don't exceed 0. When you are working with a source that was already normalized to take advantage of all the bits, you have little room to add another signal. You'll need to scale the master output of DP, and the master output of Cuemix back to achieve the desired balance.

When in doubt, change your Input Monitoring Mode in DP or Audio Desk to Monitor through Effects instead of Direct Hardware Playthrough. Use a Master Fader in the mixing board to monitor the sum of your overall output.

---------------
 
Deaf Ear said:
Well I would think attenuating the signal digitally before actually writing the file coming in would be a bad thing theoretically. I've looked high and low to find documentation on the 1224 or the PCI 424, and MOTU wants me to pay 20 bucks for it. If I could read it, I might find something. There's also this weird loop thing that can happen as well that I found out. Not sure if it could be related to your problem at all, but still.


Distortion or clipping when Using Cuemix

--------------------------------------------------------------------------------

If you are patching audio through Cuemix, and also playing back audio to the same outputs from another application, the signals will be summed. You won't see any indication of this overload in DP or AudioDesk, because as far as DP is aware, there is no clipping.

The distortion that results from summing the Cuemix output and DP output is actually not clippping, but is actually called "wrapping". Wrapping sounds a little bit different than clipping. The waveform is not getting a flat-top as it would in a clip. It is actually being shifted to the zero crossing at the point it would exceed the digital limit. To avoid this, you'll need to be careful that the sum of the 2 output sources don't exceed 0. When you are working with a source that was already normalized to take advantage of all the bits, you have little room to add another signal. You'll need to scale the master output of DP, and the master output of Cuemix back to achieve the desired balance.

When in doubt, change your Input Monitoring Mode in DP or Audio Desk to Monitor through Effects instead of Direct Hardware Playthrough. Use a Master Fader in the mixing board to monitor the sum of your overall output.

---------------
Click to expand...

Yeah after micing up some drums, it's NOT the ideal situation..

I use Cubase NOT DP...so I need to check if there is a way to disable CueMix or something is that what I understand from that?!
I might have to call MOTU for support then...
 
I'd totally call MOTU. I'm sticking to the -10 and +4 scenario. It really is the only thing I can think of that would cause that. Let us know what you find out.
 
Deaf Ear said:
I'd totally call MOTU. I'm sticking to the -10 and +4 scenario. It really is the only thing I can think of that would cause that. Let us know what you find out.
Click to expand...

Yeah, I'm now going out to rent an other pre-amp to cancel the mic pre's out completely..if it also errors those pre-amps...it's the MOTU and I will get back tot them on this!!
 
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