Hi!

I've got a nice little break out box called a Midiman Omni i/O, that houses a Delta 66 card. I was wondering if someone might please be able to help me figure out something about the clip LED light associated with each of its two preamps?

I always thought a red light on these signal clip LEDs was warning me that the signal going in Mic/Instr. Channels 1 or 2 preamps was at (or close to) the 0 dbFS on the Delta 66 card.

But looking at page 16 of the Omni i/O manual ( www.m-audio.com/images/global/manuals/Omni_i-O_Manual.pdf ), I see that these LEDs are UPSTREAM of the Delta 66 card (also, downstream of the preamp).

What then does a red light on the signal clip LED mean ... that I'm applying too much voltage for the preamp itself to handle, so IT is distorting? Or, is it somehow calibrated so that IF it were passed through to the Delta 66 card it would cause digital overload (I'm not sure if that's the right term, I mean it would cause >= 0 dbFS)? Or ...

My specific situation is that I am using an insert point to route to a compressor, and that insert point is UPSTREAM of the Delta 66 card (and downstream of the signal clip LEDs). So, will the red light be meaningful under those circumstances, or should I just make sure my digital signal peaks flowing from the compressor to the Delta card are where I want them, while ignoring the red light?

Thanks for any help!

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Alexis -Cubase 6.5.0/SX3.1.1.944, XP SP2, 4GB RAM (1GB not accessible, but used just to balance the computer so it doesn't tip over); Delta 66 in Omni i/O Studio; Motif8; UAD-1

Hi alexis,

The Omni has four analogue signal clip indicators:

Two are associated with the preamps, to help you set a suitable position for each of the rotary gain controls.

The other two monitor the output level of the Omni mixer, with 'clip' indicating a level of 2dB below clipping. As you say, these clip LEDs are prior to the send/return sockets, so I suspect it will monitor the level going to your compressor input.

As long as you set any input gain control on the compressor to a suitable value, you can still rely on the Omni clip indicators to show the the compressor is close to being clipped.


Martin

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YewTreeMagic

Hello Martin -

Thank you so much for your answer!

Can I follow up with two more questions in the newbie way please?

Quote:

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Martin wrote: "... Two are associated with the preamps, to help you set a suitable position for each of the rotary gain controls."

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So, Martin - if the red light goes off here, that means it's purely an analogue problem? ... relating only to exceeding the voltage capacity of the preamp?

If so ... what is the best way to figure out what position to put the trim knob at? The Omni i/O has other inputs besides through the preamps (the aux ins, FX returns, e.g.), I guess all these sum to the final signal that is monitored by the output signal clip LEDs?

Quote:

---

Martin wrote: "... The other two monitor the output level of the Omni mixer, with 'clip' indicating a level of 2dB below clipping. As you say, these clip LEDs are prior to the send/return sockets, so I suspect it will monitor the level going to your compressor input."

---

Martin, by any chance could this be backwards? Looking at the flow diagram on page 16, I think the output level LEDs of the Omni Mixer are well downstream of the insert point to the compressor? ... and it's the preamp LEDs that are upstream of the compressor input point?

Last question for clarification please, Martin: When you say it "indicates a level 2 dB below clipping" - does that mean 2dB below Full Scale?

Thanks, Martin!

--------------------
Alexis -Cubase 6.5.0/SX3.1.1.944, XP SP2, 4GB RAM (1GB not accessible, but used just to balance the computer so it doesn't tip over); Delta 66 in Omni i/O Studio; Motif8; UAD-1

Quote alexis:

---

Hello Martin -

Thank you so much for your answer!

Can I follow up with two more questions in the newbie way please?

Quote:

---

Martin wrote: "... Two are associated with the preamps, to help you set a suitable position for each of the rotary gain controls."

---

So, Martin - if the red light goes off here, that means it's purely an analogue problem? ... relating only to exceeding the voltage capacity of the preamp?

---

Yes - they are measuring the analogue levels at some stage of the preamp.

Quote:

---

If so ... what is the best way to figure out what position to put the trim knob at? The Omni i/O has other inputs besides through the preamps (the aux ins, FX returns, e.g.), I guess all these sum to the final signal that is monitored by the output signal clip LEDs?

---

If you're talking about the preamp clip indicators then you should simply lower the gain controls slightly whenever you see them lit, as this shows you are perilously close to clipping.

Quote:

---

Martin wrote: "... The other two monitor the output level of the Omni mixer, with 'clip' indicating a level of 2dB below clipping. As you say, these clip LEDs are prior to the send/return sockets, so I suspect it will monitor the level going to your compressor input."

Martin, by any chance could this be backwards? Looking at the flow diagram on page 16, I think the output level LEDs of the Omni Mixer are well downstream of the insert point to the compressor? ... and it's the preamp LEDs that are upstream of the compressor input point?

---

Just had another look at the Omni manual, and page 17 shows the two final output level LEDs are immediately prior to the Record/Monitor/Headphone outputs, and therefore after the insert return, while the preamp LED are just before the Insert send, so you hsould be able to use the first two as send level indicators and the final two as return level indicators.

Quote:

---

Last question for clarification please, Martin: When you say it "indicates a level 2 dB below clipping" - does that mean 2dB below Full Scale?

Thanks, Martin!

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Hmmm... It's not immediately clear whether any of the four 'clip' indicators are in the analogue or digital signal path (i.e. before or after the converters).

2dB below analogue clipping is not wise, and is likely to sound harsh, so I'm hoping it's 2dB below digital clipping and that the analogue path still has some headroom at this point, in which case you're right that it would be -2dBFS.


Martin

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YewTreeMagic

Martin - Thank you so much for taking the time to answer this, including looking at a page 17 of the manual of some 10-year old piece of equipment ... it's stuff like that that makes SOS and it's writers Da BOMB!

**Goes off to play, feeling more confident of what his signal path is ...**

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Alexis -Cubase 6.5.0/SX3.1.1.944, XP SP2, 4GB RAM (1GB not accessible, but used just to balance the computer so it doesn't tip over); Delta 66 in Omni i/O Studio; Motif8; UAD-1

My pleasure alexis - glad my advice helped


Martin

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YewTreeMagic

I had one of those Omni I/Os and I just used to set the gain using the level meter on my DAW. I found on my unit that the DAW input meter hit 0dB long before the clip light on the input channel came on.