Mackie Onyx - Help with setup !

[philboy]

I'm presentely reorganizing my new home-studio that now includes a Mackie Onyx 1220 mixer. I'm sending my synths and a CD player into the Mixer and use the ALT 3/4 buss to send it to my soundcard in order to record them.

I have carefully set up the input gain so that the signal going in the Mackie is very hot.

The problem i have is that anything i send through the ALT 3/4 bus resluts in a loss ot 15 db of gain in my computer, son a signal of 0 db at the output of the Mackie results on a signal of -15 in my DAW. I have a Delta 1010 soundcard. So i started troubleshooting. I thought it might be the cable, so i tried verious others without succes (note that i use nutrik high-quality balanced TRS cables). I even tried unbalanced cables to see, no change. Then i took the Alt 3/4 out and re-routed it back in a free Mackie stereo input and using the "mute" button, toggeled between the direct sound (stereo buss) and the sound routed to aLT 3/4, same thing... loss of 15 db.

I tried to compensate this loss by switching my soundcard input from "+4" to "-10" but doing so, it gets louder but a lot noisier as well.

The manual states the Alt 3/4 output is balanced/unbalanced but nothing indicates a gain change. Anyone noticed?

I really don't see what i'm doing wrong... Maybe i got a bad unit?



Thanks for any input!

Regards,

Phil

 

[DonF]

... a signal of 0 db at the output of the Mackie results on a signal of -15 in my DAW.

This may surprise you, but that's actually just about what you should want, with the remaining headroom on the Mackie nearly matching the headroom in your DAW. Don't confuse 0dBm (zero on the Mackie) with 0dBFS (zero on the DAW). It would be foolish to try to make the two line up.

It's kind of like saying, "The outside temperature is 34 degrees." Is that cold or hot? Depends on what comes after the word "degrees," right? dBm and dBFS are different scales, just like Fahrenheit and Celsius.

Hope this helps,
Don

 

[philboy]

Hey Don, thanks for your input. Ok the levels don't match from the Mackie to the DAW but the problem is that it's pretty much audible. Any signal going direct to my DAW (without going throug the Mackie) has a good signal but what is coming from the mixer 3-4 is much, much quieter. It makes no sense. And as mentionned, if i take the alt 3-4 signal and send it back in the Mackie (bypassing the DAW) i still loose 15 DB... on the mackie meters. Something must be wrong...

I really don't get it , it's pretty much a basic setup...
Other ideas?

Phil

 

[Treeline]

Did you hit the "Mute / Alt 3-4" switch? That mutes the mains and routes the signal through alt 3-4.

 

[orksnork]

what Don is saying is that he doesn't feel you really have a problem...

-15 in the DAW gives you proper input level and good headroom to work with in the mix....the other signals you are routing in might just in fact be too hot....

the more you can cram into your DAW before it peaks out...does not mean the better...

try lowering the volume of everything else, and just turning up your monitors and watching your monitor outs for level....

that's a huge mistake i made when i was younger

 

[philboy]

I just thought it was simply logical that a +4dBu signal sent to a separate buss would end up +4 at the other end of the cable.

Thanks for your help.

Other inputs ?

 

[DonF]

... if i take the alt 3-4 signal and send it back in the Mackie (bypassing the DAW) i still loose 15 DB... on the mackie meters.

What inputs are you routing the signal to, and how are you measuring the loss? (I downloaded and read the manual, so I can answer in more specifics now.)

 

[orksnork]

hmm ill leave it to don then...i'm sure he's gonna be more of a help

 

[philboy]

Hi Don, thanks for your help...

Here's exactly how the signal is routed in my setup:

CD Player (or any other source) to Mackie line inputs 5-6 (Gain to 0 db). Fader set to 0 dB. For my troubleshooting tests i play a CD in loop with a song with very hot and compressed signal, so that the meter remains around 0 dB. Then i press the "mute" button on that channel so that the signal is now routed to the Alt 3/4 output, as if i would want to record the CD in my DAW. Then i take balanced cables (1/4 TRS) from the Alt 3/4 and no matter where i send the signal to, the result is -15 dB , either in my DAW (on Cubase meters) or directly routed back in the Mackie inputs 11-12 (On the Mackie meters) - trim pot and fader set to 0 dB as well.

Pretty simple actually. The manual states the Alt 3/4 is rated +4 dBu, so there should not be signal loss...

Also, i should mention that even without visual metering, anyone would notice because the difference in volume is quite significant.

Thanks to anyone help me understand this!!!

Kind regards

Phil

 

[DonF]

The manual does give the same "mixer rated output" for the main, CR, aux, and alt outputs. But it's a bit vague about the gain staging.

One thing I find curious is that the maximum gain from input to output is vastly different between the main (TRS) and alt outputs -- about 15 - 16 dB different. Part of that is explained by the fact that the main output has a fader (with up to 10dB of gain available), and the alt output does not have a fader. But with the main fader at unity gain, I don't see any reason why you should see a level change when switching between the main and alt outputs. I am puzzled.

 

[philboy]

Hi Don,

I'm puzzled too.

I spoke with the Mackie support, they sent me this link:

http://www.soundonsound.com/sos/may00/articles/digital.htm

It actually explains that +4 in the digital domain is actually -15 db from +4 in the analog domain, for headroom and clipping reasons.


As you mentionned, Don, even though the manual states +4 dBu on all outputs, you can see farther in the "maximum volatage gain" the difference from the Alt 3/4 and other busses. They all differ... so what's the reference?

The Main out (TRS) and other outputs have an extra 10 dB with the fader or aux sends knobs... so let's remove 10 dB from these outputs which gives :

STEREO LINE INPUTS TO :

MAIN OUTS (XLR) = 36 dB
MAIN OUTS (TRS) = 30 dB
AUX SENDS (TRS) = 35 dB
ATL 3/4 (TRS) = 24 dB

Ok, i have a 15 dB loss om my meters from alt 3/4 out back in the Mackie, and the closest i can get is by "presuming" the meters do monitor the MAIN OUTS (XLR) (36 db) which makes a difference of 12 dB ...

But ... the manual says : "When 0 dBu (0.775v) is at the outputs, it shows as 0 dB VU on ther meters "

But which outputs ??? They all have different gain settings !!!


I'll ask the question to the Mackie tech and see what he says...

Thanks!

Phil

 

[philboy]

Well, it looks like Mackie support won't answer this one for me. Too bad.


Phil

 

[orksnork]

how old is the unit???

if it's still new enough....take it back to where you bought it...say it's having some problems and swap it for a new one....


if the problem is still there...it's obvious a design issue

 

[philboy]

The Mackie support finally replied. I suppose they were quite busy which explains the delay for the reply. They said they were sorry for the delay and kindly mentionned they would send a replacement mixer and from there we'll see if the problem persists. I think this is very prefessionnal.

Here is a part of the answer :

" ..... It does sound like you could be having a problem but I would like to clarify a few things for you we before we go on.

When you are reading in the manual about the maximum voltage gain it is referring to the amount of gain that can be applied to the output.

When it is stated that a unit has a +4 dbu output that is referring to the nominal operating level of the unit not the maximum output level so yes alt 3/4 is a +4 dbu output.

If your DAW app was seeing 0 db or over you would be clipping. if you are seeing 15db loss in signal coming from the onyx 1220 alt 3/4 output with the gain knob and fader set at the U position it would show up at around -30db on the digital meter in you software not -15.

You should on the other hand be able to connect the alt 3/4 output back into another channel on the console with everything set to the U position.

If you have the fader and gain knobs set to the U position on both the channel sending and receiving the signal you should be seeing a relatively close signal match with in a db or two but not a 15db difference by coming back in to the console .... "

So it looks like i had a bad unit... hopefully it's not a bad design... we'll see.

Thanks everyone for your help!

Regards
Phil