MTRX Studio distortion on outputs

[menno1000]

Originally Posted by RobertDorn

faders in DADMan do trim the analog output / determine the headroom to match your analog equipments headroom. Actually in steps of 0.1dB so very accurate.

Ok, if that is the case, then there is something wrong

Don't exactly understand what you mean with the 6dB button.

the is on the DA side of DADman a button to ad 6 dB of output gain. When you engage it you can hear relays click inside the MTRX st.


Cadac Live can do up to +21dBu , S-type can handle up to +24dBu

The Cadac is a vintage console. I have to add gain to get a normal level.


The MTRX Studio does up to +24dBu on the D/A , which actually is 4dB louder than for instance the Lynx. So there must be going on something else.

The Lynx outputs in my studio about 12 dB more signal.

[RobertDorn]

ah ok, that 6dB button is a MTRX Studio only button. The monitor outputs (so the TRS sockets on the unit) have up to +24dbu headroom by default, the line outputs up to +18dBu . Not sure how that +6dB button works exactly in practice, as I don't the studio but the MTRX. But as it seems from the manual that button scales up the analog line outputs from +18dBu to +24dBu . If you have the Cadac live which can handle up to +21dBu , you could click the +6dB button and trim off 3 dB to output exactly +21dBu . Or, if you want to match your Lynx Aurora for instance, which is +20dBu on the outputs, click the 6dB button and trim off 4dB.

[menno1000]

Originally Posted by its2loud

@RobertDorn, Are we just typing at the same or are you ignoring my input here?Cuz we are saying the exact same things. Just asking cuz I’ll bow out if you two would like to carry on.

Thank you guys both for your input! Highly appreciated!

I am not at the studio right now. But i'll do your test as well to see where i am exactly in the dB range.

Although i did the test this in an implicit way.
I output a mix trough PT at lets say a safe max -1dB FS, garded by af FABfilter limiter. Next i did set the desired level in DADman at the levels. Not even close to the plus 18dB as indicated as example in the Avid instructions page. Then i get a lot of distortion. It's not the console (analog Cadac) or the passive monitor control. I can dim the monitorcontrol. It is MTRX. that sends out a distorted signal.

[menno1000]

Originally Posted by RobertDorn

ah ok, that 6dB button is a MTRX Studio only button. The monitor outputs (so the TRS sockets on the unit) have up to +24dbu headroom by default, the line outputs up to +18dBu . Not sure how that +6dB button works exactly in practice, as I don't the studio but the MTRX. But as it seems from the manual that button scales up the analog line outputs from +18dBu to +24dBu . If you have the Cadac live which can handle up to +21dBu , you could click the +6dB button and trim off 3 dB to output exactly +21dBu . Or, if you want to match your Lynx Aurora for instance, which is +20dBu on the outputs, click the 6dB button and trim off 4dB.

Yes, that is the remarkeble thing, the lynx is a lot louder than the MTRX. I can reach maybe the same level but then everything above -12dBFS distorts. And i even have to ad gain on the console. Or turn up the gain on the monitor control for output 1 and 2.

Another question: Does your MTRX's show an digital overload on the meters? I cant even force one on mine.

[RobertDorn]

Originally Posted by its2loud

@RobertDorn, Are we just typing at the same or are you ignoring my input here?Cuz we are saying the exact same things. Just asking cuz I’ll bow out if you two would like to carry on.

Haha no worries men, we happend to reply at the exact same moment, didn’t want ignore anything:)

[its2loud]

Originally Posted by menno1000

Thank you guys both for your input! Highly appreciated!

I am not at the studio right now. But i'll do your test as well to see where i am exactly in the dB range.

Although i did the test this in an implicit way.
I output a mix trough PT at lets say a safe max -1dB FS, garded by af FABfilter limiter. Next i did set the desired level in DADman at the levels. Not even close to the plus 18dB as indicated as example in the Avid instructions page. Then i get a lot of distortion. It's not the console (analog Cadac) or the passive monitor control. I can dim the monitorcontrol. It is MTRX. that sends out a distorted signal.

I think it would benefit all parties in this thread to wait until you can get back into your studio and do a proper signal flow test from source to destination. If you send a 1k tone @-18dBFS from Pro Tools that should measure 0VU exactly on your console's analog input. Any other measurement, distortion at that level, or reduction in signal level would indicate an issue somewhere in the chain.

BTW, I'm referencing -18dbFS since that is the European scale for 0VU

[menno1000]

Originally Posted by its2loud

I think it would benefit all parties in this thread to wait until you can get back into your studio and do a proper signal flow test from source to destination. If you send a 1k tone @-18dBFS from Pro Tools that should measure 0VU exactly on your console's analog input. Any other measurement, distortion at that level, or reduction in signal level would indicate an issue somewhere in the chain.

I will do so. Variables are the way i set levels in DADman and how much gain i apply on the console. What would you suggest as a startingpoint in the DADman controlpanel?

[Tone_Mechanic]

I’ve experienced this with other equipment where there was a mismatch in balanced/unbalanced configurations, or an mis-wiring in the cabling (such as swapping “ground” with “-“ on an electronically balanced output feeding an unbalanced input).

Is that a possibility? Are the DB25 cables you are using factory built? The right pin out? Etc?

[menno1000]

Hi All,

Thanks again for all your comments. It is solved by all your contributions.

I did the test as its2loud suggested.

Tone_Mechanic is right. MTRX is sensitive to balanced /unbalanced.
This is the cause of the distortion.

The Lynx and Apogee don't react to that. The outputs sound the same.
If i connect the MTRX to an unbalanced input the output of the MTRX starts to distort quite soon: above 0dB in DADman.

The faders in DADman control the analog output. It has nothing to do with digital gain.

Some tape returns on old consoles are unbalanced. I also use the insert return as an unbalanced line input after EQ to skip electronics.

So users of old console/mixers: you can't do this with an MTRX.
MTRX is balanced only.

I also used an unbalanced monitor input. The Benchmark is allright with that. But the MTRX not.
Now it's connected balanced input and i can turn up the output to max without issues.

Thanks again all of you! So much wiser in 24 hours. And i can keep the MTRX Studio happily.

@Tone_Mechanic do you have fix for the unbalanced issue? A different way to connect balanced to unbalanced?

[BScout]

Originally Posted by menno1000

do you have fix for the unbalanced issue? A different way to connect balanced to unbalanced?

You can either wire the cable correctly for this type of connection
https://www.ranecommercial.com/kb_ar...p?article=2107
(it is best to make short patch cables that "adapt" than tinkering with a DB-25 breakout cable that is wired to the normal standard -- and then label those patch cables for what they are)

or you can use a balancer box. (There are a lot of different companies that make them)
For instance
https://www.ranecommercial.com/legacy/bb44x.html