(Focusrite) interface Monitor control query

[Reuben Anstey]

Hi,

This might seem a strange ask, but on an audio interface (in this case a focusrite) at what point in the monitor control’s movement do the outputs provide the standard line level signal?

Is it fully clockwise, with anything less is just a reduction of it?

Or is the monitor control designed to provide some additional gain?

Thanks in advance!

[Arpangel]

Maximum Output Level
16dBu
Impedance
100Ω

Found this on the Focusrite website, as long as you’ve got a "usable range" all should be fine if you’re feeding it into your monitors, if you’re connecting it to a mixer or similar you can calibrate it to suite the inputs, and check it on your meters.
Just wondering, why is it a concern?

[ef37a]

Interface schematics are rare beasts but I did find one for a 2i4 and it would seem the final output stage is post the "master" VC and has a gain of about 6dB. I can also only assume the output is "impedance balanced" since it only shows one amplifier and not the TRS sockets.

And, as with Mr A...why?

Dave.

[Hugh Robjohns]

This might seem a strange ask...

It does!

... but on an audio interface (in this case a focusrite) at what point in the monitor control’s movement do the outputs provide the standard line level signal?

I'm afraid that's an impossible question to answer without a lot more information, because it depends on the maximum output level the interface can deliver (+16dBu, according to Arpy), the attenuation introduced by the control, the nominal operating level of your DAW system — or average level of the audio — (-20dBFS etc), and what you deem to be a standard analogue line level (+4dBu, 0dBu, -10dBV etc).

Is it fully clockwise, with anything less is just a reduction of it?

The control normally serves as a digital attenuator, with zero attenuation when flat out, and around 10-12dB attenuation at around 2 O'clock.

Or is the monitor control designed to provide some additional gain?

It would be unusual, and I can't think of any that can provide gain.... but it's not technically impossible if a manufacturer wanted too.

What problem are you trying to resolve?

[Reuben Anstey]

Thanks all for indulging me and for your time in responding

Chain is

MainStage - focusrite 1820i - (balanced input into)Crown xli 800 power amp- some old large peavy cabs of unknown power handling/impedence

I guess my concern is if it was possible to overdrive the power amp inputs by winding up the interface monitor control too far….hence wondering where should this be set so the power amp is getting a standard line level feed.

Many thanks!

[ef37a]

Thanks all for indulging me and for your time in responding

Chain is

MainStage - focusrite 1820i - (balanced input into)Crown xli 800 power amp- some old large peavy cabs of unknown power handling/impedence

I guess my concern is if it was possible to overdrive the power amp inputs by winding up the interface monitor control too far….hence wondering where should this be set so the power amp is getting a standard line level feed.

Many thanks!

The Focusrite puts out +16dBu (at 0dBFS) and the Crown can be set for full output for either 0dBu or +4dBu so you have plenty of drive in hand! Where you set things depends on several factors including which fader is the "master" for PA output.

That power figure is for an 8 Ohm load. You can measure your speakers and if 8R they will read about 6 Ohms, DC resistance is always about 75% of nominal impedance almost regardless of the make and size of speaker.

Dave.

[Hugh Robjohns]

I guess my concern is if it was possible to overdrive the power amp inputs by winding up the interface monitor control too far

Potentially yes...

The XLi800 spec says it delivers its full output power for an input voltage of 0.775 or 1.4Vrms (depending on its settings), which translates as 0dBu or +5dBu. The Focusrite has a maximum output of +16dBu... which is a least 10dB higher.

But, as I mentioned earlier, you can only reach +16dBu from the Focusrite if your Mainstage audio peaks up to 0dBFS. If your peak signal level is -10dBFS, for example, the max analogue output level from the focusrite would be only +6dBu...

Moreover, and importantly, the amp has input attenuator controls on the front panel which you can turn down to prevent it being overloaded by the potentially high signal from the interface.

….hence wondering where should this be set so the power amp is getting a standard line level feed.

It's not really about a 'standard line level feed'... it's about not sending too much level which would overloading the amp (and could destroy your speakers), but sending enough to generate adequate SPL for your gig.

If I were you, I'd start with the amp controls turned right down and then turn them up until it's loud enough (without the amp clip lights coming on).

[Reuben Anstey]

Thanks for all your help everyone...soz for late reply