How to use audio interface as spectrum analyzer? (Focusrite Scarlette 2i2 Gen3)

[PhoenixFieryn]

Hello, I'm looking to use the 2i2 g3 as a spectrum analyzer for headphone amplifiers and DACs. I understand it won't be the most accurate of things, but it's more of a fun experiment than anything. I was wondering how much power can I feed the 2i2's XLR input before I hook up a Topping A30Pro and Burson Soloist X3P to it. Is there something particular I have to do with the 2i2 before I start? INST toggle? Gain setting? I couldn't find any info in forums I've looked into or the spec sheet.
Let me know if this isn't possible at all.

Just to double-check, I would connect the XLR out (headphone level) of the amps to the XLR in on the 2i2, correct? I've seen other forums mention loopback mode, etc. not sure if that's relevant. Is there something different I have to do for amps and DACs? Very much a newbie on this topic.

Help would be appreciated, thanks!

 

[SIY]

Hello, I'm looking to use the 2i2 g3 as a spectrum analyzer for headphone amplifiers and DACs. I understand it won't be the most accurate of things, but it's more of a fun experiment than anything. I was wondering how much power can I feed the 2i2's XLR input before I hook up a Topping A30Pro and Burson Soloist X3P to it. Is there something particular I have to do with the 2i2 before I start? INST toggle? Gain setting? I couldn't find any info in forums I've looked into or the spec sheet.
Let me know if this isn't possible at all.

Just to double-check, I would connect the XLR out (headphone level) of the amps to the XLR in on the 2i2, correct? I've seen other forums mention loopback mode, etc. not sure if that's relevant. Is there something different I have to do for amps and DACs? Very much a newbie on this topic.

Help would be appreciated, thanks!

For best results and safest operation, use an analog interface like Jan Didden's Autoranger (which will also read out actual voltages rather than relative numbers) between the device under test and the Focusrite. With software like ARTA or REW or (if you're fancy) Virtins MultiInstrument, you can do some very good quality measurements if you spend the time learning the ins and outs of FFTs and what the parameters mean and do.

 

[PhoenixFieryn]

For best results and safest operation, use an analog interface like Jan Didden's Autoranger (which will also read out actual voltages rather than relative numbers) between the device under test and the Focusrite. With software like ARTA or REW or (if you're fancy) Virtins MultiInstrument, you can do some very good quality measurements if you spend the time learning the ins and outs of FFTs and what the parameters mean and do.

Thanks for pointing me in the right direction. I will take a look at the Autoranger you mentioned, it seems like what I'm looking for, though there appears to be a constraint on its supplies atm. The software you mentioned is also interesting, I only know of REW of the 3 and I will look into the other two.

In the meantime, I can connect the amps' XLR out to the XLR in on the 2i2 to test, correct?

Thanks!

 

[DVDdoug]

In the meantime, I can connect the amps' XLR out to the XLR in on the 2i2 to test, correct?

You probably have to use the TS/TRS plugs for line-input. I don't know if those inputs are balanced.

It doesn't seem to have "line" switch so I'm guessing the XLR inputs are microphone only and the "instrument" switch switches the TS/TRS connection between instrument and line.

You'll also probably have to figure-out a collection of adapters to "split" the headphone output into separate left & right connections for the Focusrite. ...I'm just assuming that you won't find the "perfect" adapter-cable.

 

[AnalogSteph]

You probably have to use the TS/TRS plugs for line-input. I don't know if those inputs are balanced.

They generally are.

You'll probably want to be able to use both input types. The line-in can take substantially higher levels (+22 dBu rather than +9.5 dBu in this case), while the mic in at high gain has input noise levels low enough to be dwarfed by output noise so that can be determined rather accurately once you have calibrated absolute levels.

(Level calibration is specific to a given input gain setting and output level. It is fairly easy with a multimeter sporting a mV~ range, preferably TrueRMS although accuracy without should also be fine as long as you're sticking with 50-60 Hz sines.)