Calibrating Input Level for Plugins

[BuckTennington]

Note: Please don't quote this entire post, I may want to edit and add information or clarify things.
You can just reply without hitting the reply button, Thank You!

My method of calibrating your Audio Interface and Helix Native to match Helix hardware.
The result is more accurate gain from Helix Native equal to the Hardware, the last thing you want is to unknowingly set your vintage Telecaster to be as hot as a shredding axe with 18v EMGs, which a LOT of people mistakenly do.


1. Generate a 1kHz sine wave test tone in your DAW.

The free DD SigGen VST works great: https://plugins4free.com/plugin/2801/
Allows 0.01dB level adjustments while holding Shift, very accurate.

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2. Send the sine tone to a free output on your Audio Interface and adjust level to read 500mV AC with a Volt Meter.

Send the sine to a free unused output on your audio interface, ie. NOT to your studio monitors unless you need a headache.
If your audio interface has 1/4" outputs use a regular guitar cable or RCA cable with a 1/4"-to-RCA adapter on the other end.
Set your Volt Meter to AC reading and adjust the output from your DAW so the 1kHz signal reads 500mV AC RMS on the other end of the cable.
The meter doesn't have to be true RMS because we are measuring pure undistorted sine wave.

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3. Find the threshold on Helix Floor hardware (you can skip this step).

This supposed to be exactly the same for all HX/Helix hardware, since I already measured it you don't have to.

Insert the other end of the 1/4" cable into the Guitar Input of your Helix hardware and add a single Hard Gate to the signal chain.
Find the Open level that the 500mV signal opens the Hard Gate, on my Helix it is exactly -15.3dB.

Hard Gate settings: Close: 0.0dB, Hold: 10ms, Decay: above 200ms.

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4. Loop back the 1/4" output into the Instrument Input of your Audio Interface.

If you did step 3, pull out the 1/4" from your Helix and stick it in the Instrument Input of your Audio Interface.

Your audio interface should have an Instrument button so turn it On, and set the Gain on ZERO.
Wait... you set your gain above zero? NOOB, don't talk to me ever again.

Joking aside, the only consistent setting (ie. NOT Random) of the Gain knob is zero, on my Focusrite Interface I almost hit clipping with my EMG81 guitar when I play hard with gain at zero, so I just keep it there.

The 500mV AC signal should still be running from your DAW and you should see the input LEDs light up (not shown in the picture).

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5. Calibrate Helix Native Input Gain.

First, add a Hard Gate to your chain and set the Open Threshold to the exact same level we found in step 3 with the HX hardware.
I have found that my Helix Floor opens at -15.3 dB with a 500mV AC RMS signal, this should be true to all HX/Helix hardware if the Guitar Input electronics are exactly the same across all SKUs.

Now, find the exact Input level by moving the little white slider in Helix Native until the Reduction bar opens/closes, you can use the mouse wheel for finer control.

This input level is your calibration value to that specific input on your audio interface with the preamp gain set to zero on that input, this should match the HX hardware and all the models should behave exactly like on the hardware.
The patches you create now with Native should accurately translate to any HX/Helix hardware without the need to re-tweak the Drive or Level setting of Amps and Pedals and vice versa.

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I hope you find this useful.

I calibrated the Apogee Duet iOS/Mac/PC to use with NeuralDSP and I determined that I have to decrease the input of the plugin by 0.8 db.

I'm a skeptical that I did this right because Apogge's website says the Hi-Z Max input level is 14 dBu. Apogee doesn't say which Duet this is for (i.e., all models or latest) https://apogeedigital.com/products/duet/specifications.

I had to turn the Duet output up to 0 db for the multimeter to read anything. Pictures below of my settings. Any help would be appreciated.

 

[StratsoundFan]

Apogee Duet for iOS/Mac/PC is the second generation of Apogee Duet 2, and yes, it is 14dBu. I have it as well, it's a great sounding audio interface. I like the hi-z input very much, and the headphone output is a perfect match for high impedance headphones. It pairs well with Sennheiser hd600. It's a great combo.

 

[MirrorProfiles]

I calibrated the Apogee Duet iOS/Mac/PC to use with NeuralDSP and I determined that I have to decrease the input of the plugin by 0.8 db.

I'm a skeptical that I did this right because Apogge's website says the Hi-Z Max input level is 14 dBu. Apogee doesn't say which Duet this is for (i.e., all models or latest) https://apogeedigital.com/products/duet/specifications.

I had to turn the Duet output up to 0 db for the multimeter to read anything. Pictures below of my settings. Any help would be appreciated.

what are you using the noise gate in logic for?

0.5V into a 14dBu input should be -17.8dBFS. You should need to boost NDSP plugins by 1.8dB to get from 14dBu to 12.2dBu. I think most Apogee stuff is 14dBu with gain at 0, but not sure if that’s true for older units

 

[BuckTennington]

what are you using the noise gate in logic for?

0.5V into a 14dBu input should be -17.8dBFS. You should need to boost NDSP plugins by 1.8dB to get from 14dBu to 12.2dBu. I think most Apogee stuff is 14dBu with gain at 0, but not sure if that’s true for older units

I used the noise gate based on OP method. Clearly I didn't know what I was doing

 

[MirrorProfiles]

I used the noise gate based on OP method. Clearly I didn't know what I was doing

Ha all good, was just curious if it was there for a reason or from something else. The gate in OP is specifically for Helix Native and would need to be the gate within that plugin.

Try following this guide:

 

[Sedaxel]

Ha all good, was just curious if it was there for a reason or from something else. The gate in OP is specifically for Helix Native and would need to be the gate within that plugin.

Try following this guide:

Using that method, my EVO4 throws +14.7 dBu... While Audient states +10 dBu. Too much difference, isn't it?

Using the tool inside Tonocracy, it results in +16.2 dBu.

 

[MirrorProfiles]

Using that method, my EVO4 throws +14.7 dBu... While Audient states +10 dBu. Too much difference, isn't it?

Using the tool inside Tonocracy, it results in +16.2 dBu.

Hmm, it seems strange that you're measuring different values with different software. Tonocracy matches my calculated values exactly.

Its hard to know how much tolerances vary on the interface (or if its related to power supply or a setting or something else), it could be down to how the multimeter is measuring (you could try a different voltage? some are more accurate at lower frequencies IIRC), or something else.

Do you have any other interfaces you can compare against?

 

[James Freeman]

for quoting the first post.

 

[Orvillain]

for quoting the first post.

I knew that was gonna come up when I saw it t'other day.

 

[Sedaxel]

Hmm, it seems strange that you're measuring different values with different software. Tonocracy matches my calculated values exactly.

Its hard to know how much tolerances vary on the interface (or if its related to power supply or a setting or something else), it could be down to how the multimeter is measuring (you could try a different voltage? some are more accurate at lower frequencies IIRC), or something else.

Do you have any other interfaces you can compare against?

Yeah... You're absolutely right.

I made a little mistake in Reaper. I was reading the peak in the DI track, but the signal entering was the master, instead of the sine wave track... So it was adding levels of both tracks. I fixed it, sending the sine wave direct to output (instead of the master to output), so DI track is safely receiving just the sine wave.

This way, it calculates exactly the same as Tonocracy, +16.2 dBu.

It doesn't match what Audient states in the specs, though.

 

[MirrorProfiles]

Yeah... You're absolutely right.

I made a little mistake in Reaper. I was reading the peak in the DI track, but the signal entering was the master, instead of the sine wave track... So it was adding levels of both tracks. I fixed it, sending the sine wave direct to output (instead of the master to output), so DI track is safely receiving just the sine wave.

This way, it calculates exactly the same as Tonocracy, +16.2 dBu.

It doesn't match what Audient states in the specs, though.

If you have another interface you can measure, itll help deduce where the problem is. If you measure another interface that is also 6dB out, you know your multimeter is giving a funky reading. Do you have another meter you can test with?

 

[Sedaxel]

If you have another interface you can measure, itll help deduce where the problem is. If you measure another interface that is also 6dB out, you know your multimeter is giving a funky reading. Do you have another meter you can test with?

No, I just have this meter (a brand new Aneng Q1). The old one I had didn't measure mV... It was too cheap, you know. This seems to be reading OK, at least DCV is spot on with some batteries I've got.

I've measured the Mooer GE250 input too... But there's no info on Mooer's manual to check it. And the input gain is not as a usual interface so you can lower it to the minimum, so it doesn't have much sense. With the usb record volume in its default value (50/100), the value is +6.6 dBu. Tonocracy gives the same result too.

When I had at hand another interface, I'll make the test.

Thank you for your help!!

 

[BuckTennington]

for quoting the first post.

Ugh! I actually did it right the first time but overthought it, deleted it, and then quoted the post!

 

[BuckTennington]

Ha all good, was just curious if it was there for a reason or from something else. The gate in OP is specifically for Helix Native and would need to be the gate within that plugin.

Try following this guide:

I used the sine wave utility in Logic Pro.
I had to turn the Dent's headphone out all the way up to 100% for the multimeter to read anything.
The sine level was -18 db.
The peak dBFS was -11.2.
My input dub value was 7.396.

What do you think I did wrong?

 

[SillyOctpuss]

John Cordy having a go at explaining this but in a very confusing way.

 

[Elf]

John Cordy having a go at explaining this but in a very confusing way.

He should had linked to this thread!

 

[James Freeman]

Cordy if you reading this;
Your Steinberg RT4 specifies "+8.5 dBV" which is a different unit than dBu.

dBV + 2.21 = dBu
https://www.extron.com/calculators/db-to-volts/


8.5 dBV + 2.21 = 10.71 dBu
To get to 12.2 dBu for Neural plugins subtract 1.5 dB in your DAW before the plugin.

 

[Jkist7]

I tried searching around in this thread, and I don't think its been covered yet. Anybody else have an RME Babyface Pro FS? Any idea what levels should be set to on this unit?

I use mostly Neural plugins, so I would be most interested in where I should set the Babyface for that use case. Here is the spec page, I am not knowledgeable enough to decipher it, but I am sure the number I am looking for is there somewhere:

Babyface Pro FS - RME Audio Interfaces | Format Converters | Preamps | Network Audio & MADI Solutions

RME Audio Professional Live, Studio, Recording and Broadcast Solutions. Unrivalled Quality, Performance & Stability MADI Interfaces, Converters & Preamps.

www.rme-audio.de

 

[MirrorProfiles]

I tried searching around in this thread, and I don't think its been covered yet. Anybody else have an RME Babyface Pro FS? Any idea what levels should be set to on this unit?

I use mostly Neural plugins, so I would be most interested in where I should set the Babyface for that use case. Here is the spec page, I am not knowledgeable enough to decipher it, but I am sure the number I am looking for is there somewhere:

Babyface Pro FS - RME Audio Interfaces | Format Converters | Preamps | Network Audio & MADI Solutions

RME Audio Professional Live, Studio, Recording and Broadcast Solutions. Unrivalled Quality, Performance & Stability MADI Interfaces, Converters & Preamps.

www.rme-audio.de

• Maximum input level @+4 dBu, Gain 0 dB: +13 dBu

so set your converters to +4dBu calibration, turn the gain to 0. You now have +13dBu of headroom, adjust in the plugin based on whatever you are using (for NDSP, boost 0.8dB).

 

[Jkist7]

• Maximum input level @+4 dBu, Gain 0 dB: +13 dBu

so set your converters to +4dBu calibration, turn the gain to 0. You now have +13dBu of headroom, adjust in the plugin based on whatever you are using (for NDSP, boost 0.8dB).

Perfect, just what I was looking for! Thank you so much! So I've basically been on the money anyways. I've been running +4 at 0 added gain. So the Neural stuff has been sounding pretty much as it should for me this whole time. Thats good to know, I've always been happy anyways. Just wondered if I was missing anything.

Thanks again MP!