Noise floor measurements

Orvillain

Rock Star
Edgelord
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4,542
I always use my effects in front of the amp. Even with high-gain. Coz I prefer the sound and the interaction between the effects and preamp. But the trade off is noise. So I'm always curious about keeping the noise floor as low as possible. I did some measurements earlier for a bunch of stuff.

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Diezel D-Moll. Channel 3. Set for a high-gain rhythm sound. Neve DI in line with poweramp output. Preamp8 on Discrete 8 audio interface. Set to mic level 48v for Neve DI. 0dB on the preamp.

All pedals set to buffered bypass where possible. Power source is a Strymon Zuma.

All measurements in dB as measured by the Ozone 9 meters.

Baseline noise level from amp with no guitar:
RMS: -83.2 PEAK: -72.4

Baseline noise level from amp with guitar with volume rolled down:
RMS: -82.2 PEAK: -71.8

Noise level from amp with Boss LS-2 in the signal path but not enabled:
RMS: -76 PEAK: -66

Noise level from amp with Boss LS-2 in the signal path and send A connected to return A, and enabled:
RMS: -73 PEAK: -62

Noise level from amp with Boss LS-2 in the signal path, with the Eventide H90 in the LS-2's loop A:
RMS: -70.3 PEAK: -59.4

Noise level from amp with just the Eventide H90 in the signal path:
RMS: -72.1 PEAK: -62.3

Noise level from amp with just the TC Electronic Flashback X4II in the signal path:
RMS: -77.1 PEAK: -67.2

Noise level from amp with Boss LS-2 in the signal path, with the TC Electronic Flashback X4II in the LS-2's loop A:
RMS: -71.8 PEAK: -61.5

Noise level from amp with Boss LS-2 in the signal path, with the Eventide H90 and then TC Electronic Flashback X4II in the LS-2's loop A:
RMS: -68.7 PEAK: -58.3

Noise level from amp with Boss LS-2 in the signal path, with the TC Electronic Hall of Fame 2 X4II and then TC Electronic Flashback X4II in the LS-2's loop A:
RMS: -70.8 PEAK: -60.5

Noise level from amp with only the TC Electronic Hall of Fame 2 X4II and then TC Electronic Flashback X4II in the signal path:
RMS: -75.6 PEAK: -65.5

Noise level from amp with Lehle Mono Volume pedal in the signal path, with the pedal at full:
RMS: -77.8 PEAK: -67.4

Noise level from amp with Lehle Mono Volume pedal in the signal path, with the pedal at minimum:
RMS: -80.9 PEAK: -70.4

Noise level from amp with Boss DD-500 in the signal path:
RMS: -77.7 PEAK: -67.4

Noise level from amp with Boss DD-8 in the signal path:
RMS: -72.7 PEAK: -62.2

Noise level from amp with just the MXR M300 Reverb in the signal path:
RMS: -77.4 PEAK: -66.6

Noise level from amp with just the Boss ES-5 in the signal path, with no loops enabled:
RMS: -80.1 PEAK: -69.6

Noise level from amp with just the Boss ES-5 in the signal path, with 1 loop enabled and connected with just a jack cable:
RMS: -79.9 PEAK: -69.0

Noise level from amp with just the Boss RV-5:
RMS: -75.5 PEAK: -61.3

Noise level from amp with just the Hardwire RV-7:
RMS: -74.1 PEAK: -63.9

Noise level from amp with just the Dunlop Crybaby BB535:
RMS: -73.0 PEAK: -62.5

Noise level from amp with just the Boss EQ-200 in the signal path, but bypassed:
RMS: -78.0 PEAK: -66.7

Noise level from amp with just the Boss EQ-200 in the signal path, enabled but all bands at unity and not boosting anything:
RMS: -75.3 PEAK: -64.7

Noise level from amp with these pedals in front -
Dunlop Crybaby BB535
Lehle Mono Volume pedal
Eventide H90
TC Electronic Flashback X4II
Boss EQ-200 (enabled but unity)
RMS: -66.5 PEAK: -56.2

Noise level from amp with Axe FX III plugged into the front using output 3, with boost/pad set to 18dB:
RMS: -75.5 PEAK: -64.8

Noise level from amp with Line 6 Helix plugged into the front using main out L, set to instrument level, with the volume knob on the Helix decoupled from the main outs:
RMS: -71.4 PEAK: -60.4



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What I get from that is:

LS-2 is noisy. Not really suitable for removing pedals out of your signal path if you're concerned about noise.
H90 is noisier than the TC effects.
With a string of digital pedals, noise-floor from the AD/DA stages is culminative, and it is quite noticeable.
The Axe III and Helix are the least noisy options as expected, because if you use them standalone then you've only got one AD and one DA stage to contend with. Axe III edges it slightly by having the boost/pad parameter to optimize the DAC.
Boss ES-5 is quieter than the LS-2. I'm going to go out on a limb and say the GigRig G3 would be a similar story.
When you're actually playing, this stuff doesn't matter so much. But if you're doing ambient stuff with various distortion stages after the ambient effects, then you're boosting noise to quite a different degree than the players who whack everything into the effects loop. Thus people who use effects loops probably don't understand what the pissing and moaning about noisy pedals is all about.
The amp itself is VERY quiet. This lends credence to the idea of going straight into the amp, if you're concerned about noise.
But then you simply cannot get the kinds of tones you may be looking for.
As ever - setting up a guitar rig is a careful balancing act of several components all working together, hopefully in harmony.

Workflow is super important. Bending down to futz with the Helix, or a Fractal FM9, or worse turning around to menu dive with the Axe FX III, doesn't hugely appeal to me. I like the tactile nature of a bunch of knobs on a pedalboard.

Finally - what I would say is quite often the differences between algorithms, in contrast to popular opinion, become heightened. Distortion is like compression, where it brings out details in the tails and in the overall signal path, that you wouldn't normally hear without it.

So H90 versus TC Flashback versus DD-8 versus Carbon Copy.... in front of a cooking amp, the sonic differences are much more apparent.

Oh, an addendum to that last bit - The Helix stands out to me as having the poorest delays and reverbs versus the other bits of kit.
 
H90 doesn't have analog dry thru. TC pedals do.

Told you so! :rofl
I'm no electronic engineer, but it stands to reason that the noise is quantization noise coming from the AD/DA stages in each pedal. All digital pedals have these stages, and they're not all equal.

Having analog dry-thru doesn't change the mechanics of the DAC's.
 
Interesting. I am not at all surprised that the LS2 is noisy (afaik this has been common knowledge for a long time), but the H90 being noisy is more of a suprise considering it's one of the newest units on the market.

When I have time I should try to replicate this experiment with my setup which has a board full of Strymons. They definitely add some noise to the system but I don't think the noise increases much by adding more Strymons in line.

I'm not hugely bothered by noise unless it's ground loop noise or a particularly bad case of EMI getting picked up. I had a situation like this at home where just based on where I was facing there would be next to nothing or a lot of noise just plugging guitar straight to Axe-Fx 3. I have no idea what actually solved the problem because after putting my Axe-Fx 3 on a desk it's just gone.

PS. I think this would be more readable if you use the table feature (three dots after the quote icon).
 
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Here's the figures in a more digestible format. Sorted by RMS - quietest to loudest.
 
View attachment 3236

Here's the figures in a more digestible format. Sorted by RMS - quietest to loudest.

Diezel D-Moll. Channel 3. Set for a high-gain rhythm sound. Neve DI in line with poweramp output. Preamp8 on Discrete 8 audio interface. Set to mic level 48v for Neve DI. 0dB on the preamp.

All pedals set to buffered bypass where possible. Power source is a Strymon Zuma.

I want to follow in your footsteps and do the same, but I'm not quite understanding how you set this up and were able to obtain these measurements. Do you mind explaining in more simple terms how I can do this?
 
I want to follow in your footsteps and do the same, but I'm not quite understanding how you set this up and were able to obtain these measurements. Do you mind explaining in more simple terms how I can do this?
Sure. So..... first thing you'll need is either a loadbox, or a DI you can put between your amp and cab, in order to get a line-level signal you can send to your DAW.

Once you have that, you can take a signal from your amp and measure the peak and RMS levels inside your DAW. I use Reaper, but most DAWs will at least allow you to load a plugin called DpMeter5: https://www.tbproaudio.de/products/dpmeter

That gets you decent RMS measurements.

Then it is just a case of taking the measurements from whatever signal you want. Always take a baseline measurement so you know what you're comparing to. In my case it was just the amp by itself set to a high-gain sound, so I knew it was a "worst case" scenario for noise. As you can see, ultimately pedals in front of the amp can end up adding almost 20dB to the noise floor of the entire system.

The argument for a pedal switching unit that keeps pedals out of the signal path until you need them, is strengthened by such an experiment. If you're using a multi-fx unit, you can often get better performance than multiple stacked digital pedals; because of quantization noise from the AD/DA stages in each pedal.

Please note - a lot of people put their spatial effects in the FX loop of their amp, so they don't ever experience as high noisefloors as I do when I run them up in front of the amp. But that's the trade off if you want those tones... overall higher noise floor.
 
Sure. So..... first thing you'll need is either a loadbox, or a DI you can put between your amp and cab, in order to get a line-level signal you can send to your DAW.

Once you have that, you can take a signal from your amp and measure the peak and RMS levels inside your DAW. I use Reaper, but most DAWs will at least allow you to load a plugin called DpMeter5: https://www.tbproaudio.de/products/dpmeter

That gets you decent RMS measurements.

Then it is just a case of taking the measurements from whatever signal you want. Always take a baseline measurement so you know what you're comparing to. In my case it was just the amp by itself set to a high-gain sound, so I knew it was a "worst case" scenario for noise. As you can see, ultimately pedals in front of the amp can end up adding almost 20dB to the noise floor of the entire system.
Very interesting, thank you very much! I'm going to try to sort this out and have a go at it.
 
When i tried to get those, my noise floor slapped me in the face and marched off in a huff.

Noise floors: can't live with em, can't live without em
Screenshot_20230901_094517_Brave.jpg
 
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