EMG @ 18v red-lighting FM3 with 18dB pad

sumitagarwal

Inspired
Brief background: my playing method is all about getting maximum dynamic range, while maintaining clarity, out of my guitar without touching any external controls or switches.

Currently that means running an EMG 81 in the bridge at full volume, close to the strings and digging hard with my right hand + running an EMG 60 in the neck at ~2 volume, backed far away from the strings, with a soft, dynamic touch.

With this setup running into a the dimed 6CA7 Plexi model I'm able to get some of the best aggressive bridge tones and sparkly clean neck tones I've ever had simply by flicking my pickup switch. I've always been a PAF guy, sometimes vintage-style Strat neck pups, but man am I loving the clarity that EMG's retain when dialed back!

Anyways, the only problem with this is what generally gets referred to with EMG's as compression. My take is that this isn't traditional compression, but rather a higher overall output level with an abrupt limiter. It makes sense that for a conventional metal tone this is perfect, because you can consistently drive a rig hard, keep downstream gain at lower levels, without overwhelming the rig with huge peaks. As everyone knows, that's basically a boost pedal.

But for my playing and style I much prefer richer finger dynamics, so I duct-taped an 18v hack into my tiny Explorer control cavity (pics of my 6x CR2032 stack). Sounds way better to me, and the EMG 60 especially sounds phenomenal. However, here's where the problem the question is: on the EMG 81 at 18v I regularly blip the red input LED on my FM3, even with the 18dB pad on. Backing down the 81 helps with these peaks, but loses some of that high-gain sound.

So FINALLY for the real real question here: I know the red LED is supposed to represent -6dB. I really am looking to fine tune my 81 pickup height and possibly experiment with other voltages too (i.e. 15v or 12v), to find my best maximum output without clipping. But in order to do this I need a real way to check the input clipping, not the loosey-goosey -6dB red LED. How can I do that?
 

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Record a DI, zoom in on the waveform and look for clipped peaks.

I can't remember if the onscreen clipping indicator was added to the FM3, but I think it was. It pops up in red text over the mini tuner if the input is clipping. It's much better indicator than the front panel input LED meters.
 
Record a DI, zoom in on the waveform and look for clipped peaks.

I can't remember if the onscreen clipping indicator was added to the FM3, but I think it was. It pops up in red text over the mini tuner if the input is clipping. It's much better indicator than the front panel input LED meters.
Yea, I was thinking DI into a computer would be ideal.

Rather than analyzing the waveform I was hoping maybe I could do something like selecting the input (should I use channel 5, 6, or 5+6?) and in my computer setting that track to +18.1dB. If my output is going above 0 dB, then that would mean I'm hitting maximum input on the FM3, right?

My numbers and assumptions might be wrong, but that's where my head is at.
 
I think it depends on the input pad setting for the FM3. If you check the input waveform and see were the clipping point is in the track you should be able to determine how much to boost the level to make it hit 0 dB in the DAW for checking. For example if the flat peaks are at something like -12.5 dBFS, then boost the track by 12.5 dB and the track clip indicator should then line up.

You can use USB Inputs 5, 6, or both. They carry the same signal since the input from the instrument input is mono. For reamping, it's easiest to use 5&6 to a stereo track as sending that back to the grid will give you the same level as live without any adjustments.

BTW the CR2032 coin cell batteries have about half the mAh rating of a typical 9V battery, so they'll work, but you'll likely get about half the battery life with those. The CR name indicates the size of the battery usually, so 2032 is 20mm wide and 3.2 mm thick. There's the CR2354 (23 mm wide and 5.4mm thick) that's rated about the same as a 9V (560 mAh) and also the CR2477 (24 mm wide and 7.7 mm thick) that's rated for 1000 mAh for even better battery life. 9V batteries are 26.5 mm wide so the bigger cells might still fit.
 
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I think it depends on the input pad setting for the FM3. If you check the input waveform and see were the clipping point is in the track you should be able to determine how much to boost the level to make it hit 0 dB in the DAW for checking. For example if the flat peaks are at something like -12.5 dBFS, then boost the track by 12.5 dB and the track clip indicator should then line up.

You can use USB Inputs 5, 6, or both. They carry the same signal since the input from the instrument input is mono. For reamping, it's easiest to use 5&6 to a stereo track as sending that back to the grid will give you the same level as live without any adjustments.

BTW the CR2032 coin cell batteries have about half the mAh rating of a typical 9V battery, so they'll work, but you'll likely get about half the battery life with those. The CR2354 battery (a bit wider and thicker) has a mAh rating similar to 9V batteries.
Thanks man!!

My understanding is that the CR2032 is about half the mAh as a 9V, so if I was stacking 3 to hit 9 volts it would actually last a bit longer than a 9V battery, but I don't understand these things so good.

I wasn't even aware of the CR2354!! This seems perfect. 4 of them at 12V or even 5 of them at 15V might just be ideal.
 
If you're stacking the batteries in series, you're increasing the voltage, but not the capacity. They have to be in parallel to increase the capacity, but that does not increase the voltage.
 
If you're stacking the batteries in series, you're increasing the voltage, but not the capacity. They have to be in parallel to increase the capacity, but that does not increase the voltage.
Thanks... yea, my understanding is not state of the art =\

Just tried and doesn't seem like the FM3 (FW 7.00) has the clipping indicator on the mini tuner. Even when I set the pad to 0 and peg the red LED like crazy.
 
Yeah I scanned through the FW release notes and it doesn't look like that got ported to the FM3 yet. You'll have to use the DI route for close inspection.
 
Coincidentally, stacked battery cells is exactly how regular 9V batteries are made. They have six 1.5 volt cells in series.

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Whut?! I had no idea! I knew that's how A23 batteries were made so that's where I got the idea, but A23's are so space inefficient with so much non-capacity metal in there. That's why I tried CR2032, but your CR2354 idea is even better!

I'm also wondering if there's any practical difference between clipping the EMG preamp versus clipping the FM3 input. Maybe this is basically the same as running the bridge pickup lower than 18V? It's really the neck 60 where I want that high voltage to keep the dynamics and get as strong of a signal as possible before I hit that rolled down volume knob.
 
I believe the EMG preamp is compressing and soft limiting the signal, where as the FM3 input would be clipping hard and sound much worse. Both limit the dynamic range, but one does so more gracefully.
 
I believe the EMG preamp is compressing and soft limiting the signal, where as the FM3 input would be clipping hard and sound much worse. Both limit the dynamic range, but one does so more gracefully.
Hrm, so maybe the smart compromise is trying 15V, although I was tempted to bump up and try 21V before I noticed the input indicator.

Maybe there's a smart way to rig up the Output 2 clip LED to be a proper input clipping indicator? Run a second line from the input block to the Output 2 with no effects on that one, and the Output 2 gain set correctly to clip if the input gets too hot?
 
Ok, so this is super interesting.

I tried connecting Out 2 to In 1 and removing the input pad while adjusting the Out 2 block level until I could reliably blip the Out 2 Clip LED. Here's what I found.

0 dB pad - can blip at 14.4 dB or higher
6 dB pad - can blip at 8.5 dB or higher
12 dB pad - can blip at 2.6 dB or higher
18 dB pad - can blip at 2.4 dB or higher

This suggests to me 2 things: 1) the pad really is helping retain a lot more dynamic range, since I have to drop the Out 2 level as I increase the pad, and 2) with the 18 dB pad I suspect we really are retaining most of the dynamic range of the EMG's, but losing some. For the other pad settings there was ~6 dB difference in Out 2 level as I changed it up, but only 0.2 dB difference on the last one.

Does that mean that at 18V I'm leaving ~5dB of dynamic range getting clipped by the FM3 input?
 
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No, it means you've reached the pad level at which the signal is no longer consistently clipping and the higher peaks are being maintained to continue on and clip the output. At the lower setting, those peaks are gone so you're able to boost the signal more in their absence.

Checking the input DI waveform is a more sure fire way to check for clipping if you're going to be adjusting the pad.
 
Ok, stopped being lazy and connected up my laptop.

Here's some shots...
 

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Putting a dimed Micro Amp between the 81 and the FM3 and retried my earlier test:

0dB pad: 14.4 dB
6dB pad: 8.5 dB
12dB pad: 2.6 dB
18dB pad: 1.8 dB

Interesting!

Anyways, if nothing else I think the above values are useful for anyone who wants to set up Out 2 as an absolute clipping checker, right?
 
I believe the manual states that "tickling" the red is fine. I run one of my guitars guitar with 24v mod on the EMG's (81/60 also) and have no issues with clipping on full volume.
 
Is there no clipping indicator on the FM3 like there is on the Axe-FX? If not, is that intentional?
 
Is there no clipping indicator on the FM3 like there is on the Axe-FX? If not, is that intentional?
I dunno about intentionality, but I think my instructions above show how to make one (unless I'm wrong)

I believe the manual states that "tickling" the red is fine. I run one of my guitars guitar with 24v mod on the EMG's (81/60 also) and have no issues with clipping on full volume.
Maybe I have a weird right hand? I dunno. Running 10's in standard tuning.
.
 
I've done quite a few similar tests in the past with my fishman abasi pickups, and realized I need to set -18db to the Output block (applied it globally , to all my presets), to get rid of the clipping. Pickups are way too hot. With this setting, I could use the even 6db padding, but after more tests settled on 12db.
 
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