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Old 07-01-2020, 08:45 AM   #1
Schindigg
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Default Guitar signal limited/compressed before going into DAW?

Im having a potential issue with recording guitar into Reaper. It seems that the signal coming from my guitar is too hot maybe and getting compressed or limited before being processed by the DAW.

My signal chain is:
musicmann Jason Richardson 7 string
radial pro DI box
focusrite scarlett 2i2 3rd gen
reaper DAW
NeuralDSP Nolly pluggin

* The DI box is necessary because without it my guitar clips going straight into the interface even with the gain knob at 0.

*The only ways I've gotten the waveform to break out of the limit box is to either set the gain too high on the interface to where it starts clipping which is of course not good OR to engage the AIR switch on the interface which emulates a higher end preamp, which helps the signal/waveform to expand but when you zoom in on it it's still jagged and not round like it should be.

The tone sounds great but the waveforms are clearly getting compressed a little when im playing. You can see the top and bottom being sliced off. I have the gain knob on the scarlet set to where it stays in the green no matter how hard I pick (playing metal). Im not using the dB booster on the pickup.

Im nut sure if there is a setting i can change somewhere to help de-clip the signal or if i need to get a good declipping pluggin to use or what? Just seems weird when my signal isn't clipping the waveform is compressed somehow but when i AM clipping it allows the full waveform to come through.

Any help would be appreciated.
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Old 07-01-2020, 08:59 AM   #2
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“Electronics include a volume control with up to 20dB of boost...” So first of all check the battery and make sure it’s not near dead. Even still, with 20db gain on top of a humbucker I wouldn’t be terrible surprised if it was clipping a 9V circuit. I don’t think the DI is going to be the culprit, but you shouldn’t need it if you just plug the guitar into a line input. If the guitar getting distorted within its own circuitry, there’s probably not much you can do except turn that V pot down.

Then again, if you’re just going to distort it more with an amp sim, what’s the difference?
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Old 07-01-2020, 09:34 AM   #3
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I checked my battery with a tester and its still good. And the DI box just lowered the signal coming from the guitar enough to where i could actually apply some gain at all through the interface which helped the overall sound to be a little more saturated.

Iv been trying all kinds of fixes with a friend for a while now with no real result so for now Im just gonna keep the AIR switch on my interface on and keep rocking it. Its not perfect but its pretty close and the sound is still fantastic.

Thanks for the reply though!!!
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Old 07-01-2020, 09:42 AM   #4
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Clipping is a "bad kind" of limiting/compression...


What happens when you turn-down the volume knob on the guitar? I know... Guitar players hate doing that but it might be a solution, or at least a worthwhile experiment.


You could try an attenuator between the DI and interface.


But this is weird! "Normally", it's the analog-to-digital converter that clips (at exactly 0dB) and it looks like that's not happening. Of course, it's possible to clip/saturate analog electronics but I don't get how that could be happening. The preamp in an interface is normally designed to have more headroom than the ADC. And, you don't have an active pickup so there is no other active electronics, right?

I guess if the recording volume control (in the interface) is between the preamp & ADC it's possible to saturate the preamp without clipping the ADC...


It's also possible to saturate a transformer (in the DI box) but Radial has a very good reputation so I can't believe that's happening either.

Last edited by DVDdoug; 07-01-2020 at 09:48 AM.
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Old 07-01-2020, 09:48 AM   #5
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Quote:
Originally Posted by DVDdoug View Post
Of course, it's possible to clip/saturate analog electronics but I don't get how that could be happening.
Like Aschat inferred. Anything that amplifies a signal is bound to the amount of voltage that can be used to do that amplification. Your basic passive guitar can generate a volt or more peak to peak with just a barre chord, so with a 9V supply you got less than 4.5 volts on each side of the waveform. And most opamps can't even supply the full amount unless they are rail-to-rail designs meaning...

A gain of only 3 or 4 could cause the preamp to clip on a 9V supply. This is also the reason some guitar circuits (think very clean boost type stompboxes) use or can use 18V power supplies; simply for that non-clipping headroom. But if you are going to distort it anyway, it's just down to your ears. I'm sure this is also the reason some active guitar pickups are described as sounding "compressed".
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Old 07-01-2020, 10:08 AM   #6
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Originally Posted by karbomusic View Post
A gain of only 3 or 4 could cause the preamp to clip on a 9V supply.
That’s 3 or 4 TIMES gain, about 9db. The 20db this gives is 10x the input. 1V is easy for a humbucker, so you’re trying to make the 9V circuit (which is really more like 7V) pass 10V and it just won’t.

And yes, even that 7V is probably a bit much for the instrument input of your interface because that hole (or button or whatever) multiplies the whole thing by about 3 times again, so now the interface is trying to eat 21V which is definitely more than it can handle.

So instead we use a DI which divides the 7V down about 10 times and were sitting back at 0.7V. That into a mic preamp that probably has 6db minimum gain and now where at 1.4V which is a little low for line level, so you turn up the gain some to...

...what?

This is where I get stuck. What are you doing to this signal where anything other than a reasonably clean signal isn’t good enough? Is it going into an amp sim, and you need a certain level hitting that to get the breakup you want? There’s plenty of clean gain available in Reaper. The amp sim itself should have a sort of “wrapper” with an input gain control that has nothing to do with the controls on the amp itself, but if it doesn’t you can just grab any gain plug you want. I’d lean toward ReaEQ myself, cause then it’s there if you want to actually...like...EQ it before the amp

The guitar itself is an active low impedance source that produces levels just a little low for line level. You could literally just plug the thing into a Line Input and go. Don’t need the Instrument hole. Don’t need the DI. Guitar>Line In>Reaper.

But you do need to turn down the guitar’s internal gain so it stops distorting itself.
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Old 07-01-2020, 10:18 AM   #7
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Originally Posted by ashcat_lt View Post
That’s 3 or 4 TIMES gain, about 9db. .
Isn't 3 or 4 times 1.2V approaching > 4.5V or can we halve the 1.2 for this comparison?
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Old 07-01-2020, 10:22 AM   #8
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Originally Posted by karbomusic View Post
Isn't 3 or 4 times 1.2V approaching > 4.5V or can we halve the 1.2 for this comparison?
First, my quote there is simply doing the Ratio to dB conversion in hopes of avoiding some confusion. I guess maybe that backfired...

Second 1.2V p2p times 4 is 4.8V p2p. That’s only 2.4V on either side of center.
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Old 07-01-2020, 10:27 AM   #9
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Quote:
Originally Posted by ashcat_lt View Post
First, my quote there is simply doing the Ratio to dB conversion in hopes of avoiding some confusion. I guess maybe that backfired...

Second 1.2V p2p times 4 is 4.8V p2p. That’s only 2.4V on either side of center.
Perfect, thanks!
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Old 07-01-2020, 01:57 PM   #10
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....or described as 2.4v peak (not necessarily a simetrical waveform!)

Where does the 9v battery supply come into the equation. If it powers some of the circuitry somewhere then clearly some attenuation is required as you have described.

Can I ask of you two, not being a guitarist myself (except trying to twang an acoustic without much success!)....

What is a guitar hole?

I understood the main reason for a DI box is to provide a high impedance load to the pickup(s) preventing bass loss. Why would a lower impedance line in be ok? (Ignoring level needs)
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Old 07-01-2020, 02:12 PM   #11
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Quote:
Originally Posted by Allybye View Post
Where does the 9v battery supply come into the equation.
It’s an active guitar. The quote in my first reply is from the manufacturer.
Quote:
What is a guitar hole?
Sorry, I often refer to jacks as holes. Like stick the plug in the hole where it fits. Many interfaces have dedicated “instrument” inputs and by “instrument” they mean “passive guitar”, thus “guitar hole”.

Quote:
I understood the main reason for a DI box is to provide a high impedance load to the pickup(s) preventing bass loss. Why would a lower impedance line in be ok? (Ignoring level needs)
Again, it’s an active guitar. The internal circuit should be fine driving a lower Z line input.
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Old 07-01-2020, 02:28 PM   #12
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Ahah!
Thanks. I hadn't appreciated it was active!

Note to self...must get used to this modern terminology! -

Socket = hole = plug socket (in some people's minds, well in the silly UK anyway! Who started that one?).


Does seem that +/- 9v batteries would be more sensible. We wouldn't design a preamp with such a low amount of headroom!

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Old 07-01-2020, 08:43 PM   #13
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Quote:
Originally Posted by Allybye View Post
Does seem that +/- 9v batteries would be more sensible.
It's actually a thing - especially among bassists - to "mod" an active instrument to run off 18V. This is usually literally just two batteries in series. As long as the opamp can handle 18V rails and the caps can pass 18V safely, it will work.

But that brings us back to "why?" 18V p2p is a HOT signal. It'll clip some Line Level inputs and will completely destroy anything that's "expecting" a guitar. Yes, it's true that louder sources are better for S/N because we don't have to amplify the noise that gets added in between quite so much, but in most cases the noise from the pickup itself just swamps out any noise that might be added in the cable, so at least after a certain point, it's not going to make enough difference to matter.

Now, I'm only really speculating that this might be the O/Ps issue, but the information I have leads me to believe that the signal is running into a limit before it even gets to the DI, which means inside the guitar's own circuit. If that's the case, it's probably just because the guitar's Volume knob is turned up too far. 20db gain is causing it to clip. If you don't want it to clip, don't add 20db gain. You should be able to get quite a healthy signal without clipping that amp, so stop clipping that amp.
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Old 07-03-2020, 06:10 PM   #14
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Quote:
Originally Posted by ashcat_lt View Post
It's actually a thing - especially among bassists - to "mod" an active instrument to run off 18V. This is usually literally just two batteries in series. As long as the opamp can handle 18V rails and the caps can pass 18V safely, it will work.

But that brings us back to "why?" 18V p2p is a HOT signal. It'll clip some Line Level inputs and will completely destroy anything that's "expecting" a guitar. Yes, it's true that louder sources are better for S/N because we don't have to amplify the noise that gets added in between quite so much, but in most cases the noise from the pickup itself just swamps out any noise that might be added in the cable, so at least after a certain point, it's not going to make enough difference to matter.

Now, I'm only really speculating that this might be the O/Ps issue, but the information I have leads me to believe that the signal is running into a limit before it even gets to the DI, which means inside the guitar's own circuit. If that's the case, it's probably just because the guitar's Volume knob is turned up too far. 20db gain is causing it to clip. If you don't want it to clip, don't add 20db gain. You should be able to get quite a healthy signal without clipping that amp, so stop clipping that amp.


Just wanted to reply, im not using the 20dB booster, you have to manually engage that by pushing in the volume knob. And im think like you its something with my guitar. Ive reached out to MusicMann and they say they haven't encountered this before so I don't know.

Here is a pic of 2 tracks, they are both a clean signal with no pluggins.
The signal chain is //guitar, di box, interface, reaper//

The first track is with the gain knob on the interface at 3 (or 9 o'clock)
The second track is with the gain knob at around 5 (or 11 o'clock) This is as high as i can turn it before the green light starts to turn yellow.

I will experiment with lowering the volume knob and see what results that gets me.
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Old 07-03-2020, 06:40 PM   #15
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The 2i2 2nd gen is notoriously loud and clips guitars, that is true. If you have an active guitar as you say, just engage the line-in switch, or leave it off but turn the volume down from the guitar. You won't lose tone this way.. Skip the DI box. You will get a slightly different tone and higher noise floor potentially from the line-in method.

Also another cause could be bad batteries (not dead batteries... just crappy ones) or a pickup that's outputting more than the following circuitry can handle, often a nice effect to be honest.
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Old 07-04-2020, 01:39 AM   #16
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Quote:
Originally Posted by Fergler View Post
The 2i2 2nd gen is notoriously loud and clips guitars, that is true.
Specs say second gen accepts a notch bigger signal than the 3rd gen (+13dBu vs 12.5). Both of those seem well more than enough to me, how loud is this guitar? Crazy it requires an additional DI. My interface says "max +8dBu" and it accepts mid-high output passive humbuckers no problem on like 30% on a gain knob.
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Old 07-04-2020, 02:27 AM   #17
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See post #11 from the cat.
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Old 07-04-2020, 03:04 AM   #18
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Simple google problem "where to plug the active guitar" nets infinite amount of infinitely long forum threads that leave you even more confused than you already were. That's why I'll avoid active guitars as long as I can

(altough active bass doesn't do any weird things whilst plugged into Hi-Z - gives another confusing riddle of "if knobby bass with a battery is actually active" tho)
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