Old 05-10-2022, 01:15 PM   #1
kokconut
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Default Fighting amp simulators noise

I'm using amp simulators for recording guitars silently and in the box. The tone and distorsion are as expected for a real world guitar recording but I have big noise when I let ring a note for long.

If I understand how amp sims work, they are not noisy per se. If we have an amp sim inserted in a track there is no noise as far as no signal is feeding the amp sim. But as soon as the track is armed, the amp sim amplifies the signal and generates a low level noise inheret of guitar amps. Its difficult to explaind with my poor english.

But the practical case is, when I record a guitar passage I have low level noise prior to the first plectrum stroke. This can be erased easily with a noise gate or editing the silence. The problem is when the last note or chord rings for long and fades away. As it loses volume the noise raises making useless half of the note tail.

I assume this is due to the "note volume/preamp noise" ratio, for as soon as the track is armed the interface preamp noise is being amplified by the amp sim, even when there is no cable conected to the interface input, so all the signal coming to the track is only the preamp noise floor.

I'm currently using a Presonus 44vsl and a Palmer Pan01 passive DI box. I have also tried to record the guitar conected directly to the instrument inputs, with the same result.

I calibrate the interface inputs with the knobs at noon, just enough gain for the stronger plectrum strokes to peak around -6 dbfs. So I think I'm optimizing the gain structure, but I can't get rid of the noise.


So, my questiones are:

Is there any way I could optimize even more my tracking signal, making it hotter so I can adjust a lower gain in the interface to reduce its preamp noise? Maybe I could use some kind of pedal that let me increase the guitar DI signal prior to the interface premap. It should add no noise and no coloration, as what I'm trying to record here is the raw guitar DI.

Or maybe I should change the interface and get another one with better/more silent preamps. I don't know if this could solve the problem or I'd be in the same situation.


Any help will be welcomed.
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Old 05-11-2022, 09:12 AM   #2
Boogieshoes
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It is highly unlikely, if you are using a reasonable audio interface to the PC/Mac that the pre-amps in there are the source of or contributor to the background noise.

You don't say what Amp Sims you are using. That said, many Sims actually model the kind of 'noise' a cranked amp. If also added pedals even as sims in line too, these would add to the noise modelled floor whilst everything is idling.

Add to that that as soon as you open the guitar volume your pickups will add some noise possibly picking up interference from other electrical kit nearby (computer monitors etc. are a prime source).

So it very much depends what tone shaping you are seeking, if its a high gain sound the issue is more pronounced. Careful use of guitar controls, its location to noise sources and any noise gate settings is your start point.
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Old 05-11-2022, 09:32 AM   #3
Frank Lee Scarlett
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I'm betting that you're using single coil pick-ups?

If so, that's where your noise is coming from, and the same thing would happen through a real amp.

I've used a lot of sims and, if I have a noise problem, it's never been the sim's fault. For sure, some sim settings will amplify the pick-up noise more than others, but so will an amp that's set up for a face-melting hard rock/metal solo.
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Old 05-11-2022, 10:58 AM   #4
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Quote:
Originally Posted by kokconut View Post
I'm currently using a Presonus 44vsl and a Palmer Pan01 passive DI box. I have also tried to record the guitar conected directly to the instrument inputs, with the same result.
I doubt they’re exactly the same result. The passive DI is a step-down transform which reduces the signal level fairly significantly. That requires more gain from the preamp and usually means more noise at the other end. The second rule of gain staging is to try not to turn something down just to turn it up again later. It WILL affect your overall S/N ratio, and if you did some simple tests you could prove it.

But it’s probably not enough to help because it’s probably not the major contributor to the noise. Guitars just in general have a much lower S/N ratio than anything in the interface, so there is like 20s of decibels worth of wiggle room before the guitar input signal is low enough that the interface noise matters much. With SC pickups through a DI, you might be on the edge. I know I could tell the difference going from DI to actual direct unity input (pedal buffer to line input), but kind of only because my guitars are mostly pretty hot humbucking pickups and well shielded so not particularly noisy anyway, and it was only ever a real issue at live shows where the whole mix was stupid loud and even then only between songs.

It is at least worth trying some sort of boost or preamp before the interface. You’ll never find one that is perfectly quiet and flat and clean, but there are a lot of options which are plenty good enough. That’ll still only help so much, though.

This is an issue people struggled with before there were amp simulators or even computers, and our options aren’t much better now than the were previously. It’s always a compromise, and we sometimes have to use workarounds. Less gain or noise gate are the two most common solutions. Sometimes if I’m going for heavy distortion anyway, I use crossover distortion, which is basically sample-by-sample gating.

Edit - OK but actually first: Make sure it’s really a real problem! Sometimes we get caught up in little things that seem really big because we’re focused on them, but if we take a couple breaths and step or two back we might see it’s kind of not worth worrying about. In the actual context of the actual mix it might just not be an issue. In some contexts, it can actually be better to have that noise in there because that’s how you know it’s loud!

Last edited by ashcat_lt; 05-11-2022 at 11:06 AM.
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Old 05-11-2022, 07:08 PM   #5
kokconut
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Thank you for all the time you have taken to reply.

I am going to clarify some things as I feel that I'm explaining myself like a closed book(as we say in Spain).


Quote:
Originally Posted by Frank Lee Scarlett View Post
I'm betting that you're using single coil pick-ups?
I'm using humbucker pickups, Seymour Duncan sh-5 in the bridge and sh-2 in the neck of a single cut Dean.


Quote:
Originally Posted by ashcat_lt View Post
I doubt they’re exactly the same result. The passive DI is a step-down transform which reduces the signal level fairly significantly. That requires more gain from the preamp and usually means more noise at the other end. The second rule of gain staging is to try not to turn something down just to turn it up again later. It WILL affect your overall S/N ratio, and if you did some simple tests you could prove it.
What I was trying to say is that I have tried to find out if I would get a better signal from the inbuilt instrument input of the Presonus or by using an external DI box.

With the guitar connected to the DI box, sending the out to one mic input of the Presonus and the through of the DI to one instrument input of the Presonus and adjusting the gain of both inputs to read identical peaks in Reaper, the result is that both signals are identical regarding frequency response, just differing in 0,1 dB of volume due to the not continuous adjustment of the Presonus knobs. But in both cases I'm recording a proper Hi-z signal.


Quote:
Originally Posted by Boogieshoes View Post
You don't say what Amp Sims you are using. That said, many Sims actually model the kind of 'noise' a cranked amp. If also added pedals even as sims in line too, these would add to the noise modelled floor whilst everything is idling.
I use several amp sims, depending of the ocasion and mood. I link below a few examples.


Quote:
Originally Posted by Boogieshoes View Post
It is highly unlikely, if you are using a reasonable audio interface to the PC/Mac that the pre-amps in there are the source of or contributor to the background noise.

Add to that that as soon as you open the guitar volume your pickups will add some noise possibly picking up interference from other electrical kit nearby (computer monitors etc. are a prime source).
Well, down below I attach a rar file with a bunch of recordings to clarify what kind of noise I'm refering to.


As I replied to ashcat, I have recorded a duplicated DI ("DI to mic input" and "DI through..."), you can see and hear that they are basically the same thing. The gain knobs are dialed at eleven o'clock on the interface, just enough gain to record a healthy signal peaking at -6 dB. Any other clip is captured from the mic input.

"Mic input with no cable connected" is a recorded signal of the mic preamp with no cable attached and with the same gain. All we hear is preamp noise.

"Guitar connected with volume closed, then volume full open" is a recorded signal of the whole setup to show if there is any interference between the guitar and other elements. Here I'm holding the guitar as I would do if I were playing, muting the strings with my left hand to not let them ring.

Then you have the several amp sims that I have used in this test. It is simply the "DI to mic" signal reamped in Reaper using the higain channel of every amp sim at default gain and eq, just a quick test. I have used a Marshall 1936V impulse response.

"Full sequence 4s, 4s, 4s..." is just 4 seconds of each recording glued together for an easier comparison of the noise between them.

"Full sequence ... Hybrit" is just the previous one reamped with the Hybrit amp sim to show the difference in noise throught every stage.


As you can see, the preamp alone generates a noticeable noise comparable to that of the guitar connected with no volume or even with the volume full open. This makes me think that the guitar itself isn't a problem as I can't hear any weird noise or interference. Just a little hum at low level with the volume open, but negligible compared to the preamp noise.

Then, on the reamped tracks you can see where the problem is. The very first seconds of noise, prior to play the guitar, can be cut with no problem, even a gate with a threshold of -70 dB or so can mute this noise. But after the last plectrum stroke, as the guitar signal is fading away and losing power, the noise emerges from the depths and kills half of the note tail. I think that I could use a clean note for about 9 seconds. This might seem a lot but, for artistic reasons, this is often very short.

Another thing that I have notice is that the gate cuts the noise at about -70 dB in the first place but with the ringing note the noise is way higher. If I wanted to cut it off closing the gate the threshold should be at around -30 dB.


Now, with all this said, I understand that the caracter and nature of a higain guitar amp is noisy, but I think that this case is excessive. I also use a Blackstar Ht-5 with a Tubescreamer in front of it for home practice when I can make a bit of noise and in this case the notes ring out from full distorsion to a faint blow that you can barely hear, only if you get your ear near to the speaker.



I have uploaded the recorded files to mega, please feel free to download them and take a look. It's only 40 mb.

https://mega.nz/file/YZcXFKYL#BUc_G0...9QY2lP1FzbXzUs
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Old 05-11-2022, 07:15 PM   #6
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Quote:
Originally Posted by Frank Lee Scarlett View Post
I've used a lot of sims and, if I have a noise problem, it's never been the sim's fault.
Oh, yes, you are correct on this. As I said in the first post, I think that the amp sims are not noisy per se.

I think that the problem here is in the signal that is feeding the amp sims. That is what I'm trying to remedy but I don't know how.
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Old 05-12-2022, 03:39 PM   #7
Frank Lee Scarlett
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Depending how hot your signal is, it's possible that the noise is not going to go away. What a lot of people do is use a gate. I personally don't like using a gate on guitar because it's hard to get it just right, especially for a sustained note that decays over time. But you might want to give it a try.
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Old 05-13-2022, 10:53 AM   #8
Boogieshoes
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I am not in a place where I can deal with a rar file to listen to the samples. I will try to look when I am in a position to, but that won’t be for a few days at least. As I am answering you from a mobile device.

The interface pre amp noise (which I can’t hear at the moment) should be minimal, setting a level -6dB is not unreasonable. It will still pickup noise from the devices connected to the input though.

The HyBrit sim will, subject to gain settings, significantly amplify any signal it receives and add its own modelled ‘noise’ if it has some built in to the Sim (some do replicate the amps own noise), much as that of a cranked amp just ticking over. That means ‘any’ noise from the guitar, cables and any pedals positioned in front of the HyBrit will add to that noise all added together.

Humbucker pickups are good at reducing mains power hum and to a degree noise from strip lights etc. but they aren’t a cure all for all sources. If you are using hi gain the amp noise it likely to be appreciably higher and use of a noise gate can help. Tweaking the noise gate for the right threshold to allow guitar sound through and sufficient sustain (release) that it shuts off the noise at the best point for you. Use of a compressor may also help with the sustain thing too.

The trouble with sims is that unlink a cranked amp you don’t get the air movement and a resonance with the guitar and strings that is often used to give the natural sustain.

Sorry I can’t help more right at the moment.
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Old 05-13-2022, 11:30 AM   #9
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Quote:
Originally Posted by Boogieshoes View Post
The trouble with sims is that unlink a cranked amp you don’t get the air movement...
This is slightly OT, but also not a problem with the amp sim itself but rather with the monitoring system. I personally have no trouble getting feedback while playing through amp sims.
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Old 05-14-2022, 06:16 AM   #10
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Originally Posted by ashcat_lt View Post
This is slightly OT, but also not a problem with the amp sim itself but rather with the monitoring system. I personally have no trouble getting feedback while playing through amp sims.
Well appreciate the that went with that…. I personally struggle with SIMs having generally used amps and the having the physical feedback you can get from that through your body and the guitar. Using reasonably good studio monitors as I have whilst sounds may be good I find it hard to adjust to the change in dynamics and touch feedback. Everyone to to their own though, there are many players who use Modellers and Sims in favour of amps.

There are so many things that can also affect the OPs setup and I was drawing , possibly the wrong conclusion from their comments about using the Blackstar and tones vs noise floor. I can’t hear the rar file content and even then I may not have an answer.
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Old 05-14-2022, 08:22 AM   #11
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I see now where you were going there, and it kind of makes sense. My was that if you want it to feel like a loud amp in a room, then you need to make it loud in the room. My studio monitors can just about get there, but it pushes their limits, so I keep a powered PA speaker around for when I really want that extra push.
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