Home » R/E/P » Reason In Audio » DAW & Desks: Is ANYBODY actually still mixing on their desk?
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| Re: DAW & Desks: Is ANYBODY actually still mixing on their desk? [message #82431 is a reply to message #82393 ] |
Wed, 10 August 2005 21:09   |
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 Ronny
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| Extreme Mixing wrote on Wed, 10 August 2005 17:33 |
| Ronny wrote on Tue, 09 August 2005 23:39 |
| TheArchitect wrote on Tue, 09 August 2005 18:01 |
Allow me to restate what I think I have read here. Input levels while recording should be in the -15 to -10 range ballpark on peaks. Ideally, similar levels per track (plus or minus as needed of course) on playback with any needed make up gain on the output bus peaking in the -7 to -5 range to leave room for the mastering process. I'm thinking even those levels may be a little hot if I am comprehending things correctly
I guess I am still a little confused on where the problem actually is occurring, at the A/D conversion coming in or in the summing process in the DAW?
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Not too hot for me. As long as the peak gain isn't above -0dBFs it doesn't matter how high the peak level is, because I'm going to attenuate the input of any processor that will boost gain at output, OTOH when you record peaks at -15dB, mix at -7dB and your material gets mastered, the noise floor of your mics, mic pres and mixing console, is going to be raised by at least -15dB when the ME sets final perceived gain. This may be inaudible on some tracks and not so inaudible on others, for example if you raise the inherent noise of a U87 which is -82dB (cardioid pattern) by 15dB on a vocal track, your final floor will be -67dB, while that's not bad and around the floor of good annie tape, if you record a single coil pickup guitar with a high noise floor amp, typical guitar amp buzz or a guitar DI box or fx processor that is outputting -40 to -30dB of noise due to the cheapo DAC's and the gain gets raised in mastering by +15dB to make up gain, it's going to be quite audible and introduce more noise in your final songs than if you would track close to peak, but without going over. I only track live concert orchestra at -12dB, but for studio work where it's not a get it in one take or else scenario, there isn't any reason to record peak at -15dB, that's too much headroom for some instruments and will raise the noise in your tracks. You don't have to squeeze every bit on the 24 bit A/D conversion that many people used to advise with 16 bit, but the lower your peak gain is at the ADC, the higher the noise floor of the mics and instruments will be raised on the final master.
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Ronny,
I think you have a lot of bad information concerning how the noise floor works in your post. What possible difference does it make if you increase the gain of an 87 or a single coil guitar before the converters of after? The noise floor would stay at the same level in relation to the balance in the mix either way. As long as you have enough bit depth to capture the full signal down to the noise floor, nothing will improve from printing hot.
Steve
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Don't confuse me with some of the digi propeller heads that say you must max the bits at the ADC otherwise you degrade the signal in the digital domain, that's not true peaking at -15dB, my concern of tracking too low at the ADC is entirely analog related. You'll always have enough bit depth to capture down to the noise floor as it's at the LSB. Lets talk noise, record just the hum from a guitar amp, no audio but the noise is there just same when the audio is playing, record it at -15dB peak at the converter, when you turn that track up on mix down or in mastering to just under -0dBFS, you are turning up the noise by +15dB. Now let's record the guitar with it at -15dB peak at the ADC, raise gain by +7dB as was mentioned earlier on mix down, the guitar noise is raised by +7dB, we are now at -8dB peak, the mastering engineer will than raise the -8dB up to -.3dB, but not only that he's going to limit for perceived market levels, the noise floor of the guitar is now going to be raised even more as the RMS level of the material will also be raised, sometimes +8dB more than the original +15dB gain increase on the level of the original guitar hum. Ok, that's on the digital side after the AD conversion and yes as you say, we are raising the keeper material up the same amount of dB's, BUT only until we get to the mastering where setting perceived level keeps the guitar transients low and raises the guitar hum up with the low level notes. There are two sides to this story, the analog and the digital. The analog mic pre or guitar amp in this case, as all analog devices do, operate at an optimal range, so now we we set the recommended input and output on it, noise floor is lowest on that device as we don't have to crank it because the ADC is peaking low and we send that optimal signal to the converter with peaks at -1dB, we don't have to turn up gain, because it's already there, the noise floor doesn't go up. We aren't dealing with noise of the converter which is way lower than the guitar amp or especially digi guitar processors as I mentioned, the noise is in the analog domain, so when you capture at a low digital level, you are going to have to raise gain or you won't have enough level to compete with standard market levels, without bringing the hum up. The key is to optimize every gain structure, but especially on the analog side and anytime you have to raise gain on keeper material rather than lower it, you are raising the noise floor along with it. I don't call a signal too hot in the digital domain when it's below -0dBFs, we are mainly concerned without going over at the ADC.
------Ronny Morris - Digitak Mastering------
---------http://digitakmastering.com---------
----------Powered By Experience-------------
-------------Driven To Perfection---------------
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| Re: DAW & Desks: Is ANYBODY actually still mixing on their desk? [message #82519 is a reply to message #82431 ] |
Thu, 11 August 2005 10:43 |
blairl
Messages: 283
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| Ronny wrote on Wed, 10 August 2005 20:09 |
The analog mic pre or guitar amp in this case, as all analog devices do, operate at an optimal range, so now we we set the recommended input and output on it, noise floor is lowest on that device as we don't have to crank it because the ADC is peaking low and we send that optimal signal to the converter with peaks at -1dB, we don't have to turn up gain, because it's already there, the noise floor doesn't go up.
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(See message #82389 in this thread.)
OK but how do you get the guitar to peak at -1dbfs? Self noise measurements of analog equipment have been taken at standard nominal levels. If in setting your record levels you deviate from these standard measurement settings then the noise floor of analog components like guitar amps and microphones will change as well. If you have set the amp at it's optimal level and you have set the mic pre at it's optimal level (+4dbu=1.23 Vrms) and you have the AD converter calibrated to match the optimal level of the mic pre, (between -20 and -18 dbfs = 0VU), and the guitar player is playing at an average dynamic level, you will naturally be peaking at around -16 to -14dbfs. To peak higher than this you have to turn up the volume somewhere. You would have to raise the gain either at the amp or at the preamp which would change the level at which the self noise measurements were taken and would raise the noise floor of the amp. Raising the gain above optimal levels pre ADC or post ADC would raise the Vrms level and noise level equally. There is no difference. If you were talking about low recording levels being too close to absolute noise floor levels of things such as 16 bit dither or quantization noise then I would understand. Raising the gain of a 16 bit source with low recording levels would be a concern. Not because of the noise level of mics or instruments, but because of the absolute noise floor of a 16 bit source. With 24 bit recording, this is no longer a concern.
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| Re: DAW & Desks: Is ANYBODY actually still mixing on their desk? [message #82569 is a reply to message #82519 ] |
Thu, 11 August 2005 15:05 |
Extreme Mixing
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Ronny,
Sounds like you are agreeing with me to a point. One can easily capture a normal 100 db analog signal within the 144 db range of 24 bit converters. If you leave 15 db of headroom on top, you still have 29 db on the bottom that are not really being used. So once you have captured the whole signal down to it's noise floor, trying to turn it up more is a waste of time, because all of the sound is already there.
Under all circumstances, one should record with as low a noise floor as possible, but once you've done that, I don't see what difference it would make whether you record at -7 or -12. The guitar PART is going to determine where it sits in the mix, and it's noise floor will just be a fact of life. The noise floor does indeed rise when mastering engineers raise the level 15 db by CUTTING OFF THE TOP ALL OF THOSE TRANSIENTS to get the rms level up. Recording it hotter would not change the singal to noise ratio of the tracks at all, because that data has been frozen from the moment the recording was made. I don't think recording hotter would have any impact on the rise in the noise floor after mastering, certainly not the 5 db you are talking about. It just doesn't work that way.
Steve
Steve
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| Re: DAW & Desks: Is ANYBODY actually still mixing on their desk? [message #82571 is a reply to message #82569 ] |
Thu, 11 August 2005 15:17 |
Extreme Mixing
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The main reason to leave headroom while recording tracks is to give yourself some room for creative use of effects during mixing. If you eq a track that is just below clipping, you go over. Same with compression. Who wants to set the compression threshold somewhere between -.5 and -.8 because you recorded so hot? And who wants to waste time and DSP on trims to get the level down? Why not just record it that way and be happy?
I'm pretty sure this is what Paul Frindle is talking about above. I don't think the bits at the top of the scale are any more accurate or musical than the ones that are 8 ro 10 db down. Leave yourself a little room to express yourself later on.
Steve
Steve
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| Re: DAW & Desks: Is ANYBODY actually still mixing on their desk? [message #82580 is a reply to message #82519 ] |
Thu, 11 August 2005 15:58 |
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Ronny
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| blairl wrote on Thu, 11 August 2005 11:43 |
| Ronny wrote on Wed, 10 August 2005 20:09 |
The analog mic pre or guitar amp in this case, as all analog devices do, operate at an optimal range, so now we we set the recommended input and output on it, noise floor is lowest on that device as we don't have to crank it because the ADC is peaking low and we send that optimal signal to the converter with peaks at -1dB, we don't have to turn up gain, because it's already there, the noise floor doesn't go up.
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(See message #82389 in this thread.)
OK but how do you get the guitar to peak at -1dbfs? Self noise measurements of analog equipment have been taken at standard nominal levels. If in setting your record levels you deviate from these standard measurement settings then the noise floor of analog components like guitar amps and microphones will change as well. If you have set the amp at it's optimal level and you have set the mic pre at it's optimal level (+4dbu=1.23 Vrms) and you have the AD converter calibrated to match the optimal level of the mic pre, (between -20 and -18 dbfs = 0VU), and the guitar player is playing at an average dynamic level, you will naturally be peaking at around -16 to -14dbfs. To peak higher than this you have to turn up the volume somewhere. You would have to raise the gain either at the amp or at the preamp which would change the level at which the self noise measurements were taken and would raise the noise floor of the amp. Raising the gain above optimal levels pre ADC or post ADC would raise the Vrms level and noise level equally. There is no difference. If you were talking about low recording levels being too close to absolute noise floor levels of things such as 16 bit dither or quantization noise then I would understand. Raising the gain of a 16 bit source with low recording levels would be a concern. Not because of the noise level of mics or instruments, but because of the absolute noise floor of a 16 bit source. With 24 bit recording, this is no longer a concern.
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Yes, I agree with you that it's less of a concern with 24 bit, but don't leave out the position of the mic and distance from source. That's what typically determines whether inherent mic noise is going to be a factor. The farther away from source, the louder the track has to be pulled up and therefore raising the mic noise and ambient noise along with it. I think you guys are missing my point. Let me explain a problem that I see often. Engineer tracks to the ADC's low -15dB peak meaning the RMS is going to be typically around -30dB to -35dB, mixes low -7dB peak, meaning RMS is going to be -22 to -27dB. They aren't aware of how loud the guitar hum is at these levels, however when the peaks are lowered and the RMS is raised during mastering to -10db or heavier pancake status sometimes only -6dB on some material these days (RMS is going from -30dB to -6dB, an increase of +24dB), the signal to noise ratio becomes a large factor and to get the audio acceptable, marketable, more processing is required to remove the amp noise. Yes, I agree with you that if your analog side is optimized for lowest noise ratio and you come in at -14dBFs, if you record at that level, when you raise gain the keeper content and the noise will rise respectively and there will be no difference "at this time". However, you may be surprised at how many people don't optimize the analog side, are tuned out to noise on guitar amps and processors because they are used to hearing it all of the time, cut the amps wide open and the ADC's way down. The noise does become more profound with the mastering processess and Steve, that's exactly the way it works. I mentioned that it's more important to get the lowest noise floor going in, if it means running the ADC's at -15dBFs that's fine, but it's not always necessary. If you record a guitar using a DM2000 for front end, optimize the amp and it's -16dBFs, you can turn the mic pre's up to peak at -1dB with no degradation, because they are designed to output the signal at -0dBFs. You are than hearing the loudest that the noise floor will be until it goes to mastering. There are different congfigurations and nothing is written in stone, but please understand what I'm relating here, this isn't bad information, it's what I have to deal with on a daily basis.
------Ronny Morris - Digitak Mastering------
---------http://digitakmastering.com---------
----------Powered By Experience-------------
-------------Driven To Perfection---------------
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| Re: DAW & Desks: Is ANYBODY actually still mixing on their desk? [message #82607 is a reply to message #82580 ] |
Thu, 11 August 2005 18:04 |
blairl
Messages: 283
Registered: April 2004 |
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| Ronny wrote on Thu, 11 August 2005 14:58 |
I think you guys are missing my point.
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I think that perhaps we are not understanding each other.
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...you may be surprised at how many people don't optimize the analog side...
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Absolutely, this is a problem.
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If you record a guitar using a DM2000 for front end, optimize the amp and it's -16dBFs, you can turn the mic pre's up to peak at -1dB with no degradation, because they are designed to output the signal at -0dBFs.
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I think this statement is where we are not understanding each other. They way I see it is that when the signal to noise ratio of analog equipment is measured, it is done according to a standard where all analog equipment used to measure the noise is set to +4dbu. If you turn the mic pre up beyond +4dbu at this point to make the ADC peak at -1db you have thrown out the standard and when you bring the mic pre up you are bringing up the noise floor of the guitar amp with it. Whether you bring the guitar amp level up before the ADC with the mic pre or you bring it up after the ADC digitally, it is the same. The noise floor of the guitar amp that was properly optimized for noise is not the problem when it comes to bringing the level up in mastering. It is the noise floor of the 16 bit or 24 bit recording that could be an issue. Again to clarify. Boosting the level beyond +4db with a mic preamp to make it peak at -1dbfs at the ADC will bring up the noise of the guitar amp exactly the same amount as if you were to leave the mic pre at +4db, having the ADC peak at around -14dbfs and then boosting the level digitally after the ADC to peak at -1dbfs, either in mixing or mastering.
Try an experiment to verify this. Set up a guitar amp and optimize the levels. Set your mic pre so that the the ADC is peaking around -14 dbfs with someone playing guitar. Record the ambient noise with nobody playing. Now boost the level digitally +13 db and look at the noise floor on your meters. Make a note. Now go back and set your mic pre to peak at -1dbfs while somebody is playing guitar. Record the ambient noise with nobody playing. Look at the noise floor on your digital meters. If the guitar player was playing the at the same dynamic level when you set the different levels then the noise floor of the guitar amp will be the same in both cases.
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| Re: DAW & Desks: Is ANYBODY actually still mixing on their desk? [message #82614 is a reply to message #82607 ] |
Thu, 11 August 2005 18:45 |
Extreme Mixing
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Thank you, Blair,
That's the same point I was trying to make. The signal to noise ratio would not change, and the result is the same whether you do it inside the computer or at the preamp. It's the same!!!
Further, I would think that peak limiting at mastering would have little effect on the rms ratio of signal to noise on the master, since both would go up by THE SAME AMOUNT. There aren't too many transients in the noise floor. But hey, I'm more offended by the notion of categorically whacking 15db of REAL MUSIC off the top of my record. If someone thinks that's a wonderful difference, then I don't find it surprising that they forget to adjust the volume before comparing noise at the beginning of the track...
Steve
Steve
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| Re: DAW & Desks: Is ANYBODY actually still mixing on their desk? [message #82665 is a reply to message #82607 ] |
Fri, 12 August 2005 01:41 |
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Ronny
Messages: 2739
Registered: April 2004
Location: Brunswick, Georgia |
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| blairl wrote on Thu, 11 August 2005 19:04 |
| Ronny wrote on Thu, 11 August 2005 14:58 |
I think you guys are missing my point.
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I think that perhaps we are not understanding each other.
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...you may be surprised at how many people don't optimize the analog side...
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Absolutely, this is a problem.
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If you record a guitar using a DM2000 for front end, optimize the amp and it's -16dBFs, you can turn the mic pre's up to peak at -1dB with no degradation, because they are designed to output the signal at -0dBFs.
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I think this statement is where we are not understanding each other. They way I see it is that when the signal to noise ratio of analog equipment is measured, it is done according to a standard where all analog equipment used to measure the noise is set to +4dbu. If you turn the mic pre up beyond +4dbu at this point to make the ADC peak at -1db you have thrown out the standard and when you bring the mic pre up you are bringing up the noise floor of the guitar amp with it. Whether you bring the guitar amp level up before the ADC with the mic pre or you bring it up after the ADC digitally, it is the same. The noise floor of the guitar amp that was properly optimized for noise is not the problem when it comes to bringing the level up in mastering. It is the noise floor of the 16 bit or 24 bit recording that could be an issue. Again to clarify. Boosting the level beyond +4db with a mic preamp to make it peak at -1dbfs at the ADC will bring up the noise of the guitar amp exactly the same amount as if you were to leave the mic pre at +4db, having the ADC peak at around -14dbfs and then boosting the level digitally after the ADC to peak at -1dbfs, either in mixing or mastering.
Try an experiment to verify this. Set up a guitar amp and optimize the levels. Set your mic pre so that the the ADC is peaking around -14 dbfs with someone playing guitar. Record the ambient noise with nobody playing. Now boost the level digitally +13 db and look at the noise floor on your meters. Make a note. Now go back and set your mic pre to peak at -1dbfs while somebody is playing guitar. Record the ambient noise with nobody playing. Look at the noise floor on your digital meters. If the guitar player was playing the at the same dynamic level when you set the different levels then the noise floor of the guitar amp will be the same in both cases.
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I'm not arguing that point Blair, I'm telling you that the mastering process is going to raise the noise floor and if you want to record most effectively, be aware that the level you hear guitar buzz at on the mix down is going to go up in the mastering, it's that simple. I don't have to run your tests, I deal with this every day and you are correct, but you are still missing my point and that is you should be aware of how much the noise is going to be accenuated during the mastering process. As I said before and will repeat for the third time, the noise ratio will be the same regardless until it goes to mastering and the transient peaks are lowered and the RMS is raised bringing the guitar hum up with it and the loud guitar notes down. BTW, not all guitar amps sound best at +4dB output, there are some euphonic benefits for going above +4dB and this is only sensitivity, 'not the end of your headroom' which in the analog world and on my big annie board goes up to +30dBu. On the DM2000, +4dBu is actually closer to -20dBFs. It's often impossible to output recommended gain on all devices, rather than totally compromising one devices recommendations, it's often better to fudge a little on all of the devices.
For an audible example of what I'm talking about, go to my website, on the vertical column of sound clips, second one down that says: "Shows noise reduction on a typical guitar intro. Noise is coming from a guitar fx processor" The noise is coming from a Digitech RP100 guitar processor and noise floor on this song premastered was -30dB. If you hear the before clip and the noise doesn't bother you or you can't hear any improvement, than disregard what I've been saying, but don't tag me with spreading misinformation on these newsgroups, I dedicate too much of my time trying to help people get the cleanest sounding mixes and this is valuable information if you understand where I'm coming from and apply it to your mixing styles in the future.
------Ronny Morris - Digitak Mastering------
---------http://digitakmastering.com---------
----------Powered By Experience-------------
-------------Driven To Perfection---------------
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| Re: DAW & Desks: Is ANYBODY actually still mixing on their desk? [message #82732 is a reply to message #82665 ] |
Fri, 12 August 2005 09:57 |
Extreme Mixing
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Ronny,
I agree that sounds should always be recorded with as little noise as possible. What I don't agree with is your statement that recording the guitar hotter in your example above, would have made any difference in the signal to noise ratio. Both the guitar and the noise would be louder. The point is that you have to do something to push the noise floor lower in relation to the guitar. Simply cranking the output of the mic pre won't do that. You have to change the pedal, examine the ground issues, eliminate RF--do something, but just printing hotter will not advance the cause at all.
Steve
Steve
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| Re: DAW & Desks: Is ANYBODY actually still mixing on their desk? [message #82744 is a reply to message #82732 ] |
Fri, 12 August 2005 10:37 |
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Ronny
Messages: 2739
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Location: Brunswick, Georgia |
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| Extreme Mixing wrote on Fri, 12 August 2005 10:57 |
Ronny,
I agree that sounds should always be recorded with as little noise as possible. What I don't agree with is your statement that recording the guitar hotter in your example above, would have made any difference in the signal to noise ratio. Both the guitar and the noise would be louder. The point is that you have to do something to push the noise floor lower in relation to the guitar. Simply cranking the output of the mic pre won't do that. You have to change the pedal, examine the ground issues, eliminate RF--do something, but just printing hotter will not advance the cause at all.
Steve
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You and Blair are both correct, however the fellow that started the thread said that he was peaking at -15dB and sending mixes to the ME at -7dB and was asking if these levels were correct, as I mentioned nothing is written in stone, but we all agree that opimizing every gain stage or at least as close as you can get will give the best results and my advice still stands that he doesn't need to give himself that much headroom. He needs to hear how loud the guitar noise is in that example and be aware that it's going to increase per ratio of guitar note gain on the final master. Absolutely the best solution is to take care of noise at the source. Speaking of single coil guitar hum, you can often eliminate that by either getting out of the EMI field from the amp, which extends about 4 feet out the front and back of the amp in an elliptical pattern that looks much like the magnetic flux lines when you put filings on a bar magnet in science class. If the room is too small to do this, the guitarist can turn the neck of the guitar 90 degrees perpendicular to the amp face and reduce the hum by mucho decibels, because the guitar strings are basically antennae that pick up the field, run the neck parallel along the flux lines and you'll hear an immediate improvement in signal to noise ratio. It all starts in the tracking doesn't it.
------Ronny Morris - Digitak Mastering------
---------http://digitakmastering.com---------
----------Powered By Experience-------------
-------------Driven To Perfection---------------
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| Re: DAW & Desks: Is ANYBODY actually still mixing on their desk? [message #82802 is a reply to message #82744 ] |
Fri, 12 August 2005 18:51 |
Paul Frindle
Messages: 372
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| Ronny wrote on Fri, 12 August 2005 16:37 |
| Extreme Mixing wrote on Fri, 12 August 2005 10:57 |
Ronny,
I agree that sounds should always be recorded with as little noise as possible. What I don't agree with is your statement that recording the guitar hotter in your example above, would have made any difference in the signal to noise ratio. Both the guitar and the noise would be louder. The point is that you have to do something to push the noise floor lower in relation to the guitar. Simply cranking the output of the mic pre won't do that. You have to change the pedal, examine the ground issues, eliminate RF--do something, but just printing hotter will not advance the cause at all.
Steve
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You and Blair are both correct, however the fellow that started the thread said that he was peaking at -15dB and sending mixes to the ME at -7dB and was asking if these levels were correct, as I mentioned nothing is written in stone, but we all agree that opimizing every gain stage or at least as close as you can get will give the best results and my advice still stands that he doesn't need to give himself that much headroom. He needs to hear how loud the guitar noise is in that example and be aware that it's going to increase per ratio of guitar note gain on the final master. Absolutely the best solution is to take care of noise at the source. Speaking of single coil guitar hum, you can often eliminate that by either getting out of the EMI field from the amp, which extends about 4 feet out the front and back of the amp in an elliptical pattern that looks much like the magnetic flux lines when you put filings on a bar magnet in science class. If the room is too small to do this, the guitarist can turn the neck of the guitar 90 degrees perpendicular to the amp face and reduce the hum by mucho decibels, because the guitar strings are basically antennae that pick up the field, run the neck parallel along the flux lines and you'll hear an immediate improvement in signal to noise ratio. It all starts in the tracking doesn't it.
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I have been though this discussion before (not least of all when doing the input stages of the R3) it's a headache to work through because of different perceptions of what constitutes levels within the analogue and digital domains - of course they are the same and IMLE the best way to illustrate this is in terms of dynamic ranges.
In this case we need to think of dynamic range as the difference between the noise and the max signal modulation.
For the Guitar amp this is the noise and hum versus the sound pressure produced when the guy plays. If we assume this to be 80dB for argument:
We then have the Mic which is almost certainly miles better than the amp - producing a signal level that easily stretches comfortably between the hum and noise of the amp and the level of the guitar playing - so probably very little loss of dynamic range here - we still have 79dB or so.
We then hit the converter - the converter has a dynamic range of say 110dBr in the digital domain - so in order to avoid introducing excessive converter noise we must modulate it to at least -30dBr or so. So in this case there's plenty to play with and you can get it badly wrong without any damage (even modulating at -20dB or less) cos the source has such a restricted dynamic range. But if we actually modulate the converter optimally so that the guy playing hard gets nearly full level out of the converter, the dynamic range of the track is still around 79dBr - in the digital domain within the mixer.
Now almost whatever you do within reason with gains in the mixer this will remain unchanged, since increasing it will make it clip immediately - and you can reduce it by as much as 60dB (and bump it back up again) without hitting the 24bit noise floor of the system.
So (apart from deliberately using EQ to boost the line hum freqs) the only thing you can practically do to DECREASE the dynamic range of that signal (i.e. make the amp hum and noise proportionally louder wrt to the guy playing) is to compress or limit it - i.e. dynamically make the soft bits louder and/or the loud bits softer. A compressor/limiter reduces dynamic range by definition - and that's why the hum may get louder in the mastering stages, as the guy struggles to achieve 'commercially acceptable' levels of 'fashionably continuous' modulation.
So if the mastering guy put on (for an unreasonable illustration) say 20dBs of total compression - if the guitar was a solo instrument peaking flat out and there was no other music or significant noise in the track, when the guy stops playing the amp noise will wander up from -79dB to -59dBr, i.e. change from being just acceptable to annoyingly loud. BTW, obviously this would also occur if you put this much compression on the track within the mixer.
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| Re: DAW & Desks: Is ANYBODY actually still mixing on their desk? [message #82811 is a reply to message #82802 ] |
Fri, 12 August 2005 20:41 |
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Ronny
Messages: 2739
Registered: April 2004
Location: Brunswick, Georgia |
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| Paul Frindle wrote on Fri, 12 August 2005 19:51 |
| Ronny wrote on Fri, 12 August 2005 16:37 |
| Extreme Mixing wrote on Fri, 12 August 2005 10:57 |
Ronny,
I agree that sounds should always be recorded with as little noise as possible. What I don't agree with is your statement that recording the guitar hotter in your example above, would have made any difference in the signal to noise ratio. Both the guitar and the noise would be louder. The point is that you have to do something to push the noise floor lower in relation to the guitar. Simply cranking the output of the mic pre won't do that. You have to change the pedal, examine the ground issues, eliminate RF--do something, but just printing hotter will not advance the cause at all.
Steve
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You and Blair are both correct, however the fellow that started the thread said that he was peaking at -15dB and sending mixes to the ME at -7dB and was asking if these levels were correct, as I mentioned nothing is written in stone, but we all agree that opimizing every gain stage or at least as close as you can get will give the best results and my advice still stands that he doesn't need to give himself that much headroom. He needs to hear how loud the guitar noise is in that example and be aware that it's going to increase per ratio of guitar note gain on the final master. Absolutely the best solution is to take care of noise at the source. Speaking of single coil guitar hum, you can often eliminate that by either getting out of the EMI field from the amp, which extends about 4 feet out the front and back of the amp in an elliptical pattern that looks much like the magnetic flux lines when you put filings on a bar magnet in science class. If the room is too small to do this, the guitarist can turn the neck of the guitar 90 degrees perpendicular to the amp face and reduce the hum by mucho decibels, because the guitar strings are basically antennae that pick up the field, run the neck parallel along the flux lines and you'll hear an immediate improvement in signal to noise ratio. It all starts in the tracking doesn't it.
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I have been though this discussion before (not least of all when doing the input stages of the R3) it's a headache to work through because of different perceptions of what constitutes levels within the analogue and digital domains - of course they are the same and IMLE the best way to illustrate this is in terms of dynamic ranges.
In this case we need to think of dynamic range as the difference between the noise and the max signal modulation.
For the Guitar amp this is the noise and hum versus the sound pressure produced when the guy plays. If we assume this to be 80dB for argument:
We then have the Mic which is almost certainly miles better than the amp - producing a signal level that easily stretches comfortably between the hum and noise of the amp and the level of the guitar playing - so probably very little loss of dynamic range here - we still have 79dB or so.
We then hit the converter - the converter has a dynamic range of say 110dBr in the digital domain - so in order to avoid introducing excessive converter noise we must modulate it to at least -30dBr or so. So in this case there's plenty to play with and you can get it badly wrong without any damage (even modulating at -20dB or less) cos the source has such a restricted dynamic range. But if we actually modulate the converter optimally so that the guy playing hard gets nearly full level out of the converter, the dynamic range of the track is still around 79dBr - in the digital domain within the mixer.
Now almost whatever you do within reason with gains in the mixer this will remain unchanged, since increasing it will make it clip immediately - and you can reduce it by as much as 60dB (and bump it back up again) without hitting the 24bit noise floor of the system.
So (apart from deliberately using EQ to boost the line hum freqs) the only thing you can practically do to DECREASE the dynamic range of that signal (i.e. make the amp hum and noise proportionally louder wrt to the guy playing) is to compress or limit it - i.e. dynamically make the soft bits louder and/or the loud bits softer. A compressor/limiter reduces dynamic range by definition - and that's why the hum may get louder in the mastering stages, as the guy struggles to achieve 'commercially acceptable' levels of 'fashionably continuous' modulation.
So if the mastering guy put on (for an unreasonable illustration) say 20dBs of total compression - if the guitar was a solo instrument peaking flat out and there was no other music or significant noise in the track, when the guy stops playing the amp noise will wander up from -79dB to -59dBr, i.e. change from being just acceptable to annoyingly loud. BTW, obviously this would also occur if you put this much compression on the track within the mixer.
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Exactly. -79dB from a guitar amp is very, very good, though, you are talking as low or lower noise floor than good 2 inch tape. Even at -59dB, not a big problem and no need to denoise, BUT, many guitar tracks come in much louder, -30dB isn't rare, that's measured noise without the guitar playing but with volume knobs all the way up. Even direct guitar recorded through POD's and other type guitar fx processors with no amp or mic in the equation can exhibit -30dB noise floor, before mastering processes are performed. The problem with those devices are the DAC's, let's face it, you ain't gonna get a decent converter on a 100 to 300 dollar guitar pedalboard or processor. Distortion/overdrive/dirty type patches are prime candidates for outputting high noise, especially when the guitarist isn't using the noise reduction correctly, that's available at the end of most dirty patch chains, couple that with a single coil pu guitar with the performer playing in the EMI field and you may able to see my concern. The guitar processors with the digi outs have a night and day difference with regard to noise when you bypass the DAC's.
WRT, the noise in between riffs, rhythm patterns or progressions, not a problem there as a proper set gate will eliminate the noise when the guitar isn't playing. Gates only come on when the signal falls to the threshold though and aren't effective at all when the guitar is playing notes, so although you can totally eliminate the hum when the guitar is resting, the noise is totally back when the signal rises above the threshold setting. The noisy guitar intro that I mentioned earlier came from a US band that was seeking a record deal with a Swedish label, the label complained about the noise said it wasn't acceptable, their manager hired me to denoise the tracks and remix the songs, they were accepted after that. I couldn't possibly tell you what the level of noise is deemed acceptable as all people are different, but I get a lot of material in that has noisier guitars than the one on those tracks and it takes longer to master tunes with high noise floor. It's also mighty hard to match the tone on a guitar that was tracked optimally when you have to pull out noise freq's, so the best results come from the engineers that know how to get the lowest noise on all of their tracks, it's one factor that separates the men from the boys, IMHO.
------Ronny Morris - Digitak Mastering------
---------http://digitakmastering.com---------
----------Powered By Experience-------------
-------------Driven To Perfection---------------
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| Re: DAW & Desks: Is ANYBODY actually still mixing on their desk? [message #82834 is a reply to message #82811 ] |
Sat, 13 August 2005 00:47 |
Extreme Mixing
Messages: 715
Registered: April 2004
Location: Los Angeles, CA |
Gold Member |
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So if I follow you correctly in your example, Paul, it is the compressor pulling the noise floor up by 20 db, Printing the guitar part hotter, or closer to full scale would not change the outcome on the noise at all, because the guitar is going to sit where it needs to in the mix, and it will be hit by the compressor with the same result either way. That was really my only point of disagreement with Ronny. Thanks for putting the science in a way that makes it easy to follow the facts.
Steve
Steve
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| Re: DAW & Desks: Is ANYBODY actually still mixing on their desk? [message #82840 is a reply to message #82834 ] |
Sat, 13 August 2005 02:11 |
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Ronny
Messages: 2739
Registered: April 2004
Location: Brunswick, Georgia |
Platinum Member |
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| Extreme Mixing wrote on Sat, 13 August 2005 01:47 |
So if I follow you correctly in your example, Paul, it is the compressor pulling the noise floor up by 20 db, Printing the guitar part hotter, or closer to full scale would not change the outcome on the noise at all, because the guitar is going to sit where it needs to in the mix, and it will be hit by the compressor with the same result either way. That was really my only point of disagreement with Ronny. Thanks for putting the science in a way that makes it easy to follow the facts.
Steve
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Steve, here is the first post that I wrote on this thread:
You don't have to squeeze every bit out of 24 bit, you have plenty of footroom. You'll never get -144db until you are fully into the digital realm and that will only be on digital black or dead air in between track sections where no noise floor of the tracking gear is present, because the best ADC's are now only getting -120dB. Not all music genres allow peaks set at -3dB, especially orchestra, because it doesn't matter if the conductor plays the loudest passage at soundcheck, the performance when the audience is there almost always comes out louder when the performers are in the heat and excitement of the live concert. It's by far better to make up gain in the digital realm, than having even one over at the ADC. If there isn't a repeatable passage to copy and paste from, it can render a whole performance unusable. Let's say you set peak at -12dB instead of -3dB and unexpected transients give you an actual peak level of -5dB. That would be +4dB into digital distortion if we set -3dB peak. Ok, you raise level by +5dB to make up the gain once in the digital realm. Your ADC is now giving -115dB instead of -120dB. No one is going to hear the difference between the same type ADC inputting at -120dB and inputting at -115dB, because the noise floor of the amplifier going to monitors is going to be around -105dB or often lower, well above the converters self noise when set to -12dB peak.
Record the same piece at -3dB via some good ADC's and mirror simultaneously to other tracks at -12dB, going 24 bit. Raise gain on the -12dB example by +9dB to match the -3dB peak tracks, once you are playing back in the digital realm and run a seemless A/B, between the two examples, I guarantee you that you will not hear a difference if you are using good quality mics and ADC's.
Than I think what confused you was this: In relation to the question about what gain to send to mastering.
I said this:
Not too hot for me. As long as the peak gain isn't above -0dBFs it doesn't matter how high the peak level is, because I'm going to attenuate the input of any processor that will boost gain at output, OTOH when you record peaks at -15dB, mix at -7dB and your material gets mastered, the noise floor of your mics, mic pres and mixing console, is going to be raised by at least -15dB when the ME sets final perceived gain. This may be inaudible on some tracks and not so inaudible on others, for example if you raise the inherent noise of a U87 which is -82dB (cardioid pattern) by 15dB on a vocal track, your final floor will be -67dB, while that's not bad and around the floor of good annie tape, if you record a single coil pickup guitar with a high noise floor amp, typical guitar amp buzz or a guitar DI box or fx processor that is outputting -40 to -30dB of noise due to the cheapo DAC's and the gain gets raised in mastering by +15dB to make up gain, it's going to be quite audible and introduce more noise in your final songs than if you would track close to peak, but without going over. I only track live concert orchestra at -12dB, but for studio work where it's not a get it in one take or else scenario, there isn't any reason to record peak at -15dB, that's too much headroom for some instruments and will raise the noise in your tracks. You don't have to squeeze every bit on the 24 bit A/D conversion that many people used to advise with 16 bit, but the lower your peak gain is at the ADC, the higher the noise floor of the mics and instruments will be raised on the final master.
When you make up gain, the noise floor is going to go up and be "more audible". No where did I say that the noise floor is going to be raised at a higher ratio if you track lower, nor did I say that you will get less noise floor by tracking hotter. You seem to already understand that when it goes to mastering and perceived leveling is performed that the noise does go up in relation to the keeper notes due to the decreasing gain on peak transients and the increasing gain on low levels. What I'm saying above is, if you track and mix low, you won't "hear" the guitar hum or noise floor on the other tracks as loud as it's going to be when the ME performs his processing. I see what threw you off, but this is what I'm saying. Dynamic range will be less on the final master, the guitar hum will be louder relative to the loud guitar notes, it makes little difference if you peak at -15dB on tracking and mixing at -7dB, except for the fact that your noise floor is going to be "audibly" lower and the hum will not be as noticeable as it's going to be on the final master. You can take care of the noise on the tracking, or you can pay the ME extra for denoising, but to get a commercially viable product, it has to have a noise floor relative to typical commercial songs. I have 5,000 members on my newsgroups that I've been teaching mixing to over the internet for the past 10 years. Most are home recordists, a few commercial engineers that give me a hand and a fair share of intermediate level recordists. I get a lot of mastering work from these folks, one of the biggest differences that I hear between the home recordist mixes and the commercial ones, is noise on the tracks. Do not think that you have to give every ME +7dB of headroom, mix your songs with enough gain to hear how much the noise floor is going to be on the final product or at least be aware that noise floor goes up in mastering when RMS levels are raised and peak transients are lowered. Nip the noise on the tracking.
Let's try this again:
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Ronny,
I think you have a lot of bad information concerning how the noise floor works in your post. What possible difference does it make if you increase the gain of an 87 or a single coil guitar before the converters of after? The noise floor would stay at the same level in relation to the balance in the mix either way. As long as you have enough bit depth to capture the full signal down to the noise floor, nothing will improve from printing hot.
Steve
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That's correct except for the bad information part, but you aren't fully understanding what I'm saying as the ratio between the noise and the keeper notes narrows during mastering processing, not saying that it narrows when you track hotter at the ADC and mix low, only that the noise isn't heard as loud, but will be more profound after mastering. Hopefully I've cleared it up for you with this post.
------Ronny Morris - Digitak Mastering------
---------http://digitakmastering.com---------
----------Powered By Experience-------------
-------------Driven To Perfection---------------
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