Finding your channel has been a game changer for me in many ways but you solved my problem for not only proper DI recording levels but also for re-amping and being able to match the levels in out of the recording desk to what my guitar was sending to the amp in the same chain. Your multimeter method and using the DAW signal generator is so precise and there is no guesswork or having to match sounds by ear at all. I took it a step further and recorded the DAW signal out of the reamp box and into my loop pedal. I could then set the loop pedal level to output 500mV and then sent that into my DAW and back again through the reamp box and just adjusted my reamp box to get the signal back up to the 500mV. I now have a perfectly level matched direct guitar, DI and Reamp chain. Interesting when it came to re-amping I had to push my presonus studiolive preamp for the DI to 8db gain so that the signal coming back out of the DAW and through my reamp box could be matched back to the 500mV going into the DI. If I set the preamp to zero db the reamp signal could not get boosted back up to the 500mV level that went into the DI. Probably a quirk with my reamp box. Anyway your mutlimeter method also helped me to test my signal levels out of my effects switcher and confirmed why I always found my guitar plugged direct into my amp sounded brighter than when I sent my guitar signal via my buffered effects switcher into the same amp. It was doing my head in trying to work out why this was happening. All solved now. I have quite a complex set up with multiple amp heads being controlled by an amp switcher. My guitar pedals are being routed to my amp switcher via an effects switcher. Using your multimeter method I found that the signal out of my effects switcher being sent to my amp switcher was lower in mV than the guitar signal going into the effects switcher. The awesome thing was I was able to add a transparent gain boost into the chain to bring the level back up. And just like that the guitar plugged direct into amp and the guitar into amp via the effects switcher is sounding identical. A huge frustration solved and it was just a slight signal level drop that was causing it. Without the multimeter and using a consistent reference tone signal I could never have solved this mystery. Anyway thanks for the great suggestions which have helped me immensely.
Love reading this! Exactly the kind of situation where this stuff matters and it makes it very easy to understand which pieces of gear and do what to the signal. And when it’s set up - you never have to worry about it again, it just WORKS. Well done 👏
@@eds4754 For sure. It's great not having to 2nd guess anything when you know your signal chain is consistent. And there is no way your ears can ever guide the required gain adjustments needed compared to the multimeter. Especially with the complex way that tones can change in a guitar rig as signal levels fluctuate.
Objectively the best/cleanest way is to optimize SNR of analog domain and ADC, then adjust the level digitally pre-ampsim. Does this matter when talking about extremely noisy guitar pickups? Not really, but this is still an important thing to keep in mind. You are getting worse SNR by doing what you do, just that it doesn't really matter in this particular scenario. I predict so many people getting utterly confused about this. 🤣
Yeah I think the thing is how much of an issue is it going to be and what scenarios? The majority of users are probably already using around 12dBu or less headroom so probably are on the hotter end anyway. It would take maybe recording guitars 20dB too quiet on noisy old converters and a high gain amp to even notice. But yeah, stepped gain makes it easy to optimise a good level and easily have something that can be calibrated for various plugins easily. I’m not sure most situations with SNR are worth worrying about, but obviously if it’s presenting an issue there are ways to deal with it.
@@eds4754 Absolutely. I just work as an audio engineer and decided to throw in a comment since these things can cause incredible amount of confusion for those who are not truly familiar with what this all actually means. You know, "some guy said to always record at zero gain because noise doesn't matter". Then this morphs into a some sort of universal mystical truth, and it ultimately leads to me having some noisy drum tracks to mix because "we were clever and did the right thing while recording!". 🤣 That being said, one thing I do hope for is that plugin manufacturers would start to offer better information about these kind of things. I mean the "best practice" of recording at healthy levels to maximize SNR isn't that great in this context if this means you feed your ampsim ~10dB too hot. Manufacturers should offer some kind of tools for a user to correctly a) identify that this can be an issue (i.e. level matters), and b) how to set their input gain correctly within a plugin (at least roughly). I mean I don't expect a regular Joe to understand how their interface's preamp actually works, or how their AD/DA translates voltage values between analog and digital dBFS, or that any of this has anything to do with their guitar sound. No, a plugin should inform user clearly about levels in one form or another (i.e. what is the reference level for a "correct" amp behavior).
@@knzznk3507 I totally agree! The main issues are people doing things without really understanding why they’re doing it, and also, the lack of information from plugin manufacturers, which there really is no excuse for - their assumption is everyone is too dumb to understand and that just achieves nothing.
the main reason I made this video is because of the amount of replies to my other videos about “what about SNR?!” and it’s really to show that there is often other stuff that may be more of a concern.
Didn't think about that, but it does make sense that the noise floor of the pickups is much higher than the interface. And I guess at least in 24 bit quantization is also a non issue. That leaves the smaller wave forms (depending on the DAW) as the only real annoyance when recording guitar at minimum gain I guess. Thanks for sharing. :)
Ha yep. But all DAW's have the ability to zoom in on the waveform, so just use that if you need to see things more clearly. There are often other waveform views that can show different kinds of information about your signal. Its actually quite hard to record a DI signal that is too quiet, most gear at their lowest levels will produce a healthy signal.
Surely the solution is to track the Dis hot, with the most efficient signal to noise ratio, and then turn down the input gain on the plug in, as to feed it the ideal signal. That way having a dynamic and clean signal with a low noise floor but still feeding into the amp at an ideal level, that reflects the amps sound accurately.
Of course. I’m just demonstrating what the actual real world benefits are. What conclusion can you draw from the video? Does a higher input level produce less noise? What is the highest source of noise in the recording chain?
@@eds4754 I'd guess that due to the nature of analog to digital conversion, that higher input gain is the way to go, as to have a cleaner signal. I'd think that it would then be ideal to turn down the input in the plug in or DAW. Which unfortunately is a massive hassle. I just want to plug my guitar into a plug in and get great tones without having to worry
conductive paint or copper inside the cavities and around the body of the guitar behind the pickups, make sure the wiring is done well with good components etc. Make sure that you connect the shielding to ground otherwise it won’t work. Always touching the strings or somewhere metal on the guitar while you play also helps. You can also check for things in the room that may cause noise and find areas (and even angles to point the guitar) where noise is quietest. A good guitar tech should be able to ground your guitar properly if you need help.
also make sure you are using the correct cables, and hi z input (or di box) with a suitable impedance. and also things like laptop charges can add noise so try to find the cause of any problems be removing them one by one and seeing what effect they have
I was trying to match noise level of Golde Age preamp and noise level of pickups on my guitar to find perfect recording level,becouse noise flor of preamp stays the same if you turn it down,so i had to find optimal level for recording,and ofcourse to find the perfect position where noise is lowest.
thats true thanks for doing this, it seems that all of us are having that RF shit over the tracks, but its true moving or keep you far from your pc or monitors helps, signal to noise ratio doesnt affect the noise level as you show here, but maybe using a real mic could be different?
It’s all about minimising what gets into the pickups really, there’s usually a spot in the room where you can angle the pickups and the noise will be quieter. Also touching a metal part of the guitar and making sure the shielding is grounding gets it down. The noise going into the amp would be no different, but amps are much noisier than recording DI’s because valves and analog gear has a much higher noisefloor
I am keen to know how you would approach getting input levels for tonex calibrated? It seems due to IKs less than stellar software I basically have to tweak my presets in their plug in or standalone app and then transfer the preset to the pedal. Regarding the app I haven't seen Tonex mentioned in your reference level specs like you do with other amp sims. What reference level would you say is the most appropriate for the tonex factory presets to sound accurate? Do you also use the Tonex pedal? If so how do you approach calibrating the input level into the pedal so that the app and the pedal are aligned in terms of preset sounds? I assume it is not the same as calibrating a guitar reamp chain and the tonex pedal probably wants a higher input level to what the guitar is putting out and a level that is different to what I am sending into the app via my DI. I guess I could do it by ear but it would be great if there was a way to measure the signal chain and get it all more accurate like you do with your multimeter for your DI and reamp levels. The IK stuff sounds great but the implementation of their pedals and software could be done so much better.
For tonex, the input level depends on the reamp level used to create each model. So each “creator” is essentially like their own plugin developer with their own dBu specs, rather than there being one consistent level. Furthermore, IK don’t provide any guidance or recommendations for levels for their own or anyone else’s models and even their own interfaces and reamp boxes have totally different specs and would yield different results. I have no idea what level they use for their models, I genuinely can’t seem to make them sound good no matter what. I don’t have the pedal but I think when it’s set to 0 on the input gain it’s about 8dBu IIRC. You can measure it by using the device as an interface and recording a 0.775V sine wave through it and seeing what dBFS level you get. Had IK implemented this properly, each users input level could be embedded into each capture and the software could automatically adjust so it’s correct for every user for every guitar. It’s a mess of IK’s making and unfortunately asking them for any more information or help just leads to silence. I agree they make some cool tech, but other aspects of the company let them down completely. Tonocracy tried to remedy these input level issues in their software which imo is a little more accurate than tonex too (but not quite as accurate as NAM).
Thanks for the quick reply. Appreciate it. I think IK are happy for the general users business who don't understand or don't care about this stuff but eventually people will grow to hate their tones and the number of negative posts will start to grow. I guess the smart people selling their own tonex captures should at least provide some guidance to their customers on their captures if they want good reviews and more sales.
@@TheBukmanYeah I agree. IMO if someone is selling captures they should provide this information so users have the means to achieving the most accurate tone if they desire. If this value isn’t known then it really doesn’t give customers the chance to hear the amp in its original form, as it was dialled in prior to capturing. Generally it leads to a lot of redundant models and processing, and just clutter because so many models end up sounding similar EXCEPT for the input levels. Ah well.
Does this essentially mean it's pointless to use a DI with an amp sim? What about the conversion of an unbalanced to balanced signal? Highly appreciate you work, by the way!
No, you need a DI box (or instrument input) to handle the impedance mismatch between a guitar and line input. You can use an instrument input on an interface or an external DI box, just aim for one with a minimum of 1M Ω impedance so it presents a high enough load to the pickups
12-15dBu headroom (1:34) equates to -12 to -9dBFS assuming your interface has a max input level of 12dBu (Scarlett 18i20gen2) and no preamp gain is engaged, correct?
@@ShimiHalperin what dBFS peaks are you referring to? 12dBu would be just below clipping for loud hunbuckers, and a fair bit quieter for single coils. A lot of variables based on the guitar, pickup, player etc so it’s best to take the signal out of the equation and go off headroom of the input (which makes it accurate for ALL signal levels)
When you said in your piece aim for 12-15dBu of headroom (1:34) I needed a way to operationalize that in Logic which only has a dBFS meter. Knowing the max level of the interface (12dBu) and where the preamp gain is set (0dB) makes it easy to bop back and forth between dBFS and dbU. @@eds4754
So if the point is to illustrate that you don’t get a better SNR by increasing gain in the DI, shouldn’t the noise floor rise when you increase the gain? When you increase the gain the max level increases, so wouldn’t this video actually prove that you DO get better SNR when increasing the gain, since it remains at the same level the whole time? Or maybe I’m not quite understanding the context here…. Although I do agree that the guitar signal will have a higher noise floor overall. Definitely won’t argue that.
The level is compensated, so the level (and noise) coming from the guitar is constant. You can see the noise from the converter changing with each different input level, but it’s buried underneath the signal from the guitar. It’s most noticeable in the very top end visually - it’s basically impossible to hear here as the noise from the guitar hides it completely. I’m using an Avalon U5 which has 3dB gain detents, so it’s very easy to compensate for the level.
Finally a DECENT MAN and channel Who will help to put out the final album of the human race. since accurate TECNICIAN KNOWLEDGE IS HIDDEN FROM 99 OF MUSICIAN. YOU CAN BE MOZART BUT YOU CANT PUT OUT THAT ALBUM WHITOUT THIS.
it would appear that the comments are filtered out by YTs spam filter due to them containing links, even obfuscated ones... I've uploaded a quick test with two different interfaces and two different instruments to soundcloud.@@eds4754
Finding your channel has been a game changer for me in many ways but you solved my problem for not only proper DI recording levels but also for re-amping and being able to match the levels in out of the recording desk to what my guitar was sending to the amp in the same chain. Your multimeter method and using the DAW signal generator is so precise and there is no guesswork or having to match sounds by ear at all.
I took it a step further and recorded the DAW signal out of the reamp box and into my loop pedal. I could then set the loop pedal level to output 500mV and then sent that into my DAW and back again through the reamp box and just adjusted my reamp box to get the signal back up to the 500mV. I now have a perfectly level matched direct guitar, DI and Reamp chain.
Interesting when it came to re-amping I had to push my presonus studiolive preamp for the DI to 8db gain so that the signal coming back out of the DAW and through my reamp box could be matched back to the 500mV going into the DI. If I set the preamp to zero db the reamp signal could not get boosted back up to the 500mV level that went into the DI. Probably a quirk with my reamp box.
Anyway your mutlimeter method also helped me to test my signal levels out of my effects switcher and confirmed why I always found my guitar plugged direct into my amp sounded brighter than when I sent my guitar signal via my buffered effects switcher into the same amp. It was doing my head in trying to work out why this was happening. All solved now.
I have quite a complex set up with multiple amp heads being controlled by an amp switcher. My guitar pedals are being routed to my amp switcher via an effects switcher.
Using your multimeter method I found that the signal out of my effects switcher being sent to my amp switcher was lower in mV than the guitar signal going into the effects switcher. The awesome thing was I was able to add a transparent gain boost into the chain to bring the level back up.
And just like that the guitar plugged direct into amp and the guitar into amp via the effects switcher is sounding identical. A huge frustration solved and it was just a slight signal level drop that was causing it. Without the multimeter and using a consistent reference tone signal I could never have solved this mystery.
Anyway thanks for the great suggestions which have helped me immensely.
Love reading this! Exactly the kind of situation where this stuff matters and it makes it very easy to understand which pieces of gear and do what to the signal.
And when it’s set up - you never have to worry about it again, it just WORKS. Well done 👏
@@eds4754 For sure.
It's great not having to 2nd guess anything when you know your signal chain is consistent.
And there is no way your ears can ever guide the required gain adjustments needed compared to the multimeter. Especially with the complex way that tones can change in a guitar rig as signal levels fluctuate.
Excellent!
Theoretically, the signal to error ratio will be higher with higher input levels, but that may be way below the noise floor anyway
yep exactly. The noise from the guitar is what people should really focus on if noise is a concern, that’s where the most gains are
thanks for all ur doing, i love this sort of mythbusting in an industry so rife with misinformation
You’re welcome!
Objectively the best/cleanest way is to optimize SNR of analog domain and ADC, then adjust the level digitally pre-ampsim. Does this matter when talking about extremely noisy guitar pickups? Not really, but this is still an important thing to keep in mind. You are getting worse SNR by doing what you do, just that it doesn't really matter in this particular scenario. I predict so many people getting utterly confused about this. 🤣
Yeah I think the thing is how much of an issue is it going to be and what scenarios? The majority of users are probably already using around 12dBu or less headroom so probably are on the hotter end anyway.
It would take maybe recording guitars 20dB too quiet on noisy old converters and a high gain amp to even notice.
But yeah, stepped gain makes it easy to optimise a good level and easily have something that can be calibrated for various plugins easily. I’m not sure most situations with SNR are worth worrying about, but obviously if it’s presenting an issue there are ways to deal with it.
@@eds4754 Absolutely. I just work as an audio engineer and decided to throw in a comment since these things can cause incredible amount of confusion for those who are not truly familiar with what this all actually means. You know, "some guy said to always record at zero gain because noise doesn't matter". Then this morphs into a some sort of universal mystical truth, and it ultimately leads to me having some noisy drum tracks to mix because "we were clever and did the right thing while recording!". 🤣
That being said, one thing I do hope for is that plugin manufacturers would start to offer better information about these kind of things. I mean the "best practice" of recording at healthy levels to maximize SNR isn't that great in this context if this means you feed your ampsim ~10dB too hot. Manufacturers should offer some kind of tools for a user to correctly a) identify that this can be an issue (i.e. level matters), and b) how to set their input gain correctly within a plugin (at least roughly). I mean I don't expect a regular Joe to understand how their interface's preamp actually works, or how their AD/DA translates voltage values between analog and digital dBFS, or that any of this has anything to do with their guitar sound. No, a plugin should inform user clearly about levels in one form or another (i.e. what is the reference level for a "correct" amp behavior).
@@knzznk3507 I totally agree! The main issues are people doing things without really understanding why they’re doing it, and also, the lack of information from plugin manufacturers, which there really is no excuse for - their assumption is everyone is too dumb to understand and that just achieves nothing.
the main reason I made this video is because of the amount of replies to my other videos about “what about SNR?!” and it’s really to show that there is often other stuff that may be more of a concern.
Makes perfect sense.
Didn't think about that, but it does make sense that the noise floor of the pickups is much higher than the interface. And I guess at least in 24 bit quantization is also a non issue. That leaves the smaller wave forms (depending on the DAW) as the only real annoyance when recording guitar at minimum gain I guess. Thanks for sharing. :)
Ha yep. But all DAW's have the ability to zoom in on the waveform, so just use that if you need to see things more clearly. There are often other waveform views that can show different kinds of information about your signal. Its actually quite hard to record a DI signal that is too quiet, most gear at their lowest levels will produce a healthy signal.
Good job!
Thank you!
Surely the solution is to track the Dis hot, with the most efficient signal to noise ratio, and then turn down the input gain on the plug in, as to feed it the ideal signal. That way having a dynamic and clean signal with a low noise floor but still feeding into the amp at an ideal level, that reflects the amps sound accurately.
Of course. I’m just demonstrating what the actual real world benefits are.
What conclusion can you draw from the video? Does a higher input level produce less noise? What is the highest source of noise in the recording chain?
@@eds4754 I'd guess that due to the nature of analog to digital conversion, that higher input gain is the way to go, as to have a cleaner signal. I'd think that it would then be ideal to turn down the input in the plug in or DAW. Which unfortunately is a massive hassle. I just want to plug my guitar into a plug in and get great tones without having to worry
How best to shield or ground my guitars? I get terrible noise from mercuriall 6160 stealth into my 7 string Ibanez.
conductive paint or copper inside the cavities and around the body of the guitar behind the pickups, make sure the wiring is done well with good components etc. Make sure that you connect the shielding to ground otherwise it won’t work. Always touching the strings or somewhere metal on the guitar while you play also helps.
You can also check for things in the room that may cause noise and find areas (and even angles to point the guitar) where noise is quietest.
A good guitar tech should be able to ground your guitar properly if you need help.
also make sure you are using the correct cables, and hi z input (or di box) with a suitable impedance. and also things like laptop charges can add noise so try to find the cause of any problems be removing them one by one and seeing what effect they have
I was trying to match noise level of Golde Age preamp and noise level of pickups on my guitar to find perfect recording level,becouse noise flor of preamp stays the same if you turn it down,so i had to find optimal level for recording,and ofcourse to find the perfect position where noise is lowest.
This is why when recording, I never use a noise gate. I always want to hear how much noise is happening so I can get the best angle
Same here. Also, check out the free Bertom Denoiser plugin, it’s amazing for transparently removing noise
@@eds4754 thanks for the recommendation!!! It seems as good or better than Ozone
thats true thanks for doing this, it seems that all of us are having that RF shit over the tracks, but its true moving or keep you far from your pc or monitors helps, signal to noise ratio doesnt affect the noise level as you show here, but maybe using a real mic could be different?
It’s all about minimising what gets into the pickups really, there’s usually a spot in the room where you can angle the pickups and the noise will be quieter. Also touching a metal part of the guitar and making sure the shielding is grounding gets it down.
The noise going into the amp would be no different, but amps are much noisier than recording DI’s because valves and analog gear has a much higher noisefloor
I am keen to know how you would approach getting input levels for tonex calibrated?
It seems due to IKs less than stellar software I basically have to tweak my presets in their plug in or standalone app and then transfer the preset to the pedal.
Regarding the app I haven't seen Tonex mentioned in your reference level specs like you do with other amp sims.
What reference level would you say is the most appropriate for the tonex factory presets to sound accurate?
Do you also use the Tonex pedal? If so how do you approach calibrating the input level into the pedal so that the app and the pedal are aligned in terms of preset sounds?
I assume it is not the same as calibrating a guitar reamp chain and the tonex pedal probably wants a higher input level to what the guitar is putting out and a level that is different to what I am sending into the app via my DI.
I guess I could do it by ear but it would be great if there was a way to measure the signal chain and get it all more accurate like you do with your multimeter for your DI and reamp levels.
The IK stuff sounds great but the implementation of their pedals and software could be done so much better.
For tonex, the input level depends on the reamp level used to create each model. So each “creator” is essentially like their own plugin developer with their own dBu specs, rather than there being one consistent level.
Furthermore, IK don’t provide any guidance or recommendations for levels for their own or anyone else’s models and even their own interfaces and reamp boxes have totally different specs and would yield different results. I have no idea what level they use for their models, I genuinely can’t seem to make them sound good no matter what. I don’t have the pedal but I think when it’s set to 0 on the input gain it’s about 8dBu IIRC.
You can measure it by using the device as an interface and recording a 0.775V sine wave through it and seeing what dBFS level you get.
Had IK implemented this properly, each users input level could be embedded into each capture and the software could automatically adjust so it’s correct for every user for every guitar. It’s a mess of IK’s making and unfortunately asking them for any more information or help just leads to silence. I agree they make some cool tech, but other aspects of the company let them down completely. Tonocracy tried to remedy these input level issues in their software which imo is a little more accurate than tonex too (but not quite as accurate as NAM).
Thanks for the quick reply. Appreciate it.
I think IK are happy for the general users business who don't understand or don't care about this stuff but eventually people will grow to hate their tones and the number of negative posts will start to grow.
I guess the smart people selling their own tonex captures should at least provide some guidance to their customers on their captures if they want good reviews and more sales.
@@TheBukmanYeah I agree. IMO if someone is selling captures they should provide this information so users have the means to achieving the most accurate tone if they desire.
If this value isn’t known then it really doesn’t give customers the chance to hear the amp in its original form, as it was dialled in prior to capturing.
Generally it leads to a lot of redundant models and processing, and just clutter because so many models end up sounding similar EXCEPT for the input levels.
Ah well.
Does this essentially mean it's pointless to use a DI with an amp sim? What about the conversion of an unbalanced to balanced signal?
Highly appreciate you work, by the way!
No, you need a DI box (or instrument input) to handle the impedance mismatch between a guitar and line input. You can use an instrument input on an interface or an external DI box, just aim for one with a minimum of 1M Ω impedance so it presents a high enough load to the pickups
12-15dBu headroom (1:34) equates to -12 to -9dBFS assuming your interface has a max input level of 12dBu (Scarlett 18i20gen2) and no preamp gain is engaged, correct?
Sorry, I meant -12 to -15dbFS. Went the wrong direction.
@@ShimiHalperin what dBFS peaks are you referring to? 12dBu would be just below clipping for loud hunbuckers, and a fair bit quieter for single coils. A lot of variables based on the guitar, pickup, player etc so it’s best to take the signal out of the equation and go off headroom of the input (which makes it accurate for ALL signal levels)
When you said in your piece aim for 12-15dBu of headroom (1:34) I needed a way to operationalize that in Logic which only has a dBFS meter.
Knowing the max level of the interface (12dBu) and where the preamp gain is set (0dB) makes it easy to bop back and forth between dBFS and dbU. @@eds4754
So if the point is to illustrate that you don’t get a better SNR by increasing gain in the DI, shouldn’t the noise floor rise when you increase the gain? When you increase the gain the max level increases, so wouldn’t this video actually prove that you DO get better SNR when increasing the gain, since it remains at the same level the whole time?
Or maybe I’m not quite understanding the context here…. Although I do agree that the guitar signal will have a higher noise floor overall. Definitely won’t argue that.
The level is compensated, so the level (and noise) coming from the guitar is constant. You can see the noise from the converter changing with each different input level, but it’s buried underneath the signal from the guitar. It’s most noticeable in the very top end visually - it’s basically impossible to hear here as the noise from the guitar hides it completely.
I’m using an Avalon U5 which has 3dB gain detents, so it’s very easy to compensate for the level.
Finally a DECENT MAN
and channel
Who will help to put out the final album of the human race. since accurate TECNICIAN KNOWLEDGE IS HIDDEN FROM 99 OF MUSICIAN. YOU CAN BE MOZART BUT YOU CANT PUT OUT THAT ALBUM WHITOUT THIS.
is everything OK pal?
Guitar tinfoil incoming
Are you deleting my comments?
No? this is the first one that has shown up
@@eds4754oh that’s weird. I’ve tried twice to post a comment. Sorry! I’ll try again lol
@@anonymus8760Ha all good!
it would appear that the comments are filtered out by YTs spam filter due to them containing links, even obfuscated ones... I've uploaded a quick test with two different interfaces and two different instruments to soundcloud.@@eds4754
Most likely UA-cam shadow banning you. Terrible anti speech algorithms