Measuring the pickup output (not resistance)

    Hi folks,


    There is a theory that I would like to test. The output of a pickup will increase ifit is closer to the string. My theory is that at some point, raising the pickup does not increase the output anymore. Raising it beyond this point may have the effect that if you play 'half loud', the output is maxed already. If that is the case there is less dynamic range. I am referring to the output signal on the guitar cable where it enters the amp. To test this theory, I wanted to lower my pickup, play 'loud' then measure the max output. Then increase the height a bit and repeat until the max output doesn't increase anymore. Then in theory it should have the maximum dynamic range. Of course it doesn't mean it will also sound good but that is not the point here.

    I have a Kemper Stage connected through S/PDIF to an audio interface. If choose a rig and turn the amp, cab and all effects off, I think I have a clean signal.

    The question is now, does anyone have an idea on how to record the signal on Windows in a meaningful way? The signal has a very low output. I have a DAW Performer Lite which I can maybe use to record the signal and review it. As said though, the output signal is very low and not sure if it will work correctly if I try to boost it.

    I hope I can get some tips and then I will report my findings here :)

    Thanks in advance.

    Quote from Pier75

    My theory is that at some point, raising the pickup does not increase the output anymore. Raising it beyond this point may have the effect that if you play 'half loud', the output is maxed already.

    That does imply that there is some sort of clipping happening somewhere in the signal chain and I honestly don't know what could be the 'literally' limiting factor in this scenario.

    Quote from DonPetersen

    That does imply that there is some sort of clipping happening somewhere in the signal chain and I honestly don't know what could be the 'literally' limiting factor in this scenario.

    If I am not mistaken, it has something to do with the magnetic field, where at a certain distance the generated signal will not increase when the string vibrates. It is called magnetic saturation according to jefrs in this post: https://www.tdpri.com/threads/…reble.220602/post-2612876

    My goal is just to find the pickup height just to the point where max output is only reached when attacking the string very hard. When this is found, the next step will be to determine if I personally like the sound or not. Hope it makes sense...

    If you plug your guitar straight into your audio interface and record, that should show you the pickup output.


    The problem will be picking the string/strings the same for each test. And if you start strumming loud chords you may get frequency adding / subtracting that may cloud what you are trying to see?


    But in theory your guitar pickups put out a voltage. And recording your guitar straight is measuring that voltage.


    It may help if you could measure the RMS value of the recording. If you were getting some compression it may show a higher RMS value if the signal was normalized (maxed out).


    Normalizing is the standard term. It could be called maximized. It means add gain to the signal so that its loudest sample is full blast. Most audio is changed from its normal value to a value between -1.0 and 1.0. So normalizing a reading of .6 max would change everything so your max reading is 1.0.


    I AM NOT AFFILIATED

    I always use Goldwave for my audio work. I think it is PC only (no mac) but the author will let you run it free for a while. In GW you can record, normalize, and then zoom in to the sample level, etc. It used to show an RMS value in the maximize (normalize) section but it was removed sadly. It is one app I run every day if I am playing guitar or not.


    1) So I would get GW.

    2) Set pickup low and record myself playing very loud.

    3) Selecting the MAXIMIZE (speaker with ! next to it) button will show you your loudest reading.

    4) Repeat steps 2+3 with new pickup heights.


    Like I said you will see a lot of weird peaks and transients when picking and strumming hard. So it may be tough to get a grasp on how much the pickup height is working. Or it may be crystal clear, who knows :)

    Quote from Pier75

    It is called magnetic saturation

    This is why I was saying you may need to measure the RMS value of your waveforms. The peaks may not get louder but the softer parts of the sound will get louder (more compressed). This may show up as an increase in the RMS value of the waveform.


    But in this case to just get started, reading the waveform peaks may tell a story.

    in the end, it's all about how it sounds.

    (good) ears will beat measurements at any time.
    even if the measurements taken are accurate, it is quite hard to determine what that actually means, due to the way our hearing and the interpretation of what we are hearing works.

    I've been posting for years, that adjusting the pickup height and angle is one of the most powerful things you can do to fine-tune your sound.
    It only takes a screw driver, ears and a bit of time.

    Thanks for the info. I think I would test it on 1 string only to avoid adding or substracting output signals from the other strings. If the theory is correct, then the peak volume (not RMS) will hit a ceiling when this magnetic saturation is reached. I found that you can get a dry signal as output on the Kemper so I will use that. Since the pickups and some part of what you are plugging into form a single circuit that influence each other, that would probably be safest. I will report my findings here :)

    Very true! We'll see what my ears make of this little experiment. Maybe it will sound awful, who knows... :)

    For my two cents:


    Wouldn't the diameter of the string alter the location of this saturation? Assuming so, then one string will be 'right' and the others not. Angling the pickup is a simple solution. Except the effect is likely not linear. There's a reason some pickups have staggered pole pieces.


    I mean...by all means have fun, whatever that looks like to you.....but rather than chasing a theoretical point and *then* deciding if it sounds good, why not just get on with it and adjust the pickup heights until you find what actually sounds best to you?


    Use your ears (which is what you've said you're going to do, anyway). Then take the extra time to play more.

    “Without music, life would be a mistake.” - Friedrich Nietzsche

    Like 1
    Quote from Ruefus

    I mean...by all means have fun, whatever that looks like to you.....but rather than chasing a theoretical point and *then* deciding if it sounds good, why not just get on with it and adjust the pickup heights until you find what actually sounds best to you?

    Some of us do not have great ears. Playing a sound then tweaking pickups and playing again later would not be clear. At a minimum we need to record it so we can compare side by side. And since you are going to record it anyway, you may as well check the data visually.


    And the tone changes may be very small and will react differently with different profiles. So doing it visually may get you closer over a broad range of profiles.


    Your logic is correct, tuning by ear is fine for most people. But not for everyone.

    Quote from RosboneMako

    Some of us do not have great ears. Playing a sound then tweaking pickups and playing again later would not be clear. At a minimum we need to record it so we can compare side by side. And since you are going to record it anyway, you may as well check the data visually.


    And the tone changes may be very small and will react differently with different profiles. So doing it visually may get you closer over a broad range of profiles.


    Your logic is correct, tuning by ear is fine for most people. But not for everyone.

    That's fine, but OP has already said he's going to use his ears in the end.


    I've never known any player to use diagnostic tools to determine good tone before. As an engineering/knowledge exercise, OK. I get totally get that.

    But you can't fire up a frequency analyzer or whatever else and generate a good sound staring at a screen. At some point your ears have the final say. My point is why go through all that when your ears are going to decide regardless.

    “Without music, life would be a mistake.” - Friedrich Nietzsche

    Like 1
    Quote from DonPetersen

    ?

    I think you are asking me to clarify:


    Some people will have a hard time noticing small changes in pickup height. This is made harder because there is time between the changes.


    It is easier to hear the difference when you have two sound clips you can instantly bounce between.


    Since these people will need sound clips, they may as well look at the waveforms and learn what is making their ears happy. Then you could tune it by eye to get close. Or at a minimum reinforce what your ears are saying.


    Basically the whole concept is flawed for some people.

    - Play some notes.

    - Grab a screwdriver.

    - Tweak screws.

    - Put down screwdriver.

    - Play some notes.


    Did you pick it exactly the same way both times??? Same chords? Notes? etc. Do you remember the finest details of the sound between plays???


    Just saying looking at waveforms will make you understand why it sounds better, so why not do it?


    But there is no right or wrong way. Its music. :thumbup:

    Quote from RosboneMako

    Some people will have a hard time noticing small changes in pickup height. This is made harder because there is time between the changes.


    It is easier to hear the difference when you have two sound clips you can instantly bounce between.

    making recordings and switching between them is something else entirely. It is still tuning by ear. You implied that some people need to tune by eye "tuning by ear is fine for most people. But not for everyone."

    Quote from RosboneMako

    Just saying looking at waveforms will make you understand why it sounds better, so why not do it?

    IME:

    If it would work, yes it could be a viable way to get another perspective at things.
    As someone who has spend more time than I care to admit over audio analysers of all sort to measure fuzzes, ODs, their tone controls - tried to figure out a setup to reliably measure the tonal effect pickups have etc... (this was all pre-Kemper btw. and I had nothing to do with the STOMPS etc. in the PROFILER, except making a few presets for them)


    It doesn't work.
    And if it does, you could have come to the same or better results much quicker by using (and thereby further training) your ears.
    As highly visual creatures this is a hard lesson.

    The only time I do use frequency analysers is to check the amount of highpass I put on guitars especially, since my monitoring situation - while quite good - is of course not perfect and the low end (and low mids) are always the areas where the mix issues lurk.

    I'm a bit confused here.....


    There is a massive industry that makes pickups - they understand the physics at work and there are suggested pickup heights and I'm sure they recommend optimum heights. These vary as its impacted by string gauge, how hard you hit the strings etc.


    Seymour Duncan Pickup Height | Seymour Duncan


    Hand Wound Guitar and Bass Pickups | Bare Knuckle Pickups


    So an element here is personal taste so not sure you can analyze this effectively.


    Also another factor that affects max pickup height - too close to the string starts to create string pull which is a very negative effect on the strings ability to vibrate.


    I had a new pickup fitted as part of the retro fitted trem. I got it home and the pickups looked a little low, so I raised them to a height that looked about right. I played live a few hours later (with screwdriver ready just in case) and all was fine.


    That was good enough for me..ultimately it has to be your ears that decide.

    Quote from RosboneMako

    Some of us do not have great ears. Playing a sound then tweaking pickups and playing again later would not be clear. At a minimum we need to record it so we can compare side by side. And since you are going to record it anyway, you may as well check the data visually.


    And the tone changes may be very small and will react differently with different profiles. So doing it visually may get you closer over a broad range of profiles.


    Your logic is correct, tuning by ear is fine for most people. But not for everyone.

    Hear hear! Also I believe your ear 'memory' is in a range of seconds so that can make it difficult to compare sounds if the time between the sounds is too long...

    Ok I executed the experiment:

    Set the S/PDIF output on the Kemper Stage to 'Git / Stack' so the left channel has the unprocessed guitar signal.

    Using Performer Lite, setup a mono audio track to record the left channel.

    The neck pickup height was about 2.4mm for the low e and 2.0 for the high e. I used 6 full turns on each side to lower it.

    Record the signal while playing soft to hard on the open low e string, then soft to hard on the 5th fret, then 12th fret, then 19th fret.

    Raise the pickup adjusting the screw 1 full turn, record again.

    Repeat.

    As the amplitude of the signal was getting louder as the pickup was raised, there didn't seem to be a spot where raising it didn't increase the amplitude of the signal. So I did not find a spot where this 'magnetic saturation' occurred. I raised it until the pickup hit the string when fretted on the 19th fret.

    Same result for the high e string and same experiment on the bridge pickup.

    It seems that it is non-scientifically proven that on my Gibson Les Paul 50's, which has a Burstbucker 1 and Burstbucker 2 pickup, a sweet spot does not exist for the pickup height where you get a maximum dynamic range, due to this 'magnetic saturation'. My hope was this spot existed and would make it the best spot for the pickups to be in and it would be the 'best spot' for them to be in. Also, from judging the waveform of the signal, there is no clipping of the amplitude. So I guess the height only changes the amplitude of the signal, and maybe the (diustribution of) harmonics.

    I also noticed that the difference in amplitude is pretty big. So higher or lower pickups using the exact same amp may have drastic effects on the tone, one might not get the amp to distort and the other might distort it too much. Is there a gain setting for the input signal?

    I think you've proven what I suspected.... the pickup will interfere with the strings before reaching the saturation point.


    As a result I try to set my pickups as high as possible to get maximum gain from them but without getting string pull.


    Nice one dude!