12v power fastest transient response solution

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falken1208

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I noticed when I recording electric guitar through audio interface. the result is heavily affected by power transient response. dont know why my ac mains are very slow and my waveform is not sharp. im now looking for offline fast transient response 12v power solution? do you have any idea?
 

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I did not mean wireless signals are the problem but rather any cable acts as an antenna to any E-field like from the grid which can cause saturation or clipping distortion on the preamp at the cable end. This is where a good ground and an RF snubber cap shunt may be necessary.

I guess we need an audio recording to analyze your noise on quiet and a single string note to see the SNR and spectral noise and distortion.
 

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If there’s no noise when you’re not playing, and there is when you are, that’s distortion. it’s not noise pickup. BTW, do you have any compression in the signal path?
 

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Look at plain reply window which shows icons so you can include images or video. Can your phone shoot video w/sound? Then upload video via movie camera icon whose caption says 'Insert video'. Or put your video on Youtube and post/share weblink.
 

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if I do not touch the strings, guitar is floating. there is a lot of noise. Can I say that the noise is
barry said:
If there’s no noise when you’re not playing, and there is when you are, that’s distortion. it’s not noise pickup. BTW, do you have any compression in the signal path?
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I dont have compression. active pickup cliping is internal, so the wave form looks hard cliping.
 

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betwixt said:
Tony's idea is a good one, can you post a recording here, only a minute or so long but demonstrating the effect so we can hear it for ourselves.

Brian.
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betwixt said:
Tony's idea is a good one, can you post a recording here, only a minute or so long but demonstrating the effect so we can hear it for ourselves.

Brian.
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here attached 2 mp3 files you could listen to. me fisrt and then american producer's.
let me explain. because the difference is not as big as you wish especially if you are not familiar with guitar recording. but please trust me my recording is lacking of that polishing brightness，the steel string sound. my guitar setup is as the same as the american producer and everything else close as well. mine is distorted with less dynamic, it is lifeless. I dont think its a guitar problem. or gear problem.
it is really caused by dirty signal for some reason, tiny current power error.
I already used a 3F 12v supercapacitor to absorb voltage noise， so my waveform looks much cleaner.
the headroom ,spatial , brightness is the key for good guiar. if Im not with signal error. mine would be as good as him.
 

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Your mp3's playback with no problem. They sound very different. The 'gain' file sounds like it has a fuzz effect. Is this intentional? If not it sounds like a super-sensitive amp (meant for microphones) being 'overloaded' by a signal such as delivered to a speaker. I believe an attenuating patch cord would help here.

The 'di' file is guitar with no fuzz, no clipping.
 

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DI file sounds different, first one is mine, it is slightly off. a correct one should not be that dull, mid ranged , less topend brightness and close to ears. I would call it totally wrong, it is because of some distortion go along with my clean signal. most probablly that high impedance interference as D.A.(Tony)Stewart said.
the second one is from pro american producer with average american clean power. It has everything to my ears.
I lived in US during 2013-2016, I do not have any problem at that time. life changed when I relocated to China.
and im pretty sure for digital transform and transition there should not have any problem. the problem is happening at the analog part ahead of ADC chips
 
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I’ll confused. You “don’t think it’s a guitar problem”. You are comparing DIFFERENT GUITARS? One from an American producer and one from you? Are you saying you’re comparing two totally different setups?

The two tracks are totally different. It doesn’t sound like distortion differences to me; one track is MUCH brighter than the other. The EQ is totally different.
————-
After another listen, it definitely sounds like one recording also has more overdrive.

It’s impossible to believe this has anything to do with line voltage.
 

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please trust me. I have been recording for 8 years. pro gears, no noob setting mistake. Im very clear what Im hearing is all based on power. there is not so many people recording guitar to the best. after 5years study. I promise the secret is all in power quality. i could sit here in my house using battery and ac mains to get totally different recording results. but I dont know how analog signal has been influenced by power.
me and that american producer are using exactly the same guitar setup. and I tested with different guitars. all my recordings are dull, its not possible that all my guitars are dull. I know how different guitar can shape the tone. but now I finally focus on power difference after so many a/b tests. if it is a gear problem. 10 guitars 5 audio interface 5 computers would have made at least a litter progress. but no, only different power source sounds different
--- Updated ---

If I have time in weekend, I could take my gear to different place around my city to show you how same gears could sound so so differnet with power source
 
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I am not clear on how each recording was produced. (guitar, settings, power source) I don't even know what is the "American Standard".

It is possible that if your DC voltages are different between battery and ACDC converter that your clipping levels will change and that means it will sound different. A poor unregulated ACDC converter will have a DC voltage that is proportional to the AC voltage going in using a transformer for the ratio. If that is truly what is happening to you then all you need to do is measure the voltage where it sounds best and use a DC voltage regulator for that voltage in both AC and battery mode of operation. Clipping or boost thresholds that are DC voltage sensitive or limited will affect the harmonic content and thus the spectral shape.

You can measure the AC voltage and DC voltage with a cheap $10 DMM if you want to analyze this problem properly. Then we can help you fix it.


The "american std." has a boost above 100 Hz (or 4th order cut below) and then a 5th order cut (lowpass)

Your SNR is excellent (with fingers on) and that means your hum pickup is suppressed by your body's capacitance effect to the air and earth ground. (PE) Where all it takes is a fingertip to get 1 nanofarad(nF) or so of capacitance to PE ground. Your whole hand on the strings might be around 50 nF. This hum suppression effect could be replaced with a fixed capacitor inside your amplifier to the PE gnd anywhere. But this is a different issue that affects your sound due to clipping and filtering. So let's mind that hum pickup and guitar sound effects like attack/decay, fuzz, harmonic shaping, compression and spectral shaping are two different issues.


FWIW
The break between your two repeated riffs has a spectrum is "white noise" i.e. flat 0 dB between takes. so you are recording flat and clean (with fingers on).
"Pink noise" is flat to our ears but is -3dB /octave, (aka half-order, -1/2)
"Brown noise" is -6 dB /octave (aka -1st order is called that because the filter only uses one reactance. e.g. one RC filter with one capacitor)
" real dirty" I suppose is low pass filtered higher than 2nd order (-12dB/octave= -40dB/decade) in the mid range.
Your original clip is filtered to -12 dB/octave (aka -2nd order) above ~ 1kHz. low pass filter.

Let's examine the "american standard"


I would think this is dirty with no bright spots and muted above 5kHz to make it sound less tinny and more dare I say, "heavy metallic" as weight of damping can frequency response.


Now you say your cut is "dirty" because it lacks the high end. You have a 2nd order low pass at 300 Hz and the negative down slope after 300 Hz drops 40 dB per decade or 12 dB/octave to 3kHz or same from 1k to 10k although it still has harmonics to 20 Khz which is the recording bandwidth. (BW)

.


To make the 2nd one sound like the 1st needs the correct boost filter, clipping level and then cut filter after or the difference in slopes between the two.
But we need to know your AC or DC voltage changes with your desired effect (good or bad) for the sound effect to work properly.

There are other ways to regulate this with compressors that use precision references.

There are also smart guitar effects amps. This one caught my eye.


 
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a lot of useful information, thank you.

1. Let me explain more about guitar DI. DI which means direct input, is to use only guitar itself without any effects . there is no overdrive, no gain, no boost and no EQ. the purpose is to keep the guitar signal as original as it could be at pre-production stage. and to get more flexibility in later adjustment.

2. I checked that spectrum analysis. I think it contains both acoustical and electric character. Acoustically these frequency response diagram defined that it sounds like a guitar. not vocal or piano. I tested early ago with different guitars. it has slightly different specturm. but not as that much as China power vs american. so except for some acoustical difference. I do think my guitar spectrum should at least look close to the american one to sound correct. it should have those meat above 300hz. but I dont think a post EQ effect could do that. I did Spectrum match to reshape it. but no it dont sounds like it.
I have a question, did you mean that every AC or DC power has its own unique frequency response and it will overlay with the acoustical character？


3.as for the voltage. at the rear of audio interface, it shows 9-15v . I suppose it has secondary rectification inside no matter to use DC directly or use 220v to 12v PSU.
And for different voltage level. I think they sound the same. the audio interface is a very sophisticated electronic device and there will be no problems with the integrated digital circuit part. its as the same as a small computer. no matter how bad the power is, it can hardly make data error.


let me expalin how I tested everyting for 5 years.
1. guitar and cable are easy to test. I own a lot of them custom made strandard build. and some of them are as the same as the american producers used in almum after I emailed them to confirm their setup. guitar‘s tone difference is obvious. It could be fuller thinner brighter darker in a range. but my Di quality is not in the range. my distortion is not caused by guitar acoustically. 10 of 10 my guitars dont sound at least a little closer to their recording quality.
2. gears： I used to have some expensive mic pre , di box and audio interface, which pro producer may use. But the can shape the tone so silghtly. after a lot tests they cannot fix any of my problem.

these two can make tone difference happen, but what Im suffering is more like signal error. So lets do not talk about acoustical difference and focus on electric power.
if american producer recording is 100 score. my apartment recording is 50%. one time I bring all my gears to a Chess and Card Room in a new constructed commercial area，I know its power line is new, and I got 80%. Thats how I know good power is the key.
but except for voltage noise. I still dont know what spec in electric power can make my signal perfect.

 

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What you fail to note is that the equipment doesn't work directly from the AC power line, it gets converted to DC first and in almost all circumstances is regulated to a fixed voltage. That makes it impervious to all but the most extreme AC fluctuations. I can listen to music through my amplifier here when the AC is so low the house lights only flicker dimly and it is exactly the same sound as when full voltage is restored. I can play music perfectly when running on an old Diesel generator which varies not only voltage but frequency as other loads on it are switched on and off. As it passes through the power supply exactly the same DC comes out regardless of what goes in.
I'm speaking from experience having just had power restored after 4 days on batteries and generator due to a storm taking down the overhead power cables!

Brian.
 

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This seems to be the FACT that the OP refuses to accept. How many people have to tell them: “The AC power is not your problem”, yet they still seem to believe it is.

I’m done.
 

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barry said:
This seems to be the FACT that the OP refuses to accept. How many people have to tell them: “The AC power is not your problem”, yet they still seem to believe it is.

I’m done.
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In my a\b test, power is the only variable factor. everything else is the same. I put a 12v battery side by side with ac power. I can switch between them in a minute. And I recorded get 2 files. checked agian and agian side by side. it is so different. and I repeat this test over the past 5 years.
If AC power not a problem, why power source makes so huge difference even much more than my guitar setup and all gears?
I recorded and have all the files to double check. Im not under delusion or psychological problem.
I do believe for any digital device, a computer, a led screen, a TV ,power quality hardly make any difference. but guitar is made of magnet and wires. they are not advanced. and we dont know how audio interface read analog signal，it transforms a high impedance analog signal to digital data. everything could happen there.
 

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falken1208 said:
but guitar is made of magnet and wires. they are not advanced. and we dont know how audio interface read analog signal，it transforms a high impedance analog signal to digital data. everything could happen there.
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We know how electronics works. I design electronics prefessionally for decades. Including analog and digital audio.
It´s not a woodoo magic. It´s all physics, math.

Klaus
 

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KlausST said:
We know how electronics works. I design electronics prefessionally for decades. Including analog and digital audio.
It´s not a woodoo magic. It´s all physics, math.

Klaus
Click to expand...
KlausST said:
We know how electronics works. I design electronics prefessionally for decades. Including analog and digital audio.
It´s not a woodoo magic. It´s all physics, math.

Klaus
Click to expand...
if you want to look at a footage showing the different power makes the difference in one minute I can upload. Its not difficult to shoot a phone video.
 

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Like Klaus, I've worked in electronics, particularly in electro acoustics for now 54 years (ouch!) and assuming you are using isolated (=safe) power for your equipment whatever is creating the difference is not the power source. Please do show us video, we might be able to spot what really is causing the difference. We are not doubting your ears but experience makes us think your diagnosis of the problem is wrong.

Brian.
 

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When a unit specifies 9 to 15Vdc input, that means internally the voltage is DC regulated and won't be affected by any voltage in this range regardless if it comes from a battery or ACDC converter. There should be no difference in the amplifier performance.

The room acoustics and acoustic feedback will affect the guitar response.


>I have a question, did you mean that every AC or DC power has its own unique frequency response and it will overlay with the acoustical character？
No I was imagining a different DC voltage would cause a different clipped level, but you indicated you are not operating clipped or distorted into the Di amplifier. Then nonlinear signal conditioners (e.g. fuzs, compression etc ) will react differently in spectrum to input levels, was what I meant.

We need more examples of good and bad for the same input to understand your situation, to achieve what you want, as the descriptive 'american std" names don't seem to help although the initial recording was helpful.

I too have had similar experience in acoustic engineering since the 70's.

It is important to play the same notes for comparing results. In electronics, we use a step waveform because this includes all the spectrum equally, so there is no confusion. That is just an abrupt DC change on voltage or step and inverse step which is a pulse like a drum stick on the rim.
 
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falken1208 said:
if you want to look at a footage showing the different power makes the difference in one minute I can upload. Its not difficult to shoot a phone video.
Click to expand...
You blame it on AC .. .but I´m rather sure AC is no the problem.
You call it transient reponse ... but I´m rather sure that this is not the problem.

When discussing problems with people .. I´ve learned to describe a symptom ... but not biasing "my idea" what maybe causes this symptom.
And I´ve learned to use "objecitve" sources and measurement equippment.

And I´ve learned to find a root cause .. one should use the most minimal setup that is able to reproduce the symptom.
It´s like blind studies to avoid any subjective influence (wanted or not wanted) --> the scientific approach.

***
We are at post#60 and still turing in circles. Thus I don´t like to spend more time, so I just try to make it short.

Playing a guitar is very subjective. And if you (personally) try to elaborate on a sound problem ... I recommend to let someone else play the guitar (no need for a real guitar player) and you do your measurements and chage in setup without any visual connection to the guitar player.
The guitar player is told to simple repeat the same movement. The guitar player should not know what you changed in the setup, not she hould he see your face gestures.
(There are quite a few historic examples where the expectation influences the result. Like the "Clever Hans")
Even better if you can produce a guitar sound (as test signal) without any human influence at all. Maybe a metal ball on a string ... left from an fixed point ... so that the ball always hits the guitar string at the same position and with the same force.
You then make some "reference" measurements (without any change in setup) just to see the "variation" in output without any variation in input and setup.
Then "measure" your results to get numbers. Numbers are comparable.
You can measure (example)
* rise rate in V/100us
* clip level in volts
* overtones in amplitude
* signal to noise in dB

****
My idea .. what´s behind the whole problem .. may be (as others already wrote)
* One supply may generate a higher DC voltage than the other ... making the sound clip less
* one supply may generate a voltage with a higher source impedance (less stability) .. this may cause the sound signal to clip differently .. or even add some DC offset (for a short time) that makes it sound differently.
* one supply may be uncritical for high jumps in current .. whil the other may tend to oscillate .. and thus add some ringing.
* One supply may add some voltage with respect to earth ground. .. and this may make the sound to change
* one supply (wiring) may cause a ground loop to send out and pick some extra noise.

The soud pick up problem and ground loop problem is well known, that´s why professional audio equippment uses differential signaling and maybe even audio transformers.


Klaus
 

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