MC208
New member
What do you mean still no guitar? The recording has the guitar in it. I made the recording via the USB from the mixer to the computer. Yes, my mixer is from 2012, it's been a great mixer though!
TalismanRich
Well-known member
Dave apparently didn't play the clip far enough.
Comparing the first section to your clip with the guitar, the hiss was at about -47dB. The hum part was about -40dB, so 7dB of additional noise. The guitar section peaks at about -4. But, the hiss is clearly audible. I'm not sure where that is coming from, the ZED, your guitar, your volume settings (improper gain staging), pedals (do I hear a bit of a compressor? The hiss seemed to pump a bit).
The hum you are getting when you don't touch the guitar shouldn't ever be an issue, as you HAVE to touch the strings to play the guitar. The hiss, on the other hand, is a bit of a problem, although with a full band playing, most people wouldn't notice it. But people who listen for that stuff definitely would hear it. ~43dB S/N isn't a very good level.
Comparing the first section to your clip with the guitar, the hiss was at about -47dB. The hum part was about -40dB, so 7dB of additional noise. The guitar section peaks at about -4. But, the hiss is clearly audible. I'm not sure where that is coming from, the ZED, your guitar, your volume settings (improper gain staging), pedals (do I hear a bit of a compressor? The hiss seemed to pump a bit).
The hum you are getting when you don't touch the guitar shouldn't ever be an issue, as you HAVE to touch the strings to play the guitar. The hiss, on the other hand, is a bit of a problem, although with a full band playing, most people wouldn't notice it. But people who listen for that stuff definitely would hear it. ~43dB S/N isn't a very good level.
TalismanRich
Well-known member
Here are the noise profiles for the 4 sections (ignoring the first couple of seconds were you got some hum.
The main hiss is primarily around -90, but there is still some hum that pops up to about -65dB. The hum section is more like -52dB for the highest peak. The highest peaks for the music parts are around -20dB.
The hum is classic... .60 cycle and multiple harmonics which you hear more than the 60 cycle unless you have a subwoofer.
The main hiss is primarily around -90, but there is still some hum that pops up to about -65dB. The hum section is more like -52dB for the highest peak. The highest peaks for the music parts are around -20dB.
The hum is classic... .60 cycle and multiple harmonics which you hear more than the 60 cycle unless you have a subwoofer.
MC208
New member
No compressor, just a reverb pedal. I'm not certain about the hiss either, but the hum is definitely less using the MDA1. I'm thinking about buying a better one, at least to try it and see if it remedies the problem.
AI seems to agree the hiss is coming from the MDA1:
It seems like the MDA1, although it lowered the volume of the hum, it seemed to introduce a lot of hiss. Is that normal?
That's a very sharp observation, and you're not imagining things. It is a common and understandable trade-off, especially with entry-level gear. The hiss you're describing is likely circuit noise from the MDA1 itself, and here’s why that happens.
When you use an active DI box like the Samson MDA1, it contains a preamp circuit that needs power (from phantom power or a battery) to boost your guitar's signal. Lower-cost electronic components in this circuit can inherently generate a small amount of self-noise, which you hear as a constant hiss. This becomes more noticeable when you:
AI seems to agree the hiss is coming from the MDA1:
It seems like the MDA1, although it lowered the volume of the hum, it seemed to introduce a lot of hiss. Is that normal?
That's a very sharp observation, and you're not imagining things. It is a common and understandable trade-off, especially with entry-level gear. The hiss you're describing is likely circuit noise from the MDA1 itself, and here’s why that happens.
Why a DI Box Can Introduce Hiss
The table below breaks down the difference between the hum you were trying to fix and the hiss you're now hearing.[th]
[td]Hum / Buzz (Your original problem)[/td][td]A low-frequency drone (50/60 Hz) that stops when you touch the strings.[/td][td]Ground loops. The MDA1's ground lift is designed to fix this.[/td]
[td]Hiss / White Noise (Your new problem)[/td][td]A high-frequency "shhhhh" sound, like an old TV tuned to a dead channel.[/td][td]Electronic noise (hiss) generated by the preamp circuitry inside the active DI box itself.[/td]Type of Noise
[/th][th]What It Sounds Like
[/th][th]Common Cause
[/th]- Increase the Gain: To compensate for the signal level, you might have turned up the gain on your mixer's channel, which amplifies both your guitar and the DI box's internal noise.
- Use a Noisy Power Source: If the phantom power from your mixer is noisy, it can introduce noise into the DI box.
Is It Normal? For the MDA1, Unfortunately, Yes.
For budget-friendly active DI boxes, some amount of added hiss is a common compromise. You experienced a classic audio trade-off: you successfully traded a loud, annoying hum for a more subtle, but still present, hiss.The Solution: A Higher-Quality DI Box
This is exactly the reason why musicians upgrade to DI boxes from brands like Radial or Countryman. These units use higher-quality, lower-noise components and better power supply filtering specifically to minimize this kind of circuit hiss.- A Radial J48 (Active): Uses a very clean, switching power supply that is exceptionally quiet and has a high "signal-to-noise ratio," meaning you get more of your guitar's signal and less of the box's own noise.
- A Radial JDI (Passive): This is a fantastic alternative. Since it contains no active circuitry and is just a high-quality transformer, it generates zero hiss. It can't add noise that isn't there. It would solve the hum via its ground lift and would not add any new hiss.
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ecc83
Well-known member
My apologies! i cocked up the first download of that clip (i was fine with "Save Target As" Bloody microsoft!) Yes, the guitar is averaging around -18dBFS and peaking to some -6dBFS. That 60Hz hum is at -40 or so.
I cannot find a review of the Samson DI I trust. The various Amazon comments are totally useless! How can some find the box "very clean" and others "signal to noise ratio unacceptable"? I have to conclude that box IS marginal in its noise performance, something totally unforgivable these days. It cost next to bugger all more to make quiet electronics as hissy ones.
The Zed10 will not have noisy phantom power unless it is faulty in some way. I used one for years now son in France has it and has used it to record classical guitar which would expose the pimples on a flea's bum! The mixer should give very quiet results from its high Z line inputs but make sure the boost is not applied.
If the Zed is an older 16 bit model it is worth checking that attachment and ensure that the gain is reduced to about 5% even less. You then need to 'hit' the converters that bit harder. The hash is not removed but is push down to about -80dFS.
But, this is definitely a hum problem and I am now convinced the whole rig lacks a solid earth.
Dave.
I cannot find a review of the Samson DI I trust. The various Amazon comments are totally useless! How can some find the box "very clean" and others "signal to noise ratio unacceptable"? I have to conclude that box IS marginal in its noise performance, something totally unforgivable these days. It cost next to bugger all more to make quiet electronics as hissy ones.
The Zed10 will not have noisy phantom power unless it is faulty in some way. I used one for years now son in France has it and has used it to record classical guitar which would expose the pimples on a flea's bum! The mixer should give very quiet results from its high Z line inputs but make sure the boost is not applied.
If the Zed is an older 16 bit model it is worth checking that attachment and ensure that the gain is reduced to about 5% even less. You then need to 'hit' the converters that bit harder. The hash is not removed but is push down to about -80dFS.
But, this is definitely a hum problem and I am now convinced the whole rig lacks a solid earth.
Dave.
Attachments
MC208
New member
Not sure what you meant by (especially the bold part):
If the Zed is an older 16 bit model it is worth checking that attachment and ensure that the gain is reduced to about 5% even less. You then need to 'hit' the converters that bit harder. The hash is not removed but is push down to about -80dFS.
It is older, from 2012 is when we purchased it. I'm not so much worried about the input levels in the computer. If I can hear the hum/hiss at the mixer level, then it will of course be an issue in the computer as well. I forgot to mention that I included a Presonus Blue Tube, and that's where the Samson is getting its phantom power. I'll try taking the Bluetube out and use the ZED's phantom power and see if that gets rid of the hiss.
If the Zed is an older 16 bit model it is worth checking that attachment and ensure that the gain is reduced to about 5% even less. You then need to 'hit' the converters that bit harder. The hash is not removed but is push down to about -80dFS.
It is older, from 2012 is when we purchased it. I'm not so much worried about the input levels in the computer. If I can hear the hum/hiss at the mixer level, then it will of course be an issue in the computer as well. I forgot to mention that I included a Presonus Blue Tube, and that's where the Samson is getting its phantom power. I'll try taking the Bluetube out and use the ZED's phantom power and see if that gets rid of the hiss.
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ecc83
Well-known member
I am not sure of the exact mechanism but the old 16 bit converters in many brands of USB mixers had this problem. Windows defaults the "gain" for the input device at 100% and this results in the hash, similar to what we see in your spectra. The fix is to reduce input gain drastically in Windows Sound Control (as per the attachment) to 5% or less. The hash now drops to around -80dBFS but you have to increase the analogue drive to compensate. A&H fairly quickly fitted 24 bit converters which did not have the problem. We later in fact got a Soundcraft Notepad mixer which was 24 bits and very quiet.
Note, this is not a slight on 16 bit converters overall. There were and still are 16 bit devices that deliver close to the theoretical 96 dynamic range.
Dave.
MC208
New member
Level 5 wouldn't even be audible for the input level in windows?!? I have it at 76 as it is now...
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ecc83
Well-known member
Well have a bit of faith and try it! Naturally you have to crank up the analogue input level. I no longer have such a device to demonstrate the effect.
Dave.
MC208
New member
"crank up the analogue input level."
What do you mean? That's the only input level going into the computer.. I very infrequently record directly to the computer. We usually record straight to the camera. For Zoom calls, we use the USB out of the mixer though.
What do you mean? That's the only input level going into the computer.. I very infrequently record directly to the computer. We usually record straight to the camera. For Zoom calls, we use the USB out of the mixer though.
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ecc83
Well-known member
I am ONLY talking about the Zed 10 and its possible 16 bit shortcoming! My USB mic is nowhere near as noisy as I recall the Zed being. The 100% spectrum shows a spike at precisely 8kHz. Ideally that should not be there and is an artifact of the mic's converter I would say. The hum at -60dB is because I have the laptop on charge. Note it is at 100Hz, not mains at 50Hz.
The 6% spectrum shows that the 8kHz 'whine' has been subsumed into the noise floor. Hum as you can see is not at -100dB.
Do note! These decibel figure do not indicate the actual noise levels. Right Mark Analyser is not calibrated. Note too that even at 6% gain the mic still worked. I clapped my hands and got an indication. The optimum seem to be around 60%.
Dave.
The 6% spectrum shows that the 8kHz 'whine' has been subsumed into the noise floor. Hum as you can see is not at -100dB.
Do note! These decibel figure do not indicate the actual noise levels. Right Mark Analyser is not calibrated. Note too that even at 6% gain the mic still worked. I clapped my hands and got an indication. The optimum seem to be around 60%.
Dave.
Attachments
MC208
New member
You guys keep posting these images, I have no idea what they are.. I'm not as techy as you
rob aylestone
Moderator
The plots are not really 'techy' - they're just a left to right display of frequency, with amplitude on the vertical scale - 20-20K, the full audio spectrum. There is a hum at 100Hz, and another just above 150Hz - usual UK mains hum as was mentioned in the topic earlier is 50Hz, but the first harmonic of it is 100Hz. Learn to read these, they're really a good way to see what you are hearing.
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ecc83
Well-known member
Yes MC, do do a bit of reading! I know many people think "electronics" is a deep and mysterious subject but the basics are not, not really. My maths never got past simultaneous equations and I have long forgotten that! Ohms Law, the relationship between volts,amps and resistance is just the same equation as speed distance and time and we all learned that at school. Decibels are bit harder but if you did logs? In any case there are myriad calculators on line where you just 'plug in' a voltage ratio or a dBu number and get the result.
Graphs? SURELY you did graphs!!
Dave.
MC208
New member
I'm more practical I guess, just want to know how to fix the problem I got, and so far this direct box seems to be doing the trick, better than it was before. Perhaps we'll invest in a Radial if it's that much better.
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ecc83
Well-known member
I am very practical! Just coz I know a bit o theory don't make me useless! I would STILL like to know if you are totally confident that your whole recording chain is earthed and if you don't own a $20 digital multimeter bloody get one!
It is THE most valuable 'non musical' thing the recording musician can buy. The second is a sound level meter but a phone app is fine as well now.
Dave.
MC208
New member
I don't know what you mean by recording chain earthed. Everything is plugged into a rackmount Furman power conditioner, and then that's plugged into the wall. No I don't own a multimeter, wouldn't know what to do with it 
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ecc83
Well-known member
Chicken and egg sir. You won't know what to do with a meter until you get one. Suggestions! Test batteries, check earth continuity (we can tell you how) check the polarity of wall wart power supplies, been the ruination of many a gadget when that is wrong.I don't know what you mean by recording chain earthed. Everything is plugged into a rackmount Furman power conditioner, and then that's plugged into the wall. No I don't own a multimeter, wouldn't know what to do with it
Modern meters are sensitive enough and have a high enough input resistance that they can be used for signal tracing. Test cables!
Come on chap, this is the 21st century! This stuff is really not that hard for someone who can drive a car, use a bank account, follow a recipe?
AN another thing! I have just answered a question about phantom power and the possibility of it being on a jack 'combi' socket? A meter can test for that and possibly save you $$$$$s in a wrecked device.
Dave.
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rob aylestone
Moderator
ECC and MC are on different sides of a fence. I do understand both viewpoints, but the real issue here is that somebody has a problem, and the suggestions to fix it are being rejected.
MC's comment on not knowing what to do with it is a fair one I think. Many people just do not have the expertise to use a meter in any meaningful way? They might be cheap but making sense of readings is reliant on have knowledge. if you don't know what an Ohm is, let alone his Law, then the meter is pretty useless. The thing with audio, of course, is that it is event led. You get a hum. You work out it is mains related, so you buy a power conditioner - and then get frustrated when it doesn't do anything and it's a waste of money.
Curing hums in studios is part science, part magic - but the method of sorting it has to be methodical and structured. Many people ignore the advice, thinking they can solve it easier with extra bits, when the issue is nearly always to find that one bit of kit, or worse, the accidental combination of two bits of kit that hate each other - and fix it.
Hum sufferers who are struggling MUST disconnect absolutely everything. They must also feed all their audio gear from one power source - resisting the urge to use that handy outlet across the room. Who knows where it gets it's power? Plug in your 4 or 6 way gizmos, and start with your powered speakers, or speakers and the amp. No hum? Proceed to whatever will be sending sound to the speakers. Connect that - no hum? Proceed adding more kit, one by one. At some point the hum will appear. That will give you direction. You can always come back here and tell us what you did, step by step, and what bit of kit is the trouble. If you are not technical, draw a picture of every new addition and how you cabled it. We can help if we have data. We cannot without clarity and explanation.
MC's comment on not knowing what to do with it is a fair one I think. Many people just do not have the expertise to use a meter in any meaningful way? They might be cheap but making sense of readings is reliant on have knowledge. if you don't know what an Ohm is, let alone his Law, then the meter is pretty useless. The thing with audio, of course, is that it is event led. You get a hum. You work out it is mains related, so you buy a power conditioner - and then get frustrated when it doesn't do anything and it's a waste of money.
Curing hums in studios is part science, part magic - but the method of sorting it has to be methodical and structured. Many people ignore the advice, thinking they can solve it easier with extra bits, when the issue is nearly always to find that one bit of kit, or worse, the accidental combination of two bits of kit that hate each other - and fix it.
Hum sufferers who are struggling MUST disconnect absolutely everything. They must also feed all their audio gear from one power source - resisting the urge to use that handy outlet across the room. Who knows where it gets it's power? Plug in your 4 or 6 way gizmos, and start with your powered speakers, or speakers and the amp. No hum? Proceed to whatever will be sending sound to the speakers. Connect that - no hum? Proceed adding more kit, one by one. At some point the hum will appear. That will give you direction. You can always come back here and tell us what you did, step by step, and what bit of kit is the trouble. If you are not technical, draw a picture of every new addition and how you cabled it. We can help if we have data. We cannot without clarity and explanation.
MC208
New member
"Hum sufferers who are struggling MUST disconnect absolutely everything."
I did that if you recall. I unplugged everything, then I plugged the mixer into the wall, plugged the guitar into the mixer, and listened to the hum with headphones.
So with only the mixer plugged into the wall, and all other devices completely unplugged, including computers, lights, etc, the hum exists. Adding the Samson direct box decreased the volume of the hum. That's where I'm at.
I did that if you recall. I unplugged everything, then I plugged the mixer into the wall, plugged the guitar into the mixer, and listened to the hum with headphones.
So with only the mixer plugged into the wall, and all other devices completely unplugged, including computers, lights, etc, the hum exists. Adding the Samson direct box decreased the volume of the hum. That's where I'm at.