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Need to advice about noise on Mixer.

cheonmu

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Hello.

My store installed audio system but it was too noisy and I'm looking for a solution.

First of all, my system is


Computer > USB DAC > Mixer > EQ > XO > Bai-Amplifier > Speakers

And I using Spirits live 4 mixer.


The reason that mixer is thought to be the cause is that if i playing using CDP directly without going through mixer, there is no noise.

even if I test except for crossover, going through the mixer still makes a lot of noise.

My mixer panel looks like below, but most of them are using the default value (0).


112312312411.jpg


Are there any settings on this mixer that have noise and effects?

I'd like to hear your advice. thank you.
 

JayGilb

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Are you hearing a low frequency hum or a hissing type of sound ?
If you are hearing a LF hum, then check to see if you can run balanced cables between the DAC and mixer.

If you are hearing a hissing sound then you can experiment with some gain staging. You have many options to control the gain between
the DAC and the amp. Try lowering the gain knob on the individual tracks where you connecting the DAC to the line input.
I would probably set the volume on your PC to 100% and use the Main Left/Right sliders on your mixer to control the volume.

Make sure your eq is adjusted to a "flat" setting and any additional gain settings on the EQ are set to 0.
 

AnalogSteph

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Please specify types of all of
USB DAC > Mixer > EQ > XO > Bai-Amplifier
and type of cables used between them, along with any input / output gain control settings on the last 3.

This type of PA mixer would have been operated by trained professionals back in its day. If you have some prior experience operating a typical compact portable mixer (Behringer, Mackie, whatever), you should be able to figure it out using the manual (including studying the block diagram), but if you don't you may be in for a bit of a learning curve indeed.

Also, being an old PA mixer, it's not exactly the last word in noise, so proper gain staging will have to be observed. If the other equipment is similarly dated, Pin 1 Problem issues may also crop up.

My plan of action:
1. I would suggest using one of the stereo input pairs provided for simplicity's sake. If you USB DAC will output +8 dBu or less, engage the "-10" switch (which increases input sensitivity to consumer line level).
2. Make sure that all unused inputs are turned down.
3. The MASTER fader will be your main volume control. For normal listening levels, it should be at around -30 dB, maybe -40 (sort of depends on whether volume normalization like ReplayGain or similar is in use). Otherwise gains downstream may need adjusting.

Why this awfully complex setup anyway? EQ is perhaps best handled in the digital domain today, for example.
 
OP
C

cheonmu

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Are you hearing a low frequency hum or a hissing type of sound ?
If you are hearing a LF hum, then check to see if you can run balanced cables between the DAC and mixer.

If you are hearing a hissing sound then you can experiment with some gain staging. You have many options to control the gain between
the DAC and the amp. Try lowering the gain knob on the individual tracks where you connecting the DAC to the line input.
I would probably set the volume on your PC to 100% and use the Main Left/Right sliders on your mixer to control the volume.

Make sure your eq is adjusted to a "flat" setting and any additional gain settings on the EQ are set to 0.


Hi, Jaygilb

Thanks for answering.
I'm not an audio expert, so I couldn't tell that what kind of noise.

So I've been recording noise!


https://soundcloud.com/junuk-seo%2Fkakaotalk-audio-20220104-1753-44-399
This was recorded with aders of the input and output set to 0 and recorded about 30 cm in front of the speaker.

i am using RCA to TRS cable from DAC to Mixer.

And i tried replacing it with a CDP cable, but it was not a problem with the cable.

all of my settings that could affect the output of the sound set to 0. (EQ, XO, MIXER) Only volume of Laptop and Amps are Maximum.


Can you tell me what I can check again?

Thank you and Happy new year!
 
OP
C

cheonmu

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Please specify types of all of

and type of cables used between them, along with any input / output gain control settings on the last 3.

This type of PA mixer would have been operated by trained professionals back in its day. If you have some prior experience operating a typical compact portable mixer (Behringer, Mackie, whatever), you should be able to figure it out using the manual (including studying the block diagram), but if you don't you may be in for a bit of a learning curve indeed.

Also, being an old PA mixer, it's not exactly the last word in noise, so proper gain staging will have to be observed. If the other equipment is similarly dated, Pin 1 Problem issues may also crop up.

My plan of action:
1. I would suggest using one of the stereo input pairs provided for simplicity's sake. If you USB DAC will output +8 dBu or less, engage the "-10" switch (which increases input sensitivity to consumer line level).
2. Make sure that all unused inputs are turned down.
3. The MASTER fader will be your main volume control. For normal listening levels, it should be at around -30 dB, maybe -40 (sort of depends on whether volume normalization like ReplayGain or similar is in use). Otherwise gains downstream may need adjusting.

Why this awfully complex setup anyway? EQ is perhaps best handled in the digital domain today, for example.
Hi, AnalogSteph

Thanks for your detailed answer!

I am using below audio eqipmenets.

Toppin E-30 (USB-DAC)
Spirits live 4 (Mixer)
DOD SR231Q Graphic EQ
Peavey V4X ELECTRONIC CROSSOVER
Several amps maded by S.Korea
JBL Speakers

I use RCA to TRS cable from DAC to Mixer and all others use TRS or XLR cables (Blanced).

Also i am not using Stereo as Input. I am using input and output like the screenshot below.

MIx.jpg



The EQ and XO gain(level) are set to 0, and the amp is set to maximum output.

XO is controlled frequency as 2 way (MF, HF).

====================================

1.
Output of DAC (E30) is set to 0 dB by default. - dB is possible, but + dB is not possible.

I was turned on "Line -20dB button" becasue if not enabled that no sound.

Will enabling this button affect the noise?


2. All of unused input channel was disabled already.


3. -30 or -40dB is too low volume for me.

However, if i set it to -30 or -40db, there is still noise, but it can be minimized.

So, as a temporary measure, I raise the input gain to about 20, set the input fade to 0, and set the output fade to -30db.

But still the noise is not resolved.


4. I run a dance salon, and I bought all of these systems in bulk from another closed salon.

And even though the broken amplifier and woofer have been repaired,
noise of the speaker still has not been resolved.

I don't want to use such a complicated system, but there are different Woofer and Tweeter Units from different manufacturers.

So, I have no choice but to use it to keep the relatively identical output.

==============

I'm sorry my English is not good.

But I really want some advice. and happy new year!
 

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AnalogSteph

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So let me get this straight: The mixer is being used as nothing more than a glorified 2-channel volume control?

I was turned on "Line -20dB button" becasue if not enabled that no sound.

Will enabling this button affect the noise?
The labeling of this one is a bit misleading - what they meant was "LINE (-20 dB)". So it indicates
1. that this is how you enable the line input (as you found out) and
2. that there is 20 dB worth of input attenuation for LINE, so that the input can handle up to +30 dBu.

With +20 dB of input gain you are on the right track. You could probably go to +30 dB still, which should give a 0 dBFS level of +18 dBu on the mix bus.

If that still doesn't get the noise level in check to a satisfactory degree, I would suggest trading in the E30 + mixer for a USB audio interface, plus some TRS --> XLR cables. Maybe a Focusrite Scarlett Solo or 2i2 3rd gen (up to +15.5 dBu out) or Tascam US-2x2HR (up to +18 dBu out, with enough gain to clip the output stage on 0 dBFS if turned all the way up). Those should be similar to the E30 price wise. Alternatively, the mixer could be replaced by a basic monitor controller.

The audio interface route would also enable you to use an XLR measurement microphone with e.g. REW or ARTA to fine-tune the crossover and come up with settings for software EQ, so that the DOD could possibly be eliminated as well. (If you already have a good-sounding condenser microphone at hand, that would be a great start!)

It may be useful to write down the settings of the V4X, input level of power amps and driver types, just to rule out nonsensical combinations.
 

JayGilb

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So let me get this straight: The mixer is being used as nothing more than a glorified 2-channel volume control?
That's the conclusion I arrived at.

It's installed in a store, which is a pretty vague description and without more details, I'm not sure I would recommend additional hardware.
 

raindance

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It probably has the gain and faders cranked up for all the unused channels.
 

AnalogSteph

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It probably has the gain and faders cranked up for all the unused channels.
I specifically wrote
2. Make sure that all unused inputs are turned down.
to rule out just that. We can't know for sure without looking at a photo of the thing, of course.

Keep in mind it's an older PA mixer, so I won't be too surprised if it isn't the last word in noise.

It's installed in a store, which is a pretty vague description and without more details, I'm not sure I would recommend additional hardware.
The OP wrote "dance salon", which I presume is a disco.
 

JayGilb

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I specifically wrote

to rule out just that. We can't know for sure without looking at a photo of the thing, of course.

Keep in mind it's an older PA mixer, so I won't be too surprised if it isn't the last word in noise.


The OP wrote "dance salon", which I presume is a disco.
I missed that.
A quick search shows it probably is a dance school.
 
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