Soundcraft EPM6 mixer high signal input level and strange gain control range

[djtetei]

I have two DJ mixing consoles, a Denon MCX 8000 and a Reloop RMX 60, and I want to connect their balanced XLR master outputs to a Soundcraft EPM6 mixer, using the latter stereo balanced TRS inputs.
The Soundcraft EPM6 has 6 mono channels, where you can connect microphones (via XLR inputs) and line level sources (via the balanced TRS jack inputs), and 2 stereo channels with balanced TRS jack inputs for the left and right channels.
No matter which TRS input I use on the EPM6 mixer to connect the RMX 60 balanced outputs, the input signal level on the EPM6 is abnormally high (hitting the 0 dB mark on the EPM6 meters in PFL mode), even with the gains fully down at -10 dB, the channel faders at 0 dB and the main mix faders at 0 dB. Actually, on the mono channels TRS inputs the signal is even higher, hitting +9 on the level meters, with the input gains at the minimum.
The connections are made with Cordial CFM FV XLR female to TRS cables.
If, on the other hand, I connect the RMX 60 unbalanced RCA master outputs to the EPM6 stereo inputs, using RCA to TS cables, the input signal levels are normal.
The Reloop RMX 60 master output impedance is 600 ohms and the nominal output levels are 0 dBV, both on balanced and unbalanced outputs.
If i connect the Denon MCX 8000 balanced XLR outputs to either of the EPM 6 stereo inputs, the input signal level is normal and I can set the EPM 6 mixer input gain knob to the imaginary 0 dB position.
Denon MCX 8000 master nominal output level is +4 dBU.
If I remove the EPM 6 mixer from the signal chain and connect either the Denon MCX 8000 or the Reloop RMX 60 balanced outputs to the Behringer FBQ 6200 HD inputs, the signal levels are normal, hitting 0 dB on the FBQ 6200 HD level meters with the gains set at 0 dB.

[Wonks]

Hi and welcome.

This is a very strange one.

Just a couple of things to note. As you are looking at the PFL signal value, neither the channel faders or main mix faders will have any effect on the signal level shown. If you look at the signal flow schematic on page 17 of the online EFX/EPM manual you'll see you are routing the signal from after the EQ section straight to the meters, so it's only the channel gain and the EQ that affect the signal level reading.

As the PFL metering sums the two input channels together, the PFL reading will show a value that's 3dB higher than if you looked at the output meter with no PFL and the channel fader and master fader set at 0.

Do you have the stereo channel EQ flat when checking, as boosting either treble or bass will increase the indicated input signal level?

I suspect that the 0dBv output level in the manual for the Reloop RMX 60 may be more nominal than maximum. 0dBV equates to 2.2dBu into the Spirit's 65k stereo line inputs. As they can take a nominal +30dBu signal before overloading, there should be plenty of headroom available for hotter signals. For example, the Denon shows an extra 20 dBu available on its outputs over the nominal +4dBU at unity.

The Behringer EQ's inputs have a 40k input impedance, so it's not like there is a big difference in impedance at 40k vs 65k. If there was, then the signal level difference could be down to the design of the Reloop output drivers being able to pass a higher voltage into a higher impedance as there would be less current loading, but this can't be the case here.

Presumably by turning the master volume down on the Reloop RMX 60 you can get a lower PFL signal level that isn't pushing 0dB on the meter? If that works, is that an issue?

[djtetei]

The PFL active level is the same as the Main Mix level on the meters.
The High and Low frequencies equalisers are set to 0 dB attenuation (center position).
Regarding the master output level on the RMX 60, yes, I can lower the output level on the RMX 60 side, but this means not to drive the RMX master outputs at nominal output. This is not normal behaviour, because I have to have nominal output and input levels throughout the signal chain. Furthermore, the EPM mixer gain controls should be able to manage various sources levels.
As I mentioned earlier, the RMX 60 puts out the same 0 dBV nominal output level on unbalanced outputs also and when I use the RCA to TS cables on the EPM 6 stereo inputs, the input level is normal and easier to control with the gain knobs. In fact the the unbalanced input level on EPM 6 is right on the money, 0 dB on the meters, with all controls zeroed.
The strange thing is that the Soundcraft EPM6 specifications doesn't state any nominal input or output levels. My assumptions are based on the fact that, at least for the main mix output levels Soundcraft adheres to the +4 dBU nominal level as stated by them in their "Soundcraft Guide to mixing" paperwork. Based on their own documentation, the stereo input nominal level should be at least 0 dBU and +4 dBU ideal.
The same user manual states that the main mix output level is +20 dBU, wile the EPM series brochure states +22 dBU headroom throughout the the console.

[Wonks]

The PFL active level is the same as the Main Mix level on the meters.

The they must have added in some attenuation on the PFL feed. They don't show everything in the signal flow schematics. But OK, the PFL and main meters read the same values, that's fine.

Regarding the master output level on the RMX 60, yes, I can lower the output level on the RMX 60 side, but this means not to drive the RMX master outputs at nominal output. This is not normal behaviour, because I have to have nominal output and input levels throughout the signal chain.

There is no 'normal behaviour'. Interfacing different equipment involves adjusting sent signal levels to get the right match for the input device. Once you stop thinking that everything is best if set to 'nominal' signal levels, then things become easier. It's all about sending the right strength signal from one device so it works with the device that's receiving the signal. It may involve turning the output volume down or up to do that.

Furthermore, the EPM mixer gain controls should be able to manage various sources levels.

It does. It has an input gain range of -10 to +20dB. A lot of line-only inputs on mixers don't have any input gain control at all. So you've got 30dB of gain adjustment. But it's obvioulsy not expecting a signal as hot as the RMX 60 is sending.

As I mentioned earlier, the RMX 60 puts out the same 0 dBV nominal output level on unbalanced outputs also and when I use the RCA to TS cables on the EPM 6 stereo inputs, the input level is normal and easier to control with the gain knobs. In fact the the unbalanced input level on EPM 6 is right on the money, 0 dB on the meters, with all controls zeroed.

You are making that assumption based on the figures in the manual. But a lot of manuals have errors in the specifications section. The only way you actually know what the signal level is is by measuring it.

As the Soundcraft mixer meters show that the signal is hotter when coming from the balanced rather than the unbalanced outputs, then it would seem the figure in the manual for the balanced output is incorrect and the nominal output level is much greater.

The strange thing is that the Soundcraft EPM6 specifications doesn't state any nominal input or output levels. My assumptions are based on the fact that, at least for the main mix output levels Soundcraft adheres to the +4 dBU nominal level as stated by them in their "Soundcraft Guide to mixing" paperwork. Based on their own documentation, the stereo input nominal level should be at least 0 dBU and +4 dBU ideal.
The same user manual states that the main mix output level is +20 dBU, wile the EPM series brochure states +22 dBU headroom throughout the the console.

Welcome to the real world of mixers. Nominal levels are just that and indicate the general sort of signal level you expect to be fed into, or come from the equipment in question. Basic levels in music technology are mic level, instrument level and line level. But within those categories, the actual signal strengths can vary considerably.

What is more important for a mixer is knowing the maximum signal levels the mixer can accept or output, and for the inputs, what amount of of gain adjustment control you have. It's all about available headroom and working within that headroom. Which is why a 'nominal' value for an input or output is meaningless. You simply want to get a reasonable signal level going into a mixer.

With a loud signal, you may be able to lower the level enough on the channel gain control for it to be happy, but you may need to turn the input signal level down on the output device if you don't have enough attenuation available.

With a quiet signal, if you can't turn up the signal strength any more on the output device, then you use the gain control on the mixer to get a decent signal level going into the channel. It may sometimes be necessary with very quiet signals to feed the signal into a mic input, not a line input so that more gain is available.

In this instance, turning the output volume down on the RMX 60 is the right thing to do to get the right strength signal fed into the EPM.

I have no idea why you seem to get a lower signal level when feeding into the Behringer EQ. But turning down the RMX 60 output is not bad or detrimental to the sound when using the EPM 6.

[djtetei]

Reloop RMX 60 official master output levels, published in the user manual:

• unbalanced: 0 dBV

• balanced: 0 dBV

Reloop RMX 60, real life, measured master output levels:

• unbalanced: 0 dBU (0.77 V)

• balanced: +4 dBU (1.23 V)

This still doesn't explain the high signal input level on the EPM6, with the gain set to -10 dB.

[Drew Stephenson]

Are you sure on your units there? dBu = dBV + 2.21

[Wonks]

No, it doesn't. The answer will probably lie within the RMX 60.

I presume the measured values were obtained from someone else or a post on another forum rather than you measuring the output yourself?

Maybe some wrong resistor values were used to set the balanced output op-amp gain and as a result it is hotter than it should be. Or maybe an alternative op-amp was used which has a higher gain than the original item. I'm just purely guessing here. You'd need to take your mixer apart and follow the signal path through and check what the signal levels were at various parts of the circuit and if they differed much after being split to go to the unbalanced and balanced output drivers.

If it was just the balanced outputs you'd connected, it could well be down to the meter circuit parameters and calibration differences between the two units. Unlike a digital peak meter, analogue signal meters will rarely read the same value given the same music signal. They are normally short-term RMS peak meters and there will be differences in the time period each meter uses for the meter display average. The only way to properly check the calibration is with a constant level signal, normally a 1kHz sine wave.

But if there is a big difference between the unbalanced output level and the balanced output level with the same RMX 60 meter reading as shown n the EPM6 meter, then (by my reasoning) it can only be the output level on your particular RMX 60 unit that's varying. You've said the Denon output into the same inputs gives the correct results, so it logically can't be the EPM 6 input circuitry, therefore it must be the RMX 60's balanced outputs.

You could take the RMX 60 back to where you bought it and try comparing it with another unit, but as the output level difference between spec and actual may only be 10dB or so, it is something you could easily live with by turning down the output volume on the RMX 60.

I'm all out of new ideas, so I hope you manage to work something out.

[Wonks]

Are you sure on your units there? dBu = dBV + 2.21

The quoted dBu figures are correct for the stated voltages. It's just that whoever did the measurement used dBu rather then the manufacturer's dBV units.

Converting them all to dBV, we get

Unbalanced output: 0dBV stated, -2.22dbV measured

Balanced output: 0dBV stated, 1.78dbV measured

So, a discrepancy in each case, but not a major one. And without knowing exactly how each value was derived e.g. signal type and frequency, the discrepancy may be smaller or larger than stated.

[Drew Stephenson]

Are you sure on your units there? dBu = dBV + 2.21

The quoted dBu figures are correct for the stated voltages. It's just that whoever did the measurement used dBu rather then the manufacturer's dBV units.

Converting them all to dBV, we get

Unbalanced output: 0dBV stated, -2.22dbV measured

Balanced output: 0dBV stated, 1.78dbV measured

So, a discrepancy in each case, but not a major one. And without knowing exactly how each value was derived e.g. signal type and frequency, the discrepancy may be smaller or larger than stated.

I'll take your word as to the impact! Just checking we didn't have any red herrings in the mix.

[Hugh Robjohns]

It seems to me that this 'issue' can be resolved simply by adjusting the master output level on the DJ console. It's why it's there, after all!

In my limited experience of DJ consoles, they often have very hot outputs largely because commercial digital media still tends to peak close to 0dBFS, and the D-A conversion to balanced outputs is typically set up to translate that to ultra-hot analogue levels circa +24dBu.

In contrast, a traditional analogue console with a nominal operating level of +4dBu would expect peaks around +12dBu... so its not really surprising that you need to attenuate the signal by 12dB or more.

The only oddity is the claim that both DJ consoles register nominal zero levels when connected to the Behringer graphic. However, that unit features a limiter which could be reducing any source level discrepancy and thus be misleading.

Impedances are irrelevant to the discussion. These are matched-voltage interfaces and the equipment input impedances are all more than 10x the source output impedances, which is the only requirement.

And the quoted signal levels are just a confusing mess of nominal and peak levels referred to different standards.

I'd just turn the loud decks down a bit.....

[djtetei]

The only oddity is the claim that both DJ consoles register nominal zero levels when connected to the Behringer graphic. However, that unit features a limiter which could be reducing any source level discrepancy and thus be misleading.

Both the equaliser and the crossover have built-in limiters, but they are not engaged.

[AlecSp]

I'd be more pragmatic than Hugh. Does it sound bad? If not, then there's no problem.

Even if there is a problem, then Hugh's bang on the money in that you can just turn down the output from the DJ mixer.

In this game, practical expediency trumps theoretical navel gazing every time.

[djtetei]

Thank you very much indeed, all of you, for your help.
Yes, lowering the RMX 60 master output level is logical, but I had to confirm there is nothing wrong with the Soundcraft EPM6 gain control and, indeed, Soundcraft support staff confirmed the EPM6 behaviour as being normal.

I checked a Soundcraft Ui12, which has a normal 600 Ohm symmetrical output (like your Reloop), and I connected it with the service EPM6.

Indeed, if the Ui is set to the usual -9dB average signal level, with the gain control completely turned down, we have an average signal level of 0dB on the analog console.

So we can say that everything is working fine.

If this is not good for you, you need to gain back the Reloop if you want to control the signal level on the EPM.

I hope this helps.

Best regards,

Technical Support Engineer EMEA
Harman Professional Solutions

Removed engineer's name from the quoted response --ED.

[resistorman]

To paraphrase Mark Twain: there are lies, damn lies, and specifications

[djtetei]

What can I say, it is the world we live in...
And speaking about lies, the Soundcraft technical engineer mentioned in his reply that he used a Soundcraft UI 12 mixer as a source, because it had a 600 ohm output impedance, but the user manual technical specifications for UI 12 states that all its outputs have an impedance of 100 ohm.
I still have an issue with the EPM 6 stereo input stage, because any mixer should mention a nominal working level for the input stage to allow the user to assess which sources output levels can connect without overloading the mixer input stage (suppose one may use a DAC with no built-in preamplifier).
Take the Soundcraft EPM6 as an example: its stereo input stage gain range is between -10 dB and +20 dB, meaning that, inside this range, should be a unity gain point, where the input signal is neither boosted or attenuated. The EPM 6 inputs don't have the unity gain point clearly marked on the scale.

[Hugh Robjohns]

And speaking about lies, the Soundcraft technical engineer mentioned in his reply that he used a Soundcraft UI 12 mixer as a source, because it had a 600 ohm output impedance, but the user manual technical specifications for UI 12 states that all its outputs have an impedance of 100 ohm.

I think confused or mis-remembered, or even misunderstood* rather than lies.... Let's be kind rather than accusative, eh?

*Some tech support engineers talk of 600 Ohm symmetrical outputs, meaning balanced outputs with sufficient drive available to cope with an old-school 600 Ohm terminated input. It's an outdated concept, but a traditional mark of a professional-standard balanced output.

But as I explained above, it wouldn't matter if the output impedance was 100 Ohms, 600 Ohms, or even 1000 Ohms. With everything receiving the DJ console's output having an input impedance of 10K Ohms or more (much more, in most cases), the signal voltage /signal level would not be affected in any relevant way. Impedance is almost always irrelevant when discussing modern balanced connections.

I still have an issue with the EPM 6 stereo input stage, because any mixer should mention a nominal working level for the input stage to allow the user to assess which sources output levels can connect without overloading the mixer input stage

I wish published tech specs were generally more comprehensive too... but this is a £250 mixer intended for amateur and non-technical musicians. Some simplification cherry-picking of impressive numbers, and omissions are not surprising

However, the specs do state the maximum input level to the stereo input as +30dBu. And it's reasonable to assume the nominal operating level is +4dBu based on Soundcraft's history and other products.

Take the Soundcraft EPM6 as an example: its stereo input stage gain range is between -10 dB and +20 dB, meaning that, inside this range, should be a unity gain point, where the input signal is neither boosted or attenuated. The EPM 6 inputs don't have the unity gain point clearly marked on the scale.

A definitive mark would be nice, I agree, but I'd try the 12 o'clock position as a reasonable presumption, based on history and other products... and the default control positions shown in the manual.

If confirmation of unity gain is critical it's easy to test the desk to confirm the required knob position given a DAW and interface... amongst other techniques. If you need guidance let me know and I'll take you through it.

[djtetei]

A definitive mark would be nice, I agree, but I'd try the 12 o'clock position as a reasonable presumption, based on history and other products... and the default control positions shown in the manual.

Actually, except for the Soundcraft Notepad series or other models with simetrical positive and negative gain control, where the 0 dB point would be at 12 o'clock position, all other Soundcraft mixers tend to have the 0 dB attenuation point around 11 o'clock position, which, I suppose, it is the case with the EPM 6 mixer too.
If I were to use this point as a guide and feed the Reloop RMX 60 balanced master output nominal level (0 dB lon the the meters) to the EPM6 balanced stereo inputs, the PFL input signal level is hitting +10 dB on the EPM6 level meters, and +6 dB on the Behringer FBQ 6200 HD level meters, which is high for mastered music.
In my opinion, it may have something to do with the EPM 6 stereo input sensitivity (nominal level) being to high, even with -10 dB gain attenuation.
It seems like it has been designed for sources with low output level, like consumer devices with -10 dBV nominal output levels.

but this is a £250 mixer intended for amateur and non-technical musicians. Some simplification cherry-picking of impressive numbers, and omissions are not surprising

How expensive a piece of equipment, like a mixer, has to be in order to provide accurate and derailed technical specifications?
It doesn't matter if it's a mixer designed for amateurs or musicians lacking technical knowledge, the manufacturer has to provide all the relevant and necessary informations about its technical specifications in order to ensure safe and optimal operation inside the designed parameters.
If a musician or an amateur user lack the technical knowledge to operate a microphone, an instrument, a mixer, an amplifier or any other audio equipment he or she should read more and absorb the required technical knowledge to operate such equipments, or leave it to the sound engineers or other qualified people.
Furthermore, what is the point of buying a 32 channels mixing console, which is heavy, not portable and requires a lot of space, when all it may be needed is a mixer with no more than 2 mono inputs and 2 stereo inputs, able to support balanced input and output connections, with good electronics, sturdy knobs and faders and accurate meters?

[Hugh Robjohns]

You may be right.

[djtetei]

Here's another strange fact about Soundcraft support staff ability to provide clear answers to pertinent questions.

I asked the following:

"I understand your recommendation to lower the master output level on the Reloop RMX 60, but there is something that doesn't add up regarding the Soundcraft EPM6 stereo input gain control, unless it has something to do with the EPM 6 nominal input level (sensitivity). The EPM6 adjustable gain range is from -10 dB to +20 dB, meaning that somewhere inside this range there has to be a 0 dB point (I suppose it is at around 11 o'clock position), called unity gain, where the input signal is neither boosted or attenuated, so that what comes in it is equal to what comes out.
Can you confirm this?
If I am correct in my assumption about the 0 dB point position, would you, please, explain why on this position, the input signal is hitting +10 dB on the EPM6 level meters, wile the Reloop RMX 60 master output registers 0 dB on its level meters on balanced connection?
What is the nominal input level of the EPM 6 stereo input on balanced connection?
What is the main mix nominal output level (0 dB on the meters) on the EPM6 mixer?
I have read al the manuals for the Soundcraft EPM/EFX series and other Soundcraft mixers and I never found anything about nominal input and output levels in the technical specifications or in the operating instructions."

Soundcraft support staff reply:

"I can only refer to our own documents, which you can find at the links below:
https://www.soundcraft.com/en/product_d ... eb0f8cf6ce
https://www.soundcraft.com/en/product_d ... c80a9b1319
With gain, the goal is to achieve the necessary, appropriate signal/noise ratio, which is easily can be achieved with this mixer and your Reloop unit.
I'm sorry I could not send you the exact dB data.

Have a great day."

Even their own support staff couldn't provide a clear answer about their own product capabilities and specifications.
It's like they don't know what they're selling.

Let's pay attention to what they say in the Soundcraft EPM6 mixer description which states that the mixer "provides a stunning +22dB headroom through the console."
According to the EPM 6 technical data sheet, the main mix maximum output level is +20 dBU.
This would mean that the nominal output level (0 dB on the meters) of the EPM 6 master output is -2 dBU or 0.615 V RMS, which is 6 dB lower than the standard +4 dBU nominal level for professional equipment.

Next, I asked the Soundcraft support staff if they are able, at least, to confirm if the 0 dB nominal level on the EPM6 level meters is referenced to +4 dBU (1.23 V RMS) standard for professional audio equipment.
I am waiting for Soundcraft to answer.

[Wonks]

For a start, see my previous comments on meter calibration. You need to check with a 1kHz sine wave before you can make any judgement on relative meter calibration. You are using different manufacturers meters to get your nominal 0dB output level, so unless you are using a 1kHz sine wave, your readings are technically very vague. There is no 'standard' meter design with regard to non-constant signals and the integration period used.

I have no idea what signals you are using to get your meter readings so can't comment on the various meter readings you see.

Support staff are not the designers. They probably only have access to very similar documentation that you do. You'll find a very similar knowledge level across support staff from all manufacturers, (probably less from the lower-end suppliers). This is not a 10000€ console where the people you speak to are probably the designers and can tell you everything.

You are getting obsessed by nominal levels. All they really tell you is if a signal is roughly at mic, instrument or line level. Again, these nominal levels are exactly that, nominal (and will vary in reality from manufacturer to manufacturer).

If you were mixing a band, with a much much more expensive mixer like a Digico Quantum, you simply wouldn't give a thought to 'nominal' levels. Your job would be to adjust the input gain to get the right signal level going through the console for each input. If you need to get an input signal level turned down externally, you'd either do it at source if you could, or if that was not possible, switch to using a DI box (to drop to a mic level signal) or use an inline signal attenuator. You don't give a thought to whether the input signal is near a nominal level.

You'll get to know know if an input is line or mic level (you'll rarely get instrument levels on live gigs) and put the signal into an appropriate input and deal with it with the gain control.

If the headroom within the mixer is stated as +22dBu within the mixer, then that will be the headroom within the mixer. It is headroom, so allows the occasional very hot signal peak to be passed through without clipping. Output level is something very different and the signal going through the console may well be attenuated before hitting the output fader.

You are adding a number of input signals together within the mixer, so the signal will get hotter and hotter, especially on large mixers with a high channel count. So whilst the individual channel signal level in the mixer may well be near the 0dBu level, as you progress through groups (if the mixer has them) to the main mix.

So that +22dB headroom makes 0dBu read 0 on the meter, not -2. But again, you need the right input signal to check the meter. Why would you want +4dBu to read 0? You have a gain control to adjust the signal level (within limits) to what you want, and a channel fader.

You have +22dBU of headroom in the mixer, so what does it matter if the signal is coming in at +6dBu or -2dBu. You adjust if, and if it's still a bit hot, you just set the channel output fader lower. This is real-world mixing and all that a pro mixer is worried about.

Amps (and active speakers) will not like to be hit with a ridiculously hot signal, so there's no point having an output that is designed to hit them all the time with a really hot signal. You are probably talking between 0dBU and 8dBU max on average, so 20dBu allows for the odd peak spike whilst still leaving enough headroom not to to cause clipping.

Just drop all this nominal signal level stuff, as it really isn't important. Real-life signal levels vary. If the signal levels always matched exactly, you wouldn't need output level or input gain controls except for the channel and master faders on the mixer.

[Hugh Robjohns]

Here's another strange fact about Soundcraft support staff ability to provide clear answers to pertinent questions.

I appreciate your frustrations, but you seem to be expecting Rolls Royce standards of service when you bought a Reliant Robin... As the support agent said, he only has access to the same published info you have. It's not great, but at least you got to speak to someone. If you're nice to them they might go and ask someone who really knows for you....

... please, explain why on this position, the input signal is hitting +10 dB on the EPM6 level meters, wile the Reloop RMX 60 master output registers 0 dB on its level meters on balanced connection?

First, as Wonks said above, unless you're testing meter levels with steady sine tones all bets are off. Meter dynamics can vary wildly on audio material.

If you are using a sine tone, the difference in meter readings simply indicates different nominal operating levels between the two devices and/or unwanted gain being introduced in the mixer input.

The simple and obvious solution is to turn down the mixer input gain or the dj console master output level, or both. These controls are provided specifically for that purpose — to match the output level of the source to the input level of the destination. This is gain staging 101. Who cares where the knob is pointing?

Let's pay attention to what they say in the Soundcraft EPM6 mixer description which states that the mixer "provides a stunning +22dB headroom through the console." According to the EPM 6 technical data sheet, the main mix maximum output level is +20 dBU.

This would mean that the nominal output level (0 dB on the meters) of the EPM 6 master output is -2 dBU...

No, it doesn't.

First, you're assuming the maximum output level is the same as the internal clipping level. Depending on the output driver configuration this may not be the case. It could be as much as 6dB lower...

However, ~if~ the internal clipping level really is +20dBu, and there is 22dB of internal headroom, that would imply an internal operating level inside the desk of -2dBu, which is actually a very common figure. If there are any insert points they will also operate at this level.

This 'depressed' internal operating level is commonly chosen to maximise headroom through the channel preamp, EQ and mix bus stages to accommodate uncontrolled input signals without overload. Most mixers, even high-end professional models, use the same approach for the same reasons.

It is expected that these uncontrolled input signals will be suitably managed and mixed to a smaller dynamic range at the output, which can therefore operate with less headroom — at least in a budget product like this. It's a cost-effective but practical compromise.

And second, the meter zero is always calibrated to indicate the rated operating level at the desk's output connectors. It's probably +4dBu, although it could be 0dBu (Mackie mixers are calibrated for meter zero=0dBu, for example). The meter zero certainly does NOT indicate the depressed internal operating level. That would make no sense at all.

I have to say, much as I'm a technical geek that likes to align things accurately, I'm really struggling to understand the problem here. The two units have different operating levels. It's not unusual. If you want the mixer meters to match the dj console meters just adjust the output level/input gain as necessary. Job done.