Allen & heath all day long I'm running a Zed-420 in home studio, tried many well known makes out there and the Zed range are great sounding units as confirmed in sound on sound magazine + about to purchase a smaller Allen & Heath Zed to go with yamaha DSR115 for a live rig ...bang for buck you won't go wrong here which ever size Zed mixer you go for.

So now I understand this. I always thought "gain" was just a signal amplification but not that it had to match the incoming signal voltage. Here's my gain dial on my Allen & Heath ZED mixer. So once I match this dial reading to the Montage output selection then I'm at the optimum voltage level for the least amount of noise?

@David - I would suggest using the mixer's meters or clip light to set the input gain. On the edge of clipping is where these should be set. For the clip lights - since it's a warning light just before clipping occurs - it's generally OK to have the light illuminate every now and then. Constantly on is a problem and constantly off is likely having the gain set too low.

For example: Is it possible that the Montage could be set to 0dB output and then the mixer gain on that channel be turned up to +12dB and the clipping light not yeild any warnings? Isn't the 0dB of the Montage supposed to match 0dB on the mixer's gain dial as you all have described it? The volume control of the Montage also changes the mixer's meter level. Gain and volume are not the same obviously. Gain is equipment specific as I'm understanding it. 4 different synths hooked to the same mixer might have 4 different gain settings because each of the synth's dB nominal output voltages could all be different, correct?

Or does the meter graphically display the real time relationship between the dB level coming from the synth and the mixer gain knob? I thought the objective was to separate the noise in the "basement" from the top story. Volume level changes the fixed relationship between the gain and the incoming dB signal when those are set as matching one another.

Hello - the XENYX 1202FX is now installed- I have never seen so many knobs packed into so small a space! Literally a forest of them! I've mounted it vertically to avoid having to crane over it all the time, which meant having to arrange a rail to keep all the front-entry leads from getting in the way. It also has 2 buses, which is useful as I can keep the Korg/Tyros (unbalanced) inputs on one, and whatever else on the other (so far nothing!). Still playing with it, but I did try switching the gain from -10dB to +4dB for the Korg/Tyros bus - no discernible difference. There is no noise even with the volume turned up far too loud (still with plenty of headroom). The knobs are smooth to operate, and the single main output volume slider is a joy to use. There are two outputs - 'Main' and 'Control Room' - and I'm using the latter, which has it's own independent set of controls on top of the main ones, with the Sony monitors. The built-in effects are very good so far as I have tried them, but a long way to go there. Very pleased with it - my £89 seems to have provided something well in excess of my wishes or abilities ...

The clip light is showing you "graphically" that your desired signal is in the top story.

First - I don't think the nominal output of Montage is 0dB - I think it's higher (when offset is set to 0dB). But I wasn't going to dig for that. Not necessarily important.

Second - there are other variables too. Although the synth may have a general level for its output - you're playing it - which changes the dynamics according to your playing. ... And this is probably different from my playing. ... And your volume fader may be always set at a different level than I keep mine at. So instead of using something absolute like a single value - use a measurement.

I mean, you do not fly an airplane by mapping out exactly every angle of the controls and throttle amount etc before taking a flight and fly by the numbers. In practice, you use the instruments (altitude reading, heading, speed, etc) as feedback to tell you if what you intend is happening and allows for making corrections. Similarly, in practice you would use the meters or clip light to guide setting the gain.

There is a relationship to the output. However, nominal and actual are different - and this is where adjustments to the reality of your signal chain including the performer have to come in.

My point in relating gain to the output level was to push back on your assertion that mixers had no adjustment to meet different nominal output levels. NOT to encourage using "calculated" number to set your mixer gain knob value.

I'm still not understanding gain but here's another few questions in an example.

1) FACT: The Montage output offers a selectable range as follows: -6dB, 0dB, +6dB, and +12dB. Say I set this to 0dB on the touch screen of the Montage.

2) Whether I turn the volume up or down this value (0dB) does not change (or does it?) from the mixer's point of view? My monitor level goes up and down with the volume change but the set dB on the Montage is fixed at 0dB.

3) My mixer gain dial is rotated up to equal 0dB and I won't ever need to change it because I set it to match the Montage 0dB output value. Is this correct or not.

4) My mind is trying to tell me that this is the optimum relationship between mixer and synth to keep the noise level in the basement.

5) IF in #3, I were to increase the mixer gain up to +10dB and leave the Montage at 0dB, then I have a signal level to amplifier mismatch that moves any noise up to the top floor and thus gets magnified as the volume is increased.

6) In the above scenario I'm matching physical gain numbers which might be totally incorrect. The other circumstance is to forget those numbers completely and use the following method which begs to question: If the method below is correct then why the heck do we need the Montage to be selectable from -6, 0, +6, +12dB because it apparently doesn't matter if all you are going to do is twist a gain knob until the meter light goes up to where you want it to be.

"On the mixer board, you’ll see the gain at the top of the board. It’s the first control that the raw mic signal sees, and it will boost the signal to a sufficient level for the rest of the controls to work properly. You’ll want to set this gain level high enough to bring up the level of the signal, but not so high that you’ll get clipping or distortion in the signal. For this purpose, many boards come with a PFL (Pre-Fader Listen) button. This button will let you see the actual signal strength by looking at the LEDs on the board. Use the mic at normal sound levels and set the gain knob so that the peaks in sound don’t send the signal into the red, and you’re good to go."

Another consideration might be going straight to a monitor (without a gain matching function) so that the Montage has to be adjusted on the signal end.

Hi David,

it is a complex topic, actually. It is from my point of view so complex because the "db" value has different meanings in different contexts.

First of all a "db" value is just a fancy way to write ratios between two numbers: They are written as a logarithmic value. The following table can be used to find the ratio for some given "db" values:

-10 db = 0.1
-6 db = 0.25
-3 db = 0.5
0 db = 1
3 db = 2
6 db = 4
12 db = 16
50 db = 100000

A ratio between two values can be written as r = V1 / V2. If V1 has 4 times the value than V2, then r is 4 (or 6 db). But that means that if V1 is said to be at value 6 db, this says nothing unless you know what V2 is... If V2 is 3 and r is 6 db, then V1 is 12.

In audio the "db" value is used for two things: First, to note what maximum voltage certain equipment can handle until it will clip/distort. The home equipment is said to handle -10 dbV. But since you do not know the reference voltage (V2), that does not tell you anything. The "V" in "dbV" defines that reference voltage. In this case it can handle at most 0.31 V. Studio equipment can handle 4 dbu, but unfortunately the reference voltage is different. In this case this means 1.228 V (to my knowledge). Those values have been chosen for purely historic reasons...

Second "db" is used for the gain of an amplification stage in a signal chain. If an amplifier will amplify the signal to 4 times its input value, it has a gain of 4 which you can also write as 6 db. A gain of 0 db (=1) means the level of the output is the same as the level of the input. Every value above 0 db will yield a stronger output signal, every value below 0 will yield a weaker output signal. The input gain of my mixer goes from -20 db to 30 db. The setting of -20 db will multiply the signal with 0.01, the 30 db setting will multiply the signal with 1000. So the ratio between the weakest and strongest gain is 100000! Which happens to be 50 db.

You need to understand that the volume slider, the Montage's gain, and the mixer's gain are pretty much the same thing when we are talking about "db" values. Each such stage multiplies the input signal with its gain to get the output signal. To get the overall gain, all the gains in the signal chain are simply multiplied together. Overall gain = Gain of Volume Slider * Gain of db setting in the Montage * gain of mixer * ...

That means, if you set the volume slider to multiply its input signal by 0.5 (wherever that is on the slider scale), then set the Montage to 3 db (if you could), the output of both combined would be the same as the input. If you set the Montage to -6 db (which is 1/4), and the slider is at its top, then the overall gain is 1/4. I am assuming that the slider at its top has a gain of 0 db, which means it lets the input signal pass unchanged. I might be wrong there.

david wrote:

I'm still not understanding gain but here's another few questions in an example.

1) FACT: The Montage output offers a selectable range as follows: -6dB, 0dB, +6dB, and +12dB. Say I set this to 0dB on the touch screen of the Montage.

The value 0db means the gain setting is 1, so there is no change in the output power through this setting.

2) Whether I turn the volume up or down this value (0dB) does not change (or does it?) from the mixer's point of view? My monitor level goes up and down with the volume change but the set dB on the Montage is fixed at 0dB.

No, the volume slider is just another multiplier in the equation. If you set the volume slider to half, then the resulting signal is half the original's strength. You can say it is -3 db of the input (see the table above).

3) My mixer gain dial is rotated up to equal 0dB and I won't ever need to change it because I set it to match the Montage 0dB output value. Is this correct or not.

Not really. The Montage has a certain output level which depends on the sound, the part volume, the element volume, how hard you hit, the envelope, on your volume slider etc. How much your mixer can handle, depends on your mixer. If the Montage's output is more than your mixer's input can handle, then you have to lower the signal level in the Montage. You can do that by changing the volume slider, changing the "db" setting in the Montage, etc. If the mixer expects more, then you can increase the Montage's output using one of the means mentioned above. You can also change the gain in your mixer. If you set the "db" setting in the Montage to 6 db and the mixer to 0 db this will yield the same level as if you set the Montage to 0 db and the mixer to 6 db. But if the mixer's input can handle the higher output of the Montage, then setting the Montage to 6 db will yield less noise, than setting the mixer to 6 db. Generally the more gain you can get earlier without causing distortion, the better. Amplifying later will introduce more noise.

So why does the Montage have a way to set the "db" level? The reason is simply that it will give you a much higher range. This setting allows you to go from -6 db to 12 db. This is a difference of 18 db. Which means a factor of 64. So if you leave the volume slider untouched but change that setting from the lowest to the highest, you will get a 64 times higher output signal. That allows you to adapt your Montage to vastly different equipment. Without that you would in some case have to have your volume slider very close to its lowest level and in some other case all the way to the top. I try to keep the Montage in the middle, most of the time. That gives me some leeway for adapting the volume of my Montage during a gig.

One last thing: I found that having the right input level is not only interesting for keeping noise down or avoiding distortion. But in reality those amplifiers are not as linear as one might think. If the input level coming into my keyboard amp is too low, and I have to crank up its gain, I found that it sounds "flat" or even has some not so nice tone. So I most of the time set the Montage to 6 db. Then I don't have to set the gain or output level of the amp so high, and it actually sounds much better. So in my experience getting the right level (by experimentation) is important. And usually that's simply done by increasing the output of the Montage until you get some indication of clipping (like the LED) and then lowering the output again. Like others have described before... But knowing the expected input level of your equipment can help you to start in the right range...

Hello Stefan - Mein Gott! The whole thing is terrifying ... all I did was buy a mixer ...

Rod wrote:

Hello Stefan - Mein Gott! The whole thing is terrifying ... all I did was buy a mixer ...

Well you asked too many questions 😉

I suggest you just stop thinking about it. If it is a good mixer, set the Montage to 6 db. Adjust the gain in the mixer so that you get no clipping whatever you play. Then everything will sound great...

Hello Stefan - you got it, man ... :o)

I learned what I could grasp. It's actually humorous and now I see why audio engineers have jobs. Literally we've come full circle back to turning the knobs and listening to what we hear. dB shmebe! Bah Humbug! etc. 😀

Full circle would imply that we ever suggested something other than using the peak light/meter to set the gain - at least for that one thread of discussion. The practical suggestions have always been the same. Discussions around the more technical topics were to correct some errors in translating the information, provide analogies to relate the technical information to other things, etc.

Sound engineers are in business not necessarily because they can use correct terminology to explain the "mechanics" of what they work with - but because they do a good job at the task at hand when others are not as adept.

However, the terminology is important (to have in general) because it sets a standard - like anything else (motorheads you'll hear discussing displacement, etc - other industries have their own sets of common terms). There is a meaning to all this "gibberish" although if you need to learn the meaning depends on your interest level and the absolute need to do so (which could validly be low on both counts).

The extent of my mixer explanation for the purpose of the gain dial states in one sentence "This adjusts the gain of the input amplifier TO MATCH the signal level of the input." Therefore if my signal level from Montage is +6dB then this dial should be set to +6dB. "TO MATCH" means equal values. If the Montage volume slider changes the +6dB level then set the Montage level to a fixed position and determine the new cumulative dB level and then set the mixer's gain TO MATCH that value. Your mixer should have a dB scale usually somewhere from -30dB up to +15 or similar range next to the level meter. Use that to experiment with the effects of making real time adjustments in your slider and gain levels.

Hello david - My mixer has 4 mic input channels with both XLR and balanced jack inputs, full 3 band EQ and a rotary gain control on each, as well as the channel volume etc: - all of which takes up half the available space and is totally wasted on me - I have no use whatsoever for mic inputs. There is no EQ on any of the 4 stereo channel inputs, and the gain control is limited to a push button (+4 and -10) - it's the penalty for buying a cheapie! But I find it's adequate for my modest needs, and I'm pleased with it, which is all that actually matters! Things that matter in a professional studio are largely irrelevant in a home set-up - just play the notes, man ...