Delay / reverb developers - Add separate dry/wet knobs to your plugin!

[Lesha]

There's one thing that annoys me, and that is a lot of delays and reverbs have a single dry/wet knob. That makes me not want to use them at all because I must compensate for the drop in dry level and that makes me

Why is it so hard to make separate dry/wet knobs? Did anyone think about using a plugin on an insert?

I wish all delay/reverb developers would learn from NastyDLA!

[mutantdog]

I posted a poll on this subject a while back and the majority of people who voted favoured a single wet/dry mix control over separate levels.

Personally in the case of reverbs and delays i kinda prefer to control wet and dry levels individually, on the other hand a chorus or distortion tends to work better with a single mix control. That said, there are plugs that use some sort of non-linear mix which i find work quite well (TkDelay springs to mind here).

[aciddose]

If you don't use a "mix" control, your levels will be all over the place.

Why do you need to maintain the dry level? For what purpose?

Using the "mix", the total level will be maintained regardless of the mix position. That is its purpose.

For example if you run reverb -> envelope follower filter and adjust the reverb mix. The cutoff won't change on the envelope follower because the total level will be maintained.

If you have a problem with maintaining steady levels (you don't want to maintain a steady level regardless of mix) you're doing it wrong. The solution is to combine a mix with a gain which should be included in your host if you use a send. If you use the reverb as an insert you'll need to compensate between plugins if needed but I can see no possible reason for using unity dry, ever.

Short answer: No.

Extended: One thing that can throw off the "total level" is when the level of the individual parts being mixed is not equal. For example this can occur when you use different amounts of feedback or filters on your reverb/delay. If you use a low-cut for example you often need to bring the level up a little bit to maintain RMS == between dry/wet.

Every reverb/delay should include a "gain" for the wet level compensation and a simple RMS level meter, if anything. That would be super useful.

[mutantdog]

As an example, say I've mixed the level of my snare to that which i want and then decide i want to add some reverb or delay to it. For some reason I've decided that i want the effect to be inserted rather than put on a return (pre-distortion perhaps).

Using a wet/dry mix on this means that the dry level which i have already determined to be right will now be reduced to make room for the effected level. This is not necessarily what i want, adding a reverb tail to a snare shouldn't affect the transient volume of the main sound.

This might not be the case for other uses, mix knobs would probably be better on pads for example. On sends, its largely irrelevant.

[aciddose]

The result of the distortion then you want to increase as you increase the wet level.

Why don't you just set the mix where desired and then increase the drive? Identical although far more intuitive result.

Why should the mix have an effect on the drive? That doesn't make any sense. These should be two independent controls.

The argument is the same as to argue we should be using two controls for left/right level rather than a panning control. The purpose of the panning control is to perform a complex calculation for us automatically based upon a panning law that we would otherwise have a very difficult time managing on our own.

Far more likely you'll be wanting to pan a signal left or right by a fixed amount while maintaining the total level of that signal. Very rarely if at all will you want to individually control the gain of the left and right channels.

[aciddose]

More detail on this:

mix = signal_a * sqrt(level) + signal_b * sqrt(1 - level)

This is called an "equal power" law. This only applies to uncorrelated signals such as two independent sources of white noise.

Mix will always = 1 regardless of level. This is because for uncorrelated signals, the equal combination of the two signals results in a gain of +3db. sqrt(1/2) equals -3db, so the result is a continuous 0db.

For correlated signals the result of an equal combination of the two signals is +6db. Correlated signals are for example if we use the same signal.

mix = signal * (level) + signal * (1-level)

Again, mix will always be exactly 0db, we can actually use algebra to remove level entirely and end up with:

mix = signal

x*y + x*(1-y) = x

See "alternate forms":

http://www.wolframalpha.com/input/?i=x* ... *%281-y%29

Mix/pan are the same thing.

[Lesha]

I just want to have a choice. With a single dry/wet knob, that choice is non-existent.

[aciddose]

You have the choice to do the additional work to compute the mix + gain you need to use to get the result you want, or alternatively use mix = 100% and manually handle dry and wet levels directly.

Either you force most people who are using these tools most of the time to do a lot of extra work to turn wet + dry into mix, or you are forced to take mix and turn it into wet + dry when you rarely need to.

You're really better off to learn how to work with the tools in a way that you do not need to do this at all. I think you should find a lot of trouble to realistically justify that you need individual levels when you apply it in practice.

You should realize you want to stomp the gas and break pedal at the same time. This doesn't have any practical purpose.

[mutantdog]

The result of the distortion then you want to increase as you increase the wet level.

Why don't you just set the mix where desired and then increase the drive? Identical although far more intuitive result.

Why should the mix have an effect on the drive? That doesn't make any sense. These should be two independent controls.

The distortion example was fairly arbitrary, it just happens that i tend to like running some saturation on the end of my snare channel. Whether that's good or bad is a matter of personal preference and largely irrelevant. The point being that for whatever reason in this semi-hypothetical case the reverb is to be used as an insert rather than as a send.

Now in this scenario at different parts of the track a reverb tail is desired while at other parts it is not. In any case the volume of the initial hit of the snare must remain constant. In such a case if increasing the wet also decreases the dry then a separate gain adjustment is also required in order to maintain the same level for the dry signal. This isn't a massive issue but it can be annoying.

The argument is the same as to argue we should be using two controls for left/right level rather than a panning control. The purpose of the panning control is to perform a complex calculation for us automatically based upon a panning law that we would otherwise have a very difficult time managing on our own.

Far more likely you'll be wanting to pan a signal left or right by a fixed amount while maintaining the total level of that signal. Very rarely if at all will you want to individually control the gain of the left and right channels.

It's completely different. The wet signal is an addition to the dry signal, in no way can the right be considered an addition to the left. A more suitable comparison might be that wet is analogous to the side while dry is analogous to the mid. I also prefer my M/S plugins to have separate controls for each, as opposed to the more restrictive less-more stereo knob.

The equal-power law is not the be-all-and-end-all of audio mixing and isn't necessarily appropriate to every case. This is why you see ducking delays for example.

[aciddose]

It isn't different, you're just looking at it with tunnel vision.

The total gain of the wet+dry mix will not be reduced, it will be equal to unity.

Perhaps you have your reverb set up with a delay... this is simply a consequence of the way it works. If you however play a sustained signal into the reverb until the reverb has built up to full volume the amplitude at the output will be = unity, regardless of mix.

It is only when you use this very narrow and rarely applied situation that the issue comes up. The initial snare hit probably lasts much less than even the pre-delay of the reverb, so the two signals never overlap. Now the result will be that the individual signals both have had their level reduced in order to ensure that the overlapping mixture of them which never occurs would = unity.

Yes, that is a bitch. Unfortunately you're asking for a lot more trouble in most of the situations you'd be using the plugin to solve this one minor issue (requires you to adjust the gain/drive/makeup) which is rarely encountered.

When you look at this from a broader technical perspective the total gain is still unity, just that you are only hearing individual components and not the mix due to having them isolated in time.

If they are completely isolated you could actually apply a send + saturation to get an identical result.

snare -> saturation + reverb -> saturation when isolated in time is equal to
snare + reverb -> saturation.

This is the proper solution if you are applying the dry + reverb independently as you describe.

Although in most cases that would be stupid of course. You can also just apply between 0db and +3db of gain before or after the reverb.

The total solution to this example case would be a "fix dry = unity" button next to the mix knob. This would automatically adjust the gain to ensure dry always is equal to unity. So the result would be Wet would go from zero, to unity, to infinity at 100% wet. Obviously the mix would need to be limited to something like 75% wet so the total gain would be at most +6db or so, infinity is likely rarely if ever desired.

Otherwise, the individual wet/dry controls you have no way to combine with mix.

[farfadetfarfelu]

i'm totally with lesha here, separate dry/wets or in case of a single parameter, at least a way to adjust the crossfade ratio (constant power, etc).

As a musician wanting to preserve in most cases a constant level for the "dry" signal for my instrument, there are countless situations where i have missed indepedant dry/wet controls. in that situation, the level increase when the effect is turned on and added to the dry sound might actually be desired.

And you look really stupid when you press a button on stage and your really loud dry sound just goes down 50% when you turn on a reverb.
Even if the overall level stays constant, the overall perceived "loudness" difference and the discontinuity in sound will be really be obvious, because a wet reverb sound has totally different characteristics.

Actually i remember Eventide had to change the taper on the mix/dry knob of their Timefactor delay pedal after it first came out (firmware update) because of user complaints about this...

Also, adjusting EQ or tone controls on an effect usually changes it's output level. So in the end you never really now what you are doing with a single crossfade style dry/wet parameter.
imo for that type of use, separate controls really makes it simpler.

[Tricky-Loops]

But what about using the delay or reverb as a send effect, that way you can blend the dry and the wet version perfectly together!

[farfadetfarfelu]

But what about using the delay as a send effect, that way you can blend the dry and the wet version perfectly together!

This will work if you are using one delay or one reverb.
But if you want to chain 7 or 8 effects in series, and have a dry signal at the input of each effect, then it's a lot more complicated to use the aux send method. Well, in reaper you can do parallel chaining in an FX send, and that's why i'm using it.

[mutantdog]

It isn't different, you're just looking at it with tunnel vision.

The total gain of the wet+dry mix will not be reduced, it will be equal to unity.

Perhaps you have your reverb set up with a delay... this is simply a consequence of the way it works. If you however play a sustained signal into the reverb until the reverb has built up to full volume the amplitude at the output will be = unity, regardless of mix.

It is only when you use this very narrow and rarely applied situation that the issue comes up. The initial snare hit probably lasts much less than even the pre-delay of the reverb, so the two signals never overlap. Now the result will be that the individual signals both have had their level reduced in order to ensure that the overlapping mixture of them which never occurs would = unity...

Hey, you said you couldn't think of a reason why anyone would want to keep the dry signal at unity, i've just given you an example of one. I'm sure i could think of more, mostly related to percussion and short transient sounds. Maybe for you that's a rare case, but for me that comprises a large part of the music i make.

Without wanting this to deteriorate into bickering, i would say that it seems you are the one looking at it with tunnel vision since you seem to only be concerned with maintaining unity, and your implication is that anyone who doesn't share your thinking is wrong. This is ultimately a matter of personal preference. Given the choice i would prefer separate controls but its not a deal-breaker, TkDelay is my current go-to but i have several others to choose if i want. There are always other ways to achieve similar results, still there's no harm in expressing a preference for one system over the other, especially when both are commonplace.

Anyway, one more real-world example. Imagine yourself talking at a constant volume in a room, then imagine all the damping being removed from this room and you continuing to talk. The reverb of the room will be added to your voice and the total volume will increase. There is nothing in the physics there that insists on maintaining any arbitrarily chosen amplitude so why should maintaining unity be so important in a reverb plugin?

[aciddose]

I just gave you guys a solution to the problem that would work in all possible cases, not a work-around, not a trade-off.

You need a button by the mix knob that turns it into a "wet level" knob by adjusting the gain automatically to fix the dry at unity.

You aren't looking at this as a designer of these things, you need to actually sit down and work with this stuff and you might find out wet/dry controls suck hard when you have nothing else. There are many valid reasons for a mix control and replacing it with wet/dry does not make sense for the vast majority of cases.

If you were a designer you would also understand it is not possible to combine both controls. You could switch between them, but not combine them.

Why would anyone need to manually control both wet and dry level though? The fact is they wouldn't.

You're obsessing over details while you need to focus on the core of the issue here. If you can come up with a situation where mix + fix doesn't work, that means it isn't a solution.

Otherwise, problem has already been solved.

so why should maintaining unity be so important in a reverb plugin?

You've got to be kidding.

In case you're serious I'll actually explain it. It is simple.

If you don't have unity through the signal chain the result is the level you apply at the fader isn't actually the level you get.

Fader = -10db, I want -10db.

If something in the signal chain has added -4db, that means I'm getting -14db instead of -10db. I want my meters and my faders to agree.

If you want to be all over the place you might as well just use unlabeled knobs and forget about faders or labels or meters.