Ideas on the blend knob

I love delay… I use the setting of 1/4 and dotted 1/8 notes to give an amazing feeling of space around my playing. Add a hall or chamber reverb and I’m in heaven…
The recently added Bollie Delay with the tap tempo function on the incoming release just took my MOD to new heights. Loving the DUO even more each day…

However, I want to discuss the blend knob as I think that many developers don’t put much thought into it… To be blunt I am not a fan of it, especially for delays. When I play, I want my direct signal going through and be able to adjust the delay level. The problem with the blend knob is that at a certain point the direct signal is attenuated. Luckily the DUO’s easy routing makes it very easy to accomplish my goal by sending a direct signal to the output and having a parallel line to a gain plug (for setting send level) and then to the delay set to 100% wet. There are some delay plugins with dry and wet level signals and this works when in-line.

A blend knob is the easiest way for a user to just get to a sound that works best. However, it’s a real bummer when you want to switch on/off the delay and find that your direct signal keeps changing levels. It all depends on how you want it to work for you but the blend knob can be a kind of mystery since we don’t know where the direct signal gets attenuated.

There are different blend algorithms where the dry and wet signals are mixed in different ways. For example a simple blend could be a linear rise of wet and linear decline of dry which is a problem because as soon as you start moving the knob you lose direct signal. Another example is to have the direct signal flat to the middle (going dry to wet) and wet signal come up to equal, then dry drops off as wet stays flat, like a DJ cross-fade slider… but what if you want to keep direct signal and get louder delays (probably won’t happen too often but it’s an idea…).
The desired effect would be different for different kinds of plugins. Delay/reverbs I like direct signal always going through at the level it goes in. On compression (parallel compression is amazing), it can probably be a linear up/down.

My point is… that I want developers to put some thought into how they do the blend knob in whatever plugin they develop. It can be a wonderful part of the plugin but it can put a damper on the use of it and require the user to take extra steps to use it in their setup if not done right.

My two cents…


The rakarrack plugins use exactly this sort of wet/dry blend which I always thought was really weird. Never realized how it could be useful for verb or delays.
Very interesting feedback. Thanks.

Most of my own design plugins I would have a master level control as well as a mix control so between the two you can achieve whatever level changes you want between bypass and active. You would rather just have a wet level and dry level knob?


There are many ways to come up with the same result. Your blend then master control should work but it’s a little more to think about.

I think most guitar effects like distortion (overdrive/fuzz) would be 100% effected. But, for bass having a direct signal added to the distorted signal can keep deep tone and nice distortion. Clean electric guitar tones can work well with some direct sound and an amp sound blended. I really like the easy routing offered by the DUO and I experiment with a lot of blending… but it can be quite a mess of “cables” on my pedalboard…

I guess my preference is to have a separate level for dry and wet. This would cover all bases and would be the same number of knobs as having a blend and output level.

1 Like

Hey there,

thanks for your feedback. Despite being the complete newbie on making plugins and this delay being my first try, I actually had a thought behind the blend knob: I wanted to avoid too high output levels, so instead of adding wet to dry, I changed proportions on this.

However, I see your point and yes, it’s a good idea to improve that. Someone just showed me a so-called V-fade approach of Robin’s XFade. That looks appealing and sounds like what you mentioned about the DJ crossfade.

How about I’ll add that in a new release?



I guess I just want to let developers know that there is something to think about here.

I really like the approach that TC-Electronic takes with their delays. They let the direct signal go through.
Maybe in the plugin there can be a switch for the option to let direct signal go through and the blend knob becomes a wet level. This would reduce the amount of cables I use on the pedalboard… :slight_smile:

this discussion could actually be taken a bit further.

we have a host side implementation for the output volume of the plugins, so that the developers don’t need to worry about it.

would a host-side blend or mix control also make sense?


I like the idea because it would mean that each plugin gain structure would be more standardized.

However, what kind of mix control would it be?

I like where this is going…

Sure, that might lead to more consistent plugins, but on the other hand, a plugin-internal mix might be needed for other lv2-hosts anyway. So I stick with Skydiver’s encouragement to really put more than one thought into the design of dry/wet controls.

I’d really love to hear more opinions on that. @x42 ?

1 Like

Indeed, the MOD is replacing my tc d-two and so that was also my motivation to make a delay plugin that has certain features I love. :wink:

1 Like

I think there are challenges in a host-level mix. Especially with plugins with latency. Most plugins that could use a mix knob have one anyway I think. And as mentioned above, on reverb and delay it makes sense to not affect the clean level at all, only adjust the wet. On other effects like a chorus, this makes no sense at all! So I think its effect dependent, and should be thought about by the developer.

This kind of user feedback is very valuable.

EDIT: I should also mention that the reverb needs of a guitarist on stage is very very different than an electronic producer in the studio, and that would change how the blend works too.

1 Like


Good default values, proper control-port ranges. a good balance of which controls are directly exposed and which are implicit are the hallmarks of professional plugins.

This an area where that leaves a lot to be desired for some free software plugins. There is some excellent DSP out there that eventually is not very usable in the real world due to seemingly small details like the ones mentioned.


1 Like

Host side blend does not make sense to me. There are very few cases where it’ll be useful and work properly and a lot of cases where it’ll effectively just be a comb-filter.

1 Like

Very true. I come from a studio point of view so I think of delay and reverb on an Aux channel and I am able to design my pedalboard the way I want with the DUO. (Love this thing…)

On a traditional pedalboard (not virtual) it’s a single signal path so the blend knob is typically what is used. TC-Electronic (and others) have implemented the studio way into their pedal.

At the end of the day it’s whatever works for you…
I’ve seen some very interesting things in studios and pedalboards but they sound great!

I was wondering about the phase relationship.

I have some effects which run in parallel to a direct signal and wondering if I’m getting some phase issues.
Should I be worried about it? If it is happening, how can I fix it with what we currently have in plugins?

(Sorry… This is getting off topic…)

No. only worry if the result sounds strange to your ears :slight_smile:

I don’t think you can. There’s no sample-based delay on the MOD, and you’d also have to find the plugin(s) that may have short latencies and don’t announce them – some EQs or filters for example could add 1 or 2 samples delay.

But latency compensation is actually something that should be built into the host. Delay the dry path accordingly to line things up at the output.

Does the DUO have this?
I would think this would be difficult considering how the cables can run, nothing like a mixing console where delays at each channel can be measured and then corrected.

I don’t know but I don’t think so.

It’s far from trivial, but the mechanism is already in place because it’s needed for the execution graph itself (in which order the FX are called) which depends on the connections. JACK (the sound-server on the MOD) also provide information about port latencies in both directions (upstream/capture and downstream/playback latency). JACK itself does not delay but only provides the information. the plugin-host can use that information.

1 Like

Hey @Skydiver!

Thanks to you motivating me on investing a few more thoughts into the blend knob, I changed it’s behavior. From 0-50, you know blend wet to the untouched dry signal, while above 50, wet is at 100%, while dry is being faded. I also added some low pass on the input parameter to make sure, turning that knob results in a smooth blending.

The updated version should be available in the plugin store.



I will give it a try. It may simplify my signal flow so that I don’t have to place it in parallel and use another gain plugin.

I will report back.