Reverb 101 Basics

[sureno]

Reverb 101 Basics

So as i said i would continue my articles which now brings me onto Reverberation, this will be like all my others, hopefully simple and ideal for beginners. Reverberation, Reverb and even Verb are used to describe the natural reflections that occur in natural environments. A great example how ever cliche it may be would be a person shouting "Hello" into a cave and here's the echoes from the word shouted "hello-o-o-o" yes its a crude example but you surely know what i mean. Why does this happen you ask, well let the newly appointed "Forum Idol" tell you when a sound is produced (e.g your voice) the resulting changes in air pressure emanate out in all directions but only a proportion of this reaches our ears directly. what happens to the rest? well they rebound of nearby or in some cases not so near surfaces such as walls, ceilings etc taking that much bit longest to reach our ears. in most cases the distance of surface is proportionate to time it takes for the sound to reach our ears. Ok so these reflections will create a series of discrete echoes that all closely compacted together giving the listener info about the surroundings, small, medium, large etc. These reflections are absorbed by the surface they reflect on each time absorbing some of the sounds energy and in hand reducing its amplitude. Ok so that i don't get a grilling from some of the higher ranked members i will mention that different surfaces have different and individual frequency responses, basically different materials will absorb different frequencies from the sounds energy but i will not be getting into the subject as this is a 101.

Size of area:
Well say you where in a large warehouse with a freezer large enough to store fairly sized mammals and no signs of life for miles and....... oh yeah thats another topic but say your in a large ware house and shouted "HELP", it would take longer for the reverberations to decay away than it would if you where in a smaller area say the freezer for instance, though if i had locked you in the freezer, i mean if you happened to stroll into the freezer i suppose you would have other things to worry about than listen to the difference in decay on reverberations caused:-) Now concentrate here, the further away from a sound you are, the more the reverberations would be until eventually (depending on correct conditions and distance of sound) you would just hear a series of distinct echoes rather than an immediate reverb effect (you must of seen films where people shout into the grand canyon).

I will say however every one has experienced Reverb! It is such a natural occurrence in every day life that if it where to be removed it can cause an unsettling feeling in certain individuals. The blindfold test, if you where to be Blindfolded (warehouse scenario all over again, mwah ha ha ha ha:-)) you would almost certainly be able to tell what type of room you are in and roughly imagine how big all because your brain interpreting times and frequencies of the area around you as every material has it characteristic frequency resonance and size has it's certain echo if you will.

! There is SO much more to Reverberation ! but i don't think any more info from me would be immediately beneficial and you can also look it up yourself. also i must add that reverberation to a physicist and what it is to a musician varies. Technically a reverberation is not the same as an echo.

So what's this got to do with me???
Fair point, in my opinion the compressor is one of the most if not the most important processor in my mix, the Reverb one of if again not most important effect in my mix. why is it important? because samplers, sounds and synths etc do not generate "natural" reverb until there signal is actually exposed to air so in order to give your mix, group what ever you wish that you feel needs it a depth to it we have to use a "Reverb" unit, please don't ask why is it called a "Reverb" unit.lol which will artificially add it:-) i like my other threads am not here to tell you when or where to use it mind but just what it is and how to manipulate it.

The Reverb Unit/Plug:

Now when you have the unit in front of you, you will usually have the following controls

Ratio/Mix or Dry/Wet:

Dry= unaffected original signal
Wet=The actual reverb caused by the signal

this is presented in lots of different ways but all give the same effect, they can be individual controls for wet(volume of actual reverb) and Dry(volume of actual signal) or in 1 control offering a ratio of Dry/wet mix, here the more you turn the control to the desired effect the more that effect will be heard in comparison the the effect you are moving away from.


Pre-Delay time:

this control changes the time taken for the start of the unaffected signal to the start of the first reflection, good for when sounds have a long attack so you can give the sound time to develop before the reverb kicks in so as to not overlap the 2 and cause a muddy mix.

Early Reflections:

Ok this controls how the first few reflections are heard, because it usually isn't just one surface reflections occur on we receive slightly different sounding ones from each surface, an early reflection control will allow for this altering each early reflection in accordance.

Diffusion:

This is related to the early reflections control, diffusion will measure how far the early reflections are spread across the stereo image. The amount of stereo image depends on how far away the sound source is.
Further away: much of the stereo image will dissipate
Up front: more reverberation but the stereo image will be closer almost seeming monophonic

Density:

After the early reflections comes the remainder, this is referred to as the density. So on the unit this will control the number and speed at which the reflections occur.

Reverb Decay Time:

This i hope by now is pretty obvious, as i have covered decay in my last two 101's and glossary but for those of you that missed them the reverb decay time is the time it takes for the reverb to decay away or simply fade out. In larger spaces this will usually take longer than in more confined areas. i do how ever use this control with caution as it can really muddy certain sounds in a wash of different frequencies from previous notes if there is too much decay.

SURENO FUN FACT: The amount of time it takes for a reverb to fade away after the original sound has stopped is measured by how long it takes the sound pressure level to decay to 1/millionth of its original value.
1/millionth = a 60dB reduction so reverb decay time is often referred to as RT60 time.

HF & LF Damping:

As the abbreviations suggest this will adjust the amount of High Frequency & Low Frequency respectively.
we have these controls because the further reflections have to travel the less high frequency content they might have as the medium they will be traveling through (air) will absorb them and so will soft furnishings. so by reducing HF and the decay time we can give the listener the impression that the sound is in a small area or in my padded cell:-) Now by increasing the decay time and removing select amounts of HF you give the sound source the image of being further away. Now at the other end of the chart by increasing the LF damping you will make the sound source appear as if in a large open space.

Every reverb will have it's own version of these controls under different names or even the same so always get used to the manual or guide accompanied with it.

Convolution Reverb

This is where the reverb will digitally simulate the reverberation of a space, using the convolution method. It uses pre recorded audio samples called Impulse Responses or IR's for short. These samples are recordings of the impulse response from the spaces being imitated by the reverb. I wont go into this process in any great detail as i really couldn't do it justice but these are the more favored plugins in todays studio but at a cost they demand higher cpu. but to give you a very vague idea to the process behind it, you will often load an IR into your reverb plug where it is then convolved with the incoming signal to be processed!

Any way if i didn't help watch the super simple video on reasons reverb



Reverbs I like:

Logic Studio's

Platinum verb not convolution
or Space designer convolution


Audio Ease Altiverb 6 convolution


Overloud Audio Tools Breverb 1.5 not convolution

[sphelan]

+1 yet again Paul.

[maximlee]

yeah signed up thinking id have a chance at winning vst....after reading this and ure other articles why bother..... back to writing tunes i guess which....

[sureno]

Originally Posted by maximlee

yeah signed up thinking id have a chance at winning vst....after reading this and ure other articles why bother..... back to writing tunes i guess which....

Add to it, you will learn so much here, not saying you need to learn more but its always handy

[sphelan]

Originally Posted by maximlee

yeah signed up thinking id have a chance at winning vst....after reading this and ure other articles why bother..... back to writing tunes i guess which....

May be that's not a bad idea there maximlee. There are a few of us who could follow that advice.

[e-vinyl]

ok sorry for my post i misread the article
Anyways great job sureno

[sureno]

Originally Posted by e-vinyl

ok sorry for my post i misread the article
Anyways great job sureno

What post e-vinyl?

[e-vinyl]

i posted a chart of reflections on an average empty room

[sureno]

Didn't see it? where is it?

[e-vinyl]

I quickly took it off because i felt it wasn't related to the article.
But ill add a new one that i think it is

[sureno]

Originally Posted by e-vinyl

I quickly took it off because i felt it wasn't related to the article.
But ill add a new one that i think it is

it is related, i wrote a little about early reflection and what it is and density. it's a shame i can't include it as my pic limit has been maxxed out but keep the pic its all good

[e-vinyl]

Originally Posted by sureno

it is related, i wrote a little about early reflection and what it is and density. it's a shame i can't include it as my pic limit has been maxxed out

That one i know it is but the other one wasn't that's why i took it off

[sureno]

Originally Posted by e-vinyl

That one i know it is but the other one wasn't that's why i took it off

lol, ok then well nice pic Mr e-vinyl

[e-vinyl]

thank you, i thought of making up for this little confusion

[sureno]

Originally Posted by e-vinyl

thank you, i thought of making up for this little confusion

hey if ndk lifts the pic number can i include your pic giving you credit for it?