Types of Reverb

It’s time to talk about reverbs in detail. We briefly mentioned these wonderful tools when we analysed the mixing template. Reverbs can do a lot for your mixes, and if you produce orchestral music they really are super important. There are two main types of reverb and they usually serve different purposes although we can mix them up and ultimately we can be very creative when using them. It’s also worth mentioning that whilst some plug ins out there (or hardware) can be very expensive, you can achieve great results with inexpensive or free reverbs, so if you are budgeting for a good reverb and are unsure which one you should get you can definitely get a lot done with your DAW’s built in ones in the meantime, or check some of the free ones. Let’s find out what the main types of reverb are…

The two ways

All reverbs recreate space, you have the opportunity to run a signal through a piece of software or hardware and place it virtually into a room, hall etc…how the space is emulated defines the type of reverb: algorithmic reverbs use mathematical ways to reproduce the sound of a room, whereas convolution reverbs use “blueprints” of real spaces, known as Impulse Responses, each method comes with advantages and disadvantages but most importantly these two techniques are both really valuable and the two types of reverb can be very useful for different situations.

Convolution reverbs

If you compose or mix orchestral music, these are your bread and butter. Convolution reverbs are great for recreating a natural sense of space. Even if you work with samples that are already wet a good converb always has its uses. They are great for other genres as well: whenever you need to emulate a natural sounding room, Impulse Responses are the way to go.

These reverbs usually take quite some CPU and they don’t always lend themeselves to a lot of tweaking: it is possible to change the lenght of the tail and make other adjustments (depending on the plug in) but you will find that if you need a shorter sounding reverb it’s easier to just pick a shorter IR.

Some mixing engineers find the tail of convolution reverb “uninteresting”, we will explore potential solutions to this problem later in this article.

Algorithmic reverbs

Whatever type of music you make, these are your friends, a good algorithmic reverb is always useful. These plug ins are generally easier on the CPU (not all of them) and they are great for making interesting effects, they lend themselves to a lot of tweaking and allow you to create artificial “unreal” spaces too, should you want to. They can be used to add flavour to sounds that are already wet.

Algorithmic reverbs might sound less three-dimensional and give you the idea of a spatial effect that is “added” to the sound rather than something that “embeds” the sound. Good algorithmic reverbs are know for their interesting tail, at the same time some of the less expensive algoverbs might have a “digital aftertaste”, kind of a fizz as the tail fades out.

How to use them

If you are mixing acoustic instruments (starting from a single instrument to a whole orchestra) choosing the right convolution reverb is a good starting point. You won’t need too many instances: you can either have one FX channel with the converb on it and adjust the send level for each individual channel or you can insert a convolution reverb on each bus group. For instance if you are mixing an orchestra where you have strings, woodwinds, brass and percussion routed through their respective bus groups you can place one instance of the same convolution reverb on each section bus and then tweak the dry/wet ratio based on how far each group must sound. Both methods are valid, they both have pros and cons, try them and see what works for you….

Whenever eq’ing a convolution reverb, you want to find the annoying resonances (often but not always/only) in the lower mids and lows but you don’t want to roll off the low end because that’s an important part of how a real space should sound, be careful and get rid of the nasty resonances without denaturing the ambience otherwise your mix will simply lack depth.

You can apply this approach to an algoverb and use it for an acoustic or orchestral mix, however most mixing engineers would probably pick a converb in this context, especially if they are working with dry samples.

On the other hand, if you are mixing pop, rock and many other genres you might want to try algorithmic reverbs first for things such as vocals, lead guitars, synths, individual drums such as the snare etc…. algoverbs are great for their flexibility, you can shape them in so many ways and do what you want with the tail. It is advisable to keep a few options at hand, so for example you can create two FX channels, one with a shorter reverb and one with a longer reverb, then send the individual tracks to one of those depending on what works best.

If you like, you can carve the low end from an algorithmic reverb and free up space in the mix, unless of course you are using it as your main orchestral reverb, in which case you might want to apply a more conservative eq for the above mentioned reasons.

When to use both

It is certainly possible to use two reverbs, in fact in some cases it’s actually advisable. If you process a dry sound, such as a solo instrument in the context of an orchestral mix, and you found the right balance with your convolution reverb but the instrument still lacks something, it still feels somehow dry or it simply requires extra smoothness you can set another send and dial in a nice algorithmic reverb as well! This will generally have a lower send level compared to the “main” converb but as always there are no rules: every mix is different.

You may use the same technique for an orchestral section that just requires extra lushness, but also for snare drums and toms (as we mentioned before), even though you have room mics for real ambience these drums often need extra help to sit nicely in the mix.

Hybrid reverbs

Earlier on I mentioned how some mixing engineers find the tail of convolution reverbs “uninteresting”…now hybrid reverbs, albeit less popular, offer a solution to this problem because they combine the early reflections of a convolution reverb with the tail of an algorithmic reverb.

With that in mind you can easily make your own DIY hybrid reverb:

Simply create a bus group for each section of the orchestra (will work with any group of instruments of course) and route the instruments to their respective section, on each bus group INSERT a convolution reverb and just mute the tail, in other words just use it for early reflections…

Then create an FX channel with the algorithmic reverb and just select the tail from that, finally on each bus group create a send to the algoverb and you will be able to handle the two components of the reverb (the early reflections from the converb, and the algorithmic tail) separately.

This process might sound needlessly complicated, but it’s just an interesting experiment and it will give you more options for mixing without having to buy new plug ins. With that being said you should be able to execute most mixes without having to resort to this technique.

Dereverb

It’s worth mentioning dereverbs, because sometimes tracks are too wet and you don’t have access to single mics, close mics etc… dereverbs and transient designers can be very helpful in these cases.

Vienna Suite

This blog is not the place for paid promotion, if you see any product names here from time to time it’s just because I use these plug ins and find them really valuable.

Vienna suite is one of these products, the normal (non pro) version is really affordable and features some incredibly transparent mixing tools (eq, comp, limiter etc…). Most importantly it comes with both a convolution reverb and a hybrid reverb so if you are starting out mixing music, especially orchestral music, you must check out this bundle: it’s also incredibly easy on the CPU. The Impulse Responses alone are worth the retail price. Obviously there are better, more expensive options out there (such as Altiverb), so always do your research and never buy anything just because it’s mentioned on this website.

Do you have any questions or want to let me know what your favourite reverbs are? Send me a message.

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