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joe_04_04 11th July 2015 11:22 AM

AudioThing Fog Convolver
8 Attachment(s)
Plugin: Fog Convolver
Developer: AudioThing
Formats: VST, AU, and AAX (32/64bit) on Windows XP SP2 or later / OSX 10.6.8 or later
Price: 75 USD
DRM: License File
Demo Restrictions: Outputs silence periodically, save and import functions disabled, smaller impulse response library.
Website: AudioThing's Fog Convolver


AudioThing has been popping up in the audio plugin market quite regularly recently. Even though they are a fairly 'new' company in the market, their plugin collection is rapidly growing and expanding quite quickly. Their most recent creation is Fog Convolver, a convolution plugin that not only offers some creative sound design controls for changing and manipulating the impulse responses, but also boasts a very intuitive graphical user interface with excellent visual feedback. Combine this feature set along with fairly low processing usage and an extremely fair price point and you have a high quality plugin.

Sound Quality - 10/10

It is a bit hard to actually review the 'sound' of Fog Convolver, mostly because Fog Convolver doesn't really have a sound itself. As a convolution plugin, it "applies the sonic character of an impulse response to another sound in real time." This means the sound quality you receive will be entirely dependent upon the quality of your source track and the quality of the impulse response. With that being said, I think Fog Convolver comes with a nice library of impulse responses that not only sound good, but also encourage creativity. You are given everything from impulse responses of spaces that replicate large reverberant rooms to impulse responses that impart maybe a 'sonic fingerprint' of a specific piece of gear, such as a telephone or microphone. You are also offered a bunch of abstract sounds that you can use to creatively affect whatever you are running through it.

Features – 8/10

Fog Convolver has a bunch of handy controls that allow you to quickly change and edit the impulse response.

On the left, you have both a stretch and gain parameter. The stretch parameter will allow you to expand or compress the duration of the impulse response so that it occurs either faster or slower. The gain adjusts the volume of the of the impulse response.

On the right, you have separate wet and dry sliders. This is a huge bonus as not all convolution plugins offer this system. In other wet/dry systems, you are given only one knob that slowly fades from wet signal to dry signal. The issue with this system is that if you want to insert this convolution plugin directly into a track's insert, your source track's volume is automatically reduced as soon as you blend in some wet signal. If your track was already mixed, you'll have to adjust this on the mix fader in your DAW. Fog Convolver has separate wet and dry sliders, so you can just blend some wet in without losing any volume in your dry signal.

In the middle, you are offered some creative sound design controls that change or effect the impulse response:
  • Pre-Delay - inserts a delay before the impulse response
  • Start -adjusts the starting point
  • End - adjusts the end point
  • Fade In - adjusts the fade in
  • In Curve - changes the shape of the fade in (sloped or curved)
  • Fade Out - adjusts fade out
  • Out Curve - changes the shade of the fade out (sloped or curved)
  • High Pass - rolls off low frequencies
  • Low Pass - rolls off high frequencies

Just above the sound design controls, you are given a few additional tools:
  • A play button to audition the impulse response. The play button will only play what's visible in the waveform display. If you have trimmed the start or end of your impulse response, this will be reflected in the audio from the play button.
  • A readout of the current impulse response along with the duration of the response (this is updated live - trimming the start and end parameters will change the duration, which is useful for figuring out delay tail times).
  • A reverse button that reverse the impulse response, which yields in 'hauntingly' beautiful reverbs

*The only reason Fog Convolver didn’t receive a full ten out of ten rating in the feature section was due to it missing a few envelope parameters. We are given fade in and fade out controls, which are similar to attack and release parameters, but we are not given decay, sustain, or hold parameters that a few other competitor convolution plugins offer, which would add a bit of extra shaping of the impulse response.

Ease of use – 10/10

There are multiple aspects of this plugin that help define its 'Ease of Use," but the best aspect, in my opinion, is the live-updated waveform display. Each adjustment you make to the sound design controls is reflected on the waveform readout. If you change gain, adjust a fade in or fade out, or adjust some filters, the waveform will visually reflect those changes. Here is an example of this kind of visual feedback:

'Raw' impulse response

Impulse with fade in and adjusted end point

Having the waveform update itself live with the changes that are occurring makes tweaking certain parameters much easier. For instance, if there is something you dislike about the early reflections of a reverb impulse, you can grab the 'Start' parameter and visually trim the start of the file past the early reflections, then add a fade in to smooth the edit out.

Another cool addition is that the faders are calibrated for smooth operation. The fader movement to mouse movement is not a 1:1 ratio, but more closer to 1:2, meaning, the mouse has to travel further than the fader does, which gives you fine control over blending your wet and dry signals and stretching your impulse responses.

Bang for buck – 10/10

The price point is where I think this plugin really shines. AudioThing has priced Fog Convolver at 75 USD. With large-name competitors pricing their convolution plugins at three to four times the price of Fog Convolver, I'd say you can't go wrong. The amount of features bundled with the plugin make it well worth the price.

Bonus points:
  • CPU Usage - Fairly low usage for a convolution plugin (10 instances hitting 10-11 percent usage on my Intel i5 2.5 GHz quad core).
  • Expandability - There are thousands of free and paid impulse responses available online. While this is not an exclusive bonus to Fog Convolver, I feel it should be mentioned for anyone who hasn't used a convolution plugin before. You can greatly expand your impulse response library and get even more 'mileage' out of this plugin.
  • Drag and Drop Functionality - You can drag and drop 3rd party impulse response directly into the waveform display to use a new impulse response. Also, after editing an impulse with any of the parameters, you can drag the impulse response from the waveform editor out into your DAW if you'd like.
  • Extremely Responsive Developer - The only bug I found and reported in Fog Convolver was immediately identified and fixed within a matter of days - which is significant in the sense that it demonstrates the kind of passion the developer has behind creating a great user experience with his tools.

Total Score: 9.5/10

Drum Loop Demo:

Here in an example of a creative use of this plugin - using a sample of aluminum foil to make a 'reverby' type of sound. There are two loops of a drum beat. The first is with Fog Convolver bypassed and the second is with Fog Convolver active. I used an impulse response called Aluminum Foil 1 (included in the main library) and I adjusted the end point, added a fade out, and filtered out some low and high end. I filtered the low end to keep the bass frequencies from bouncing around and I filtered the high end to keep the wet signal from masking the dry signal, which also pushed it back a little bit.


In conclusion, Fog Convolver is an affordable, lightweight, and intuitive convolution plugin. It offers a ton of flexible parameters that allow you to really fine tune and edit impulse responses while simultaneously offering great visual feedback. You can send a vocal track through a telephone impulse response to create a low-fidility effect or you can send your drums through small room impulse response to give it some 'space.' The plugin really sparks creativity as the bounds seem to be almost limitless.