This week we’ll be sharing with you an Ableton Live set used for impulse response creation.
Requires: Ableton Live 9 or 10, MaxForLive, MaxForLiveEssentials pack.
It allows you to quickly capture IRs from effects (software or hardware) by dropping them onto a track and pressing a couple of keyboard shortcuts. Using the template skips the setup time, avoids having to fiddle around with routing, and prevents accidentally sending bursts of audio through your system, with the option to listen to the process if curious.
The set opens with three audio tracks.
•The first is named “Listen to Result” and is used to check out IRs after you create them, using Ableton’s Convolution Reverb plugin and whatever audio loops you desire.
•The next track is called “fx to measurer ->” and it’s where you place the effect you want to scan and make an IR from.
•The last track is called “<- measurer” and it’s where the IR measurement device is located.
•Decide how long the IR is likely to need to be.
For example, sampling a reverb’s tail fade will require a much longer time than sampling a cabinet’s frequency contour.
•Set “IR Time” parameter on the IR Measurement Device to a value high enough to capture the probable length.
To Measure Software (Plugins)
•Place the effect or effect chain you want to sample onto the “fx to measurer ->” track. It is usually recommended to be at 100% wet.
•Double-tap keyboard key “i” to send an impulse to the measurer.
(Alternately, double-tap “s” to send a sweep.)
•Wait for the measurement to finish.
•Check to make sure the “Current” time value is less than the “IR Time” parameter… if not, you’ll want to set “IR Time” to a higher value and try it again.
To Measure External Hardware
•Place External Audio Effect on the “fx to measurer ->” track.
•Set output & input channels for External Audio Effect as needed.
•Adjust input & output gains of External Audio Effect, if necessary.
•Double-tap keyboard key “s” to send a sweep to the measurer.
(Alternately, double-tap “i” to send an impulse.)
•Wait for the scan to complete.
•Verify that the “Current” time value is less than the “Sweep” time parameter… if not, you’ll want to set “Sweep” to a higher value and redo.
To listen to what the IR measurement device hears, slowly increase the Curiosity Return Track’s level. Be careful not to crank it so loud it hurts.
Saving and Review
Make sure to save your IR after you measure it with the key shortcut “v”, giving it an appropriate name. Afterwards, load it up in the Convolution Reverb device in the “Listen to Result” track, play an audio loop through it, and mess around with the “dry/wet” control. Hearing the result can verify how well the process worked and you can decide whether to keep the IR, try again with revised settings, or delete it and move on.
Where to Save? What i did is made a folder called “Organize” and stick them all in there. Then later i can place them into more appropriate categories.
How to Load? Simply drag the aif or wav file into the waveform window. In the case of true stereo (LR) IRs, drag one or the other, and it automatically loads the other half as well.
n trim & normalize
r results listener
Feel free to change these and save the set if there are others you prefer, or to map to a MIDI controller instead.
Q: What can IRs capture? What can’t they?
A: Think of an IR like a static snapshot. Modulations like LFOs and things like choruses won’t work; they might make a weird IR, but they won’t sound anything like the original effect and usually not very cool. Nonlinear processes like compression and distortion also won’t be captured. Decay tails (like from reverb or delay) and frequency contours, however, will be captured. So for example if you capture a guitar combo amp, you will thereafter be able to impose the cabinet’s frequency curve, but not so with the distortion the amp causes. Watch out for phase issues with IRs that only sample a frequency contour, when applied in parallel.
Sometimes sweeps (“s” key in our template) work better than impulses (“i” key). But sometimes the opposite is true. Try both and see which you prefer.
Likewise, generally the “true stereo” option works best for stereo effects. But sometimes the “mono to stereo” option yields better results.
Q: But what about capturing physical spaces with microphones?
As i don’t have much experience doing so, i’ll refer you to an external source: this “Recording Impulse Responses” guide from DesigningSound.org has some useful tips.
Free Elemental Spaces Impulse Responses
For use with any DAW, here is a hand-picked selection of 10 IRs from the upcoming Elemental Spaces pack by PerforModule, which i made using the IR Maker Template. The full Elemental Spaces pack will be including >50 IRs, each with a customized Ableton Rack preset as well.
These IRs are crafted out of my Elemental Mixing template racks (which i’ve mentioned various times previously). Each is calibrated as a starting point for a different track type, from instruments to busses to auxes. These IRs combine space and tonal elements of the processing chains, keeping the settings at their “go-to” foci and cutoffs. Since the results are pretty much a frozen snapshot of particular settings, they are fairly inflexible, but using Ableton’s Convolution Reverb device or other IR-loading plugins, one may modify the IRs to increase their versatility. They can be good for adding a touch of smoothness and sustain, helping to glue together overly dry, digital sounds that were crafted in-the-box.
Due to the dense nature of convolution, it’s recommend to start with half or less wet signal than you would normally use for an algorithmic reverb. Often, 5% is more than enough. Of course, if you’re using one in a return track to send audio to, you’ll probably want to have it set to 100%.
The free IRs are provided in LR aif form and include…
Guitar – Strat