You can safely use one recorder to play back the sweep and another to record. The Altiverb sweep method is immune to clock differences between playback and recording gear. The sweep is not equal loudness throughout, its level is higher where most speakers can take it and where the ear is more sensitive, resulting in less noise. There are many advantages of using the audio ease method of creating impulse responses. Altiverb will assume that you have used a quality speaker to play back the audio and will not attempt to make up for any frequency deficiencies of the speaker. When this quality speaker option is selected The sweep tone will be calculated out of the recording and you will hear the resulting reverb right away. The resulting recording can be dropped onto Altiverb. Microphones should be used to record the playing back of the sweep tone in the room. These are meant to be played back in a room of which you want to capture the reverb in an impulse response. Sweep played back through a quality speakerĭownload sound files that contain a sweep tone from this page. To make up for that you can use the enhance knob which is a pink-to-white EQ and can bring back the high frequencies. Convolute them, which is a multiplication in the frequency domain, and you will see the roll-off slope is twice as steep. Pink means the high frequencies roll off at a certain very natural rate. In audio, the piano has a ‘pink’ distribution of frequencies. It does become purple, but it also becomes rather dark. What happens when you use a piano chord as an IR and then sing through Altiverb, is much like what happens when, in lighting, you want to use a blue and a red translucent filter to create a purple one. You need to really boost high frequencies. Using audio like piano or voice normally results in material that sounds too dull. Whenever you like an impulse response do not forget to save it using the save to User IR folder button. Select this item, drop the audio and listen to the result. Special effects can be achieved by using audio such as piano chords, breaking glass, spoken word, or drum rhythms. Select this if the audio you are dropping is a finished impulse response (downloaded from somewhere, or obtained using a digital spike recording through effect gear), or if you want to experiment using other audio.
When recording odd places like tunnels, shafts, pipes or other resonating places or huge stuctures (like stadiums) you might want to consider choose the next 30s sweep with 45s of silence after it, to capture a longer reverb. The 16 seconds is good maximum reverb time for normal rooms and halls.
The 30 second sweep gives a (more then) great signal to noise ratio, bypassing any noise from the recorder, pre-amp and mics while 30 seconds is still short enough to hold your breath and ask people to stay quiet (very practicle!). This also is the one Audio Ease uses most of the times sampling rooms.