![]() The sweep is in mono, so you will likely find the phantom image to heavily go off-center at specific frequencies, an indicator of some L/R asymmetry in your setup (typically not easy to nail down what it causes it, though).Ĥ) THE STRUCTURE OF THE BURST SEQUENCES, for each specific frequency: So if you hear a drone or a suck-out or any other interesting stuff at, say, 00:23 and 1:12, the corresponding detail sequence tracks are track #23 and track #72 (60+12). The sweep is timed such that the current position (in seconds as displayed) by the player indicates the track number of the corresponding sequence for the current frequency we're at, in the sweep. Wait and watch woofer's motion before you decide to turn it up! The track has 3 seconds of silence at the beginning, afterwards the low rumbling of 27.5Hz starts without warning.ĭON'T TURN UP THE VOLUME because you think at first it were too low to hear the low tone. You might already notice some frequencies "sticking out".ģ) Play track #2, the sweep. If you happen to get bit by the "burst bug" you may find yourself listening for many hours, especially when you start to move your speakers and listening position around.Ģ) Now start with the first track, the noise, to set a rather low listening level and for general verification that your setup is working well. Make sure your speakers are really off before turning up the volume of the phones!! Don't overdo it as you might damage your phones also and your ears will thank it, too.įor the first time of usage you may want to reserve at least an hour for testing. Start with a moderately low frequency like track #23 (49Hz). To make yourself accustomed with the CD's signals, you might want to listen to some tracks at first with headphones to memorize the target sound of the patterns more easily. You should be in a relaxed state of mind and the environment should be quiet but not dead silent - some background random noise is helpful to better detect the structure of the modulations because of the psychoacoustic compression effect the noise gets masked away by the LF signal in the specific patterns thus making them more readily audible. The CD uses all 99 tracks allowed by the CD standard which any CD-player should be able to handle. HOW TO USE THE CD (or the signals in general)Ī CD-player with CD-Text option for track name and a remote control is most convenient for usage of these test signals. Low Frequency Sine-Burst Test Signals for Room and Loudspeaker Evaluation. Source and executable files (Windows) for the C programs used to make the original. You don't want to waste any effort on navigation since the main task is well-focussed concentrated listening.ĭownload Link (containing a bunch of FLAC files, some instructions and a GIF for a CD index sheet). Using a remote control of any sorts which can be blindly operated, to quickly navigate through the tracks with instant playback starting after a "next" or "previous" select, is paramount for convenience and success. The usage was optimized for CD-players (preferably capable to display CD-text info) with remote control because other digital playback sources also weren't commonplace. These are specifically designed burst sequences, ranging from 27.5Hz to 440Hz, spaced in quarter-note distances. This was a project I did 20 years ago before EQ'ing was commonplace, let alone full digital "room correction".Īn important feature was that I tried to highlight the temporal distortion that comes with room modes, something which cannot easily be evaluated with steady-state sine test signals. Recently, I promised I'll present my trusted test signals for evaluation of room modes, finding best positions for speakers and listener, check for distortion/rattling etc.
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