Alesis 3630 manual Troubleshooting

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1.9 TROUBLESHOOTING

Noisy or "squeezed" sound- Too low a limiting threshold and/or too high a compression ratio can result in such problems as squeezed, un- natural sounds or excessive noise. Remember, limiting lowers the in- put signal's dynamic range. If the input signal has a dynamic range of 60 dB and you apply 15 dB of limiting (quite a lot), the dynamic range falls to 45 dB. This degrades the signal-to-noise ratio by an equal amount. A 60 dB signal to noise ratio can be acceptable; a 45 dB signal to noise ratio is audibly noisy.

If you encounter these types of problems, reduce the Ratio control or raise the Threshold control. Be careful; because the ear is not particu- larly sensitive to level changes, it is possible to add considerable amounts of limiting before it becomes obvious. Monitor the Gain Reduction meter to see how much limiting is being used, and adjust Threshold so that fewer LEDs light. Also, compare the bypassed and processed sounds to hear how much the 3630 affects the sound.

Some musicians use excessive limiting as an effect. Many of the mon- ster drum sounds you hear in records by artists like Phil Collins and Peter Gabriel are due to heavy limiting, followed by high-threshold noise gating to create an abrupt cutoff.

Noisy source signal- A noisy source signal may become more noisy when processed. Use the 3630's onboard noise gates to quiet a noisy signal.

Overall noisy operation- If the +4/-10 switch is set to +4, try setting it to -10.

"Choppy" or "jittery" sound- If the sound is choppy or jittery and the 3630 is in peak mode, increase the Attack and/or Release times. There are no fixed rules for optimum times since different instruments will work best with different settings. Generally, low frequency instruments such as bass will require longer attack times.

Dull attack- The noise gate Threshold must be turned as far counter- clockwise as possible (with the gate still operating) to catch initial attack transients. The gate may appear to be working with a wide range of set- tings, but if the initial transient is being cut off, the signal may sound dull or lack "life."

Attack and Release controls have no effect- The 3630 must be in Peak mode for these controls to be active.

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Contents Alesis Introduction Rear Panel Connections Hookup General TipsHere are some typical applications for Installation Hooking UP Power Front Panel COMPRESSOR/ Limiter ControlsPage Page Front Panel COMPRESSOR/LIMITER Switches Front Panel Noise Gate Controls Input/Output Meter -30 to +6 dBu Front Panel MeteringGain Reduction Meter -1 to -30 dB Side Chain Applications Noise Gate Meter Open or ClosedKeying Application Ducking Stereo plugFrequency-Dependent Limiting Application De-Essing Troubleshooting 10 3630 Specifications Appendix About Compression, Limiting, and Noise Gating LimitingAmplitude VS. Time Page Compression Noise Gating