subject: Sound Reinforcement System Peripherals Tips - Sound Reinforcement System, Reverb - Sound Recording [print this page] : EQ equalizer and passive sub active equalizer, the next in a common passive equalizer as an example.
Room EQ is a Shanghai-wave band-pass device, is to adjust and improve the transmission characteristics of the Hall in the use of the frequency equalizer, which is characterized not only enhance the attenuation. Lu Filter is the third-order band-pass filtering, filter, each octave attenuation of 18dB. There is also a section nine octave equalizer, 1 / 2 octave 15-band equalizer, 1 / 3 band equalizer, the general attenuation are 10dB, 12dB, 15dB, 18dB several.
1, equalizer features: 1) of the Sound Frequency characteristic (curve) compensation (correction)
2) on the frequency characteristics of sound field frequency compensation
3) subjective structure of the processed sound and tone quality of the writing
2, the role of equalizer 1) improve the sound quality, adjust the spectrum curves.
2) improve the system signal to noise ratio, attenuation of noise bands.
3) elimination of acoustic feedback 4) to make up for deficiencies in the sound field to improve the listening environment.
5) modification, an important means of disposing of processed sound.
6) to meet different lovers in the hearing, the psychological requirements.
Second, pressure limiter (Compressor Limiter): It is the compressor and limiter general
1, compressor (Compressor): It is actually an automatic volume control. When the input signal exceeds the threshold value as the scheduled call normal times, the compressor's gain on the decline, the signal also is attenuated. In order to increase compressor level 1dB, the required increase in the number of decibels the input signal called the compression ratio or compression curve TOU rate. If the 4:1 ratio, increase the input signal 8dB, the output will increase by 2dB. Musical signal is due to changes in loudness, so the "" a moment may exceed the threshold level, and then another below the threshold level. Therefore, the signal exceeds the threshold level, the compressor reduces the gain, the input signal falls below the threshold level off after the compressor speed must be determined to restore the gain, the signal depends on the signal to increase the time and recovery time.
2, Limiter (Limiter): If the compression ratio is large enough, the compressor becomes limiter. Limiter is used to avoid the peak signal exceeds a certain level, to avoid amplifier, tape or disc overload. In extreme cases, compressor limiter is it any more than the threshold points, the top level of the waveform are cut off. Most limiters have a 10:1 or 20:1 ratio, they can use the ratio even up to 100:1. Limiter mostly used in recording situations, because many of continuous peak signal, we must raise the threshold and gain reduction using manual methods in order to limit the peak signal of extreme casual.
III Extender (dilator): Extend the gain as the input device is a different level and different special amplifier, which has an extended threshold, below this threshold will be upgrading the sound signal. When the signal level is lowered, reducing the signal gain, or when the signal level rises to improve signal gain, or both of the process is called "expansion", that is, when the signal level is low (below the expansion threshold ), the gain is low, program music Sound Degree was fading, when the signal level increased to above threshold, the gain on the increase, expander ring by making a more powerful signal, weak signal is weaker to increase the dynamic range of musical programs. Extender can also be used as a noise reduction device, you can make to remove the noise threshold in a predetermined point below the required signal is above the threshold point. Expander sound effects:
1, so that Music Signal generated strong rhythm
2, vibrato sound effects to show
3, so that music accompanied by drum rhythm sound, create special sound effects.
