Alpine INE-W987HD Owners Manual English - Page 36

About the Crossover Crossover (X-Over): This unit is equipped with an active crossover. The crossover limits the frequencies delivered to the outputs. Each channel is controlled independently. Thus, each speaker pair can be driven by the frequencies for which they have been optimally designed. The crossover adjusts the HPF (high pass filter) or LPF (low pass filter) of each band, and also the slope (how fast the filter rolls off the highs or lows). Adjustments should be made according to the reproduction characteristics of the speakers. Depending on the speakers, a passive network may not be necessary. If you are unsure about this point, please consult your authorized Alpine dealer. Subwoofer (LPF) Rear speaker (HPF) Front speaker (HPF) Cut-off frequency (1/3 octave steps) HPF LPF ---- 20 Hz 200 Hz Slope HPF LPF ---- 0, 6, 12, 18, 24 dB/oct. 20 Hz 200 Hz ---- 0, 6, 12, 18, 24 dB/oct. ---- 20 Hz 200 Hz ---- 0, 6, 12, 18, 24 dB/oct. ---- Level 0 to -12 dB 0 to -12 dB 0 to -12 dB Low range Slope adjusting High range Output frequency range Slope FLAT Subwoofer Level adjusting (0 to -12 dB) Output frequency range Rear speaker Front speaker 20 Hz (Different from actual display) LPF cut-off frequency HPF cut-off frequency 200 Hz • HPF (high pass filter): Cuts the lower frequencies and allows the higher frequencies to pass. • LPF (low pass filter): Cuts the higher frequencies and allows the lower frequencies to pass. • Slope: The level change (in dB) for a frequency change of one octave. • The higher the slope value, the steeper the slope becomes. • Adjust the slope to FLAT to bypass the HP or LP filters. • Do not use a tweeter without the HPF on or set to a low frequency, as it may cause damage to the speaker due to the low frequency content. • Adjustment should be made according to the recommended crossover frequency of the connected speakers. Determine the recommended crossover frequency of the speakers. Adjusting to a frequency range outside that recommended may cause damage to the speakers. For the recommended crossover frequencies of Alpine speakers, refer to the respective Owner's Manual. We are not responsible for damage or malfunction of speakers caused by using the crossover outside the recommended value. About Time Correction The distance between the listener and the speakers in a car vary widely due to the complex speaker placement. This difference in the distances from the speakers to the listener creates a shift in the sounds image and frequency characteristics. This is caused by the time delay between the sound reaching the listener's right versus the left ear. To correct this, this unit is able to delay the audio signal to the speakers closest to the listener. This effectively creates a perception of increased distance for those speakers. The listener can be placed at an equal distance between the left and right speakers for optimum staging. The adjustment will be made for each speaker in 3.4 cm steps. Example 1. Listening Position: Front Left Seat Adjust the time correction level of the front left speaker to a high value and the rear right to zero or a low value. The sound is not balanced because the distance between the listening position and the various speakers is different. The difference in distance between the front left speaker and the rear right speaker is 1.75 m (68-7/8"). Here we calculate the time correction value for the front left speaker in the diagram on the above. Conditions: Farthest Speaker - listening position : 2.25 m (88-9/16") Front left speaker - listening position : 0.5 m (19-11/16") Calculation: L = 2.25 m - 0.5 m = 1.75 m (68-7/8") Time correction = 1.75 ÷ 343* × 1,000 = 5.1 (ms) * Speed of sound: 343 m/s (765 mph) at 20°C In other words, giving the front left speaker a time correction value of 5.1 ms makes it seem as if its distance from the listener is the same as the distance to the farthest speaker. Time correction eliminates the differences in the time required for the sound to reach the listening position. The time of the front left speaker is corrected by 5.1 ms so that its sound reaches the listening position at the same time as the sound of other speakers. 36-EN