User manual ALTEC LANSING 291-16L HF DRIVER

[. . . ] 18 INFORMATION 1 2 WARRANTY INFORMATION . 19 2 Operating Manual-4048A digital signal processor The lightning flash with arrowhead symbol, within an equilateral triangle, is intended to alert the user to the presence of uninsulated "dangerous voltage" within the product's enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons. CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE COVER. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL. TO REDUCE THE RISK OF FIRE OR ELECTRICAL SHOCK, DO NOT EXPOSE THIS APPlIANCE TO RAIN OR MOISTURE. [. . . ] Bandwidth is adjustable from about 1/64 octave to four octaves, and the lower the bandwidth, the less audible the filter action will be. Finding the problem frequency is relatively easy, but finding the best combination of cut and bandwidth takes a little practice. Again, it is well worth the time getting comfortable with the notching procedure, so that problems can be quickly addressed with a sufficient but minimal amount of correction. 11 Operating Manual -4048A digital signal processor Shelving EQ filters: 1st order filters use a gentle 6dB per octave slope, while 2nd order filters use a 12dB per octave slope for more a pronounced boost or cut. All shelving filters have a boost/cut range of +/-15dB. Low shelving filters have a frequency range from 19. 7Hz through 2kHz, and the high shelving filters range from 3. 886kHz through 21. 9kHz. Shelving filters are most useful as 1st Order Filter broad tone controls to boost or cut the high 2nd Order Filter Low Shelf High Shelf end or low end of an audio signal's frequency +20dB content. Because they affect a wider spectrum of audio, they are not as suitable for +10dB feedback control as parametric filters. 0dB The EQ functions on all four inputs and eight outputs are switched in or out on an individual channel basis. In other words, each input or output has one "switch" for all of its EQ filters. If certain filters are not going to be used within a channel, simply leave the gain for that filter at 0. 0dB, and the filter will have no effect. -10dB -20dB -30dB 20Hz 200Hz 2KHz 20KHz 4048A Shelving Filters All-Pass filters: The all-pass filter type always has a flat frequency response but has a second-order phase response. The all-pass phase response is 0 degrees at low frequencies and -360 degrees at high frequencies and is -180 degrees at the center frequency selected. 7. 3e Routing Any of the four inputs can be equally routed, post input gain/EQ, to any or all of the eight output channels. Click on the <Routing> box for a given input and select the desired outputs from the list of check boxes. When a Bessel HPF and LPF of the same crossover frequency are summed, the combined response is +3dB for 12dB/oct and 18dB/oct Bessel filters, and -3dB for 24dB/oct Bessel filters. One of the outputs must be inverted when using either 12dB/oct or 18dB/oct Bessel crossover filters or else the combined response will have a large notch. Linkwitz-Riley The 12 dB/oct and 24dB/oct Linkwitz-Riley filters individually are always -6dB at the displayed crossover frequency, however the 18dB/oct Linkwitz filters individually are always -3dB at the displayed crossover frequency. The reason for this is that Linkwitz-Riley filters are defined in terms of performance criterion on the summing of two adjacent crossover HPF and LPF filters, rather than defined in terms of the pole-zero characteristics of individual filters. The 18dB/oct Linkwitz-Riley individually are 18dB/oct Butterworth filters in that they have Butterworth polezero characteristics and also satisfy the criterion for Linkwitz-Riley filters. When a Linkwitz-Riley HPF and LPF of the same displayed crossover frequency are summed, the combined response is always flat. With 12dB/oct Linkwitz-Riley crossover filters, one of the outputs must be inverted or else the combined response will have a large notch at the crossover frequency. 13 Operating Manual -4048A digital signal processor 7. 3g Delay In large installations or outdoor venues there are often many speakers in various locations to get the best coverage possible. Since sound travels relatively slow through air (1130 ft/s at 20ºC), multiple loudspeaker locations can create a situation where the original audio signal, simultaneously leaving all loudspeakers, arrives at a single point in the venue at several different times. Needless to say this causes problems, and what may be crystal clear sound directly in front of any one loudspeaker can be unintelligible at the farther reaches of the venue with direct line-of-sound to multiple loudspeaker sources. The solution is to delay the audio signal to the loudspeakers located further away from the primary source, so that sound comes out of the distant loudspeakers at the exact time that sound from the main loudspeakers arrives. Within the 4048A, up to 682 milliseconds of time delay are available on each output channel, allowing secondary loudspeakers to be time aligned with the primary speakers up to 771 feet (235m) away. Short Time Delay For Driver Alignment Example: 12 Inches Long Time Delay For Remote Speakers Speaker on Main Stage Secondary Speaker 200 ft from Main Stage High - No Delay Midrange Delay 12 Inches = 0. 9mS Low Delay 8 Inches = 0. 6mS A second application for delay is to time Same sound arrives at two different times. [. . . ] 7. ) Excessive Noise - An input signal level or an input gain setting that is too low could require the loss to be made up for at the output gain stage, producing more noise than a properly set up gain structure. Do not use the 4048A for dramatic increases in level, but rather optimize the signal source for a nominal 0dBu output. 8. ) Forgot the password - See section 8. 4 9. 2 RS-232 Troubleshooting Tips 1. ) Test all data cables. Use standard RS232 data cables with all conductors wired straight through. [. . . ]