AC 24 CROSSOVER
RANE AC 24 CROSSOVER a 4 vie
Buone condizioni estetiche e perfettamente funzionante.
Crossover a 4 Vie.
The AC 24 is a dual-channel four-way unit, incorporating 4th-order 24 dB per octave Linkwitz-Riley filters, signal delay, and limiting functions in a two-rackspace package. The channels can be linked for stereo operation, and the AC 24 can also be used as a dual three-way crossover, if needed. The unit incorporates DSP, yet has an analog-style user interface. This is refreshing in this age of click-and-drag operating systems, when a system without PC control (heaven forbid!) is preferred.
Each channel of the AC 24 has an overall level control and clip indicator LED, low, mid, high-mid, and high output level controls, mute switches for each range, limit controls (and low-limit link switch) with threshold indicator LEDs for each range, and 0 to 10ms delay controls for each range, as well. Crossover cutoff frequency controls lie between these ranges; they are adjustable from 31.5 Hz to 315 Hz, 160 Hz to 1.6 kHz, and 1.25 kHz to 12.5 kHz, respectively. A defeatable constant directivity (CD) horn EQ is included, for high-mid and high-frequency horn adjustment, with control of each from 2 kHz to 8 kHz.
Finally, a low frequency mono summing switch and stereo link switch complete the front panel topology. As one can see, a very extensive set of operational parameters.
The rear panel jackfield includes panel mount XLR female input jacks for channels A and B, individual XLR male band outputs each with polarity switches, and XLR male sum outputs for each channel. Input impedance is a high 7.33kohms, and output impedance a low 100 ohms, which makes for good impedance matching with most equipment. The three-way/four-way mode selection switch is at the bottom left, near the IEC power cord connector. The AC 24 uses an internal power supply, as opposed to the wallwart style units found on some other Rane products.
Obviously, for correct setup of a crossover such as this one, which has so many fine-tuning capabilities, an audio analyzer is necessary. For example, with a multi-way enclosure, you may not have the specifications for the individual drivers within the box. An analyzer can help determine where the drivers roll off. Setting gain for individual drivers requires a dB meter. If you are unsure of the acoustic centers of the drivers in the box relative to each other for the purposes of delay adjustment, an analyzer can help in this way, as well. Suffice it to say, that if you are unclear at all about any aspect of a multi-way enclosure that you intend to crossover electronically, an analyzer gives you an edge.