Altec Lansing N-500 1970 - Green

The Altec N-500-C is a professional, passive, two-way loudspeaker crossover network designed to split audio signals, typically sending low frequencies to woofers (like Altec 414, 515) and higher frequencies to compression drivers/horns (like Altec 288, 802), using a ~500 Hz crossover point for balanced sound in theater/PA systems, often featuring adjustable high-frequency attenuation via buss bars. It's a robust, vintage component known for its use in Altec's Voice of the Theater (VOTT) systems, ensuring drivers get their correct frequency range for clear audio. Key Features & Function:

• Purpose: Divides a single audio input into low-pass and high-pass signals for separate speakers.
• Crossover Point: Around 500 Hz, ideal for 2-way systems with 15" woofers and horn-loaded compression drivers.
• Type: A passive network, meaning it uses inductors (coils) and capacitors to filter frequencies without external power.
• Components: Contains capacitors and inductors (and potentially resistors/transformers) to create the filter slopes (often 12dB/octave).
• Attenuation: Offers selectable high-frequency shelving/attenuation (e.g., 1dB, 2dB steps) to match different horns and drivers, configured with buss bars, not a switch like later models.
• Application: Used in large-format cinema, public address, and high-fidelity home audio systems. 

How it Works:

1. Input: An amplified audio signal enters the N-500-C.
2. Filtering: The internal coils (inductors) block high frequencies from the woofer, while capacitors block low frequencies from the horn.
3. Output: The woofer receives the low frequencies, and the horn receives the high frequencies, preventing them from interfering and improving sound quality. 

Vintage Context:

• It's a classic piece of Altec Lansing engineering from their professional audio era, often found in vintage sound systems.
• It's valued for its robust build and ability to integrate powerful woofers with distinct high-frequency drivers.