This weekend was dedicated to in-depth audio experimentation, specifically focusing on car audio crossovers. My exploration included listening tests with a Type A crossover (alongside previous tests with 4,500 Hz, 4000 Hz, and 3,500 Hz versions) and a custom-designed crossover based on the tweeter manufacturer’s recommended crossover point and slope. Both of these configurations delivered impressive sound quality. Personally, I found the tweeter performing optimally when connected directly to its own capacitor, rather than positioned in series after the input-to-autoformer capacitor.
Driven by curiosity, I decided to introduce the infamous AL crossover, commonly associated with La Scala speakers, into my testing setup. Initially, when paired with a low-wattage amplifier (one or two watts), the AL crossover’s performance was notably underwhelming. The audio output sounded devoid of life, detached, and generally lackluster. However, recognizing the importance of amplifier synergy, I swapped out the low-power OTL amplifier for a significantly more powerful vintage Hafler power amplifier, capable of delivering over 100 watts. This amplifier, known for its exceptional sound characteristics in suitable setups, completely revitalized the tonal presentation delivered through the AL crossover.
It’s crucial to remember that highly qualified engineers meticulously designed the AL network and made it available for a specific purpose. This suggests that the AL crossover possesses inherent potential to achieve remarkably high-quality sound under the right conditions. With the high-power amplifier in place, the AL crossover truly began to shine. The audio output was transformed, demonstrating a wonderful balance and surprisingly precise imaging capabilities.
However, it’s important to acknowledge the inherent subjectivity in audio perception. While the AL crossover, in conjunction with a high-power amplifier, yielded exceptional results in this specific experiment, my experience with other Single-Ended Triode (SET) and Output Transformerless (OTL) amplifiers (excluding my direct-coupled 300B monoblocks from last year) revealed a different story. In those cases, the La Scalas system did not perform optimally with the AL crossover, likely due to the complex network of inductors, capacitors, and shunt components inherent in its design.
Ultimately, this experiment underscores a critical aspect of achieving the best crossover performance in car audio systems: synergy with the amplifier. The seemingly “terrible” AL crossover, when matched with a high-power amplifier, revealed its capacity for balanced and high-imaging sound reproduction, highlighting the profound impact of amplifier pairing on overall audio quality and the subjective nature of audio evaluation.
