The procedure for setting up a subsonic filter will vary depending on whether you are using a ported or sealed enclosure. Here’s a step-by-step guide for each type:
For Ported Enclosures:
1. Determine the Subsonic Filter Frequency:
– Start by checking the specifications of your subwoofers and enclosure. Look for the recommended subsonic filter frequency range provided by the manufacturer. It is usually mentioned as a recommended low-pass frequency or as a range (e.g., 20 Hz to 35 Hz).
– If there is no specific recommendation, a common starting point is to set the subsonic filter frequency half octave below the enclosure tuning or to around 80% of the enclosure’s tuning frequency for easier calculation (e.g., if enclosure tuning is 35 Hz, set the subsonic filter to 28 Hz. The tuning frequency can often be found in the manufacture’s enclosure documentation or specifications.
2. Set the Subsonic Filter:
– Access the subsonic filter settings on your amplifier, receiver, or dedicated subwoofer crossover.
– Set the subsonic filter frequency to the determined value from step 1. Adjust the control knob or enter the frequency in the settings menu, depending on your equipment.
3. Fine-tune the Subsonic Filter:
– Play audio material that typically contains low-frequency content, such as music tracks or movie scenes with deep bass.
– Listen carefully for any distortion or excessive cone movement that might indicate low-frequency signals below the subsonic filter frequency. If you notice any issues, gradually increase the subsonic filter frequency until the unwanted frequencies are eliminated but be cautious not to go too high and remove desired bass content.
– If your equipment has a slope adjustment, you can experiment with different slope settings to find the best balance between eliminating low frequencies and maintaining a smooth transition.
For Sealed Enclosures:
1. Determine the Subsonic Filter Frequency:
– Refer to the specifications of your subwoofers and enclosure, paying attention to the manufacturer’s recommendations for subsonic filtering.
– In sealed enclosures, the subsonic filter is primarily used to protect the subwoofers from damage due to excessive cone excursion. The recommended frequency is usually set to the lowest frequency at which the subwoofer can handle its maximum power without distortion or damage.
2. Set the Subsonic Filter:
– Access the subsonic filter settings on your amplifier, receiver, or dedicated subwoofer crossover.
– Set the subsonic filter frequency to the determined value from step 1. Adjust the control knob or enter the frequency in the settings menu, depending on your equipment.
3. Fine-tune the Subsonic Filter:
– Play audio material that typically contains low-frequency content and listen for any signs of distortion or excessive cone movement.
– If you notice any issues, gradually increase the subsonic filter frequency until the unwanted frequencies causing distortion are eliminated.
– It’s generally recommended to set the subsonic filter frequency slightly below the enclosure’s resonant frequency to ensure optimal protection and performance.
Remember to always refer to the manufacturer’s recommendations and specifications for your specific subwoofers, enclosures, and audio equipment. Fine-tuning may require some experimentation based on your listening preferences and the characteristics of your system.