Check the listing for details. Pioneer HPM-60 Crossover - upgrade service. Listed at 299.00 USD. Re-design of the original HPM-60 crossover. The original crossover had a high pass filter on the midrange and on the tweeter, in effect the midrange was reproducing frequencies as the tweeter. The new design uses a bandpass filter on the midrange limiting the high frequency output where the tweeter takes over. The woofer crossover is also modified and updated implementing a Zobel network and 1200 Hz, so the new crossover points 1200Hz, 4000Hz, 12000Hz with each driver performing it's best at the specified frequency. This takes the HPM-60 from being a HiFi sound to more of an Audiophile level. **This is for a pair of crossovers. You need to send me your crossovers for the upgrade. **-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Customer Feedback:Wow, there are no exaggerations here, these grabbed my HPM-60s by the balls and made them sing. They are more clear, have more low/mid rumble, and sound more impressive in general. Even the speaker wire connections were upgraded! 10/10 would do again. Highly recommended!--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------So far, SOOOO good! I can definitely tell a big improvement in clarity and overall quality. Patrick even upgraded the speaker outputs from the original push-spring type to legit banana plug-style terminals! While these were being done, I did my own improvements to the cabinets (inside & out) and also resealed the subs. Reassembled everything yesterday once I got the crossovers back, and my mind is blown. A++ work. Thank you!!