Loudspeaker Crossover Design
Environmental Driver Control ™

      The goal of the loudspeaker designer is to extract the optimum performance from each driver while blending all drivers to achieve a flat frequency response and a stable, linear phase and impedance of the system.  Not only are a driver's frequency response and impedance determined by its construction and materials but they are also greatly affected by its "environment".  The internal volume of the enclosure, the shape and dimensions of a tuned port (if any), the amount of insulation, the mounting of the drivers, the shape and dimensions of the cabinet baffle, the shape and dimensions of the driver's frame, the location and orientation of the drivers on the baffle, the thickness and resonant properties of the cabinet, etc., are all environmental conditions affecting overall response and performance.  And this doesn't even include all the room acoustics.
The list goes on ...

      There are too many variables affecting the overall response of the system to mathematically predict end results from theoretical data.  There is only one way to account for ALL variables and that is to measure the frequency response (SPL) and impedance of each driver section when they are installed in their final environment, then blend the sections together using advanced computer optimizing software.  The "final environment" should even include appropriate placement of the speaker in the intended listening room, but we can't quite get that close to each customer on a production basis.  So we settle for anechoic measurements.

All D+S speakers are built with the following process:

  1. Electro-mechanical woofer parameters are measured by the LMS computer hardware system.  The data is imported into the LEAP computer software system to compute the optimal cabinet volume and port dimensions for deepest and smoothest bass alignment.
  2. The cabinet is built to completion with insulation and all drivers and ports installed.  Leads for each driver section (woofer, midrange, tweeter) are hung out the port for individual measurements.
  3. Using calibrated microphones and an anechoic chamber, full range high resolution measurements of on-axis SPL and phase sweeps are made using a computer hardware LMS (Loudspeaker Measurement System).  These sweeps are made for each driver section.
  4. "Near-Field" measurements are made at the woofer cone and/or at the port for low frequency response.
  5. Full range measurements of impedance and reactive phase are also made by the LMS system for each driver section.
  6. All SPL and impedance/phase measurement data is imported into LEAP (a software analysis and optimizing system).
  7. The conjugate networks are optimized to flatten impedance and phase of each driver section.
  8. The crossover (with conjugate circuits) is optimized to flatten SPL response to within +/- 2db.
  9. The crossovers are built using the high quality components.
  10. The speaker is tested and sweeps are re-measured with the crossover connected to each driver section outside of the enclosure to verify correctness.
  11. Each crossover is then installed and the speaker is fully tested and broken in.
This is our proprietary EDC™ process for building crossovers and we do it for every unit made!
This process ensures consistent ruler flat response with linear phase and precise imaging.
No "mass produced" store-bought speaker can ever come close.

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