Monday, June 25, 2007

4. Digital Room Correction

This is the last part of the setup and a relative easy part. There is a macro for it and for those who do not understand DRC, you can google for it as there are lots of information available already. Basically, you need to measure the sound produce by your speaker and measure that at your usual listerning position. What you measured include the sound from the speaker as well as the room response. The computer can now generate a filter that compensate for the difference. What different from EQ is that this works in both time and frequency domain.

In the above picture, you will notice that the red line is the room response and the green line is the filter.

Sunday, June 24, 2007

3. Driver alignment

The next step is driver alignment. Evwn when the drivers are aligned in a straight line on the speakers, the sound from the tweeter and the woofer may arrive to the listerner at different time depending on the height of the speakers and the height of the listerner. Some speaker designer design the speaker such that the tweeter is further back to compensate for this. However, this still does not account for the listerner's height.

Driver Alignment function allows personalization for each listerner based on their head position. The way this is done is to play a sound (logsweep) with a specified delay in time for the tweeter, mid and woofer. So the woofer is played first, the mid follows by 1000ms later and than the tweeter by another 1000ms later. After convolution, you will get the impulse response for all three drivers and the impulse response will be at different position in the time line. Now we just need to measure the distance between the impulse response and subtract the specified delay to get the exact time difference between each drivers.

As you can see from the picture above. The start of each driver can be seen and the distance between gives an indication of how to set the appropriate delay for each driver