Monday, January 07, 2008

More on Driver linearization

After listening to the Bressels standard filter for a few months, it is time for me to move forward to drivers linearization again with this filter. It took be 2 hours for the measurement and adjustment. During the linearization process, it was noted that the mid is actually quieter than the tweeter by about 6bB. After the linearization, the high is not as forward as before, the mid is clearly and the whole range becomes more balanced. The finer details is alot more easier to detect.

What you can see here is the frequence response of the whole speaker after driver linearization but without any other adjustment measured at the listening position. So, you are looking at the driver response + the room effect. You can see that the mid and high are quite smooth already. This is the part that is least affected by the room. There is a dip at the 200Hz of about 8dB. This is beacuse the woofer is not linearlized. The lower bass is also exaggerated giving a slight booming. All these will be corrected later on with room correction.

Also note that the lower cut off is now about 25-30Hz. Giving pretty good bass.

The above diagram shows the target curve I plan to use. This will be the first test, trying to make the target as flat as possible. Later on, I can make it to any shape I like. I can even exaggerate the mid range for vocals etc.

The next step I need to do is dirvers alignment. In the following graph, you will see the time domain of the driver response.

Now, you can clearly see the 3 spikes which represents the woofer, the mid and the tweeter not aligned properly. The sub reaponse is also hiding inside somewhere. With proper digital alignment, we should be able to get the spikes aligned.


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