OK, here are the initial results of inserting Rane PE 17 parametric EQs into my main channels.
First, I wanted to make sure that the Ranes did not add any noise or coloration. Here are the tests I ran:
1) Noise – Without the Ranes, I turned my system (600 watts bi-amped into each speaker) up all the way with no source input signal. There is no audible noise unless I put my ear a few inches from the tweeter and the noise is very faint. Next, I put the Ranes in the main lines and listened in bypass mode, then with all filters engaged and set to flat, and finally with the filters set to my intended positions. In all of these tests, the Ranes did not add any noticeable hum or additional noise.
2) Response – I used REW to measure the frequency response of the Ranes. In the flat setting with all filters on, the Ranes measures completely flat except for about a 0.25 db roll-off at the extreme ends. Then I played pink noise and switched back and forth to and from by-pass and noticed no change in sound or timber.
To create my filters, I used REW to create a filter file based on my prior room response measurements. Then I ran a sweep with REW through the Ranes and adjusted the frequency, level and bandwidth knobs until the response matched the virtual curves. This was important since the Ranes are analog and use knobs which can’t be adjusted with precision without using REW as a signal analyzer.
With the Ranes adjusted, I listened for a few days and was able to boost the sub a bit due and the sound is balanced. Sound is much improved.
Since I am just using the Radio Shack meter now, my next step is to remeasure with a Behringer ECM8000 (that came with my Velodyne SMS-1) and get a more accurate picture. Then I will tweak my lower end and experiment with house curves.
Any comments would be appreciated.
Here is the full-range response graph after using the Ranes and a small level boost to the subs.
second test b.jpg