This thread has been hugely informative for me. Just want to say thanks for all the great input.
Well that sucks. Yank the dash out and build a better one!Thanks to everybody in the know pitching in on this thread btw. Great stuff and I believe my biggest issue right now has to do with phase being my tweeter pods especially on the driver side a pillar blocks the mid in dash corner oem location.
Just my 2 cents, Take a close look at the most common boost you have in the above pic. It looks like you have about 6 EQ bands boosted up 3db's. If you increased the Gain on that channel up by 3db's, move the 6 bands back to 0db, that would free up those 6 bands on that channel for other adjustments....A very general rule, Cuts are better than Boosts.
The opposite to this… if you put an all pass filter on and it doesn’t improve summation that is the bad side, you add an all pass filter to the response to match the good sides phase to the bad side… this then improves summationIf you put the all-pass on one side and it makes things worse, that was the good side. Trial and error.
Although, if you can measure and view phase, it is quite apparent which is bad and which is good. In REW a good phase response (viewed unwrapped) will slope down gently from left to right, a bad phase response will deviate pretty significantly from that. All-pass filters will steepen the phase slope, so if the bad response slopes upward or less downward (than the good response), it gets the all-pass, if the bad response slopes more downward then the good response gets the all-pass to match it.
I think I should have called the "bad side" the "wrong side", good catch.The opposite to this… if you put an all pass filter on and it doesn’t improve summation that is the bad side, you add an all pass filter to the response to match the good sides phase to the bad side… this then improves summation
if you have a good phase response it will be smooth, measure a home audio loudspeaker with a close up mic approx a foot from the centre of the mid/tweeters centre is ideal and then look, what you end up with is a smile where bass and treble freqs leave the cone after the midrange… however a smooth phase curve is ideal
Nice cut and paste… not really relevant to this conversationAn all-pass filter is a filter that has a magnitude response of unity, but which provides a phase shift. You can use all-pass filters to tailor group delay responses in your signal-processing chain. You may find that you will need to cascade your filter with an all-pass filter to meet the group delay specification. A first-order all-pass circuit is shown in Figure 14.36(a). Note that this all-pass provides a DC gain of −1. If you want, you can cascade an inverting op-amp stage with the all-pass to take care of this phase inversion.