As a continuation from this thread i want to discuss my efforts in integrating sub to midbass and midbass to tweeters.
As my phase cohesion wasn't that good, clearly to see in the aforementioned thread by not summing of 6db in my crossover regions, i decided to start from scratch. Yes, from scratch, means EQing, level matching drivers, and then adjusting time delay from my baseline (through tapemeasure) to have better summing at the crossover.
For the speakers see my sig.
This time the crossovers were chosen as follows:
Sub: Lowpass 63Hz LR24db, Level in DSP: -4.5 db
Midbass: Highpass 63Hz LR24db, Lowpass 2500Hz LR24db, Level in DSP: left 0db, right 0db
Tweeters: Highpass 2500 LR24db. Level in DSP: left -8.5db, right -6db
DSP used: Mosconi D2 100.4 DSP (DSP amplifier).
I use a custom curve made with Justins Spreadsheet.
Results from EQing and level matching are in the following screenshot.
You can see the slopes follow the LR24db alignment almost perfectly. Almost, as there is a 0.5-1db difference in some areas.
Problem: when entering the time delay values from Erins calculator (and Jazzis, but result is the same) i only had 3db summation at all crossover points for all drivers (using a screenshot where my sub-midbass xover was at 80Hz, but result is the same between both. It's just for demonstration purposes. Sub is missing in the screenshot, but it had only 3 db of summation just like the midbass to tweeters).
Now i did the following.
I entered the initial delay values for my midbass and tweeters:
Left Tweeter: 2.31ms
Left Midbass: 1.17ms
Right Tweeter: 0.83ms
Right Midbass: 0ms
Sub: 0ms
After that i added 10ms of delay to all drivers, muted the tweeters (have to do the fine adjustment for the tweeters still) and removed delay from the subs in 0.4ms steps and measured with periodic pink noise.
At one point i had a big dip in the response. At that point i stopped and added an amount of delay that equals half a wavelength of 63Hz in time (think it was around 15.87ms, so i added half of that: 7.94ms) and then i lowered the delay of all drivers uniform until the delay on the subs was at 0ms again.
This brought me to the following time delay settings and the following summation in the sub-xover:
Left Tweeter: 13,82ms
Left Midbass: 12.64ms
Right Tweeter: 12.36ms
Right Midbass: 11.56ms
Sub: 0ms
Looks a lot better, but still missing around 1db of summation.
I haven't yet measured both midbass drivers together, nor tweeters together, as i want to get each side done first as good as i can.
Now, would you go for that last db, or would you call it a day and live with it? Is this missing 1db really due to phase or can i savely eq this by minor adjustments in the xover region?
Is my way of doing all this like i'm doing it right now valid at all?
Next on my list is the midbass/tweeter crossover integration. I'll follow up with that in another post in this thread, but right now the plan is to do it like with the subwoofer, i.e. add some delay and then substract delay from midbass and sub until i have cancellation and then flip phase on the midbass back to 0db.