Originally Posted by jcmccorm
Interesting! You're doing ported farfield and sealed nearfield? I'm contemplating doing the same. I'm running sealed up front right now but have room for two full marty's up front with UM18's. What keeps me from doing it is the nearfield (JBLs) sealed. The Marty's do a phase switch by the time you get down to tuning right? How hard is it to integrate the sealed nearfield with that?
In my sealed treated theater (vs untreated living room theater thats open) I was shocked how much room gain I get down low. A LOT. So much it makes me wish I haad considered sealed all around, but then again I would need 10 or 12 big sealed subs to match just my farfield ported. Space considerations matter. I knew I had room gain, because the model vs sweeps showed some nice gain from 25 down to 10...but I never had a shot to get much below 10hz...and boom, nearfield subs away from all walls and corners have huge gain. I will post my measurements and integration at some point when I get up the nerve to figure how I can easily post pictures...maybe Im missing something but it seems way harder than just attaching a file.
If you follow the mtg90 strategy, you figure you have an existing farfield response, a new nearfield response, and then the combination of the two. You should test "how much" nearfield you want for days or weeks ahead of time before going to a final integration. If you dont, the integration may go on for months trying to tweak them together.
The challenege of integrating nearfield sealed to ported farfield is 2 fold -- does the spl increase as it should....AND...is the feel there?
The spl increase is easy to see of course. Measure farfield by itself, measure nearfield by itself, then measure both together. As you allude to, the rough integration without changing delay or phase will likely show mostly a big increase above the ported tune. The trick then is how to minimize the area where there is little or no gain. Phase and or distance will get you there. It can be challenging but it can be done well. In my case, from roughly 15hz to 25hz the sum of far and near is the same or a bit lower than the individual results, the rest is significantly higher -- above and below that range.
So spend some time trying different delays, phase settings and then once its optimized, you want to do some subjective feel tests. You will always feel your nearfields...but are the farfields making the feel better worse or same? If feel goes down you still have integration problems.
Once delays and phase are set, then you do EQ. NOW this sxxx gets way tricky --
If your response allows the nearfields to be in phase with the farfields, EQ should be easier, but still requires that you step thru each change one at a time. You want to fix that range between 15 and 25, you may need to boost one set, the other set, both....or, quite possibly reducing one source in that range will INCREASE output because they interfere in that range with those delay settings.
If they are out of phase with each other, it adds another layer which is....doing the opposite EQ you think in many cases!
Regardless, the process of EQ (if used) is best done one band at a time, solve one dip or peak at a time. Remember if boosting both results in worse response they are canceling each other there. I found this process fun and rewarding and easier than I though (figured might be impossible).
Im a measuring fool, I measure everything.
If someone is interested in my measurements, please give me easy step by step instructions to post them using my Samsung S8 or a Samsung touchpad. I used to post from my computer all the time but dont use it anymore and have a lot of troublefinding a place to just attach a picture file. LOL and yes I have a computer sciemce degree 😂 i have not tried tapatalk if that is better?