Paducah Home Theater Posted January 10, 2016 Author Share Posted January 10, 2016 (edited) The thing about an array is directivity out to the seating area vs omnidirectional. All I know is that at any frequency that is halfway low like 25 hz and below, it will shake the hell out of my seats. I didn't have that before, I mean I had a little like on the transformers dinosaur stampede, but it was fairly specific. It sounded halfway flat down low and was very clean up high on music, but there was none of the grab you by the balls aggressive shaking feeling. That's what I don't get, there was a huge boost in this aspect, with no EQ, no additional amp. I'm not delusional enough to believe it has anything to do with my weak amp either. Edited January 10, 2016 by MetropolisLakeOutfitters Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted January 10, 2016 Author Share Posted January 10, 2016 man I wouldn't think it would make a big difference. But that 2" in depth could change frequency response. Like as far as placement I mean. Technically your woofers are 2" further out now. So that would slightly change where peaks and nulls would at theoretically. It's got to be something to do with room modes, that's the only explanation I can come up with. If anything, if you look at the modeling, my subs ought to be doing poorer with a smaller box, theoretically they do best down low with like 7 cubic feet sealed. And like previously mentioned the amp isn't exactly a Speakerpower. Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted January 10, 2016 Share Posted January 10, 2016 (edited) Changing box dimensions will change which frequencies in the sub band that are stronger or weaker. The rule on co-located sub, double the power, add 3 db, you also double displacement, add 3 more db. Now focus this in an array with forward directivity and it's like getting 9-10 db. Wow, that is a lot. This will occur without adding amps, watts, EQ, ect. This is one reason pick a sub by the low 3+/- point can get some people into trouble. They may not be able to tame the low end in a small room. This is more common problem with sealed subs. That's why when people ask which sub is best, sealed, vented, horn, it depends on the application. Either way, mission accomplished and with the MiniDSP, tune things to a flat FR and things will be golden. In the future I am going to talk about voltage more than watts. Voltage determine how much excursion (Xmax) you are getting which is a big deal when trying to get the most out of you subs/box combo. Edited January 10, 2016 by derrickdj1 1 Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted January 10, 2016 Author Share Posted January 10, 2016 (edited) Changing box dimensions will change which frequencies in the sub band that are stronger or weaker. The rule on co-located sub, double the power, add 3 db, you also double displacement, add 3 more db. Now focus this in an array with forward directivity and it's like getting 9-10 db. Wow, that is a lot. I feel like that's more in line with what I'm experiencing, down real low at least. Edited January 10, 2016 by MetropolisLakeOutfitters Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted January 10, 2016 Share Posted January 10, 2016 (edited) Guessing without measurements, hey. Vibsensor! Edited January 10, 2016 by derrickdj1 1 Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted January 10, 2016 Author Share Posted January 10, 2016 (edited) Guessing without measurements, hey. Vibsensor! I'm measuring right now, still have the expected room modes at 38 and what should have been 56 but its actually 53, they just don't sound as strong, it was worse without audessey before. Before when I had the inuke a simple 18 db/octave cut at 40 got it pretty flat. BUT, at 13 hz I'm only 2 db down from 24 hz and at 7 hz its only 6 db down from 24. Difference between 82 hz and 8 hz is only 4.6 db. That's no EQ or audessey or even receiver, straight into the sub amp. Edited January 10, 2016 by MetropolisLakeOutfitters Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted January 10, 2016 Share Posted January 10, 2016 Remember, room modes are determine by the size and shape of the room. They are fixed. Changing or adding subs or raising them off the ground will only slightly change how they interact. It is great if you don't have to boost down low: I wish that was the case in my room. I have always had to use a low boost. Easier to cut peaks than to bring up dips. Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted January 10, 2016 Author Share Posted January 10, 2016 Remember, room modes are determine by the size and shape of the room. They are fixed. Changing or adding subs or raising them off the ground will only slightly change how they interact. It is great if you don't have to boost down low: I wish that was the case in my room. I have always had to use a low boost. Easier to cut peaks than to bring up dips. That's the only reason I'm excited at all. I'm satisfied with the low end response, but I do still have some funk nasty peaks going on. Just trips me out because they don't seem nearly as obnoxious sounding as before, but they do look that way on paper. Quote Link to comment Share on other sites More sharing options...
JohnA Posted January 11, 2016 Share Posted January 11, 2016 How about the subwoofers NASA bought for sonic boom simulation? Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted January 12, 2016 Author Share Posted January 12, 2016 (edited) Flat to 5 hz, can't figure out how to measure below that. But, some nasty stuff going on up top. Haven't messed with peak spl yet, I can't even measure above 90 db right now. Not sure I'll be able to fix all that with a DSP, going to run out of EQ bands. That null at 82 hz is a PITA. Edited January 12, 2016 by MetropolisLakeOutfitters Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 12, 2016 Share Posted January 12, 2016 That null at 82 hz is a PITA. No sense boosting that frequency as all you'll do is eat up amp headroom. Do you have any bass traps? Can you move the listening (measuring) position? Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted January 12, 2016 Author Share Posted January 12, 2016 That null at 82 hz is a PITA. No sense boosting that frequency as all you'll do is eat up amp headroom. Do you have any bass traps? Can you move the listening (measuring) position? No bass traps yet, just normal panels. This was with the microphone on a little 6" stand sitting in the middle seat. Not sure where else I'd put it. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 12, 2016 Share Posted January 12, 2016 Not sure where else I'd put it. Doesn't matter. It'll measure differently wherever you move it. It's easier to move the seating position than fix a null. Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted January 12, 2016 Author Share Posted January 12, 2016 Seaton basically said the same thing, don't worry about 82 hz now, but maybe worry when the mains get integrated. Said the dip isn't fixable short of changing the position of the subs or which way they are firing. Even if I ignore it I've got multiple others to dink with. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 12, 2016 Share Posted January 12, 2016 don't worry about 82 hz now What will you cross your mains over at? Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted January 12, 2016 Author Share Posted January 12, 2016 don't worry about 82 hz now What will you cross your mains over at? Probably 60, I like it there. Between the LFE channel plus a 12 db/octave slope crossing over from the mains, they'll still see some 82 hz action though. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 12, 2016 Share Posted January 12, 2016 Probably 60, I like it there. Between the LFE channel plus a 12 db/octave slope crossing over from the mains, they'll still see some 82 hz action though. They'll see some but not as much as your mains will be putting out. A different location of 82Hz output (your mains) may affect the seating position response differently. 1 Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted January 12, 2016 Author Share Posted January 12, 2016 Probably 60, I like it there. Between the LFE channel plus a 12 db/octave slope crossing over from the mains, they'll still see some 82 hz action though. They'll see some but not as much as your mains will be putting out. A different location of 82Hz output (your mains) may affect the seating position response differently. My new mains are actually Acoustic Elegance subs so I need to make them earn their keep anyway. John is building them right now, its these three: Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted January 12, 2016 Share Posted January 12, 2016 If the mains are sealed, 12 db slope is OK, If vented, use 18 or 24 db slope. If the 82 Hz area is a concern, run REW with the mains and use 1/6 smoothing. To me, It does not look like a null or a problem. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 12, 2016 Share Posted January 12, 2016 You doing open baffle mains? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.