making <100Hz flatter...

michael_w

Well I just started to play with this cool program called Room EQ Wizard and so I did some tests on my system. So I found a dip at 50 to 60 Hz. It was such a hole I was basically missing those 10 hertz. I managed to fiddle with the crossover, phase and gain settings on my sub to even it out a bit but it's still a big dip. Any good ideas on how to flatten the low end out a bit? I'm not worried about above 100Hz because the LSi's are pretty damn flat except for a little rolloff after around 15KHz. Here is the before and after graph. (second one is after fiddling)

btw my setup is:

nad c352 int amp
nad c540 cd player
polk lsi7's
diy ascendant audio atlas 15 in a downfiring ported box with a 350 watt creative sound solutions plate amp

I know this software is sort of made for adjusting an eq but I don't really have one. I was thinking there would be some kind of room treatments or something to get rid of that dip. I kind of find it odd because the LSi7's are known to have a hump at around 60Hz just before they roll off

gatemplin

How did you measure the room?

I assume you are crossing over at 100 Hz.

To fix a null like that you can either move the sub, the speakers, the listening position or build bass traps. An EQ wont help you at all. I dont believe that you can adjust phase with that amp either.

michael_w

I used that program to generate a signal from 20Hz to 150Hz. It basically uses the mic input of my laptop connected to a rat shack spl meter and then the audio out from my laptop into my integrated amp. I know results will be slightly different by switching sources like this but it's the only way that works with the program. The spl meter was on a tripod sitting on my recliner at ear level.

Well the first graph is with the phase set to 0, crossover at 50Hz; and the second is with it at 180, crossover at 70Hz. I tried all different crossover settings on the sub and 70 seemed to get it the flattest. I think I'll just have to mess around with placement of the front speakers (maybe move them closer to the back wall) and hope that helps.

gatemplin

That measurement method works fine. I've used it too.

Keep experimenting with placement and phase and then if it still isnt flat enough, look at some of the DIY bass traps.

Merry Christmas Michael

michael_w

I'm pretty sure that little 60hz hump starts to appear as the speakers get closer to the wall. I had them close for a while but didn't like it because of that hump. Maybe after some more adjustments I can push them back closer to the wall (about 3 feet away right now so I have room to go back) and maybe it'll help some. I'll run some more tests fiddling with placement and post some graphs later.

I've checked out the diy bass traps before and I'm not quite sure I have room for them. I might be able to put a couple in the corners of where my system is but other than that and the side walls I don't think it's possible. I attached a pic of the front of my room to help with any suggestions

btw that blue thing that stands around / over my system is my bed... it's a loft bed that stands probably 4-1/2 feet off the ground. Maybe that's one of the factors that's throwing a wrench in things?