Frequency Response Graphs - Advice Needed

[fireanimal]

Here are my Graphs, the Subs/Mains are crossed at 60hz. I applied a low shelf filter to lift the bottom end, and I applied one cut to the peak at 44hz. There is also a high pass Butterworth 18db/octave filter applied at 20hz.

My room is a 1150 cu/ft, dedicated theater room, with DIY corner traps, and treatments on the walls.

The subs are DIY 4xMJ18 in a sealed box that is around 16 cu/ft effective volume. I am driving them with a Crown XTI 1000, which is also what I am using for my filters and EQ, and works great as an all in one solution.

Questions.

On the sub graph there is a peak from around 70-100hz, am I correct in assuming to not apply an eq filter here, because it is also present in all the main channel sweeps .

Also should I be doing anything about the sharp dip that appears at 105hz, or is there really anything I can do?

I have adjust the delay settings for the mains, and sub, and the appear to be okay at the crossover, or could it be better?

If you notice anything else please let me know.

Thanks!

The Graph order is

1 - Sub no EQ
2 - Sub EQ'ed
3 - Mains Full Range
4 - Mains
5 - Sub and Mains

[brucek]

On the sub graph there is a peak from around 70-100hz, am I correct in assuming to not apply an eq filter here, because it is also present in all the main channel sweeps .

Lowering that area in the subwoofer with a filter will help when the mains and sub combine to lower the peak.

Also should I be doing anything about the sharp dip that appears at 105hz, or is there really anything I can do?

Nope. You won't hear it. Too sharp.

If you notice anything else please let me know.

I'm confused with the added curve you've given the mains target? There's really no necessity for it.
You've created a rather large sub house curve and then set your mains target so high that it is essentially negated.

Below is a pic of a bass managed 60Hz sub target overlayed with a 60Hz mains target and the resultant signal when the two are mixed in the room at 75dB. Do you see how the targets are quite a bit different than yours?. If I added a house curve to the sub target in the pic, it should rise from the crossover at 60Hz and shelf to the end frequency level above the 75dB target. If I added 10dB (which is a lot), I would end up at 85dB. You have an end target level to almost 100dB. You also have the shelf in your mains + sub graph starting at 80Hz, when your crossover is at 60Hz?


crossover 60 sub plus mains.jpg

I would shelf the house curve for the sub at 60hz and add maximum 8dB to about 30Hz. I would set all my targets at 75dB.

Your filters to smooth the response are great. You have a good response to start with though, as a testament to your traps and treatment.

brucek

[fireanimal]

There is no additional house curve applied to the mains, but that graph sure makes it look like there is, not sure if it has anything to do with the way the target line is interacting with the crossover?

My house curve is

40 14
80 0

You are right, I am not sure why I put in 80, when my crossover is 60

Also, the sweep was done at -20 dbfs, so the target is 85db.

Tonight I will redo the house curve as your suggestion 60 0 and 30 8, and filter out the other peak.

Just wondering if there is much difference doing the sweeps at 85 or 75? I thought that 85 would be better.

Thanks for all the help answering my posts today!

[brucek]

There is no additional house curve applied to the mains, but that graph sure makes it look like there is, not sure if it has anything to do with the way the target line is interacting with the crossover?

You must remove the housecurve file when testing the mains.

My house curve is
40 14
80 0

Yeah, 14dB is way too much, and 80Hz isn't appropriate (as you've acknowledged). Should be 60Hz.

Just wondering if there is much difference doing the sweeps at 85 or 75? I thought that 85 would be better.

Yeah, 75dB is the proper target to use. Set the level in the room at the listening position to 75dB, then run the SPL Calibrate routine and then run the Set Target Level routine and Measure.....


brucek

[fireanimal]

Ok here are the new measurements. The house curve applied is 60-0 30-10. I also posted a graph showing the Max Sub Output at my listening position.

[brucek]

Looks good, except if it were me, I would lower the area I highlighted by ~-5dB.

That extra 5dB hump will mask the 20Hz and below information somewhat.....


graph.jpg

brucek

[fireanimal]

Ok I will give it a try.

Thanks