Something is amiss

[Ryan_M]

Maybe it's me, or user error... I don't know.

Below are the results from my trial tonight. I measured the mains as well to make sure that I got the sub level correct. I'm not sure why the mains are extending a little deeper than the 'ideal' response. They were built ported and ATM I have a rolled up sock jammed in the ports. Maybe that's what a leaky box response looks like? I took a stab and made a 10db hard knee house curve, just a shot in the dark guess. From the instruction on how to set one up looking for 30Hz to sound the same volume as the XO frequency (100Hz in my case) I came up with a value of ~8db so erred on the side of caution and gave it a little extra, maybe the wrong thing to do.

As far as what I know to look for in the graphs I'm reasonably close to what I should be doing. After getting those measurements I setup to listen to some music which involves swithching the PC's audio out put to digital (Iuse coax digital) and setting the A/V receiver to coax digital input. I played U2 'Still haven't found what I'm looking for' since it's kind of a bassy track and the bass guitar is barely audible. Turning up the volume to as loud as I care to for midnight the subwoofer is only moving ~1mm and other tracks confirm that there's nearly no bass output.

FWIW when doing the frequency sweeps in REW The sub was really moving, the couch was vibrating, and the dogs and gas fireplace didn't like it much either and I was expecting the SWMBO to come tell me what she thought of that.

Any suggestions on what's going on?

[robbo266317]

Have you tried reversing the phase?
Also a sweep of mains + sub may give some clues as to what is going on.

[Ryan_M]

robbo266317 wrote:

Have you tried reversing the phase?

I used the RTA + pink noise to adjust the phase on the sub amp to get the best response at the XO frequency but I'll double check.

robbo266317 wrote:

Also a sweep of mains + sub may give some clues as to what is going on.

I'll do that.

[Ryan_M]

After running RTA again I did a little tweak on the phase but nothing substantial. Here's the full system sweep. BTW I included one with no filtering and one with 1/3 octave filtering, not sure which is prefered. That nast null is there on the sweep of the mains by themselves, I think the graph I posted above was using filtering (obviously).

[robbo266317]

That certainly looks like a good response.
I cannot see why the bass should be weak?

[Wayne A. Pflughaupt]

I'd tend to agree, at least nothing that turning up the sub a bit wouldn't fix. Unless something's happening here that's not immediately obvious (emphasis added):

Ryan_M wrote:

After getting those measurements I setup to listen to some music which involves swithching the PC's audio out put to digital (Iuse coax digital) and setting the A/V receiver to coax digital input.

Regards,
Wayne