[Danny Richie]

Sounds like it is not a directional mic. So with it aimed vertically you may be picking up reflections from the rear of the room as well (behind the listening position). I'd try it aimed at the speaker.

[mojave]

All mid-room, 1m measurements were taken with the mic pointed at the speaker. I thought you already discounted the measurement with the mic pointed at the ceiling because it was taken from the listening position with the speaker in its normal place. 

The purple trace in the first chart in post #17 is taken with the X-Omni in the center of the room with the microphone horizontal and pointed at the top of the speaker at a distance of 1m as you requested.

The second chart in post #17 was also taken with both speakers in the middle of the room with the microphone pointing at the speakers.

If this was the first speaker to ever have in my room, I would have thought it was room interactions. However, I have measured 3-4 other speakers in the same location. I've also measured a Hsu VTF 2 Mk1, VTF 2 Mk3, VTF 1, MBM-12 and dual av123 MFW-15's. I have ran all these subwoofers at full range just to see how they interact with the room before assigning the crossover. None of the speakers or the subwoofers (which usually extend up to at least 200 Hz) show the dip that the X-Omni has. Is it possible that the X-Omni interacts with the room differently since the driver faces upward? I'm still learning about room acoustics.

[Danny Richie]

Okay, here is one of my thoughts.

From the woofer to the inside bottom of the box is 28.75". So from there back to the woofer is 57.5". The equivalent wavelength for that distance is about 220Hz (possible cancellation).

So I wonder what they did internally for damping material?

Mind pull out the woofer and taking a peek?

[mojave]

I'd be glad to pull the driver and look inside. My torx driver is already sitting on the desk. I'll do it this evening when I get home.

[mojave]

I removed the grill and driver last night. The interior of the speaker is lined with 1/4" to 1/2" felt. It covered all the sides and was even wrapped around the back of the tweeter.

I thought back to my initial listening of the X-Omni and remembered that I had used my Onix SP3 for full range listening (I had just biased it). Maybe my SP3 is weak in the low end with the current tubes. I then hooked up the X-Omni's to my Outlaw Audio 7100 and listed with the subs for several days. Finally, I took full range measurements of the X-Omni's with it hooked to the Outlaw amp in order to calibrate with the subs.

Last night I listed for a half hour (my wife said it was 45 minutes  ) to the X-Omni's in full range with the Outlaw amp. The bass seemed much fuller than with the SP3. However, I don't think the low end is as good as the ELT525T's. I really like the X-Omni's presentation of space, separation, and soundstage.

Back to the measurements, I still can't figure out why the bookshelf and the X-Omni's measure differently from the same location. What would happen if I measured the X-Omni's with the driver vertically (but still about 4ft off the floor)? I wonder if my initial impressions with the SP3 are affecting my interpretation of the graphs in any way.

[emac]

Last night I listed for a half hour (my wife said it was 45 minutes  ) to the X-Omni's in full range with the Outlaw amp. The bass seemed much fuller than with the SP3. However, I don't think the low end is as good as the ELT525T's. I really like the X-Omni's presentation of space, separation, and soundstage.

In my experience w/ the Omni's as well as the O-3's, it takes some experimenting to get the bass sounding right.  The position I've used for non-omnidirectional speakers seems to suck some out some of the bass w/ the Omni's.  I have to move the Omni's forward at least a 1/2 foot for them to start to sound right.  Either way, the bass of these speakers is not quite at the level of other speakers.  They aren't going to be able to kick you in the chest, even with a sub.  The strengths are the "presentation of space, separation, and soundstage". 

[Danny Richie]

My listening impressions of the SP3 is that the bottom end is really soft and weak.

Still, I think some of the issues that you are having are room related, as the on axis measurement looked good.

Thanks for the feedback on the insolation. I'd try adding a dense layer of something to the bottom of the box all the way up to the ports and a couple of inches back from the port (up into the chamber of the port) and see if that doesn't give some bass back. I suspect that there is some standing wave cancellation going on through the box as the distances appear to line up with the wavelength.

[fcraven]

All this discussion begs a question for me. What software or whatever are you using to test your speakers? This might be worthy of another thread, or perhaps there is another board. I would like to test my speakers in their location to see how they are doing, and it might help in the balancing of the subwoofer as well.

[mojave]

Thanks for the feedback on the insolation. I'd try adding a dense layer of something to the bottom of the box all the way up to the ports and a couple of inches back from the port (up into the chamber of the port) and see if that doesn't give some bass back. I suspect that there is some standing wave cancellation going on through the box as the distances appear to line up with the wavelength.

The port is at the bottom of the speaker. I think there are only a couple of inches between the bottom of the speaker and the port. Are you saying I should put some polyfill into the speaker up to the port? Or should I try to put a piece of NoRez at the bottom? I'm not sure I can reach that far. I don't think Skiing Ninja's NoRez kit for the X-Omni includes NoRez for the bottom chamber.

All this discussion begs a question for me. What software or whatever are you using to test your speakers? This might be worthy of another thread, or perhaps there is another board. I would like to test my speakers in their location to see how they are doing, and it might help in the balancing of the subwoofer as well.

I am using Room Equalization Wizard (REW), a Behringer ECM8000 measuring microphone, and a Tascam US-122L as the preamp/phantom power. You can read more about it at the REW Forum at HomeTheaterShack.com.

[Danny Richie]

Try filling up the bottom of the box but still leave a clear path to the port. Fiberglass insolation or polyfill will be fine.