REW not displaying under 22hz

[AudiocRaver]

When diagnosing a new "problem," backing up a step or two to a point where there was no problem is always a good move. Let us know what you find.

 

[jtalden]

I just thought of something...we lowered the gain on the woofers by 8db due to the huge peak around 100hz. I wonder if that is why we have the null higher up...I think I will raise it back up 8db and see if that is the problem.

The reason Inasked about the low phase growth is that is how mine are tuned...no set crossover frequency...all done with the Xilica filters.

You can check the ideal phase impact of any filter as shown below. I loaded a ideal impulse as a measurement and then set a -8 dB, 100 Hz, 5.6 Q In the REW EQ window to see its impact. It looks like there is about a ±26° phase impact of that filter.

You can also see the impact on the actual measured response this way. Just set your filters and and view the resulting phase impact on the measured response.

Also:
Your current XO delay timing is not very favorable. It is low in phase rotation, but due to the delay timing the SPL support in the XO range not favorable. Just inverting the polarity of the woofers would be much more favorable for SPL support, but would increase the total phase rotation slightly. It is likely that a delay change alone would result in the same SPL support, but retain the low phase rotation. I did not save the analysis yesterday so I don't have specific changes to share. If you like, I can run the analysis again and provide a couple of options.

 

[NBPK402]

Thank you, I will upload my current settings so you can see how it is set too. I remember when you set my JBL 2360As up and they sounded great!

 

[jtalden]

I need the same 3 measurements as in Post-21.

You can make these measurements with mic maybe 1 to 2 m distant from the speaker. There is no need for the acoustic panels.

 

[NBPK402]

The one you are referring to was from the mlp with the mic pointed upward with the acoustic panels like they are when I normally listen, and the curtains shut.. So I should this time do it 1m from the horn, and have the mic pointed at the horn with a fullrange REW run, correct?

Also the gain raised back up to where it was before, correct..which was no added gain?

 

[jtalden]

Place mic in front of the speaker at about 1 or 2 m. I can still do the job if the mic is at the LP so that is okay also. It is just a cleaner measurement when the mic is closer.

You can point the mic at the speaker or vertically. The orientation will not impact the measured phase or delay change needed. The mic orientation does impact the high frequency SPL so if you intend to also look at that for EQ or other reasons then point the mic to agree with the mic calibration file being used.

The other room settings like the panels or curtains have no effect on the phase and delay of the direct sound that I will be using.

The gain is best set near where you intend to set it for listening. That is, it is best to not have a very large difference between the bass and mid ranges. You can leave any EQ setting that you intend to use if you like. They have only a trivial effect on the results. I sometimes defeat the EQ filters in the XO range, but do not consider this mandatory.

 

[NBPK402]

The only thing I did was switch the bass gain back to where it always was before, and move the Acoustic Panels back to where they normally are and raised my mic stand up to be at the center of the horn again. Interesting that the large peak and the dip are gone again. It must be the AT panel box i was using. If there is anything you can do to help me get my bass up down to 20 HZ to be closer to the rest it would be appreciated. When we had the JBL 2360As with these drivers we ran a 10 or 12db high shelf around 10k as I recall, but the room was nowhere near as live as my current one is...not sure what would happen if i used one again. All distances, YPAO volume, and levels are factory default. YPAO has not been run and there is zero eq done. at this time. I have a MIniDSP DDRCA88 that I will setup once all my speakers are ready.
REW screenshot is Red Left and Right green... I sure wish my left was as good as the right. I also am posting the old vs new right channel.

Whatever suggestions you have to tune it...lease let me know how it will effect the system. I def would like to get more bottom end without getting muddy.

I gave you the Xilica settings too so you can see what they are currently. I am also working on a 2' cube version of this horn that will use the same parts except it will be wood. Not sure if I will have to start from scratch or be able to copy these settings over zand then adjust them.

 

[jtalden]

Post-32 appears to be concerning EQ settings. I was not offering to review EQ and to make recommendations. That is to difficult to do offsite.

I was offering to review the XO delay timing currently set between the woofers and the CD. The 3 needed measurements are the the ones in Post-21; R-Woofer (alone), R-CD (alone) and both together.

The XO timing of Post-21 did not look favorable to me for SPL support across the XO range. If the current delay settings are in Post-21 measurements If you do change the XO delay timing it is likely that the EQ in the XO range would then need to be adjusted accordingly. There is no problem in just leaving the current delay settings if you like. Improving the timing of the XO is not likely to have a very significant impact on the sound when the SPL is adjusted similarly.

Let me know if you if you still want me to suggest an XO delay timing change. I can do that either using the Post-21 data or with new measurements.

 

[NBPK402]

Thanks, If I recall correctly only filters were used and the tuner said it did not need any delay settings due to the nature if the design. I uploaded the crossover settings so you could see how this was done.

I think I am going to try running each woofer through its own crossover and see if rhe woofers are measuring the same. My left channel when I run REW give me a chattering sound at the very beginning of the run...none of the other channels do that. Maybe I can figure out which woofer it is by muting one, and if it is 1...then I will pull another one I have still jn the box, and see if it solves the problem. My thinking is that if the woofers are not matched properly or are not soec'd the same it might cause the loss of bass from the left channel...compared to the right. Does this make sense?

 

[jtalden]

That makes sense. Running each woofer alone is a good way to determine if it is causing the chattering and loss of bass.