Post-correction measurements

[abdo123]

Dirac room calibration using my target curve of preference, 19 measurements Spatial average.

Spectrogram at listening position before and after

SPL Sweep at listening position before and after

 

[thewas]

Dirac room calibration using my target curve of preference, 19 measurements Spatial average.

Nicely smooth response even before correction, which loudspeakers?

Spectrogram at listening position before and after

Please note that the dB colour scale on both is different, something annoying in REW which needs to be corrected by hand to make them better comparable.

 

[abdo123]

Nicely smooth response even before correction, which loudspeakers?

JBL Stage A130 with Maiky's EQ and two time aligned subwoofers in mono. This is my living room setup.

Please note that the dB colour scale on both is different, something annoying in REW which needs to be corrected by hand to make them better comparable.

I usually look at how 'smooth' the peak energy time dotted line is, thank you for bring it up! I will correct it.

 

[Kal Rubinson]

Thanks. So assuming top of line system components but not using separate systems for stereo and multichannel, about the best one can do then is then is use REW to try to optimize speaker locations, room treatments, and listening positions for smoothest response below Schroder frequency and optimal listening window for high frequencies. Run Dirac and cycle through all listening positions, finishing at prime listening location, save several filter options, then without changing mike position, REW with and without Dirac, match speaker levels, for each of the chosen filter configurations. Do this for stereo, stereo with subs, and multichannel presets. Or am I over thinking it?

I think so. I have a well-defined mic placement for the center of my head which I use for the first measurement position for Dirac (or others) and it is also the position I use for pre- and post-EQ measurement with REW. That's it.

 

[Jbrunwa]

Ok. Here is what I see on my mains with subs, with and without Dirac. This is what Dirac Live shows with 13 positions, and REW at main listening position with 1/12 smoothing (Blue = Before and Red = After). Does the SPL for the subs seem too high compared to Dirac measures, or are we saying that if we were to average 13 positions with REW we would measure levels similar to Dirac?

 

[ernestcarl]

Dirac room calibration using my target curve of preference, 19 measurements Spatial average.

View attachment 137487

Spectrogram at listening position before and after

View attachment 137492

SPL Sweep at listening position before and after

View attachment 137489

What's interesting to me is how the decay in your bass (a larger portion of it anyway) is quite a bit lower than that of everything above.

 

[ernestcarl]

Ok. Here is what I see on my mains with subs, with and without Dirac. This is what Dirac Live shows with 13 positions, and REW at main listening position with 1/12 smoothing (Blue = Before and Red = After). Does the SPL for the subs seem too high compared to Dirac measures, or are we saying that if we were to average 13 positions with REW we would measure levels similar to Dirac?

The red trace (post-correction?) in REW says you have an ~20 dB boost right around 30 Hz. Doesn't that seem rather excessive?

 

[Jbrunwa]

The red trace (post-correction?) in REW says you have an ~20 dB boost right around 30 Hz. Doesn't that seem rather excessive?

Yes. I know the default target curve is supposed to be a gradual downslope. I’m puzzled by how elevated the bass measures using REW vs prediction. This is why I was hoping that Dirac would give me a way to measure actual vs predicted, but the best I can do is to use REW, so I don’t know which to believe. Do I need to go in and artificially drop the bass in the Dirac filter, even though Dirac doesn‘t think it is necessary?

 

[ernestcarl]

Yes. I know the default target curve is supposed to be a gradual downslope. I’m puzzled by how elevated the bass measures using REW vs prediction. This is why I was hoping that Dirac would give me a way to measure actual vs predicted, but the best I can do is to use REW, so I don’t know which to believe. Do I need to go in and artificially drop the bass in the Dirac filter, even though Dirac doesn‘t think it is necessary?

The only thing I can think of is the calibration data of the microphone esp. around the bass is significantly off between REW and Dirac for some reason. Try listening to a sweep between a flattened bass and the more elevated one to see which sounds more even is to you perceptually.

 

[Martini]

I've been trying out the of Dirac's Standalone Mac beta. So far, I've had a few audio glitches that sound like system got hit by strong static pop. They always hit when I jump to a new song to sample. Anyway, NOT something I like to hear coming through my new Revels. Sound-wise, it seems to help with the bass region, but something is not quite right with the mids up. Maybe a little distortion from too much processing and female voices are better with it turned off. I'm not sure where to go from here. I'm certainly not ready/willing to drop $$ on a beta.

 

[abdo123]

@Jbrunwa Why you're not high-passing your mains?

 

[Kal Rubinson]

@Jbrunwa Why you're not high-passing your mains?

Yes. Especially with the sub running up to 200Hz. There could be a phase issue between sub and mains and/or an unfortunate microdomain at the MLP. I suggest reversing polarity on the sub and/or REW testing from a spot about 2' from the MLP. Just to gain insight.

 

[Jbrunwa]

@Jbrunwa Why you're not high-passing your mains?

Maybe I’m doing something wrong, but when the Dirac filter is applied in the speaker preset, it controls all cutoffs and filters, so any settings I make outside of that in the XMC-2 are ignored. The only change I can make is to adjust levels for the session or in the preset. At least that’s what I was told when I asked in an Emotiva forum.

 

[Kal Rubinson]

Maybe I’m doing something wrong, but when the Dirac filter is applied in the speaker preset, it controls all cutoffs and filters, so any settings I make outside of that in the XMC-2 are ignored. The only change I can make is to adjust levels for the session or in the preset. At least that’s what I was told when I asked in an Emotiva forum.

You need to create the crossover in Dirac.

 

[Jbrunwa]

You need to create the crossover in Dirac.

Well, I said I was new to this. I'm totally confused. I thought that Dirac does all the magic, detects and corrects phase, and decides the speaker cutoffs and filter slopes. So I need to add a control point to the mains to create a hi-pass filter and I need to calculate a slope that works, which it doesn't give you any help with, and pull down the mains starting at 50-80 Hz, and then I manually calculate a low-pass filter for the subs. How do I know what slope to use and where to set the crossover? I may as well just use the crossover options in the AVR then. I guess I will call Emotiva support and ask them for guidance. Thank you for your help. I apologize for taking up your time.

 

[abdo123]

Well, I said I was new to this. I'm totally confused. I thought that Dirac does all the magic, detects and corrects phase, and decides the speaker cutoffs and filter slopes. So I need to add a control point to the mains to create a hi-pass filter and I need to calculate a slope that works, which it doesn't give you any help with, and pull down the mains starting at 50-80 Hz, and then I manually calculate a low-pass filter for the subs. How do I know what slope to use and where to set the crossover? I may as well just use the crossover options in the AVR then. I guess I will call Emotiva support and ask them for guidance. I apologize for taking up your time.

what you're looking for is called Bass control.

 

[Aerith Gainsborough]

Regardless of the target curve, am I the only one who wishes that these products would allow users to actually measure the post correction result? I mean, you have to use other tools like REW, and there is no good way to use the same microphone positions.

While I understand what you feel I wonder: how many users would start to make a "good looking curve" instead of a "good sounding" one?
A good looking graph can sound worse.

Remeasuring at the same mic positions is very easy, if you mark them during the Dirac Calibration.
You could also use the moving mic measurement method before and after Dirac calibration for a nice average across the listening space.

I may as well just use the crossover options in the AVR then.

Yop, that's what I did too. AVR handles the actual crossover, Dirac does the rest.

 

[Jbrunwa]

what you're looking for is called Bass control.

Thanks.

what you're looking for is called Bass control.

Ah, I see now. Thanks. It's not available on my processor.

 

[Jbrunwa]

While I understand what you feel I wonder: how many users would start to make a "good looking curve" instead of a "good sounding" one?
A good looking graph can sound worse.

Remeasuring at the same mic positions is very easy, if you mark them during the Dirac Calibration.
You could also use the moving mic measurement method before and after Dirac calibration for a nice average across the listening space.


Yop, that's what I did too. AVR handles the actual crossover, Dirac does the rest.

EDIT: I followed up on the Emotiva forum about Dirac Live and crossovers. Dirac Live Bass Control is not available on Emotiva processors at this time. Dirac Live ignores the processor speaker size, crossover frequencies and slopes when you take measurements and generate export filters. However, the user can afterwards set speaker size, crossover frequencies and slopes and the processor uses these settings even when a Dirac filter is active. On my processor, speaker sizes are set to small, crossover frequency is 80 Hz, and slope is 24 dB/octave. These settings are not in effect when Dirac Live is run, but they are in effect when I run REW.

So I guess that it all goes back to the original problem I had. I have no idea how to compare the Dirac Live measurements to the REW measurements. I think that I will have to resort to trial and error with speaker levels, size, crossovers and measuring with REW post-Dirac.

 

[Jbrunwa]

I wanted to thank everyone who replied on this thread. Working off the REW measurements I have been able to improve the result by setting a control point in Dirac to bring down the sub around 30 Hz, reduce the sub level overall, and with the mains crossover at 80 Hz and 24 dB/octave slope. I can see now that Dirac Live won't be able measure the result because it doesn't do any bass control. So I have to do that external to Dirac using REW. I will still try to bring down the peak at 50 Hz a little tomorrow, but here is the result after the above adjustments. I'm pretty happy with the result. But I’m not happy with Dirac Live. In my mind it’s an incomplete product without bass management. Thats an extra charge and only available on a small number of processors. I will keep looking for better.