Really impressive: the result and the effort to get it!
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What do you suggest taking measurements by REW with a MacBoo/ laptop and USB mic?
- Connecting the laptop to the DAC via USB and playing the sweep signal
- Creating a sweep file with REW to be loaded on the server/streamer hard-dish then playing the file from there
I don’t use the preamp in my system, so I adjust the volume from the DAC itself.
Levels
The test signal defaults to an RMS Level of -12 dBFS but a few tutorials mentioned that -20 dBFS is enough.
REW guide suggests a 75dB level volume from the system’s speaker at the listening position (as measured by the USB UMIK and shown on the SPL meter tool of REW). Are you saying that 83 dB is better?
Taking measurements from different speakers separately
Selecting R and L in the output settings of REW window means that the signal will be automatically played from R or L speaker?
Do I need to correspondingly select the same R and L option on the input setting every time I take a measurement?
TIA
My take:
-connect laptop to dac. Far easier
-use -20dB
-75 to 80dB would be fine. You want about 40 to 50dB of headroom from ambient noise. Don’t push it to risk your tweeters.
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Very nice! Thanks for sharing. I, myself, would not have tolerated the 30s of sitting still…
You use a different measuring method, that makes it hard to compare. Should I dial this target curve to my eq, it would sound awfully bright and thin, lacking bass. But again, this is the method.
Out of curiosity, what is the output of the software? A convolution file to be loaded up in roon?
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Thanks, my room is quite silent (around 26 dB) so I can set pretty low with volume level considering 40-50 dB headroom!
Go with 75. If you want, post your frequency response and spectrogram charts and we can help you with the first interpretation.
In frequency response chart, set smoothing to 1/12, and the X-axis on +40dB. It makes everything easier to read.
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26db background noise is a sound laboratory! You should be proud of your accomplishment.No wonder the small equipment noises were driving you crazy.
My “normal” living / listening space is around 50 db.
All of that headroom will make the software much easier to use as there is less unknown noise being generated in the background that will show up in the recording.
Yes as mentioned use 75-80 db level when testing one speaker at a time. You automatically pick up 3db or 6db (I have forgotten) when both speakers are playing (double sound pressure from double sources)
Yes switch the default output to L tests left speaker as one file and select “R” right as another file.
That way you can see the differences in level from L to R and adjust as needed.
This will show any output differences between the two speakers at the microphone position.
Once you get a couple of files generated you will start to get a feel for the software.
The input can be left alone (I think) as it is a mono signal and is generated and automatically going to both speakers id L+R is selected.
Use timing reference signal. It’s ok to leave it on the right channel
When you “take a measurement” tab is opened the lower left corner box will show levels and advise if the setting is too low. That is when you would adjust the “sweep level” (-12, -16, -20, etc.) Normally -12db is good but as mentioned you can try -20 and see.
One other thing to note is to carefully name your files and add plenty of notes to the file info on the graph page. Some of this is slowly coming back to me but I still haven’t found my notes
Also try to not be in the sound field when making the recordings as your body will affect the recorded signal. You can set a delay on the measure page here:
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Also set the scaling so the graph is in 5db increments.
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Semantics. It didn’t boost the highs merely shaved off the lows which flattened the curve. Much better to take away than to boost. I hope I see my ORC upgrade email soon.
Is this with subs on. Its nice to see a curve with some low end grunt.
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Luca, I’m late to the responses but everything you’ve gotten from @jvvita and @Baldy is right on target. One additional recommendation - do not use sweep lengths of longer than the default 256K. That is sufficient for what you need to do. It’s tempting to use longer sweep lengths because it will result in a better S/N ratio for the analysis, but it is completely unnecessary for standard room measurements, and can potentially overheat the tweeters!
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Correct. I forgot about that setting.
Fortunately most of the defaults are safe and correct for most situations.
Thanks
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Thank you @jvvita @Baldy and @tony22 you are so kind guys!
I feel like I’m back in school but it’s fun! Please be lenient with me, even if you find my questions silly and I make trivial mistakes - I’m a bit embarrassed, I’m definitely not a tech guy!
Tonight I will test the MacBook - DAC connection to make sure it works correctly, then over the weekend I will take the first measurements and I will be happy to share them with you.
As for my room, yes, it’s quite dampened: you can see my renovation step by step in these forum posts:
and a more recent pic here
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good luck! you wont regret the effort.
As you often say in Italy: forza e coraggio!
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Have fun and remember no matter what you do you cant break anything.
You will be head spun for sure but when you get that way just close the lid on the laptop and play some music. 
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I’m too tired to take more measurements but I’ve done a few tests, just to understand how it works.
L+R with SUBs
L+R without SUBs
L+R vs L+R with SUBs
L vs L with SUB
R vs R with SUB
L vs R
RT60
L+R Waterfall
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This was done with my Bacch4Mac processor. It took the measurements and made the room corrections itself. No external device needed. The room correction can be enabled and disabled with a mouse click. It can also be fine tuned.
I am happy you pointed this out. Thank you.
The result if using room correction is a 7.7dB drop in output. Turn room correction off and there is a 7.7dB jump in gain which makes instant comparisons a bit difficult.
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Understood. But where does it reside? On a Mac mini? And then you play from the mini to your dac?
Looks to me like you are already done. It doesn’t get much better than that.
Excellent planning has paid off handsomely for you.
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