Question on time and level aligning my 5.0 System

[JoachimStrobel]

Hello,
since a week I own a NanoAvr HDA and REW (and a Umik). This is a super package and REW a unbelievable professional software.
Step number one is time and level alignment of my 5 loudspeakers.
Two questions:
In EQ I can set a target level. If I set all five channels EQs to 75 dB, do I then still need to level adjust the speakers with the SPL module or is this then taken care off?
I have set up the timing signal in the measurement task to be on the Centre speaker. When I open the impulse graph, the Centre speaker’s measurement is at -3 ms! The left speaker is at -4ms, but the right speaker is at -7ms! The microphone is perfectly centered. The delay labels in the measurement tabs say the same. What could have gotten wrong? Could this be a non uniform delay introduced by the setup:
PC-HDMI(ASIO) - HDMI 5:1 switch - Oppo103 - NanoAvr-Psp1500-Canton RCL Controller -Hca1200

Many thanks for any help.

 

[John Mulcahy]

The EQ target level is to help find the underlying level of the measurement so that filters don't mistakenly get used as level controls. It doesn't perform any kind of level adjustment on your system.

For your time alignment question it would be better to post an mdat file with the measurements. If you aren't already using the latest V5.20 beta version it is worth upgrading to that, there have been a few changes in the timing calculations.

 

[JoachimStrobel]

John,
Thanks for your reply.
I tried upgrading to both the 5.20 release 12 and 13. I got release 12 to start once, then never, and release 13 never started after installation. Re-installing 5.19 helped and this release works flawlessly. I have a maintained Win10-32 system.
I begin to realize that the timing sweep is 2-20khz (?) while my measuring sweep is 15hz-20khz and that might cause inconsistencies,

 

[John Mulcahy]

This note from the 32-bit installer download entry may be relevant. Wouldn't expect this to affect Win10 but perhaps the 32-bit Win10 behaves differently:

When installing REW on Windows XP, Vista, 7, 8 or 8.1 you may encounter a somewhat cryptic error message: "The program can't start because api-ms-win-core-timezone-l1-1-0.dll is missing from your computer. Try reinstalling the program to fix this problem.". This is caused by the Java runtime using components from the Windows Universal C Runtime which are not present on older Windows installations. To fix it see this Microsoft knowledge base article, KB2999226 or for 32-bit Windows XP use the Visual C++ Redistributable Runtimes AIO Repack v19 2019-04-24.

 

[JoachimStrobel]

John,
I did set the target level for one speaker to 30 dB, and left the other at 75db in EQ. The result is, that the speaker with a target of 30db is if course not as loud as the other. Hence, after I leveled my system, it seems that I have to set a constant target level for all speaker in EQ. I believe that the target level should be lower than my lowest frequency ditch. In order for the Preamp not to run out of volume control, that could mean that I need to level my system first a bit above 75db. Is that thinking correct?

 

[John Mulcahy]

The target level should run through the middle of the response. Use EQ to tackle peaks in the response.

 

[JoachimStrobel]

John,

sorry for being slow with this thread, but summer seems to be the wrong time to start this,,,,
I have made delay measurements with Version 5.19 (one day I will tackle this dll problem for 5.20...) and have limited the sweep to 2-20Khz. This gives decent results now, but they are still different to my tape measure. There is some variation between using 128k and 1M sweeps, These Problems are probably addressed in the 5.20 releases. I tabulated my results below. I have not included the results from a 15hz-20Khz sweep, they are just horrible. I did increase the volume so that the 2Khz starts at.30db headroom.

I do not understand the choice of LEVEL during the EQ process. I though one should avoid boosting amplitude but rather reduce them. Hence it seems wise to use a good lower limit. For me this is 65 dB (system leveled to 75db) where the high frequency (>12Khz) reduces in amplitude slowly. If I use 75 db, that high amplitude dip does not get corrected. I could accept this a being part of a room curve, but I want to equalize for a screen-down position too, where, sadly, my center speakers are partly covered. Using a 65db for all, gets this job done nicely.

I have done a time and level alignment before Eqing. I assume that, after I activated the filters in my miniDSP I need to level my system again? And time align too?

	Distance			Measured	2-20kHz
			calc		Center ref		SL ref			FINAL
	ft	min ft	ms		256k	min	128k	256 k	1m	min 128k
L	12​	5.5​	0.16​		2.65​	10.23​	10.21​	10.04​	9.73​	10.33​
C	10​	3.5​	3.11​		-0.11​	7.47​	7.39​	7.27​	6.87​	7.51​
R	12​	5.5​	4.89​		2.63​	10.21​	10.13​	10.08​	9.63​	10.25​
SL	6.5​	0​	0.00​		-7.58​	0.00​	-0.12​	-0.16​	-0.61​	0.00​
SR	14.8​	8.25​	7.33​		5.75​	13.33​	13.24​	13.11​	12.75​	13.36​

 

[John Mulcahy]

On your level question: EQ is good at countering the gain that room mode resonances add. It is not good at filling dips - they are usually very sensitive to location, so correcting a dip at one position can create a new peak from the correction filter at other positions, even a very short distance away. Level should usually be set so that it lies roughly where the level would be without the peaks and dips of the room.

 

[JoachimStrobel]

John,
I did install Windows 10 SDK (10.0.18362.0) and Visual Studio Community 2017, rebooted a couple of times - but 5.20R15 (any R) will not run on my WIn10-32bit system. I am happy that version 5.19 installs and runs OK every time. A shame as I still do not understand why the REW delay are so different to the manually measured ones. I checked them again - the tape measure does not lie. May be my air has a strange composition....
I have read that I could check the delay by checking for +6dB for any combined channel in RTA, but I tried that but got no precise results.

 

[John Mulcahy]

What happens when you try V5.20? Does it install but fail to launch, fail to install, something else? Are there any error messages or error logs?

 

[JoachimStrobel]

John,
it installs OK. I always keep my old setup files when re-installing. But then it never launches. The HD is busy for 20 sec - but then nothing. I do still have an interface card to an MAudio 1010 mounted in a PCI slot. That did cause me some trouble installing ASIO drivers (I belive), so that could casue it. I will remove it and clean the system on a rainy day and try again...

 

[John Mulcahy]

After trying to launch 5.20 it is worth looking to see if the REW log file has been started and captured anything (in the REW folder of your user directory). If you don't even get the splash screen it probably hasn't got that far though. What Java version(s) do you have installed?

 

[JoachimStrobel]

So, I re-installed the latest Jave (from April 2019), removed my 1010-Pci card, re-installed the Asio drivers:
5.20R15 would nut run when set to 1.5 Gb but started after installing with default 1Gb. But Umik was not available in Asio - red cross. I tried disabeling system sounds and removed exclusivity to the mic, cycled the USB port and reloaded the Asio panel a couple of times - did not help.
Reinstalled 5.19: Umik is back. When trying to do a check within the preference window, I get a message that Asio did reset and no sounds playing, even after re-loading ASIO etc.
But when playing the sound generator and using Level display all works fine. measurements are fine.
Hope there is not more to come...

 

[John Mulcahy]

See this thread on the UMIK issue.

 

[JoachimStrobel]

Thanks, I did not seaa THAT UMIK thread. But I only have one device, no Soundcard, so Windows gives me no choice. I am working ahead with REW 5.19, am reading Toole´s book to understand half of what I am doing and enjoy the great software.
May be one more: Is this workflow OK:

- Level speaker without filters with Loudspeaker pink noic and SPL logger
- Record sweeps
- Design EQ, change level for the best result (going even down to 65 db).
- Install filters (NANOAVR)
- Re-level loudspeaker

 

[John Mulcahy]

Yes, that looks fine. I have finally tracked down the problem with UMIK not available and fixed it for the next build.

 

[JoachimStrobel]

Btw,
The first editions of Toole’s book can be found here:

https://we.riseup.net/assets/443799/Sound+Reproduction+The+Acoustics+and+Psychoacoustics+of+Loudspeakers+and+Rooms+Floyd+Toole.pdf

Additions to the third edition can be found here:

https://routledgetextbooks.com/textbooks/9781138921368/

Marvelous reading, makes REW even more enjoyable.