REW Beta Release Changes in REW V5.20 beta 8

[Breeman]

I just ran a quick check with a UR22 mkII and my desktop speakers and got figures within about 20 mm of the physical distance (which was 680 mm), but my IR looks a lot cleaner:

View attachment 13612

It looks like the peaks of your measured IR occur some while after the response starts, which is the likely cause of the higher delay figure (assuming nothing in the path after the UR22 is adding delay). Should look into why there is so much going on before the peak in your measurements. Presume you are measuring a single speaker.

Thanks for verifying the functionality.
I forgot to mention that I was testing inside the car cabin hence the "contaminated" impulse response. The UR22mkii is directly connected to the amplifiers so there is nothing that should causing the delays. The car cabin is quiter than in the house so not quite sure what could be causing the noise before the main impulse peak. I seem to recall from reading the literature that certain reflections could; when combined with the direct response, be larger than the direct signal inside car cabins. Could these and other multiple reflections inside the cabin be contributing to the difficulty in picking up the actual impulse peak?

 

[John Mulcahy]

A car cabin is a difficult measuring environment with a lot of close reflections. If you post an mdat with some measurements I can see if anything looks odd.

 

[Gregwor]

Hadn't realised you were on macOS Greg, sorry. You should find the message goes away with the gain set to 20 dB. The good news is that doesn't affect the sensitivity factor as REW compensates for the volume setting. The bad news is the macOS compensation is wrong and I haven't had any luck getting the info I need to correct it, per this thread, so you could come to the rescue! From the post on that thread I know 0.25 is 5 dB, and from your post 1.0 is 20 dB, if I can get a few more combinations of volume figure and gain I can correct the compensation for the next beta release. I need the gain in dB when volume is zero and ideally for a few other settings. All this will affect is the SPL figure when you make a measurement, it doesn't affect the shape of the measurement, so the results are good regardless.

Sorry this took so long. I've been swamped.

Using the check levels feature in the preferences window, I tested how the Ref In was affected by the OSX audio/midi setup gain adjustment that goes from 0 to 20.

So as you can see, for the first few increments I noticed no change by increasing the gain by 0.5dB. It's the same whether I have it at 3 or 3.5. I checked the 0.5dB increases all the way up to the max 20dB in the OSX audio/midi setup window and the 0.5dB increases never changed the Ref In reading. So, I stopped documenting those after 3.5. For the Ref In values recorded, they were jumping around, fluctuating ~ 0.8dB so I documented the average.

Note: The microphone was positioned where my Galaxy Audio CM-130 SPL meter read 80dBC.


GAIN Ref In dbFS
0 -55.7
0.5 -55.7
1 -54.2
1.5 -54.2
2 -52.8
2.5 -52.8
3 -51.4
3.5 -51.4
4 -50
5 -48.6
6 -47.3
7 -45.2
8 -43.8
9 -42.5
10 -41
11 -39.5
12 -38.1
13 -36.8
14 -35.5
15 -33.3
16 -31.8
17 -30.4
18 -29
19 -27.5
20 -26.2

Hopefully these are the numbers you need! If not, please let me know how you'd like me to re-measure!

Greg

 

[John Mulcahy]

Sorry this took so long. I've been swamped.

No problem. The figures I'm after are from the Audio Midi Setup dialog, the ones highlighted in yellow and green below. The yellow is the volume slider position in the range 0 -> 1, the green the corresponding mic gain figure. A key value I'm missing is the gain figure when the slider is all the way to the left, when the yellow figure should read 0.0. I made a guess that it would show -10 dB when that yellow figure is zero, if it does then all good. Otherwise it would be handy to know the gain figures for a few other slider positions.

 

[Breeman]

A car cabin is a difficult measuring environment with a lot of close reflections. If you post an mdat with some measurements I can see if anything looks odd.

Thanks John,
Here is the link to the same mdat file I took the screenshots from; http://www.filedropper.com/frseattimedelaytests Let me know should you need other measurements.

 

[John Mulcahy]

Are you sure there is no processing going on and no other speakers playing besides the one being measured?

 

[Breeman]

Are you sure there is no processing going on and no other speakers playing besides the one being measured?

The measurements were done before I had the minidsp C-DSP 8x12 installed; the RCA cables going to the amplifier would be unplugged from the radio deck and I would physical connect the UR22mkii output to one amplifier input channel at a time.

 

[John Mulcahy]

Not sure what would cause the appearance of the impulse responses then, but I haven't made in-car measurements.

 

[Ultrasonic]

I can't remember if this was the same in the older version, but I've noticed the following with the current beta. I often change the colours of profiles so that ones I'm directly comparing show up better against each other, but I've spotted that if I save data with the colours changed like this, when I reload it they are different.

I've also had some issues with using an acoustic timing reference that I didn't in the old version. The beta encourages the use of a louder reference (to the point of it being slightly uncomfortable to hear) but even with this it sometimes doesn't work properly. What can happen is that the timing reference seems to arrive before the software is ready, and so the measurement fails as it says it's still waiting for the reference. This never happened to me with the previous version.

 

[John Mulcahy]

I can't remember if this was the same in the older version, but I've noticed the following with the current beta. I often change the colours of profiles so that ones I'm directly comparing show up better against each other, but I've spotted that if I save data with the colours changed like this, when I reload it they are different.

There is a View preference for that.

I've also had some issues with using an acoustic timing reference that I didn't in the old version. The beta encourages the use of a louder reference (to the point of it being slightly uncomfortable to hear) but even with this it sometimes doesn't work properly. What can happen is that the timing reference seems to arrive before the software is ready, and so the measurement fails as it says it's still waiting for the reference. This never happened to me with the previous version.

There is a bug in the timing reference detection that has been fixed for the next beta.

 

[Ultrasonic]

There is a View preference for that.

Ah, good. It might be worth making this be ticked by default, since I'd have thought generally people would want this to be the case?

 

[John Mulcahy]

That can lead to a lot of repeated trace colours if multiple measurement sets are loaded. An alternative is to edit the default colours in the View preferences.

 

[Ultrasonic]

That can lead to a lot of repeated trace colours if multiple measurement sets are loaded. An alternative is to edit the default colours in the View preferences.

For my own use I'd want the colours saved specifically to avoid lots of repeated colours but I realise this will come down to how many measurements people typically save in each mdat file. I tend to save lots together and change the colours of the set to be able to distinguish adjacent curves, and want these colours preserved when I save the file. I'm guessing you're though coming from the perspective of people saving single measurements per mdat file, or just a few.

With this in mind I can see how having this as a selectable option is a good feature . I'll just have to remember to tick it later.

 

[Gregwor]

No problem. The figures I'm after are from the Audio Midi Setup dialog, the ones highlighted in yellow and green below. The yellow is the volume slider position in the range 0 -> 1, the green the corresponding mic gain figure. A key value I'm missing is the gain figure when the slider is all the way to the left, when the yellow figure should read 0.0. I made a guess that it would show -10 dB when that yellow figure is zero, if it does then all good. Otherwise it would be handy to know the gain figures for a few other slider positions.
View attachment 13631

Here you go John!

Thanks again!

Greg

 

[John Mulcahy]

Not what I expected but very helpful Greg, thanks!

 

[Ultrasonic]

One minor issue I spotted was that for measurements I couldn't change the Max SPL limit from 100 dB, using either the arrows or clicking on the number.

This will be a personal preference but one thing I would like changed is to stop any of the windows that open being locked in the foreground. Or to just make it an option to tick if you'd like this to happen or not. Having windows forced to stay in the foreground is annoying when switching between applications, most commonly in my case switching between REW and the miniDSP software to change settings for what is being measured.

(I've now switched back to using 5.19 due to the timing reference bug.)

 

[John Mulcahy]

One minor issue I spotted was that for measurements I couldn't change the Max SPL limit from 100 dB, using either the arrows or clicking on the number.

Thanks, that's fixed for the next beta.

This will be a personal preference but one thing I would like changed is to stop any of the windows that open being locked in the foreground. Or to just make it an option to tick if you'd like this to happen or not.

That's been on the ToDo list for quite a while, I've added View preferences for keeping the SPL meter, VU meters and signal generator on top of other windows.

 

[Ultrasonic]

That's been on the ToDo list for quite a while, I've added View preferences for keeping the SPL meter, VU meters and signal generator on top of other windows.

Any chance of adding this for the measurement window too? When making a series of measurements I have to keep closing this to be able to see the miniDSP window I need to change the settings.

 

[John Mulcahy]

Any chance of adding this for the measurement window too? When making a series of measurements I have to keep closing this to be able to see the miniDSP window I need to change the settings.

Do you mean the Measure dialog? That needs to be a modal dialog, but it is only open for the duration of a measurement and closes itself when the measurement completes. What settings are you changing while the dialog is open?

 

[Ultrasonic]

Do you mean the Measure dialog? That needs to be a modal dialog, but it is only open for the duration of a measurement and closes itself when the measurement completes. What settings are you changing while the dialog is open?

The window that appears when you click on the Measure icon, that says 'Make a measurement' at the top left.

I'd forgotten it closed at the end of the measurement but I have often still ended up wanted to make changes while it's up, or check something. Principally this is changes to signal routing to have the right combination of speaker and subwoofer, and levels.

It's a personal thing, but essentially I don't like any window in any application to ever force itself to stay in front - I like to be in control . I can't think of any situation where I've found the opposite useful. I appreciate others may take the opposite view .

 

[John Mulcahy]

It is a modal dialog, preventing interaction with other application windows while it is open. That is because other interactions could cause invalid measurements. The Measure dialog needs the always on top setting or it can get trapped behind other windows where the user can't access it, locking the application until it can be brought to the front - that isn't always possible, depending on the OS and the way Java interacts with the OS window mechanisms.

 

[Ultrasonic]

The Measure dialog needs the always on top setting or it can get trapped behind other windows where the user can't access it

I would have thought that it would always be possible to get to it via Alt-Tab?

I'll accept you have a good reasons for forcing the Measure window to stay at the front though.

 

[AudiocRaver]

My 2 cents, it makes perfect sense to me just the way it is. The window stays up because the operation has to be completed before it is meaningful to move on.

Most of what can be changed from that screen is also on the first Preferences panel. John has made a lot of the commonly changed REW variables accessible from almost anywhere, which is convenient, but makes easy to forget where you are.

Just my way of thinking about it.