• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

REW measurements done. Please help interpret. Amazing? Horrible?

What I meant with point no. 2 is that this measurement here in yellow, i.e. with the DSP turned off:

View attachment 396685

looks different to this measurement in red (i.e. the "before" measurement which the Anthem is correcting). Notice the lack of the dip at 60Hz and lack of the bump between 10-15kHz, and the rest of the curves are subtly different:

View attachment 396686
What this means is that you are not comparing the same thing. There are two reasons why this may be so:

1. You are comparing a single point measurement vs. a multi-point averaged measurement,
2. You are using different microphones (Anthem ARC-1 for initial measurement vs. UMIK-1 for verification) and possibly making other mistakes with measurement as well. For example, vertical vs. horizontal orientation, using the mini-tripod and not a proper microphone boom stand, failing to move furniture out of the way, etc.

This also explains why the Anthem may have made that dip at 60Hz look worse after correction - it is optimising correction over a larger seating area.

There a few diagnostics you should consider if you want to move forward.

1. The first thing to do is find out whether the Anthem microphone performs the same as your UMIK-1. Do not assume that two calibrated measurement microphones will give you the same result. Condenser mics are fragile, too many knocks on the head and they will go out of calibration. If Anthem decided to cheap out on their measurement microphone, it may not even measure properly. Using a proper microphone boom stand, take a sweep with the Anthem. Then carefully replace it with the UMIK-1 and repeat the sweep from the exact same position. Compare the two sweeps.

2. Using the Anthem mic alone, perform "before and after" (i.e. DSP on and off) sweeps of the system from the same five points that you used to take the initial measurements with the Anthem. In REW, add all the "before" curves together (Trace Arithmetic - A + B, you will have to repeat the process). Do the same for all the "after" curves. This will give you a better idea of what the Anthem is doing since you are now comparing like with like.
I’ve done this before actually. Not this time but last year. The mics measure differently for sure. It’s frustrating. This is why I’m using REW in the first place. I trust the calibrated UMIK more than anthems mic. I even contacted anthem and they didn’t have much to say. So basically I’m trying to get REW happy.
 
I used both mics today static a MLP and here are the results. Fairly similar for the most part. I believe in the mic movement method and in the calibrated UMIK more than the anthem MIC so I'm tempted to focus on making REW happy. This is without correction I think. I'm going to start from scratch and take 5 new anthem measurements and EQ.

1728136235815.png
 
Just for your comparative reference and interest, let me share "my" Fq-SPL curve at my listening position and some typical REW wavelet measurements (just for example!) also at my listening position, all in my listening room acoustic environments with random furniture alignment and a few sound reflection planes/walls.
Ref. post #931 here;
Fig14_WS00007522 (5).JPG


During very early period of my multichannel audio project, I used REW wavelet analysis, for example (ref. #21);
WS000396.JPG


Please note that REW wavelet analysis has so many parameters (ref. #22);
WS000398.JPG


These posts would be also of your reference and interest, I assume, especially in terms of room acoustic modes;
- Identification of sound reflecting plane/wall by strong excitation of SP unit and room acoustics: #498

- Perfect (0.1 msec precision) time alignment of all the SP drivers greatly contributes to amazing disappearance of SPs, tightness and cleanliness of the sound, and superior 3D sound stage: #520


You can find photos and dimension of my listening room in this post;
- Not only the precision (0.1 msec level) time alignment over all the SP drivers but also SP facing directions and sound-deadening space behind the SPs plus behind our listening position would be critically important for effective (perfect?) disappearance of speakers: #687

My subjective comment/feeling shared here #502 would be also of your reference.
 
Last edited:
Ok can someone comment on my updated measurements? This is L+R with mic moving method with r-tings goal in the background. Please note the SPL axis, it's zoomed in quite close. Hopefully not as bad as it looks lol.
Screenshot 2024-10-19 162249.jpg
 
Just for my curiosity, I compared your updated above Fq-SPL curve with my SPL curve in identical (same) X(Fq) and Y(SPL) scale/axis;
WS00007868.JPG
 
Last edited:
Mic measurement of Fq-SPL is representing only one aspect of our audio system and room acoustics, and mic measurement is not representing our ears+brain subjective listening sensations. Our brain has wonderful capabilities of room-mode compensation and Fq-SPL smoothing.

Furthermore, the measurement method of yours (moving mic with sine sweep?) is not the same as my method (recorded rich-white-noise FFT averaging), and hence the two SPL curves cannot be discussed/compared objectively.

Your listening sensations would also greatly dependent on your personal preferences and various room modes of your listening acoustic environments.

So, if you feel your present sound at your listening position would be reasonably acceptable for you, I would like recommend you to just keep it as it is now.


Nevertheless, if we would dare to discuss just based on the simple comparison of the two curves, I think you may test/evaluate some more EQs in the important 100 Hz to 1 kHz zone to make the SPL curve more smooth resembling the target purple curve...

Please note again, however, that Fq-SPL is only one aspect of the acoustic characteristics in your listening environment; you have many other important factors like time-alignment, reflection/reverberation, standing waves, furniture alignments, etc.

By the way, I highly recommend you to prepare and use your own (preferable) consistent "Audio Sampler/Reference Music Playlist" consists of various (your preferable) music genres, just like my "Reference Music Playlist" I shared in my thread here.
 
Last edited:
The reason I am posting the SPL is because I am happy with the rest of things I think, that's all that's left. The EQ makes sense and I wish Anthem ARC did it more. Obviously more is required.
 
Ok can someone comment on my updated measurements? This is L+R with mic moving method with r-tings goal in the background. Please note the SPL axis, it's zoomed in quite close. Hopefully not as bad as it looks lol. View attachment 400102

1. A +6dB bass shelf is a lot of bass. If you want a bass shelf, +3dB would sound more realistic. That said, it's your preference. You might like it.
2. In every measurement you posted, I see the same 12kHz peak. This will be a speaker issue. Sometimes speakers will have a peak to compensate for an off-axis dip so that the overall listening window is smooth. I don't know if that is the case without looking at a spinorama. Or you could rotate your speakers 30deg off axis and repeat the measurement to be sure. If it is not compensating for anything, you can consider removing it.
3. That upper bass peak of about 150Hz is too big. It is 10dB above the 1kHz reference. It would definitely be audible.
4. I cross referenced your current curve with your the older measurements you posted. I see that this 150Hz peak is new. The dip that was apparent at 60Hz has now disappeared. What did you do?
 
1. A +6dB bass shelf is a lot of bass. If you want a bass shelf, +3dB would sound more realistic. That said, it's your preference. You might like it.
2. In every measurement you posted, I see the same 12kHz peak. This will be a speaker issue. Sometimes speakers will have a peak to compensate for an off-axis dip so that the overall listening window is smooth. I don't know if that is the case without looking at a spinorama. Or you could rotate your speakers 30deg off axis and repeat the measurement to be sure. If it is not compensating for anything, you can consider removing it.
3. That upper bass peak of about 150Hz is too big. It is 10dB above the 1kHz reference. It would definitely be audible.
4. I cross referenced your current curve with your the older measurements you posted. I see that this 150Hz peak is new. The dip that was apparent at 60Hz has now disappeared. What did you do?
Yes it is a big shelf. Part of the problem was me trying to bring up the low bass to a higher level, which of course brought up the rest because I can't fiddle with frequencies in ARC. I will think about this.

That 150hz peak is huge for sure. I might add additional EQ software or something, I'm not sure.

The 60hz dip is gone because I moved the crossover up to 90hz. These were a LR problem. I did not realize that the 150hz peak is new, which is interesting. I don't know what caused this. I did do new measurements with ARC so perhaps something changed there.
 
OK, it's a nice improvement :) Not perfect but it will get better if you keep working at it. Well done!
Yes but what does it mean to keep working at it? That's kind of the problem. I ran Anthem ARC and played around with it but I've reached the limits of what it can do. Should I disable ARC and use another EQ? Should I enable ARC and use another EQ on top of it? I kind of like the second idea but I dunno.
 
I can tell you with 100% certainty that DSP will be able to fix the problems we observed. In general, bad outcomes following DSP may be due to either:

- inadequate DSP software or hardware. Without knowing the capabilities of Anthem ARC I can't tell for sure. You will need to do some experiments. Suggested experiment: Set up your mic on a mic boom tripod and measure with Anthem ARC. Generate a correction from it. Without moving the mic, use REW a measurement with and without the Anthem corrections. Compare the "before" of the Anthem with the "before" of REW. Then compare Anthem's predicted outcome with the actual outcome measured with REW.

- user error: (1) improper measurement technique. Use a mic with a boom tripod (ALWAYS!!). Point the mic at the front speakers on axis from the listening position. (2) improper use of software / inappropriate corrections.

I don't own an Anthem. So I don't know the capabilities of the software/hardware. You'll need to figure that one out.
 
I agree with @Keith_W!

And, if possible at your (OP @Snoochers') side, I highly recommend you to measure Fq-SPL at various/each-of-the "stages", i.e. in most upstream digital domain, in analog line-level domain, in SP-high-level amp out, and of course in room air sound.

If you would be interested, please visit my posts under the below spoiler cover.
- Frequency response measurements by "cumulative white noise averaging": #392, #404, especially the end portion of #297(remote thread) by Dr. Floyd Toole, #315(remote thread) by Dr. Floyd Toole, #125(remote thread)

- Where in my multichannel multi-driver (multi-way) multi-amplifier stereo system should I measure/check frequency (Fq) Responses? #393

- Frequency (Fq) responses in the completed system measured by using “cumulative white noise averaging method” under the present standard crossover configurations and relative gains_Part-1_Fq Responses in EKIO’s digital output level: #394

- Frequency (Fq) responses in the completed system measured by using “cumulative white noise averaging method” under the present standard crossover configurations and relative gains_Part-2_Fq Responses in DAC8PRO’s analog output level: #396

- Frequency (Fq) responses in the completed system measured by using “cumulative white noise averaging method” under the present standard crossover configurations and relative gains_Part-3_Fq Responses in amplifiers’ SP output level before protection capacitors: #401

- Frequency (Fq) responses in the completed system measured by using “cumulative white noise averaging method” under the present standard crossover configurations and relative gains_Part-4_Fq Responses in amplifiers’ SP output level after protection capacitors: #402

- Frequency (Fq) responses in the completed system measured by using “cumulative white noise averaging method” under the present standard crossover configurations and relative gains_Part-5_Fq Responses in actual SP room sound at listening position using one measurement microphone: #403

- Frequency (Fq) responses in the completed system measured by using “cumulative white noise averaging method” under the present standard crossover configurations and relative gains_Part-6_Summary, discussions, and a little step forward: #404, #405-#409
 
Last edited:
I can tell you with 100% certainty that DSP will be able to fix the problems we observed. In general, bad outcomes following DSP may be due to either:

- inadequate DSP software or hardware. Without knowing the capabilities of Anthem ARC I can't tell for sure. You will need to do some experiments. Suggested experiment: Set up your mic on a mic boom tripod and measure with Anthem ARC. Generate a correction from it. Without moving the mic, use REW a measurement with and without the Anthem corrections. Compare the "before" of the Anthem with the "before" of REW. Then compare Anthem's predicted outcome with the actual outcome measured with REW.

- user error: (1) improper measurement technique. Use a mic with a boom tripod (ALWAYS!!). Point the mic at the front speakers on axis from the listening position. (2) improper use of software / inappropriate corrections.

I don't own an Anthem. So I don't know the capabilities of the software/hardware. You'll need to figure that one out.
I did the anthem ARC to the absolute letter of their suggestions. Five points on the provided stand in an X pattern. Is it ok to add EQ on top of EQ?
 
Try this:

A. Referring to the blue line, bring the average in that area down to the blue line.

1728136235815.png


B. Add the following "tape head bump" PEQs.
  • 69Hz +2.5dB Q=1.00
  • 138Hz -2.2dB Q=1.00

Listen & see if you like the result...
 
Try this:

A. Referring to the blue line, bring the average in that area down to the blue line.

View attachment 400291

B. Add the following "tape head bump" PEQs.
  • 69Hz +2.5dB Q=1.00
  • 138Hz -2.2dB Q=1.00

Listen & see if you like the result...
I don’t know what you’re talking about. Is this something in ARC? I’m not familiar with that setting
 
I did the anthem ARC to the absolute letter of their suggestions. Five points on the provided stand in an X pattern. Is it ok to add EQ on top of EQ?

Yes it is OK to add EQ on top of EQ.

I suspect I know why you have that funny bump at 12kHz. It is because you are using this:

1729433846376.png


Measurements need to be taken properly. There needs to be adequate clearance from reflective surfaces because those will create spurious bumps in your FR curve do not normally exist.

At this point I have to apologise because my ability to help you is limited because I don't own an Anthem, and I don't know how their software works. I did a bit of sleuthing for you in the earlier graphs you posted. The reason that 12kHz peak exists and your Anthem does not correct it is because it does not know it is there (see the "before" measurements for your Anthem that I cut and pasted in this post).

Read this very carefully: the key to understand why something is happening is to compare before and after whilst keeping all variables (e.g. microphone position, speaker position, etc) exactly the same.
 
Yes it is OK to add EQ on top of EQ.

I suspect I know why you have that funny bump at 12kHz. It is because you are using this:

View attachment 400302

Measurements need to be taken properly. There needs to be adequate clearance from reflective surfaces because those will create spurious bumps in your FR curve do not normally exist.

At this point I have to apologise because my ability to help you is limited because I don't own an Anthem, and I don't know how their software works. I did a bit of sleuthing for you in the earlier graphs you posted. The reason that 12kHz peak exists and your Anthem does not correct it is because it does not know it is there (see the "before" measurements for your Anthem that I cut and pasted in this post).

Read this very carefully: the key to understand why something is happening is to compare before and after whilst keeping all variables (e.g. microphone position, speaker position, etc) exactly the same.
This is all sensible but the problem is I can’t keep things exactly the same because I’m using two different measurements software and two different microphones. But I will keep investigating.
 
Read this very carefully: the key to understand why something is happening is to compare before and after whilst keeping all variables (e.g. microphone position, speaker position, etc) exactly the same.

Again, fully agree with this important point.

In any technical/scientific study/test, it is critical/indispensable that you (we) do not change multiple parameters at once; change only single parameter, and then compare "before and after".

If you change e.g. two parameters at once, the pros and cons would happen at once to give no improvement or even worse effect or overlapped improvements; in this situation you cannot identify/assess the pros/cons of each of the two parameter changes.
 
Back
Top Bottom