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Monstieur

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Pardon me if this isn't exactly on-topic, but is there any other system-wide EQ for Windows that will work with ASIO? One of my use cases is one I have not seen mentioned yet, which is playing VST instruments via a MIDI controller. Only ASIO has low enough latency for me, but I would love to have global EQ for my HD650s as I bounce between different audio production and editing apps. Using DirectSound for this makes playing my virtual piano feel like playing organ in a large gothic cathedral.
You can insert an EQ plugin in the VST chain which is separate from Equalizer APO in WASAPI. Both ASIO and WASAPI can be used in parallel if your interface supports it.
 

voltronic

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You can insert an EQ plugin in the VST chain which is separate from Equalizer APO in WASAPI. Both ASIO and WASAPI can be used in parallel if your interface supports it.

That's interesting, but I don't know how using them in parallel would help since Equalizer APO would also be bypassed by WASAPI.

I suppose I could insert an EQ with the appropriate correction on the master bus of my DAW where I host my VST instruments, with the DAW set to ASIO output. Then the rest of my audio apps that don't need the very low latency can output to Equalizer APO.
 

Monstieur

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That's interesting, but I don't know how using them in parallel would help since Equalizer APO would also be bypassed by WASAPI.

I suppose I could insert an EQ with the appropriate correction on the master bus of my DAW where I host my VST instruments, with the DAW set to ASIO output. Then the rest of my audio apps that don't need the very low latency can output to Equalizer APO.
Equalizer APO would be bypassed only in WASAPI exclusive mode. There is no APO-based EQ solution for exclusive mode. Most desktop applications would use shared mode anyway where Equalizer APO would work.

The interface would mix the WASAPI shared mode or exclusive mode streams with ASIO if it supports simultaneous use of both APIs. The EQ for ASIO would be applied in the VST plugin chain.

If your interface support ASIO multi-client, you can use a combination of loopback and spare I/O to route the output mix through another VST host like Cantabile with an EQ plugin. You can also use this technique to apply EQ to WASAPI exclusive mode.
 

voltronic

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Equalizer APO would be bypassed only in WASAPI exclusive mode. There is no EQ solution for exclusive mode. Most desktop applications would use shared mode anyway where Equalizer APO would work.

The interface would mix the WASAPI shared mode or exclusive mode streams with ASIO if it supports simultaneous use of both APIs.
OK, I got you now. I will investigate further.
 

Jose Hidalgo

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Monstieur

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That’s a good workaround as well. Not sure of the impact on latency and buffers through.
 

Atanasi

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That is a very interesting thread; thank you. Although as @Monstieur says, the latency is a concern.

Just for reference, if DAC sample buffer on my MOTU (in ASIO mode) is above 1024 samples, then the latency unusable for live playback.
I think ASIO input to Voicemeeter adds one cycle of latency, so 256 becomes 512, for example.
 

artburda

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I ran some tests and somehow Windows 8.1 is applying the CAudioLimiter no matter what I do. I installed PEACE, "Use original APO" is greyed out and I can lower the volume in PEACE or in the Windows Volume Mixer and there is always an additional -0.12dB in REW when I measure the digital 1kHz signal in loopback mode. What could be the cause?
1621632805702.png
 
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daftcombo

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Filter Induced Digital Peaking
Perhaps less well known is that high pass filtering can also cause digital clipping, even if the filter only adds loss. How can this happen? The filter changes phase response which can then change how the different frequencies constructively add in the audio envelope. A good illustration of this is here.

This is a digital problem, not a Windows problem. Thankfully, the same solution used to avoid intersample overs, 4 dB digital preamp loss, should provide enough margin for this in practice as well.
Hi,

Making a filter in Rephase and adjusting the pre-amp inside Rephase should be sufficient to avoid intersample overs, right?

1621688112069.png
 

lizhuoyin

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I think Windows audio driver is used along with Equalizer APO. I did a performance comparison between JAVA and ASIO driver in REW for my MOTU M4:

You can see the ASIO has better THD+N than JAVA driver. Specifically, ASIO has lower noise.
1621810580590.png
 

Offler

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I tested EQ APO and -0.12db limit.

This is 1000Hz sine at -0.14db
sine01.jpg


then 0.12db:
sine02.jpg



Then I did Frequency/distortion measurement at -0,14db:
sine04.jpg


and then at -0,12db

sine03.jpg


Tested equipment was NAD d3020 v2, internal DAC. Its expected SNR around -96db, and THD -80. Values at -0,14db are within specs.
 

daftcombo

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I tested EQ APO and -0.12db limit.

This is 1000Hz sine at -0.14dbView attachment 133914

then 0.12db:
View attachment 133915


Then I did Frequency/distortion measurement at -0,14db:
View attachment 133917

and then at -0,12db

View attachment 133918

Tested equipment was NAD d3020 v2, internal DAC. Its expected SNR around -96db, and THD -80. Values at -0,14db are within specs.
So -0.14dB is a lot better! Thanks.

Can you also do the test with Windows volume set to 98 or 99 VS 100?
 

bennetng

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I tested EQ APO and -0.12db limit.

This is 1000Hz sine at -0.14dbView attachment 133914

then 0.12db:
View attachment 133915


Then I did Frequency/distortion measurement at -0,14db:
View attachment 133917

and then at -0,12db

View attachment 133918

Tested equipment was NAD d3020 v2, internal DAC. Its expected SNR around -96db, and THD -80. Values at -0,14db are within specs.
Can you pass this test when using non-exclusive mode and EQ APO in your setup?
https://www.audiosciencereview.com/...ftware-volume-control.5922/page-2#post-172865
 

Offler

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So -0.14dB is a lot better! Thanks.

Can you also do the test with Windows volume set to 98 or 99 VS 100?
I did. There wasn't any impact on distortion of the sine wave. I tested values of 50, 85 and 100.

Apparently the distortion is caused before volume mixer (i have been told), that is why pre-amp -0.14db gain in EQ APO works, but volume mixer in windows does not.

The explanation that there is CAudioLimiter fits, because when I opened Oscilloscope in the software, sine wave wasn't rising beyond -0.14db - eg. some sw imposed limit was distorting it right before my eyes.

I tested external DAC in my NAD d3020 v2 over Toslink.
AUX input had similar threshold at -3.73db. (roughly -4.0db)
Used output was headphone jack on the amp for both measurements.

My wild guess is that Realtek ALC1220 uses some sort of signal boost (enhancement APO) for its analog outputs, but not for Toslink which is affected only by OS.

It was measured over Realtek ALC1220 Line In, Non exclusive mode, 44.1Khz, 16bit, stereo, because I was trying to test sound format used in PC games.

Software is called Audio Tester V3.0. Shareware and terrible :), and I used it only for confirmation of the advices I got.

Edit some other screens:

This is 1Khz sine wave at -0,14db. I adjusted volume on the amplifier to fit the lines, to make it more visible.
wave01.jpg


This is 1KHz sine at -7,7dB. As you can clearly see its smaller, and that is correct.
wave02.jpg


And this is 1KHz at +10db, and its of same size as the first one. That is definitely NOT correct, and it counts as distortion.
wave03.jpg
 
Last edited:

Offler

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Can you pass this test when using non-exclusive mode and EQ APO in your setup?
https://www.audiosciencereview.com/...ftware-volume-control.5922/page-2#post-172865

I believe more to my eyes, than to my ears :D so I run it through software oscilloscope. (the one in audiotester and the one in Foobar)

I played the a.mp3 over PowerDVD where i can easily switch from/to exclusive mode.

Exclusive mode - always reaching the threshold line.
Shared Mode, -12db - looks similar to B.mp3.

-0,14dB the flat parts of the clipped wave are touching the lines and again as in case of 1KHz sinewave, it does not go much beyond the threshold.

at -2.0 it looks like this:
wave04.jpg


Since the wave itself is clipping, you can see that the volume mixer in EQ APO lowered the amplitude in shared mode.
 

daftcombo

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I did. There wasn't any impact on distortion of the sine wave. I tested values of 50, 85 and 100.

Apparently the distortion is caused before volume mixer (i have been told), that is why pre-amp -0.14db gain in EQ APO works, but volume mixer in windows does not.

The explanation that there is CAudioLimiter fits, because when I opened Oscilloscope in the software, sine wave wasn't rising beyond -0.14db - eg. some sw imposed limit was distorting it right before my eyes.

I tested external DAC in my NAD d3020 v2 over Toslink.
AUX input had similar threshold at -3.73db. (roughly -4.0db)
Used output was headphone jack on the amp for both measurements.

My wild guess is that Realtek ALC1220 uses some sort of signal boost (enhancement APO) for its analog outputs, but not for Toslink which is affected only by OS.

It was measured over Realtek ALC1220 Line In, Non exclusive mode, 44.1Khz, 16bit, stereo, because I was trying to test sound format used in PC games.

Software is called Audio Tester V3.0. Shareware and terrible :), and I used it only for confirmation of the advices I got.

Edit some other screens:

This is 1Khz sine wave at -0,14db. I adjusted volume on the amplifier to fit the lines, to make it more visible.
View attachment 134064

This is 1KHz sine at -7,7dB. As you can clearly see its smaller, and that is correct.View attachment 134065

And this is 1KHz at +10db, and its of same size as the first one. That is definitely NOT correct, and it counts as distortion.
View attachment 134066
Very interesting, thank you.

I think I'll stick to -4.0 dB in EqAPO (as OP recommended) and 100% on Windows from on, except to use with devices without volumes control.
 
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