Home Theater Forum and Systems banner

Software equalizer for use with REW on Windows

126K views 232 replies 54 participants last post by  ja00 
#1 ·
Hi,
this post is about Equalizer APO, an open source equalizer for Windows. (as it is free, this should not be regarded as advertising)

I have been using Room EQ Wizard for some time together with a BFD and with the kX driver but could not find a system-wide equalization solution in software that just works on all sound cards. When I adopted Windows 7 as my primary operating system I noticed its integrated home theater effects, which are available with many sound card drivers but which do not include a parametric equalizer. As I found out, it is possible to develop custom audio effects since Windows Vista and so I began working on this missing feature. I call the result "Equalizer APO".

Equalizer APO is a system-wide parametric equalizer for Windows. It is implemented as an Audio Processing Object (APO) for the system effect infrastructure introduced with Windows Vista. The reason I post this in the REW forum is that Equalizer APO can use the filter settings from REW with minimal effort by just exporting the filter settings as a text file, which becomes a configuration file for Equalizer APO. In contrast to most hardware equalizers there are virtually no limits on filter count and channel count.

You can find more information at http://sourceforge.net/projects/equalizerapo and, of course, download the installer. I would really appreciate some feedback. If you have any questions or objections, please reply to this post.
 
See less See more
#114 · (Edited)
Therefore, measuring the other channels with the sub turned off leads to a wrong measurement, as it will not take into account the sound your subwoofer will put out when sound is fed to the other channels. Thus, the first method should deliver better results.

To verify the result, you can measure again after completing the EQ configuration, but this time not through ASIO but using the normal "Java" audio output, without routing to a specific channel. Then you see the resulting frequency response as if playing back a normal stereo source. You should see a better equalization here using the first method (measuring with subwoofer on).
i was arrived at the same conclusion
If you have only one speaker for the low frequencies anyway, you could also use this measurement to create the filters for the lower frequency range and just apply it to all channels and then just create individual filter sets for the higher frequencies (see where the frequency responses for the channels begin to differ).
i did not think of this possibility, i will try (i have only one sub of course). Do you think this method is better then the one above ?

edit : question for bass limited filters+ sub for all
suppose you play a low frequency (say 50hz) to the left channel
- in the first eq (all channel in full range eq + sub eq for sub)
50hz goes to Left channel EQ with Left filter (full range), goes to the ampli (5 small +1 sub). The 50hz are routed to the sub
- in the second eq (all channel in bass limited eq + sub eq for all)
50hz goes to Left channel EQ with Left filter (bass limited)+ sub => no 50 hz goes to the ampli ???

an explanation is "....sets for the higher frequencies... " is different from bass limited form REW filters creation
 
#116 ·
i was arrived at the same conclusion
i did not think of this possibility, i will try (i have only one sub of course). Do you think this method is better then the one above ?
The results should be the same, so it might just mean less work for you. But if you are already comfortable with equalizing the full range on each channel separately, there's no need to change the method.

suppose you play a low frequency (say 50hz) to the left channel
- in the first eq (all channel in full range eq + sub eq for sub)
50hz goes to Left channel EQ with Left filter (full range), goes to the ampli (5 small +1 sub). The 50hz are routed to the sub
- in the second eq (all channel in bass limited eq + sub eq for all)
50hz goes to Left channel EQ with Left filter (bass limited)+ sub => no 50 hz goes to the ampli ???
Yes, if you cut the frequency response of the left channel, the low frequencies for that channel will be lost, as the redirection to the subwoofer channel only happens inside your amplifier. Maybe you misunderstood me, I meant that you use channel specific filters for higher frequencies and instead of creating individual filters for the lower frequencies you just use the same set for all channels. This means, the bass response is not cut as the channel specific filters do not change the response for lower frequencies. But, as I already said, if it is easier for you to create full-range filters for each channel, just do that, it might even be more exact.
 
#115 ·
Hello! I have just installed your fantastic software on my win 7 machine. However, i have a problem.

APO is configured to equalize my roland quad-capture soundcard, but it appears to work only in foobar (which usually set the output to "default audio driver".However after installing APO it shows nothing selected in the output tab, but it works).

When i use a software that set the output to quad capture 1-2 instead of default audio driver (REW or ableton live for example), it seems that apo is bypassed.

To test this, i ran a measurement in rew from the program, and the frequency response didn't change. But when i ran some pink noise through foobar and analyzed it with rew rta, the frequency response was indeed equalized.

I'm trying to get perfect room equalization for mixing so the fact that i can't use it in ableton live is abig problem for me. Any way to solve this problem?

Thanks
 
#117 ·
APO is configured to equalize my roland quad-capture soundcard, but it appears to work only in foobar (which usually set the output to "default audio driver".However after installing APO it shows nothing selected in the output tab, but it works).
This is strange, E-APO should not change the selectable sound devices at all.

When i use a software that set the output to quad capture 1-2 instead of default audio driver (REW or ableton live for example), it seems that apo is bypassed.
This sounds like you are using ASIO for output. Make sure that you select "Java Audio" in REW. I don't know Ableton Live, but it also seems to have a "DirectX" output mode. You can use that and it should work. However, as this is a program for music production, you might need ASIO for latency reasons. I'm afraid, there's no way to support ASIO output in E-APO.

If "Quad capture 1-2" is just another normal(non-ASIO) audio device, make sure that you have installed E-APO for that device in the Configurator.

I'm trying to get perfect room equalization for mixing so the fact that i can't use it in ableton live is abig problem for me. Any way to solve this problem?
If you need room equalization when using ASIO, you might be able to utilize the audio effects contained in Ableton Live, which seems to include parametric filters.
 
#118 ·
Ah, yes, that's the problem... i was unaware that apo doesn't work with ASIO. Ok, i will use java audio in rew and fafbilter pro q in ableton on the master output... should do the trick :) thanks for the answer and for the software ;)

oh, another question, a little OT. Do you think it's better to use linear phase or normal EQ for roomEQ purposes? I have the possibility to use both in ableton..
 
#120 ·
oh, another question, a little OT. Do you think it's better to use linear phase or normal EQ for roomEQ purposes? I have the possibility to use both in ableton..
I don't know much about that. I guess that "normal" EQ means a minimal phase EQ. Quality wise, linear phase EQ should be better, as it doesn't change the phase response of your signal. However, linear phase equalization normally also means a higher latency for the output signal. Therefore, the normal EQ might be the better choice if you have low latency requirements. By the way, Equalizer APO is not a linear phase EQ.

Sorry to bother you again, but i just realized i don't have the java audio options in REW. I have the last se installed on my system, but i don't know how to activate java audio. I've searched on the web but i can't find an answer. Should i download some additional java packages?
If you are using the latest release (5.0), then it always uses the "Java" audio output. I'm using the beta version, which supports ASIO, and thought that you might be using it as well. If the Equalizer APO is not working with the release version, make sure that you have selected the correct audio output device (the one that you selected in E-APO's Configurator) in the preferences.
 
#119 ·
Sorry to bother you again, but i just realized i don't have the java audio options in REW. I have the last se installed on my system, but i don't know how to activate java audio. I've searched on the web but i can't find an answer. Should i download some additional java packages?
 
#122 ·
Exactly what is needed to get the processed signal with APO filters engaged to play through a digital output while using foobar? It plays just fine through the headphone output. I have the Audio Advantage MicroII USB toslink adapter from Turtle Beach that I'm sending to an outboard DAC.
 
#123 ·
Hello,
Since last week REW and EQ APO is running on my notebook ( notebook working as a music server ).
Both tools are fantastic software.

What I'am thinking about is to find a way to setup a crossover with EQ APO for my 2-way satellites.
I use MusicBee as player and send the datas via HDMI to AVR 4310.
I have a 2.1 configuration, satellites and subwoofer ( satellites with byamping).
The filters and channels of EQ APO are able to do this.
But I'am not sure how to configure the channels for the right signals and what my AVR is doing sending a 4channel signal. May be my idea is complete impossible, I'am not so familiar with Surround behaviours.
Does somebody have a comment?
 
#125 ·
What I'am thinking about is to find a way to setup a crossover with EQ APO for my 2-way satellites.
I use MusicBee as player and send the datas via HDMI to AVR 4310.
I have a 2.1 configuration, satellites and subwoofer ( satellites with byamping).
The filters and channels of EQ APO are able to do this.
But I'am not sure how to configure the channels for the right signals and what my AVR is doing sending a 4channel signal. May be my idea is complete impossible, I'am not so familiar with Surround behaviours.
Does somebody have a comment?
I suppose that could be technically possible. If I'm following what you want to do by using your AVR and Laptop with EQ APO as an active crossover. It appears like EQ APO could be used for this purpose but for it to work properly you'd need a program that ouputs Stereo as a Surround Sound format by doubling the L & R signal to the rear surrounds so you can use EQ APO to split the signals. Alas I do not know of such a program. :/
 
#124 ·
I was very happy when I found this project. But it doesn't seem to work for me. :(

I installed the v0.8 x64 version for Windows 8.1 x64 (Enterprise), enabled the APO for the AMD HDMI output (which I am using for my HDMI A/V Receiver) and I also unticked the "Disable all enhancements" in the audio control panel. I rebooted the machine (full reboot, not the tricky semi-hibernation of Win8, I keep that disabled anyway). But nothing seems to work.

I also set Winamp from WASAPI Exclusive to DirectSound (and I unticked the hardware acceleration, just in case - even though there is no such thing as DirectSound hardware acceleration since Vista).

There is zero difference from changing the Preamp value to anything and I could not find any log files.
 
#126 ·
Yes, that's correct. The main problem is to double the stereo signal after the player.
MusicBee can use Winamp output plugins and of course their own, but I have not found the right thing.
Inside the player is the possibility to generate 5.1 from stereo, but I think this will include surround effects.
 
#127 · (Edited)
i think your solution is to use MULTI CH STEREO with your Denon ( i have a 2312 and i can do that). this mode copy the front to to rear BUT as this mode is after EQ APO you can't apply special filters to rear

if you want to apply different filters on each channel, you have to use matrix software. Personnaly, for Home Cinema i use MPC-HC and ffdshow (ffdaudio). ffdaudio (ac3filter is an other possibility) can matrix channels as you want. Your Denon will turn in MULTI CH IN.

I don't know the quality of all this plugin but for movies and my ears, it's good enough
 
#128 ·
I just compiled the last trunk snapshot with MSVC 2012 but it still doesn't work on Windows 8.1 x64. How could I help to get it working? (I am not a real programmer, so I don't know where to start the debugging in this case when something just don't work at all, so there is no error log or something to get me started...)
 
#130 ·
Thanks to have a notice to my problem.
I have not known this virtual audio cable before.
I think with foobar and a filter plugin it should be also possible.
At the moment I stopped working on this, because my blu ray player and the tv is connected to the av receiver.
Active loudspeaker setup from computer side will not support this applications.
If I have new ideas, I try again for a solution.
 
#131 · (Edited)
Hello.

I have a 1/3 oct Graphics Equalizer project on going for to extend the usability of EqualizerAPO software. My project is fully open and free from cost (whole project can be downloaded (32-bit binaries included)).

http://img545.imageshack.us/img545/3195/ar7y.jpg

If interested, you can check my site @ http://jiiteepee.tripod.com/home.html

Edit: Few users confirmed that this 32-bit version of EQ31GUI-2 works on Vista, 7 and 8 (32-bit/64-bit).

Juha
 
#132 ·
Hello,

I have installed EQ APO on Windows 7 Ultimate along with M-Audio 1010 LT sound card and it seems, that it is working fine. For example, I hear extreme change in sound, when I add the following filter in the config.txt

Command: Parameters
Preamp: -0 db
Filter 1: ON PK Fc 500 Hz Gain -90.0 dB Q 10.00

My problem is, that I want to realize an extreme low cut filter on my complete system. So used a high pass filter like this, but it makes no difference. My thought was, that I cut everything under 5000 hz with this high pass filter, but nothing happens.

Command: Parameters
Preamp: -0 db
Filter 1: ON HPQ Fc 5000.0 Hz Q 10.500

Could somebody give me text line with a low cut (=high pass) filter, that cuts everthing under 30 hz?


Thank you
 
#133 · (Edited)
Hello,

I have installed EQ APO on Windows 7 Ultimate along with M-Audio 1010 LT sound card and it seems, that it is working fine. For example, I hear extreme change in sound, when I add the following filter in the config.txt

Command: Parameters
Preamp: -0 db
Filter 1: ON PK Fc 500 Hz Gain -90.0 dB Q 10.00

My problem is, that I want to realize an extreme low cut filter on my complete system. So used a high pass filter like this, but it makes no difference. My thought was, that I cut everything under 5000 hz with this high pass filter, but nothing happens.

Command: Parameters
Preamp: -0 db
Filter 1: ON HPQ Fc 5000.0 Hz Q 10.500
Could somebody give me text line with a low cut (=high pass) filter, that cuts everthing under 30 hz?


Thank you
EqAPO is a biquad system so the filter is 2nd order and has a slope of 6dB/oct.
When you use single 2nd order HP filter @ 30Hz, the attenuation is just 6 dB @ 15Hz which result you can't hear.

You can cascade filters so try this (48dB/oct)

Filter 1: ON HP Fc 30.0 Hz
Filter 1: ON HP Fc 30.0 Hz
Filter 1: ON HP Fc 30.0 Hz
Filter 1: ON HP Fc 30.0 Hz
Filter 1: ON HP Fc 30.0 Hz
Filter 1: ON HP Fc 30.0 Hz
Filter 1: ON HP Fc 30.0 Hz
Filter 1: ON HP Fc 30.0 Hz

or double that to get 96dB/oct.

Juha
 
#134 · (Edited)
Thanks for the answer! Just for the people, who read this: I want to realize an extreme low cut filter (=high pass) for frequencies under 30 HZ (...or any other value)

First I tried this:

Command: Parameters
Preamp: -0 db
Filter 1: ON HP Fc 3000.0 Hz
Filter 2: ON HP Fc 3000.0 Hz
Filter 3: ON HP Fc 3000.0 Hz
Filter 4: ON HP Fc 3000.0 Hz
Filter 5: ON HP Fc 3000.0 Hz
Filter 6: ON HP Fc 3000.0 Hz
Filter 7: ON HP Fc 3000.0 Hz
Filter 8: ON HP Fc 3000.0 Hz
Filter 9: ON HP Fc 3000.0 Hz
Filter 10: ON HP Fc 3000.0 Hz

Then I tried this:

Command: Parameters
Preamp: -0 db
Filter 1: ON HP Fc 3000.0 Hz
Filter 1: ON HP Fc 3000.0 Hz
Filter 1: ON HP Fc 3000.0 Hz
Filter 1: ON HP Fc 3000.0 Hz
Filter 1: ON HP Fc 3000.0 Hz
Filter 1: ON HP Fc 3000.0 Hz
Filter 1: ON HP Fc 3000.0 Hz
Filter 1: ON HP Fc 3000.0 Hz
Filter 1: ON HP Fc 3000.0 Hz
Filter 1: ON HP Fc 3000.0 Hz

Both did no changes to the sound. I did check it again and for example this gives me an extreme sound change, so the eq does work

Command: Parameters
Preamp: -0 db
Filter 1: ON PK Fc 500 Hz Gain -60.0 dB Q 10.00

Any other suggestions? I just want to free my two active stereo monitors from deep frequencies.

BTW: It's the 32 Bit 0.7 Version of APO EQ
 
#137 ·
(sorry for double Post)

OK, checked this and now I can confirm that HP filter does not work as it should.
That's very sad, but I think it might come in further versions..? HP/LP filters, that are very "steep" can be very useful to kill unwanted frequencies.

In my case I have Adam P11 A monitors and they are absolute useless under 30 HZ (or even maybe under 50 HZ), so I wanted to use HP filter for them.

Apart from that, the whole idea of the software is just brilliant.

Greetz from Hamburg, Germany.
 
#139 ·
(sorry for double Post)



That's very sad, but I think it might come in further versions..? HP/LP filters, that are very "steep" can be very useful to kill unwanted frequencies.

In my case I have Adam P11 A monitors and they are absolute useless under 30 HZ (or even maybe under 50 HZ), so I wanted to use HP filter for them.

Apart from that, the whole idea of the software is just brilliant.

Greetz from Hamburg, Germany.
Since EqAPO supports only 2nd order filters you need to use that cascading method I show earlier to get a steep one. I have suggested the developer to add support for raw coefficient input so lets wait and see...

Juha
 
#140 ·
I read all 14 pages to try and eliminate my question, but I'm not fully clear. At this point, is ASIO compatible with APO EQ? I'm using the RME UFX, right now I am using an eq on the master bus in Reaper and PT with the eq setting derived from REW, I just liked the idea of not having to worry about using anything in the DAW.

Thanks
 
#154 ·
I didn't think it would be anything reproducible. Like you I'm stumped though. It could have just been the computer gremlins at work!

No worries about the data loss. I got most of it back and what I haven't recovered I should have squirreled away somewhere. As I said I did learn a valuable lesson about keeping current backups that I won't soon forget.

I did run a Microsoft update about the same time I installed E-APO though and I wonder if that could have been a factor in what I refer to as "the Win 7 debacle".

Ah well just one of those things I suppose but I'm glad the software does work so well for others.
 
#155 · (Edited)
Is it possible to add time delay to individual channels? If not is this a feature that can be implemented? So far the PEQ works amazing and with the ability to set crossover points and channel delay a person could make a simple HTPC that performs as good as most AVRs with the ability to manually adjust all the settings. Great piece of software BTW.

Edit: Just saw the post for the Feature Request for delay on the Sourceforge page. I'm very happy to hear you are working on it already.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top