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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.
 
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#160 ·
hello,
sometimes (randomly ?) EQ-APO don't work with my AMD HDMI audio.
i just notice that in this case in configurator.exe the select box are uncheck (and i don't do that by myself obviously).
- my HDMI is plug to my AVR so when i use my monitor, my HDMI is disconnected (mono screen) i switch to VP only ( when wathing movies) or dual screen (when testing). (all of that are automatic)
- it seems that the uncheck appears after wake up from hibernation (not sure, i have to investigate)

Remarks : my OS win7x64sp1
- the GUI of configurator.exe are in german (both 0800 et now 0801)
- in 0801 when you check/uncheck a box it asks you to reboot, this does not appear in 0800.
( but in registry, even if you refuse reboot (0801) , Child_APO are update. no test yet to heard if active nevertheless , i am at work )
So my question :
- can you help me a way to search ( i have no try yet to log what happen) ?
- is it possible to stop asking for reboot in 0801 AND offer the possibility of command line to force check ?
 
#161 ·
Remarks : my OS win7x64sp1
- the GUI of configurator.exe are in german (both 0800 et now 0801)
So you are getting a german UI although your OS is french? This should not happen, it should be english.
- can you help me a way to search ( i have no try yet to log what happen) ?
Could you please export the registry path HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\MMDevices\Audio\Render when the check box is enabled (the correct state) and then again when you find that it has been disabled somehow(the broken state)? Then I could see the difference and see if I can do something about it.
- is it possible to stop asking for reboot in 0801 AND offer the possibility of command line to force check ?
I noticed that in Windows 8.1 the registry changes are only applied when the audio service is restarted, so I ask to reboot as I can't reliably restart a service (there may be dependencies). This was not needed in Windows 7, there the changes seem to be applied without restarting the audio service. I didn't think that it would hurt anyone to reboot one time to make sure the changes are applied, as you should not need to enter the Configurator regularly, normally only as part of the installation. But, as you request, I will disable this behaviour for Windows 7.
 
#163 ·
Hello,

I have a first setup using EQ APO as active crossover via HDMI to my AV receiver.
It sounds fantastic although I cannot use REW for equalization at the moment.
This setup is only valid for my Hardware / Software configuration.
If somebody will follow, an idividual setup will be necessary.

This are the EQ APO settings:

Filter Settings file

Notes:

Equaliser: Generic

# Midwoofer
Channel: 5 SL
Filter 1: ON LPQ Fc 2000 Hz Q 0.500
#Filter 2: ON LPQ Fc 2000 Hz Q 0.500

Channel: 6 SR
Filter 1: ON LPQ Fc 2000 Hz Q 0.500
#Filter 2: ON LPQ Fc 2000 Hz Q 0.500

#Tweeter
Channel: 1 L
Preamp: 0 dB
Filter 1: ON HPQ Fc 2000 Hz Q 0.500
Filter 2: ON HPQ Fc 2000 Hz Q 0.500

Channel: 2 R
Preamp: 0 dB
Filter 1: ON HPQ Fc 2000 Hz Q 0.500
Filter 2: ON HPQ Fc 2000 Hz Q 0.500

Channel: 4 SUB
Preamp: -6 dB

This is a crossover between midwoofer and tweeter.
Cascading the first order filter works for higher order filtering.
For the first setup I use Bessel filters.

The main problem for the crossover setup is to generate 5 channels with the same signals from the media player. I use MusicBee and in the preferences I can set 5.1 for the output to get the same on 5 channels.

The next step is to configurate the HDMI output. I don't know if this is possible for every laptop or PC.
I have a Packard Bell Easy Note and HDMI configuation is possible as followed:
5.1 Surround: Front L,R Surround L,R Subwoofer

Then I have changed the AV receiver settings. I have a Denon AVR 4310.
In the Surround Mode I have set Multi CH Direct.
Auto Surround Mode: ON

Unfortunately I cannot use REW for the complete measurement at the moment.
This is becasue the 5.1 output is only vaild for MusicBee.
REW is using only the front channels, which are connected to my tweeters at the moment.

For microphon measurements I use frequency sweeps with MusicBee and check the results in a software audio analyzer. I miss REW to compensate my room modes, may be I have to do this by hand.
Or somebody has an idea...

At the moment I check the result with my well known recordings.
But already after 15 minutes of listening I can say room impression and clarity is fantastic.
 
#167 ·
...

Filter Settings file

Notes:

Equaliser: Generic

# Midwoofer
Channel: 5 SL
Filter 1: ON LPQ Fc 2000 Hz Q 0.500
#Filter 2: ON LPQ Fc 2000 Hz Q 0.500

Channel: 6 SR
Filter 1: ON LPQ Fc 2000 Hz Q 0.500
#Filter 2: ON LPQ Fc 2000 Hz Q 0.500

#Tweeter
Channel: 1 L
Preamp: 0 dB
Filter 1: ON HPQ Fc 2000 Hz Q 0.500
Filter 2: ON HPQ Fc 2000 Hz Q 0.500

Channel: 2 R
Preamp: 0 dB
Filter 1: ON HPQ Fc 2000 Hz Q 0.500
Filter 2: ON HPQ Fc 2000 Hz Q 0.500

Channel: 4 SUB
Preamp: -6 dB

...
Hmm... is that just because of compatibility when you give the channel position using format "Channel: <channel number> <acronym of same channel>" ?

From Wiki: "Selects the channels to which the following Filter and Preamp commands will be applied. Channel positions can be given by identifier (acronym of 1 up to 3 characters) or by number (counted from 1). The supported channel configurations are listed below. If a channel configuration is not supported, channels can only be selected by number. Multiple channels can be specified by separating with space. The special position "all" selects all channels. (added in version 0.8)"

I have not checked this but, does using that type formatting double the filters if channel configuration is supported?
 
#164 ·
I don't know if it answer to your question but with virtual audio cable (not free) you can have one channel (rew) for input and any number of channels (vac) for output.
the great advantage with vac is that Eq-APO works with it
if your needs is only one channel at a time ASIO4all is an anwser (but Eq_APO does'nt work).
for me HDMI with AVR2313, with vac i use rew one channel at a time for output so i can create EQ-APO filters for each channel and test the result with rew.
( i never try to output all the channels in the time )
 
#165 ·
I have checked with VB Hifi cable and VB Virtual audio cable without success to have all channels in the time.
The problem seems it is not possible to set the single channels as input in EQ APO, but I'm not sure.
I also think about REW measurements with one channel at a time. I can do it routing the actual channel to the front speakers in the AV receiver. May be with vac it is a bit more smart.
Anyway, best solution would be to have all channels in the time. May be in the next version of EQ APO :heehee:
 
#166 ·
my english is so poor that i can't be sure i understand what you say.
-in REW i select Line 1 (vac) for output device
-in Audio Repeater MME (vac) wave in=line1 , wave out =HDMI ,channel config=custom,
if channel=1 you choose which channel you want
if channel=5 i saw that only FL, FR works on the 5 selected
if channel=3 FC BL, BR works i don't test every combinations but it's a VAC bug.
in ALL the case, EQ-APO works well you just have to say the channels you want to filter
(by Channel: name)
as i say before the great advantage with vac is that you use rew with one channel at a time including rear and to be compatible with EQ-APO.
i don't understand your last phrase : EQ-APO and the five channels ? I think you speak about REW. in this case i agree with you, it would be the best thing.
 
#168 ·
This are measurements regarding the filter settings as in my former email.
Only as example to show that cascading works.

Midwoofer 6db / oct


Tweeter 12db / oct


I will check your notice about channel selection, although seems it works.
The measurements are Stereo ( both satellites ) with the microphon at the hearing position.

My problem is, I cannot measure the complete setup at the time, only single channels.
Is there no possibility inside EqApo to copy the incoming stereo signal to other channels?
 
#169 ·
Until now no VAC is running well on my laptop.

But I have a new methode to measure midwoofer and tweeter together.
It looks a bit adventuresome, but seems it works.

I have generated a fast frequency sweep at www.audiocheck.net
It is running under MusicBee including all channels together, while REW is running the measurement for the front speakers only.
This are the results:


The red curve is the standard measurement with REW, it is only the midwoofer.
The blue curve is the REW measurement and the frequency sweep of MusicBee together.
I don't know if this methode is perfect, but until I do not have another possibility I take it.
The sweep works good in the mid and high frequency range, but is not enough to catch the subwoofer behavior. So I don't know what my subwoofer is doing. May be I have to generate another sweep especially for the subwoofer range.
But for today it is enough.
 
#174 ·
That's currently not possible, but might come in the future.

I have tried to use REW´s auto eq just like I did the first time but with no succes. When I save the parameters file, my windows volume bar shows my laptop is outputting inaudible signal at full volume. Sometimes I only get audio from left channel and sometimes both. If I tried to increase volume from windows, I might get audio from both channels but would lose it when volume is higher than ~50%
Make sure that the audio signal isn't clipped. Insert a negative preamp to make sure the resulting signal never gets above 1.0 . In your example below, you could insert a preamp of -3 dB for example.

I can´t figure out why it does this. Can it have something to do with the fact that the filters overlap a little? For (bad)example:
Filter 1: ON PK Fc 63,4 Hz Gain -12,9 dB Q 5
Filter 2: ON PK Fc 54 Hz Gain 3 dB Q 1
I can see no problem with these filters. Overlapping filters are definitely supported, you can even set multiple filters at the exact same frequency.

Edit* It seems like the problem is the filter file which REW gives me when I go Files-Export-Export filters in txt(something like that) I can manually edit the filters file as much as I want. I still would like this to work like I feel it´s supposed to.
This should work. Please check that the file is really written to when you overwrite an existing file. I remember one situation where the file was not written.
 
#173 · (Edited)
I have sort of a problem.

I use eq-apo to get rid of about 22db boost at arround 50hz, which it does just like it´s supposed to do.

I have tried to use REW´s auto eq just like I did the first time but with no succes. When I save the parameters file, my windows volume bar shows my laptop is outputting inaudible signal at full volume. Sometimes I only get audio from left channel and sometimes both. If I tried to increase volume from windows, I might get audio from both channels but would lose it when volume is higher than ~50%

I can´t figure out why it does this. Can it have something to do with the fact that the filters overlap a little? For (bad)example:
Filter 1: ON PK Fc 63,4 Hz Gain -12,9 dB Q 5
Filter 2: ON PK Fc 54 Hz Gain 3 dB Q 1

Edit* It seems like the problem is the filter file which REW gives me when I go Files-Export-Export filters in txt(something like that) I can manually edit the filters file as much as I want. I still would like this to work like I feel it´s supposed to.
 
#175 · (Edited)
Hello again.

I haven´t had time to play with eq apo until this morning.

Here is what I did:

Disable eq apo > run rew > click measure > click check levels > adjust level by increasing volume from amp(pc volume is always 100%) > make measurement > click EQ button > Equalizer=generic,

Target settings: Speaker type=Full range, LF cutoff=0,
Target level=adjust until rew stops whining, something between 60 and 80, Filter tasks: Match range from 10 to 10,000, individual max boost=6db, overall max boost=0, Flatness target=1 or 3.

Then I click match range to target button > File-export-export filters as txt.

Everything works just fine until the point where I edit eq apo config file to include the file created in previous step. No sound at all. If i delete line or two from "Example.txt" so it only has ~10 lines, windows mixer and/or volume slider shows me there is constant -0db signal coming out. Foobar2000, vlc, mpc, firefox or any other application does not give me sound at all.



This does not work:

Filter 1: ON PK Fc 226 Hz Gain 1,9 dB Q 1,58
Filter 2: ON PK Fc 47,4 Hz Gain -20,2 dB Q 8,00
Filter 3: ON PK Fc 421 Hz Gain 4,3 dB Q 2,38
Filter 4: ON PK Fc 1044 Hz Gain 0,7 dB Q 1,88
Filter 5: ON PK Fc 64,6 Hz Gain -6,8 dB Q 10,69
Filter 6: ON PK Fc 72,3 Hz Gain 1,2 dB Q 2,00
Filter 7: ON PK Fc 2336 Hz Gain 0,6 dB Q 1,45
Filter 8: ON PK Fc 399 Hz Gain -0,5 dB Q 5,86
Filter 9: ON PK Fc 310 Hz Gain -0,5 dB Q 6,52
Filter 10: ON PK Fc 203 Hz Gain -1,4 dB Q 37,72
Filter 11: ON PK Fc 1218 Hz Gain -0,5 dB Q 7,56
Filter 12: ON PK Fc 309 Hz Gain -0,5 dB Q 8,28
Filter 13: ON PK Fc 2579 Hz Gain -0,5 dB Q 6,87
Filter 14: ON PK Fc 1118 Hz Gain -0,5 dB Q 6,11
Filter 15: ON PK Fc 2397 Hz Gain -0,5 dB Q 6,98
Filter 16: ON PK Fc 399 Hz Gain -0,5 dB Q 9,53
Filter 17: ON PK Fc 395 Hz Gain -0,5 dB Q 7,50
Filter 18: ON PK Fc 242 Hz Gain -0,5 dB Q 7,22
Filter 19: ON PK Fc 541 Hz Gain -0,5 dB Q 8,48
Filter 20: ON PK Fc 204 Hz Gain -0,5 dB Q 19,12

This does work fully, just like it´s supposed to:

Filter 1: ON PK Fc 226 Hz Gain 1,9 dB Q 1,58
Filter 2: ON PK Fc 47,4 Hz Gain -20,2 dB Q 8,00
Filter 3: ON PK Fc 421 Hz Gain 4,3 dB Q 2,38
Filter 4: ON PK Fc 1044 Hz Gain 0,7 dB Q 1,88
Filter 5: ON PK Fc 64,6 Hz Gain -6,8 dB Q 10,69
Filter 6: ON PK Fc 72,3 Hz Gain 1,2 dB Q 2,00
Filter 7: ON PK Fc 2336 Hz Gain 0,6 dB Q 1,45
Filter 8: ON PK Fc 399 Hz Gain -0,5 dB Q 5,86
Filter 9: ON PK Fc 310 Hz Gain -0,5 dB Q 6,52
Filter 10: ON PK Fc 203 Hz Gain -1,4 dB Q 37,72
Filter 11: ON PK Fc 1218 Hz Gain -0,5 dB Q 7,56
Filter 12: ON PK Fc 309 Hz Gain -0,5 dB Q 8,28
Filter 13: ON PK Fc 2579 Hz Gain -0,5 dB Q 6,87

I have no use for this kind of filter settings. Just something to show you my problem.
 
#176 ·
This does not work:
[...]
I just inserted these lines into my config.txt and I had no issues at all (Equalizer APO 0.8.1).

Could you please run the benchmark application (Benchmark.exe) with the working configuration and with the one that produces silence and look at the resulting files (%temp%/testout.wav)? To make this work, your config file either has to contain no Device command at all or the command has to include the device "Benchmark". This will show if the filtering algorithm is causing your issues.
 
#177 ·
For some reason it didn´t cause any kind of problems for me either.

I will have to play a little with rew and eq apo and see if problems actually are solved by them selves.

Thank you for your reply and any help so far. I will come back if I encounter any further difficulties with this software.
 
#178 ·
Here I am again.

Last night I thought the problem had magically solved by itself.

About a minute ago I used old measurement to create filter config file to see if everything still works.

This does work:

Spoiler
Filter Settings file

Room EQ V5,00
Dated: 15.5.2014 7:37:41

Notes:

Equaliser: Generic
huhti 9 11:12:28
Filter 1: ON PK Fc 47,5 Hz Gain -17,7 dB Q 8,00
Filter 2: ON PK Fc 5945 Hz Gain -4,9 dB Q 3,36
Filter 3: ON PK Fc 63,0 Hz Gain 5,5 dB Q 2,44
Filter 4: ON PK Fc 6796 Hz Gain 3,3 dB Q 2,35
Filter 5: ON PK Fc 64,9 Hz Gain -8,6 dB Q 9,47
Filter 6: ON PK Fc 387 Hz Gain 2,8 dB Q 2,71
Filter 7: ON PK Fc 247 Hz Gain 4,3 dB Q 3,20
Filter 8: ON PK Fc 38,0 Hz Gain -9,0 dB Q 11,68
Filter 9: ON PK Fc 2755 Hz Gain 1,1 dB Q 2,27
Filter 10: ON PK Fc 4896 Hz Gain -14,8 dB Q 28,89
Filter 11: ON PK Fc 73,1 Hz Gain -0,5 dB Q 3,75
Filter 12: ON PK Fc 3108 Hz Gain -0,5 dB Q 6,51
Filter 13: ON PK Fc 6001 Hz Gain -0,9 dB Q 2,62
Filter 14: ON PK Fc 518 Hz Gain -0,5 dB Q 6,74
Filter 15: ON PK Fc 3352 Hz Gain -0,5 dB Q 5,81
Filter 16: ON PK Fc 335 Hz Gain -0,5 dB Q 7,85
Filter 17: ON PK Fc 238 Hz Gain -0,5 dB Q 8,98
Filter 18: ON PK Fc 2828 Hz Gain -0,5 dB Q 8,32


This doesn´t:
Spoiler
Filter Settings file

Room EQ V5,00
Dated: 15.5.2014 7:37:41

Notes:

Equaliser: Generic
huhti 9 11:12:28
Filter 1: ON PK Fc 47,5 Hz Gain -17,7 dB Q 8,00
Filter 2: ON PK Fc 5945 Hz Gain -4,9 dB Q 3,36
Filter 3: ON PK Fc 63,0 Hz Gain 5,5 dB Q 2,44
Filter 4: ON PK Fc 6796 Hz Gain 3,3 dB Q 2,35
Filter 5: ON PK Fc 64,9 Hz Gain -8,6 dB Q 9,47
Filter 6: ON PK Fc 387 Hz Gain 2,8 dB Q 2,71
Filter 7: ON PK Fc 247 Hz Gain 4,3 dB Q 3,20
Filter 8: ON PK Fc 38,0 Hz Gain -9,0 dB Q 11,68
Filter 9: ON PK Fc 2755 Hz Gain 1,1 dB Q 2,27
Filter 10: ON PK Fc 4896 Hz Gain -14,8 dB Q 28,89
Filter 11: ON PK Fc 73,1 Hz Gain -0,5 dB Q 3,75
Filter 12: ON PK Fc 3108 Hz Gain -0,5 dB Q 6,51
Filter 13: ON PK Fc 6001 Hz Gain -0,9 dB Q 2,62
Filter 14: ON PK Fc 518 Hz Gain -0,5 dB Q 6,74
Filter 15: ON PK Fc 3352 Hz Gain -0,5 dB Q 5,81
Filter 16: ON PK Fc 335 Hz Gain -0,5 dB Q 7,85
Filter 17: ON PK Fc 238 Hz Gain -0,5 dB Q 8,98
Filter 18: ON PK Fc 2828 Hz Gain -0,5 dB Q 8,32
Filter 19: ON PK Fc 386 Hz Gain -0,5 dB Q 7,15
Filter 20: ON PK Fc 257 Hz Gain -0,5 dB Q 8,66



Where could I upload those testout.wav´s? I listened them and both sound the same.

I can´t figure this out.. Is it those last 3 filters? Or the amount of filters?

Another interesting thing is that even with that working file I only barely get any audio from right channel while lef channel works just fine.


This is one of the files I have created some time ago with rew. This file works just like it is supposed to.
Spoiler
Filter Settings file

Room EQ V5,00
Dated: 16.9.2013 13:05:32

Notes:

Equaliser: Generic
syys 16 13:02:41
Filter 1: OFF PK Fc 5014 Hz Gain -10,7 dB Q 3,45
Filter 2: OFF PK Fc 47,9 Hz Gain -22,6 dB Q 8,00
Filter 3: OFF PK Fc 63,4 Hz Gain -12,9 dB Q 7,25
Filter 4: OFF PK Fc 38,5 Hz Gain -6,0 dB Q 10,00
Filter 5: ON PK Fc 20 Hz Gain 6,0 dB Q 1,00
Filter 6: ON PK Fc 15 Hz Gain 6,0 dB Q 1,00
 
#180 ·
Where could I upload those testout.wav´s? I listened them and both sound the same.
I meant that you look at these files by opening them in an audio editor like Audacity. If there was a malfunction in E-APO that causes the output of silence then you would see that in the audio editor. But, as you say that they sound equal, the processing is likely working correctly, no need to upload the files.

I can´t figure this out.. Is it those last 3 filters? Or the amount of filters?

Another interesting thing is that even with that working file I only barely get any audio from right channel while lef channel works just fine.
The underlying problem is not the amount of filters or how they are configured, as the Benchmark test shows. As your configuration doesn't contain any "Channel" commands, the audio from both channels should be altered in the same way.

All this makes me think that there is a problem in your audio setup that is somehow triggered by the changes that E-APO does to the audio. Could you please add the line
Code:
Preamp: -6 dB
to the configuration file that causes problems and see if you hear a change? You could even experiment with the amount of decibels for the preamp.



Unfortunately my sound card drivers don't have a delay function in their driver setup.
[...]
I have been getting my delay by using FFDShow's audio setup but it doesn't affect all sounds like E-APO does.
[...]
Ultimately if multiple delays could be applied within adjustable frequency ranges then I mite just part with some cash for this great program. That way I could adjust the timing of the frequencies that go to the tweeters/woofers/subwoofers.

Phase correction would just be an added bonus.
Unfortunately, I didn't have much time to work on the next version of E-APO recently, but I will get back to it soon. This next version will contain a Delay command and it will also be possible to copy audio to additional "virtual" channels so that you can apply processing to them and mix them back later.

So you might not be able to directly adjust the delay of frequency ranges but with some lines in the config file you can split the audio into virtual channels for specific frequency ranges, apply the delay to them and then add them together to form the output. You can ask me for an example of that when the next version is released if you want.

Phase correction will not be possible yet, however.
 
#183 · (Edited)
just a word to say EqAPO has a new version (0.9)
i will test the new function copy to send REW signal to each channel of my 5.1 system (for now, i used VBcable).
thanks again for your job

edit:
Copy: RL=0. L=0. R=0. C=0. RR=L SUB=0.
allow to test rear right with REW for example. test today and it's OK. (but i don't know the influence in the measurement)

by the way; if i want to test all the channel together, is the command
Copy: RL=0.2*L L=0.2*L R=0.2*L C=0.2*L RR=0.2*L SUB=0.
the right command ?
 
#184 ·
Sorry, the email notification seems not to work for edits in existing messages, so I did not notice your question. Better post a new message the next time.

by the way; if i want to test all the channel together, is the command
Copy: RL=0.2*L L=0.2*L R=0.2*L C=0.2*L RR=0.2*L SUB=0.
the right command ?
Yes, this will copy the audio from the left channel (reduced to 20 % of the original volume) to all channels but the subwoofer channel. The subwoofer channel will be muted and any audio that was previously on the other channels will be replaced by the audio from the left channel.
 
#185 ·
Hi, firstly thanks for this great piece of software! I have currently installed it and verified that filters apply correctly (and preamp settings affect system output) so I know that all is well on that front.

However, I am having some trouble measuring my subwoofer response in REW after applying filters in Eq APO. The issue is that I can't seem to get correct output to only my subwoofer for sweeps when using Java audio in REW.

I have my receiver set to 200Hz crossover, and Fronts, Center and Surrounds to "Small". When I do a measurement sweep from 15Hz - 200Hz in REW, the subwoofer does get some signal, but so do my Fronts. The overall SPL is much lower than when I use ASIO4ALL to do a measurement using Channel 4 (subwoofer) only. Because of this issue, I can't seem to get a proper sub response using the Java sound driver and I can't determine whether the filters are working correctly to even out my subwoofer response.

Does anyone have any suggestions on how I can go about using REW to make measurements of my sub response?
 
#186 ·
if i can answer,
if you wish to test only your sub, you have to use in config.txt
COPY: RL=0. L=0. R=0. C=0. RR=0. SUB=L
in this case REW plays it sweep to Left channel and EQApo root it to sub

if you say RL=0. L=0. R=0. C=L RR=0. SUB=0. for example eqAPO transmit left channel to center and as your HP are define as small, part of the sound are root by the amp. to sub
=> as i suppose you don't use copy, REW transmit your signal to left (and/or ? right) channel and that's why you can listen part of it to fronts and part to sub (because the small definition of your fronts)

i use the method to create a group of filters by channel, then to evaluate the effects of the filters. After the creation and test, i suppress the copy line to use filters in "real life"
 
#187 ·
Thanks xxxx5! Jonas pointed me to the same idea on his Sourforge discussion thread where I had also posted. I tried this approach and it worked like a charm! The only extra thing I had to do was I had to disable mic noise cancellation and other post processing in the mic driver settings in windows (I am using a cheap mic at the moment). ASIO mode for mics automatically grabs raw data but in Java mode, this post processing was filtering out the low frequencies and giving me weird results.

This is what I have been able to achieve after EQing my sub :):

3 Seating positions:


Position Averaged response (+/- 3dB over 19 - 84 Hz):
 
#189 ·
Hey,

first of all, thank you for this great software.

Recently I stumpeld across "LoCo: localisation correction" by frank_l. It is done as follows
frank_l said:
The signals L and R of the left and right stereo channel are transformed in sum M = L+R and difference S = L-R. Then I apply a filter to the S channel such that the waves in this graph are transformed to straight lines which meet the waves in the values for 1000Hz. With the filtered signal S' the new left and right channels are reconstructed as L' = (M+S')/2 and R' = (M-S')/2.

I wonder if it would be possible to translate the calculations to EQ APO? I'm stuck at that:

Code:
Filter Settings file
Eval: M = L+R; S = L-R

What should I put here? I want to assign the filters to S which results in S'
Filter  1: ON  PK       Fc       400 Hz  Gain   2 dB  Q  0,4
Filter  2: ON  PK       Fc      4000Hz  Gain  -2 dB  Q  0,4

Eval: L' = (M+S')/2
Eval: R' = (M-S')/2

Copy: L'=1 R'=2
How could I tell EQ APO that S' = S + Filter 1 + Filter 2?
 
#190 ·
for me the answer to your question is :
....
Copy: S'=S
Channel: S'
filter 1: ...
filter 2: ...
.....

but i am not sure that you can make operation on channels except adding then ( R=(M-S)/2 may be forbidden)
the best way is trying using benchmark (in same dir as equapo)
 
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