REW and EQAPO for 5.1

[bebealex]

Hi,

I tried finding the answers but could not get anything, please feel free to tell me if I missed it.

I'm trying to figure out if I'd need an AVR that would support great room correction of if REW and EQAPO could do fine. I currently have a no-name 20 years old exterior speaker as a center and some old Yamahas as stereo and surrounds. AVR is HTR-2064. Mic is UMIK-1 on boom stand. Center is about to change for a Paradigm 500C. Source is always a computer.

I'm trying to understand the workflow for using REW. As far as I could find when measuring with REW it play one sound on all speakers.

I found how to play individual channels using ASIO but all the tutorias I find use a single sweep on all speakers.. But when using any other output than ASIO only the FR and FL are used.

The method in the video worked wonders for my stereo system, but am I supposed to be able to use it for anything more than L+R ? I can only select more channels when outputting trough ASIO but only one at a time.. How does it translate to EQAPO ??

I fail to understand how it could correct for my different center channel when it plays only one sound on all speakers. Would EQ-ing the individual speakers trough the AVR be the first option before using rew to make a filter ? But then the problem arrises.. I can only play on two speakers at a time.

I'm truly lost and I greatly appreciate some help understanding what to do.

 

[Erici]

Keith has created created an excellent guide. Here is the link:

Taking and Interpreting Measurements with REW (FREE eBook)

A few years ago, Amir wrote Room Measurement Tutorial for Dummies Part 1 and Part 2. The third part has never materialized despite many requests. In the meantime, there is a clear need for clear guide on how to take room measurements because we are seeing more and more people take and post their...

www.audiosciencereview.com

 

[bebealex]

Hi Erici,

Thanks for the reply.

He does talk in absolute details on measurements but unless I missed something, Keith is discussing about room improvements that could be made reading the . measurements and / or seems to indicate that the reader will eq his speakers on his own.

I do not see any part about importing curves in EQAPO, or mention of curves per speakers in EQAPO, or mention of manually Eq-ing different speakers before EQAPO-ing them.

Which is what I was wondering about.

 

[whazzup]

Hi Erici,

Thanks for the reply.

He does talk in absolute details on measurements but unless I missed something, Keith is discussing about room improvements that could be made reading the . measurements and / or seems to indicate that the reader will eq his speakers on his own.

I do not see any part about importing curves in EQAPO, or mention of curves per speakers in EQAPO, or mention of manually Eq-ing different speakers before EQAPO-ing them.

Which is what I was wondering about.

Not sure if that's what you're asking about, but I got curious after reading your question and fiddled around with REW. What I found:

1. In REW's Preferences > Soundcard > Output, initially I couldn't get the different channels to show up as well, and will only see L, R, L+R, even though I have my sub connected to the LFE channel of my onboard soundcard. But then I selected all the other Output device available in the dropdown menu. And finally with the LG Ultragear+ selected, the various channels appeared. And amazingly, now when I switch back to my initial Realtek output, the various channels stay selectable. I tested, no problem with measuring each channel through my soundcard.

2. This video also talks about multi channel measurements, though it mentions ASIO as well. Still maybe can help:

 

[Keith_W]

REW can only send output to a maximum of two channels at a time. This is it's fundamental limitation. It is possible to measure multichannel systems, but you will need third party software (like EqAPO) and you will need quite a lot of brains to come up with workarounds. When I wanted to measure my multichannel speaker, it took me days to figure it out. Not hours ... days! Unfortunately, I can't help you with EqAPO since I don't use it - so I don't know what it's capabilities are.

Here are some software configs that you might want to use, depending on what you are measuring. I will assume that REW is able to see each individual DAC channel in your AVR.

1. To measure an individual speaker: REW --> DAC channel
2. To measure the effect of DSP on an individual speaker: REW --> EqAPO --> DAC channel
3. To time align one speaker to another at your listening position: REW --> DAC channel 1 (timing reference), AND REW --> DAC channel X (speaker under test)
4. To measure all 5.1 speakers together: REW --> EqAPO --> all DAC channels

I have greatly simplified it. It IS possible, and it IS free ... but getting multiple pieces of software to work together isn't easy. You find all sorts of weird compatibility issues ESPECIALLY for lesser known hardware, and you might have to use software cables like ASIO4ALL, Virtual Audio Cable (VAC), VB-Cable, etc. Just try it first and see how you go.

 

[WeekendWarrior]

Have you tried asking AI? I went from no knowledge to setting up an EQAPO configuration in very little time. As long as you remain sceptical rather than believing it without question, it may help. Good luck

 

[jeffaegrim]

Basically, REW can output 7.1 only in exclusive mode, which means it will bypass any filtering you have applied in EQAPO. The only way to measure corrected responses is by muting L or R and routing C/LFE/etc into the muted channel, then measuring it through REW in non-exclusive mode, where only two channels are available. It’s a pain in the ass.

I would absolutely LOVE to be corrected on this btw.

Have you tried asking AI? I went from no knowledge to setting up an EQAPO configuration in very little time. As long as you remain sceptical rather than believing it without question, it may help. Good luck

View attachment 545412

Did you mean to apply those high and low pass filters in pairs? They get stacked. I am assuming the center channel is a sub in your system, as otherwise the 80hz low pass filter for C doesn’t make much sense. I would also recommend installing Peace and using the channel routing matrix - the way you did the routing (by copying channels) will result in mismatched gain levels across channels and greatly reduced headroom. Been there.

 

[bebealex]

Not sure if that's what you're asking about, but I got curious after reading your question and fiddled around with REW. What I found:

1. In REW's Preferences > Soundcard > Output, initially I couldn't get the different channels to show up as well, and will only see L, R, L+R, even though I have my sub connected to the LFE channel of my onboard soundcard. But then I selected all the other Output device available in the dropdown menu. And finally with the LG Ultragear+ selected, the various channels appeared. And amazingly, now when I switch back to my initial Realtek output, the various channels stay selectable. I tested, no problem with measuring each channel through my soundcard.

Hum, my HDMI is going directly to the AVR then to the television, my only output is *the name of the television*.

Thanks for the video though, really appreciate it !

 

[bebealex]

REW can only send output to a maximum of two channels at a time. This is it's fundamental limitation. It is possible to measure multichannel systems, but you will need third party software (like EqAPO) and you will need quite a lot of brains to come up with workarounds. When I wanted to measure my multichannel speaker, it took me days to figure it out. Not hours ... days! Unfortunately, I can't help you with EqAPO since I don't use it - so I don't know what it's capabilities are.

Here are some software configs that you might want to use, depending on what you are measuring. I will assume that REW is able to see each individual DAC channel in your AVR.

1. To measure an individual speaker: REW --> DAC channel
2. To measure the effect of DSP on an individual speaker: REW --> EqAPO --> DAC channel
3. To time align one speaker to another at your listening position: REW --> DAC channel 1 (timing reference), AND REW --> DAC channel X (speaker under test)
4. To measure all 5.1 speakers together: REW --> EqAPO --> all DAC channels

I have greatly simplified it. It IS possible, and it IS free ... but getting multiple pieces of software to work together isn't easy. You find all sorts of weird compatibility issues ESPECIALLY for lesser known hardware, and you might have to use software cables like ASIO4ALL, Virtual Audio Cable (VAC), VB-Cable, etc. Just try it first and see how you go.

Hey thanks for the answer !

For the individual channels yes I can output individually trough ASIO. My center is really, really different from my other speakers so with your fourth point I think I'm gonna go :

1a. EQ each speaker directly via the AVR so they are as close as possible
OR
1b. Find how to configure EqAPO to eq each channel individually
OR
1C. REW the FR and FL then RR and RL, then center separately, then combine in EqAPO
2. Enjoy them as much as they deserve because movies are still fun when the surround helicopter is not note-perfect
3. Buy a Denon S/X and Evo Express

 

[bebealex]

Have you tried asking AI? I went from no knowledge to setting up an EQAPO configuration in very little time. As long as you remain sceptical rather than believing it without question, it may help. Good luck

It goes against my religion unfortunately but I'll for sure give it a go on my own. Just reading how it implements L and R seems to indicate how to send to the other channels. Just have to EQ them separately and copy paste in one big txt file.
Thanks !

 

[bebealex]

Basically, REW can output 7.1 only in exclusive mode, which means it will bypass any filtering you have applied in EQAPO. The only way to measure corrected responses is by muting L or R and routing C/LFE/etc into the muted channel, then measuring it through REW in non-exclusive mode, where only two channels are available. It’s a pain in the ass.

I would absolutely LOVE to be corrected on this btw.


Did you mean to apply those high and low pass filters in pairs? They get stacked. I am assuming the center channel is a sub in your system, as otherwise the 80hz low pass filter for C doesn’t make much sense. I would also recommend installing Peace and using the channel routing matrix - the way you did the routing (by copying channels) will result in mismatched gain levels across channels and greatly reduced headroom. Been there.

I do not understand what would mean by my center channel being a subwoofer, it's a center channel ?

If I can find a way to make EQAPO apply different filters to each channels I think I'll be golden

 

[Keith_W]

1a. EQ each speaker directly via the AVR so they are as close as possible

Since you have multiple dissimilar speakers that you are trying to get to play together, I would EQ each speaker individually as you are proposing. But you have to be VERY CAREFUL when you take those measurements. Measurements for DSP are a complete different kettle of fish to room measurements, it is much more difficult. You do not want to be correcting artefacts, and you need to make absolutely sure that you have the minimum-phase response before you attempt to invert it. And not some kind of measurement artefact that doesn't exist.

 

[bebealex]

Since you have multiple dissimilar speakers that you are trying to get to play together, I would EQ each speaker individually as you are proposing. But you have to be VERY CAREFUL when you take those measurements. Measurements for DSP are a complete different kettle of fish to room measurements, it is much more difficult. You do not want to be correcting artefacts, and you need to make absolutely sure that you have the minimum-phase response before you attempt to invert it. And not some kind of measurement artefact that doesn't exist.

I 100% agree.

In the end I must admit it's not for critical listening. Having a good, balanced center is 80% of movies and for music I can easily switch and EQ the two front speakers.

It is understandable that REW does not measure per speaker when no one is going to have two different left and right.

I say again, thanks for the answers. The brainstorming was really helpful.