First of all thanks to the developer for this great and straight forward software!
I have a question related to downmix process. I'm actually having a 4.0 speaker system, where the two front channels "include" a subwoofer (i.e. Focal Little Bird 2.1 Pack where 2.1 is not properly correct...). On such basis, to downmix a 5.1 audio to my 4.0 setup, I guess it is necessary to equally split both C and SUB channels on the L and R ones (LR and RR would remain untouched). Can you please indicate me which of these two equation sets is correct?
L = L + 0.5*C + 0.5*SUB
R = R + 0.5*C + 0.5*SUB
or
L = L + 0.7071*C + 0.7071*SUB
R = R + 0.7071*C + 0.7071*SUB
where the number 0.7071 derives from the conversion in linear of -3dB (that is "half" channel power).
Another question: would it be possible to redirect just some frequencies over the the front channels? For example, if my rear speakers frequency responses begin at 120 Hz, how can I redirect lower frequencies (< 120 Hz) over the front ones that include the subwoofer?
You might also want to high pass filter the channels RL and RR at 120 Hz to make sure that the sum of the frequency responses does not have a peak around the crossover frequency
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
I took a look around and found this discussion that I think can be useful to understand the first point reported in my initial post. So it seems that the correct factor to split C over L and R is 0.7071.
Having said that, I saw that Equalizer APO can also manage equations using directly the dB format in the coefficients. From such perspective, do the following equations:
Copy L=L+0.7071*C
Copy L=L+-3dB*C
produce the same result? How are they managed (and which are the differences) inside Equalizer APO?
Have a nice day!
Last edit: Alessandro 2016-04-11
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Thank you for sharing that link, it is interesting that acoustics work a bit different.
The dB variant is converted to linear during initialization, so during the actual processing there is no difference (apart from the rounding in 0.7071):
Can anyone help me, im trying to make the same thing on my system, but as a begginer there are somethings I don't understand.
The way i see i shoul just paste
L = L + 0.7071C + 0.7071SUB
R = R + 0.7071C + 0.7071SUB
On the config.txt APO created for my speaker, is that correct?
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Can anyone help me, im trying to make the same thing on my system, but as a begginer there are somethings I don't understand.
The way i see i shoul just paste
L = L + 0.7071C + 0.7071SUB
R = R + 0.7071C + 0.7071SUB
On the config.txt APO created for my speaker, is that correct?
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
That will place half of center into L, half into R, and same for the sub. (FYI the * is not showing correctly but turning the text between them into italics.)
You should probably add a "Preamp: -6dB" at the beginning to provide more headroom since you are adding to channels, to prevent clipping.
It's helpful to have the Equalizer APO log file open (it's at C:\Windows\ServiceProfiles\LocalService\AppData\Local\Temp\EqualizerAPO.log on Windows 10) when writing custom config.txt files so you can catch any errors.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hi All,
First of all thanks to the developer for this great and straight forward software!
I have a question related to downmix process. I'm actually having a 4.0 speaker system, where the two front channels "include" a subwoofer (i.e. Focal Little Bird 2.1 Pack where 2.1 is not properly correct...). On such basis, to downmix a 5.1 audio to my 4.0 setup, I guess it is necessary to equally split both C and SUB channels on the L and R ones (LR and RR would remain untouched). Can you please indicate me which of these two equation sets is correct?
or
where the number 0.7071 derives from the conversion in linear of -3dB (that is "half" channel power).
Another question: would it be possible to redirect just some frequencies over the the front channels? For example, if my rear speakers frequency responses begin at 120 Hz, how can I redirect lower frequencies (< 120 Hz) over the front ones that include the subwoofer?
Thanks in advance for any help!
Last edit: Alessandro 2016-04-07
The first equation set seems to be correct for me as for amplitudes -6 dB is about the half. But hopefully someone else can explain it better.
To redirect the lower frequencies of channels, you need to use virtual channels:
You might also want to high pass filter the channels RL and RR at 120 Hz to make sure that the sum of the frequency responses does not have a peak around the crossover frequency
Thanks Jonas for your answer.
I took a look around and found this discussion that I think can be useful to understand the first point reported in my initial post. So it seems that the correct factor to split C over L and R is 0.7071.
Having said that, I saw that Equalizer APO can also manage equations using directly the dB format in the coefficients. From such perspective, do the following equations:
produce the same result? How are they managed (and which are the differences) inside Equalizer APO?
Have a nice day!
Last edit: Alessandro 2016-04-11
Thank you for sharing that link, it is interesting that acoustics work a bit different.
The dB variant is converted to linear during initialization, so during the actual processing there is no difference (apart from the rounding in 0.7071):
Great! Everything is now clear!
Thanks a lot Jonas for your great work!
Can anyone help me, im trying to make the same thing on my system, but as a begginer there are somethings I don't understand.
The way i see i shoul just paste
L = L + 0.7071C + 0.7071SUB
R = R + 0.7071C + 0.7071SUB
On the config.txt APO created for my speaker, is that correct?
Can anyone help me, im trying to make the same thing on my system, but as a begginer there are somethings I don't understand.
The way i see i shoul just paste
On the config.txt APO created for my speaker, is that correct?
That will place half of center into L, half into R, and same for the sub. (FYI the * is not showing correctly but turning the text between them into italics.)
You should probably add a "Preamp: -6dB" at the beginning to provide more headroom since you are adding to channels, to prevent clipping.
It's helpful to have the Equalizer APO log file open (it's at C:\Windows\ServiceProfiles\LocalService\AppData\Local\Temp\EqualizerAPO.log on Windows 10) when writing custom config.txt files so you can catch any errors.