ethernode
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- Dec 27, 2022
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Hello everyone; i'm relatively new to this, and struggled a bit to setup, so i thought i would share what i learnt.
To put things into context, i had the opportunity to buy Kef LS50 (1st gen) for a very low price (380€) and i own a used MiniDSP 2x4 (non-HD, the 48 Khz one, which i bought used for ~70€) and an SVS-SB1000 sub. I wanted to implement the optimized anechoic EQ settings that @Maiky76 kindly provided here, but it wasn't that easy as a beginner.
The goal for this tutorial is to help newbies like myself deploy optimized EQ filters sometimes found on this forum (like the one below) on this MiniDSP platform.
As reminder (this is common knowledge, but that wasn't clear to me so i'll repeat it for beginners like me), we want to apply these mostly for correcting frequency response above the schroeder frequency where the perceived sound is mostly dictated by the speaker behaviour (below this frequency, the room is mostly affecting sound so there's little one can do without measuring your own room). The filters above have been computed based on frequency response measurements achieved in an anechoic chamber or alternative, room-independant measurements (like the Klippel system), with an algorithm that targets to maximize the Harman speaker preference score [reference needed].
It was not that straightforward to apply the filters above, notably because
- MiniDSP seems to have released their 2x4 advanced "plugin" relatively late, so most information regarding the use of the MiniDSP 2x4 is kind of outdated (e.g. the REW UI assumes 6 BQ and not 5, tutorials are for other plugins, etc ...)
- the MiniDSP 2x4 has 5 band PEQs, not 9, so a splitting strategy must be defined
- the crossover parameters (HighPass filters 1 and 2) described above need to be input as biquads (advanced mode)
- although i already did auto-EQ with REW, i did not know how to convert manual/custom PEQ parameters in REW into biquads usable into the MiniDSP
The MiniDSP 2x4 plugin specsheet states that there is one 5-band PEQs available per input and output channel (5 biquads each), as well as 4 LPF/HPF block that consists of 8 PEQs (confirmed by MiniDSP support).
Based on the above
- i applied the preamp gain in the first blocks
- i routed Left into output 1, routed RIght into output 3, output 2 gets L+R summed signal for the sub
- i placed filters 5-9 into the the downstream 5-band PEQ blocks, and filters 1-4 into the LPF+HPF block
This should leave 4 biquads after the matrix and 5 before (full band) for room correction. Below is the setup:
To generate the biquads using REW, i followed the following steps:
1. Click "EQ"
2. Select miniDSP eq type, click "EQ Filters"
3. Insert the high frequency components (only 5)
4. Export coefficients to file
5. Do the same for the crossover block, but the exported file should be completed with 2 disabled biquads (the MiniDSP expects exactly 8 biquads), which i did by copy-pasting (the files are available as attachments)
6. Spin up the MiniDSP plugin UI, configure the routing
7. Select the crossover block, click "Advanced", copy-paste the xo_8bq.txt file contents, hit "Process" -- the UI does not offer an "Import REW file" button here -- which is also why i had to fiddle with it to reach 8 biquads; do this also on the crossover of Output 3
8. Move on to the PEQ - output 1 block, click "Import REW File", import "after_xo_bq.txt"
9. Click "Copy to output 3"
10. Apply a 24 dB/octobe Low Pass LR filter on Output 2 (sub)
11. Apply the -0,9 dB gain on the Input Gain block
I included the full XML settings file for convenience.
Things i did not understand:
- could i have used any other 48 Khz Equalizer in the REW window (to avoid having to split the biquads in two steps) ? Or will REW possibly apply format tweaks on the export ? Why is REW limiting MiniDSP EQ to 6 band only ?
- not sure how to configure the low pass for the sub to match the modified high pass
Feel free to feedback if you know better ways to achieve the above ! I hope this helps someone.
To put things into context, i had the opportunity to buy Kef LS50 (1st gen) for a very low price (380€) and i own a used MiniDSP 2x4 (non-HD, the 48 Khz one, which i bought used for ~70€) and an SVS-SB1000 sub. I wanted to implement the optimized anechoic EQ settings that @Maiky76 kindly provided here, but it wasn't that easy as a beginner.
The goal for this tutorial is to help newbies like myself deploy optimized EQ filters sometimes found on this forum (like the one below) on this MiniDSP platform.
Code:
Preamp: -0.9 dB
Filter 1: ON HighPass Fc 75.31, 0.00, 1.48
Filter 2: ON HighPass Fc 90.38, 0.00, 0.74
Filter 3: ON PK Fc 152.65, -3.17, 0.78
Filter 4: ON PK Fc 550.00, 1.40, 3.72
Filter 5: ON PK Fc 830.00, -2.40, 1.83
Filter 6: ON PK Fc 1224.00, -1.34, 9.45
Filter 7: ON PK Fc 1609.00, 2.11, 2.65
Filter 8: ON PK Fc 2764.00, -2.80, 1.35
Filter 9: ON PK Fc 4747.00, -3.40, 3.00As reminder (this is common knowledge, but that wasn't clear to me so i'll repeat it for beginners like me), we want to apply these mostly for correcting frequency response above the schroeder frequency where the perceived sound is mostly dictated by the speaker behaviour (below this frequency, the room is mostly affecting sound so there's little one can do without measuring your own room). The filters above have been computed based on frequency response measurements achieved in an anechoic chamber or alternative, room-independant measurements (like the Klippel system), with an algorithm that targets to maximize the Harman speaker preference score [reference needed].
It was not that straightforward to apply the filters above, notably because
- MiniDSP seems to have released their 2x4 advanced "plugin" relatively late, so most information regarding the use of the MiniDSP 2x4 is kind of outdated (e.g. the REW UI assumes 6 BQ and not 5, tutorials are for other plugins, etc ...)
- the MiniDSP 2x4 has 5 band PEQs, not 9, so a splitting strategy must be defined
- the crossover parameters (HighPass filters 1 and 2) described above need to be input as biquads (advanced mode)
- although i already did auto-EQ with REW, i did not know how to convert manual/custom PEQ parameters in REW into biquads usable into the MiniDSP
The MiniDSP 2x4 plugin specsheet states that there is one 5-band PEQs available per input and output channel (5 biquads each), as well as 4 LPF/HPF block that consists of 8 PEQs (confirmed by MiniDSP support).
Based on the above
- i applied the preamp gain in the first blocks
- i routed Left into output 1, routed RIght into output 3, output 2 gets L+R summed signal for the sub
- i placed filters 5-9 into the the downstream 5-band PEQ blocks, and filters 1-4 into the LPF+HPF block
This should leave 4 biquads after the matrix and 5 before (full band) for room correction. Below is the setup:
To generate the biquads using REW, i followed the following steps:
1. Click "EQ"
2. Select miniDSP eq type, click "EQ Filters"
3. Insert the high frequency components (only 5)
4. Export coefficients to file
5. Do the same for the crossover block, but the exported file should be completed with 2 disabled biquads (the MiniDSP expects exactly 8 biquads), which i did by copy-pasting (the files are available as attachments)
6. Spin up the MiniDSP plugin UI, configure the routing
7. Select the crossover block, click "Advanced", copy-paste the xo_8bq.txt file contents, hit "Process" -- the UI does not offer an "Import REW file" button here -- which is also why i had to fiddle with it to reach 8 biquads; do this also on the crossover of Output 3
8. Move on to the PEQ - output 1 block, click "Import REW File", import "after_xo_bq.txt"
9. Click "Copy to output 3"
10. Apply a 24 dB/octobe Low Pass LR filter on Output 2 (sub)
11. Apply the -0,9 dB gain on the Input Gain block
I included the full XML settings file for convenience.
Things i did not understand:
- could i have used any other 48 Khz Equalizer in the REW window (to avoid having to split the biquads in two steps) ? Or will REW possibly apply format tweaks on the export ? Why is REW limiting MiniDSP EQ to 6 band only ?
- not sure how to configure the low pass for the sub to match the modified high pass
Feel free to feedback if you know better ways to achieve the above ! I hope this helps someone.
Last edited:
