TOPIC:

I am running a Danley DTS-10 Subwoofer in my HT. I currently use a Behringer Feedback Destroyer as a Parametric EQ, I use 4 or five filters to tame the frequency response in my room.

I can not create a high pass with the Behringer. Danley specs a 15 Hz HP @ 24 dB/Butterworth.
This will be a set and forget setup. Is the Mini DSP capable of doing this? Can someone guide me through setting it up?

Hello,

You can indeed place a 15Hz HP but it requires a bit of programming... you will need to use the biquad programming feature of the advanced plug-in. www.minidsp.com/applications/advanced-biquad-programming

Have a look at this spreadsheet for the calculation: www.minidsp.com/applications/linkwitz-transform

Maybe in the future, we'll add that capabilities straight into the filtering section. For the time being, it's custom biquad.

Hope this makes sense,

It does make sense and I have run across the excellent spread sheet that was created to build biquad filters.

I have very limited knowledge of these types of filters. I guess I am looking for someone to guide me as to what I need to plug into the spreadsheet to generate a 15 Hz HP @ 24 dB/Butterworth.
The Parametric EQ portion I can handle.

I will not be using this devise to do complex cross overs. I want a one time set and forget HP and EQ for my dedicated theater. I realize it is a very powerful devise, at this price point it is economic to do what I am suggesting. I am sure there are lots of other DIY guys with enough knowledge to be dangerous but not enough to dig into this deeply. Adding to the front end to make it easy for inexperienced people to do a bit more will likely increase sales by quite a bit.

Thanks for your reply.

24 dB/oct BW means it's a 4th order filter. You can construct this with 2 second order filters with a Q of 0.541 and a Q of 1.31 (look here ). Use the spreadsheet to calculate the biquads.

HP 15Hz Q=0.541:
a0 1
a1 1.996373346737630
a2 -0.996377195067089
b0 0.998187635451180
b1 -1.996375270902360
b2 0.998187635451180

HP 15Hz Q=1.31:
a0 1
a1 1.998498419515570
a2 -0.998502271941445
b0 0.999250172864254
b1 -1.998500345728510
b2 0.999250172864254


In the image you can see how the 4th order filter (white) is constructed from the 2 second order filters (red and brown).

Cut and paste the numbers in the format used by the plugin and you're done:

biquad1,
b0=0.998187635451180,
b1=-1.996375270902360,
b2=0.998187635451180,
a1=1.996373346737630,
a2=-0.996377195067089,
biquad2,
b0=0.999250172864254,
b1=-1.998500345728510,
b2=0.999250172864254,
a1=1.998498419515570,
a2=-0.998502271941445,
biquad3,
b0=1,
b1=0,
b2=0,
a1=0,
a2=0,
biquad4,
b0=1,
b1=0,
b2=0,
a1=0,
a2=0,
biquad5,
b0=1,
b1=0,
b2=0,
a1=0,
a2=0,
biquad6,
b0=1,
b1=0,
b2=0,
a1=0,
a2=0,
biquad7,
b0=1,
b1=0,
b2=0,
a1=0,
a2=0,
biquad8,
b0=1,
b1=0,
b2=0,
a1=0,
a2=0

That is awesome, thanks.