Home› BSS User Forum › BSS Archive Threads› Discussion› Omnidrive/Minidrive

Fillter Usage- out of filters? How to count?

Kip ConnerKip Conner Posts: 5
in Omnidrive/Minidrive
I have a 336 (not a 336T- although I'm about to upload the newer fiirmware) and I'm running out of filters.

According to the manual you get X number of filters per band. Is this on any program loaded or is this across the entire unit.

I'm writing a new program and I ran out of filter before I got to the highs. I would understand if I was using a ton- but I used 3 on the lows and 4 on the mids- leaving me one available. I am using LR24 slopes.

On that note, am I to understand that use a filter for each order of crossover point (x 2 because the outputs are linked for a Stereo 3way)?

So before I even get to the EQ filters on a 3 way Stereo with LR24 filters, How many have I used?

According to my math: 24 filters

Is this correct?

So, by adding 4 EQ points to Outputs 1-2 and 3 Points to Outputs 3-4, I have used 14 more filters?

Now i have used 38?

Can I save filters by setting the XO Mode to Both, instead of Edge?

Comments

  • rob birchrob birch Posts: 106
    As per page 46 of the user manual

    The crossover filters and EQs share DSP resources between two DSP chips. There are certain assignment constraints, the table below summarizes how the resources are allocated. (sorry it did not copy across)
    The EQ for outputs 3-6 may come from either DSP 1 or DSP 2, but DSP 2 filters are used first, until all DSP 2 resources are allocated.
    Summing this up in words:
    􏰀 There are 18 filters in DSP 1, and 20 in DSP 2.
    􏰀 All of the crossover filters for Outputs 1 & 2 come from DSP 1.
    􏰀 All of the crossover filters for Outputs 3-6 come from DSP 2.
    􏰀 All of the Input EQ comes from DSP 1.
    􏰀 All of the Output EQ for Outputs 1 & 2 comes from DSP 1.
    􏰀 Output EQ for Outputs 3-6 may come from either DSP.
    Other notes:
    􏰀 12dB/Octave crossovers use 1 filter per edge, except Linkwitz-Riley that uses 2.
    􏰀 18, 24 & 36dB/Octave crossovers use 2 filters per edge.
    􏰀 48 & 52dB/Octave crossovers use 4 filters per edge.
    􏰀 Stereo EQs use 2 filters each.

    For example, a stereo 3 way 12dB/octave crossover would use DSP resources as follows:
    􏰀 4 filters are used in DSP 1 for Output 1 & 2 crossovers high edge crossovers. (2 per 12dB/
    Octave Slope)
    􏰀 12 filters used in DSP 2 for Output 3-6 crossovers. (1 per 12dB/Octave Slope)
    􏰀 There is a total of (18-4)= 14 filters left in DSP 1 for either Input EQ or Outputs 1 & 2 EQ.
    􏰀 There is a total of (20-12)= 8 filters left in DSP 2 for any Output EQ.


    So as per your example of LR 24Db per octave slopes.
    Out 1 = LR24db Low filter and LR24db High Filter = 4 filters DSP 1
    Out 2 = LR24db Low filter and LR24db High Filter = 4 filters DSP 1
    8 used 10 filters available

    Out 3 = LR24db Low filter and LR24db High Filter = 4 filters DSP 2
    Out 4 = LR24db Low filter and LR24db High Filter = 4 filters DSP 2
    Out 5 = LR24db Low filter and OUT High Filter = 2 filters DSP 2
    Out 6 = LR24db Low filter and OUT High Filter = 2 filters DSP 2
    12 used 8 filters available

    So 18 filters are available. If you apply these to stereo outs they count for 2 so 9 EQs can be used over all the outputs

    Normally you could use BUt 12DB filters around the HF and MF which would save a further 4 filters.

    If you use London Architect you can place a 336 in the main window and it will show you how many filters are remaining for the current configuration.

    Hope this helps.

    Kind regards

    Rob
This discussion has been closed.