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Thread: Project M2 DIY Thread

  1. #601
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    QSC QSYS now supports 16,384 taps on their FIR filter as of version 7.2.1

    Just an update to those of us that are using QSYS for the DSP on an M2 (or other speakers). As of software version 7.2.1, issued today (12/12/18), it now supports 16,384 taps on the FIR filters so pos' FIR filter solution should be able to be incorporated into designs without the need of extra PEQ filters on the LF section.

    Previously, in 7.2.0, QSC added FIR filter capability in their amplifiers. The current tap limitation (by device) is:


    • DPA-Q/CXD-Q 4-channel amplifiers: 1,024 taps
    • DPA-QCXD-Q 8-channel amplifiers: 200 taps
    • DataPort cards/amplifiers: 200 taps
    • Core: 16,384 taps

    So, for the M2, you'll need to use the CORE's FIR filters.

    -Steve

  2. #602
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    Quote Originally Posted by sguttag View Post
    Just an update to those of us that are using QSYS for the DSP on an M2 (or other speakers). As of software version 7.2.1, issued today (12/12/18), it now supports 16,384 taps on the FIR filters so pos' FIR filter solution should be able to be incorporated into designs without the need of extra PEQ filters on the LF section.

    Previously, in 7.2.0, QSC added FIR filter capability in their amplifiers. The current tap limitation (by device) is:


    • DPA-Q/CXD-Q 4-channel amplifiers: 1,024 taps
    • DPA-QCXD-Q 8-channel amplifiers: 200 taps
    • DataPort cards/amplifiers: 200 taps
    • Core: 16,384 taps

    So, for the M2, you'll need to use the CORE's FIR filters.

    -Steve
    16,384 taps, That's a huge amount to have on tap, gotta wonder though what its going to do to the utilization especially on the smaller 110f/c units.

  3. #603
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    Quote Originally Posted by lesliew View Post
    16,384 taps, that's a huge amount to have on tap, gotta wonder though what its going to do to the utilization especially on the smaller 110f/c units.
    Kaboom! That is a single FIR component with 16,384 taps.

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    Fortunately, you can set the number of taps so if you want to use pos' FIR filter, then drop it down to 6144. Only 30% to put four of those, which is sufficient for "stereo."
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    Note, I haven't loaded anything into those filters...just checking on the raw space they will consume.

    I also noted that the "c" version of the 110 and 510 consumed less resources on the FIR filters than their "i" counterparts. I suspect us giving up 4 AECs freed up resources for other, non-telephony, things.

  4. #604
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    Nice! I guess this is FFT convolution then.
    6144 taps is a bare minimum for the LF part. The HF part requires much less
    Given this is FFT convolution guessing buffering delays can be non trivial, so it might be good to choose the same amount of taps for LF and HF.

  5. #605
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    QSC QSYS FIR filters beyond 4096 taps

    Quote Originally Posted by pos View Post
    Nice! I guess this is FFT convolution then.
    6144 taps is a bare minimum for the LF part. The HF part requires much less
    Given this is FFT convolution guessing buffering delays can be non trivial, so it might be good to choose the same amount of taps for LF and HF.
    So I decided to play a bit. This is the DSP resources consumed by putting just one set of filters in (one high and one low). I then put in a pair of each and it did not consume more DSP resources. So I presume, once you start putting in a FIR filter, it blocks out DSP resources for them and doesn't tick up more until you reach some threshold.

    Anyway, here is the interesting bit. If you do the JBL M2 crossover with 6144 taps on both HF and LF, using the smallest core, the 110f, you consume 30% of your resources (note, an empty design starts out at 2%).

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    If you decide to be clever and use a 4096 tap HF filter and keep the 6144 tap for the low, you pay a penalty:

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    So pick a tap size and stick with it!

  6. #606
    Senior Member pos's Avatar
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    Quote Originally Posted by pos View Post
    A question for those how 3D-printed their ports based on the STL files.
    What printing parameters did have success with? (material, infill, layer height, thickness, etc.)
    Anyone?

  7. #607
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    Quote Originally Posted by pos View Post
    A question for those how 3D-printed their ports based on the STL files.
    What printing parameters did have success with? (material, infill, layer height, thickness, etc.)
    I've been using cura to produce the 3D printable files.

    Parameters

    PLA
    Fine - layer height 0.1mm
    100% infill

    I did find that if I used anything but 100% infill the wall of the port would crack after a few days because its relatively thin.

    Even if you have a heated bed I would definitely recommend using build plate adhesion to prevent warping since the model will be printing for a long time. I also flipped JBL_M2_Port_Front 180 degrees so that the flat section was on the bed.

  8. #608
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    Thank you Leslie, that is very helpful!

  9. #609
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    Hi,
    Great for the 3D printout question and answer, seems to be the question of the week ;-)
    Also, do you think we can just ask a 3D printshop to print the STL from cyrilio?

    Also, for the D2430, is the 4x screw size to fix it on the horn something like "1/4-20 unc"?

    Thanks

  10. #610
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    Quote Originally Posted by rodec View Post
    Hi,
    Great for the 3D printout question and answer, seems to be the question of the week ;-)
    Also, do you think we can just ask a 3D printshop to print the STL from cyrilio?

    Also, for the D2430, is the 4x screw size to fix it on the horn something like "1/4-20 unc"?

    Thanks
    The horn does not have tapped holes. You are screwing into plastic. As such, they need to be aggressive self-tappers. I used a 10-14 x 1.5" screw. Link to the Amazon item:

    https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

    You can see them in my post #559

    http://www.audioheritage.org/vbullet...l=1#post416556

    I also used a flat washer for every screw and fender washers when attaching the horn to the cabinet. You'll also notice that, on my version, we created a back door for the HF section so the driver would be accessible/serviceable. Also made assembly MUCH easier.

  11. #611
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    Thanks sguttag for dimension and link.

    For the 2430 driver itself, are the four holes 1/4-20 unc?

    I used as reference a POS' post about a 2450
    Name:  screw.jpg
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    and I've foung great the service door trick. So I changed a bit the back to make the full panel removeable:
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    But perhaps your original idea to have only a top part is better. I will see during the first proto construction what's the best.

  12. #612
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    Yes, the studs that attach the driver to the adapter plate are 1/4-20 x 1.5". Then Nylock nuts (nylon insert). I used blue Loctite when putting the studs into the driver. I also used flat washers though they are not called out in the exploded view of the speaker.

    As for creating an access panel. Our original design had the front panel (with drivers) as the removable one (see post 464 http://www.audioheritage.org/vbullet...l=1#post412790). So you could mount everything, then put the whole front plate into the speaker cabinet (just a 5-sided box, at that point). It had air leaks, among other things (and for most, would create cosmetic challenges, though we attached it from the sides/top/bottom, nothing visible from the front).

    In my application (the speakers are in a home-cinema that is being built more like a commercial cinema and reside in a baffle-wall), the only sensible access would be from the rear since removal of the screen and speaker would be required if any other side were used. The smaller the access, the easier it is to control air leaks and vibrations. As it is, our final version used two layers of 3/4" MDF so we are thicker on all sides except the driver plate itself. This really cut down on cabinet vibrations. Post #559 will give you a feel for how thick the cabinet is. Our rear door seemed to hit the balance we were looking for (and inspired by the HF access for the L250).

  13. #613
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    Bss file!

    I just got today Bss blu-100, I already have blu-50 which I`m using about two years in my M2 setup.
    I tried to make Bss tuning file from Jbl official site with audio architect based on readings on posts here in forum and entire wold wide web!!
    but it doesnt work like the original file! something is missing or I dont know how to workout.

    We all know that official Bss file is locked! but I need to add a Danley Dts-10 sub woofer along with M2, which has to be tuned too with parametric EQ, High-pass filter, delay...
    If anyone who has Bss piece, managed to unlock it or make it work no matter LA or AA please published here or send it to me over PM???

    Thanks

  14. #614
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    ports...

    morning,

    The screws step is over, thanks for the different sizes.

    I find the driver assembly design strange, as the driver does not center itself automatically with the metal plate,

    For ports, may you remind the length of the ports? to verify length is correct after having printed the STL.

    I am also looking for machining the front ports' wood plate, w/o a CNC. I am thinking about building a curved guide for router, but not so trivial and take time.
    So any experience and suggestion are welcome ;-)

  15. #615
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    Quote Originally Posted by Robh3606 View Post
    Could you please post the 2451SL on the horn no EQ?? Would love to see just how close the 476 Mg and the 2451SL measure on the same horn. My guess is close but would really like to see an actual measurement.

    Thanks Rob
    Did you ever see how close these were to each other?

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