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TOPIC: Re: Linkwitz transform

Re:Linkwitz transform 2 years 10 months ago #952

  • knuisje
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Ok, I did some measurements to test the correct implementation. This is a close range measurement of a closed box. I used these parameters in my spreadsheet to calculate the digital coefficients for the biquad LT equalizer:

f(0) = 87
Q(0) = 1.1
f(p) = 50
Q(p) = 0.707

In the graphs you can see the results.

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Re:Linkwitz transform 2 years 10 months ago #953

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And the measurements.

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Re:Linkwitz transform 2 years 10 months ago #954

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The biquad parameters.
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Re:Linkwitz transform 2 years 10 months ago #964

  • devteam
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Great stuff! Thanks for posting your measurements Peter.. Very useful info!

By the way, you guys are featured in the latest newsletter for your great job at documenting custom filters.
Hoping to see others follow your lead with some similar ideas, and keep up the good work!

DevTeam
MiniDSP, building a DIY DSP community one board at a time.
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Re:Linkwitz transform 2 years 9 months ago #984

  • knuisje
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Yes, another update of the LT spreadsheet. In this version I added a pole-zero plot. For more information see Wikipedia.

Attachment LT_digital_coefs_v1-20100821.zip not found

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Re:Linkwitz transform 2 years 9 months ago #1062

  • KAMIKAZE
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Hello to all, I just purchased minidsp kits and 4-way adv. plugin. Waiting for parcel :)
I already build box for my Peerless XXLS 830846 - 58 liters. Here is measured parameters of it
Fs = 25.43 Hz
Qms = 10.67
Vas = 66.53 liters
Cms = 0.376 mm/N
Mms = 103 g
Rms = 1.56 kg/s
Xmax = 12.5 mm
Xmech = 18.75 mm
P-Dia = 212 mm
Sd = 353 sq.cm
P-Vd = 0.441 liters
Qes = 0.4
Re = 2.6 ohms
Z = 3.12 ohms
BL = 10.23 Tm
Pe = 175 watts
Qts = 0.39
no = 0.257 %
1-W SPL = 86.25 dB
2.83-V SPL = 91.13 dB

Could someone please help me with calculating Linkwitz transform for my box? And give some example. I just not understand all process... :-[
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