User Name Stay logged in? Password
 Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read Search

 miniDSP Low cost, modular Digital Signal Processor (DSP) kits for the DIYer from miniDSP.

 12th November 2011, 08:45 PM #1 CharlieLaub   diyAudio Member   Join Date: Mar 2007 Location: California advanced biquad programming: how to set gain for each biquad? I am developing some tools for calculating the IIR transfer function coefficients for the biquads in the MiniDSP. So far I have successfully figured out how to calculate the coefficients for first and second order filter functions and a "gain block" (e.g. b0=gain, all other coefficients=0). I developed my calcs using some of the "cookbook" type of documents that are floating around the web. The one thing I can not seem to figure out, is how to have a filter with a gain of than unity implemented together in the same biquad. I know in analog filter transfer functions I can just multiple the numerator coefficients by the voltage gain that I want to use, and that does the trick. This does not seem to work for an IIR filter. For example, in a single biquad, I want to describe a 2nd order high pass filter with Q=0.7071, corner frequency 500Hz, and voltage gain of 0.707. How to I include the over all biquad gain in my coefficient calculations? I'd like to know a general way to do this for any first or second order filter function. Thanks in advance. -Charlie
 14th November 2011, 06:59 AM #2 minidsp   diyAudio Member     Join Date: Dec 2009 Charlie, If you want to combine Gain (GdB) to one of your biquad filter, there is a simple way. Simply "Multiply" your numerators (all b0, b1, b2) to the linear gain value. (Glin) e.g. H(z) = Glin * (b0 + b1z-1 + b2z-2) / ( 1+a1z-1 + a2z-2) So Glin = 10^(GdB/20) Makes sense? DevTeam __________________ www.minidsp.com - Low cost & modular audio DSP kits for DIYers - Follow our tweets @ minidsp
 18th November 2011, 03:35 PM #3 CharlieLaub   diyAudio Member   Join Date: Mar 2007 Location: California Thanks for your reply. You are correct. I discovered my mistake: in the nomenclature I was following, the numerator coefficients of the transfer function are denoted b0, b1, b2 for IIR filters but are denoted a0, a1, a2 for analog filters. I was just multiplying the wrong set of coefficients! -Charlie

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is Off Forum Rules
 Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home Site     Site Announcements     Forum Problems Amplifiers     Solid State     Pass Labs     Tubes / Valves     Chip Amps     Class D     Power Supplies     Headphone Systems Source & Line     Analogue Source     Analog Line Level     Digital Source     Digital Line Level     PC Based Loudspeakers     Multi-Way     Full Range     Subwoofers     Planars & Exotics Live Sound     PA Systems     Instruments and Amps Design & Build     Parts     Equipment & Tools     Construction Tips     Software Tools General Interest     Car Audio     diyAudio.com Articles     Music     Everything Else Member Areas     Introductions     The Lounge     Clubs & Events     In Memoriam The Moving Image Commercial Sector     Swap Meet     Group Buys     The diyAudio Store     Vendor Forums         Vendor's Bazaar         Sonic Craft         Apex Jr         Audio Sector         Acoustic Fun         Chipamp         DIY HiFi Supply         Elekit         Elektor         Mains Cables R Us         Parts Connexion         Planet 10 hifi         Quanghao Audio Design         Siliconray Online Electronics Store         Tubelab     Manufacturers         AKSA         Audio Poutine         Musicaltech         Aussie Amplifiers         CSS         exaDevices         Feastrex         GedLee         Head 'n' HiFi - Walter         Heatsink USA         miniDSP         SITO Audio         Twin Audio         Twisted Pear         Wild Burro Audio

 Similar Threads Thread Thread Starter Forum Replies Last Post FenderBender11 Chip Amps 37 3rd July 2011 10:23 PM pjpoes Multi-Way 46 22nd January 2011 03:06 AM Flyin11 Car Audio 29 2nd February 2008 09:03 PM yoke Pass Labs 11 26th August 2004 08:12 AM

 New To Site? Need Help?

All times are GMT. The time now is 09:47 PM.