I'm trying to go from digital filters to analog since I havent found a good solutions with good enough converters for the digital part!
I'm building a three way system and so far my plan was to use MiniDSP for the bass because it's gonna be extremely expensive with a good passive filter- but then I thought that maybe I could make a active filter for the bass, just like on my old sub amps.
My question:
How can I make a 24db LR filter for the bass at 300hz, or even better with a trimable frequence?
The amps are TPA3255 1x480W 1Ch Class D Audio Amplifier | eBay
I'm building a three way system and so far my plan was to use MiniDSP for the bass because it's gonna be extremely expensive with a good passive filter- but then I thought that maybe I could make a active filter for the bass, just like on my old sub amps.
My question:
How can I make a 24db LR filter for the bass at 300hz, or even better with a trimable frequence?
The amps are TPA3255 1x480W 1Ch Class D Audio Amplifier | eBay
IMHO, if you are using chip amps it is better to separate low and high frequencies at low level, and amplify them separately. I did it using an 800Hz Butterworth filter, and a TDA2030 for bass and a TDA2003 for highs, from a SPMS giving ±14V for the former and 12 for the latter.
What I want to do is to use two amp's per speaker, so one amp for the bass and one amp powering the mid and the tweeter, and my big question is, how do I make the crossoverfilter, pre amp for the bass - Does it make sense or have I misunderstood what you wrote? 🙂
This is for a line level filter (before the amplifier), with a sample calculation.
Online Calculator .:. Active Butterworth Lowpass Filter Calculator
Given: Maximum Freq. [kHz] 0.300
Given: R [kΩ] 20
C1 [nF] 28.712
C2 [nF] 24.507
C3 [nF] 69.312
C4 [nF] 10.151
Online Calculator .:. Active Butterworth Lowpass Filter Calculator
Given: Maximum Freq. [kHz] 0.300
Given: R [kΩ] 20
C1 [nF] 28.712
C2 [nF] 24.507
C3 [nF] 69.312
C4 [nF] 10.151
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I hope it's okay with my noob questions! I did some digging and found Filter Design Tool
And I came up with the following design 4th order bessel with 15+- voltage supply
filter-design-report-2.pdf - Google Drive
Is it as simple as building this circut and adding it in front of my TPA3255 amplifier?
And I came up with the following design 4th order bessel with 15+- voltage supply
filter-design-report-2.pdf - Google Drive
Is it as simple as building this circut and adding it in front of my TPA3255 amplifier?
Bessel? Not sure that's a good idea for a cross-over - the point is to cross-over to the next driver smoothly, and Linkwitz Riley is probably the first port-of-call for designs.
I am intrigued why you have been unable to find a solution with good enough converters. What has been the problem?
That the conversion of what I have tried so far, litterally has killed the music compared with my Lynx Aurora converter - And that I havent found a system with usable digital outputs, ADAT, Dante or AES, that I can afford- Besides the Aurora DSP system, which i'm hoping for will be ready with ADAT out soon! 🙂
minidsp nano digi is spdif in and out. SPDIF to AES converters are easy to buy/make then add converters of your choice (or use your lynx).
In the opening post you asked about a Linkwitz-Riley filter. A Linkwitz-Riley filter is equivalent to a cascade of two Butterworth filters of half the order, so when you use the calculator rayma referred to, use it to design a second-order Butterworth filter and put two of those in a row, you have your fourth-order Linkwitz-Riley.
I've build a 3-way active state-variable filter.
That you can rather easy trim by using (electronic)variabel resistors.
Active audio crossover filter - Elektor LABS | Elektor Magazine
That you can rather easy trim by using (electronic)variabel resistors.
Active audio crossover filter - Elektor LABS | Elektor Magazine