configuring slave board input
Thread Summary
The user asked about configuring a slave board for subwoofers and whether to send only low-frequency signals through a low-pass filter. The engineer confirmed the need for a DC block filter and provided several project examples for different crossover configurations, including time alignment and potentiometer control for frequency and volume. The projects cover basic crossovers, 2.1 speaker setups, and multi-way speaker systems using the ADAU1701, KABD-4100, and parametric EQs.AI Generated Content
Hello. I'm not sure if configuring is the correct term but it was the best I could come up with. My question is when setting up a slave board to run subwoofers. Do you or should you only send low frequency signals to it? Meaning running the signa through a low pass filter on the master board before sending it to the slave. One more while I'm at it, when configuring a POT to control frequency, would i link the POT to a parametric eq? If not, how would I go about doing this? Do I need to use a DC filter/ Sorry if these seem like silly questions. I've learned just enough about DSP to be very dangerous but trying to get better. Thank you for your time
Thread Notes
diyhfi - Moved from SigmaDSP Processors & SigmaStudio Dev. Tool to Processors & DSP. Post date updated from Sunday, January 25, 2026 3:23 AM UTC to Friday, March 27, 2026 3:03 PM UTC to reflect the move.
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Hello diyhfi,
Your first basic question is basically very simple, do what you want to do or need to do! I cannot say there is a right or wrong way.
Yes, you do need to use the DC block filter because the DC offset of the ADC converters are always there.
Some of your questions are answered on the forum over the years.
You also made no mention of time aligning the woofer and subwoofer.
I will attach several project to show several things. These projects are all most likely already up here in other posts.
This first project is a basic crossover with a sub output. This is only for one channel. So one DSP for each channel.
There is no time alignment in this project but you will see the DC block filters. No remote or external control in this project.
0636.ADAU1701 Crossover with Sub Output.dspproj
This next one below, It for the Dayton Audio KABD-4100 board. This one shows the time alignment delays.
This one uses an external pot for volume control.
7356.Stereo 3-Way Speaker via cascaded KABD-4100 (MASTER LEFT CHANNEL).dspproj
This one below is a 2-way with time alignment. So just a woofer and tweeter. But, it shows how to use a MUX to switch between two different filters with an external switch.
1070.Stereo 2-Way Speaker project with preset switching via GPIO switch.dspproj
This one below is a 2.1 crossover so this is close to what you want from what you mentioned. There is some time alignment. But, it also uses a pot to control the bass shelf filter. An index selectable filter with 19 different curves.
3872.1 Speaker Project with Potentiometer Tone Controls.dspproj
Enjoy!!
Dave T
Hey, thank you so much. I look forward to trying these out.
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