# Preferred filters in CSound?

**URL:** <https://forum.cabbageaudio.com/t/preferred-filters-in-csound/4399>\
**Category:** Csound Noobs\
**Created:** [1 July 2024 05:04 UTC](https://forum.cabbageaudio.com/t/preferred-filters-in-csound/4399 "2024-07-01T05:04:36Z")\
**Posts on this page:** 9\
**Page:** 1

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**Author:** ![Bryan\_T](https://forum.cabbageaudio.com/user_avatar/forum.cabbageaudio.com/bryan_t/32/5680_2.png) [@Bryan\_T](https://forum.cabbageaudio.com/u/Bryan_T)\
**Post date:** [1 July 2024 05:04 UTC](https://forum.cabbageaudio.com/t/preferred-filters-in-csound/4399/1 "2024-07-01T05:04:36Z")

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I’m adding a few filters to my project. I wanted a low pass filter and a high pass filter. I think I opted for lowpass2 and bqrez. But it made me wonder if there are preferred implementations. Thoughts?

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**Author:** ![nymano](https://forum.cabbageaudio.com/user_avatar/forum.cabbageaudio.com/nymano/32/4711_2.png) [@nymano](https://forum.cabbageaudio.com/u/nymano)\
**Post date:** [1 July 2024 07:40 UTC](https://forum.cabbageaudio.com/t/preferred-filters-in-csound/4399/2 "2024-07-01T07:40:05Z")

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In the manual there is a dedicated Filter section, I think it can help you decide which filter would suit your needs: [The Csound FLOSS Manual](https://flossmanual.csound.com/sound-modification/filters)

I suggest trying the examples to see which one sounds good for your project 🙂

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**Author:** ![rorywalsh](https://forum.cabbageaudio.com/user_avatar/forum.cabbageaudio.com/rorywalsh/32/165_2.png) [@rorywalsh](https://forum.cabbageaudio.com/u/rorywalsh)\
**Post date:** [1 July 2024 10:13 UTC](https://forum.cabbageaudio.com/t/preferred-filters-in-csound/4399/3 "2024-07-01T10:13:19Z")

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Check this out too:

[https://forum-next.cabbageaudio.com/t/csound-filters-demonstration/192](https://forum-next.cabbageaudio.com/t/csound-filters-demonstration/192)

Might need some updating, but a great demo instrument.

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**Author:** ![Bryan\_T](https://forum.cabbageaudio.com/user_avatar/forum.cabbageaudio.com/bryan_t/32/5680_2.png) [@Bryan\_T](https://forum.cabbageaudio.com/u/Bryan_T)\
**Post date:** [1 July 2024 11:02 UTC](https://forum.cabbageaudio.com/t/preferred-filters-in-csound/4399/4 "2024-07-01T11:02:03Z")

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I tried several last night, basically running a sawtooth wave through them and listening. Obviously, there were differences in sound. And some of them respond quite differently to resonance changes, which scared the heck out of me when they blew up!

But I’m also curious about their computational demands. I’m not sure how to assess that.

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**Author:** ![rorywalsh](https://forum.cabbageaudio.com/user_avatar/forum.cabbageaudio.com/rorywalsh/32/165_2.png) [@rorywalsh](https://forum.cabbageaudio.com/u/rorywalsh)\
**Post date:** [1 July 2024 11:04 UTC](https://forum.cabbageaudio.com/t/preferred-filters-in-csound/4399/5 "2024-07-01T11:04:33Z")

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I don’t think any of them will demand too much CPU to be honest. You can use the [cabbageProfiler](https://forum-next.cabbageaudio.com/t/new-profiler-opcodes/4278) opcodes to test them.

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**Author:** ![Bryan\_T](https://forum.cabbageaudio.com/user_avatar/forum.cabbageaudio.com/bryan_t/32/5680_2.png) [@Bryan\_T](https://forum.cabbageaudio.com/u/Bryan_T)\
**Post date:** [1 July 2024 11:48 UTC](https://forum.cabbageaudio.com/t/preferred-filters-in-csound/4399/6 "2024-07-01T11:48:47Z")

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That’ll be a useful tool!

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**Author:** ![Oeyvind](https://forum.cabbageaudio.com/user_avatar/forum.cabbageaudio.com/oeyvind/32/4681_2.png) [@Oeyvind](https://forum.cabbageaudio.com/u/Oeyvind)\
**Post date:** [2 July 2024 16:37 UTC](https://forum.cabbageaudio.com/t/preferred-filters-in-csound/4399/7 "2024-07-02T16:37:41Z")

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Among all nice options, I find the butterworth (butterlp, butterhp, …) to be a good bread and butter filter for general use.

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**Author:** ![Bryan\_T](https://forum.cabbageaudio.com/user_avatar/forum.cabbageaudio.com/bryan_t/32/5680_2.png) [@Bryan\_T](https://forum.cabbageaudio.com/u/Bryan_T)\
**Post date:** [3 July 2024 04:39 UTC](https://forum.cabbageaudio.com/t/preferred-filters-in-csound/4399/8 "2024-07-03T04:39:28Z")

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I’m doing some stuff where I’m putting a filter in the feedback path of a delay line. Those buttereorth filters are really great for that since they are so well behaved. Filters with resonance can cause the feedback loop to blow up.

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**Author:** ![zephyrbrooks](https://forum.cabbageaudio.com/user_avatar/forum.cabbageaudio.com/zephyrbrooks/32/5627_2.png) [@zephyrbrooks](https://forum.cabbageaudio.com/u/zephyrbrooks)\
**Post date:** [9 July 2024 21:39 UTC](https://forum.cabbageaudio.com/t/preferred-filters-in-csound/4399/9 "2024-07-09T21:39:29Z")

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Hello,  
According to me using lowpass2 and bqrez are good choices for implementing low pass and high pass filters. The preferred implementation can depend on the specific requirements of your project, such as the desired frequency response, computational efficiency, and ease of tuning.
