Best EQ for save CPU load
To PD Gurus:
In my PD project I need to insert a simple 3 bands eq over 120 audio channels.
Big trouble is I'm using an old AMD Athlon processor computer and I need the best EQ for saving CPU load. I don't need extremely "quality" EQ. Simple 3 bands EQ and low CPU load.
What do you think is the best option?
Some patch or example?
Thanks a lot in advance.
I can't understand how can I do it.
You could use a loadbang and messages to set the faders to a default value. The EQ abstraction that Hardoff provided already has a switch. If you compare the value of the faders with their default using [==] then the EQ can be activated as soon as someone moves a fader. You may need to wrap this so that the faders are outside the DSP. An EQ-OFF function that sets the faders back to their defaults will switch off the EQ abstraction.
In practice only a few of the channels will have active EQs, so you save a lot of CPU by only switching them on as needed.
In hardware digital mixing desks (like the Yamaha, HHB, Roland etc) you will see they have a limited number of EQ blocks divided amonst all the channels. Once you've used them all up, no more. 120 channles is quite a lot and it's unlikely more than 1/4 of all the channels would need an EQ. An audio routing system that inserts EQs as needed from a limited pool might be best.
See if you can work out how to do the automatic switching first.
a,
Use the Source.
ok, here's how i was suggesting to do it. see attached 8 channel version.
a little off topic to hardoff
how did you make the [pd eq]s have the attached slider gui like that?
right click on an empty part of the canvas and select 'graph on parent', and then adjust the dimensions to fit the sliders.
and then for each slider, click 'init' so that the value is initialized when the patch is loaded.
I needed an eq that could modify 4 channels with the same group of faders for a four channel work, so I modded hardoff's. Thought I'd repost out of respect/ in the hope it could be useful to others.
Put it in a folder with your patch and make a new object called "eqsection".
I am looking for a CPU-cheap EQ. I tried someones (included the ones from this thread), but they all use biquad~... or fft~ (Katja). Thanks everyone for sharing.
If bp~ and vcf~ are cheap for CPU... Why I found just one person who did it? (http://puredata.hurleur.com/sujet-4281-patch-return-keyboard-controllable-equalizer) Would it be low-quality?
I know that an EQ is not so easy for processing... but I tried putting a mono EQ7 for my microphone and a stereo one for the output... but my CPU got on fire (because my patch is consuming 26% doing nothing and 30% at full working... but this is another issue in another thread).
The one for my microphone is because, maybe, I will use different ones (SHURE SM-58 and SHURE Headset), they sound different. I would like them to sound similar. And, the output is for general EQ and to avoid possible acoustic feedbacks (because of some FXs with feedback, as delays).
Suggestions?
Maybe a bp~ EQ5-7 for the mic, a EQ3 for general-out and a band-stop for the feedback?
[biquad~] really isn't that inefficient at all. It's just calculating the coefficients that takes some processing. You might want to look at my [filtercoeff.mmb] abstraction. It generates coefficients for EQ-style filters.
I wouldn't use [bp~] because the phase response is weird and it can be noticeable. It also has a frequency response that looks more like a resonant low-pass than a band-pass. [vcf~] isn't so bad when it comes to phase response, but the attenuation of the stop-band is frequency dependent IIRC, which can make it a bit tricky to get expected levels when summing it with other bands. And, obviously, neither of those will let you come up with some shelving or hp/lp filters.
Ideally, if you're using an EQ with several filters, you would be able to bypass and [switch~] off the ones you're not using. That should save you some processing. Unless your using a graphic EQ (e.g. a bank of parallel band-pass filters), but those aren't really that great, anyway.
It's a bit difficult to understand for me... but thank you very much for the explanation.
Maelstorm, I won't use EQ for FXs... just one EQ for the input (microphone) and one for the output (speakers).
I like your gui.eq7.mmb~ (and eq7.mmb~)... I like it because it has switch~ (I love switch~). So, if I don't need to equalize, it doesn't spend process. I think I will use it for the output.
But I don't know which I should use for the input to make one mic sounds like the other (hand mic and headset mic). I had been using the one with lop~s and hip~s and it worked well (for my ear)... What about this technique? (I attached the file... but remember that it is old, it was a subpatch and even it did't use "$0-" variables).
Maelstorm! I don't find eq7.mmb~-help.pd file! It is not in GitHub...
Also, a lot of "expr divide by zero detected" messages appear when I open gui.eq7.mmb~-help.pd.
@MarioMey said:
Maelstorm! I don't find eq7.mmb~-help.pd file! It is not in GitHub...
Also, a lot of "expr divide by zero detected" messages appear when I open gui.eq7.mmb~-help.pd.
I haven't made a helpfile for it. But, really, just look at the messages that come out of the middle outlet. Those are all the messages that work with [eq7.mmb~]. And don't sweat those "divide by zero" errors. Those just pop up when the [filtercoeff.mmb] astractions are initializing, but by the time it's done initializing they are taken care of.
As far as getting the mics to sound similar, that's mostly something you'll just have to do by ear, and you're not likely going to nail it. You could use the analyzer on [gui.eq7.mmb~] to help you. Try and run white noise through both mics, and adjust the EQ of one so the analysis looks as similar as you can get it. That might at least get you on the right track.
I told you about its help file, because, in gui.eq7 help file, it says "All other messages are the same as [eq7.mmb~]. See it's helpfile." But I had used the out messages to learn how to change its parameters.
To get one mic sounds similar to another... is "more or less". Last year, I did it with a by-me-made eq5, using lop~ and hip~. I wanted to know if that technique was "aberrating".
Another eq.mmb would eat my CPU. I'm already using two, for stereo-out.
EDIT: finally, I put EQ3 from Hardoff modified to have a band bypass (switch~) and general bypass. For the output, gui.eq7.mmb~ and eq7.mmb~ (both channels).
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