I have been making some quite complex synths which can make amazing sounds but when I try to use them in recordings, they often need a lot of EQ,with strange bumps in the upper mid or lower mid regions compared to my hardware synths.
Do you tend to have any overall EQ or filtering before the output of your PD synths?

Some of it's possibly to do with aliasing.... but not the low mid stuff.

Random thoughts:
Aliasing can theoretically spread all the way to the lower mid range.
In a mix, most instruments / tracks benefit from some EQ
Especially FM synths benefit from low cuts
In practice I equip most synths with a final low cut but I think more specific EQ-ing is better done with a dedicated plugin relative to the mix I am working on.

Thanks for your thoughts. I will work more on anti aliasing.

Adding to it: The benefits of in-synth EQ is that you can make it relative to the midi key pressed. Think of the HPF on a Juno. It's a simple 6db high pass filter with 4 settings: 0,1,2,3 corresponding to octaves relative to the note playing.

Thanks. I was just wondering if it's "standard practise" for people making DSP synths to have an EQ on theoutput that's concealed from the user.
I've been mixing records for 25 years so I'm comfortable with using EQ but surprised by the strange peaks in my Pure Data sounds.

@nuromantix said:

.... but not the low mid stuff.

for any unexpected output of complex synthesis in Pd, very likely this is the cause:

https://forum.pdpatchrepo.info/topic/13709/bug-osc-cos-circle-asymmetry-drifting-out-of-phase

@nuromantix said:

I've been mixing records for 25 years so I'm comfortable with using EQ but surprised by the strange peaks in my Pure Data sounds.

Going back to analog, each internal component of a synth alters the frequency response, the frequency response of the mixer sitting between VCO and VCF has it's input and output frequency response affected by the VCO and VCF it is connected too and in turn it affects the frequency response of the VCOs output circuitry and the frequency response of the VCFs input circuitry. And this frequency response is probably not fixed, as you turn down the mixers volume it may cut some highs and/or even distort the lows which adds frequency content by way of harmonics. Which takes us to the distortion characteristics which are just as complex, dozens of discrete sources adding up and contributing to a complex spectrum. Most digital synths mimic this more complicated frequency response to some degree, either by design or necessity. Pd is ideal and has a dead flat frequency response through the entire chain unless you give it a reason not to have one. If you need to add filtering, than add filtering, not everyone feels the need, it depends on your goals.

Hi. Your filter looks interesting. I have an Xpander here, the filter is probably not as exciting as you would imagine But still a nice synth...... anyway, on topic: I just wondered, I mean I have digital synths that sound good, from the Yamaha DX era up to modern softsynths. I just wonder what is going on under the hood besides the main stuff. I think my problems are mostly caused by aliasing but I can't really oversample much because I'm running out of CPU. Perhaps I'll reduce polyphony to 6 notes and try some different techniques for bandlimited oscillators.

...but something like a Kurzweil K2000 has plenty of aliasing and seems like a pretty naive implementation of oscillators and filters but mostly sounds great, at least in the lower octaves.

@nuromantix Those early digitals are all like 12 or 16bit and 22khz, lower nyquist frequency means aliasing effects are in different frequency band which you may find more agreeable or are so used to working with you don't even really notice. This probably accounts for most of the difference. The output amps and DAC probably play some role as well.

I agree on the xpander's filter, it is generally not very useful to have cascaded filters with the same cutoff and resonance settings, differences between the various modes is small and for the most part the bulk are ignored, but once in awhile they do come in handy. My morphing filter seems more useful but as I said in that post, I do not really do audio in pd and that was just for fun, i have never actually used it. I find the morphing effect more natural than a sweep and combined it can be quite impressive, but it depends on what you want to do. One of these days I will get around to finishing it, only need to figure out the new mix ratios so the resonance never cancels, but it is not a priority and I was sort of hoping someone else would have finished it and uploaded their results. It is kind of laughable that I have not finished it yet, 5 minutes work tops. Perhaps this weekend.