Modfilter still behaving very strange…

[tomylee]

Hey there, now its the time to finally get down on this problem, I have it since every OS the H8000 ever had…

I was hoping maybe with the new beta it gets fixed somehow, but its still the same, everyone please try this patch, im my case I only get a very distorted sound which is there as an attachment and has been created as follows:

Play any sound through the program (in1+2, out 1+2) no signal at the mod input 3+4

1. The distorted sound you hear in the file is my start setting, from there I
2. Raised the q slowly to 5, which cleaned the processing from its distorting effect quite a bit, then I
3. lowered the Q slowly to 0, which completely smashed the signal to silence (would be a nice special fx though 😉 then I
4. lowered the frequency slowly to about 0, and at about 10000hz the sound started to clear up and no distortion was/is audible at lower frequencies then 9000hz regardless of q.

conclusion, the higher the q, the higher I can go with the cutoff frequency for the filter, which is a very strange behaviour, dont you think?

Can someone try this with his unit? It cant be that im the only one with this…or can it…

My setup: H8000 with currently 5.5beta, before 5.2 and all other versions, the behaviour was always the same, so its probably not the version of the OS. I sync the h8k with adat, having no issues there neither, and nor with any other presets that dont use modfilter module.

I have this issue with all modules that use modfilter, so even stock module sound distorted when the cutoff frequency breaches the about 10000hz mark with a q on about 2…

What else can I say, I dont use any sample rate conversion and no other fancy stuff, I really would like to have this exact module checked and replaced if thats somehow possible, I think it has some error in it…

Normally I wouldnt care, but recently I started to program new presets etc and I need this think working like one can expect it to work

So thanks for some advice in advance, I will give you all information you need in order to solve this problem. 

[IDeangelis]

Hi tomylee

I hear it!

I have built a different sigfile. Settings betweem 10100 and 10200, closer to the second value, cause aliasing noise. Adding freq modulation with an lfo makes things even clearer, since a periodic sweep across the above zone triggers the noise. I have kept Q at 1 thru tests. Audio is stereo and analog in, @ 48KHz sampling rate.

Raising the q eliminates alising "almost" completely. I can still hear some "-zzzz" though.

Will pass to DSP dept with accurate description.

Thanks for your report

Italo

[tomylee]

hi Italo,

any news from the dsp department?

greets
tomylee 

[IDeangelis]

Hi tomylee

The problem you are experiencing is inherent with the state

variable filter which is the topology on which the modfilter is

based.  The problem is that when the cutoff frequency gets to about

2/5ths of the sample rate, you will get that noise and distortion.

There is no solution at the moment. Avoiding that 10KHz threshold is the only possible way to use it right now.

Hopefully a new module or a newer version of the current one will be released.

The bug is in the database.

all the best

I

[tomylee]

well lets hope its not just hopefully, dont you think too? I guess solving this problem is rather easy

when can I (we) calculate with the solution of this bug?

greets
thomas 

[IDeangelis]

Thomas

there is no time frame I can provide you. Let's hope, as you say, it won't take too long.

all the best

Italo

[ThreeFingersOfLove]

How about in the public 5.5. OS version? 😀

[IDeangelis]

For the time being the solutions are:

a) avoid the critical threshold

or

b) work at 96KHz

best

I

[tomylee]

Hello,

Ive seen 5.5 is out!

Has the issue been sorted out? One cant even make a decent modfilter with that issue, completely useless module, wonder why not more ppl are complaining..

cheers
tomylee

[Author]

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