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Generating audio tones low very low frequency with VVVVAudio

vvvv beta question
#1

Hi !
i m quite strugling to understand what i m doing with the VVVVaudio nodes.

I m trying to generate unaudible frequency sending it to a subwoofer, to move air.

with tonfilm’s help (1000X thxs), i can generate audio tones, and unfortunately crashing VVVV a lot with it (just moving values in 0 or minus values is noyt at all well supported by vvvvaudio).

as i m actually inside my research, there is 2-3 points i m not understanding:

  • can I generate unaudible frequencies in very low bass with a basic soundcard ?

  • where can i find a tutorial for VVVVaudio for non audio people ? where can i get help patches or video to understand the concepts ?

  • all the vst (seraching for a plugin) i have donwloaded are crashing inside the vst host (vvvv x64 version). any idea of what is missing (i m running asio4all)

voilà !

Oscillator Test MODIFIE.v4p (27.5 kB)

#2

  1. it depends on your sound card. most sound cards are not what is called DC coupled, which mean that they have a high pass filter in place that will cut off frequencies that it cannot handle well. MOTU are know for making audio interfaces that are DC coupled.

  2. look at the girlpower patches in the VAudio pack folder and here: https://vvvv.org/contribution/vvvv.audio-node15-workshop-patches

  3. you are probably using 32bit vsts, you should use 64bit vsts or use 32bit vvvv

#3

thanks a lot sunep ! :)
good thing to know about this DC coupled topic…

just trying to figure out what is the best approach for my project…

i would like to generate a pulse of specific frequency and time that i will remote in artnet.

#4

Hum, are you talking about this kind of problematic sunep ?

http://www.whence.com/soundcard-dc-dac/

#5

not sure, I never hacked an audio interface like this. but getting a cheap USB interface would make the test easy.

I changed your patch a bit to how I would have done it

Oscillator Test MODIFIE-2.v4p (27.7 kB)

#6

I mean yes, that is how you could do it if you don’t want to splash out on a more expensive audio interface.

#7

you could also check if that works, a bit different use case but same problem i guess:

http://www.expert-sleepers.co.uk/siwaacencoder.html

#8

Cheap soundcards (I don’t know if expensive ones do different, but building a homebrewn laser controller too, I encountered this on cheap cards:) usually use a ‘virtual 0’ potential. They create the audio wave around a potential of say 1,45V.

In order to create a balanced signal again they pull the signal towards the virtual 0 with a capacitor. This acts like a highpass filter, and doesn’t allow you to hold a signal level for a suspended time. The slower your waves go, the more energy you have to use to keep the level.

If you remove the capacitor from the soundcard output and add a voltage divider against your power source, you can create a symmetrical signal around a proper 0V.

not sure if that helps …

#9

hum hum… thanks a lot for all those informations ! really i appreciate ! thxs !

i will see in a couple of days with two cheap cards i have if there any improvement possible… with resistance trick. I have a friend who is good in electronics, we will see from eno sugestion !!!

sunep… what is puzzling me, 2 things:

  • what is the idea of multiplying by a trigger ? can you just give me a basic understanding of te concept of vvvvaudio tools ? i have run the samples, but well, V2A doesnt have any sense for me ! (one exemple)

  • and… how to send on bang just ONE impulse… is it thruth the audio engine PLAY that i need to pass ?

Other thing i let this patch run a moment, after a 15/25 minutes, rythm is changing… a question to see with trigger sequence parameters ?

#10

  1. that is because in VAudio all signals are audio, meaning that by multiplying the tone by 0 mutes it and by multiplying by 1 you turn it on, I think this is very MAX/MSP like.
    V2A just converts a normal value in vvvv into an audio signal so it is possible.

  2. generating an impulse is not built into VAudio, but you can fake it by playing back a wave of an impulse in FileStream (VAudio): https://www.freesound.org/people/unfa/sounds/205620/ (you should edit it so it starts with the impulse)

#11

an impulse can also be done with the TriggerSequence… set it to length 1 and calculate the duration to be one sample: (60/BPM)/SampleRate
if you want to have length 4 you have to divide by 4 again ((60/BPM)/SampleRate)/4

with ADSR it might also be possible to generate one…

ADSR can also be used to avoid clicks, if it has 0.01 as attack/decay and 1 as sustain it acts as a filter and is cheaper for the CPU than the Filter node.

Oscillator Test MODIFIE-3.v4p (32.3 kB)

#12

There is also the rarely used SourceBuffer (DShow9), which accepts a spread of values to fill a buffer that is then played back as audio. Not v-audio compatible though.

#13

Ah, there we go in a kind of nice solution if i have already my samples. thanks a lot for patches and solutions. VAudio seems for me not enough stable / understandable. needs to be a soundman somehow. i will try the suggestion of pre recorded samples !!!

thanks a lot evvverybody !

#14

if you want a steady stream of pulses, I think VAudio is the only solution that will deliver that atm. I have tried with other ways og making sequences in vvvv and if it is running in mainloop it is not tight and it is drifting because of the for audio and rhythm low framerate.

#15

for my project i m trying to perturbate sand jet, and this will be done with pulses… i make tests today with sample and see. merci sunep ! :)

#16

ok, samples are less, very less effectiv than VVVVAUDIO
to move sand, i m obliged to saturate the gain, to obtain a good air movement

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