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CP-251 Mixing audio

Posted: Mon Jul 22, 2013 3:45 pm
by popmatik
I've just bought a CP-251 for use with my LP and Prodigy. I just want to run something past everyone to see if I'm doing it right :)

I'm currently running the out of the noise on the CP-251 to the four input mixer and then sending the out of that mixer into the audio in on the phatty. This allows me to dial in the level of noise I want. Is that ok to do? I also had the output of my Prodigy going into the mixer to mix that into the Phatty along with the noise. Still ok?

Sorry if that's a total newbie question, I just don't want to be doing something daft with my set up for the rest of my days :D

Cheers

Re: CP-251 Mixing audio

Posted: Mon Jul 22, 2013 6:00 pm
by yesman
That's all fine, have fun!

Re: CP-251 Mixing audio

Posted: Mon Jul 22, 2013 6:03 pm
by popmatik
What an appropriate name you have for that answer Yesman! Thanks for the thumbs up.

Re: CP-251 Mixing audio

Posted: Mon Jul 22, 2013 7:09 pm
by GregAE
Not only that, but if you need LOUDER noise, run two instances of noise through the mixer using the four way multiple at the bottom of the CP-251. It will double the volume.

This little trick works for all signals - not just control voltages. However, when you process audio signals, it's important to make sure that the Offset control is at the zero output position (set dial at 12 o'clock).

- Greg

Re: CP-251 Mixing audio

Posted: Tue Jul 23, 2013 1:10 am
by ColorForm2113
GregAE wrote:Not only that, but if you need LOUDER noise, run two instances of noise through the mixer using the four way multiple at the bottom of the CP-251. It will double the volume.

This little trick works for all signals - not just control voltages. However, when you process audio signals, it's important to make sure that the Offset control is at the zero output position (set dial at 12 o'clock).

- Greg
good tip on the mult! What will happen if you offset the incoming audio?

Re: CP-251 Mixing audio

Posted: Tue Jul 23, 2013 4:36 am
by popmatik
Ah that's great Greg thanks. The Prodigy could do with a little boost so I will try that trick!

The CP has opened up a lot of sonic potential. With the attenuator knobs being a little 'difficult' to set to zero there is always a little LFO modulating things... it really helps bring out the 'analogness' of the synth. Love it!

Now to Kenton socket up my Prodigy and then i'll really be lost in knobbing around! ...and then maybe some Eurorack stuff... :D

Re: CP-251 Mixing audio

Posted: Wed Jul 24, 2013 6:34 pm
by GregAE
ColorForm2113 wrote:
GregAE wrote:when you process audio signals, it's important to make sure that the Offset control is at the zero output position (set dial at 12 o'clock).

- Greg
good tip on the mult! What will happen if you offset the incoming audio?


Hopefully nothing, but keep in mind that you are adding a DC offset voltage to the audio signal if the Offset control isn't zeroed. What can happen?

Depending on the amount, a DC offset will produce an audible 'pop' if you connect the audio output to an amplifier (think of what happens if you were to connect a 9V battery across a speaker - then imagine that effect amplified). Also, some audio processing circuits can become unbalanced with a significant DC signal present.

I'll leave a complete technical explanation to the EE's on the forum, but it's just good practice to observe basic precautions before you start plugging anything into the CV mixer. Although this device CAN mix audio signals, it's important to understand that it wasn't designed to be used this way, and damage (however unlikely) could result if precautions aren't taken.

Better to be safe than sorry...

Re: CP-251 Mixing audio

Posted: Wed Jul 24, 2013 9:14 pm
by ColorForm2113
Ok good to know. Glad it won't burst into flames or anything but I will definitely pay attention to that

Re: CP-251 Mixing audio

Posted: Mon Sep 02, 2013 1:12 pm
by jerryfie
I would like to use an EP-2 to control the volume of the noise on the CP-251, is this feasible?