Info on Volta's ramp automation

Discussion and support for MOTU's Volta software.

Moderators: Kent, stretta

Post Reply
User avatar
doctorvague
ole fuckity fuck
Posts: 3096
Joined: Fri Nov 14, 2008 5:40 pm
Location: New Mexico, USA

Info on Volta's ramp automation

Post by doctorvague » Tue Oct 20, 2009 3:32 pm

I hadn't had a chance to try Volta's ramp automation but did today. At first I thought the ramps would be in a MIDI track aimed at Volta but you actually do it in the Volta track itself which makes sense. For some reason I had a notion to hook my oscilloscope up to the 24i/o to see what was happening (and I figured it would look cool to see the same ramps on the scope as the screen - it does). What the manual doesn't tell you and the ramp automation doesn't indicate is that the ramp output is bipolar. When I pulled up the ramp and plugged in the scope it jumped to -5V. I was confused at first and then entered in a ramp and realized that Zero ramp =-5V, .5 ramp (halfway up) = 0V and 1 ramp (full up) = +5V. Keep in mind with the ramp inserted, until you've entered in non-zero ramps in the track, it will be outputting -5V by default.

Without a scope or voltmeter this might create some confusion and should have been documented IMO, so I thought I'd post it here for you Voltars.

Cheers
Phil

User avatar
stretta
Veteran Wiggler
Posts: 698
Joined: Sat Jan 17, 2009 3:43 pm

Post by stretta » Wed Oct 21, 2009 2:41 pm

Ideally, voltage sources like ramps (and others) would have a unipolar/bi-polar user-selectable option.

Anyway, sorry about the confusion. Good thing to point out.

User avatar
1nput0utput
Common Wiggler
Posts: 212
Joined: Tue Apr 14, 2009 10:00 pm
Location: USA

Post by 1nput0utput » Wed Oct 21, 2009 4:46 pm

If I'm not mistaken, it won't be -5V for all interfaces. It'll be the lowest possible negative DC voltage that the D/A output is capable of producing. For some audio interfaces that might be -5V, but it could be less (like -2V) for D/A outputs that have a narrower total output voltage range.

User avatar
doctorvague
ole fuckity fuck
Posts: 3096
Joined: Fri Nov 14, 2008 5:40 pm
Location: New Mexico, USA

Post by doctorvague » Thu Oct 22, 2009 2:55 pm

1nput0utput wrote:If I'm not mistaken, it won't be -5V for all interfaces. It'll be the lowest possible negative DC voltage that the D/A output is capable of producing. For some audio interfaces that might be -5V, but it could be less (like -2V) for D/A outputs that have a narrower total output voltage range.
Indeed and good point to clarify.

Another thing to keep in mind with these kinds of voltages that are not 1V/Oct is that with an insert cable (in my case anyway with TRS) you have the inverse of the ramp available as well without using another audio output.

I had a friend over later and we had some amusement as I drew ramps in real time as DP was running and then we could see the ramps go by on the scope at the modular. But then we're easily amused. :mrgreen:

Post Reply

Return to “Volta”