BlahBlahCafe - Jean-Michel Jarre forum

I'm the twinbrother of Harry Potter, so that doesn't have to be a problem

The Laserharp is polyphonic? If not, what can do to turn to polyphonic? What happens when put the hand on laser (eletronically)?

I doubt the laserharp is polyphonic. So when you put two hands on two different beams, it depends on the settings which one is triggered. Monosynths can be set to play the highest or lowest played note (highest note priority / lowest note priority).

In Merzouga it was, I thought he hit 2 beams, which resulted in 2 notes...

Explain to me how he can trigger two notes from one (splitted) beam. You alwaysaseverwiseass

Eer... Lemmetry: That beam is changing from note every 1/25 th second, so in fact it's monophonic, but it changes that fast, that you don't hear the changes?

Then it should be set up to trigger one note after the other and repeat that... still you will hear it even if it changes that fast. Such a setting wouldn't make much sense anyway, cause the thing is not designed to play pads or sth.....

Jarp2600 wrote:Eer... Lemmetry: That beam is changing from note every 1/25 th second, so in fact it's monophonic, but it changes that fast, that you don't hear the changes?

Changes like that in electronics are barely noticable, but engineers still use small circuits to over come this tiny problem. I expect a Schmitt Trigger (great little thing that converts a fluctuating signal into digital (on/off)) would be used to stabilise this so that the gate signal is constant, not dipping every 1/25 of a second. (I doubt that on every 1/25 the signal goes completely off, it'll just dip. Otherwise, schmitt triggers wouldn't work in this case, but a monostable would (this converts a short trigger into a longer pulse, usually using a 555 chip).

Sorry if everyone's now baffled.

I don't see why you'd make it polyphonic, but it could be done fairly easily... I think.... If JMJ himself triggered off 2 notes "live" with the laser harp and they both played, then yes it is polyphonic. However, (long time since I've seen one in action) doesn't the laser harp have a couple of lasers to control things (octave up/down) or are these pedals? There's definitely a way of changing octave with the harp on its own, I've seen it in concerts.

jarrekid wrote:There's definitely a way of changing octave with the harp on its own, I've seen it in concerts.

That's done remotely.

Hmm I thought I had already posted an answer in here, but it has disappeared

The laserharpe could well be controlled backstage from that piece of software I remember I saw on a picture from a JMJ concert. On the screen there was a single octave keyboard (if not two). I don't remember the other functions but I suppose they did all that octaveshift etc with that.

I bet the laser harp is the principle of a function in the Casio VL-Tone; you can program a melody in its memory, and then you can play it back by hitting one single key as many times, as the number of notes the melody consist of.

Not really...
How could JMJ make mistakes then? (Lille '97 e.g.)

GeeJee wrote:Not really...
How could JMJ make mistakes then? (Lille '97 e.g.)

I don't recall that. I only remember him hitting different beams for the same notes.

AnDrOiD wrote:

GeeJee wrote:Not really...
How could JMJ make mistakes then? (Lille '97 e.g.)

I don't recall that. I only remember him hitting different beams for the same notes.

I put that down to the remote control and re scaling of the harp.

AnDrOiD wrote:I bet the laser harp is the principle of a function in the Casio VL-Tone; you can program a melody in its memory, and then you can play it back by hitting one single key as many times, as the number of notes the melody consist of.

But then again he changed the melody sometimes doing the tour. From the Katowice video you can see that he hits other beams and get another tone. As Gee mentioned there were some mistakes also, he was also wearing a coat which have also hit a laserbeam when he turns around for the mellotron part.