Question regarding use of sweep delay

[lauke-lux]

After having discovered there is a sweep delay in the unit (thank you Simeon, BTW for me: please RTFM !!), I started to experiment a bit with it.

I found this in the manual :

5.6.5 Sweep Delay
The Sweep Delay uses the same algorithm as the Stereo Delay (above, p. 67), but adds an LFO-driven stereo
bandpass filter after the outputs of the delay.
START FREQ, STOP FREQ – These controls set the range of the filter sweeps.
RESONANCE – Sets the resonance of the filter. Some might describe this as an “intensity” control.
SWEEP TYPE – Sets the waveform of the LFO that controls the sweeps. See section 16.8 on p. 161 for more
information on LFO waveform shapes and phase.
SWEEP RATE – Sets the speed of the sweeps.
SWEEP TEMPO – Locks the SWEEP RATE parameter in rhythmic relation to the global tempo.
SWEEP PHASE – Adjusts the phase differential between left and right sweep LFO waveforms.

I wonder how the LFO control does affect the sweep. Should I understand that a sawtooth (steep part in beginning) will make the sweep trajectory going from High to Low frequency of the sweep bandwidth. Supposing that was right, hence how does LFO frequency affect the sweep as there is already SWEEP RATE ? Or does the sweep rate affect the LFO frequency ?
Is Resonance a bit like influencing the Q + the bandwidth of the frame (or can I say : comb filter ?) that will be driven by the LFO through the sweep bandwidth (ie Start and Stop frequency) ?

 

[simeon]

Should I understand that a sawtooth (steep part in beginning) will make the sweep trajectory going from High to Low frequency of the sweep bandwidth.

> yes. and then jump straight back up to high again

Supposing that was right, hence how does LFO frequency affect the sweep as there is already SWEEP RATE ? Or does the sweep rate affect the LFO frequency ?

> sweep rate is the speed of the sweep. there is no parameter called lfo frequency

Is Resonance a bit like influencing the Q + the bandwidth of the frame (or can I say : comb filter ?) that will be driven by the LFO through the sweep bandwidth (ie Start and Stop frequency) ?

> resonance is similar to Q



if you want to visualise what these look like, then attach an internal lfo controller to the frequency in a filter block set to bandpass and watch the image of the curve move around as you change the various parameters of the lfo

 

[lauke-lux]

Thanks Simeon, started to dig this tonight & will have to work this out a bit. Am quite interested in recreating the effects that an english band Addict used on their album "Stones". Thought for a long time they did this with a Murf until I heard a demo of the Line6 DL4 lately. Definitely comes quite close to that sound, and I worked just about half an hour on it. Just will need to work on the waveforms/start stop band frequencies, feedback and mix parameters to get it "subtle" enough.

Also I messed around a bit with the tape config of the sweep delay and was surprised how a powerful fool this feature is. RHCP used this kind of technique for the pitched chordal sounds close to the end of Dany California. Does anybody here have any info available relating pitch to band speed (what speed delta to use for obtaining octave and/or half note steps)? Using this with a step/envelope controlled sequencer and some feedback should be quite funny and give this typical tapestreamed pitch sound I guess...Actually I do this song using two pitch blocks and two user harmony scales for the first & second part of the last part of the song, but it would be way more powerful with the sweep delay in tape delay configuration.
Looking forward to work this out next weekend, holy shit and this all was in the box since I bought it in 2012 !

 

[simeon]

You may find it easier to use the mono tape delay with a bandpass filter block after it. Both in a side chain. Then you could modulate the motor speed parameter, which would make the maths much easier.