AdditiveSample playback rate control

Looking for the most simple way to playback the additive samples with a knob that controls rate of playback. I know that the reference manual mentions:
“Pro tip: to scan the sample with a modulation like a graintable synthesizer, set Start its maximum value, and Loop Length to zero. Then Loop Start acts as a “scanner” playing just that slice.”

Had trouble getting that to work, but I’m not sure that’s exactly what I’m after.

I literally mean a slowed down rate, but keeping pitch the same. So, obviously not what a sampler outta the box would do.

Using FL Harmor synth, it’s the “SPEED” parameter – one knob, and I can go super slow or super fast.

Perhaps this is staring me in the face, my apologies if so.

Your synth sounds fantastic. The resolution and structure – ability to freely make blocks, etc, is so great.

Thanks in advance for any suggestions.

I’m just ‘bumping’ my question – does anyone have any ideas – or did I miss it, is there a control like in Harmor, or a simple method staring me in the face?
Thanks.