Eventide Rose delay numérique et analogique à la fois

One consequence of the bit bucket, non-DSP, approach is that any processing desired has to happen in the analog world.

tu veux dire que c'est "analog dry through" ? Les pédales TC Electronic le font déjà depuis plusieurs années

Non, la tr est un delay analo bbd piloté numériquement. Ici la ligne de retard est numérique si j'ai bien compris, mais tous les filtres sont analogiques. Mais ce n'est pas nouveau : le Pigtronix Echolution 2 est construit autour d'une architecture similaire.

It's not like that. The H9 creates its effects using Digital Signal Processing, a DSP chip to execute our DSP algorithms. In theory DSP can do everything and Eventide has gotten rather good at creating DSP-based effects. With DSP, the analog signal is sampled at fixed sample rate and then the ones and zeros that represent the audio are added, multiplied, delayed, re-sampled, FFT'd, LPC'd, etc.

A few years ago we asked the question - Is there something that DSPs can't do well? and that had us thinking about some of our first products. Years before DSP was practical. In fact, back in the day, analog electronics could do everything except delay audio. Folks used tape machines back then for delay. The first digital box, our 1745, was simply a delay line because, when it was first practical to digitize audio, there were no DSP chips or any processors that could do anything useful with the digitized audio.

Of course this was a time before there were any standards for digital audio. The first standards came ten years later with the introduction of the CD (44.1kHz, 16 bit). So, back in the day one simple 'trick' was to sweep the sample rate, the clock. Then ~1974 bucket brigades became available. These devices were (and are) capable of short delays. They are not digital in that they don't convert the analog signal to ones and zeros but rather pass analog samples along a series of capacitors and switches. The typical BBD had ~1000 stages. Analog goes in one end and 1000 clock ticks later it's spit out the back end. So, if you clock the BBD at 50 kHz, you get a 20 msec delay. Want a longer or shorter delay? Clock slower or faster. IOW, vary the clock speed.

BBD's have an inherent limitation. As the sampled analog signal is passed along, not unlike trying to pass along buckets of water really really quickly, you get some spillage. That means, for audio, you get noise, distortion, etc. For short delays, BBDs work well enough when the delay is longer than a couple of hundred msec it's, well, a mess.

Eventide's Instant Flanger used BBDs and we always liked something about the sound of sweeping the sample rate. In fact, the H910, which also was 100% DSP-free, used a swept sample rate even though it was true digital. Again this was before there were standards or any other digital thingies to connect to.

So, Rose. We had the thought that it might be fun to create products with wildily sweeping sample rates. We remember that there was something different about the sounds that those old non-standard pieces of gear created. We came up with the idea of creating a digital bucket brigade, marketing is calling it a 'bit bucket'. A bit bucket doesn't do any 'processing', no DSP. But the bit bucket overcomes two major limitations of analog BBDs.

1) They can be many seconds long.

2) They can go backwards.

We've spent quite a bit of time on creating this platform and have other products in mind but let's see how Rose is recieved. It's weird and kind'a hard to wrap your head around (well, my head anyway). The folks who have tried it all say that it sounds different than anything else that they've used. That was the goal and the hope. It's a sound that would be difficult to achieve using standard DSP techniques. That's why it won't be an H9 alg.

One consequence of the bit bucket, non-DSP, approach is that any processing desired has to happen in the analog world. Mixing, filtering, feedback, soft sat are a snap if you have a DSP chip and write some code. Rose doesn't. So, it's a bit pricey to build with lots of analog components but it sure sounds sweet to me. It's also an inherently mono effect and we know folks will throw darts but it is what it is. A stereo version would add cost.

Sorry for the long post. Rose is fundamentally different. It's an experiment. It's a left turn. It's different. And, I love it. Now let's see if anyone else cares.