- In April 2019, I started a thread-based Twitter love letter to my years as an Amiga fan, back in the days when I didn’t have to worry about bills, taxes, and dating apparently. This thread tried to give an overview of demos, modules (the musical kind), and music tools on the Amiga (especially ProTracker, and its inspiration: The Ultimate Soundtracker).
That thread lasted only three days2And 25 or so tweets, in 3 separate threads. ‘cos if it’s easy it ain’t fun., but got me thinking: Where did the author of The Ultimate Soundtracker, Karsten Obarski, get the idea for his paradigm-shifting3Important topics require important-sounding words, mate. tool?
That threw me down a rabbit hole of searches and deleted forum posts and date comparisons and emailing people left and right, trying to answer that one question: When did the « tracker » way of composing music (or, the music sequencer) made the jump from a hardware, physical product to a software product? 4Did I succeed in answering that question in the end? Read on…
- In July 2021, I turned my 3 love-letter threads into a proper blog post, which quite innocently ended with a single5but very lengthy question, which I’ll sum up as this:
« Did step-sequencing really made a single jump from the expensive, Australian-made Fairlight CMI II sampling workstation in 1982, to the cheap, German-made Soundtracker software in 1987, as Wikipedia implies? »6Told you it was lengthy. I already had the answer in several notes, links, and emails. I just needed to write that down. 7Welcome to today, four years after the initial threads and searches, where the present article is finally scratching the surface, yaaaay procrastination (and fatherhood)!
- In September 2021, I started this « Soundtracker origins » series, where I presented the context of the creation of The Ultimate Soundtracker by Karsten Obarski, its demise as a commercial product, its rebirth in a thousand free clones, the vanishing of its creator, and his apparent inspiration: Chris Hülsbeck’s SoundMonitor, in 1986. Getting closer to 1982, woohoo!
- On January 1st, 2023, I published part 2 of my Soundtracker Origins series, where I explored the origins of SoundMonitor, got to interview Chris Hülsbeck himself, and learnt that his inspiration could be8His memory of 1985 is foggy, understandably. I don’t even remember what I had for lunch yesterday, let alone 30 years ago. Probably Nutella crêpes, come to think of it. Steinberg’s MIDI Multitrack Sequencer.
And now, today.
To remind you of the steps to cover, we’re trying to go from this to that.
Steinberg, you say?
In Part 2 of this series, Chris Hülsbeck told me that he remembers using Steinberg’s MIDI Multitrack Sequencer tool on the Commodore 64 computer, around the time he wrote his own tool, Soundmonitor.
Steinberg9By the way, if you are germanophone, please excuse the sad pun in the title of this present article…? In 2023, they are one of the biggest musical software/hardware company, with industry-defining contributions such as Cubase of course, and the VST plugin interface, amongst other inventions.
In terms of well-known names for professional and amateur studio musicians, they’re up there with Digidesign/Avid (makers of Pro Tools) and Ableton (makers of Ableton Live).
But 40 years ago, in 1983, they were three, working from a living room in Hamburg: Karl « Charlie » Steinberg (31), Manfred « Manne » Rürup (32), and Nicole Rürup, Manfred’s wife (age unknown).
At the time, Karl was a musician and audio engineer, and Manfred was a musician and a salesman at a music shop. In the early days of the Steinberg company10Thus named because « Rürup » didn’t sound international enough to them., Nicole took care of design and manuals11« She’s very good at graphics and so she did some of the company adverts and helped produce the manuals. We had this little Roland computer plotter and we did our first manuals with that. » (source).
We’re lucky to have several early interviews online.
Let’s start with Manfred:
Interviewer: « In the 80s you formed a new wave project called Direktion and released ‘Jeder Tag Wunderbar’ in 1982.«
(…) I went to a studio on the countryside, called Delta-Studio. The studio was willing to take the risk of producing my songs. So I went into the recording room to meet the engineer and there he was: Karl Steinberg. It was one of these moments where two souls meet for the first time.
At that time, 1980, I was part time working in a keyboard shop, at Amptown in Hamburg which gave me access to the latest in keyboards and samplers and to the MIDI12The MIDI (Musical Instrument Digital Interface) protocol makes it easy to transmit musical data between digital devices like keyboards and computers. Instead of sending sound files, it transmits event messages such as pitch, velocity, and timing. Upon its release, it revolutionized the music industry by enabling seamless interaction between digital musical instruments and computers, profoundly influencing the creation, recording, and production of music. protocol which was released in 1982 I think13Ackchyually, 1983. *tips fedora*..from the excellent It’s Psychedelic Baby magazine interview, May 2021.
I was always interested in electronics; in 1976 I built an analogue sequencer with sliders, but you could also speed it up and use it as a waveform generator. However, my soldering was never too good. Then I became a studio engineer, and that’s when I met Manfred Rürup. We soon discovered that we thought on the same wavelength, and because Manfred was working a lot with keyboards, we always had access to the latest gear.
One day [Manfred] gave me some sheets of paper which had MIDI data formats on them. As I had already been working with Sinclair computers – ZX81 etc. – I suggested to him that it would be very easy for me to write a MIDI program. So I used a Commodore 64 computer to develop it, which Manfred had at home, and then we just started to sell it to other people we knew.
I used to work at Manfred’s home. That’s where we started building the little MIDI interfaces which I developed and even soldered up all by myself. They were the very first things we did there.from the Sound on Sound interview, July 1986.
Says Manfred14And no, no trace of an interview of Nicole online.:
At that time I played with Inga Rumpf and thus had the opportunity to visit the music dealers in the morning with my portable SX6415The portable version of the C64. and to present our system to them. However, the interest was not very great. But we were only a three-man company: Charly, my wife and I, and when you sell ten MIDI packages, that’s « big business » (laughter).Google-translated from the TOS Magazin interview, January 1992.
I’m pretty sure I’m missing on a LOT of interviews just because I don’t know the right German keywords to search…
Musicians writing software for musicians… Kinda reminds me of both Karsten Obarski (in part 1 of this series) and Chris Hülsbeck (in part 2), who each saw a personal need and successfully scratched an itch that, hitherto unbeknownst16I warned you there’d be important-sounding words. So there. to them, was common to all musicians.
Not much remains online of their MIDI Multitrack Sequencer (1984), not even a screen capture17Unless you’re like me and you went down that same rabbit hole as I did, and came back with this.. But that’s possibly because that tool was quickly surpassed by Steinberg’s next creation, Pro-16, another MIDI sequencer which quickly gained quite a bit of success from the moment it was released in 1985.
There are many different software sequencers on the market for the CBM 6418Commodore Business Machine 64. That’s a mouthful. and they all have something to offer, but none of them are as complete and easy to use as this one. Well done Steinberg: 10 out of 10!A review of Steinberg Pro16 MIDI Sequencer, aptly titled « The Professional’s Choice« , in Sound on Sound (April 1986).
You can record the notes of a MIDI keyboard, track by track, and replay all tracks in parallel, up to 16 tracks, even with effects like the pitch wheel.
To our 2023 eyes, it looks pretty basic and clunky, but at the times, it was an eye-opener on the possibilities offered to everyone, professionals and hobbyists alike.
Alright, I hear you, « Enough already with the History lesson! »
Did I succeed in contacting them?
My attempts at talking with « those who know »
I agree, this subtitle does not bode well…
Well, I figured I would never be able to contact neither of the Steinberg co-founders directly, so I tried to go the official route:
No answer. Figures.
Let’s get personal, then!
Karl « Charlie » Steinberg has an old-school online presence, where he writes about current projects — ever since he sold Steinberg to Pinnacle in 2003, I suppose he has a lot more free time on his hands. The website doesn’t look quite up-to-date, but he seems to enjoy being the keyboardist for the German band Stier.
Sadly, I cannot find a contact email on his website — I guess we can understand that he doesn’t want to be too easy to contact.
I couldn’t find an online presence for Manfred Rürup, nor Nicole Rürup19Weeeeeellllll, that’s not quite right. It’s more « I couldn’t find a readily accessible online presence », really. As a matter of fact, there is a « Manfred Rürup, Supervisory Board Member at Ableton » (yes, Ableton, not Steinberg) on LinkedIn who looks an awful lot like an older version of the hippie guy from above. But I couldn’t message him directly because I had to be a LinkedIn Premium member to do so, and, well, I guess I decided not to bother him, when I started this research project back in 2019?. Damn.
Where to look?
With their early success and growing projects, Karl Steinberg and the Rürups started hiring employees, and were soon joined by musician and software developer Werner Kracht in 1985.
Mr. Kracht worked for Steinberg on a couple of educational products, then in 1986 he developed the successor to Pro-16, called Pro-24, for the Atari ST20A machine that comes with a built-in MIDI interface: no more custom dongle to bundle with the software! To this day, the Atari ST remains a very important machine for musicians, thanks to this hardware choice by Atari. 21But Amiga roulaize quand même, hein..
Herr Kracht wrote Pro-24 on the Atari ST pretty much on his own, because Herr Steinberg was very busy producing various OEM versions of Pro-16 for different hardware manufacturers — it was a real money-maker for them at the time.
Pro-24 was the first music software written for the Atari. It had quite an impact on the industry as a whole.
That first step on the Atari ST market was key for the Steinberg business, as it would lead three years later to the creation of Cubase in 1989 — mostly created by Mr. Kracht and a small team, as I understand.
Werner Kracht does have a nice online presence, with extensive information about his musical whereabouts — and a long, informative and ultimately bittersweet write-up of his programming endeavors and his relationship with the Steinberg company as a contractor for 25 years (written in German; Google Translate link).
Of note, there is also this recent in-depth video interview (which, yes, I watched from beginning to end). He also published several videos from his early work at Steinberg.
I found his email address on one of the pages on his website.
So let’s contact Mr. Kracht!
Well, that didn’t pay off.
My Steinberg early-employees lead dries up…
In order to get first-hand information, I need to contact Mr Steinberg himself, it seems. An impossible task, I suppose: finding the direct contact address of the former CEO of one of the greatest music company there is!
There’s this one webpage.
Where… Maybe? It doesn’t seem to be directly tied to… but we never know… doesn’t hurt to try I guess?
…and, what do you know, the very next day:
My friends, two years after I started this on-and-off quest, I was in direct contact with Karl Steinberg.
Let’s breathe a little.
Interviewing Karl Steinberg
Mr Steinberg (I’ll call him Karl from there on22‘cos after 5 emails I think it’s fair of me to call him a friend.) seemed genuinely interested in digging in his memories (and even his attic!) to retrieve memories, send me screenshots and pictures, and generally answer my questions.
So, let’s copy-paste from those emails, shall we?
XB: By email, Mr. Hülsbeck told me that his « inspiration for the note representation came from an early C64 midi sequencer by Steinberg, which didn’t display notes as symbols, but as a list of single letter note name, an optional ‘sharp’ symbol if needed and a number for the octave ». He later wrote that his inspiration was the « MIDI Multitrack Sequenzer » from Steinberg.
KS: As nice as it sounds, I cannot confirm that.
Our first C64 Program was indeed named « Midi Multitrack Sequencer », little known, and so it’s hard to even find a picture (see below).
It already had the « Songtable » which was later continued in its successor, Pro 16.
But there was no MIDI editing with Midi Multitrack Sequencer. Pro 16 later featured a keyroll editor (quite remarkable for that time if I may say so). Midi Multitrack Sequencer had a quantize feature24The ability to move notes around on the playing grid, in order to adjust timing or to correct imperfections., which would also allow for double- or half-speed playback, and transpose25The ability to change the pitch of a note, to adjust melody or, again, to correct imperfections — a predecessor to Auto-Tune.; it also even featured sync (Roland) via a proprietary sync interface
I assume you (or Chris) are referring to JMS (Jellinghaus Music Systems) Multitrack Composer (see picture).
Jellinghaus had a MIDI Interface first which was quite similar to ours (UART), and added that list-based sequencer software which is the first I can remember. Given that it was released around 1984, we were quite fast to create a sequencer with « UI » 🙂Private e-mail interview from April 202126Yes, again, I’m that late in publishing this..
🚨Alert, alert, a new player has entered the game! 🚨
Karl here mentions Jellinghaus, a company I have never heard of before! And indeed, seeing from the picture he sent me, their tool does seem to include « text-based » notes that musicians will see again appear in Soundmonitor and, eventually, The Ultimate Soundtracker and all of its clones.
Looks like I’m gonna have to dig up information about that Jellinghaus Music Systems!
However, Karl did send me this picture of Pro 16’s Key Editor, which clearly features « textual » notes on the left column: F5, D5, E4, with a # for black keys.
So, could Chris Hülsbeck really have been inspired by Steinberg’s Pro 16 rather than their Midi Multitrack Sequencer — or even the Jellinghaus system?
I asked Chris directly, sending him the Jellinghaus and Pro-16 images above:
I’m pretty sure it was the MIDI Multitrack Sequencer, but there are no screenshots online from the pattern page and as far as I know the software doesn’t run without the Steinberg Midi Interface hardware… so it may have been the Pro-16 too… it’s been such a long time ago! 😉From private e-mail exchange from September 2023.
I further sent him the Multitrack Sequencer single screen that Karl sent me.
Yes, then the pattern page may have been from Pro-16…
Maybe I was also dreaming about a pattern edit page… maybe they did not even have one… the color scheme and blinking cursor definitely more resembles the Pro-16, but everything is so hazy at this point… 😉From private e-mail exchange from September 2023.
So, not quite a definitive answer there. Since all of this happened some 40 years ago, I can understand the foggy memories 🙂
But since Steinberg’s Pro-16 was being reviewed by a UK magazine in February 1986, and Chris Hülsbeck wrote his own Soundmonitor in the Summer of 1986, then it could definitely still be a match — although quite a tight one, I’ll admit.
Anyway, that Jellinghaus thing is an interesting story in itself, but that’s for another article; let’s continue talking with Karl Steinberg about the early Steinberg history.
XB: [Were you] the sole developer of the C64 Multitrack Recorder and Pro-16?
KS: Yes, I pretty much developed those two programs by myself. Then Pro 24 followed on the Amiga, which was mostly done by Mr. Werner Kracht, myself adding some « low-level » stuff. There was also a version of Pro 16 for the Mac II if I remember correctly, ported by somebody else whose name I forgot.
XB: [What were your inspirations for these tools?]
KS: My inspirations were just to see that it was possible; we only just had started to deal with computers. We (Manfred Ruerup, co-founder, and me) were busy in a decent studio (Delta Studios Wilster), Manfred sold keyboards at Amptown Hamburg and always brought in the latest gear, so there was a lot of inspiration from that end. Also I guess sequential drumtracks was inspiring quantize and pattern concepts.Adapted from private e-mail interview from April 2021.
Later we dealt with samplers, [Fairlight] CMI, [Sequential] Prophet, etc., triggered everything with everything via the studio patchbay and so forth.
🚨Alert, alert, we have inspiration! 🚨
Karl mentions « sequential drumtracks », which I assume means « drum machines » — but he could also be talking specifically about the DrumTraks drum machine, released in 1983 by the Sequential company (hence, Sequential DrumTraks, with proper capitalization!) — whose CEO, the late Dave Smith (archive), co-authored in 1982 the MIDI specification itself.
Again, a story for another article — but let’s keep in mind that « sequences » and « patterns » were nothing new in the 1983 world of digital music28Although the word « pattern » appears only once in the MIDI specification. But they might be using synonyms?.
Let’s see his other answers.
XB: I’d like to find out whether [you] invented the whole « pattern of notes » representation, or if [you] got inspired from somewhere else, like a drum machine or the famous Fairlight CMI Series II.
KS: See [my previous answer] 🙂
Not sure what you mean by « pattern of notes »; list-based sequencers like the JMS mentioned above, were probably the first to allow MIDI editing, and that was the obvious choice for computer-based systems as a first step.
Not sure if there were piano-roll type MIDI editors before the Pro 16 addition – it also even featured a score editor later on.
As for inspirations, I’m certain that it was not only me who was inspired by drum machines. Those were based on patterns and « songtables » (chain of patterns) and featured MIDI, and were the first devices to combine this, so it was kinda obvious to start off from that ground.
Trackers are more closely related to « list-based » sequencers which in turn were the obvious choice from a (pre-)80s computer point of view. There was practically no graphics until Apple, and then Commodore, and then Amiga and many others to follow, and until then you’d have to use computers for music like a typewriter.
One more note…nothing I say here is proven truth; memories are often changing over time, and I’m particularly bad at this 🙂Ibid.
As I wrote to Karl, his answers brought me new clues and new directions to find when the « jump » of the sequencer idea from hardware to software happened.
I’m closing this interview with the following: a picture of the Card 32, the MIDI interface that Karl created along with Pro-16, followed by his very own comment on it:
As I understand, Pro-16 was not sold as a software on a floppy disk or cassette: it was sold as part of the EPROM of the MIDI interface itself, thus bypassing any other system request29I hear it’s called a fast loader.! Incredible piece of equipment…
Oh well, let’s drop a couple more pics, just because I can 🙂
And now I can be satisfied in knowing I gave you everything I know 🙂
It’s interesting in that it seems to have walked parallel paths:
- The people behind the Fairlight CMI Series II’s « Page R » feature where inspired by a drum machine30More on that in the next part of the series! — but this was more about step sequencing, so that did not directly inspire trackers such as the Amiga Soundtracker.
- And now, it seems the « Commodore line » follows this path: Jellinghaus’ Multitrack Composer ➡️ Steinberg’s MIDI Multitrack Sequencer ➡️ Chris Hülsbeck’s Soundmonitor ➡️ Karsten Obarski’s Ultimate Soundtracker — each taking inspiration from the previous one, and adding a significant progress to the initial idea.
Their common aspect: describing notes not as in a graphical representation, like the Fairlight CMI II’s Page R did31You know, with « ♪ » and « ♫ » and all that jazz., but as « text-based » sequences, such A-3, B-5, F#232And no, « X Æ A-12 » doesn’t mean that that poor child has an A at the 12th octave in his name., etc.
Indeed, it looks like the pioneers at the time were quite fast in taking inspiration and improving upon each other’s ideas! What a time it must have been to be in that field!
Now, I have to find out the ones who created the JMS Multitrack Composer — and it seems I’m getting close, as a quick search seems to indicate that they were hardware producers mainly.
So, there ends an important milestone in my little quest! 🙂
The next parts will focus on each of the two parallel paths that I highlighted above:
- The Fairlight CMI path: finding out how they came up with the idea for their Page R sequencer.
- The « Commodore » path, going down the JMS rabbit hole, and their Multitrack Composer.
Will there be more parts? Who knows? I sure don’t!
You thought it was over, right?
That would be too easy…
Get ready foooooor: an 🤘Á̸͈̣̉͆͊̈́̚͝Ḑ̵̧͕͙̀̅̽̎͊͂̿̏̀͒͛̽͘̕͠D̵̢̥̩̫͈̠̘̫̫͎̰̯͈̘̉͌Ḙ̵̱̖̺̜̼̬̰̟͒̐͒̇̿̌̂̔̊̕͘͘N̷̢̯̜̈́́̿̀̄̀̍͑͌̇͗̓̕̚D̶̹̪̈́̿͛̃̏̔̔͋͑́Ų̷̳̱̮͍̪̬͍̥͓̺̯͉͑͐̐M̵̨̢͈̐͠!!!🤘
Addendum: Manfred Rürup’s take
Since 2023 is definitely not like 201933And I’ve had to take a LinkedIn Premium account anyway, for training reasons., I’ve decided to approach Mr. Rürup, in order to have his own take on the whole thing, and possibly bring a different perspective.
So here goes, a short interview!
XB: Reading various early interviews (notably this one from 1986 and this one from 1992), it sounds like that Nicole was the designer, Karl was the technician and you were the marketing/salesman. Was that as binary as that, or did you share duties?
MR: That is correct.
Nicole did not design UI or anything like that. She did all the print advertisements and the manuals.Private e-mail interview from September 2023.
As a technical writer myself, I can tell you that just producing the documentation for this is no small taks — but it seems she did it « with an electric typing machine, all the illustrations are ASCII art (!!!) and all the binding and transparent plastic cover are typical office stationary from the ’80s« , as per this eBay UK listing, which I’m taking the image below from.
So, yeah, quite a task in itself!
XB: I mention Nicole, your wife, because she was part of the initial team, as I understand, but I hardly see her name in interviews — most of the time, she’s there as « support », or as manual and adverts designer. How did her role grow with the success of the company? Or did she move to another line of work / company eventually?
MR: She continued to do advertisements and graphics and the manuals. A lot to do, as the software became very complex and so the manuals [grew] bigger and bigger.Ibid.
XB: It seems that Steinberg’s very first product was the MIDI Multitrack Sequencer. Do you remember if it was influenced by an existing product, hardware or software? What were the competitors at the time in the MIDI market?
MR: The MIDI Multitrack Sequencer was a single page product, because we preferred one page and no menus which lead to another page. I think it was pretty unique.Ibid.
XB: How many copies do you think were sold before you moved on to bigger things? This article says « fewer than 50 copies », and in this one you are quoted as saying « when you sell ten MIDI packages, that’s « big business » (laughter) ». Is the real number in between?
MR: The real number is probably around 50 copies.Ibid.
Remember the quote from the interview earlier in this article? « When you sell ten MIDI packages, that’s big business (laughter) ». Well, I suppose selling 5 times above your expectations is a sure sign that your little hobby is onto something, and you should push forward. I’m glad they did!
XB: Who did you mostly sell it to? Did it spread outside of Hamburg, to your knowledge?
MR: I think all over Germany and Austria.Ibid.
Chris Hüelsbeck was born in Kassel (300 km from Hamburg) and worked for Rainbow Arts in Gütersloh (267 km from Hamburg), so yeah, I suppose he could have found a copy a Steinberg’s early tools at the time.
Funny thing is: both roads from Kassel and Gütersloh to Hamburg pass through Hanover — which is where the CeBIT, the « largest and most internationally representative computer expo » at the time, happened from 1970 to 2018. So information and ideas certainly spread around from this epicenter 🙂
XB: Mr. Steinberg told me about the Jellinghaus Multitrack Composer. Do you have recollection of that tool, of the Jellinghaus company itself, or even of their C64 development team?
MR: What do you mean by « recollection »? Never met them [then nor] since then.Ibid.
I had to try…
XB: My understanding is that, after the MIDI Multitrack Sequencer, there were a few OEM product and the Pro-16, made by Mr. Steinberg on C64, then Pro-24, made mainly by Mr. Kracht on Atari. Eventually it all lead to Cubase on the Atari, but who’s was the main programmer of Cubit/Cubase 1.0, Mr. Steinberg or Mr. Kracht (or someone else)?
MR: Cubit/Cubase was a team-work of Werner Kracht, Wolfgang Kundrus, Stefan Scheffler, Michael Michaelis and Charly Steinberg.Ibid.
Many names, which I could interview, but really, it’s time for this article to be released.
For those interested, here is an in-depth and recent video interview of Wolfgang Kundrus; and Michael Michaelis has a lot of opinions and shares them on his website (en German).
Also, did he forget about Chris Mercer?
XB: It seems to me that Mr. Steinberg was mostly working on M-ROS and low-level stuff, while Kracht (and a team?) worked on the main interface. Is that right?
MR: The architecture and UI idea came from Wolfgang Kundrus, Werner Kracht did the data-storage and handling, Charly Steinberg did M-ROS and other things, Michael Michaelis did work for the scoring and Stefan Scheffler did the integration of the User-Interface funktions.Ibid.
I have to say a word about M-ROS, for the sake of completeness.
The MIDI Real-time Operating System (M-ROS) was a very innovative alternative operating system, which worked on several platforms (Atari, Apple), and brought true multitasking to systems that weren’t quite able to do that by themselves. Since MIDI meant having different tools working together in (hopefully) real time, M-ROS turned to be essential to the success of that protocol — provided that those tools were written for M-ROS.
It eventually lead to the ReWire protocol, conceived by Propellerhead (makers of Reason) and Steinberg, which was very much used by most other DAWs from 1998 to 2020.
So, no small feat for Karl to be so prescient and technical in 1989!
XB: Did you yourself do any programming on the Steinberg tools?
MR: No, not a single line.Ibid.
I suppose Manfred is great with a piano keyboard, less so with a computer one 🙂
And that’s it, my friends.
Let’s close this chapter about Steinberg by remembering that they were first and foremost musicians who were passionate about music and helping other musicians achieve their dream!
Find a copy of this home-made album to convince yourself 🙂
Other articles in this series:
- Soundtracking sur Amiga : passion, explications et exemples — The Twitter thread that started it all (in French).
- Soundtracker origins, part 1: Where in the World is Karsten Obarski? — About Karsten Obarski, author of The Ultimate Soundtracker.
- Soundtracker origins, part 2: Welcome to Turrican, aah hahahaha — About Chris Hülsbeck, author of Soundmonitor.
- Soundtracker origins, part 3: Facing a stone mountain — About Karl Steinberg, author of MIDI Multitrack Sequencer.