Work in Progress: LinnStrument Backpack

[John the Savage]

I wish I could do 5 modulators: velocity, envelope, pressure, LFO, random/Y. I need to pick one to cut. I might be able to cheat by making a "macro modulator" that mixes the Z signal with an envelope. What do you think are the most important modulators for Linny patch design?

If you have to cut a modulator from the list above, I would suggest that you could do without an LFO. Technically, when playing the LinnStrument, your fingers are the most effective LFO. To that end, one might argue that the envelope is redundant for the same reason, but using pressure to emulate an envelope response doesn't always work as needed. And if you do go with a "macro modulator" of sorts, a Global LFO is a common mod source on most poly synths.

Anyway, just my two cents worth...

Cheers!

[TigerBalm]

My work on this got paused for the past 6 months as work got really intense, but I'll be diving back in soon. Here's some sounds I recorded last night. The patch is a square wave going into a low pass filter modulated by the Z pressure. There is a tiny bit of attack and release on the volume envelope to minimize clicks.

[MilesParker]

I'd love to have just a "side car" like you have there, to put different projects within. Ideally, it would have pass throughs for Linn IO ports, a cover and match overall look. It's the kind of thing I'd be willing to pay real money for if it was nicely implemented. It could be used for RPi based project but a narrower version would be useful even for people who simply wanted a place to put a battery and widi or mount iOS device.

(One thought I had is that for stability you could make longer ears that would attach to the sidecar -- I'm just not sure how well the guitar strap holes alone would stand up to the torsional force from side car, though that would mean you couldn't easily remove sidecar when you wanted to use the Linnstrument in conventional mode.)

[Roger_Linn]

Hi Miles,

I've considered something like that but it's tricky figuring out the form factor, and expensive in consideration of the sheet metal and wood. I had thought of a iPhone slot in the sheet metal but that wouldn't work for anything else.

Any thoughts?

[t-IB]

Hi Miles,

I've considered something like that but it's tricky figuring out the form factor, and expensive in consideration of the sheet metal and wood. I had thought of a iPhone slot in the sheet metal but that wouldn't work for anything else.

Any thoughts?

Didn't someone do a 3d printed iPad holder (edit: that bolts in place of the rear wood bit)? Perhaps an alternative front and back attachment incorporating a holder could work?


I love the idea of an extender, or even just a dongle to pair up, incorporating some of those ideas you talked about in another thread, in terms of having a musically focussed sound generator.

[Equiton]

FYI, here's an early LinnStrument design concept. it's difficult to equal the synthesis bang-for-the-buck that an iPhone delivers. Unfortunately Apple changes the size and shape every year. Then there's the problem of your LinnStrument occasionally ringing.
( ͡° ͜ʖ ͡°)

I suppose some sort of 'phone' holder that attaches to the guitar strap points might be an idea for someone.

Though I did think that an iPad in some sort of holder would work too.

[MilesParker]

What I was thinking is that it would simply extend the Linnstrument depth and width dimension exactly. Perhaps if manufacturing costs were reasonable there could be different lengths (or is that width? but hopefully it's clear what I mean!), i.e. perhaps:

1a) One around 6cm for people who just want a convenient place to mount powerbanks and other connections. Top would be easily openable / modifiable maybe with a pass through on top for USB/lightning and some kind of clip for devices. (Could include multiple top plates perhaps for different use cases or if a user like me put a hole in the wrong place.) Side pass throughs for the current connections with a power splitter to attach power bank. (And I could do without passthrough if the thing were easily detachable, as this would be supporting the mobile use case only.)
1a.5) As a variation, even a simple tray with edges would solve the most immediate issues for me!
1b) A full boat version might include the powerbank (5000 Mah or so) and perhaps a few extra assignable midi controller knobs/switches as well as (key) a WIDI board, creating a fully self-contained controller. Again it might include pass throughs for USB computer / power bank charging / midi, etc.. or if detachable could forgo passthroughs and just have a single power bank charge port. That seems reasonable because it would only be used for stand-alone case.

2a) Another around 12-14cm to serve as a generic project box which I imagine would be just deep enough for a raspberry pi or custom board like OP's.
2b) Assuming Surge XT is validated for this (Paul has latest build up and running now) full boat version might include the RPi itself as well as a few knob controllers and some kind of simple screen for selecting patches and setting macro values as well as power bank. Surge and associated software would come preloaded. Full pass throughs on this one, with additional ports from RPi for sd card, headphone and (balanced?) audio out. Hey, perhaps even include a small speaker! (Seems silly maybe, but people like them on Volcas and Reface.)

In all cases I can see costs being considerable, but low at least compared to the cost of developing an entirely new device, but obv Roger would know a lot better! For me, a no brainer price point would be 1a) $100, 1a.5) $50, 1b) $200+, 2) $150, 2b) $500+ (USD) depending on feature set, but really the value for convenience would be worth more.

No experience in manufacturing or marketing, but in addition to a modest extra profit center and perhaps a significant new product for 2b, I really think this would drive adoption for Linnstrument. There are a lot of tinkerers out there (1 and 2 a), having a fully standalone wireless option is sweet (1b) but I think the biggest potential is the many people who want a device they can just play (2b).

[MilesParker]

Didn't someone do a 3d printed iPad holder (edit: that bolts in place of the rear wood bit)? Perhaps an alternative front and back attachment incorporating a holder could work?

Yes, that was Geert (Linnstrument programmer). Personally it isn't the solution for me because it requires the cable running under Linnstrument and it doesn't give me anywhere convenient for WIDI. Easier for me to just try to figure out somewhere to anchor a very shallow PB and WIDI UHost (which is tiny).

https://shop.uwyn.com/products/linnstru ... ack-holder

[Roger_Linn]

I like the idea of a chassis extension containing a low-power R-PI running Surge XT. I'd dig into this in the coming weeks.

[FranklyFlawless]

The Zynthian may be a candidate for inclusion in the chassis extension. It had compatibility for Surge until it was updated to Surge XT. It uses a Rasperry Pi 4, and does not include a battery or speakers.

https://zynthian.org/

[John the Savage]

Volca speakers... Haha... Tragic.

Interesting ideas otherwise.

Cheers!

[MilesParker]

I like the idea of a chassis extension containing a low-power R-PI running Surge XT. I'd dig into this in the coming weeks.

Cool, I volunteer to alpha test. I'm guessing the biggest issue would be just cramming everything in efficiently and heat management.

The Zynthian may be a candidate for inclusion in the chassis extension. It had compatibility for Surge until it was updated to Surge XT. It uses a Rasperry Pi 4, and does not include a battery or speakers.

Yep, I’ve been looking into this closely in last week. The good is that it already has everything baked in on hardware side, ports, knobs, screen, ADAC, etc… the bad is that it no longer supports Surge .. it uses LV2 plugin format and Surge team reports that the build they do have is full of bugs, not sure if that’s the LV2 side or the integration.

It also isn’t quite the right form factor for what we are contemplating, though it could serve as a great testbed, i.e. drop the Zynthian software and just install Surge XT … but you would have to write some kind of layer to work well on the small screen and with knobs, but that’s exactly the work you’d have to do to make an embedded Surge anyway. I thought about doing just that, but can’t justify dropping $500 on an experiment.

The kit hasn't been available for a very long time, but is back up on their site now.

When devs tested Surge XT on RPi 4 they said that it worked well on some patches but gets hung up on some of the more complex filters (i.e. ladder OB-Xd), effects (Tape, Spring, ..) and oscillators (Modern & Twist). So you would have to curate the patches included to ensure you weren’t hitting a wall, but in my experience you can get very good sound without them - I don’t think any of my patches use any of those.

Volca speakers... Haha... Tragic.

Not wedded to this hahah, and haven’t used the Volca, but getting a Reface for kids and I hear the speakers are just passable enough to make it workable for grabbing and playing, which is all they would have to do; just be loud and clear enough to practice with — sometimes it’s nice not having to put headphones on. (But waaaaay down list of priorities.)

[MilesParker]

Until Roger gets around to creating the ultimate battery / bt midi side car, I wanted to share a very sophisticated integration. I did hesitate to share it because I worry about protecting the valuable IP embedded therein -- I spent over a minute conceptualizing it and at least 2 in the pilot implementation. I trust people on this forum will not share this elsewhere.

Cerealy though, this was made possible by a legitimately useful find. A couple of the usual suspects on Amazon sell "ultra thin" 5000Mah battery packs that are quite light and wide and flat so there is a nice overlap with surface of Linnstrument -- this wouldn't work with a 10000Mah, guess how I know, but the Linnstrument draw is so low that the 5000 lasts for hours. As the WIDI jack is also very light, the package is more secure than it looks. (Though I have since iterated on the design by adding a second (!) elastic band around the Linnstrument.) A nice aspect of the battery is that it has a single very short integrated USB-C cord. That together with the shortest ISB-C cable I could find and a UCB-B adapter made it quite compact. Honestly, I find that it is cables that are the most annoying aspect of getting this stuff to fit.

Design Alternatives considered were affixing some kind of clip to the surface of the panel or perhaps using some kind of sticky putty like folks use to put wall hangings up, but I didn't want to risk marring the Linnstrument surface. I'm still trying to figure out a simple way to utilize the guitar strap screw holes to attach a bracket (Geert's bracket isn't for me as it requires snaking a cable around, and figuring out steps for designing my own 3d printed version prob. isn't a good use of time for me.)

https://www.amazon.ca/gp/product/B093GK ... UTF8&psc=1

[John the Savage]

I think Velcro is the epiphany you're soon to have.

Cheers!

[MilesParker]

I think Velcro is the epiphany you're soon to have.

Velcro, I feel like I've heard about that advanced technology somewhere... However, I do worry that if I put it on front panel it might damage the screen printing on surface when I pull it back off so was looking for a completely reversible "solution".

Edit: But hey, I guess I could velcro it to the side!