MOSTIK
Mk1

A compact Wi-Fi speaker project from Prague. In Czech, mostík means “a little bridge”.

The name stayed because it describes the work fairly well. Mostik takes music from the network and puts it into a physical thing in the room: birch plywood, an aluminium back, a front knob, a clear green status LED, visible screws where they make sense. Mk1 is still being built. Roon, AirPlay, Lyrion and Bluetooth are the starting set of sources, not a closed list. There is also a separate Roon-only listening mode. The official Mostik software runs from a removable SD card, so the speaker has a recovery path and room for experiments.

Follow the build See current status
MOSTIK Mk1 render with exposed construction lines
MOSTIK Mk1 front render

01

Object

A small speaker I would actually keep in the room.

Mostik began as a practical gap in my own flat. I wanted a compact network speaker that did not feel like a router with drivers attached. It should be quiet visually, easy to live with, and possible to understand once the back comes off.

What it isA compact stereo network speaker for home listening. I am testing it with Roon, AirPlay, Lyrion and Bluetooth now. There is also a Roon-only mode for focused Roon listening, while the source list can still change as Mk1 develops. The system runs from a removable SD card rather than a sealed internal image.
Who it's forPeople who care about how they listen at home, but still want one small object they can put on a shelf without thinking about it all day.
The nameMostík is Czech for “a little bridge”. The metaphor is simple enough: network audio on one side, a wooden and aluminium object on the other.
The lookLow, compact, with visible birch grain and a sandblasted aluminium back panel. One knob on the front and a clear green status LED. The light is part of the identity: simple, visible, and tied to what the speaker is doing.
The long viewMk1 starts as a small numbered run. The cabinet opens, the main parts are documented, and the system lives on a removable SD card. The official Mostik image is the intended experience, but the hardware is not locked to it.
MOSTIK Mk1 construction render

02

Current status

Now it has to become a real box.

The CAD work is close enough that the next useful answers have to come from wood and aluminium, not more renders. The hardware stack is on the bench. The first prototype has to show what the cabinet, port and DSP are actually doing.

Design
Enclosure, internal chambers, port layout, front face and back panel are nearly final in Fusion. The first prototype starts from those calculations, then gets measured and tuned.
Hardware
Pi CM4, HiFiBerry Amp2, Dayton RS100-4 drivers, Meanwell PSU and a Pico-driven knob. This stack is chosen, sourced and working on the bench.
Software
The software is built around local control, source switching and two ways of listening: normal mode with several inputs, and Roon-only mode for using the speaker as a dedicated Roon endpoint. The system image lives on a removable SD card.
DoneEnclosure design in Fusion, hardware stack on the bench, first source tests, control concept, SD-card software path
NextFirst CNC build, acoustic measurements, CamillaDSP tuning, real photographs
Current imagesRenders from the current Mk1 CAD design. Real prototype photos will replace them after the first CNC build.
SizeApproximately 430 × 152 × 200 mm (W × H × D)
MOSTIK driver close-up render

03

Build

I want to be able to open it.

If a driver dies, I do not want the whole speaker to become waste. The cabinet is designed for access. The main pieces are ordinary, documented parts: compute board, amp, drivers, power supply and the small controller behind the knob.

12 mm Baltic birchCNC-milled enclosure with visible grain and natural oil finish.
3 mm sandblasted aluminiumThe back panel holds the connectors, antenna and power entry. Each series can have its own panel.
Dayton Audio RS100-4Two full-range drivers, separate acoustic chambers, bass-reflex tuned by measurement.
Raspberry Pi CM4Runs the local Mostik software stack and the network audio services. The system is kept on a removable SD card, so the speaker can be restored, backed up, or used with another compatible Pi audio image.
HiFiBerry Amp2 + Meanwell PSUA compact Pi amplifier board with a proven, replaceable power supply. I chose this setup because it uses known, reliable parts instead of custom electronics that would be hard to source, explain or service later.
Knob + Pi PicoA separate Pi Pico reads the front knob and turns simple gestures into daily control: volume, play and pause, next and previous track, source switching and Bluetooth pairing. The green front LED and short musical cues give Mostik its own clear feedback language. The Pico is part of the Mostik control system, but it can also be reprogrammed for other uses.

04

Acoustics

Designed first.
Tuned after measuring.

The enclosure is already calculated around the parts I chose: the Dayton drivers, separate chambers, port layout, amplifier and DSP path. That gives the first prototype a serious acoustic starting point. The real tuning comes after the box exists, when I can measure it, see what needs help, and finish the response in CamillaDSP.

01
Build
First CNC and assembly run, based on the chosen drivers, chambers and port layout.
02
Measure
Check the real driver behavior, port response and what the box does in a normal room.
03
Tune
Use CamillaDSP to finish the response around measured behavior, not guesses.
04
Listen
Long sessions in normal rooms. Some decisions only show up after living with it for a while.
MOSTIK rear acoustic render

05

Sources & Control

Sources, local control and a Roon-only mode.

Mostik started from my own need for a small network speaker that behaved well at home. Roon is an important path for me, but Mk1 should not be locked to one ecosystem. Normal mode keeps AirPlay, Lyrion, Bluetooth and future sources available. Roon-only mode is for the opposite use case: a quieter setup where Mostik behaves as a dedicated Roon endpoint and other inputs stay out of the way. Setup, naming and status live in a browser page served by the speaker itself, while the whole system still lives on a removable SD card.

Roon
An important path for home listening. The aim is a stable named zone in a Roon setup, without pretending that every official step is already done.
Roon-only mode
For dedicated Roon listening. Other inputs step aside, and the audio path can stay as direct and predictable as the Mk1 hardware and software allow.
AirPlay
For quick playback from a phone or laptop on the same network.
Lyrion
For people with an existing Lyrion / Logitech Media Server library.
Bluetooth
A local fallback when network playback is inconvenient, or when a guest just wants to connect.
Local control surface
A browser page served by the speaker for setup, naming, status and source visibility. The front knob handles daily use, while the SD-card system keeps recovery and experimentation possible.

The source list is a working set. Normal mode stays open to several inputs. Roon-only mode is there when the speaker should simply behave like a Roon endpoint.

MOSTIK browser interface preview

06

Plan

From CAD
to the first measured unit.

The plan is organized by months, but the work does not happen in neat boxes. Software, hardware and the enclosure keep pulling on each other.

01
Finalize the design
Jan - May 2026
Lock the enclosure in Fusion: proportions, front face, back panel, internal layout and materials.
02
Software and control
Feb - Jun 2026
Browser interface, naming, source handling, knob behavior, SD-card image, update path and playback services.
03
First built prototype
Jun - Jul 2026
CNC the wood, make the baffles and back panel, assemble the first complete unit.
04
Measure and tune
Jul - Aug 2026
Acoustic measurements of the calculated cabinet, CamillaDSP correction and real photos replacing renders.
05
First numbered series
Aug - Sep 2026
Open the first series only after the prototype has been measured, photographed and lived with.
MOSTIK rear panel render

FAQ

Useful details.

A few direct answers for people who are wondering what Mostik is, how finished it is, and where it might fit at home.

What stage is MOSTIK Mk1 in?
Final design in Fusion, hardware on the bench and software in active build. The next public milestone is the first CNC-cut prototype, with measurements and real photos after that.
How does daily control work?
One knob on the front handles volume, play and pause, next and previous track, source switching and Bluetooth pairing. The gestures stay simple: turn, press, double-click, triple-click and hold. Mostik answers with a green LED and short musical cues, designed to be pleasant, recognizable and easy to learn. Setup, source visibility and naming live in a browser page served by the speaker.
Is Mostik only for Roon?
No. Roon is an important use case, but Mk1 is being designed as a small network speaker with several input paths. Roon, AirPlay, Lyrion and Bluetooth are the current starting set, and the list can still change.
Can I run my own software?
The official Mostik image is the main supported path, because it ties together the sources, local UI, DSP, update flow and knob behavior. But the system is on a removable SD card. A technically confident user can keep a Mostik card aside and try another compatible Pi audio setup, such as a user-installed Roon Bridge or RoPieee-style system. The Pico knob is separate from the main Linux system and can be reprogrammed for other uses.
Who's behind this?
Mostik is a one-person project by Jaromír Pesr in Prague. I make films for a living. It started as a network speaker I wanted for my own apartment and slowly turned into something I want to build for other people. The first units will leave Prague signed, numbered and tested by me.
Why so serviceable?
A speaker that lives near books and records should be possible to understand years later. The cabinet opens, the main parts can be replaced, and the system lives on a removable SD card, so recovery and future experiments are realistic.
What is Roon-only mode?
A dedicated listening mode for people who mostly use Roon. In normal mode, Mostik keeps several sources available. In Roon-only mode, the other inputs stay out of the way so the unit behaves more like a clean Roon endpoint. It is a design goal for the product, not a certification claim.
When can I buy one?
The first numbered series is planned after the first prototype is measured, listened to and validated. The form below is only for updates; sales will open later.
Why this exists
Mostik started as a network speaker I wanted for my own apartment, with Roon as one important part of how I listen. I wanted something small enough to keep in the room and honest enough to open later. The name comes from Czech: mostík means “a little bridge”. Mk1 is the first version I want to put on other people's shelves. What comes after should be shaped by the first real units, not by a polished render.

Follow the build

Follow the first build.

The next updates will be the first measured prototype, real photos and notes from living with it.

Prototype list

Get on the list.

I’ll write when there is something concrete to show from the build. That means real photos, measurements, listening notes or news about the first small series. Every note is written by me.

Occasional updates only, tied to real progress on the build.

Direct contact
hi@mostiklabs.com