«Lira» geometry
A curved section with a flat baffle and an elliptical back. It removes parallel walls, spreads the internal resonant modes and breaks up standing waves.
Prototype in development
427 interestedOpus I
A two-way loudspeaker built on one simple idea: put acoustic behaviour ahead of what mass production allows.
Drivers byBeymaKeep me posted
Inside the model
Interact with the Opus using your mouse
This is the actual CAD model the workshop DXFs come from: 120 parts, each with its place and its assembly order. Spin it, open it step by step and tap any part to see what it does and why it matters for the sound.
Project status
Where the Opus I stands today
01Concept and acoustic designComplete
Deciding what the loudspeaker had to get right before drawing anything, choosing the drivers and taking the system into simulation.
Defining the project4/4
- Design goals: minimum distortion and progressive directivityDone
- Review of the technical literature (AES, JAES, Toole and Olive, Linkwitz, Geddes, Klippel)Done
- Choosing the configuration: a two-way bass-reflex bookshelfDone
- Deciding on the kit format as the philosophy of the projectDone
Choosing the drivers4/4
- Comparison of manufacturers and rangesDone
- Choosing the Beyma NMF series: 8NMFW woofer and T25M tweeterDone
- Contact with Beyma engineering and validation of the approachDone
- Transferring the Thiele-Small parameters from the datasheetsDone
Electroacoustic simulation4/4
- Modelling the cabinet and calculating the internal volumeDone
- Calculating the bass-reflex port tuningDone
- Study of baffle diffraction and the baffle stepDone
- Simulation project set up with the real woofer impedanceDone
02The «Lira» cabinet16 of 17
The cabinet: curved geometry with no parallel walls, a 40 mm laminated body and every manufacturing drawing generated from a parametric 3D model.
Geometry4/4
- Curved section with a flat baffle and an elliptical backDone
- Removal of the internal parallel wallsDone
- Rebates so the drivers sit flush with the baffleDone
- Bass-reflex port milled into the wooden slices themselvesDone
Laminated construction4/4
- Stacking the 22 body slicesDone
- Resulting walls 40 mm thickDone
- Vertical compression with four M8 threaded rodsDone
- Captive hex nut in the bottom plate so the rod cannot turnDone
3D modelling and manufacturing drawings5/5
- Parametric 3D model of the whole cabinetDone
- Numerical verification of volume and tuning on the modelDone
- Slice-by-slice breakdown, numberedDone
- Generation of the full set of CNC cutting filesDone
- Renders and previews of the assembled cabinetDone
Construction details3/4
- Custom rear terminal plate, integrated into the curve of the cabinetDone
- 3 mm aluminium top plate recessed into the topDone
- Bolted, removable baffle with a butyl sealDone
- Final engraving of the top plateIn progress
03Crossover22 of 24
Matching the crossover to the Beyma drivers to get everything out of them, settling the components and taking it from schematic to manufactured board.
Crossover design6/6
- Fourth-order low-pass for the wooferDone
- Zobel network for impedance compensationDone
- Second-order high-pass for the tweeterDone
- Notch filter to smooth the tweeter peakDone
- L-pad attenuator with a bypass on the top octaveDone
- Schematic validated by Beyma engineeringDone
Components and suppliers6/6
- Air-core coils, with no core that can saturateDone
- Jantzen Audio polypropylene capacitors and resistorsDone
- Dayton Audio main coil and binding postsDone
- Supplier settled: distribution from the Netherlands (SoundImports)Done
- Production prices settled for the first seriesDone
- Bill of materials published openlyDone
Board engineering6/7
- KiCad schematic, passing electrical checks with no errorsDone
- Wiring checked point by pointDone
- Board shaped like the lyre outline, so it fits through the woofer cutoutDone
- Coils mounted on edge to avoid magnetic coupling between themDone
- Final boards received from the factory: 1.6 mm FR4 with 2 oz copper, silkscreened with every component footprintNewDone
- Full-size check with the components laid on the printed boardIn progress
- Seven mounting points verified against the cabinet woodDone
Assembly and validation4/5
- Crossover assembled and values checked part by partDone
- Bi-amping jumpers verifiedDone
- First listening session with the final crossoverDone
- Crossover assembly document writtenDone
- Fine adjustment of the L-pad and polarity after the final measurementsTo do
04Prototypes and iteration17 of 20
Build, listen, write down everything that did not fit and draw it again. That is where the current design came from, now in high-precision machining.
First prototype in the home workshop4/4
- Gluing the laminated bodyDone
- Machining the baffle and the driver rebatesDone
- Fitting the drivers and the internal wiringDone
- First listening session with the complete systemDone
Design iteration and improvements7/7
- Correcting the gluing tolerances that threw the baffle out of squareDone
- Port redesigned as a through cut, cleaner and more robustDone
- Rod system solved: they neither turn nor split the woodDone
- Internal volume and tuning adjusted on the real modelDone
- Baffle with threaded inserts instead of gluedDone
- Materials and fasteners optimisedDone
- Greater manufacturing precision in the cutting setDone
Assembly testing and validation3/3
- Numbered parts that only fit one wayDone
- Timed build: about two hours per pair of cabinetsDone
- Confirmation that no special tools are neededDone
HDF prototype with high-precision CNC3/6
- Workshop chosen: Nord Taller, digital craftsmen in Vilafranca del PenedèsNewDone
- Board change: from MDF to HDFDone
- Final cutting files prepared and deliveredDone
- Machining the partsIn progress
- Dimensional check and prototype assemblyTo do
- Listening to and validating the final prototypeTo do
05Measurements and acoustic validation7 of 11
The first measurements are done and published. What is missing is someone outside, with an anechoic chamber, confirming them.
Preliminary measurements6/6
- Woofer impedance in free air, in a sealed box and with the port openDone
- Reading the real port tuning off the impedance curveDone
- On-axis frequency response, measured at one metreDone
- Off-axis response at 45, 90 and 120 degreesDone
- Impedance of the complete system with the crossover fittedDone
- Plots and their interpretation published on this same pageDone
External validation1/5
- Measurement protocol writtenDone
- Looking for a company or lab to validate the measurementsIn progress
- Anechoic chamber measurementTo do
- Full directivity set, Spinorama styleTo do
- Blind comparative listening against reference monitorsTo do
06Finishes, packaging and production5 of 13
Turning a prototype into something that can be manufactured, finished and sent to someone’s home without arriving damaged.
Look and finishes2/5
- First visual previews and finish simulationsDone
- Decision on the lacquered variantDone
- Looking for lacquer finishing suppliersIn progress
- Looking for wood veneer suppliersIn progress
- Settling the three final finishesTo do
Packaging and shipping3/5
- Real weights calculated, part by partDone
- Shipment split into four packages per pair, none over 15 kgDone
- First double-wall cardboard supplier consultedDone
- Looking into packaging systems and die-cut protective traysIn progress
- Settling the carrier and shipping ratesIn progress
Kit documentation0/3
- Illustrated assembly manualTo do
- Step-by-step assembly videos, reachable by QR codeTo do
- Cutting plans published openlyTo do
07Presentation and public release4 of 10
The project has been told in the open from day one. What is left is playing it in front of people and opening the first series.
Telling the project4/4
- Public Opus I page on HifiCaféDone
- Series of process videos on the YouTube channelDone
- Opus I community group openedDone
- List of people interested in the listening sessionsDone
First public listening session0/3
- Looking for a room in BarcelonaIn progress
- The Stereo Vintage Barcelona fair, under consideration as the launch venueIn progress
- Date and format confirmedTo do
Opening the first series0/3
- Final price and termsTo do
- Reservations for the first numbered seriesTo do
- First deliveriesTo do
The method
Loudspeaker design stopped depending on mysticism and intuition decades ago. Today there are simulation tools, analysis systems and a large body of literature that let you predict precisely how each decision affects the final result. The Opus I applies that accumulated knowledge.
Development focused on two critical goals:
- Reduce system distortion. Both the non-linearity of the drivers themselves and the acoustic and mechanical colouration the cabinet adds.
- Optimise the angular response. A balanced on-axis frequency response combined with progressive off-axis directivity. The work of Floyd Toole and Sean Olive shows that this correlation is the key factor in listener preference in blind tests.
That does not mean there is one correct sound: certain physical behaviours are statistically preferred because they cause less listening fatigue and stay closer to the original message.
The kit format as a philosophy. Many of the mechanical solutions in the Opus I would be unworkable on an automated assembly line, because of machining cost and curing time. The kit brings back the audio culture of the sixties and seventies: building it is not only cheaper, it is how you get to understand the loudspeaker from the inside. It is also, to date, the first commercial loudspeaker kit designed and manufactured in Spain with Beyma drivers, which are Spanish-made too.
The project is still being fine-tuned. Before the design is closed, the system will be checked with near-field and far-field measurements and with blind comparative listening against reference monitors on the market, keeping the result clear of price or expectation bias.
Construction
Why it is built this way
Every geometric and material decision balances acoustic performance against what can realistically be assembled at home. The design is meant to make the result depend on the project, not on the previous skill of whoever builds it.
See the 9 construction points
40 mm laminated walls
A structure made of 23 CNC-machined board slices. The many glue lines between layers act as structural damping and reduce the energy radiated by the panels.
Vertical compression
Four M8 steel threaded rods run through the body from top to bottom and keep it under constant pressure. They raise mechanical stiffness and guarantee a perfect seal, with no butt joints.
Integrated bass-reflex port
The tuning duct is milled straight into the wooden slices themselves. It avoids the tube resonances of commercial plastic ports and keeps the tuning dimensionally exact.
Professional Beyma drivers
An 8NMFW woofer (carbon cone) and a T25M dome tweeter. Professional-grade components, chosen for their low dynamic compression and thermal stability at high sound pressure.
Flush-mounted baffle
Both drivers sit flush with the baffle in micrometric rebates. This minimises edge diffraction at the front.
Guided assembly, no mistakes
Every wooden part arrives numbered and tongue-and-grooved so it fits in one position only. No special tools and no hand-fitting required.
Jantzen + Dayton crossover
A passive crossover with air-core coils (no core to saturate) and polypropylene capacitors from Jantzen Audio and Dayton Audio. It includes impedance-correction and attenuation networks calculated for a clean transition between ways.
Specific details
A custom rear terminal plate, laser-cut in black acrylic (engraved, with holes for the binding posts), integrated into the elliptical curve of the cabinet.
Foundations
The science behind it
The Opus I is not based on esoterics; it rests on technical literature verified in primary sources (AES, JAES, BBC Research). The core references for the design are:
See the sources
Electroacoustic modelling
- Thiele-Small · Leo Beranek · Harry OlsonSystem parameters and the classic treatises on diffraction
Perception and directivity
- Floyd Toole · Sean Olive · Allan DevantierSpinorama (CTA-2034), directivity and preference prediction models
Non-linear behaviour
- Earl Geddes · Wolfgang KlippelModern distortion analysis
Crossovers and filters
- Siegfried LinkwitzDispersion networks and filters
Simulation and measurement
- VituixCAD · Hornresp · REWDesign optimisation and experimental measurement
The brands mentioned belong to their owners and appear only as a technical reference.
Crossover
The crossover
The crossover is the brain of the loudspeaker: it splits the signal coming from the amplifier between woofer and tweeter, sending each driver only the band it can reproduce and protecting it from the one that would damage it. But it does more than «cut»: it corrects the frequency response, matches the levels of the two drivers, compensates their impedances and aligns their phase so both sound like a single coherent source. That is why a well-designed crossover is the difference between a loudspeaker that measures well and one that also sounds natural. And the maths is not enough without good materials: air-core coils (no core to saturate), low-loss polypropylene capacitors and non-inductive power resistors keep the signal clean, stable at high volume and faithful over time. In the Opus I the crossover is passive, built from Jantzen Audio and Dayton Audio parts, measured piece by piece and mounted on a printed circuit board shaped like the cabinet itself.
See the schematic and the component detail
Functional blocks
Woofer low-pass
L1 · L2 · C1 · C2 · R1The two series coils (L1 1.58 mH and L2 0.8 mH) let the bass through to the 8NMFW and progressively hold back the treble. Capacitors C1 (22 µF) and C2 (4.7 µF) shunt what is left over to ground, and R1 (1.8 Ω) damps that network so the cut is clean and free of resonances.
Impedance compensation (Zobel)
C3 · R2C3 (22 µF) in series with R2 (18 Ω) forms a Zobel network at the woofer input. It corrects the impedance rise caused by voice-coil inductance, so the low-pass filter «sees» a stable, resistive load and works exactly as calculated.
Tweeter high-pass
C4 · L3C4 (8.2 µF) in series with L3 (0.55 mH) to ground forms a 2nd-order high-pass (12 dB/oct). It blocks the bass that would damage the T25M and passes only the top band it can reproduce.
Notch filter
L4 · C5 · C6 · R3L4 (0.7 mH) with C5 (1.5 µF) and C6 (1 µF) forms a series resonant network to ground that «sucks out» a specific peak in the tweeter response. R3 (4.7 Ω) sets the depth and Q of that trap, smoothing the curve without overdoing it.
L-pad attenuator + bypass
R5 · R4 · C7R5 (3.3 Ω) in series and R4 (12 Ω) in parallel form an L-pad: they bring the tweeter level down to match the woofer sensitivity while keeping the impedance seen by the crossover constant. C7 (3.3 µF) bypasses R5 at the top end so the last octave keeps its air and sparkle.
Components
Beyma drivers
Both drivers in the Opus I come from Beyma’s NMF (Near & Mid Field) series: a new high-end range the Valencian manufacturer designed specifically for near and mid field —domestic high fidelity and recording studios. Developed over two years of multiphysics simulation in search of extreme linearity and minimal distortion, Beyma sums it up as «live sound at home».
Why Beyma
Choosing the drivers is the decision that shapes a two-way design most: they are what moves the air. After comparing several brands, the drivers in the Opus I are Beyma, and not for a single reason.
Driver quality
Professional-grade components, not consumer catalogue parts. The NMF series comes out of two years of multiphysics simulation chasing linearity and minimal distortion: an honest base to build a good loudspeaker on.
More than half a century of history
Founded in 1969, Beyma is today one of the reference brands in professional audio in Europe. Behind every driver there are fifty years of accumulated craft.
Reliable and rugged
Born for professional sound —tours, venues, studios— they take far more than you will ever ask of them at home. That ruggedness turns into peace of mind: a loudspeaker for years.
A Spanish company
They design and manufacture in Moncada, Valencia. Working with a local manufacturer shortens distances and lead times, and keeps the project close to home.
Professionalism and decency
In every contact, from engineering to sales, the same seriousness and the same good treatment. It is a pleasure to work with people like that.
But if I have to keep one reason above all the rest, it is the most human one: with Beyma you can talk. You pick up the phone and on the other end there are engineers, designers and a sales and communication team willing to discuss, to explain what you ask and to listen to what you propose. It is not a closed catalogue or a form that never gets answered. We are all people —and in the end, this is made by people for people.
Josep Maria Marimon
Get to know Beyma and its drivers
Beyma was founded in 1969, when the Masip family moved from Barcelona to Valencia to build loudspeakers. It designs and produces at its facilities in Moncada (Valencia). In 1974 it took its products to the Musikmesse fair in Frankfurt, and since 1976 it has exported across Europe; more than fifty years later it is one of the reference brands in professional audio.
The two drivers in the Opus I
Beyma 8NMFW
8″ woofer · low-mid
- Diameter
- 200 mm · 8″
- Impedance
- 8 Ω · minimum 7.4 Ω
- Power
- 200 W AES
- Cone
- Carbon fibre
- Voice coil
- 2″ QUATTRO in/out aluminium
- Xmax
- ±9 mm
- Motor
- Ceramic (FEA) · Malt Cross® cooling
Beyma T25M
Dome tweeter · 1″
- Dome
- 25.4 mm · aluminium-magnesium
- Impedance
- 4 Ω · minimum 3.3 Ω
- Power
- 20 W AES
- Sensitivity
- 88 dB · 2.83 V / 1 m
- Response
- 1.5 – 30 kHz
- Recommended crossover
- 2.5 kHz · 12 dB/oct
- Motor
- Optimised ceramic (FEA)
Measurements
From the test bench to the anechoic chamber
Provisional measurements
The plots below are preliminary: they were taken in an ordinary room —not an anechoic one— using time gating to isolate the direct sound. They are good enough to refine the design, but they are not the final word yet. Final certification will come with anechoic chamber measurements, and this data will be updated then.
A loudspeaker is not «tuned by ear». It is measured, corrected and measured again, dozens of times, until the numbers confirm what you are after. That is what separates real design from opinion, and it is how any project that means to reach the market is done.
See the measurement method and the plots
Why a loudspeaker should be as flat as possible
A loudspeaker is, above all, a translator: it turns an electrical signal into sound. Ideally it invents nothing —it gives back every frequency, from the deepest bass to the finest treble, with the same weight it was recorded with. When we plot its frequency response (sound level against frequency), that fidelity shows up as a line as straight and horizontal as possible.
Every deviation from that line is a lie the loudspeaker adds to the music. A peak makes one area —bright treble, swollen bass— sound louder than it should and take over the rest; in time it tires the ear. A dip does the opposite: it buries information that was in the recording and that we will now never hear. A flat loudspeaker is not a «cold» loudspeaker, it is an honest one: the character should come from the recording, the room and your taste, not from a loudspeaker that colours everything the same way.
And it is not enough for the line to be flat right in front of the loudspeaker: what the sound does as it escapes to the sides and bounces around the room matters too (directivity). Toole and Olive showed that a flat on-axis response combined with directivity that falls off smoothly and progressively is, statistically, what listeners prefer in blind tests. That is the target behind every measurement.
The process, in two stages
Preliminary measurements in a real room
Before spending a single euro on an anechoic chamber, the prototype is measured in an ordinary room. The problem is that walls, floor and ceiling send back echoes that dirty the measurement. The answer is not a perfect room but a rigorous method:
- Calibrated measurement microphone. Every mic comes with its own calibration file, which corrects its small imperfections so what it records is faithful to the real sound rather than to the character of the microphone.
- Calibrated sound card. The audio interface is referenced against itself (calibration loop) so neither capture nor playback leaves its own fingerprint on the measurement.
- A computer with REW and time gating. REW (Room EQ Wizard) applies time gating: the response is cut off just before the first wall reflections arrive, so the measurement «sees» only the direct sound of the loudspeaker. It is a «synthetic» anechoic chamber, valid above a certain frequency.
- Equidistant placement, away from walls. Loudspeaker and microphone are placed high up, centred and as far as possible from any surface. The longer the echoes take to arrive, the longer the clean time window and the lower in frequency you can trust the measurement.
With this setup you enter the real working loop: measure, change one crossover value, measure again. Repeated dozens of times, this is what lets you tune the crossover until the target curve falls into place. The bass, where time gating stops being reliable, is measured separately in the near field and spliced onto the rest.
Certification in an anechoic chamber
An anechoic chamber is a room built so that no echo exists: its walls absorb all the sound and the loudspeaker is measured as if it were floating in open space, with no reflections and no time-window limits. It is the perfect measurement.
But renting one costs thousands of euros per session. So it is not the tool you develop a loudspeaker with, it is the one that certifies it at the end: once the design has been refined with preliminary measurements, the chamber confirms the full response with total precision —including the bass region and the off-axis response— and seals the quality of the result. Taking a half-finished design into the chamber would be throwing money away; taking a polished one is the logical, responsible step.
Prototype plots
Provisional data, measured in-room with time gating · pending validation in an anechoic chamber.
Impedance, for anyone who wants to dig deeper
What impedance is and why we measure it
Impedance is the resistance the loudspeaker offers to the current the amplifier sends it, and it changes with frequency. Measuring it needs no anechoic chamber —an electrical setup with a reference resistor is enough— so, unlike the acoustic curves above, these are already final. And their shape is an honest X-ray of what happens inside the cabinet: where the woofer resonates, what frequency the port is tuned to, and what load the amplifier you connect will see.
Real electrical measurements. The system curve combines the measured woofer with a model of the tweeter, which is still to be measured.
Matching
What to drive it with
It is the question that comes up most often and the one almost no manufacturer answers with numbers. Here they are: the Opus I is an easy loudspeaker to drive, and the measured impedance curve proves it.
Recommended power window
20 W120 W
per channel · amplifier stable into 4 Ω
Any amplifier stable into 4 Ω
The Opus I is rated at 4 Ω nominal, not 8: the 8NMFW woofer is 8 Ω, but the T25M tweeter is 4 Ω and the system minimum with the crossover fitted drops to 3.1 Ω around 8 kHz —a region where music carries very little energy. In the bass, where the amplifier is really asked for current, the load stays around 8 Ω. Any amplifier that claims stability into 4 Ω drives it comfortably, and today that is practically all of them.
A little power goes a long way
With 90 dB sensitivity (1 W at 1 m), about 20 W per channel is enough to comfortably exceed 95 dB peaks at the listening position in a normal living room. Extra power is peace of mind, not a requirement.
Valves suit it well
High sensitivity combined with a load without extremes makes the Opus I a rewarding cabinet for valve amplification. A 20-30 W valve integrated has no trouble with it.
Bi-wiring and bi-amping
The terminal plate comes ready for bi-wiring or bi-amping if you want to explore that. It is not compulsory: with a single pair of cables the loudspeaker works exactly as designed.
Gallery
Work in progress
Real photographs of the build process in the workshop. No studio lighting and no retouching: the road from prototype to production.
FaseIdeation
Video
Videos
The build
What to expect if you choose the kit
Building the Opus I is not a carpentry exam. The design is worked out so the result depends on the project and not on the hands of whoever builds it: parts only fit in their correct position, the crossover arrives assembled and tested, and the steel rods themselves act as clamps while the glue dries.
LevelBeginnerno previous experience in carpentry or electronics needed
Time≈ 2 hthe full pair · drying time on top of that
SolderingNonethe crossover arrives assembled, measured and factory-tested
ClampsNot neededthe four M8 rods compress the whole stack on their own
What arrives at your door
«Lira» cabinet
The slices for both cabinets, numbered and already threaded onto their rods in assembly order.
Drivers
Two 8″ Beyma 8NMFW woofers and two Beyma T25M tweeters, in their factory packaging.
Hardware and crossover
Both crossover boards assembled and tested, the screws, the terminal plates and the sealing material.
The build, step by step
- 01
Glue and stack
The slices come in order, threaded onto the rods. You separate them, apply glue to the mating face and slide them back down the rods. Guided by the four steel axes, they cannot go out of square.
- 02
Tighten the rods
You tighten the nuts on the four M8 rods and the whole stack sits under constant pressure. That compression replaces clamps and guarantees the seal between layers, with no butt joints.
- 03
Fit the crossover inside
The crossover board is cut to the profile of the cabinet itself so it can go in through the woofer cutout, which is the only way inside. You place it and connect it to the rear terminal plate. Nothing to solder.
- 04
Mount the drivers
Woofer and tweeter are screwed into their baffle rebates, which leave them flush with the wood. You connect the spade terminals, watching polarity, and close it up.
- 05
Finish it
The cabinet arrives in bare MDF, ready to paint, lacquer or treat. This part is yours: it is where the kit stops being a product and becomes yours.
What you provide
- Wood glue (PVA)
- A 13 mm spanner or ratchet for the M8 rod nuts
- A screwdriver to fix the drivers
- A damp cloth to wipe off excess glue
- Fine sandpaper, only if you are going to lacquer the cabinet yourself
What the kit does not include
- The cabinet finish: paint, lacquer or varnish are down to you (the assembled version does arrive finished).
- The speaker cable to your amplifier.
- The amplifier. There is a guide below on what to drive it with.
Open source
Materials for the community
We believe in shared knowledge. With the launch of the kit, the cutting plans, the 3D models and the crossover schematic will be released free of charge. The links in grey are not available yet.
CNC cutting plans
Cutting files for the 23 slices and the baffle of the «Lira» cabinet.
- CNC cutting plans (.dxf / .pdf)coming soon
Laser-cut terminal plate
Custom rear terminal plate in laser-cut black acrylic: engraving and holes for the binding posts.
- Laser cutting plan for the terminal plate (.dxf / .svg)coming soon
Crossover schematic
Jantzen Audio passive crossover.
Driver specifications
Official Beyma datasheets for the drivers in the kit.
How to get one
Two ways to own the Opus I
The Opus I comes in two forms, so you can pick the one that suits you: build it yourself and save while getting to know the loudspeaker from the inside, or receive it finished and ready to play.
Coming soon First series reservation
Limited, numbered series
Reservations for the first Opus I series open soon: numbered, hand-signed units, paid in instalments and refundable until dispatch. Leave us your contact details and we will let you know as soon as it opens.
Option 1 · Kit
As a kit, to build at home
You get the Opus I in three boxes and assemble it yourself, guided step by step.
- Three boxes: the wood for the «Lira» cabinet, the Beyma drivers and the crossover, already assembled and tested.
- Illustrated instructions and a QR code with step-by-step assembly videos.
- About two hours of work per pair of cabinets, much like flat-pack furniture: parts arrive numbered and tongue-and-grooved, and only fit in their correct position.
- The cabinet arrives ready to paint or treat: you give it the finish yourself, at home, the way you like it.
- The cheapest route, and the one that lets you understand the loudspeaker from the inside.
Option 2 · Assembled
Assembled and finished
You receive the cabinets finished in the workshop, ready to place and connect.
- Cabinets fully assembled and adjusted in the workshop, to the standard you would expect from a traditional dealer.
- A choice of three different finishes.
- Nothing to build: they arrive ready to put in place and enjoy.
Finishes for the assembled version
Simulations · not real samples
These images are simulations, not real samples. The final finishes are still to be decided.
Or buy the modules separately
If you already own part of the system or prefer to spread the cost, it is also available module by module. The drivers are offered at retail price; the saving is in building the cabinet yourself, avoiding manufacturing, packaging and shipping costs.
Opus I wood kit23 slices + CNC-machined baffle, ready to glue.Coming soon
Driver kitA matched pair of Beyma 8NMFW + T25M, at a special price for the community.Coming soon
Advanced passive crossoverJantzen Audio components. Choose a solder-it-yourself kit or a finished board.Coming soon
Questions
Frequently asked questions
The project is still a prototype. What does that mean?
That the design is final —the «Lira» cabinet, the Beyma drivers and the Jantzen crossover you see in the specs are the ones being manufactured— but the product is still in its last stage of refinement: the finish is being settled and the anechoic chamber measurements are still to come. You can follow the real state of the project on the timeline at the top of this page, which is updated as things move.
Are the finishes in the photos the final ones?
No. The finish images are simulations, not real samples, and the final finishes are still to be decided. The finish depends on how you buy the Opus I:
- Self-assembly kit: it arrives in unpainted MDF, so you can finish it at home the way you like.
- Assembled version: you choose from several finishes, which we confirm with you before building your unit.
What if I build it wrong?
That is the reasonable worry of anyone considering a kit, and the design is built around it: the slices are numbered, threaded onto their rods and tongue-and-grooved, so they only fit one way. The crossover arrives assembled and tested, so there is nothing to solder and nothing to calculate. While the glue has not set you can still correct the position of a slice. And if you get stuck, you write straight to the designer: there is no customer service department in between.
Do I need to be a carpenter or know electronics?
No. The build takes about two hours for the full pair and needs no soldering, no clamps and no special tools: the four steel rods do the clamping while the glue dries. The «The build» section on this page has the detail on level, time, tools and what is in each box.
Where is it designed and manufactured?
The Opus I is designed in Barcelona and the drivers are from Beyma, who design and manufacture in Moncada (Valencia). The CNC machining of the cabinet and the lacquering are also done in workshops around Barcelona. To date it is the first commercial loudspeaker kit designed and manufactured in Spain with Beyma drivers.
Does it come with a warranty?
Yes, the 3-year legal warranty. And since it is hand-made by its author, anything that comes up is dealt with directly, with no middlemen.
Public presentation
Autumn 2026
If you want to hear about the first listening sessions or the details of the limited series pre-order, leave me your contact details.
Community
Questions and answers
The channel is open to discuss simulations, suggest changes or sort out technical questions directly with the designer.
Join the Opus I community
Come into the project group to follow the build, share your own progress and sort out technical questions directly with the designer.
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