adhoc Flow/1
Compact Form.
Expansive Sound.
Flow/1 is a compact 3D-printed loudspeaker based on a folded coaxial tapered quarter-wave tube. It is a DIY project for makers who want a bespoke audiophile loudspeaker. Flow/1 folds a 4.8L air mass through unequal-length segments of concentric rings inside a compact enclosure. Its patented acoustic geometry works with the 180-degree swivel tweeter and active FIR crossover to produce useful bass extension without booming, precise imaging, and balanced sound from a loudspeaker small enough to fit easily in a real room.
Designed Around The Air Flow
Compact, Tuned Enclosure
The enclosure does the work. Printed internal geometry controls the rear wave, spreads pipe modes, and lets a small loudspeaker reach lower without turning bass into boom.
Coaxial Point Source
Flow/1 packs a 180-degree swivel tweeter and an optimized quarter-wave path into a compact 5-liter enclosure. Flow/1 balances bass extension and placement versatility in a format meant to reduce the usual seating and placement limits of small speakers, with every cubic centimeter performing a dedicated acoustic function.
Swappable Driver Modules
Flow/1 is designed around removable high/low driver modules. A complete driver pair can be swapped between enclosures in under a minute, making driver comparison, measurement, repair, and future upgrades practical. Current modules support SB Audience, AuraSound, Wavecor, Tang Band, and Dayton Audio drivers, with more to come.
Large Sound From A Small Speaker
The Flow/1 produces a frequency response that is larger than its size should allow, reaching down to 30Hz, typically found in larger speakers.
Designed for the Print-Build-Do-It-Yourself Maker
Flow/1 is a natural project for the PBDIY community: makers who print, build, repair, and create things themselves, supported by shared knowledge rather than finished commercial products. It is an engineered loudspeaker system you build, configure, measure, and bring to life by hand.
- It is for makers who want a bespoke loudspeaker, not another off-the-shelf box.
- It is for listeners who want audiophile performance, satisfying bass, and stable imaging from a compact, versatile package that fits in a real room.
What You Get
Maker’s Guide
This is the main build guide for Flow/1. It covers the materials, fit, tolerances, assembly steps, and construction details needed to turn the printed parts into a working loudspeaker. It explains the design intent behind the steps, so you can build with confidence. Click the image below to view or download the Flow /1 Maker’s Guide and see what it takes to build a pair of Flow/1 loudspeakers. Available to everyone.
Stand Assembly Guide
Flow/1 will sit comfortably on a shelf standing vertically or lying horizontally. You can make stands to expand placement options for the Flow/1 speakers. This guide tells you how to print stands or make hybrid stands with printed and wooden parts. Click the image below to view or download the Stand Assembly Guide and see what it takes to build a pair of Flow/1 stands. Available to everyone.
Design Files
Complete STL and STEP files for all enclosure components, optimized for printability, fit, and acoustic performance. Available to subscribers.
Click the image of the models to access the design resources, or to subscribe for access if you are not already an adhoc member.
Image Gallery
Click on the image above to view the Image Gallery
Created from First Principles
Flow/1 started with the acoustic problem: move a 4.8L air mass through a 1.7-meter path, suppress tube modes, preserve imaging, and keep the loudspeaker small enough for a real room. The folded coaxial quarter-wave geometry described in U.S. Patent 7,925,036 B2 is the core. Driver layout, FIR crossover, modular construction, 3D printing, and a swivel high-frequency driver all serve that geometry.
Every dimension, every taper and fold, every cleft, dimple, and pimple, and every internal cubic millimeter has a purpose.
Flow/1 Explosion
Why Bother Building This Flow/1 Speaker?
Flow/1 is a compact loudspeaker system, with the flow of air shaped and controlled down to the cubic millimeter. It is built to disappear as a source and leave behind the music: full-range, balanced, satisfying, and free of the exaggerations that can make many small speakers impressive at first and tiring over time.
Most speakers in this size class force a tradeoff between depth and detail. By giving every cubic centimeter a working acoustic role, Flow/1 reduces those compromises. Its 4.8L enclosure and 180-degree swivel tweeter balance low-end authority with the placement flexibility needed in real listening spaces.
Flow/1 challenges those tradeoffs through careful geometry, controlled loading, time alignment, and DSP, rather than brute size. The goal is simple: deeper bass from a smaller footprint, sharper image focus, and a more stable presentation from a speaker that still suits a real room.
Because building it gives you access to the whole system:
- the acoustic design
- the physical design
- the DSP
- the reasoning behind the choices
This is serious DIY project, built around a compact active loudspeaker for serious listening, with controlled low-frequency extension, point-source behavior, precise imaging, and a form factor that fits in everyday spaces. For people drawn to PIY, DIY, or BIY, the effort is part of the reward. You end up with a finished loudspeaker and a working knowledge of the machine behind it, including the choices you made and the differences you can hear.
The cost of building one is an exchange of money, time, care, attention, and effort. In return, you get something personal, unusual, and deeply considered, something that reflects your standards rather than a manufacturer’s brief.
So the real answer is this:
- You bother if you want a loudspeaker that disappears into the room
- You bother if you want to build something rare.
- You bother if you want to understand what you are hearing.
If that describes you, Flow/1 is exactly the kind of project worth building.
Press ‘Subscribe For Access’ to the Flow/1 3D files, future design updates, and the member forum.