Archive for the ‘Active’ Category

Jupiter 6103s



Juglans nigra, more commonly known as Eastern Black Walnut or simply Walnut, has long been one of the most sought after cabinetry hardwoods in North America. Taking its name from the Roman god of the sky, Jupiter, (Juglans being a compounding of the Latin for Jupiter’s Acorn), its remarkable strength, striking color, and fine workability have made it a favorite among woodworkers the world over for centuries, truly a wood worthy of its godly namesake.

Walnut was the clear choice for this design as it immediately evokes the feeling of a classic 70s hi-fi stereo. The rich brown of the walls and the black front baffle were a near uniformity of hi-fi speakers of the era. And the sound too aims to capture some of the feeling often associated with that era of music: warm, laid-back, and pleasant. However, the retro-styled exterior belies a very modern internal system.

A fully digital crossover networks allows for the fine tuning of the entire system to suit the needs of any particular room. The 3-way functionality also allows each driver to function within its most efficient frequency range. The height is calculated to center the mid and tweeter with an average listener’s ear when seated on an average couch (roughly 40″ from the ground).

With their end use being “do-anything” living room stereo towers, these speakers need to be able to cope with a wide array of content, from background music to intensive “home” mix review, from television to intense cinema. Versatility is key to their very existence.

Key Points

  • Balanced, broad frequency response 30 Hz – 30 kHz
  • Clarity through entire frequency band
  • Warm, flattering  music playback
  • Classic visual aesthetic
  • Fountek NeoCD 3.5H – Horn Loaded Ribbon Tweeters
  • SB Acoustics SB17CAC35 – Ceramic 6″ Mid-Woofers
  • Dayton Audio RSS265HF – Aluminum 10″ Subwoofers
  • 3-Way digital crossover (miniDSP 2×8)
  • +/- 1.5dB 30Hz – 30 kHz
  • f3 of 28Hz
  • f10 of 21Hz
  • Hand-rubbed oil finished Eastern Black Walnut Cabinet
  • Double-walled front baffle for added rigidity
  • Fully sealed enclosure for increased transient definition
  • Warm, flattering frequency response

Selected Measurements

Overall Frequency Response (60 dB range)


Integrated Frequency Response (20 dB range)


Overall Harmonic Distortion


Integrated Step Response


Overall Waterfall Plot (18 dB Range)


Photo Gallery

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Jupiter 6103 Glossy





Prunus serotina, or black cherry, is a hardwood species found throughout the Upper Peninsula of Michigan. It is known not only for burning all night in the wood stove, but also for it’s gorgeous color, figure, and grain pattern when properly finished. It was for this reason that Black Cherry was chosen to comprise the the baffles of these loudspeakers, eventually leading to the name Serotina.

From the beginning the intention was for these loudspeakers to provide the most pure, uncolored reproduction of any audio signal that was passed through the system. This meant a very broad spectral response and extremely accurate transient reproduction were necessary of the final product, and were achieved by employing multiple high-quality drivers and sizable, sealed enclosures.

An active crossover network ensures that the system can be fine-tuned for a wide variety of applications. At 6′-4″ they are stretched to accommodate the height of the end user when at a standing desk. However, with a quick re-alignment of the drivers using delay presets, the same great results can be enjoyed from a seated position for an extended stereo listening session or home theater application.

Key Points

  • Uniform Frequency Response
  • Highly Versatile
  • Clean System Integration
  • Pleasing, Natural Aesthetics
  • Raven Point Source Tweeter
  • 5″ Eton 5-212/C8/25 HEX Woofer
  • 10″ Focal P25FS Subwoofer
  • 3.5 Way Active Crossover Network [MiniDSP]
  • +/- 1.5dB From 40Hz to 22kHz
  • 3dB down @31Hz
  • 10dB down @25Hz
  • Oiled Black Cherry baffles
  • Tall for use at a standing desk
  • Sealed cabinets provide accurate transient response
  • A narrow front baffle makes for wide horizontal dispersion
  • Removable back panel for future access

Selected Measurements

Integrated Frequency Responseserotina integrated
Horizontal Off-Axis Response serotina horizontal

Blue = 60deg | Lime = 45deg | Red = 30deg [listening axis] | Purple = 15deg

Serotina with designer


The HNY: Buns

Designed and Built By Sam Palumbo

Design goals

  • Home Entertainment and Mixing Use
  • Floor Standing
  • Natural Wood Look
  • No taller than 3ft 7in


  • Fully Active 3-way Speaker
  • Founteck NeoX1.0 Ribbon Tweeter
  • 5-in Dayton Audio RS125-4 Mid Woofer
  • 8-in Dayton Audio RS125-4 Reference Woofer 
  • Dimensions: 10”, 13”, 43”


  • F3 of 40 Hz
  • +/- 2dB from 40Hz- 22kHz


May 2, 2019 Leave a comment

Design Goals:
  • Casual listening
  • MTM design for subtle bass extension
  • Small size for portability
  • Budget of $900 dollars
Key Features:
  • 8″ x 12″ x 18.5″
  • f3 = 34.87Hz
  • Vb = 0.6256 ft cu
  • +/- 2.5dB 60Hz – 20kHz
  • 2″ Ports
  • Active 2 – way
Driver Selection:
  • Woofers: SB Acoustics – 5” SB15NBAC30-8
  • Tweeter: Peerless Vifa XT25BG60 – 04


April 27, 2018 Leave a comment


The TNS6 or “Temporarily Named Speaker 6” is a 2 way loudspeaker.

Design Goals:

  • Relatively small size suitable for resting on a desk with maintaining maximum desk space.
  • Crisp transients while reaching an f3 of at least 60Hz
  • Natural wood aesthetic

Technical Specifications:

  • Tweeter: Dayton Audio ND20FB-4
  • Woofer: Dayton Audio RS225-8
  • +/- 2db 49Hz-20kHz
  • f3 of 47Hz
  • Dimensions 11.25″ x 10.25″ x 19.75″Frequency2.PNG


Speaker Glossy

MC8R Studio Reference Monitors


IMG_0469Designed by Michael Chopp

Design Goals:

  • Portable music mixing monitors for professional use
  • Flat frequency response full range
  • $1000 budget
  • Natural wood look – visually appealing

Key Specifications:

  • Drivers
    • Fountek Neo X 2.0 Ribbon Tweeter
    • Fountek 8″ FW200 Midwoofer
  • F3 of 40Hz – Vented Enclosure
    • 2″ port on front baffle
  • +/- 1.5dB from 50Hz – 20kHz
  • 0.1% THD from 50Hz – 20kHz
  • Dimensions: 13″ x 22″ x 17″ (w, h, d)
  • MiniDSP active crossover
    • Tweeter at 1.8kHz
    • Woofer at 2.2kHz
  • Baltic birch exterior, MDF interior

Frequency Response:

Screen Shot 2018-04-26 at 12.11.46 PM

Integrated Frequency Response:

Screen Shot 2018-04-26 at 12.11.31 PM

Off Axis Response:

Screen Shot 2018-04-26 at 12.20.03 PM

Harmonic Distortion:

Screen Shot 2018-04-26 at 12.19.47 PM

MC8R Design Binder

MC8R Speaker Glossy



AH-8 “Revealers” Studio Monitors

Speakers 2

Design Goals:

  • Flat frequency range
  • Excellent clarity and depth
  • Studio monitors
  • $1500 Budget

Key Features:

  • F3 of 45 Hz
  • +/- 1 dB 45 Hz to 20 kHz
  • Sealed Box
  • Active Crossover via MiniDSP 2×4 DSP
  • Off center driver position
  • Custom built and amp rack

Driver Selection

  • ScanSpeak Classic 21W/8555-10, 8″ Woofer
  • ScanSpeak Illuminator R3004/6620-00 1″ Tweeter

new integrated right


Harmonic Distortion

Impulse Response

allen harrison 4740 research document

Speaker Glossy

AH-8 Speaker Drafting 4-2-18