Thunder and Lightning


cp-transducer-2019-1424

Designed and built by Chris Wilson

Gonçalo alves is a Brazilian hardwood. It is sometimes referred to as tigerwood — a name that underscores the wood’s often dramatic, contrasting color scheme, that some compare to rosewood. It is considered one of the most beautiful of tropical woods, has a tough reputation, too. Strong and durable, it’s used for construction in its homeland and secondarily for fine furniture.

I wanted my speakers to be different. So I built a Lichtenberg machine and burnt Lichtenberg figures into the front side of my baffle. Finished by filling with blue glow-in-the-dark resin, I think I fulfilled my goal.

Since I invested so much time into the outward appearance, sound quality would have to be top notch. That is why I bought ribbon tweeters and ceramic woofers for the desktop monitors. The combination of those two provided the widest possible range (55Hz-22kHz) while having the flattest response. The subwoofer had to go as low as possible while still being inconspicuous and out of the way. The final design follows closely the form-factor of the footrest that is beneath my desk and is painted black. With its 10″ subwoofer and sealed cabinet design, it can get as low as 28Hz.

Design Goals

  • Visually appealing in a unique way
  • Flat response
  • Full range
  • Relatively Portable

Key Features

  • Unique lightning bolt effect
  • Beautiful wood grain with hand-rubbed oil finish
  • Sealed enclosures for increased transient response
  • Flat tuning

cp-transducer-2019-1415

Specifications

  • Measured F3 of 28Hz
  • +/- .7dB from 100Hz – 22kHz
  • Sealed box including sub
  • Fountek Neo X 1.0 ribbon Tweeter
  • 6″ SB Acoustics SB17CAC35-8 ceramic woofer
  • 10″ Dayton Audio RSS265HF-8 subwoofer
  • Desktop monitors 8.5” x 11” x 14”
  • Subwoofer 15”H x 15”D x 20”W with integrated legs

Overall Frequency Response

Overall PerformanceThe subwoofer and desktop monitor were placed on a tall stand to simulate anechoic conditions. Because of this, the subwoofer is not receiving the 3-6dB boost from the boundary effect from the floor.

Horizontal Off-Axis Response – 0º, 15º, 30º, & 60º off axis

Horizontal Off-Axis ResponseThis measurement was taken closer to the floor. The flat frequency response is being affected by floor reflections. The main data points to look at are above 5kHz.

Overall Waterfall Plot

Waterfall Plot - Full

Impulse Response

Impulse Response

Photo Gallery

This slideshow requires JavaScript.

Advertisements

Jupiter 6103s


20190407_transducer_006


Introduction

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

Goals
  • Balanced, broad frequency response 30 Hz – 30 kHz
  • Clarity through entire frequency band
  • Warm, flattering  music playback
  • Classic visual aesthetic
Drivers
  • Fountek NeoCD 3.5H – Horn Loaded Ribbon Tweeters
  • SB Acoustics SB17CAC35 – Ceramic 6″ Mid-Woofers
  • Dayton Audio RSS265HF – Aluminum 10″ Subwoofers
Specifications
  • 3-Way digital crossover (miniDSP 2×8)
  • +/- 1.5dB 30Hz – 30 kHz
  • f3 of 28Hz
  • f10 of 21Hz
Features
  • 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)

OverallFreqResponse

Integrated Frequency Response (20 dB range)

IntegratedFreqResponse

Overall Harmonic Distortion

OverallHarmDistortion.png

Integrated Step Response

IntegratedStepResponse

Overall Waterfall Plot (18 dB Range)

OverallWaterfallFull


Photo Gallery

This slideshow requires JavaScript.

Jupiter 6103 Glossy

 

Kitten Koffins


Near-field Reference Monitors

Designed by Sarah Calvert

The Kitten Koffins are near-field reference monitors that incorporate a unique shape size that produces a wide dispersion of sound. The coffin cabinet is an excellent shape for producing a flat and even frequency response. Both of which were very important goals of my design.

Due to being a sealed speaker and their smaller shape, the Kitten Koffins have an F3 of about 70hz. They are 13 inches in height and just over 14 inches in depth. Because of the angled shape on the front of the speaker, the width is roughly 10.5 inches. I designed them smaller and to incorporate a subwoofer with the system.

Unrealized 3D Model

Categories: Uncategorized

Serotina


Serotina

Introduction

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

Goals
  • Uniform Frequency Response
  • Highly Versatile
  • Clean System Integration
  • Pleasing, Natural Aesthetics
Drivers
  • Raven Point Source Tweeter
  • 5″ Eton 5-212/C8/25 HEX Woofer
  • 10″ Focal P25FS Subwoofer
Specifications
  • 3.5 Way Active Crossover Network [MiniDSP]
  • +/- 1.5dB From 40Hz to 22kHz
  • 3dB down @31Hz
  • 10dB down @25Hz
Features
  • 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

Serotina_Glossy

HR Designs: The Saadia Rahman Prototypes


The Saadia Rahman Prototypes, by HR Designs
(Photo by Christopher Plummer | 1 May 2019)

The Saadia Rahman Prototypes are the first speakers designed and built by Haroon Chaudhry, Spring 2019. They are designed and built for Saadia Rahman to use in her house for casual listening.

Design Goals:

  • High enjoyment listening in a casual living room setting
  • Exceptional visual aesthetics
  • Easy to setup and use

Features:

  • 100% passive 3-way crossover
  • Padauk front, sides, and back
  • Walnut top, bottom, and wings
  • Easy-to-use terminals

Specifications:

  • Vented enclosure with bass boost from 50-100 Hz
  • Woofer: Dayton Audio DC200-8
  • Midrange: Dayton Audio RS125
  • Tweeter: SB Acoustics SB19ST-C000
  • Total Cost: ~$800 USD

Performance:

Integrated Frequency Response (10 Hz – 50 kHz | 40 dB range)
Horizontal Off-Axis Response (10 Hz – 50 kHz | 40 dB range)

Crossover Design:

  • Woofer: 35 Hz – 300 Hz
  • Midrange: 300 Hz – 3 kHz
  • Tweeter: 3 kHz – 30 kHz
Crossover Circuit Schematic

Documentation:

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

Specifications

  • 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”

Features

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

HSD5


Designed & Built by Henry Sendek
  • Design Goals:
    • Full-Range Loudspeakers for Living Room Entertainment
    • Relatively Portable
    • Extended Bass
  • Specifications:
    • Dual 5″ SB Acoustics SB15CAC30 Woofers
    • Single 5″ Ribbon Fountek CD2.0 Tweeter
    • 2.5Way Active & Passive Crossovers
  • Features:
    • F3 of 45Hz
    • +2dB/-3dB (45Hz to 20kHz)
    • 94dB (Max Continuous SPL)
Full Loudspeaker (Red) | Tweeter (Blue) | Top Woofer (Yellow) | Bottom Woofer (Purple)