Project Bacchus – Tim DeYoung

Introduction

Have you ever been in wonder of what music is? The fact that we as a species can convey story and emotion through a combination of simple tones and rhythms. For when you get down to it, that is exactly what music is, emotion. Sadly though, this is the one main thing missing in most speaker systems, the ability to convey emotion. A speaker that has a flat frequency response or a short impulse is fine and dandy, but when they can’t convey the emotion of the music you are listening to, they are down right useless.

That is why I designed “Project Bacchus”, I have always had an extreme connection with the music around me, and to not only own but to create with my hands a speaker system that enables me to connect with music on an emotional level, that is one of life’s necessities, because what is the point of being in a world full of music when you can’t connect with it?

Design Basics

For the design of “Project Bacchus” I took a lot of inspiration from speaker designers such as Richard Vandersteen and Jim Thiel who preach the gospel of time and phase coherence. Which is when you arrange the acoustical centers of your drivers in the vertical space so that they align in not only time but also phase, which is very difficult to do but when done correctly can be very rewarding.

Design Choices

One of the best ways to give speakers life, is to make sure that they produce a large sound stage. I went about trying to open the stage by doing three things:

1.) 3-Way

I chose to produce a three way system so that all of the frequencies in the spectrum are recreated without struggle. Too many times I see two way systems with large woofers. In order to use a tweeter effectively, it has to cross over around a minimum of 1kHz, so that means the woofer is also producing up to 1kHz, and depending on the crossover order sometimes even three to four octaves above that, which means up to 8kHz! and a woofer any bigger than 2″ can not accurately produce that high of a frequency.

To alleviate this I used three drivers, each of which only producing frequencies which it is comfortable and effective at. This means a 10″ subwoofer which gets crossed over at 200Hz, a 5.5″ woofer which gets crossed over at 2kHz, and a tweeter which is also crossed over at 2kHz.

2.) Stereo Subwoofers

Another design choice I made to try and help widen the sound stage a bit was to have a dedicated subwoofer on both the left and right channel. Because even though low frequencies are mostly omni-directional, the human ears can still distinguish between sources, and having both sources there really helps widen and smooth out the stereo field.

3.) Minimal Baffles

With project Bacchus, I really wanted to open up the sound stage to maximize the listening experience. To do this I committed to having the smallest baffle sizes possible, this will eliminate one of the main reasons why some speakers tend to sound constrained from left to right. To minimize the baffle size, I mounted the tweeter without a box, and I mounted the midrange in a tube which is only a total of half an inch larger in diameter than the driver it houses.

Subwoofer Design

The things which I really enjoy in a subwoofer are tightness and accuracy. Every time I have been really impressed with a subwoofer it has had those two characteristics, the support of the lowest octave isn’t that high on my priority list. To achieve this, I ended up putting my subwoofer in a sealed box, this gave the benefits of transient accuracy, and tightness which I really appreciate in a low end driver.

Woofer Design Choices

Boxes are boring, there are too many boxes out there in the world, and there are too many boxes in my design portfolio. So I decided to go with something I have never even wrapped my head around until this year, and that is a transmission line. For this concept I’ve taken a lot of inspiration from B&W speakers, where their enclousure behind their drivers gradually tappers down to nothing. The thought process behind this is to take all of the energy radiating of the rear of the driver and take it as far away as you can, the hope being that it never returns to the driver to cause distortion and cancelation.

Since I don’t have plastic injection molding machines and my ready (hopefully someday right next to my CNC routing table), I had to improvise. After many hours at the hardware store looking over my options, I picked one, a furnace vent. This vent allows me to get an approximately two foot long tube filled with sound absorption material behind my woofer, which very effectively takes the sound and has it never return.

As a side note: I don’t know if it is me trying to hear it or if it is actually there, but I think that I can hear the tube, but it isn’t on all songs which is weird.

Tweeter Design

I knew from the beginning that I wanted to use a ribbon tweeter, I have never heard a system which utilized them which I haven’t enjoyed. I also knew that to maximize the horizontal dispersion and high-end sparkle which ribbon tweeters are known for, I wanted to minimize the size of the baffle.

End Notes

I REALLY like my speakers, but they are not for everyone. In fact, I think I might have tailored them too much to my specific wants. I very much like mellow sound, even when I mix I try to get a super mellow sounding mix. So I wanted to make listening speakers that suited my tastes, and I really succeeded. When I put on a well recorded jazz ballad, these things sing, and I can feel myself being sucked into the music. But when I put on a pop/punk song on (I don’t know when I would, but we will speak in hypotheticals),  my speakers really tend to suck the energy out of the song, which could be very bad for a lot of people.

One of the aspects of my speakers which I like the best, is how far they sit back in the room. They sound like they are coming from almost ten feet behind where they are standing, which really helps them to blend in to the room, which is one of the key aspects of good listening speakers.

They are also very smooth, it is not the stereotypical “accurate” sound (like dead studio mixing speakers), but instead they just sound like everything flows together, I feel like my speakers really blend voices well within the mix.

Files

Design Statement

Design Proposal_Tim DeYoung

Enclousure Drafting

Drafting Plans_Tim DeYoung

Crossover Schematic

Crossover Schematic_Tim DeYoung

Final Testing Report

Testing Report_Tim DeYoung

Testing Results

Frequency Response

Reverse Polarity

Horizontal off Axis

Left/Right Difference

Step Response

Impulse Response

Waterfall

Minimum Phase

Harmonic Distortion @ 96dB SPL

Crossover Response

Tweeter Measurements

Frequency Response

Horizontal Response

Vertical Response

Step Response

Impulse Response

Phase

Midrange Measuremets

Frequency Response

Horizontal Response

Vertical Response

Step Response

Impulse Response

Phase

Subwoofer Measurements

Frequency Response

Horizontal Response

Vertical Response

Step Response

Impulse Response

Phase

If you have any questions, feel free to e-mail me: tsdeyoun@mtu.edu

Sonic Bluhm 2-Way Loudspeaker System

Overview.

• Designed and built for use as left / right pair for home theater system.
• Primary use, movie and music playback

Features.

• Vented box construction, providing lower f3 frequency
• Unique shape to avoid following problems:
• Panel Vibrations
• Internal cabinet standing waves
• Edge diffraction
• 2.1 cubic foot internal box volume
• Capable SPL, of 90 dB Continuous, 102 peak

Cabinet Construction.

• Cabinet made using constrained layer construction
• There are 4 layers to my cabinet (listed from outside to inside)
• 1) 3/4″ 13 Ply Baltic Birch
• 2) 1/2″ MDF
• 3) 1/8″ Mass loaded vinyl
• 4) 1/8″ Masonite
• Rounded top edge
• Only 3 visible screws per speaker, giving them a very clean and polished look

Drivers.

• Woofer: Seas Excel 8″ W22EX001
• Tweeter: ScanSpeak Illuminator D3004, 1″ soft dome

Documentation.

• Speaker Design Proposal
• Drafting Plans
• Speaker Glossy
• Cross Over Schematic

Testing Results.

System Frequency Response: Purple- Port, Blue- Woofer, Green-Tweeter, Red- Summation

Frequency Response, Tweeter Polarity Flipped

Horizontal Off Axis Testing: Green 0*, Purple 15*, Red 30*, Blue 45*, Yellow 60*

Vertical Off Axis Testing: Green 0*, Red 15*, Blue 30*, Purple 45*, Yellow 60*

Step Response

Impulse Responce

System Minimum Phase Response

Woofer Impedance: Yellow- 8 Ohm resistor, Red- Speaker System

Sonic Bluhm 2-Way Loudspeaker System by Dan Bluhm is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

Rocky Mountain 2-Way

The Life That I Have Been Waiting For

Rocky Mountain 2-Way Loudspeaker System

 Overview:

The Rocky Mountain 2-Way Loudspeaker System was designed to be used as mixing monitors.

Features:

Flat Frequency Response (1.5dB variation)

Sealed Box Construction Providing Accurate Low Frequency Reproduction

Low Frequency Extension: F3= 55Hz, F6= 45Hz, F10= 40Hz

Active Crossover With Computer Controlled DSP that allows for the maximum control of the speaker system

Absorbent Foam Baffle that combats MF Diffraction and Makes the HF more directional.

Capable of 90-98dB Continuous, 110-115 Peak

1 1/4” Cabinet Construction (13ply Baltic Birch/MDF Composite)

2 1/4 Cubic Foot Volume

Custom Made Grill

Made Proudly In Michigan

Drivers

Woofer: Seas Prestige 10″ H1411

Tweeter: Seas Prestige 27TDFC, 1″ Silk Dome Tweeter

Enclosure

Exterior: 3/4″ 13-ply Baltic Birch

Interior: 1/2″ MDF

Documents:

Design Proposal

Drafting Plans

Glossy

Final Testing Report

Block Diagram:

Block Diagram

Testing Results:

Speaker 2 All Drivers

Speaker 1 All Drivers

Speakers 1 and 2 Differences Pt.1

Speakers 1 and 2 Difference Pt 2

Speaker 1 Polarity Flipped Tweeter

Horizontal Off Axis (Black 0*, Green 30*, Red *45, Blue *60, Red *90)

Vertical Axis Frequency Response (Black 0*,Blue *30, Orange 45*, Green 60*, Blue *90)

Tweeter Horizontal Off-Axis Purple=0*, Orange=30*,Red=45*,Green=60*)

Woofer Horizontal Off-Axis (Blue=0*, Orange=30*, Green=45*, Red=60*)

Tweeter Vertical Axis (Purple=0*, Green=45*)

Woofer Vertical Axis (Blue=0*, Red=45*)

Full System Speaker 2 Step Response

Full System Speaker 2 Impulse Response

Tweeter Step Response

Woofer Step Response

Full System Minimum Phase Response

Woofer Impedance Compared with 8Ohm Resistor

Tweeter Impedance Compared With 6Ohm Resistor

Cross-Over Response

Rocky Mountain 2-Way Loudspeaker System by Kenneth G. Stahl III is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.
Based on a work at kennystahlrock.com.

K-Series

Overview

This two-way system allows for high quality, high fidelity playback at a considerably low price. With a frequency response that remains within +/- 3 dB, it meets industry standards for applications such as mixing and mastering. The vented enclosure allows extended bass response. With a passive 3rd order crossover at 1.8 kHz, the summation between the 6 1/2″ woofer and 1″ tweeter maintain a flat frequency response.

System Designer: 

Spencer Karlovits

Features

• Two-way System
• Vented Enclosure
• Passive Crossover
• Under $500

Drivers

Woofer: Seas Prestige 6 1/2″ CA18RLY

Tweeter: Seas Prestige 1″ 27TDFC

Enclosure

• Interior: 3/4″ 11-ply Birch
• Exterior: 3/4″ MDF

Documents

Initial Design Statement

Crossover Schematic

Enclosure Draft 

Final Tuning Report

Testing

System Frequency Response with Crossover Summation

System Response w/ Tweeter Reverse Polarity

System Horizontal Off-Axis Response

Purple 0, Red 15, Green 30, Blue 45, Yellow, 60

System Vertical Off-Axis Response

Purple 0, Red 15, Green, 30, Blue 45, Yellow 60

Woofer Horizontal Off-Axis Response

Blue 0, Yellow 15, Purple 30, Red 45, Green 60,

Woofer Vertical Off-Axis Response

Blue 15, Yellow 30, Purple 45, Red 60

Tweeter Horizontal Off-Axis Response

Yellow 0, Purple 15, Red 30, Green 45, Blue 60

Tweeter Vertical Off-Axis Response

Yellow 15, Purple 30, Red 45, Green 60

Impulse Response

Step Response

System Harmonic Distortion

Woofer Harmonic Distortion

Tweeter Harmonic Distortion

System Phase Response

Woofer Phase Response

Tweeter Phase Response

 

 System Crossover Response

System Impedance Against 8 Ohm Resistor

 

 Left/ Right Speaker Difference

Anechoic Chamber Test Results

System Frequency Response

System Impulse Response

System Step Response

System Waterfall Plot

El Palmisté

Overview

The two-way pair of loudspeakers are designed to function as film and music mixing monitors.  The design includes an 8″ woofer and a 1″ tweeter mounted against a waveguide to improve its potential.  The speakers are vented with a port on each inner side, and have a passive crossover.

  

Design Goals

• Produce 103 spl to meet film mixing standards (83dB SPL with 20 db of headroom).
• Flat frequency response and maintain detailed sound.
• Good low frequency extension.
• Cost around $500.
• Be somewhat easy to move.

Key Features

• 2-way system
• passive crossover
• vented system
• dome tweeter mounted to waveguide
• f3 of 40hz
• bandwidth of +/- 2.5 dB  from 40hz-19khz

Drivers

Scan-Speak Discovery 22W 8″ Woofer

SEAS Prestige 27TDFC 1″ Textile Dome Tweeter

Cabinet

Each wall consists of:

3/4″ ply, 1/8″ loaded vinyl, 3/4″ MDF

Documents

Speaker Drafting

Crossover Schematic

Design Statement

Speaker Glossy

Final Test Report

Tests

Frequency Response With Woofer/Tweeter Summation

Horizontal Off Axis Response (15,30,45,60)
Vertical Off Axis (15,30,45,60)

Frequency Response with Inverted Phase

Step Response

Impulse Response

Impedance as compared to an 8 ohm resister with port and total response

Harmonic Distortion

Phase

Frequency Response Difference Between Speakers

Waterfall Plot in an Anechoic Chamber

Woofer

Woofer Response
Woofer Horizontal Off Axis (15,30,45,60)

Woofer Vertical Off Axis (15,30,45,60)

Woofer Step Response

Woofer Impulse Response

Woofer Harmonic Distortion
Woofer Phase

Woofer Response Difference Between Both Speakers

Tweeter

Tweeter Frequency Response

Tweeter Horizontal Off Axis (15,30,45,60)
Tweeter Vertical Off Axis (15,30,45,60)

Tweeter Step Response

Tweeter Impulse Response

Tweeter Harmonic Distortion

Tweeter Phase

Tweeter Difference Between Speakers

El Palmisté by Alex Palma is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License.

Weathered Mannes’

Overview:

The Weathered Mannes’ are a pair of 2-way portable speakers.  They were designed to provide an accurate casual listening experience as well as the ability to accurately mix.  They feature a passive crossover system and vented enclosures.  The f3 of these speakers is 38Hz with the extension the port provides.  They were built with an interior layer of 3/4″ MDF and an exterior layer of 3/4″ Birch.

Drivers:

Peerless PPB 830874 Poly Cone Woofer

SEAS 27TDFC Textile Dome Tweeter

Documents:

Design Proposal

Drafting Overview

Final Crossover Schematic

Final Testing Report     Contains All Final Test Images

Glossy

wjfruin_Tekkonkreet

About Tekkonkreet

This two-way system, with a sealed box enclosure, was constructed using concrete and a wooden front baffle. The half cylinder was both a stylistic choice as well as one that would aid in fidelity. By making these speakers a misshapen cylinder, it decreased standing waves with in the box. The entire appearance was inspired by the urban decay around the Keweenaw Peninsula, in Michigan, after copper mining left. This left ruins from old mining structures around the area. Don’t let the appearance of these speakers fool you though, their performance is extraordinary.

• bandwidth 100Hz-10,000Hz +-4 db
• f3 @ 80Hz and f10 @ 60Hz

Design of Tekkonkreet

When I first conceived these speakers, I really just wanted to test to see if it could be done.  I wanted to find out if I could create a speaker system that was both made of concrete and a half cylinder in shape. Granted, at this point, my design was largely based on an experiment and appearance. In order to accomplish something that I would not only want in my home, but also something that I would hold on to for the rest of my life, I decided to make these a set of Hi-Fi home speakers.

transducerproposal

Final testing info

Drivers in Tekkonkreet

When considering drivers, I decided on the Fostex ft48d cloth dome tweeters and the Aurum Cantus AC 250 eight inch non-woven carbon fiber woofers.  These seemed to complement each other well.  In modeling, all I needed was a first order crossover to make them work together. Upon building the crossover, I realized that  a third order crossover at 2,500 Hz for both of them was needed.

Crossover For Tekkonkreet

After a great deal of testing first order and second order butter-worth crossovers, I decided on a third order bessel crossover at 2,500 Hz on the tweeter and a third order butter-worth on the woofer also at 2,500 Hz. My speakers had a gradual upward curve in the frequency response.  This was remedied with a set of three baffle step circuits which acted as low pass filters that made my speakers sound more bass heavy; thus, giving the illusion of having a lot of bass.

Conception of Tekkonkreet

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License.

Green Run: Critical Editing Speakers

What they lack in size they make up in clarity and versatility. Designed for

Green Run Right Cabinet

near-field desktop audio editing, these speakers are created to
reproduce the sound signal with maximum clarity.  Optimized and built
small to fit at any editing environment and portable for the nomad
lifestyle.

Design Objectives:

• Bookshelf monitors for audio editing for music, sound effects and film
• Wide frequency range (60 Hz to 20 kHz)
• Smooth frequency response
• Inexpensive

Green Run Left Cabinet

Key Features:

• Small, and portable
• Clear stereo image
• Minimal off-axis coloration
• Low crossover frequency of 1.5kHz
• Under $500

Design Statement

Tuning Report

Crossover Schematic

Cabinet Drafting Plans

System Response
Final System Response Charts Left Cabinet

Final System Response Charts Right Cabinet

SB Acoustics 29RDCN C-0004

Final Tweeter Response Charts Left Cabinet

Final Tweeter Response Charts Right Cabinet

Fountek FW 146

Final Woofer Response Chart Left Cabinet

Final Woofer Response Chart Right Cabinet

This work is licensed under a Creative Commons Attribution-No Derivative Works 3.0 United States License.

BB 2-Way Loudspeakers

A well balanced speaker with a low x-over by Ben Boeshans

The primary design goal of the speaker is all-purpose music speaker for everyday listening.  The speakers require good low-end extension, good clarity, and low fatigue.   The crisp highs were obtained through crossover points calculated to be 900 Hz for the woofer and 1.2 kHz for the tweeter.  The goal was met, as exhibited by the several peer reviews some of which commented, “extremely clear,” very accurate,” and “sounded really clean.”  I really like the sound of plucked guitar played on the speakers.  If one closes their eyes they can believe the guitar is being played in the same room.  Part of that effect is also attributed to the reverberation in the cabinets.  After experimenting with a few different types and amounts of damping materials a balance was found between the openness of the speaker and eliminating resonances.

Design Objectives

• All-purpose Music Speaker
• Tight Low-End Response
• 97dB SPL Max output
• f3 = 50Hz

Key Features

• Soft-dome tweeter for mellow yet clear highs.
• Low crossover point for fast transient response.
• 2” Port for bass extension.
• 8” Woofer for solid, defined low-end.
• MDF/Plywood layered cabinet for reduced resonance.
• Smooth frequency response 60Hz to 20 kHz.
• Accurate off-axis response.

Technical Reports

• BB_Design_Statement
• BB_Final_Report
• Testing Report
• Drafting
• X-over Schematic

Tests

Tweeter & Woofer Response

Step Response

Minimum Phase Response

Harmonic Distortion