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Sandcastle 7.2


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Designed by: Eric Bartos

Goals

  • 7.2 surround sound system for enjoyment and the occasional mix
  • +/- 4dB response
  • active crossover

Key Features

  • F3 of 38Hz on surround speakers (before crossover between subwoofer)
  • F3 of 34Hz on center speaker (before crossover between subwoofer)
  • F3 of 24Hz on subwoofers
  • +/- 4dB from 50Hz to 21kHz on surround speakers
  • +/- 4dB from 47Hz to 21kHz on center speaker
  • +/- 2dB from 25Hz to 200Hz on subwoofer
  • center speaker has active/passive crossover system
  • 1/2″ birch ply and 1/2″ MDF construction for center speaker and surround speakers
  • 1/2″ birch ply and 3/4″ MDF construction for subwoofers
  • BSS Blu-100 & BSS Blu-BoB for DSP

Drivers

  • Woofer: Dayton Audio RS225-8
  • Tweeter: Seas Prestige 19TFF1
  • Midrange (Center speaker only): Dayton Audio RS52AN-8
  • Subwoofer: Eminence LAB12-C

Frequency Response

Surround speakers

Surround Overall 60db range

Surround Integrated Response

surround integrated 40

Center Speaker

center response 60.png

Center Integrated Response

center integrated 40

Subwoofer

sub response 60

Sandcastle glossy

Sandcastle Research Paper

Sandcastle Final Testing

The Chickenfeet


IMG_4498

 

Design Goals

  • Sealed box
  • Tight low bass response
  • Easy to transport
  • Good off-axis
  • Unique paint job
  • For listening and mixing

Features

  • Diffusion panel inside of box
  • Great off-axis response
  • Dimensions 19.25″ x 10.5 x 21″
  • Cool paint job

SPEAKER2

SPEAKER3

T:W WATERFALL

 

Design Statement and Crossover Work

Drafting

JH Array


Introduction

Designing speakers is a battle of the minds. This battle can prove to be long and drawn out but when you reach the end it is very rewarding. There are so many different designs that can be implemented it is very challenging to select something and stick with it. As I have found out you can have a design and then see another design and immediately want to incorporate or change to the new design. I relate it to a kid in a candy store. The kid has his eye set on a jaw breaker going in but when all is said and done he walks out with a giant gummy bear. As long as the end product fully satisfies what you want it to than you have completed the mission.

Design Goals

The design for the JH Array came from a line array system. Working in live sound thats just about all you see and hear now. So I wanted to take what I listen to at work and make is sound better, look cooler and hang in my living room. In order to make them sound better I used quality drivers as well as solid box construction in order to get the sound I wanted. In order to make them look cooler I decided to go with a satin black center and bare wood sides this gave it contrast and some warmth that line arrays lack. Finally hanging in myliving room. I designed both boxes with anchor points so that it is possible for me to put some eye bolts into them and hang them from any rig point.

Features

  • All sealed boxes to provide good transient response
  • MTM speaker layout to provide good off axis listening
  • Frequency Response +/- 3dB

Drivers

  • Tweeter: ScanSpeak Illuminator D3004, 1” Soft dome
  • Mid Range: Peerless HDS 830883 6 1/2”, Nomex diaphragm
  • Subwoofer:TC Sounds Epic 12” DVC Subwoofer

Box Construction

  • Boxes built using constrained layer construction
  • Mid & Tweeter Box (outside going in)
    • 1) 1/2” Birch Ply(top, bottom, front and back)
      • 3/4” Baltic Birch(Sides)
    • 2) 3/4” MDF
    • 3) 1/8” Mass loaded vinyl
    • 4) 1/8” Masonite
  • Sub box
    • 1) 1/2” Birch Ply(top, bottom, front and back)
      • 3/4” Baltic Birch(Sides)
    • 2) 3/4” MDF
  • Rounded Sides
  • Screws only visible in the rear
  • Magnets in baffle for grills \
  • Sub bracing also supports voice coil

Final Results

Frequency Response

Horizontal Off Axis

Vertical Off Axis

Left Right Difference

Waterfall

Tweeter

Frequency Response

Horizontal Off Axis

Vertical Off Axis

Impulse

 

Mid Range

Frequency Response

Horizontal Off Axis

Vertical Off Axis

Impulse

Sub Woofer

Frequency Response

Horizontal Off Axis

Vertical Off Axis

Impulse

Crossover Response

Documents

Design Proposal

Testing Report

Enclosure Drafting

Crossover Design

MT1

April 27, 2012 Leave a comment

Over View

These speakers are designed for film and for fun! Keeping aesthetics as the main design goal, their main purpose is for cinema and for the ocasional house party. This led to important design goals that I wanted to keep different then any previous students. This included an acrylic baffle, a visible crossover so that you can see the inner workings of the speaker, and to top it off, LEDs to give it a little more sparkle. The acoustical properties that were my main goals were to have the capability of a wide dynamic range and an extended frequency range through the use of a transmission line.

Features

– 3 Way

– Passive Cross over

– 13 Foot Transmission Line

– Acrylic Baffles

– Interior LEDs

Cabinet

– 5′ 4″

– 2′ x 2′ Base

– 350 lb Each

– 3/4″ MDF interior

– 3/4″ Red Oak Exterior

Drivers

– Tang Band RT-1516SA Ribbon Tweeters

– 3″ Tang Band 75-1558SE Dome Drivers’

– 12″ TC Sound Epics

Coast

~ $3500

Documents

Final report

Final Measurements

Speaker Glossy

Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

Testing Results

Frequency Response

Horizontal Off Axis

Vertical Off Axis

Left/Right Difference

Tweeter 

Frequency responce

Horizontal off axis

Vertical off axis

Impulse Response

Phase

Midrange 

Frequency Response

Horizontal Off Axis

Vertical off axis

Impulse Respose

Phase

Sub

Frequency Response

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


El Palmisté

April 19, 2011 Leave a comment

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

not a big deal

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

Creative Commons License

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


FrankenSound by Justin Boldenow

April 7, 2011 1 comment

General Overview:

I was drawn to the openness and clarity of electrostatic drivers and a dipole system. I chose to build the large coffin-like subwoofer enclosures so that the 15” drivers would be capable of reaching mid-range frequencies and the lowest ends of human hearing. The coffin look is both interesting and functional as unusual shaped enclosures diffract frequencies and help disperse stored energy.

Design Goals:

My first and foremost desire was for monitors that had enough bandwidth, clarity and accuracy to be used as mixing monitors. The electrostatic drivers came with clarity and accuracy so I wanted to design enclosures that could match this and supply the rest of the frequency range needed. I wanted to cover the range of human hearing from high to low accurately.

Design objectives:

• Even full-range frequency response

• Low harmonic distortion

• Dipole system

• Completely original design

Key Features:

• 2-way crossover with potential of 3-way

• Passive crossover with potential of adding an active crossover

• dipole sub/mid woofer enclosure for extended low frequency response and “air”

• Electrostatic tweeters

• Coffin shaped design

• Chalkboard paint

Technical Specifications:

• Bandwidth 25 Hz-20kHz, +- 4 dB

• Max SPL 85 dB with 20 dB headroom

• f3 30 Hz

• f10 16 kHz

Cabinet Construction:

My cabinets are made out of 3/4 inch 13 ply baltic birch plywood and 3/4 inch MDF, this was done to keep the structure solid. Plywood was chosen because of its construction with alternating grain. The MDF’s density helps deaden the cabinet.

The Subwoofer cabinets were designed to be large so as to achieve lower end frequencies. The larger the box was, due to its dipole characteristics, the more resonance it had at lower frequencies. This was done to achieve low frequencies with just a 15in driver instead of using larger drivers and sacrificing mid-frequencies. The coffin design is an irregular shape which helps to disperse stagnant energy held within cabinets. It also fits my personality.

Tweeter:

I chose the Final Sound electrostatic speakers and built the rest of my system to fit it. I chose these drivers because they covered high frequencies and high midrange, which would save me costs in midrange drivers. I also chose these drivers because of their dipole nature and incredible transient qualities. Though the driver wasn’t the flattest in response I believe this can be cured with acoustic tuning of the room that they are placed in. Unfortunately, a standard crossover would not work on these because their impedence nature  had a completely different curve in testing. They were left with the natural crossover that they were manufactured with.

Subwoofer:

For the subwoofer I went with the only infinite baffle designed drivers I could find. The Dayton IB’s were specifically engineered for dipole use and their sound is incredible. Unfortunately the drivers themselves were designed to reach 40 Hz which didn’t fit my requirements. This is why I built such large boxes and gained another 15 Hz lower.

Cross-over:

As I stated before, a standard crossover would not function on the electrostatic drivers and were left to function with their natural manufactured crossover. This implies that I only needed to build a crossover for one driver and the crossover was the simplest crossover to create. I used a 1st order Butterworth at 100 Hz. I chose this frequency because it was roughly where the electrostatic ended and where the subwoofer began to slope downward slightly. Though the total frequency response of the system looks a little rough, I plan to correct a lot of it with acoustically treating its environment and experimenting with black-hole fiberglass/foam.

Testing:

Overall Speaker Performance:

Frequency Response

Harmonic distortion

Step Response

Off Axis Response

Frequency response with individual drivers overlayed

Green is the overall response, Yellow is the subwoofer and Red is the tweeter

Tweeter Performance:

Frequency Response

Subwoofer Performance:

Frequency Response