EE / Mu 107 Project

EE / Mu 107 Project

 

Update: As of April 2011, 2 of the 4 subwoofers built through this project have returned home to Ricketts Hovse.

GROUP MEMBERS:

Lu Gan (right)

Christoph Baranec (middle)

Ben Gudlewski (left)

 

PURPOSE:

We have undertaken this project to design a speaker using an 18 inch driver. It will function as the main bass unit or woofer in a full-range speaker setup. Its main purpose is to reinforce the low frequency sounds that are usually inadequately reproduced by smaller drivers. The background for the speaker design was based on The Loudspeaker Design Cookbook, written by Vance Dickason. To facilitate simulations of frequency response curves, we used the MS Excel spreadsheet and equations written by Brian Steele @ www.diysubwoofers.org (Readme) (XLS).

 

MATERIALS AND METHODS:

The following materials were used or consumed in construction:

            Driver:

                        18” Dayton Audio Cast Iron Driver, [295-085, PE*, $150].

            Panels:

                        1” MDF2, sold in 49” x 97” sheets, 120 Lbs per sheet [CWS, $60/sheet].

            Panel Damping Material:

                        Soundcoat self-adhesive sheets, sold in XX” x YY” sheets. [SC, $XX]

            Internal Damping Material:

                        Dacron Fiberfill, sold in rolls, 5 Lb., [SC, $XX per 10 Lb. Roll].

            Handles:

                        Black steel, recessed bar handles, [SH-3025, SC, $6.60].

            Ports:

6” PVC Pipe. Outer diameter: 6 5/8”, Inner Diameter 5 XX”, [OSH, XXX$/foot].

            Speaker – Neutrik Cable:

                        Monster Cable OMC (10 gauge), 3 ft. [GG, $1.30/foot].

            Connector:

Neutrik SpeakonÒ 4NFLC female receptacle, round end, [092-054, PE, $5].

            Grills:

                        18” 1.1mm thick square mesh, [260-397, PE, $11].

            Corners:

                        2” Black steel corners, 4 [SC, $2.90].

            ¼ – 20 Bolts:

Length

Usage

# Needed

Retailer, Price

1.5”

Handles

40

CWS, $0.1 each

Driver

8

CWS, $0.1 each

2.25”

Grill

4

CWS, $0.1 each

            T – Nuts:

Length

Usage

# Needed

Retailer, Price

¼”

Driver

8

OSH, $0.35 each

½”

Handles, Grill

44

SC, $0.12 each

            Screws:

Type

Usage

# Needed

Retailer, Price

1” self-tap

Neutrik connector

4

CWS, $1.22 / box of 100

½” self-tap

Corners

24 (6 each)

CWS, $1.22 / box of 100

2” dry wall

Panels

Lots

 

            Glue:

                        Carpenter glue, ~ 1/16 gallon. [CWS, $2.00 / gallon].

            Caulk:

                        Silicone Caulk 2, ½ tube. [SR, $2.00 / tube].

 

* Vendor abbreviations are as follows:

            PE = Parts Express

            SC = Speaker City

            CWS = Caltech wood shop

            OSH = Orchard Supply Hardware

            SR = Sears

            GG = Good Guys

 

The following tools were used in the construction:

            Bulk panel cutting:

                        XXXX Table circular saw with YYYY blade.

            Large hole cutting:

                        Rotozip spiral drill.

            Small hole drilling:

                        XXXX vertical drill press.

                        XXXX air power hand drill.

            Smoothing:

                        Various files.

                        XXXX air power sander.

                        XXXX vertical power sanding belt.

           

 

PHOTO DOCUMENTATION:

We documented the construction and testing of the speaker with a digital camera:

            Assembly 1

            Assembly 2

            Assembly 3

            Brace

            Sides

            Sides w/bad handle placement

            Front

            Front w/ports

            Front w/ports 2

            Front w/driver

            Finishing 1

            Finishing 2

            Finishing 3

            Semi-Final Product

 

DESIGN:

This AutoCAD 2000 drawing shows the actual dimensions of all components.

            Woofer Board

            Panel Cutouts

            Soundcoat Cutouts

            Soundcoat Application

 

PHYSICAL CHARACTERISTICS:

Mass: 90 kg

Dimensions: 35” wide, 28” high, 22.5” deep

Estimated materials cost: $350