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CSS-616 Near-Field Mixing Monitors

March 23, 2016 Leave a comment

IMAG1566_1

Designed by: Courtney Schumaker

 

Design Goals:

• Mixing monitors for home studio

• Small to medium size for portability

• Accurate reproduction of sound, flat frequency response

 

Key Features:

• Portable

• Vented cabinet for low frequency extension

• Passive Crossover (Tweeter: 3rd order @ 1.6kHz, Woofer: 4th Order @ 2kHz)

• +/- 2dB Frequency Response

 

Drivers:

• Pearless Nomex 830869 – 8″ Woofer

• SB Acoustics SB26STAC-C000-4 – 1″ Textile Dome Tweeter

 

Frequency Response:

Screen Shot 2016-03-23 at 9.09.21 PM

 

Integrated Frequency Response:

Screen Shot 2016-03-23 at 9.11.33 PM

 

Horizontal Off Axis Response:

Screen Shot 2016-03-23 at 9.17.37 PM

 

CSS-616 Design Research

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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.


Two Towers by José Cordero-Medina

April 20, 2010 Leave a comment

Unfinished Loudspeaker

Left-Right speakers capable of full frequency range and meeting Dolby standards for cinema playback. Designed to provide a cheaper replacement to the current sound system in Walker 134. Center channel also designed, not yet built.

Overall Design Goal:

Provide Dolby standards for cinema playback to Walker 134. System capable of outputting 85dB SPL at audience distance with a 20dB headroom and an additional 10dB for the Low Frequency Effects unit.

Cabinet Construction:

5-sided box removes parallel surfaces reducing resonance in particular frequencies while also providing directional sound for maximum even coverage. 3/4 in layer of 13ply plywood outer layer and 1/2 in inner layer of MDF combine to provide rigidity to the cabinet as well as support for its size of 5’5″.

Drivers:

Each of the drivers were first and foremost chosen for its sensitivity and secondly for its compatibility with each other. Unfortunately, not all have perfectly flat response, reducing the overall frequency response balance, thus not making them suitable as professional mixing speakers. They do offer great sounding playback worthy of cinema speakers.

Cross-Over:

Very simple design with some additional parts for driver attenuation. The tweeter has a 1st order Buttersworth at 1.8kHz crossing over to the midrange with a 3rd order Buttersworth at 1kHz. The tweeter has a baffle step correction above 4kHz of -5dB, the midrange has a -3dB pad and the entire cross-over has a -6dB pad. The midrange rolls off naturally at the bottom end. The woofers have an interesting testing error cross-over that ended up working. As testing and tuning went by, I was changing the crossover from a 3rd order Buttersworth at 150Hz to 100Hz. I changes the capacitors, but not the inductors. Not sure what kind of cross-over it really is now, but it did what I needed it to, so I left it. It also has a notch filter at 200Hz to get rid of an overlap with the midrange driver.

<a rel=”license” href=”http://creativecommons.org/licenses/by-nd/3.0/us/”><img alt=”Creative Commons License” style=”border-width:0″ src=”http://i.creativecommons.org/l/by-nd/3.0/us/88×31.png&#8221; /></a><br /><span xmlns:dc=”http://purl.org/dc/elements/1.1/&#8221; href=”http://purl.org/dc/dcmitype/Sound&#8221; property=”dc:title” rel=”dc:type”>Michigan Tech Transducer Theory Dolby Speakers</span> by <span xmlns:cc=”http://creativecommons.org/ns#&#8221; property=”cc:attributionName”>Jose Miguel Cordero Medina</span> is licensed under a <a rel=”license” href=”http://creativecommons.org/licenses/by-nd/3.0/us/”>Creative Commons Attribution-No Derivative Works 3.0 United States License</a>

System Tests:

Frequency Response

Driver Responses

X-Over Responses

Harmonic Distortion

Horizontal Frequency Response

Step Response

Minimum Phase Response