Shriek Mk. I Speaker Design

Transcription

1 Shriek Mk. I Speaker Design Steve Green FA 4740 Spring 2014 Semester Loud Speaker Design Plans Michigan Technological University [TYPE TEXT] [TYPE TEXT] [TYPE TEXT]

2 Table of Contents Functional Description... 3 Design Goal Statement... 3 Purpose... 3 Environment... 3 Audio Characteristics... 3 Portability:... 3 Visual Aesthetics... 4 Visual Aesthetics Statement:... 4 Material:... 4 Dimensions:... 4 Protection:... 4 Paint:... 4 Cabinet Design... 5 Shape:... 5 Bracing & Wall Strength:... 5 Wall Relationships & Edge Diffraction:... 5 Prioritization... 5 Golden Ratio:... 6 Technical Goals... 6 Technical Goal Statement... 6 Size & Weight... 6 SPL Standards... 7 Speaker Sensitivity... 7 Personal Standards... 8 Frequency Response... 8 Low Frequency Response... 8 High Frequency Response... 8 Shape and Voicing... 9 Coloration and Time Response... 9 Dispersion... 9 Drivers... 9 Woofer Selection... 9 Tweeter Selection Drafting Shriek Mk. I Testing Report Overall Loudspeaker Performance Individual Drivers Speaker Glossy Bibliography Shriek Mk. I Transducer Design 2

3 Functional Description Design Goal Statement Reach comfortable mixing levels Produce high fidelity mixing speakers Portable size: Large enough to support 8 drivers but maneuverable to new locations Price Range: ~$ Purpose These loudspeakers will serve as general mixing speakers for various projects including, but not limited to: video games, music and movies. I believe they will be used most often for video game sound effect synthesis and mixing. Environment The loudspeakers will be maneuverable to various locations to account for the unpredictability of a sound designer s job. Environments may include anything between medium sized rooms 1 to large open areas. Audio Characteristics The primary purpose for these speakers will be general mixing. With this in mind they will be prioritizing a Hi Fidelity sound rather than personal enjoyment. My high frequency response goal is around 20KHz. My low frequency requirement should be around 50 Hz. Both of these values were determined through a course of personal experiments to determine my personal preferences. My SPL preference based off experiments must be able to comfortably reach about 85 db SPL. I hope to have headroom though somewhere in the 90 db SPL range. Portability: The speakers must be portable with the mobility mind set in place. The variable in this is the frequency in which they will be moved. Considering this I would like them to feel stationary when first looking at them, but attachable or removable parts will make them easier to move. 1. Common Room Sizes. room- sizes/ (accessed Jan 17, 2014). Shriek Mk. I Transducer Design 3

4 Visual Aesthetics Visual Aesthetics Statement: My plan is for these speakers to be different from the typical matted black speakers commonly used in theater and other applications where speakers are wanted invisible. I plan for these speakers to stand out. The overall aesthetics will also reflect my portability mindset. Material: ¾ ply wood for the basic construction of the box. I will then apply a ½ outer layer of MDF to help with stability and overall aesthetics of the speakers. Dimensions: The speaker s dimensions should be around 17.5 tall by around 14.5 deep with a width of about These dimensions are loosely based off already made professional cabinet sizes such as the Yamaha HS8 2 and Lindsey John s previously made Euphony Blues 3. Protection: I will not use a grill when the speakers are set up, though I will create a front face that will be attachable once the speakers are ready to be moved. The creation of this front face will be determined after the speakers have been created. Paint: The loudspeakers will be painted a glossy white. How to obtain the glossy finish though is yet to be decided. I also plan to add my Shriek Studios 4 logo onto the speaker at various positions to help advertise myself. 2 N/A. "HS8." - HS Series. production/speakers/hs_series/hs8/?mode=model (accessed Jan 17, 2014). 3 Johns, Lindsey. Tech Speakers - Michigan Tech FA 4740 Loudspeakers - Euphony Blues. (accessed Feb 2, 2014). 4 Green, Steven. Steven M. Green Shriek Studios - Home. (accessed Jan 17, 2014). Shriek Mk. I Transducer Design 4

5 Cabinet Design Shape: These speakers will be of a vertical rectangle with one woofer and one tweeter. The reason behind the shape is due to the fact that rectangles have come to be the most convenient shape when creating speakers. 5 I will be severely rounding the edges of the speakers as well. Bracing & Wall Strength: I will be bracing the speaker box with at least 1 brace within the box. The brace will also serve as a wall to separate the rear mounted mini dsp amp as well as have black hole sound dampening material mounted to it. Wall Relationships & Edge Diffraction: Any and all bracing will be rounded to reduce wall reflections 6. Internal muffling will also be used to reduce noise reflections. Wood glue, caulk and various types of nails will join the walls and bracings themselves. Prioritization Hi Fidelity is my first priority. I am looking to achieve ±1.5dB across the 50Hz to 20kHz range. My second priority is size. These speakers must be at least somewhat portable to showcase and work on projects under various circumstances. My final priority is SPL. I wish to reach at least 85 db SPL with hopefully 5 to 10 db SPL of headroom. 5 Sabolish, Michael. Speaker Cabinets. (accessed Jan 17, 2014). 6 LaLena, Michael. Speaker Box Design Example. (accessed Jan 17, 2014). Shriek Mk. I Transducer Design 5

6 Golden Ratio: In order to reduce resonance within the box I will be attempting a method of using mostly all prime numbers for internal wall sizes. By using these numbers I should be able to minimize frequencies of resonance as they are not easily created in multiplications. Technical Goals Technical Goal Statement My technical goals are mainly to achieve a studio pair of hi fidelity loudspeakers that can be used for various mixing of audio projects. This means achieving a frequency response of about 1.5 db between the 50Hz to 20 khz range. At the same time these speakers must be portable. SPL is of low priority but these speakers should comfortably reach about 85 db SPL. Size & Weight Height: 17.5 Width: 14.5 Depth: 11.5 Weight: 20 to 30 lbs From carrying similar objects around, I ve found about 30 pounds is at the top of my comfortable carrying limit. However this weight is made easier once handles or a method for which I can handle the object is put into play. Shriek Mk. I Transducer Design 6

7 SPL Standards K 20: For dynamic range fitting to the demands of film mixing. This is my primary basis for my SPL goal, which is to have 83 db for my 0 with 20 db of headroom, making my goal a peak of 103 db. Speaker Sensitivity dbw 83 dba in order to meet 0 for K"20 dbw = 10log(x) x = 100 Watts dbw = 20dB The K 20 standard requires speakers to be able to reach 83 db but add another 20 db of headroom. In order to reach this, I will be using a 100 watt amplifier which should go beyond my wanted peak goal of 95 db SPL. According to NIOSH recommendations, 88 dba is the first measurement where hearing loss can be found. With my goal of 85 db SPL, hearing loss could be a factor, however it will be of low concern to me as I do not plan to use these speakers beyond that level. Shriek Mk. I Transducer Design 7

8 Personal Standards Frequency Response -My goal frequency response 50Hz 20KHz ±1.5dB My low frequency preferences are based on my personal findings below. General Low Frequency Perception: -Noticeable low frequency loss: 25Hz -Still Doable: 45 Hz -Unacceptable low frequency loss: 70 Hz Low Frequency Response Low frequency goals generally pertain to sound effects as well as music. -Bass Guitar (41Hz) -Kick Drum (50Hz) -Sound Effects (40 Hz) High Frequency Response High frequency response is based off of speaking voices, soundtrack music. -Sound Effects (20KHz) -Voices (16KHz) Shriek Mk. I Transducer Design 8

9 Shape and Voicing With the intent of these speakers being used for general mixing, I aim to achieve a flat frequency response across my desired spectrum. A large amount of perceived bass boost would greatly detract from the purpose of these loudspeakers. Coloration and Time Response These loudspeakers will be designed to minimize coloration and listening fatigue. The design should roll off low and high frequencies evenly. Though to reach lower Mounting and Positioning These loudspeakers will most often be placed onto a desktop at a distance of around 1.5 to 2 meters apart, angled at either a single or a pair of listeners between 1 to 2 meters away at any given time. Though I do not plan to use any sort of mounting, I d like to leave the option to do so available at this time. Dispersion Designed for a relatively near listener, the loudspeakers will need only a relatively narrow dispersion. However, keeping in mind there may be more than one listener, the dispersion must be acceptable to about 45 degrees off center. Drivers Woofer Selection Shriek Mk. I Transducer Design 9

10 Dayton Audio 7 RS225-4 Specifications: Cost: $48.00 Size: 8 +/- 2 In Bandpass 150 Hz to 1K Hz Breakup Starts at: 1K Hz Breakup Amplitude Peak: 8 db Recommended Crossover: 3 rd Order at 1K Hz 8 7 Dayton Audio Editors. Dayton Audio RS components/loudspeaker- drivers- by- series/reference- series/rs reference- woofer- 4- ohm.html (accessed 3 3, 2014). 8 This is my recommended crossover due to the very erratic frequencies given by the woofer after 1K Hz. Shriek Mk. I Transducer Design 10

11 Assessment: The Dayton RS225-4 is an 8- inch woofer I have recently decided to model. It turns out to have a great low frequency range with a very minor boost being needed to reach levels below 50 Hertz in a very small box. The driver itself is cheap and is becoming a quick favorite of mine. I have yet to find many downsides yet other than its high end only barely reaches 1,000 Hertz comfortably. Fountek 9 FW200 Specifications: Cost: $60.45 Size: 8 +/- 2 In Bandpass 100 Hz to 900 Hz Breakup Starts at: 1K Hz Breakup Amplitude Peak: 7 db Recommended Crossover: 3 rd Order at 1K Hz 10 9 Fountek Electonics Co. Fountek FW (accessed 2014 йил 15- Feb). 10 This is my recommended crossover because of the break up frequencies after 1K Hz Shriek Mk. I Transducer Design 11

12 Assessment: The Fountek FW200 Woofer has been my favorite up until this point with his awesome low frequency response and nice design. However the fact that it has been outperformed means more to me than how it looks. It is also a little more on the expensive side as far as my woofers have been going. Aurum Cantus 11 AC180/50C2C Specifications: Cost: $97.00 Size: 7 +/- 2 In Bandpass 70 Hz to 900 Hz Breakup Starts at: 1K Hz Breakup Amplitude Peak: 5 db Recommended Crossover: 4 th Order at 1K Hz Aurum Cantus Editors. Aurum Cantus AC180 50C2C. express.com/pedocs/specs/ aurum- cantus- ac18050c2c- specifications.pdf (accessed 3 3, 2014). 12 This is my personal crossover because of how sharply the frequency drops off. Shriek Mk. I Transducer Design 12

13 Assessment: The Aurum Cantus had a great frequency response chart but upon actually modeling it, it has a very quick drop off after reaching its lowest frequencies. The problem I faced with it though was its size and the company behind it. I don t necessarily agree with their business practices and don t really care to be buying their products. This particular driver is also on clearance at most retailers though which leads me to believe it will be done away with, meaning future replacements would be harder to find. HiVi 13 M8N Specifications: Cost: $34.86 Size: 8 +/- 2 In Bandpass 100 Hz to 1K Hz Breakup Starts at: 1K Hz Breakup Amplitude Peak: 9 db Recommended Crossover: 4th Order at 1.5K Hz HiVi Editors. HiVi M8N. express.com/pedocs/specs/ hi- vi- m8n- specifications pdf (accessed 3 3, 2014). Shriek Mk. I Transducer Design 13

14 Assessment: This woofer is interesting as it has a great low- end response with a ported design. However I can t stand the aesthetics of it. I was able to get a lower end out of a different driver too, which drew me further away from this woofer Dayton Audio 15 RS Specifications: Cost: $42.00 Size: 7 +/- 3 In Bandpass 150 Hz to 1K Hz Breakup Starts at: 1K Hz Breakup Amplitude Peak: 6 db Recommended Crossover: 3 rd Order at 1K Hz 16 Assessment: The Dayton RS180-4 was a woofer I decided to model after seeing how well the other Dayton Audio woofer performed. It gave me a great low shelf response but wasn t able to surpass the Dayton RS This is my recommended crossover due to how sporadic the response plot becomes. 15. Dayton Audio RS express.com/pedocs/specs/ dayton- audio- rs specifications pdf (accessed 3 3, 2014). 16 This is my recommended crossover point. Shriek Mk. I Transducer Design 14

15 Tweeter Selection Vifa 17 NE19VTT- 04 Specifications: Cost: $34.21 Size: ¾ +/- 2 In Bandpass 800 Hz to 4K Hz Breakup Starts at: 10K Breakup Amplitude Peak: 5 db My tweeter selection has varied across a number of tweeters. However the one I will be using will be the Vifa NE19VTT- 04 as it seems to have the best low and high ends at the best cost. The tweeter is ¾ big. It will match my woofer nicely. I also enjoy the aesthetics of it though wish it were all black to match my woofer selection. 17 Vifa Co. Vifa NE19VTT dome- tweeter/vifa- ne25vta- 1- aluminum- dome- tweeter- 4- ohm/ (accessed 2014 йил 15- Feb). Shriek Mk. I Transducer Design 15

16 Vifa 18 XT25TG30-04 Specifications: Cost: $32.90 Size: 1 +/- 3 In Bandpass 200 Hz to 2K Hz Breakup Starts at: 3K Breakup Amplitude Peak: 10 db I had also considered the Vifa XT25TG30-04 however its frequency range did not suit what I would have liked to do with it. It just didn t compare with the other tweeters I was considering. The price was a good match for the tweeter but it breaks up far too quickly as it reaches its high end. 18. Vifa XT25TG express.com/pedocs/specs/ vifa- xt25tg specifications pdf (accessed 3 4, 2014). Shriek Mk. I Transducer Design 16

17 Vifa 19 Vifa NE25VTS- 04 Specifications: Cost: $32.90 Size: 1 +/- 3 In Bandpass 200 Hz to 2K Hz Breakup Starts at: 3K Breakup Amplitude Peak: 10 db I also tried to use the Vifa NE25VTS- 04, however again this Vifa tweeter did not reach what I had hoped it would reach in terms of low frequency and steady high frequencies. 19. Vifa NE25VTS express.com/pedocs/specs/ vifa- ne25vts- 04- specifications pdf (accessed 3 4, 2014). Shriek Mk. I Transducer Design 17

18 Dayton Audio 20 ND25TA- 4 Specifications: Cost: $18.85 Size: 1 +/- 3 In Bandpass 200 Hz to 2K Hz Breakup Starts at: 3K Breakup Amplitude Peak: 10 db I also attempted to stay with a single brand, in doing so I looked at the Dayton Audio ND25TA- 4. The major problem with this tweeter though is that it does not go very low at all. It came off as a fairly cheap tweeter. The break up pattern seemed fluid enough but overall the driver came off to me as a very poor tweeter. 20. Vifa ND25TA express.com/pedocs/specs/ s.pdf (accessed 3 4, 2014). Shriek Mk. I Transducer Design 18

19 Vifa 21 D27TG35-06 Specifications: Cost: $28.00 Size: 1 +/- 2 In Bandpass 1.5K Hz to 15K Hz Breakup Starts at: 10K Breakup Amplitude Peak: 5 db A final tweeter I had looked at was the Vifa D27TG Similar to the other Vifa, I liked the aesthetics better but it performed a little under what the other Vifa could do. It broke up far too quick but at high frequencies. However leading up to its flat rate, it doesn t start leveling off until its pretty high up. 21. Vifa D27TG express.com/pedocs/specs/ vifa- d27tg specifications.pdf (accessed 3 4, 2014). Shriek Mk. I Transducer Design 19

20 I ended up going with the Dayton Audio RS- 225 woofer and Vifa NE19NT tweeter. For their prices and their frequency response plots, I felt they were by far the best value for their prices. Dayton Audio RS- 225 with Vifa NE19NT Tweeter Crossover Chart 120& Tweeter Tweeter&Crossover Woofer Woofer&Crossover Sum & 100& 90& 80& 70& 60& Tweeter& Tweeter&Crossover& Woofer& Woofer&Crossover& Sum& 50& 40& 500& 1000& 2000& 3000& 4000& 5000& 6000& 7000& 8000& 9000&10000& Shriek Mk. I Transducer Design 20

21 " " " " " " " " 3 4 " 3 8 " 1 2 " 1 4 " 1 2 " 34" 16" " 1' " 1'-2" 1' " 1' 1" 1 2 " 1 4 " 1 4 " 9 16 " 1 4 " 1 4 " 1 2 " " 3 8 " 3 8 " 3 4 " 3 4 " 3 4 " " 9" Steven Green Drafting 1 2 " MDF Top/Bottom Outside 1'-2" 3 8 " Plywood Front/Back Inside " 3 4 " Internal Bracing " 1' " 1'-3" " " 2 " 3 4 " 1 4 " 1 4 " Left/Right Outside 1' " 3 8 " 3 4 " 1'-3" " 2 3 1' " 1' " " 1'-3" 1' " Left/Right Inside 1'-1 12" 1' " " Draft Steve Green FA 4740 Shriek Mk. I Notes: 3/4" Plywood 1/2" MDF 1" Black Hole 1' " 1' " Front/Back Outside " " 1'-3" 1' " Top/Bottom Inside 1' " Cut Sheet Cuts Left Speaker Internal L Left Speaker Internal R Right Speaker Internal L Right Speaker Internal R Left Speaker Internal Brace Right Speaker Internal Brace Left Speaker Left Speaker Right Speaker Right Speaker Internal Front Internal Back Internal Front Internal Back Left Speaker Bottom Left Speaker Top Right Speaker Bottom Right Speaker Top Plywood MDF Cut Sheet Left Speaker External Bottom Left Speaker External Top Right Speaker External Bottom Left Speaker External Top Left Speaker External L Left Speaker External Front Left Speaker External Back Right Speaker External Front Right Speaker External Back Left Speaker External R Right Speaker External L Right Speaker External R Shriek Mk. I Transducer Design 21

22 Shriek Mk. I Testing Report My goal was to create a speaker with a +/- 1.5 db response between 50 Hz and 19,000 Hz. My initial testing, shown below showed my speakers had about a +/- 4 response between those frequencies as a start. The major problems being near the crossover and where the box resonated. Through my testing, I typically kept the testing equipment at about 16 to 24 inches from the speaker. While 1 meter is typically the average, I found I had been receiving a lot more room noise than direct speaker sound when at that distance. Initial Testing: Overall Loudspeaker Performance Frequency Response: Shriek Mk. I Transducer Design 22

23 Integrated Response: Harmonic Distortion: Minimum Phase: Horizontal Off- Axis: Shriek Mk. I Transducer Design 23

24 Vertical Off- Axis Difference Plot: Step Response: Integrated Step Response: Shriek Mk. I Transducer Design 24

25 Impulse Response: Waterfall Plot: Shriek Mk. I Transducer Design 25

26 Individual Drivers Woofer Frequency Response: Harmonic Distortion: Shriek Mk. I Transducer Design 26

27 Minimum Phase: Horizontal Off- Axis Vertical Off- Axis: Step Response: Shriek Mk. I Transducer Design 27

28 Impulse Response: Tweeter Frequency Response: Harmonic Distortion: Shriek Mk. I Transducer Design 28

29 Minimum Phase: Horizontal Off- Axis Vertical Off- Axis: Step Response: Shriek Mk. I Transducer Design 29

30 Impulse Response: Shriek Mk. I Transducer Design 30

31 Steven Green Speaker Glossy Steve%Green% Shriek'Mk.'I' The$Shriek$speakers$are$built$with$high$fidelity$in$mind.$They$ will$typically$be$used$in$a$studio$setting$for$the$creation$and$ mixing$of$sound$effects$and$dialogue.$$they$have$a$frequency$ response$accurate$to$within$1.5$db$between$70$to$1,9000$hz.$but$ can$reach$as$low$as$40$hertz$depending$on$room$size.$the$mk$i s$ have$a$very$crisp$sound$but$have$little$to$no$listening$fatigue.$$due$ to$their$shape,$dispersion$is$almost$unnoticeable$to$within$45$ horizontal$degrees$off$axis.$they$use$the$mini$dsp$active$ crossovers,$with$which$they$can$be$tuned$easily$to$whatever$room$ they re$placed$in$and$don t$require$a$separate$amp.$$ $ +/-'1.5'dB'between'70'&'19,000Hz$ Very'Low'Listening'Fatigue' Very'Wide'Dispersion' Mini' DSP' ICE-125' Amp' /' Active''''''''''''''''''''' Fourth'Order'Crossover' ~40'Pounds' Dayton'Audio'RS-225'Woofer' Vifa'NE19VTT-04' $ Shriek Mk. I Transducer Design 31

32 Bibliography Aurum Cantus Editors. Aurum Cantus AC180 50C2C. express.com/pedocs/specs/ aurum- cantus- ac18050c2c- specifications.pdf (accessed 3 3, 2014). Calculator for Closed Back Cabinets Using One Speaker. Weber Vintage Sound Technology (accessed 2014 йил 6- Feb). Co., Jinglang Audio. AC180/50C2C Woofer. download/pdf/ac180%2050c2c.pdf (accessed 2014 йил 15- Feb). coursegraphics. (accessed 2014 йил 17- Jan). Dayton Audio Editors. Dayton Audio RS components/loudspeaker- drivers- by- series/reference- series/rs reference- woofer- 4- ohm.html (accessed 3 3, 2014).. Dayton Audio RS express.com/pedocs/specs/ dayton- audio- rs specifications pdf (accessed 3 3, 2014). Dickason, Vance. The Electrostatic Loudspeaker Design Cookbook. Peterborough, N.H.: Audio Amateur, Fountek Electonics Co. Fountek FW (accessed 2014 йил 15- Feb). Fountek Electronics Co. Fountek Neo X (accessed 2014 йил 15- Feb). Green, Steven. Steven M. Green Shriek Studios - Home. (accessed 2014 йил 17- Jan). HiVi Editors. HiVi M8N. express.com/pedocs/specs/ hi- vi- m8n- specifications pdf (accessed 3 3, 2014). Johns, Lindsey. Tech Speakers - Michigan Tech FA 4740 Loudspeakers - Euphony Blues. (accessed 2014 йил 2- Feb). LaLena, Michael. Speaker Box Design Example. (accessed 2014 йил 17- Jan). N/A. "HS8." - HS Series. production/speakers/hs_series/hs8/?mode=model (accessed 2014 йил 17- Jan). Shriek Mk. I Transducer Design 32

33 . AES Standard on Acoustics - Sound Source Modeling - Loudspeaker Polar Radiation Measurements. (accessed 2014 йил 17- Jan).. Common Room Sizes. room- sizes/ (accessed 2014 йил 17- Jan). Newell, Philip, and Keith Holland. Loudspeakers For Music Recording And Reproduction. Amsterdam, MA: Focal Press. Plummer, Christopher. FA 4740 Transducer Theory. Houghton, MI: Michigan Technological University, Sabolish, Michael. Speaker Cabinets. (accessed 2014 йил 17- Jan). Vifa Co. Vifa NE19VTT dome- tweeter/vifa- ne25vta- 1- aluminum- dome- tweeter- 4- ohm/ (accessed 2014 йил 15- Feb). Vifa Editors. Vifa 25VTS express.com/pedocs/specs/ vifa- ne25vts- 04- specifications pdf (accessed 3 4, 2014).. Vifa D27TG express.com/pedocs/specs/ vifa- d27tg specifications.pdf (accessed 3 4, 2014).. Vifa ND25TA express.com/pedocs/specs/ s.pdf (accessed 3 4, 2014).. Vifa NE25VTS express.com/pedocs/specs/ vifa- ne25vts- 04- specifications pdf (accessed 3 4, 2014).. Vifa XT25TG express.com/pedocs/specs/ vifa- xt25tg specifications pdf (accessed 3 4, 2014). Shriek Mk. I Transducer Design 33