Subjective Comparison of Vocal Microphones
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Subjective Comparison of Vocal Microphones

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A short overview of objective microphone characteristics, and an introduction to some online resources for the subjective comparison of vocal microphones. ...

A short overview of objective microphone characteristics, and an introduction to some online resources for the subjective comparison of vocal microphones.

RELEVANT LINKS:
bradfordswanson.com/mic
3daudioinc.com
rodemic.com/soundboothstudio
shure.com/americas/support/tools/mic-listening-lab
eu.audio-technica.com/en/support/listen/

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  • Before we have an educated discussion about microphones, we should clearly define some of the terms that we will use. Understanding microphone specifications can help you make more meaningful decisions about your microphone choices, placement, and eventually purchase.
  • -We are familiar with the "basic" polar patterns, but every microphone is slightly different-How are these measured? -Static sine-waves at 5-12 different frequencies, Point source loudspeaker, Anechoic chamber
  • Electrical Construction & Transducer Technology-Condensor-Ribbon-DynamicDiaphragm Construction-Large vs. Small (and subtlties in between)-Diaphragm Material (thickness, mass, sputtering metal and technique)Grill construction-something has to protect the element!-they sound different!
  • Designed for specific instruments and sources with specific timbral or performance qualities in mind (a certain EQ curve or max SPL) and for specific physical concerns like mounting and handling noise.
  • -How is this measured? -Swept sine wave, point source loudspeaker, anechoic chamber-Distance is important -MD-421 roll off graph -SM-58 proximity effect graph -Sometimes you will see measurements that represent on-axis and off-axis response (FIND SUPER-CARDIOID EXAMPLE), but often, manufacturers presume there is relative symmetry around the "on-axis" point. This is generally true for end address, but not necessarily for side address microphones!!
  • -How is this measured? -Swept sine wave, point source loudspeaker, anechoic chamber-Distance is important -MD-421 roll off graph -SM-58 proximity effect graph -Sometimes you will see measurements that represent on-axis and off-axis response (FIND SUPER-CARDIOID EXAMPLE), but often, manufacturers presume there is relative symmetry around the "on-axis" point. This is generally true for end address, but not necessarily for side address microphones!!
  • -How is this measured? -Swept sine wave, point source loudspeaker, anechoic chamber-Distance is important -SM-58 proximity effect graph -Sometimes you will see measurements that represent on-axis and off-axis response (FIND SUPER-CARDIOID EXAMPLE), but often, manufacturers presume there is relative symmetry around the "on-axis" point. This is generally true for end address, but not necessarily for side address microphones!!
  • -How is this measured? -1 khz tone, measured at 1 Pascal of pressure, from a point-source loudspeaker in an anechoic chamber, with an impedance that should be specified!! (generally, consoles and micpres should have an impedance of >1k ohms - so it's standard to measure at 1k ohms). The "variable-impeadance" craze currently sweeping the audio industry (cloud, vipre, etc.) Generally, all modern microphones are designed to be "low-impeadance" to be complemented by a "high-impeadance" preamp input, but some of the older dynamic and ribbon microphones were actually high-impeadance, meaning they will not match well with modern mic pres. This should just be standardized and then we'd only need these impedance matching devices for vintage microphones!!
  • -Equivalent Self-noise -Important because if you are trying to pickup a quiet source, and you are using a lot of preamp gain, you don't want to boost the microphones inherent noise, you want to boost the signal picked up by the microphone!! -However, most preamps will present noise before the microphone does -The Hardy & Millennia won't!-We don't need to look at measurements, because they're simple decibel ratings and there are some general rules: -Tubes will have the most noise (SHOW) -Condensors will have some noise -Dynamics and ribbons will have the least -But these have lower output sensitivities so the preamp would need to be boosted more!!
  • -THD -this would generally be measured using the point source, anechoic technique, but it's almost impossible to find a speaker that won't distort at 130-140 dB, so they use some specialized tools to test this -different tolerances between manufacturers-Max SPL -Related to THD, this is a measurement of when the electronics begin to distort NOT WHEN THE DIAPHRAGM BEGINS TO SUSTAIN DAMAGE!! -This measurement is often made by removing the diaphragm from the equation all together, and pumping 1kHZ through the electronics at a similar voltage to what the diaphragm might put out. WE CAN ONLY HOPE THE MANUFACTURER HAS DESIGNED A DIAPHRAGM THAT CAN WITHOLD THE SAME SPL!!! -I don't trust small manufacturers that have the capabilities to do that kind of research!!-Diaphragm construction -Ribbons - 1-3 microns, rectangular, anchored at top and bottom, floating between a magnet -Condensors - 2-6 microns, stretched across a circular charged backplate with a small gap in between. -Dynamics - Robust diaphragm, attached to a coil spring suspended around a magnet -Although difficult to measure, it is believed our ear drums range between 30-120 microns thick at different points. They are also protected by fluid in the middle ear. DON'T PUT A CONDENSOR OR RIBBON ANYWHERE YOU WOULDN'T PUT YOUR EAR FOR AN EXTENDED PERIOD OF TIME
  • -DIAPHRAGM EXAMPLES -Sound = AC -when all these things are measured, they are using sine waves, the smoothest, prettiest AC available -real world signals don't necessarily look like that! -Air = DC -if you plug DC into a speaker, what happens? -if you blow air into a diaphragm, what happens? -on condensers and dynamics, the backplate charge or magnetism will help it spring back, but it's entirely possible that you can over exert the diaphragm, stretching it, and making it less responsive over timeOF TIME
  • -DIAPHRAGM EXAMPLES -Sound = AC -when all these things are measured, they are using sine waves, the smoothest, prettiest AC available -real world signals don't necessarily look like that! -Air = DC -if you plug DC into a speaker, what happens? -if you blow air into a diaphragm, what happens? -on condensers and dynamics, the backplate charge or magnetism will help it spring back, but it's entirely possible that you can over exert the diaphragm, stretching it, and making it less responsive over timeOF TIME
  • Physical aesthetics certainly play a role in our perception of a microphone. People like microphones that look good, feel good, and have a good vibe. (FISHER PRICE VS. 414) I would argue that many manufacturers spend more time and marketing on these physical aesthetics than they do on the actual technical meat and potatoes.Our subjective perception of the timbral qualities of a microphone can depend greatly on how it is placed in relation to the sound source, what room you’re working in, what electrical filters you engage (HPF most common, but some have mid-range cut filters, etc.), or Acoustic modification devices or “Acoustic Pressure Equalizers” you use, the signal chain, how carefully all the elements in the signal chain are calibrated and perhaps most of all, the performance. If the something about the performance bothers us, our mind can quickly jump to “I DON’T LIKE THAT MICROPHONE!!!”. Have you ever seen a band you really like live or on a video and gone to every effort to figure out what microphones and other gear they’re using? We all do that – but the great performance that those artists are presenting certainly colors our perception of those technical devices, and the same would go for a poor performance.And finally the context in which that performance is presented to us. A microphone sounds A LOT different when you listen to it soloed or with an instrument, and when you listen to it with and without processing.So we can look at pictures of microphones all day and many of us do, but to truly dig into the timbral details of a number of different microphones, we have to set up carefully controlled experiments and listen like crazy.
  • Physical aesthetics certainly play a role in our perception of a microphone. People like microphones that look good, feel good, and have a good vibe. (FISHER PRICE VS. 414) I would argue that many manufacturers spend more time and marketing on these physical aesthetics than they do on the actual technical meat and potatoes.Our subjective perception of the timbral qualities of a microphone can depend greatly on how it is placed in relation to the sound source, what room you’re working in, what electrical filters you engage (HPF most common, but some have mid-range cut filters, etc.), or Acoustic modification devices or “Acoustic Pressure Equalizers” you use, the signal chain, how carefully all the elements in the signal chain are calibrated and perhaps most of all, the performance. If the something about the performance bothers us, our mind can quickly jump to “I DON’T LIKE THAT MICROPHONE!!!”. Have you ever seen a band you really like live or on a video and gone to every effort to figure out what microphones and other gear they’re using? We all do that – but the great performance that those artists are presenting certainly colors our perception of those technical devices, and the same would go for a poor performance.And finally the context in which that performance is presented to us. A microphone sounds A LOT different when you listen to it soloed or with an instrument, and when you listen to it with and without processing.So we can look at pictures of microphones all day and many of us do, but to truly dig into the timbral details of a number of different microphones, we have to set up carefully controlled experiments and listen like crazy.
  • I would argue that the performance has more of an effect on our judgement than the placement and signal path, so that’s what we aimed to eliminate in our resource for online microphone comparison.
  • I would argue that the performance has more of an effect on our judgement than the placement and signal path, so that’s what we aimed to eliminate in our resource for online microphone comparison.
  • I would argue that the performance has more of an effect on our judgement than the placement and signal path, so that’s what we aimed to eliminate in our resource for online microphone comparison.
  • I would argue that the performance has more of an effect on our judgement than the placement and signal path, so that’s what we aimed to eliminate in our resource for online microphone comparison.
  • I would argue that the performance has more of an effect on our judgement than the placement and signal path, so that’s what we aimed to eliminate in our resource for online microphone comparison.
  • I would argue that the performance has more of an effect on our judgement than the placement and signal path, so that’s what we aimed to eliminate in our resource for online microphone comparison.
  • I would argue that the performance has more of an effect on our judgement than the placement and signal path, so that’s what we aimed to eliminate in our resource for online microphone comparison.
  • I would argue that the performance has more of an effect on our judgement than the placement and signal path, so that’s what we aimed to eliminate in our resource for online microphone comparison.
  • I would argue that the performance has more of an effect on our judgement than the placement and signal path, so that’s what we aimed to eliminate in our resource for online microphone comparison.
  • I would argue that the performance has more of an effect on our judgement than the placement and signal path, so that’s what we aimed to eliminate in our resource for online microphone comparison.
  • -use it to help plan your sessions -not just for vocals! -setup your own tests using this array configuration, and ideally with careful calibration to ensure your judging the microphones fairly-ear training -can you honestly hear a difference? -listen both to the timbal differences, and the noise floor-blind test each other
  • -use it to help plan your sessions -not just for vocals! -setup your own tests using this array configuration, and ideally with careful calibration to ensure your judging the microphones fairly-ear training -can you honestly hear a difference? -listen both to the timbal differences, and the noise floor-blind test each other
  • -use it to help plan your sessions -not just for vocals! -setup your own tests using this array configuration, and ideally with careful calibration to ensure your judging the microphones fairly-ear training -can you honestly hear a difference? -listen both to the timbal differences, and the noise floor-blind test each other

Transcript

  • 1. Subjective Comparison of Vocal Microphones Evaluating the microphone, not the performance http://www.bradfordswanson.com
  • 2. SUMMARY Microphones are delineated by their: • Directional characteristics • Physical and Electrical construction • Intended purpose • Performance Specifications • Subjective qualities • Cost http://www.bradfordswanson.com
  • 3. MICROPHONES–DIRECTIONALCHARACTERISTICS DELINEATION OF MICROPHONE TECHNOLOGY DIRECTIONAL CHARECTERISTICS http://www.bradfordswanson.com Source: www.bandwagonmedia.com Source: www.sennheiser.com - E602s specifications
  • 4. MICROPHONES–CONSTRUCTION DELINEATION OF MICROPHONE TECHNOLOGY PHYSICAL & ELECTRICAL CONSTRUCTION Condensor http://www.bradfordswanson.com Ribbon Dynamic Large Diaphragm Small Diaphragm Grill Construction
  • 5. MICROPHONES–INTENDEDPURPOSE DELINEATION OF MICROPHONE TECHNOLOGY INTENDED PURPOSE http://www.bradfordswanson.com
  • 6. MICROPHONES–SPECIFICATIONS DELINEATION OF MICROPHONE TECHNOLOGY PERFORMANCE SPECIFICATIONS http://www.bradfordswanson.com • Frequency Response • Output Sensitivity • Equivalent Self-Noise • THD • “Max” SPL
  • 7. MICROPHONES–OBJECTIVEQUALITIES NAVIGATING MICROPHONE SPECIFICATIONS FREQUENCY RESPONSE http://www.bradfordswanson.com Source: www.sennheiserusa.com Sennheiser MD-421 Frequency response -dotted lines represent roll-of between “M” and “S”
  • 8. MICROPHONES–CONSTRUCTION&TECHNIQUE NAVIGATING MICROPHONE SPECIFICATIONS FREQUENCY RESPONSE http://www.bradfordswanson.com Source: www.shurenotes.com Beta 58A Frequency response -dotted lines represent different distances -proximity effect compensation is built in!
  • 9. MICROPHONES–CONSTRUCTION&TECHNIQUE NAVIGATING MICROPHONE SPECIFICATIONS OUTPUT SENSITIVITY http://www.bradfordswanson.com Source: Earle, Pg. 110 In practice: -Note microphones sensitivity specs when considering placement -These sensitivity measurements change with impedance! Normal Sensitivity Ranges by Use Close-in, Handheld 2-8 mV/Pa Normal Studio Use 7-20 mV/Pa Distant Pickup 10-50 mV/Pa Output Sensitivity of Common Microphones MD421 2 mV/Pa AT-4060 19.8 mV/Pa DPA/B & K 4006 32 mV/Pa Source: Product Specifications
  • 10. MICROPHONES–CONSTRUCTION&TECHNIQUE NAVIGATING MICROPHONE SPECIFICATIONS EQUIVALENT SELF-NOISE http://www.bradfordswanson.com In practice: -Do you want to boost signal, or noise? -Preamps often have more noise than the microphone -Millennias & Hardys Don’t! Self-Noise of Common Microphones AT-4060 19 dB/A DPA/B & K 4006 15 dB/A Shure KSM-141 14 dB/A TLM-103 7 dB/A Ribbons & Dynamics Not usually specified Source: Product Specifications
  • 11. MICROPHONES–CONSTRUCTION&TECHNIQUE NAVIGATING MICROPHONE SPECIFICATIONS THD (Total Harmonic Distortion) & “Max SPL” http://www.bradfordswanson.com In practice: -Measures the point at which the ELECTRONICS distort NOT THE DIAPHRAGM Diaphragm Thickness of Common Microphones Ribbons 1-3 Microns Condensors 2-6 Microns Tympanic Membrane 30-120 Microns Dynamics >200 Microns Source: Product Specifications, http://audilab.bme.mcgill.ca/AudiLab/ear.html
  • 12. MICROPHONES–CONSTRUCTION&TECHNIQUE NAVIGATING MICROPHONE SPECIFICATIONS AIR & MICROPHONES http://www.bradfordswanson.com In practice: -Sound = AC -Air = DC Common sources of “direct” air columns Kick Drum Speaker Cones at High SPL Plosives Moving microphones Wind (Natural & HVAC) Escaping Air Column Instruments
  • 13. MICROPHONES–CONSTRUCTION&TECHNIQUE NAVIGATING MICROPHONE SPECIFICATIONS TRANSIENT RESPONSE http://www.bradfordswanson.com -Response of a system to a change in equilibrium -More sensitivity/lighter diaphragm = better transient response -Compromised/Stretched diaphragms = worse transient response
  • 14. MICROPHONES–SPECIFICATIONS DELINEATION OF MICROPHONE TECHNOLOGY SUBJECTIVE QUALITIES http://www.bradfordswanson.com Physical Aesthetics Timbral Aesthetics
  • 15. MICROPHONES–SPECIFICATIONS DELINEATION OF MICROPHONE TECHNOLOGY VARIABLES IN SUBJECTIVE TIMBRAL COMPARISON http://www.bradfordswanson.com • Placement/Technique • Room • Filters • Signal Chain • Calibration • The Performance • Context • Post-Processing
  • 16. MICROPHONES–RESOURCESFORCOMPARISON RESOURCES FOR MICROPHONE COMPARISON 3D Audio Inc. – Comparison CDs http://www.bradfordswanson.com Male and Female vocalists at 49 microphones Individual Performances at each microphone Same place in the same room Consistent signal chain and calibration Presented unprocessed and isolated Includes “blind test” opportunity $25 – available at 3daudioinc.com
  • 17. MICROPHONES–RESOURCESFORCOMPARISON RESOURCES FOR MICROPHONE COMPARISON RØDE Soundbooth – Website & App http://www.bradfordswanson.com Full band recording illustrating their products Individual Performances at each microphone Presented with an interactive mixer function Available for download as a 24bit/44.1kHz ProTools session Many samples (but not mixer function) available as a free iPhone/iPod/iPad app Available at rodemic.com/soundboothstudio
  • 18. MICROPHONES–RESOURCESFORCOMPARISON RESOURCES FOR MICROPHONE COMPARISON Shure – Mic Listening Lab http://www.bradfordswanson.com Samples across much of their product line and numerous different sources Individual Performances at each microphone Presented unprocessed and isolated Includes technical details on each mic “My Favorites” Function Available at shure.com/americas/support/tools/mic-listening-lab
  • 19. MICROPHONES–RESOURCESFORCOMPARISON RESOURCES FOR MICROPHONE COMPARISON Audio-Technica – Listening Post Website http://www.bradfordswanson.com Samples across much of their product line and numerous different sources Individual Performances at each microphone Presented unprocessed and isolated Samples are available for download as a 16bit/44.1kHz WAV files Available at eu.audio-technica.com/en/support/listen/
  • 20. MICROPHONES–RESOURCESFORCOMPARISON RESOURCES FOR MICROPHONE COMPARISON http://www.bradfordswanson.com USING UNIQUE PERFORMANCES FOR SUBJECTIVE COMPARISON pros Optimal placement Consistent signal path cons Slight differences in performance Multiple performances can become taxing and time-consuming
  • 21. MICROPHONES–RESOURCESFORCOMPARISON GOALS GUIDING OUR RESEARCH http://www.bradfordswanson.com Procedure • Single performances at groupings of 3-4 closely related microphones • Similar performances at twelve of these groups • Capsules as close together as possible • Multiple vocalists and contrasting material • A consistent control • Similar signal path • Mindful calibration and presentation
  • 22. MICROPHONES–RESOURCESFORCOMPARISON GOALS GUIDING OUR RESEARCH http://www.bradfordswanson.com Calibration • 400 hz tone @ 85 dB SPL • Preamp input levels carefully metered and matched • Performance samples peak normalized Presentation • Intuitive and efficient website • Compatible with multiple browsers & mobile devices • HTML 5 players with16 bit/44.1kHz samples • Easy and fast switching between samples • Voiceover examples presented unprocessed • Musical examples presented in context & isolation
  • 23. MICROPHONES–RESOURCESFORCOMPARISON EXECUTING OUR RESEARCH http://www.bradfordswanson.com Initial 20-hour Session
  • 24. MICROPHONES–RESOURCESFORCOMPARISON EXECUTING OUR RESEARCH http://www.bradfordswanson.com Experiments with different array configurations
  • 25. MICROPHONES–RESOURCESFORCOMPARISON EXECUTING OUR RESEARCH http://www.bradfordswanson.com Three-day lockout session • Twelve stations of 3-4 microphones each (plus control) • Four performers of contrasting styles • Two Male, Two Female • Two Vocalists, Two Voiceover Artists • Each performer allotted a 2-3 hour session • Each performer presenting 2-3 takes at each station • Accompanying instruments for contextual examples • “cupped hands” test • Carefully organized studio and control room • Secure performance agreements from vocal artists
  • 26. MICROPHONES–RESOURCESFORCOMPARISON EXECUTING OUR RESEARCH http://www.bradfordswanson.com Three-day lockout session
  • 27. MICROPHONES–RESOURCESFORCOMPARISON EXECUTING OUR RESEARCH http://www.bradfordswanson.com Post Production • Assess performances and export samples of the best takes • Make note of performance anomalies • Mix stereo musical examples (with processing) for contextual examples
  • 28. MICROPHONES–RESOURCESFORCOMPARISON EXECUTING OUR RESEARCH http://www.bradfordswanson.com Preparing for Presentation • Document procedure and develop web content • Collaborate on web design, coding and implementation • Gather peer feedback and continual refine website • Develop engineering brief for conference submission • Develop poster for AES conference • Develop powerpoint presentation for UML AES • Present poster
  • 29. MICROPHONES–RESOURCESFORCOMPARISON USING OUR RESEARCH http://www.bradfordswanson.com
  • 30. MICROPHONES–RESOURCESFORCOMPARISON USING OUR RESEARCH http://www.bradfordswanson.com • Session Planning • Ear Training • Compiling your own comparisons • Blind Testing Drinking Games But keep in mind: • Proximity effect • Sensitivity, Self-Noise, THD & max SPL • Construction • Practical Use
  • 31. MICROPHONES–RESOURCESFORCOMPARISON ACKNOWLEDGEMENTS http://www.bradfordswanson.com RESEARCH TEAM Nick Foudi Matthew Wall ASSISTANT ENGINEERS Marissa Broe Daniel Desmond Jamie Tagg FACULTY ADVISOR Professor Alexander U. Case WEB DEVELOPMENT Lara Swanson VOCALISTS Steve Aliperta Jana Deren VOICEOVER ARTISTS Bob Kuhn Penelope Morel SPECIAL THANKS Professors William Carman and Paul Angelli; Drs. William Moylan, Alex Ruthmann, John Shirley, and Alan Williams; Jeremy Houle, Michael Gates, Jason York, and Gergana Antova
  • 32. MICROPHONES–RESOURCESFORCOMPARISON FURTHER READING http://www.bradfordswanson.com Eargle, J. (2004). The Microphone Book (2nd Edition). Burlington, MA: Focal Press. Olson, H. (1955). Musical Engineering (2nd Edition). New York, NY: McGraw-Hill. Woszczyk, W. (1989, March). Diffraction Effects in High Quality Studio Microphones. AES Convention Paper #2792
  • 33. www.bradfordswanson.com/mic