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/
4. MICROPHONES–CONSTRUCTION
DELINEATION OF MICROPHONE TECHNOLOGY
PHYSICAL & ELECTRICAL CONSTRUCTION
Condensor
http://www.bradfordswanson.com
Ribbon Dynamic
Large
Diaphragm
Small
Diaphragm
Grill Construction
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
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
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
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
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
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