Advanced Location Sound Recording Workshop

1 – Title slide

SLIDES and NOTES: Location Sound Recording Workshop (Using Advanced Audio Kit)

ARTD 3480 Video: Sound+Image, Fall 2025

Using the Advanced Audio Kit, 2025-09-16 (Rev 3)

These slides are designed to accompany a hands-on workshop introducing the Advanced Audio Kits available from the CAMD Media Center and an opportunity to record sounds under various scenarios using the kit and then listen to the results and reflect on the experience. This work is in “perpetual beta,” and your suggestions for improvement would be appreciated! Please refer to the last slide for copyright notice and acknowledgments.

CONTENTS: Sound Devices MixPre-3 II; Audio-Technica BP4029 MS Stereo microphone; Rycote Pistol Grip and Softie; K-Tek Avalon Stereo Boom Pole; Electro-Voice RE50 microphone; Tram TR-50 microphone with TR79 Power Supply; Microphone cables; Microphone pick-up patterns; Microphone frequency response curves; Sony MDR-7506 Headphones; Three MixPre-3 II configurations we’ll use in this course; User interface and Navigating Menus in Basic Mode; Powering the recorder with a USB power bank; Operation in Basic Mode; Channel Configuration in Basic Mode; Setting recording levels; Recording; Playing back files; Copy media to your computer after recording; Configure the recorder with custom settings; MixPre-3 II Block Diagram; “STEREO-MIC” configuration; Saving Presets to the SD Card; Configuring bit-depth and sampling rate; 32-bit float audio in post-production; Summary of our three custom presets (STEREO-MIC, ONE-MONO-MIC, TWO-MONO-MICS); Resources for further study

2 – Advanced Audio Kit

Students in some classes can check out the Advanced Audio Kit. Check with Media Center staff regarding availability.

3 – Advanced Audio Kit Inventory

The Advanced Audio Kit differs from the Location Audio Kit in three significant ways:

designed around the Sound Devices MixPre-3 II, a professional recorder that can be configured for a wide range of recording scenarios;

includes the Audio-Technica BP4029 MS stereo short shotgun condenser microphone instead of the Sennheiser MKE600 mono short shotgun condenser microphone to enable stereo recording; and

The kit comes with a wired stereo boom pole (the wired mono boom pole in the Location Audio Kit isd a separate check-out item).

4 – Sound Devices MixPre-3 II

The Sound Devices MixPre-3 II is a professional field mixer/recorder that is user-friendly once you understand how it works. The out-of-the-box settings are not ideal for using for location sound recording, therefore, we recommend using one of the three configurations covered in the Location Sound Recording workshop before going out to record.

Professionals love the flexibility of the MixPre series, but if you are just starting out, you can use basic mode to keep things as simple as possible.

The Sound Devices MixPre II can be used as a USB audio interface; supports up to 96 kHz sample rate at bit depths of 16, 24, 32-bit integer or 32-bit float. The 32-bit float USB audio path makes it possible to record into a DAW above 0 dBFS without clipping.

You can use this kit to record field audio, sound effects, audio for video, podcasts, voice-overs, music, and it can also be used as a USB interface to capture audio directly into Adobe Premiere Pro, Adobe Audition, or DaVinci Resolve.

5 – Sound Devices MixPre-3 II

The MixPre-2 II is capable of recording up to 32-bit float bit depth and up to a 192 kHz sample rate. In Basic Mode the Sample Rate and Bit Depth is fixed at 48/24. Sample Rates supported: 44.1 kHz, 47.952 kHz, 48 kHz, 48.048 kHz, 96 kHz, 192 kHz. Bit Depths supported: 16-bit, 24-bit, and 32-bit Float. When used as a 2x2 USB Audio Interface it supports up to 96 kHz sample rate at bit depths of 16, 24, 32-bit integer or 32-bit float.

6 – Sound Devices MixPre-3 II

The following are available in the Advanced Audio Kit:

USB Power Bank via USB-C cable

Included MX-PSU AC wall adapter to USB-C power supply.

Four AA batteries installed in the included MX-4AA Battery Sled (consider this only as back-up power when using with USB Power Bank.

USB C cable connected to a computer (not all computers support the high-current requirements of the MixPre).

Refer to the MixPre series manual and the Sound Devices support pages for a complete listing of power options.

The recommended powering configuration is the USB power bank as the primary source of power with the 4 AA battery sled as backup. MixPre-3 II supports power switchover and priority — To preserve battery power, USB-C power sources take priority over batteries if both are connected with one exception - if the USB-C power source does not meet the full power requirements of the MixPre II, you can choose to power from battery or continue to power from USB-C. An underpowered MixPre II will be able to use two of the three or four channels with 48 V phantom mics. Other channels can still be used with dynamic mics and line level, Aux, or USB sources. In a low power state, the MixPre II automatically: 1. Dims LCD and LED Brightness. 2. Disables USB-A port. 3. Disables HDMI TC port. For protection against accidental loss of power, the MixPre II incorporates circuitry to automatically switch over from USB-C to batteries.

7 – Sound Devices MixPre-3 II

The MixPre sports ultra low-noise preamps which sets it apart from the Zoom recorders in the Location Audio Kit. The MixPre II is highly customizable to your needs. The device records internally to a compatible SD card and can auto-copy after each recording to a USB thumb drive. The recorder allows you to adjust limiters, bit depth, sample rates, gain, pan, low-cut, phase inversion and phantom power to your liking. A high-precision internal timecode generator allows you to jam sync with other devices, serve as a master clock. The MixPre can also trigger a camera or feed timecode into a camera. For an in-depth list of settings and options not covered in this workshop, refer to the MixPre-3 II manual (there’s a link to the PDF in the Resources section).

8 – Why should we record SFX and ambiences in stereo?

Stereo recording is more immersive because it mimics the way we naturally hear sound in the real world.

Spatial Perception: We use both ears to hear sounds from different directions. Stereo recording captures sound using two channels (left and right), which allows us to perceive directionality—whether a sound is coming from the left, right, or center. This spatial separation creates a more natural sound field and and thus we feel more present in the storyworld.

Depth and Width: Stereo recording include audio cues enabling the perception of depth (how close or far away a sound is) and width (how wide the sound stage is). This gives the listener a sense of space and positioning of sound sources.

Sound Localization: Our auditory system detects slight differences in timing and volume (known as interaural time and level differences) to localize sound. Stereo recording captures these variations, enabling us to pinpoint where sounds are coming from. This enhances the sense of being surrounded by sound, especially when listening through headphones or a good speaker setup.

Echo and Reverb: In a stereo recording, reflections of sound (echoes or reverb) can be captured and played back realistically (or simulated in postproduction) to preserve the acoustic characteristics of of the original reciording or create the sense of being in a real environment that was fabricted in postproduction to increase the sensation of presence.

Enhanced Emotional Impact: By providing a more realistic and nunced soundscape, stereo recordings have the potential to evoke stronger emotional responses from us.

Cues for sound localization illustration from: Grothe, Benedikt, et al. “Mechanisms of Sound Localization in Mammals.” Physiological Reviews, vol. 90, no. 3, 2010, pp. 983–1012, https://doi.org/10.1152/physrev.00026.2009.

9 – What is stereo recording?

Stereo recording is a technique used to capture audio with two or more microphones, with the goal of reproducing the spatial characteristics of sound.

There are several common techniques for stereo recording:

XY Technique: Two directional microphones are placed close together, angled between 90° and 135° to each other to capture sound from different directions. This method avoids phase problems (timing differences) between the two channels. The stereo effect is achieved through differences in sound pressure level between two microphones. Due to the lack of differences in time-of-arrival/phase ambiguities, the sonic characteristic of X-Y recordings has less sense of space and depth when compared to recordings employing an A-B setup. When two figure-eight microphones are used, facing ±45° with respect to the sound source, the X-Y setup is called a Blumlein Pair and it produces a realistic sonic image.

AB Technique: Two omnidirectional microphones are placed in parallel, often 60 cm (24 in) apart, to capture sound. This technique is great for recording the ambience of a space, as it mimics the distance between human ears, capturing time-of-arrival stereo information as well as some level (amplitude) difference information – especially if employed in close proximity to the sound source. At a distance of 60 cm (24 in) the time delay (time-of-arrival difference) for a signal reaching the first microphone and then the other one from the side is approximately 1.5 ms (1 to 2 ms). If you increase the distance between the microphones, you effectively decrease the pickup angle. This technique can produce phase issues when the stereo signal is mixed to mono.

Mid-Side (MS) Technique: One directional microphone (mid) faces the sound source, while the second microphone is bidirectional (side) captures the sound from both sides. This technique allows for flexibility in adjusting the stereo width after recording. The left and right channels are produced through a simple matrix: Left = Mid + Side; Right = Mid − Side (the polarity-reversed side signal). This configuration produces a completely mono-compatible signal and, if the Mid and Side signals are recorded (rather than the matrixed Left and Right), the stereo width can easily be manipulated in postproduction, making MS particularly useful for for film/video projects.

Binaural Recording: Uses two microphones placed inside a dummy head or in-ear microphones to closely mimic how humans perceive sound. This can create a realistic 3D sound experience, especially when listened to with headphones. Pprovides accurate auditory spatiality that is similar listening from the same place as the dummy head. Because of the inconvenience of wearing headphones, true binaural recordings have remained curiosities.

Sources: (1) Studying Sound: A Theory and Practice of Sound Design by Karen Collins, MIT Press, 2020, https://amzn.to/4dy1Pgr; (2) “Stereophonic sound,” Wikipedia, https://en.wikipedia.org/wiki/Stereophonic_sound

10 – What is MS stereo recording?

Mid-Side (MS) is a stereo recording technique that uses two microphone (or a special microphone with two capsules) to create a stereo signal: (1) The Mid microphone (or capsule) typically has a cardioid or hypercardioid pick-up pattern and it is directed at the center of the sound field; (2) The Side microphone (or capsule) has a figure-8 pick up pattern and is is positioned as close as possible to and 90 degrees off-axis from the Mid microphone (or capsule). The Mid acts as the center channel, while the Side microphone adds or subtracts information from either side to create ambience and directionality. The Side channel’s loudness determines the stereo width, with louder Side channels producing wider sounds.

11 – What is MS stereo recording?

Stereo MS recordings have several advantages: 1. The conversion between MS and Left-Right stereo is reversible and lossless; 2. MS is the only stereo system where the width can be adjusted from hard mono to extreme diffuse out-of-phase sound after recording; 3. MS is coincident and mono compatible (the S-signal cancels out when summed to mono so there are no phase issues); 4. With MS, one microphone points directly in the main direction, unlike other systems in which the main direction is covered by the microphones off-axis.

The MS to LR conversion process:

L = M + S

R = M - S

The LR to MS conversion process:

M = (L + R) / 2

S = (L - R) / 2

For the technical details, see:

Hugh Robjohns, “How does Mid-Sides encoding/decoding actually work,”Sound on Sound, April, 2017, https://www.soundonsound.com/sound-advice/q-how-does-mid-sides-recording-actually-work

Eddy Bøgh Brixen, “Setups for stereo: MS,”DPA Microphones, https://www.dpamicrophones.com/mic-university/audio-production/stereo-recording-techniques-and-setups/

Studying Sound: A Theory and Practice of Sound Design by Karen Collins, MIT Press, 2020, https://amzn.to/4dy1Pgr

12 – Audio-Technica BP4029 MS Stereo microphone

The Audio-Technica BP4029 MS Stereo Short Shotgun Condenser Microphone is a versatile microphone for location sound recording under a variety of conditions. Make sure the “UP” indicator is properly oriented when recording Stereo or MS.

Select MS for mono (M) recording or M-S Stereo recording.

Select LR-W for wide field stereo recording or LR-N for narrow field stereo recording.

Both channels require +48V Phantom Power.

The microphone has a built-in low cut filter.

You need an XLR-5F (Stereo) to 2 XLR-3M adapter (1/Left and 2/Right) to connect the microphone or a stereo mic cable to the recorder that only has mono inputs.

Cable Color Convention:

Ch. 1 / Left — White, Gray, White, or Blue

Ch. 2 / Right — Red

MS means it has two capsules: a middle (M) capsule with a line-cardioid pick-up pattern and a second side (S) capsule with a figure-of-eight pick-up pattern. Normally the discrete M and S channels are decoded into stereo either by the microphone or the recorder or later in post-production. The actual model name is BP4029 but we’ll call it the 4029 or stereo shotgun for short! Make sure the “UP” indicator is properly oriented when recording Stereo or MS. Select MS for mono (M) recording or M-S Stereo recording. Select LR-W for wide field stereo recording or LR-N for narrow field stereo recording). Both channels require +48V Phantom Power. The microphone has a built-in low cut filter. MS means it has two capsules: a middle (M) capsule with a line-cardioid pick-up pattern and a second side (S) capsule with a figure-of-eight pick-up pattern. Normally the discrete M and S channels are decoded into stereo either by the microphone or the recorder or later in post-production.

13 – Audio-Technica BP4029 MS Stereo microphone

The following usage scenarios are possible:

MS MICROPHONE PAIR — When the microphone is set to MS mode, it can be used for MS stereo recording with discrete middle and side signals in channels 1 and 2, respectively, in postproduction or during recording (the MixPre is capable of doing this) the independent M and S signals can be converted to stereo using a plug-in like Voxengo MSED.

MONO SHORT SHOTGUN — You can use the M channel and ignore the S channel. For mono recording set the microphone to MS mode, the mid capsule is connected to channel 1 and ignore channel 2. This can be done with an XLR-5F to XLR-3M adapter cable if working with a mono cable or boom pole or simply ignoring channel 2 when working with stereo cables (as with the Advanced Audio Kit that comes with a stereo cable and a stereo boom pole). On the MixPre set the pan of Channel 1 to C and ignore Channel 2.

STEREO MICROPHONE WITH WIDE STEREO FIELD — The microphone has a built in MS stereo decoder, select LR-W for wide field stereo recording, the microphone will output stereo.

STEREO MICROPHONE WITH NARROW STEREO FIELD — The microphone has a built in MS stereo decoder, select LR-N for wide field stereo recording, the microphone will output stereo.

I use my BP4029 in all four of these configurations on a regular basis. To use it as a mono short shotgun, I keep an XLR5-F to XLR3-M adapter cable (not included in the Advanced Audio Kit) handy since the microphone has a XLR5-M connector on the end and sometimes I need to go into a mono microphone cable. But most of the time I use it on the end of my stereo boom pole. An additional use case is cinéma-vérité shooting with the microphone mounted on the camera when I’m not concerned about stereo, so I set the microphone to MS mode which provides the M and S as discrete independent channels recorded to channel 1 and 2 respectively with the microphone mounted on the camera. Thus channel 1 provides me with the dialogue in front of the camera and channel 2 provides me with whatever is happening to the right or left of the camera, sometimes it’s my dialogue and other times it might be someone talking to the subject in front of the camera. This second channel gives me a lot more flexibility in postproduction. Thus the BP4029 provides a versatile microphone we can use in one of five ways! And I can always transform the discrete M-S to stereo and visa-versa with no quality loss in post if needed using the Voswego MSED plug-in (installed in Shillman Media Studio workstations). A super versatile microphone!

14 – Rycote Pistol Grip and Softie

Pistol grip can be used for hand-holding the mic or mounting on the end of a boom pole; softie windjammer reduces the effect of wind noise.

The “Mic-Tail” fits in the Pistol Grip and serve two purposes: reducing transmission of cable handling noise to the mic and makes it easy to switch between hand-held use and mounting on the end of the boom pole use, the “Mic-Tail” connector should always stay in the grip, which, again, reduces transmission of cable handling noise to the mic, you don’t want to mic cable directly connected to the microphone, which is suspended in a shock mount.

15 – K-Tek Avalon Stereo Boom Pole

Attach the Pistol Grip to the end of the boom pole; connect the XLR-5F to the end of the “Mic Tail” connector in the handle of the pistol grip; connect the boom pole to the MixPre using the coiled cable (with the XLR-5F to Dual XLR-3M adapter connected between the MixPre inputs and the coiled boom cable). IMPORTANT — Be careful to avoid rotating the sections of the boom pole as this can lead to kinks in the internal coiled cable. If you experience resistance collapsing the pole, DO NOT FORCE THE SECTION TO COLLAPSE, instead, gently turn the loose section clockwise and counter-clockwise to see if that helps with your attempt to collapse the section. If it does not, seek help from your instructor or Media Center staff; a kink may have developed in the coiled cable and the boom pole will require a repair procedure.

16 – Electro-Voice RE50 microphone

The Electro-Voice RE50 microphone is a broadcast production classic. This omnidirectional dynamic microphone is designed for on-camera reporting; also good for close proximity voice-over recording and recording high SPL SFX due to low sensitivity. The actual model name is RE50N/D-B but we’ll call it the RE50 for short!

When wrapping: Make sure all accessories are returned to the handheld microphone pouch!

17 – Tram TR-50 microphone with TR79 Power Supply

The TR-50 Microphone with TR79 Power Supply is widely used in broadcast, documentary, and film production applicaitons. This omnidirectional condenser lavaliere is ideal for interviews, cinéma-vérité, on-camera reporting; may also be used as a plant mic. Important: Always power with +48 Phantom Power from the MixPre, do not use the battery! The only use-case for the battery is when using the mic with a mic input that does not support Phantom Power, which does not apply with this kit! Important: Always keep the mounting accessories (a.k.a. “jewelry”) in the storage case (and keep it closed) to avoid losing them! The actual model name is RE-50 but we’ll call it the Tram for short!

When wrapping:

Make sure all of the accessories (a.k.a. jewelry) are returned to the lavaliere microphone case.

Make sure battery is not installed in the TRAM (Note: you normally don’t need to use batteries with the shotgun or lavaliere in this kit since the MixPre provides phantom power, it’s also a best practice to store gear without batteries to prevent damage from battery corrosion, the TRAM case has a spot to hold the battery, and that is where it belongs (or properly recycled, you really don’t need the battery in this kit).

18 – Microphone cables

Microphone Cable Inventory (this needs to be confirmed with the Media Center):

XLR-5M to XLR-5F (Stereo) Microphone Extension Cable;

Short XLR-3M to XLR-3F Microphone Cable (handy for use with RE50 or TR50);

XLR-5M to XLR5F “Mic-Tail”;

XLR-5M to XLR-5F (Stereo) Coiled Boom Cable;

XLR-5F to 2 XLR-3M adapter (Stereo to 1/Left and 2/Right) — use this to adapt coiled boom cable to the recorder 1/2 inputs.

When wrapping: Wrap all microphone cables using the over-under technique, see tutorial video in the resources section if you are not familiar with the technique.

19 – Microphone cables

Balanced microphone cables with XLR connectors are widely used for professional audio. Balanced wiring has two conductors and one ground plus special circuitry on each end in order to reduce susceptibility to electromagnetic interference (EMI) and allows for longer cable runs. The best cables use twisted pairs for each conductor (“star-quad”) for even better EMI rejection. Consumer gear uses wiring with only one conductor and one ground and is therefore more susceptible to interference. The gold-standard for microphone cables are star-quad cables with a twisted pair for each conductor, further reducing susceptibility to EMI. For a technical explanation of how balanced lines works, see “What’s the Difference Between Balanced and Unbalanced?,” Aviom Blog, https://www.aviom.com/blog/balanced-vs-unbalanced/

20 – Microphones in the kit and typical use cases

Typical use cases of the microphones in this kit:

RE50 — hand-held, VOXPOP; voice-over; good for high SPL SFX due to low sensitivity;

worn on speaker, may also be used as a hidden mic;

boom or pistol-grip-mounted dialogue, ambience, SFX

In most cases it’s best to record ambience in stereo, use the LR-WIDE mode in the BP4029 for this. Specific sound effects may benefit from stereo recording, use the LR-WIDE or LR-NARROW mode depending on your use case. You can record stereo boom dialogue and then pull out the Mid channel in post using the MSED plug-in from Voxwego (installed in the Shillman labs) if you recorded stereo or simply configure in MS mode and ignore the S channel to record standard MONO DIALOGUE.

21 – Microphone pick-up patterns

Microphone pick-up patterns:

RE50 — omnidirectional

TR-50 — omnidirectional

BP4029 — Mid capsule: line-cardioid; Side capsule: figure-of-eight

22 – Microphone frequency response curves

Comparison of microphone frequency responses:

TR-50 — very smooth response with a high-frequency boost specifically designed to compensates for typical lavaliere placement;

RE50 — overall response not as smooth as the TR-50 or BP4029 but it does very well in voice applications;

BP4029— smooth response with some boost in the highest harmonics between 3K and 9K

23 – Sony MDR-7506 Headphones

Always monitor your recordings! Circumaural headset design helps eliminate headphone bleed in recording and improves audio monitoring by attenuating ambient sounds.

Warning: The MixPre can drive headphones at very high levels, always lower level before putting on headphones!

Important — Always return gear in the same configuration as you found it when you checked it out! Both cables and the headphones must be wrapped properly. Proper wrapping of MDR-7506: Simply fold and place headphones in the pouch and then drop the cable on top. Do not wrap the cable around the headphones, it damages the coil and the proper technique is less effort!

24 – Three configurations we’ll use in this workshop

We will configure and save three custom modes:

STEREO-MIC — for stereo recording using the BP4029 configured in LR-N or LR-W mode with a single gain control for left and right channels; no ISO channels, recorder creates a standard two channel stereo WAV file;

ONE-MONO-MIC — When recording with one mono mic, no ISO channels, recorder creates a standard two channel stereo WAV file (ch 1 and ch 2 are the same, this is called a “Dual Mono” file technically);

TWO-MONO-MICS — When recording with two discrete mono mics (e.g. recording with TR-50 on interviewer and RE50 capturing vox-pop interviews) with separate gain control for each mic, mic 1 routed to ch. 1 in the WAV file and ch. 2 routed to ch. 2 in the WAV file, no ISO tracks (simple two channel WAV file is recorded).

Presets can be saved to the SD card and copied so that they may reloaded during future recording sessions, so don’t forget to copy the SETTINGS folder when downloading media.

25 – Sound Devices MixPre-3 II

BE VERY CAREFUL AND MAKE SURE BATTERY SLED IS PROPERLY ALIGNED BEFORE PRESSING ON IN ORDER TO AVOID DAMAGING THE BATTERY CONTACTS!

MixPre-3 II Power Switchover and Priority — To preserve battery power, USB-C power sources take priority over batteries if both are connected with one exception - if the USB-C power source does not meet the full power requirements of the MixPre II, you can choose to power from battery or continue to power from USB-C. An underpowered MixPre II will be able to use two of the three or four channels with 48 V phantom mics. Other channels can still be used with dynamic mics and line level, Aux, or USB sources. In a low power state, the MixPre II automatically: 1. Dims LCD and LED Brightness. 2. Disables USB-A port. 3. Disables HDMI TC port. For protection against accidental loss of power, the MixPre II incorporates circuitry to automatically switch over from USB-C to batteries.

MixPre-3 II Power Options (not all available in the Advanced Audio Kit)

Included MX-PSU AC wall adapter to USB-C power supply.
Four AA batteries installed in the included MX-4AA Battery Sled.
Eight AA batteries installed in the optional MX-8AA Battery Sled accessory.
One or two Sony-type L-Mount batteries installed in the optional MX-LMount battery sled accessory.
USB-C to USB-C cable (included) connected to a USB-C host computer or AC wall adapter.
USB-A to USB-C cable connected to a USB-A host computer or AC wall adapter. The unit will enter a low power state and some functionality will be limited with this power option.
MX-USBY Dual USB-A to USB-C optional accessory cable connected to a USB-A host computer. Use this cable option if your computer is unable to provide adequate power with only one USB-A port.

26 – Let’s Start in Basic Mode

The MixPre II’s flexibility is enhanced by its ability to select various input types to its mixer channels. On the MixPre-3 II, channels can be sourced from XLR mic/line input, 3.5 mm Aux line or mic input, or from USB channels. On the MixPre-6 II and MixPre-10 II, channels can be sourced from XLR or TRS mic/line input, 3.5 mm Aux line or mic input, or from USB channels.

Access the channel’s input settings by pushing in the channel’s knob. There are three channel inputs on the MixPre-3 II, 6 channel inputs on the MixPre-6 II, and 10 channel inputs on the MixPre-10 II.

Channels 5 and 6 on MixPre-6 II and 9 and 10 on the MixPre-10 II are controlled in the Inputs menu. Input source, gain, pan, and lowcut are all available in this menu.

Channels use a single gain stage adjusted by the knob. Levels set at the channel knob are sent to the LR mix record channels and the LR outputs. Limiters are present on each channel and the LR mix bus and will ensure that your audio is safe from accidental clipping.

27 – Navigating Menus in Basic Mode

User interface consists of Home screen, Main Menu screen, and Channel screen views 1: File List Icon — Touch to enter the File List // 2: Current File Name — Displays the current file name. // 3: Cue Marker Icon — Touch to lay a cue marker during record or playback. Displays current cue mark point. // 4: Power Status Icon — Displays the status of the active power source. See tables opposite for further details. // 5: Menu Icon — Touch to enter the setup menu. // 6: Meter View — Battery power is critically low. Change batteries. Displays audio activity. Touch to toggle through available meter views: 1. Left and Right mix tracks. 2. Left and Right mix tracks with isolated tracks. 3. Left and Right mix tracks, USB inputs 1 and 2, and 2 camera returns (when Aux inputs are set to camera). // 7: Status Bar — Touch to toggle information displayed: 1. SD card status — card/drive activity, available recording time, file duration, elapsed time, and headphone preset. 2. USB drive status: remaining space on drive, sample rate, bit depth. 3. Sync Source (if external) — sample rate, and bit depth. 4. Date and time. While auto-copying, copy status is displayed on all status bars. Copy status will alternate with default info. // 8: Time Counter — Displays current timecode value. If timecode is Off, displays time counter of recording file.

28 – User interface

User interface consists of Home screen, Main Menu screen, and Channel screen views

File List Icon — Touch to enter the File List

Current File Name — Displays the current file name.

Cue Marker Icon — Touch to lay a cue marker during record or playback. Displays current cue mark point.

Power Status Icon — Displays the status of the active power source. See tables opposite for further details

Menu Icon — Touch to enter the setup menu

Meter View — Battery power is critically low. Change batteries. Displays audio activity. Touch to toggle through available meter views: 1. Left and Right mix tracks. 2. Left and Right mix tracks with isolated tracks. 3. Left and Right mix tracks, USB inputs 1 and 2, and 2 camera returns (when Aux inputs are set to camera).

Status Bar — Touch to toggle information displayed: 1. SD card status — card/drive activity, available recording time, file duration, elapsed time, and headphone preset. 2. USB drive status: remaining space on drive, sample rate, bit depth. 3. Sync Source (if external) — sample rate, and bit depth. 4. Date and time. While auto-copying, copy status is displayed on all status bars. Copy status will alternate with default info. // 8: Time Counter — Displays current timecode value. If timecode is Off, displays time counter of recording file.

29 – Powering the recorder with a USB power bank

Connect USB cable to USC-C Input

Enable the Power Bank (push button on the Power Bank)

Verify USB power

Always use with 4 AA batteries in the 4 AA battery sled, this is your backup power in the event the power bank is disconnected.

30 – Set the date and time

Connect USB cable to USC-C Input

Enable the Power Bank (push button on the Power Bank)

Verify USB power

Always use with 4 AA batteries in the 4 AA battery sled, this is your backup power in the event the power bank is disconnected.

31 – Formatting media

Formatting Media — Format SD Card: (1) Insert an SD card in the SD Card Slot; (2) Navigate to SD Card > Edit > Format; (3) When asked to confirm the command to format the card, touch OK. Format USB Thumbdrive: (1) Connect a USB ThumbDrive to the USB-A port; (2) Navigate to USB Drive > Edit > Format; (3) Confirm the command to format the card, and touch OK.

SD cards must be formatted by the MixPre II for reliable recording and playback. Back-up any wanted audio recordings or data on the SD card before formatting. The formatting process erases all data on the SD card. If a USB thumbdrive is inserted into the USB A port, the MixPre II automatically copies the current project’s recorded files to it. The thumbdrive must also be formatted before use. Sound Devices recommends Sound Devices branded SD cards as these have been optimized to provide the best performance. If these are not available, most reputable manufacturers’ cards (such as SanDisk or Delkin) that meet or exceed class 10 speeds are acceptable. All media will be formatted as exFAT. If any media is formatted differently, the MixPre will display a formatting reminder. The exFAT file system is not compatible with Windows XP or Mac OS X 10.6.4 and lower.

USB Auto-Copy — The MixPre II will auto-copy to a formatted USB-A thumbdrive when inserted directly into the USB-A port or when using a USB hub. Stopping a recording will automatically copy the last recorded file to the thumbdrive. While copying, the record button on the MixPre-3 II and MixPre-6 II and the ring LED on the MixPre-10 II will flash while the process is being completed. The completion rate will display as a percentage on the bottom right corner of the status bar. If a new recording is started while auto-copying is still in progress, auto-copying will still continue.

Interrupting USB Auto Copy With Power Cycle — Auto-copy can be temporarily suspended during longer copying times. During auto-copy in stop mode, pressing stop or toggling the power switch to OFF brings up the following popup: “Suspend USB auto-copy? Copying will resume when record is next pressed. OK, Cancel” If “OK” is pressed, Auto-copying is suspended and will resume copying when record is next pressed. If “Cancel” is pressed, Auto-copying will continue until complete then power down if switch is off or sit in idle if power switch is on. While the MixPre II is auto-copying, the USB Drive and SD Card menu are unavailable.

32 – Operation in Basic Mode

Record Submenu - Basic Mode

Pre-Roll Time - Pre-roll captures audio for a set amount of time before Record is pressed, ensuring important audio is never missed. Pre-roll time decreases as sample rate increases. Choose up to 10 seconds of pre-roll at 48 kHz. At 96 kHz pre-roll is limited to a maximum of five seconds, and two seconds at 192 kHz. Pre-roll is not available in record run mode or when using a record trigger.

REC Trigger - Sets record triggering from either timecode, HDMI flag or HDMI FUJIFILM flag. The default is Off.

Record Bells - Enable or disable record bell notifications. Record bells are On by default.

33 – Channel Configuration in Basic Mode

Channel Screen - BASIC MODE — On the MixPre-3 II, channels can be sourced from XLR mic/line input, 3.5 mm Aux line or mic input, or from USB channels. Access the channel’s input settings by pushing in the channel’s knob. There are three channel inputs on the MixPre-3 II. In BASIC MODE Channels use a single gain stage adjusted by the knob. Levels set at the channel knob are sent to the LR mix record channels and the LR outputs. Limiters are present on each channel and the LR mix bus and will ensure that your audio is safe from accidental clipping. // Pan — Pan the channel’s signal Left, Center or Right in the stereo LR mix and Stereo Out. // Low Cut — Turn Low Cut filter on or off. Useful for reducing unwanted low frequency in the audio of the select channel. In Basic Mode Low Cut is fixed at 80 Hz.

// Input — Select one of the available Mic, Line, Aux (available when Aux In Mode is Mic or Line) or USB inputs as the channel source. // Phantom — Turn on 48 V phantom power when using a condenser microphone in the selected channel (available when Input is Mic).

34 – Channel Configuration in Basic Mode

35 – Setting recording levels

The MixPre provides a combination of Peak and VU meter ballistics to help you set recording levels.

Audio meter ballistics is the manner in which a visual meter responds to audio signal levels. Peak-reading ballistics correspond to actual signal peaks, but do not necessarily correspond to perceived signal loudness. Peak meters have an instant attack and slow decay and are useful in digital audio workflows where signal overload can cause immediate distortion. Volume Units (VU) meter ballistics correspond closely to how the human ear perceives loudness. VU meters provide good visual indication of how loud a signal will be, but provides poor information of actual signal peaks.

The MixPre II uses a combination Peak+VU ballistics for all meters, where the perceived loudness (or VU) is simultaneously displayed as a standard bar while the peak signal is displayed as a single, independent segment above the VU.

The MixPre recorders have very quiet preamps so you are OK recording with peaks seldom going over -6 Unlike the Zoom H4n which has noisy preamps so we tend to run the signal hotter to stay above the noise floor of the Zoom H4n.

36 – Recording

Transport Controls: Record —- Press to begin recording a new file. The button illuminates red while recording is in underway. In Stop mode the record button flashes red while auto-copying to a USB thumb drive. // Stop — While recording, press once to stop recording. While in playback, press once to stop playback. While in standby, press and hold to display next name. While in Standby and auto-copying is in progress, press Stop to optionally suspend auto-copying. // Play/Pause —

Press to begin playback of the last file recorded or file currently loaded. The button illuminates green during playback. While in playback, press once to pause, and press again to resume playback. Whenever playback is paused, the button and the current file name will flash green. // Scrub — While playing or paused, press and hold the headphone encoder to enter Scrub mode. Then rotate clockwise for fast forward or counter-clockwise for rewind at speeds of 0x, 1/8x, 1/4x, 1/2x, 1x, 2x, 4x, 8x and 16x. The audio is heard in Scrub mode up to 2x speed. Scrubbing at speeds < 1x are not available with 32-bit float.

37 – Playing back files: File List

File List - Basic Mode To Access The File List

Touch the filename at the top of the Home screen.
Scroll through the chronological list of all files in an active project with the headphone encoder. The top item in the list is

the next file to be recorded. Directly below that is the last recorded file or file currently being recorded, followed by all

previously recorded files.

Press Edit or push the headphone encoder in to access submenus for each file.

To Playback A File From The List

Scroll to a file and press Play to play it back.

Name

Edit the file’s name.

Number

Edit the file’s number. File numbers are reset to 001 when a new Project is created.

38 – Playing back files: Transport controls

39 – Copy media to your computer after recording

The MixPre can act as a USB storage device, so there is no need to pull out the SD card, simply connect the MixPre via USB-C to your computer.

40 – Configure recorder with custom settings

Advanced channel configuration will allow us to configure inputs 1/2 for stereo recording with a gain and balance control

Advanced recording options will allow us to select a sample rate and bit depth other than 48/24 in case we want to record sound effects that benefit from a higher sample rate or we want to give 32-bit float recording a try

Basic gain setting will configure the faders as simple gain controls which will be easier give our recording scenarios

Configure the recorder to operate in Custom Mode (SYSTEM ⇒ CUSTOM MODE) then

configure the recorder so that fader knobs work as simple gain controls (SYSTEM ⇒ CUSTOM MODE ⇒ BASIC GAIN MODE) configure the recorder so channels can be configured advanced recording formats can be selected (SYSTEM ⇒ CUSTOM MODE ⇒ ADVANCED RECORDING MODE)

Enables custom configurations (we will make use of this in the workshop, custom modes can be saved and reloaded to simplify recorder use.)

41 – MixPre-3 II Block Diagram

The MixPre series are professional mixer/recorders that provide many features and configuration options which professionals demand. We’ll configure and save three presets to simplify our use of this recorder.

42 – “STEREO-MIC” Config Signal Flow

This is the simplified signal flow in our STEREO-MIC configuration.

Notes: The MixPre series of recorders from Sound Devices are designed for professional production and, therefore, they offers many configurations for the wide range of use cases professionals encounter. Out of the box, the MixPre-3 II is a three-input, five-track output (Stereo Mix + 3 ISO channels) recorder/mixer. It can be expanded to a five-input (3 XLR in with pre-amps and stereo 3.5mm line in), seven-output track (Stereo Mix + 5 ISO channels) recorder/mixer with a plug-in. When the stereo mix and ISO tracks are being recorded, the MixPre recorders produce PolyWAV files.

In this class, we will keep things simple and use the MixPre as a two-track recorder with three custom configurations that are optimized for the microphones in the Advanced Audio Kit. If you would like to explore other use cases, please don’t hesitate to reach out to me.

43 – “STEREO-MIC” configuration

Advanced channel configuration will allow us to configure inputs 1/2 for stereo recording with a gain and balance control

44 – Saving Presets to the SD Card

The MixPre II’s flexibility is enhanced by its ability to save presets. If you plan to use the MixPre in a variety of situations, you can store and recall snapshots of all of the MixPre II’s settings. Setup files can be saved and recalled from the SD card (settings are saved to the SETTINGS folder, make sure to copy this before returning the MixPre or formatting the SD card) or to one of four internal preset slots. You can also restore the MixPre II to the factory default settings from the Presets menu.

Load — Loads factory defaults or user presets from SD Card or from on of four internal slots.

Save to INT 1-4 — Saves the current setup to internal slot 1, 2, 3, or 4.

Save to SD — Saves the current setup to the SD card.

45 – Configuring bit-depth and sampling rate

32-bit float is a digital audio format that uses 32-bit floating-point numbers to represent the amplitude of the audio signal. Unlike traditional 16-bit or 24-bit recordings, which can clip when sound levels exceed their maximum amplitude, 32-bit float recordings can handle extreme levels without clipping. This means they can accurately capture very quiet and loud sounds without distortion.

46 – Configuring bit-depth and sampling rate

The practical dynamic range we can expect with 24-bit recording is about 120 dB, 144 dB is theoretical. For scenarios when you can’t predict levels (e.g. sound effects recording), 32-bit float is a good option, offering a way to record the full dynamic range the microphone is capable of without clipping (you still need to worry about microphone self-noise and overmodulation on SPLs higher that the mic is designed for)

47 – 32-bit float audio in post-production

about the meter settings on the right: This signal is probably too low for dialogue adn most sound effects unless it’s quiet background ambience. 2. This is a realsonably healthy level in terms of peaks. 3. This is getting pretty hot, but as far as peaks are concerned, you’re still OK, and any larger peaks will hopefully be taken care of with the limiter, which should be engaged. 4. These peaks are too lound, your’re exceeding 0dBFS, and triggering the limiter, if engaged, otherwise, signal is distorting.

In 32-bit float recording, the precise setting of input gain is less critical. Even if the audio level is too high or too low during recording, the dynamic range allows for corrections in post-production without degrading audio quality. The floating-point format allows makes it easier to apply effects, compress, or boost audio levels during mixing without introducing noise or artifacts. For most dialogue and sound recording, 32-bit Float is overkill, but it is a useful tool for specific use cases. Ignore the hype and take the criticism of this format with a grain of salt. Since 32-bit float audio can capture sounds beyond the normal clipping point of traditional recordings, any signal that appears clipped in Adobe Premiere Pro or DaVinci Resolve or in a DAW (Digital Audio Workstation) can be recovered by adjusting the gain, unlike with 24-bit or 16-bit recordings where clipping distortion is permanent. Quiet sounds can be amplified without introducing noticeable noise, and loud sounds can be reduced without clipping. This flexibility gives you more freedom to correct recording mistakes. That said, it is not yet universally used in postproduction, so if you are doing work for another student or a client, always ask what delivery format they want, never make assumptions on delivery formats.

48 – Summary of our three custom presets

We will configure and save three custom modes:

STEREO-MIC {knob 1 GAIN, knob 2 BALANCE} — for stereo recording using the BP4029 configured in LR-N or LR-W mode with a single gain control for left and right channels; 1/2 LINKED, no ISO channels (all channels configured with arm = off), recorder creates a standard two-channel stereo WAV file;

ONE-MONO-MIC {knob 1 GAIN} — When recording with one mono mic, and no ISO channels (all channels configured with arm = off), the recorder creates a standard two-channel stereo WAV file (ch 1 and ch 2 are the same; this is called a “Dual Mono” file technically) that appears as a stereo file to most editors;

TWO-MONO-MICS {knob 1 Mic 1 GAIN; knob 2 Mic 2 GAIN} — When recording with two discrete mono mics (e.g., recording with TR-50 on interviewer and RE50 capturing vox-pop interviews) with separate gain control for each mic, mic on input 1 routed to channel 1 in the WAV file and mic on input 2 routed to channel 2 in the WAV file, no ISO tracks (all channels configured with arm = off), a standard two-channel WAV file is recorded that appears as a stereo file to most editors.

Presets can be saved to the SD card and copied so that they may reloaded during future recording sessions, so don’t forget to copy the SETTINGS folder when downloading media. I sometimes save the SETTINGS folder with my media so I can set up the recorder the same way it was setup for the recordings in the future.

49 – Location sound recording gear

Can you name and explain the role of each of these items?

50 – Location sound recording activity

The handout lists the sounds to be recorded and the mic and recorder config. recommended for each scenario; keep a detailed log of your takes!

Keep track of the format, microphone, recorder configuration, file name, date, place, and other details using the sound report form provided, additional copies may be downloaded from Canvas.

Depending on the context, you may want to SLATE your takes (add a verbal description of what you’re recording at the beginning or the end) which helps in identification of files without having to listen to the whole thing, make a note of audio slates in your sound log.

The recorder shows you the file name, making it easy to enter the names in your sound log.

Sound is far more difficult to scan than video, therefore, a good sound log will make postproduction far more efficient, enter description and log notes from your log into your Premiere Pro project bin after each sound recording session.

Note on the illustration: When recording ISO tracks, you list what or who each channel is assigned to (in our case we have a simple Ch1/Ch2 mix, but if you use two separate mics, indicate this in the report.

Sound report image courtesy of Location Sound Corporation, from the video “Sound Report - The Fundamentals,” https://www.youtube.com/watch?v=GN1pitPiPsE

51 – Working with discrete MS and stereo recordings in post

Working with discrete MS and stereo recordings in post

You can use a plug-in to decode MS to Stereo or encode Stereo to MS (this is often done to allow you to emphasize the middle or sides of a stereo recording)

Voxengo MSED (free, installed in Shillman 205 and 225):

https://www.voxengo.com/product/msed/

Goodhertz Midside Matrix (free):

https://goodhertz.co/midside-matrix/

52 – Resources for further study (1/2)

Resources for further study, page 1 of 2

Sound Devices MixPre II Series (PDF, sound devices), the user guide should be consulted when exploring additional features and capabilities, https://cdn.sounddevices.com/wp-content/uploads/2022/01/MixPre-II-User-Guide_01.04.22.pdf

Setting up the Sound Devices MixPre-3 (website, Macaulay Library, Cornell University),excellent starter guide covering config of the MixPre-3 for field recording, https://www.macaulaylibrary.org/resources/audio-recording-gear/mixpre3-setup/

MixPre II Series Playlist on YouTube (videos, Sound Devices), MixPre II Series Playlist on YouTube (videos, Sound Devices), https://www.youtube.com/playlist?list=PLKpAunZPiGRmKS3BfCF4OBjNdNz1VXbm1

Sound Devices MixPre-3 Setup Guide (video, Aaron Miller), provides a step-by-step guide for setting up the MixPre-3 II recorder, https://www.youtube.com/watch?v=L6L6tOmFx4c&t=454s

Recording Sound on Location (video, Lizi Hesling), an excellent tutorial on the fundamentals, https://www.youtube.com/watch?v=TKBzjSSaKXU&t=3s

Notes based on Recording Sound on Location (video, Lizi Hesling) are available in Canvas;

How to Be a Boom Operator (video, Diety Microphones), a brief introduction to crucial job on set, https://www.youtube.com/watch?v=QtMH7PtOoyA

53 – Resources for further study (2/2)

Resources for further study, page 2 of 2

UCLA Post Production: How To Wrap A Cable (video, David McKenna), all microphone cables should be wrapped using this technique, which can be applied to any cable! https://www.youtube.com/watch?v=uy3axdxDdKs

Location Audio Recording with Anthony Q. Artis (LinkedIn tutorial), an excellent LinkedIn learning course with practical examples, https://www.linkedin.com/learning/video-production-location-audio-recording/

Comparison of four microphone placements (video, David Tamés), compares the sound perspective of four commonly used microphone placement options, https://vimeo.com/605280702

Studying Sound: A Theory and Practice of Sound Design (book, Karen Collins), the best introduction to sound and sound design, https://amzn.to/3Bho9xu

Audio Bootcamp Field Guide (book, Ty Ford), the best, most concise guide on sound for video, https://tyford.square.site/#JYgbEl

Producing Great Sound for Film and Video (book, Jay Rose), a classic covering sound recording, editing, and mixing, https://amzn.to/3BbFCYa

Rycote Softie Windshield vs. Foam Windscreen (video, David Tamés), demonstrates the impact of using a windjammer when the wind picks up unexpectedly, https://vimeo.com/474862038

54 – Copyright, Note, Acknowledgments

Acknowledgments: I would like to thank Philip Perkins, G. John Garrett, Bill Shamlian, Peter Rea, and Alex Griswold, five audio professionals from whom I’ve learned so much about audio recording and posting over the years. Any wisdom in this area I owe to them, any bad habits are strictly my own. // © 2025 by David Tamés, Some Rights Reserved. THIS WORK IS PROVIDED UNDER THE TERMS OF A CREATIVE COMMONS PUBLIC LICENSE (“CCPL” OR “LICENSE”). YOU ARE FREE TO SHARE THIS WORK UNDER THE CONDITIONS OF ATTRIBUTION, NON-COMMERCIAL USE, and NO DERIVATIVE WORKS. // This version is released under “no-derivative-works” terms, however, if you would like a version released under “share-alike” terms, please contact me at d.tames@northeastern.edu //

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