Sound Effects

Unidentified Sound Object (U.S.O.) is an independent sound effects library publisher serving a worldwide clientele. Founded in 2011 by Matteo Milani, with over 20 years of experience in advanced sound design, U.S.O. offers high-quality, commercially-usable sound libraries. Matteo specializes in post-production audio, continually crafting innovative sound effects libraries featuring both analog and digital synthesis, and unique recording techniques. All files are tagged with detailed metadata for easy searching and conform to the Universal Category System for sound classification.

Listen to Those Who’ve Chosen Us

How wonderful is your idea of breaking sounds into layers. The problem with libraries is they lock you into someone else’s idea. If you can give flexibility on how sound pieces can be assembled that is so cool, and unique in libraries. – Gary Rydstrom

Your library is super impressive… blown away really. I just loaded up the Radium patches… crazy good! You’ve done some great creative work there, chef’s kiss! – Justin Drury

Thanks for sharing all of the ins and outs of creating this library. HUGE undertaking, but fantastic results! – Chris Stangroom

I have got 2 of your libraries, they are both one of my favourites, can’t get my fingers of them and use them (nearly) everywhere! – Lars Fischer

Can’t wait to check it out!!! As soon as I heard the demo on designing sound I didn’t even listen to the whole thing before I snagged it! – Chris Fonte

Nice library of stuff! – David Farmer

Look forward to more libraries you’ll have to offer in the future. I’ve been impressed. – Ryan Bloomer

Just grabbed Unseen Noises. Great stuff. Wow. – Kelly Pieklo

Thank you for these awesome sounds! – Franz Danksagmüller

Keep up the great work with your sounds, loving the unusual stuff you do!!! – Byron Bullock

View as:

Cinematic & Trailer Sound Effects Cosmic Charges Play Track 79-570 sounds included From: $69
Introducing “COSMIC CHARGES,” an innovative sound effects library meticulously developed by Matteo Milani at U.S.O.‘s headquarters. This collection represents a major advancement in our commitment to crafting distinctive audio assets that that reinvent our approach to sound design. “COSMIC CHARGES” uniquely specializes in tonal blasts and impacts, each thoughtfully created from the ground up to ensure unmatched creativity and originality in your projects.

Designed to enrich a variety of media, such as video games, films, TV series, and more, each sound in “COSMIC CHARGES” integrates musical elements, providing a unique sonic identity that can intensify emotional resonance, enhance dynamics, and add richness to your works.

Discover the features of “COSMIC CHARGES”:

Organic and Synthetic Fusion: Experience a unique blend of real recordings and synthesized sounds, offering a versatile palette for cutting-edge sound design.

Electric Guitar and Percussion Elements: Created in collaboration with proficient musicians, these components add genuine, vibrant energy to your projects.

Customizable Layers: Each sound is available in both a full stereo mix and isolated tracks, providing quick and extensive customization options.

Infinite Headroom: 32-bit float BWF to ensure your sounds remain pristine without any risk of clipping.

UCS Metadata: the definitive metadata standard we’ve embraced for seamless integration and organization in your workflow.
Select options
Creature Sound Effects Whispering Spirits Play Track 125+ sounds included $49

Introducing the Whispering Spirits sound effects library. Immerse yourself in a realm where every sound echoes tales of ancient spirits and long-forgotten memories. This meticulously curated collection showcases haunting whispers and distant murmurs of spirits, all uniquely generated using only the human voice. Expertly crafted by Matteo Milani on the renowned Kyma sound design workstation, each sound in this library originates from a long session of improvisation and performance, making for a truly organic and immersive auditory experience.

Designed for sound designers with a taste for the supernatural, this library effortlessly bridges the realms of the living and the otherworldly. Whether for horror films, atmospheric games, or projects seeking the essence of spectral memories, Whispering Spirits offers a unique auditory experience that stands apart.

Add to cart
Other Instruments Back and Forth Play Track 400+ sounds included From: $29

Back and Forth was born of an idea of Matteo Milani and Lorenzo di Tria (aka Dj Mate/Signal Generator), thinking on how to build an intuitive and great sounding music tool for contemporary producers and sound designers.
Based on Lorenzo’s experience on the art of turntablism and Matteo’s ability to produce distinctive sound effect libraries, this collection is now an easy way to add real scratch and turntable performances to your musical and audiovisual projects, and finally make them sounds better then ever before.
The unsurpassed sound of the needle in the groove and the cuts of the crossfader generate an unmistakable music quality and uniqueness.
The library follow the naming structure provided by UCS (Universal Category System), a public domain initiative supported by sound librarians, vendors, and users from around the globe.

Select options
Drones & Mood Sound Effects Kyma Ambiences – vol.2 Play Track 100 sounds included From: $49

Kyma Ambiences vol.2 follows the traces of the original collection dated back 2013, but this time it’s bigger and immersive. It contains 100 abstract and evolving ambiences created with our beloved Kyma sound design workstation. Due to the increasing demand of spatialized content for game and VR/AR project, this inspiring collection has been entirely designed as a spherical representation of sound natively in 3rd Order Ambisonics by generating all the Sounds in Kyma and mastering them in Pro Tools through a custom analog setup (Looptrotter Sa2Rate+Elysia xfilter 500+TK Audio BC501).

Ambisonics is a multi-channel technology that lets you spherically capture the sound arriving from all directions, at a single point in space. I used state of the art tools to forge these modern and cinematic soundscapes by blending many encoders to inject different colours into the design process. Each virtual 3D sound environment has been carefully constructed by layering and placing Kyma Sounds at different locations in a virtual three dimensional field using the Audio Ease 360 pan suite. I captured real spatial sound with the AMBEO VR Mic to be encoded-transformed-decoded using Kyma Ambisonic Tookit (1st Order) and then up-mixed to 3rd Order with Harpex-X and PerfectSurround Penteo 16 Pro to extract the maximum amount of spatial information.
– Matteo

“Kyma Ambiences – vol.2” is available in three variants:

Stereo Edition:
2 channels interleaved files (100 items)
Size: 3.48 GB

1OA (first-order) B-Format AmbiX:
ACN channel order & SN3D weighting/normalisation: W/Y/Z/X
4 channels interleaved files – ready to use stereo versions are included as well (100 items)
Size: 6.94 GB

3OA (third-order) B-Format AmbiX:
ACN channel order & SN3D weighting/normalisation: W/Y/Z/X/V/T/R/S/U/Q/O/M/K/L/N/P
16 channels interleaved files – ready to use stereo versions are included as well (100 items)
Size: 27.82 GB

If you want to use the 1OA b-format file directly in your VR/AR project, simply keep only the first 4 channels (WYZX) dropping the other ones (TRSUQOMKLNP)

Audio Format: Interleaved Broadcast Wave Files (.wav)
Sample Rate: 96 kHz
Bit Depth: 24-bit

Select options
Car Sound Effects Monaco Grand Prix 2018 Play Track 334 sounds included From: $99

We’re proud to release our first premier race ambience library, as we continue our exciting journey in sound experimentation with spatial audio. The Monaco Grand Prix 2018 is a genuine sonic document of the 76th edition of the Grand Prix Automobile de Monaco, the world’s most glamorous race.
If you’re looking for unique and modern race engine sounds and ambiences to use in your commercial, movie, television or game projects, here you’ll find lot of sounds with different perspectives to start building real and tactile sport soundscapes.
We made use of two favourite Ambisonics microphones: the Sennheiser Ambeo and the classic Soundfield SPS200, recorded across our Sonosax gear (SX-R4+, SX-R4, SX-M32) and their amazing preamps, which digested the high SPLs of the high-performance cars.
But that’s not all: you’ll also find extremely accurate stereo recordings made with a Sanken CSS-5, an A-B Stereo Technique configuration with a couple of omnidirectional DPA 4060 and, last but not least, a custom MS rig based on a Schoeps MK 41 supercardioid capsule (Mid), plus a MK 8 figure-8 capsule (Side), amplified by their respective CMC 6 units.
Looking for radical transformations? We recorded everything @ 96 kHz, so if you want to turn a pass-by into a dramatic spaceship pass, you’ll be free from any sonic artifacts.

Select options
Bundles Ambisonics U.S.O. Bundle $326

The Ambisonics U.S.O. Bundle includes Insectus, Runaway Trains, Monaco Grand Prix 2018 & Kyma Ambiences – vol.2 from Unidentified Sound Object. This multi-pack combo provides selected sound libraries at a savings of 25% off the retail price.

Add to cart
Bundles Hum, Buzz & Glitches U.S.O. Bundle $202

The Hum, Buzz & Glitches U.S.O. Bundle includes Unseen Noises, Transmission Apparatus, 3Dimensional Printing, ACME and Back and Forth from Unidentified Sound Object. This multi-pack combo provides selected sound libraries at a savings of 25% off the retail price.

Add to cart
Drones & Mood Sound Effects Drones & Moods U.S.O. Bundle $133

The Drones & Moods U.S.O. Bundle includes Hologram Room – vol.1, Kyma Ambiences – vol.1 | Stereo Edition & Kyma Ambiences – vol.2 | Stereo Edition from Unidentified Sound Object. This multi-pack combo provides selected sound libraries at a savings of 25% off the retail price.

Add to cart
Train Sound Effects Runaway Trains Play Track 216 sounds included, 118 mins total $79

Immerse yourself in the second library of the Ambisonics series by USO. These “Runaway Trains” were recorded with a Senneheiser Ambeo and a Sonosax R4+ in and around the Milano Greco Pirelli railway station, which is part of the so-called “Milan Circle Line,” a railway loop which circumnavigates the city.
The library contains a lot of passing trains and ambient sounds recorded very close to the railway, both by day and by night. There has been no further processing, although I did carefully remove all the Italian P.A. announcements, to make life easier for the editors during the sound montage.
A useful bonus, too: you will find some ready-to-use backgrounds as “airfill” between the passing trains to create continuity in a longer scene, if need be. The ambient sounds are also great as a standalone!

Select options
Ambisonic Sound Effects Insectus Play Track 300 sounds included, 50 mins total $69

Do you want to add a bit of mystery, depth, tension to your ambience stem and influence the emotional state of the listener?

Insectus is a special Ambisonics sfx library: we’ve been through lot of experimentation in that time with different approaches regarding the best way to deliver this bizarre package of sounds.

So what is it exactly? Just think about the sound-designed material as a background sweetener. We’ve called it Insectus not only for its Latin roots, but also because it comes from the fusion of two word: Insect+Tinnitus.

We used the higher octave of the spectrum in an odd way, mimicking insect vocalization and biophony sounds in Symbolic Sound Kyma by layering a lot of synthesised stream of small band of very high frequencies (hence the inspireful source name Tinnitus).

Now you can create soundscape by layering, rotating, expanding and shrinking the FuMa/ambiX file. You can also re-construct the 360° sound panorama from binaural up to 7.1 surround.

You’ll find 100 loopable variations of FOA FuMa/ambiX interleaved files (4 channels), with a duration of 30 seconds each.

Select options
Water & Ocean Sounds (M)exican (S)easide Play Track 52 sounds included, 70 mins total $39

Mexican Seaside is a unique Mid-Side collection of ocean sounds gathered during the summer of 2017 in the Yucatán Peninsula – Mexico. It contains sandy and rocky beach ambient sounds, with no human activity. These sounds were recorded at sunrise (on various days) with a Zoom H6 on a Joby GorillaPod and a MS capsule (MSH-6) covered by a Rycote Mini Windjammer. Mid-side allows you to actually adjust the width of the stereo image after it has been recorded. It provides total mono compatibility for recordings that may eventually be played back in mono, such as TV broadcasts.
The package contains a MS-RAW folder plus a LR folder with all the files decoded to stereo for quick use.

100% of “Mexican Seaside” SFX library purchases will be donated to UNICEF México.

Add to cart
Cinematic & Trailer Sound Effects Warped Choir Play Track 247 sounds included From: $69

A filmic sound construction kit for teasers, trailers & promos

‘Warped Choir’ is the latest state-of-the-art sound effects library from U.S.O. which continues to cross the border between music and sound design.

Warped Choir provides a wide range of meticulously crafted stereo and 5.1 surround sound elements ready to be pumped in your trailer, video game or other audiovisual projects.

Warped Choir contains more than 200 massive dynamic impacts, transitions, soundscapes, epic vocal rises and whooshes, all designed from scratch using a choir concert recording as the unique waveform source in the Symbolic Sound Kyma workstation (many thanks to La Coral Salvé – Laredo, Cantabria | www.coralsalve.com).

When it comes to creating new musical ideas, video and sound editors, sound designers, but also composers, can find inspiration in this intriguing must-have collection.

Select options
Hum, Buzz & Glitch Sound Effects ACM(E) Play Track 26 sounds included $15

This small sound library contains all the original CPU fan and hard disk noises emitted by the following vintage Apple MACs, each with its own unique texture:

• Power Macintosh 4400
• Power Macintosh 6400
• Power Macintosh 7200
• Macintosh Classic
• Macintosh Mac G4
• Macintosh Mac LC 475

The material contains a lot of mechanical noises and different startup chimes, plus a lot of boot sequences with all the hard drives/fans spinning and whirring.

Add to cart
Mechanical Sound Effects 3Dimensional Printing Play Track 95 sounds included $49

3Dimensional Printing is the multicolored result of different recording sessions of a couple of 3D printers (the Sharebot NG – Next Generation and the DeltaWASP 20 40) at Fabb and at FabLab Milan between 2014 and 2015.
All the sounds were recorded directly as uncompressed .wav files through both a RME Fireface UCX and a Zoom H6 Portable Recorder.
Duration ranges vary from 1 to 5 minutes, with the most sonically interesting excerpts from full printing cycles. Lots of pattern and sequences are available for selection and transformation.
Five different transducers were chosen to capture all the sonic details of these mechanisms:
– C-SERIES pro contact microphones, hand-made by Jez Riley French;
– Barcus Berry 4000 Planar Wave System (Piezo crystal sensor+4000XL Piezo Preamp);
– Piezo Film Tab Contact Microphones by Cold Gold Audio;
– Custom Induction Coil Pick-up (also used to create the Unseen Noises collection);
– Zoom MSH-6 MS Capsule (the stereo image of the Mid-Side recordings is rendered as balanced stereo LR files).

Add to cart
Hum, Buzz & Glitch Sound Effects Transmission Apparatus Play Track 373 sounds included From: $49

Transmission apparatus is a construction kit designed to create a broad range of communication sounds, from real to “alien” broadcasting signals.

The library contains more than 2 GB of data, delivered in 373 files of unique sound material. It’s catalogued in five elements: AM (amplitude modulation), FM (frequency modulation), SSB (single side band – aka ham radio), KYMA (synthesised noises) and VOCAL (unintelligible speeches).

The first three bands were recorded from the output of different radio receivers at 96 kHz via a Crane Song HEDD (Harmonically Enhanced Digital Device) to add warmth and tube/analog sonic color to the recordings. All the samples have been carefully selected from these recording sessions, with the addition of just a little dsp processing to widen the stereo field.

The Kyma folder also contains unique audio files entirely synthesised in the SSC Kyma+Paca(rana) environment. A group of SFX called Vocal is the result of “destroyed” dialogues and vocal sources via spectral processing.

Transmission Apparatus is available in two versions:

96 kHz .WAV version• Audio Format: Broadcast Wave Files (.wav)
• Bit Depth: 24-bit Size: 2.49 GB
• Download size is 1.82 GB (compressed .rar archive)

Native Instruments Kontakt 5 version• Audio Format: NI Instruments File (.nki)
• Sample Rate: 96 kHz
• Bit Depth: 24-bit Size: 1.66 GB
• Download size is 1.64 GB (compressed .rar archive)
• Full version of NI Kontakt 5 required

Select options
Drones & Mood Sound Effects Kyma Ambiences – vol.1 Play Track 56 sounds included, 112 mins total From: $49

Kyma Ambiences [USO003] is the third sound effects bundle created by Matteo Milani.

The generation of these “Artificial Reality Ambiences” starts entirely in Symbolic Sound Kyma from the processing of white and pink noise by filtering – in the time/spectral domains – and convolving these sources with custom FM, additive, formant and granular synthesis.   The composition’s resource of sound material is drawn solely from these processed stochastic sound elements: coloured noise is a raw material already full of life and can be sculpted into a variety of temporal forms, movements and textures.

The interaction with Kyma was typical of a composer who explored a device’s potential for sound transformation like a musical instrument. The goal was to obtain an organic and acoustic quality using only a restricted sound source, in order to evoke real spatial characteristics attached to each invented sound.

The “Kyma Ambiences vol.1” sound effects collection is published @ 96kHz (native) – and is also available as dual-layer separated “Elements”, suitable for recombinant stratification, varispeed and spatial positioning in the surround field (for a total of 112 files @ 96kHz).

Select options
Hum, Buzz & Glitch Sound Effects Unseen Noises Play Track 40 sounds included $40

Electromagnetic informations are invisible and omnipresent. In every city, especially the big ones, an infinite number of electromagnetic waves is hidden: we can’t hear them, but they’re everywhere! Unseen Noises explores the “invisible” noise pollution transducing electromagnetic fields into audio signals with a telephone pickup: it acts like a radio antenna for hum and weird electromagnetic noises.

“We used telephone tap coils that receive electromagnetic signals around us and convert them into audible information to discover invisible and surprising aspects of the environment in which we live in.

To widen our sound palette, we explored cell phones, tablets, light systems, automated teller machines, wireless communication systems, anti-theft security devices, surveillance cameras, computers, navigation systems, wireless Internet routers, neon advertisings, public transportation networks.

We just used the system of electromagnetic induction as way of amplifying musical sounds. Our efforts were focused on finding “articulated” behaviours and other musical qualities in them.

Note that the files contained in “Unseen Noises” are real performances executed on different devices without editing.” – Matteo Milani

Add to cart
Drones & Mood Sound Effects Hologram Room – vol.1 Play Track 431 sounds included $35

Hologram Room [USO001] is the first bundle of the abstract Sound Design Collection produced by Matteo Milani.
These two gigabytes of “ready to use” original sound elements are designed to help you sweetening and enhancing your sound production. The whole library is organized in eight main folders: Active Drones, Alarms, Blips, Buttons, Communications, Ignitions, Telemetries, Transitions. It provides a selection of out of this world drones and ambiences, futuristic sound effects and electronic tools.

Add to cart

View as:

EU VAT exempt? See prices without VAT

With A Sound Effect, Asbjoern has created a web site where our international community can browse, learn, and share the vast fruits of our labors. Together we are accelerating the very real potential power of sound design as a recognized art form.

Wylie Stateman

Supervising sound editor,
The Hateful Eight, Inglourious Basterds, Kill Bill: Vol. 1

A Sound Effect is an excellent resource for us to keep our animated films sounding unique and exciting.

Gabriel Guy

Re-recording Mixer, Walt Disney Animation Studios:
Frozen, Big Hero 6

A Sound Effect is a great asset to have discovered.

We found the site very easy to navigate, purchasing and downloads were effortless and the effects themselves are awesome! Asbjoern has done us all a great service.

We’ll definitely be back!

Wayne Pashley

Supervising Sound Editor/Re-recording Mixer, The Lego Movie & Mad Max: Fury Road

There are many great independent sound effect libraries available these days. The main problem with having so many, is keeping track of them!

A Sound Effect is a great hub, and is one of the first places I visit to look for sounds by category or genre. I started coming here to see if I could find libraries that I knew I had heard, but forgot WHERE I had heard them.

And in the process discovered libraries I never would have found otherwise. Great work! Keep it up!

David Farmer

Sound designer:
Lord of the Rings & The Hobbit trilogies

We're always looking for new sounds to mangle, so when A Sound Effect had a holiday sale, I tried them out.

The purchase experience is really smooth and quick, and delivery is almost instant.

I'll definitely come back to them again in the future!

Charles Deenen

Director, Digital - Source Sound Inc.

A Sound Effect is a wonderful resource for indie sound effects libraries. On top of that, it has some of the finest sound design, film and game audio interviews!