You’ll find our Impulse Responses available in two main “Versions”.

1. Sonic Palimpsest Impulse Response Library

Contains decoded .wav impulse files which can be imported in a wide range of different Convolution Reverb plugins.

2. Sonic Palimpsest – Altiverb IR Library

A duplicate of our IR library encoded in the custom format for easy import into the Altiverb convolution reverb plugin by Audio Ease.

We captured Impulse Responses in seven different historically significant sites across the dockyard. Each site has its own folder of impulse responses:

1. Ropery [built 1786]
2. Tarred Yarn Store [built 1786]
3. Number 3 Covered Slip [built 1838]
   • Mezzanine Level
   • Ground Floor
4. HMS Cavalier (CA-Class Destroyer) [built 1944]
   • Rear Mess
   • Front Mess
5. HM Submarine Ocelot (O-Class submarine) [built 1962]
   • Front
   • Rear
6. Commissioners House [built 1703]
   • Cellar
   • Billiard Room
   • Drawing Room
   • Second Floor Landing
   • Large Bedroom
   • Admiral’s Dressing room
7. Air Raid Shelter [built 1939]

We recorded these IRs using a variety of different microphone types and setups. Each “Site” therefore has been sampled from a range of different perspectives and microphone types.

• DPA 4061 – Stereo – Omnidirectional small capsule condenser microphones
• Neumann KM184 – Stereo – Cardioid condenser microphones
• Soundfield ST450 – 1^st Order Ambisonics (B-Format; Decoded to Binaural and Stereo)

Not only will the frequency response of each microphone vary, but the perspective and location from the sound source will change subtly too. Therefore, each set will have a slightly a different spatial position in relation to the impulse source.

Different microphone types will capture subtly different features of the environment. Omnidirectional IRs may have slightly better frequency response, while Cardioid may be more responsive in terms of time (i.e. have a sharper transient response).

Ambisonic recordings have also been used to create IR files in Binaural and Stereo.

N.B. Not all sites contain full microphone setups, as we were not able to record with all microphone arrays in every location. Please see APPENDIX for details on Impulse Response capture.

Impulse Responses are used within Reverb plugins to simulate the sound of spaces.

Any sound can be blended with any Impulse Response, creating a new output that combines the characteristics of both.

My voice (recorded in the studio) can be combined with the Impulse Response of a specific room, to create the impression that I am actually speaking in that other space.

An Impulse is played into the space to activate the acoustics and reveal its reverberant character.

Its response is captured using standard microphones and the recording (impulse + space) is later processed to leave only the recorded trace of the space.

There are two different ways to make an impulse response, either with a Burst or a Sweep.

Impulses can be captured using either short bursts of noise, or longer sine tone sweeps which rise from low to high. Both give you an image of the reflections in a space.

Noise bursts give you a momentary snapshot of the reverberation in a space and are quick to record, but don’t always contain so much detail across the spectrum (especially the lower frequencies).

Sine sweeps give you a more detailed gradual scan of the acoustic at the full range of different frequencies (the slower the sweep the better the resolution) but they can be more challenging to record. These sweeps also need to be converted before they can be used.

There are lots of different tools and programmes which will accept Impulse Responses. We have packaged up two versions.

1. Sonic Palimpsest Impulse Response Library
   • Contains deconvolved .wav impulse files which can be imported in a wide range of different Convolution Reverb plugins.
   • Often there is a drag and drop feature to add Impulse Reponses, but check the manual of your plugin for details on how to import our IR Library.

2. Sonic Palimpsest – Altiverb IR Library
   • Altiverb is a Convolution Reverb plugin created by the company Audio Ease. Their plugin uses some custom coding to convert the IRs and import them to a unique format.
   • If you have a copy of Altiverb, you can add our precompiled impulse response library directly into Altiverb by copying the files to the following destination:

Applications/Audio Ease/Altiverb 7/Impulse Responses/Third Party IR Libraries

Download Impulse Response Library

Download Altiverb IR Library

Sonic Palimpsest Impulse Response library © 2022 by Sonic Palimpsest team is licensed under CC BY 4.0

IR Library Recording Matrix

This matrix sets out the recording process for the sampled IRs.

N.B. All impulses have been deconvolved to create our IR libraries.