Sound Particles Density

While Basic mode is great for simple ensemble creation, Detune mode offers much greater control over the same process.

The idea of a harmonising plug‑in might not be new — but how about one with multi‑channel support and up to 100 voices?

Whether built into your DAW of choice, or a third‑party offering, there are now plenty of plug‑ins that can create doubles and/or harmony effects from a single audio source, but Sound Particles’ new Density plug‑in has a number of interesting twists. First, its underlying engine is built on particles and granular synthesis (technologies which are used in some of Sound Particles’ other plug‑ins). Second, it offers three distinct operational modes, called Basic, Detune and Multipitch, each offering more features to the user than the previous one. Third, as well as being capable of the usual mono/stereo input and output, this plug‑in supports a whole range of multi‑channel audio input/output formats, including binaural, various ‘.1’ channel counts (including 5.1 and 7.1) and Ambisonics. So if you want your plug‑in‑generated sound layers to be placed and to move around in a spatial audio environment, this may well be the plug‑in for you.

Modes

For the user, Basic mode is a simple as it gets. You can choose to generate either a small or large ensemble from your source audio, to add a bass (octave‑down) layer, and the amount of detuning applied. If you simply want to thicken up a vocal, then, this can be really very effective. It works very well with lots of other types of source, though; I found it effective for solo string, bass and synth parts. The quality of the additional generated voices is very good — whatever technology Sound Particles are using under the hood, it works.

The sense of ‘space’ created by the processing is impressive, whether you generate just a couple of extra voices or more — you can create up to 100!

Things get more intriguing in the Detune and Multipitch modes. Detune mode gives you more control over both the number of voices and degree of detune, courtesy of an X/Y pad. You can also control how those additional voices move in the virtual space; whether you’re working in stereo or a spatial audio format, this is represented in real time via a neat circular display. The sense of ‘space’ created by the processing is impressive, whether you generate just a couple of extra voices or more — you can create up to 100!

Multipitch mode allows the creation of up to eight harmony parts based upon your original audio input.

Multipitch mode takes the degree of control up another notch: it provides up to eight sets of generated voices, and each has its own Gain, Voice Number and Pitch settings. The last of these allows you to set pitch intervals between your source and the generated voices. Again, the quality of the pitched‑shifted audio seems very good, so there’s considerable potential here for creating harmony vocals or harmonies from melodic instruments (strings for example). However, in this initial incarnation at least, there doesn’t appear to be any formant correction applied to the pitch‑shifted output. Typical third or fifth above/below intervals seem convincing and artefact‑free, but this becomes more noticeable if you push things further. Equally, unlike with, say, Antares Harmony Engine, the pitch‑shifting isn’t scale‑aware — the pitch intervals simply track the pitch variations of the audio source at a fixed interval. You can automate the Pitch settings, of course, and this provides a fairly easy means of controlling the harmonies, but scale‑aware harmony generation and, perhaps, support for pitch targeting via MIDI, would be great to see in a future update.

Verdict

All Sound Particles’ plug‑ins seem to deliver something that little bit different and Density is no exception, particularly with its support for spatial audio formats. The creation of harmonies (for example, from a vocal) works well and sounds good, though if that’s your primary need there are other options that are more obviously focused on that task. What this the plug‑in does offer that is unique is its approach to simulating ensemble performances from single audio sources. If you’re looking to thicken a lead vocal, simulate a choir from a single voice, or just add a little texture to an instrument such as a synth or bass, the results can be truly impressive. And if that’s piqued your interest, you can check out the full 30‑day trial version which, of course, costs nothing!