Mobile App Audio Tips

Audio Production for Mobile Apps

Audio for iOS apps is often overlooked but can be a valuable asset to any project.
Here are a few thoughts to help indie developers as they think about audio for their projects.

Acquiring Sound Effects

An indie iOS developer has several choices for acquiring sound effects for the app. Below, I discuss three basic options: purchase a large library, purchase sound effects individually, or hire a sound designer. Here are some advantages of each option:

Option 1: Buying Libraries

Purchasing a large library gives you the best value on a per-sound-effect basis, however, you will probably be paying for a lot of sounds you will probably not use. Small libraries of around 100 sound effects can cost around $150 while larger libraries can be more than $5000.  Some libraries can get a developer a lot of what they need, especially if the app only calls for a few UI sounds.  For Example: Digieffects Clickshop Library from Sound Ideas.  However, most libraries will still require some basic audio editing to trim the sound to just the desired portion.

The following are two leading sound effect companies that sell libraries:

Sound Ideas
Hollywood Edge

A sound designer will own a number of these libraries because they contain raw unedited recordings of hard to access sound sources, like a herd of elephants or an underwater blow-torch. From these raw recordings a sound designer can edit and manipulate the sounds into individual sound effects.

Option 2: Purchasing Individual Sound Effects
Purchasing sound effects individually is much more expensive per file compared to libraries, but may keep the total audio asset expense lower, if you know what it is you want. Online sound effects sellers, like Sound Dogs, will allow you to search their database and preview low-res versions of each sound before buying.

Sound Dogs –  an online sound effects retailer.


Option 3: Hire a Sound Designer
Hiring a sound designer can actually be surprisingly inexpensive in comparison to the first two options when you consider the total costs. Sound designers own large sound libraries and typically calculate bids based on work time. A Sound Designer’s library is something he’s continually investing in as part of the profession – so they already own many of the libraries you may be considering purchasing. Secondly, most sounds that a developer purchases still need to be edited and processed so they’re ready for implementation. This is a simple task for a sound designer but may be a timely and mistake-prone venture for the inexperienced.

Purchased libraries do come with one significant limitation: Standard SFX Library licenses allow the sound designer to use the sounds for any project they wish but the sound designer may not copy the source sound files to another computer or depot. Only the edited and compressed build assets may be in the depot. In other words, according to the license agreement that most sound libraries have, technically the sound designer must implement the sounds directly from their own machine.

Acquiring Music

There are several options for acquiring music. As a developer you want to purchase a royalty free license for sync rights, which of course is different than owning the music outright. Purchasing royalty free Sync Rights allows you to use the music in your app but it does NOT allow you to sell or distribute the music outside of your app: it must be synchronized with a visual.

Both Hollywood Edge and Sound Ideas sell royalty free music trakcs.  Another popular web music licensor is Jamendo.

Jamendo –  A seller of royalty free music.

If you’d like to own the complete rights to a song, or have an original and unique theme for your app, you need to hire a composer.  Many composers prefer to sell exclusive sync rights over work-for-hire but anything can be negotiated.

How expensive is it??  If you’re looking for “simple background music” working with a composer can be a viable option on a shoe string budget. Working composers can build from loop libraries and tailor short compositions in a short period of time.  Composers are commonly accomplished musicians and can write and produce music extremely quickly, especially if you just need a short loop.

However if you’re looking for a lot of original music, here’s a few things to think about.  Composer’s will take a few things into consideration to figure out how much time it will take to wire and produce the music:

Total minutes: how much music does the client need.

BPM’s: higher beat’s per minute generally means there is more music to write per minute.  The composer will have an idea for BPM’s, they’ll just ask you about how intense and fast passed you’d like the music.

Genre: different instruments take more time to produce convincing performances.

So how much does it cost to hire a composer? It really varies greatly from composer to composer and according to the previously mentioned factors.  However, as a very general ball park, 1 minute of original music can cost $100 to $500.

Audio Middleware

There are several audio engines available for license that will allow you access to more advanced audio features.  These features include things like enormous codec support,  playback randomization, dsp effects, and realtime parameter controls, to name a few.  Below are some of the more popular audio middleware engines:

FMOD EX –  iOS, Android –  $500/platform

WWise –  iOS  –  $500

Miles Sound System –  iOS  –  $5000


Three Tips for working with a Sound Designer

1) Pre-Production: Consider hiring a sound designer to write a pre-production audio design doc. Hiring an audio professional to work with you in establishing an audio production plan can be a great way to think through all of your options. This investment can easily pay for itself.

2) Contract: Make sure you and your sound designer both understand your contract agreement fully before proceeding. Include things like a detailed asset list, a reference list, a delivery schedule, and a payment schedule.

3) Revisions: Include time for revisions in your audio budget. Often times with app development time is short and you need to get audio started before other important decisions are made.  Other times, you may have an epiphany and you need to make some changes to some the sounds you requested.  Do your best to provide a wealth of references of what you’d like before work is done but always budget in time for revisions.

Free Audio Tools

Here’s are several free audio tools that are useful for various sound tasks:

Audacity –  An excellent audio editor.

SoX –  A cross-platform command line audio converter.

Switch –  A batch audio converter.

Mp3 Trim –  A utility to make mp3’s loop seamlessly.

ReaPlugs –  A set of amazing VST plug-in effects from Cuckos. (DAW host required… check out Reaper!)

Ardour –  A free DAW for Linux and Mac.

Leave a Comment