to add to my previous post:
Running under Unity v. 2018 1.0f2 (d4d99f31acba) Personal

Same problem (most recently described by SOAPBOXCLOUDBUILDMAR 24, 2017) is occurring when running on IOS (11.3.1) on the iPad Generation 5.

Hi
problem Solved :
your Audio file must Standard Setting .
if you convert a Audio file to Other format ,you should not change setting in convertor , Because unity Not Support other setting and show follow Error :

Error: Cannot create FMOD::Sound instance for resource Ȝ B , (Unsupported file or audio format. )

I am encountering a similar issue in Unity 5.5.2f1.

Device: iPad Air 2
OSX version: 10.1.1

It occurs when I attempt to load a wav file saved under Application.persistentDataPath using WWW. Relevant code snippet and debug output included below. Note - the issue is not experienced during the session the files are originally saved in, only during subsequent sessions.

The file is definitely being loaded by WWW, as localFile.audioClip is not null. What seems odd to me is that the error message occurs between the LOAD COMPLETE and FILE LOADED SUCCESSFULLY output, when they should be executed immediately after each other.

Code:

WWW localFile = new WWW(path);

Debug.LogWarning("LOADING FILE AT " + path);
yield return localFile;

Debug.LogWarning("LOAD COMPLETE");
if (!string.IsNullOrEmpty(localFile.error) && OnFileLoadFailed != null) {
if ((SBSettings.DebugOutput & DebugFlag.FileManager) != 0) {
string message = "File manager: File not loaded - " + localFile.error;
SoapBoxManager.AddToLog(message);
Debug.Log(message);
}

OnFileLoadFailed(localFile.error);
}
else if (localFile.audioClip == null && OnFileLoadFailed != null) {

if ((SBSettings.DebugOutput & DebugFlag.FileManager) != 0) {
string message = "File manager: File at path " + path + " is not an audio file";
SoapBoxManager.AddToLog(message);
Debug.Log(message);
}

OnFileLoadFailed("File at " + Application.persistentDataPath + "/" + path + " is not an audio file");
}
else if (OnFileLoadSuccess != null) {
Debug.LogWarning("CLIP LOADED SUCCESSFULLY: " + localFile.audioClip);
yield return 0;
OnFileLoadSuccess(localFile.audioClip);
}

Log output:

LOAD COMPLETE
SoapBoxLabs.<_LoadFile>c__Iterator0:MoveNext()
UnityEngine.SetupCoroutine:InvokeMoveNext(IEnumerator, IntPtr)

(Filename: /Users/builduser/buildslave/unity/build/artifacts/generated/common/runtime/DebugBindings.gen.cpp Line: 51)

Error: Cannot create FMOD::Sound instance for resource `9, (Operation could not be performed because specified sound/DSP connection is not ready. )
SoapBoxLabs.<_LoadFile>c__Iterator0:MoveNext()
UnityEngine.SetupCoroutine:InvokeMoveNext(IEnumerator, IntPtr)

[ line 878]
(Filename: Line: 878)

Error: Cannot create FMOD::Sound instance for resource `9, (Operation could not be performed because specified sound/DSP connection is not ready. )
SoapBoxLabs.<_LoadFile>c__Iterator0:MoveNext()
UnityEngine.SetupCoroutine:InvokeMoveNext(IEnumerator, IntPtr)

[ line 878]
(Filename: Line: 878)

CLIP LOADED SUCCESSFULLY: (UnityEngine.AudioClip)
SoapBoxLabs.<_LoadFile>c__Iterator0:MoveNext()
UnityEngine.SetupCoroutine:InvokeMoveNext(IEnumerator, IntPtr)

(Filename: /Users/builduser/buildslave/unity/build/artifacts/generated/common/runtime/DebugBindings.gen.cpp Line: 51)

Error: Cannot create FMOD::Sound instance for resource `9, (Operation could not be performed because specified sound/DSP connection is not ready. )
SoapBoxLabs.<_LoadFile>c__Iterator0:MoveNext()
UnityEngine.SetupCoroutine:InvokeMoveNext(IEnumerator, IntPtr)

@TIM-BLUENOSE , I have the same question as you, Do you find any way to solve yet?

@Firtina

I have posted a response on the existing forum as I feel that it is a related yet separate matter to this one.

https://forum.unity3d.com/threads/fmod-sound-instance-for-resource-error-with-asset-bundles.431456/

Thanks

Can anyone confirm 5.5 or any of its subsequent patches contain the fix? I upgraded after releasing an update in 5.3.x and the issue is occurring again. I've tried 5.5.0f3 and 5.5.0p2. Has anybody actually tried and tested 5.5 for this?

Thanks