Programmer sounds not routed via effects

I am creating a programmer sound in order to use mic input via your example script ScriptUsageRecordMicrophone but this sound does not have any effect applied. I know this because I have added heavy tremolo to the master bus and can hear this happening on regular events that I trigger through unity. I can’t seem to find a way to link the created sound to any tracks or events that I have in fmod studio so believe that I am misunderstanding something about how fmod works quite substantially.

If anyone has any insight into how to add fmod studio effects to sounds created via CoreSystem.createSound that would put my half-day of fruitless investigation to rest!


Can you share the full script you’re using to pass the sound created with CoreSystem.createSound to the programmer sound?

Sounds made and played by the CoreSystem won’t be affected by any effects added in the FMOD Project. You’ll need to combine the ScriptUsageRecordMicrophone example with the Unity Integration | Scripting Examples: Programmer Sounds.

Check out this forum post where we discussed a similar issue: Adding Effects to Real-Time Recorded Audio.

Hope this helps!

Hi Connor

Thanks for your reply.

Your reply made me realised that although the mic recording is setup via code, it’s not a programmer sound! I have combined the two scripts which I will paste below.

This works fairly well although I am having a ~300ms delay even when I reduce the latency values as far as I can [Edit: latency was solved by adjusting DSP buffer values in FMOD settings].

Also I enter a “domain reloading” loop once every few play-mode exits which requires me to end-task unity.

If you have any insight into either of these then please let me know, otherwise the code is here as a start point for anyone else doing the same:

using FMOD;

public class MicRecording
    private readonly MicSettings micSettings;
    private readonly int driverId;
    public readonly int NativeRate;
    public readonly int NativeChannels;

    private uint samplesRecorded;
    private uint samplesPlayed;
    private uint recSoundLength;
    private uint lastPlayPos;
    private uint lastRecordPos;
    private uint adjustLatency;
    private int actualLatency;
    private uint minRecordDelta;

    private Sound recSound;
    private ChannelGroup recChannelGroup;

    private uint DriftThreshold => (uint)(NativeRate * micSettings.driftThresholdMS) / 1000;
    private uint DesiredLatency => (uint)(NativeRate * micSettings.targetLatencyMS) / 1000;

    public MicRecording(MicSettings micSettings, int driverId)
        this.driverId = driverId;
        this.micSettings = micSettings;

            Determine latency in samples.
        FMODUnity.RuntimeManager.CoreSystem.getRecordDriverInfo(driverId, out _, 0, out _, out NativeRate, out _, out NativeChannels, out _);
        adjustLatency = DesiredLatency;
        actualLatency = (int)DesiredLatency;
    public void Initialise(Sound sound, ChannelGroup channelGroup)
        recSound = sound;
        recChannelGroup = channelGroup;

            Create user sound to record into, then start recording.
        FMODUnity.RuntimeManager.CoreSystem.recordStart(driverId, recSound, true);
        recSound.getLength(out recSoundLength, TIMEUNIT.PCM);

    public void Tick()
            Determine how much has been recorded since we last checked
        FMODUnity.RuntimeManager.CoreSystem.getRecordPosition(driverId, out uint recordPos);

        uint recordDelta = (recordPos >= lastRecordPos)
            ? (recordPos - lastRecordPos)
            : (recordPos + recSoundLength - lastRecordPos);
        lastRecordPos = recordPos;
        samplesRecorded += recordDelta;

        //uint minRecordDelta = 0;
        if (recordDelta != 0 && (recordDelta < minRecordDelta))
            minRecordDelta = recordDelta; // Smallest driver granularity seen so far
            adjustLatency =
                (recordDelta <= DesiredLatency)
                    ? DesiredLatency
                    : recordDelta; // Adjust our latency if driver granularity is high

            Determine how much has been played since we last checked.
        recChannelGroup.getNumChannels(out int channelCount);
        if (channelCount == 0)

        if (recChannelGroup.getChannel(0, out Channel recChannel) != RESULT.OK)

        if (recChannel.hasHandle())
            recChannel.getPosition(out uint playPos, TIMEUNIT.PCM);

            uint playDelta = (playPos >= lastPlayPos)
                ? (playPos - lastPlayPos)
                : (playPos + recSoundLength - lastPlayPos);
            lastPlayPos = playPos;
            samplesPlayed += playDelta;

            // Compensate for any drift.
            int latency = (int)(samplesRecorded - samplesPlayed);
            actualLatency = (int)((0.97f * actualLatency) + (0.03f * latency));

            int playbackRate = NativeRate;
            bool slow = actualLatency < (int)(adjustLatency - DriftThreshold);
            bool faster = actualLatency > (int)(adjustLatency + DriftThreshold);
            if (slow)
                // Playback position is catching up to the record position, slow playback down by 2%
                playbackRate = NativeRate - (NativeRate / 50);
            else if (faster)
                // Playback is falling behind the record position, speed playback up by 2%
                playbackRate = NativeRate + (NativeRate / 50);
    public void StopRecording()
using System;
using UnityEngine;
using System.Runtime.InteropServices;
using FMOD;
using FMOD.Studio;
using FMODUnity;
using Debug = UnityEngine.Debug;

class ScriptUsageProgrammerSounds : MonoBehaviour
    [SerializeField] private MicSettings micSettings;
    [SerializeField] private int driverId;
    public EventReference eventReference;
    private EVENT_CALLBACK micRecordingCallback;
    private MicRecording micRecording;

    private static Action<string, ChannelGroup, IntPtr> _startMic;
    private static Action _stopMic;
    private void Start()
        // Explicitly create the delegate object and assign it to a member so it doesn't get freed
        // by the garbage collected while it's being used
        micRecordingCallback = new (MicRecordingEventCallback);
        EventInstance soundInstance = RuntimeManager.CreateInstance(eventReference.Path);
        // Pin the key string in memory and pass a pointer through the user data
        GCHandle stringHandle = GCHandle.Alloc("MicSound");
        // Previous MicRecordingEventCallback was not static and invoked these but this caused unity to crash
        // Using static actions resolve this, see
        _startMic = StartMic;
        _stopMic = StopMic;

    private void LateUpdate()

    private static RESULT MicRecordingEventCallback(EVENT_CALLBACK_TYPE type, IntPtr instancePtr, IntPtr parameterPtr)
        Debug.Log($"[MicRecordingEventCallback] callback type = {type}, instancePtr = {instancePtr}");
        EventInstance instance = new(instancePtr);

        // Retrieve the user data
        instance.getUserData(out IntPtr stringPtr);

        // Get the string object
        GCHandle stringHandle = GCHandle.FromIntPtr(stringPtr);
        string key = stringHandle.Target as string;

        switch (type)
                instance.getChannelGroup(out ChannelGroup channelGroup);
                _startMic(key, channelGroup, parameterPtr);
                Sound sound = new(parameter.sound);


                // Now the event has been destroyed, unpin the string memory so it can be garbage collected
        return RESULT.OK;

    private void StartMic(string key, ChannelGroup channelGroup, IntPtr parameterPtr)
        micRecording = new MicRecording(micSettings, driverId);
        CREATESOUNDEXINFO createSoundExInfo = new()
            cbsize = Marshal.SizeOf(typeof(CREATESOUNDEXINFO)),
            numchannels = micRecording.NativeChannels,
            format = SOUND_FORMAT.PCM16,
            defaultfrequency = micRecording.NativeRate,
            length = (uint)(micRecording.NativeRate * sizeof(short) * micRecording.NativeChannels)
        Sound sound = CreateSound(key, parameterPtr, createSoundExInfo);
        micRecording.Initialise(sound, channelGroup);

    private static Sound CreateSound(string key, IntPtr parameterPtr, CREATESOUNDEXINFO createSoundExInfo)
        RESULT soundResult = RuntimeManager.CoreSystem.createSound(key, soundMode, ref createSoundExInfo, out Sound sound);
        if (soundResult == RESULT.OK)
            parameter.sound = sound.handle;
            parameter.subsoundIndex = -1;
            Marshal.StructureToPtr(parameter, parameterPtr, false);
            Debug.LogError($"Cannot create mic sound: {soundResult}");

        return sound;

    private void StopMic()
        micRecording = null;
using System;

public class MicSettings
    public uint targetLatencyMS = 5;
    public uint driftThresholdMS = 1;


Thanks for sharing the solution.

This can be caused if all the sounds/channels are not stopped correctly. We can remove all the channel manipulation now that we are using the programmer instrument to play the sound. This might help solve the issue as we won’t need to track a channel.

All we need to do is:

  1. Create the sound
  2. Start recording using the sound
  3. Pass the sound to the programmer instrument

FMOD should take care of the rest.

Hope this helps.