# Pcmreadcallback is called only once
**URL:** https://qa.fmod.com/t/pcmreadcallback-is-called-only-once/16004
**Category:** FMOD Engine
**Tags:** csharp
**Created:** [July 24, 2020, 6:41am UTC](https://qa.fmod.com/t/pcmreadcallback-is-called-only-once/16004 "2020-07-24T06:41:25Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@LoVic](https://qa.fmod.com/u/LoVic)
#### Post date: [July 24, 2020, 6:41am UTC](https://qa.fmod.com/t/pcmreadcallback-is-called-only-once/16004/1 "2020-07-24T06:41:25Z")
Hello
Why is Pcmreadcallback called only once, after calling FMODsystem.createSound, and not for every data from the microphone?
```
FMOD.CREATESOUNDEXINFO exinfo = new FMOD.CREATESOUNDEXINFO();
exinfo.cbsize = Marshal.SizeOf(exinfo);
exinfo.numchannels = 2; // nativeChannels;
exinfo.format = FMOD.SOUND_FORMAT.PCM16;
exinfo.defaultfrequency = 44100; // nativeRate;
exinfo.pcmreadcallback += Pcmreadcallback;
exinfo.length = (uint)(exinfo.defaultfrequency * sizeof(short) * exinfo.numchannels);
byte[] data = null;
res = FMODsystem.createSound(data, FMOD.MODE.LOOP_NORMAL | FMOD.MODE.OPENUSER,
ref exinfo, out sound);
if (res != RESULT.OK) return false;
FMODsystem.update();
res = FMODsystem.recordStart(id, sound, true);
if (res != RESULT.OK) return false;
res = FMODsystem.playSound(sound, null, false, out channel);
```
---
### Author:  [@mathew](https://qa.fmod.com/u/mathew)
#### Post date: [July 27, 2020, 11:45pm UTC](https://qa.fmod.com/t/pcmreadcallback-is-called-only-once/16004/2 "2020-07-27T23:45:35Z")
System::createSound will request everything in one big chunk, the size of CREATESOUNDEXINFO::length. If you want continual reading, use System::createStream instead.