Hello,
It seems the LoopingAudioSource cannot really cope with buffer requests bigger than what was set in the prepareToPlay call.
However, when connecting the LoopingAudioSource to a ResamplingAudioSource, the buffer size requested at each getNextAudioBlock can vary wildly 
I have made a small crude patch for this problem. Please let me know if this makes sense.
I have pasted below the original version, followed by the version with my small fix.
Thanks for your comments
Benjamin Golinvaux
void LoopingAudioSource::getNextAudioBlock (const AudioSourceChannelInfo& info)
{
if (info.numSamples > 0)
{
if (isLoopingBetweenTimes)
{
const ScopedLock sl (loopPosLock);
const int64 newStart = getNextReadPosition();
int64 newEnd = loopStartSample + ((newStart + info.numSamples) % loopEndSample);
if (newStart > loopEndSample)
newEnd = newStart + info.numSamples;
if (newEnd > newStart)
{
input->getNextAudioBlock (info);
}
else
{
const int64 numEndSamps = loopEndSample - newStart;
const int64 numStartSamps = newEnd - loopStartSample;
tempInfo.startSample = 0;
tempInfo.numSamples = (int) numEndSamps;
input->getNextAudioBlock (tempInfo);
tempInfo.startSample = (int) numEndSamps;
tempInfo.numSamples = (int) numStartSamps;
input->setNextReadPosition (loopStartSample);
input->getNextAudioBlock (tempInfo);
for (int i = 0; i < info.buffer->getNumChannels(); ++i)
info.buffer->copyFrom (i, info.startSample,
tempBuffer,
i, 0, info.numSamples);
}
}
else
{
input->getNextAudioBlock (info);
}
}
}
void LoopingAudioSource::getNextAudioBlock (const AudioSourceChannelInfo& info)
{
if (info.numSamples > 0)
{
if (isLoopingBetweenTimes)
{
const ScopedLock sl (loopPosLock);
const int64 newStart = getNextReadPosition();
int64 newEnd = loopStartSample + ((newStart + info.numSamples) % loopEndSample);
if (newStart > loopEndSample)
newEnd = newStart + info.numSamples;
if (newEnd > newStart)
{
input->getNextAudioBlock (info);
}
else
{
const int64 numEndSamps = loopEndSample - newStart;
const int64 numStartSamps = newEnd - loopStartSample;
tempInfo.startSample = 0;
tempInfo.numSamples = (int) numEndSamps;
if (tempBuffer.getNumSamples() < (tempInfo.startSample + tempInfo.numSamples))
tempBuffer.setSize (2, tempInfo.startSample + tempInfo.numSamples);
input->getNextAudioBlock (tempInfo);
tempInfo.startSample = (int) numEndSamps;
tempInfo.numSamples = (int) numStartSamps;
if (tempBuffer.getNumSamples() < (tempInfo.startSample + tempInfo.numSamples))
tempBuffer.setSize (2, tempInfo.startSample + tempInfo.numSamples);
input->setNextReadPosition (loopStartSample);
input->getNextAudioBlock (tempInfo);
for (int i = 0; i < info.buffer->getNumChannels(); ++i)
info.buffer->copyFrom (i, info.startSample,
tempBuffer,
i, 0, info.numSamples);
}
}
else
{
input->getNextAudioBlock (info);
}
}
}