Hi. I have a trouble how to output audio in Pure-data externals.
I made a program to process sound by convolution.
I added effects to an inputed audio in the frequency domain and put that audio back into the time domain.
At that time, the number of blocks for the audio grew. (64 blocks→129 blocks)
I put it directly into the output array out[] and it sounds weird.
How should I handle this?

@Hong-Hong Hard to tell, but [dac~] reblocks to 64 as do [inlet~] and [outlet~] so it seems likely that the "weird" audio is the convolution working.
But the weirdness might be because you have introduced delays within your patch. Objects need to be created in the correct order........
http://puredata.info/docs/manuals/pd/x2.htm chaper 2.4.4 onwards.
And there are some anomalies where the creation order is changed when the patch is modified........ unexpected and difficult to spot....
https://forum.pdpatchrepo.info/topic/13512/s-r-throw-catch-latency-and-object-creation-order
David.