Divide frequency of live audiostream from an ultrasound microphone

I want to record ultrasound with a microphone, divide the frequency and listen to the transposed sound. I start with a normal microphone for tests. I tried sox with rec and play so far. It works, but the latency is 2 seconds. rec -r 48000 -c 1 -t wav - pitch -1000 | play -t wav - How can I improve this line and reduce the latency? My audio setup is # API: ALSA v: k6.1.27-gentoo status: kernel-api # Server-1: PulseAudio v: 16.1 status: active