diff --git a/firmware/baseband/proc_am_audio.cpp b/firmware/baseband/proc_am_audio.cpp
index 3a073db4..bb207102 100644
--- a/firmware/baseband/proc_am_audio.cpp
+++ b/firmware/baseband/proc_am_audio.cpp
@@ -86,7 +86,7 @@ void NarrowbandAMAudio::configure(const AMConfigureMessage& message) {
 	channel_filter.configure(message.channel_filter.taps, channel_filter_decimation_factor);
 	channel_filter_pass_f = message.channel_filter.pass_frequency_normalized * channel_filter_input_fs;
 	channel_filter_stop_f = message.channel_filter.stop_frequency_normalized * channel_filter_input_fs;
-	channel_spectrum.set_decimation_factor(std::floor((channel_filter_output_fs / 2) / ((channel_filter_pass_f + channel_filter_stop_f) / 2)));
+	channel_spectrum.set_decimation_factor(std::floor(channel_filter_output_fs / (channel_filter_pass_f + channel_filter_stop_f)));
 	modulation_ssb = (message.modulation == AMConfigureMessage::Modulation::SSB);
 	audio_output.configure(message.audio_hpf_config);
 
diff --git a/firmware/baseband/proc_nfm_audio.cpp b/firmware/baseband/proc_nfm_audio.cpp
index 2a0349ac..ce9c6634 100644
--- a/firmware/baseband/proc_nfm_audio.cpp
+++ b/firmware/baseband/proc_nfm_audio.cpp
@@ -76,7 +76,7 @@ void NarrowbandFMAudio::configure(const NBFMConfigureMessage& message) {
 	demod.configure(demod_input_fs, message.deviation);
 	channel_filter_pass_f = message.channel_filter.pass_frequency_normalized * channel_filter_input_fs;
 	channel_filter_stop_f = message.channel_filter.stop_frequency_normalized * channel_filter_input_fs;
-	channel_spectrum.set_decimation_factor(std::floor((channel_filter_output_fs / 2) / ((channel_filter_pass_f + channel_filter_stop_f) / 2)));
+	channel_spectrum.set_decimation_factor(std::floor(channel_filter_output_fs / (channel_filter_pass_f + channel_filter_stop_f)));
 	audio_output.configure(message.audio_hpf_config, message.audio_deemph_config, 12288);
 
 	configured = true;