diff --git a/src/filter/seriesbiquad.rs b/src/filter/seriesbiquad.rs
index ee482a0..3228c2e 100644
--- a/src/filter/seriesbiquad.rs
+++ b/src/filter/seriesbiquad.rs
@@ -1,20 +1,17 @@
-
 use super::*;
 
 use super::biquad::Biquad;
 use anyhow::{bail, Result};
 
-
 #[derive(Clone, Debug)]
 #[cfg_attr(feature = "python-bindings", pyclass)]
 
-
 /// Series of biquads that filter sequentially on an input signal
 ///
 /// # Examples
 ///
 /// See (tests)
-/// 
+///
 pub struct SeriesBiquad {
     biqs: Vec<Biquad>,
 }
@@ -109,7 +106,16 @@ impl Filter for SeriesBiquad {
         Box::new(self.clone())
     }
 }
-
+impl<'a, T: AsArray<'a, Flt>> TransferFunction<'a, T> for SeriesBiquad {
+    fn tf(&self, fs: Flt, freq: T) -> Ccol {
+        let freq = freq.into();
+        let mut res = self.biqs.first().unwrap().tf(fs, freq);
+        for i in self.biqs.iter().skip(1) {
+            res = &res * i.tf(fs, freq);
+        }
+        res
+    }
+}
 
 #[cfg(test)]
 mod test {
@@ -138,4 +144,4 @@ mod test {
         inp[1] = 0.5;
         assert_eq!(&inp, &filtered);
     }
-}
\ No newline at end of file
+}