diff --git a/homeassistant/components/kef/media_player.py b/homeassistant/components/kef/media_player.py
index cf87a7dd447..1ba4d63ae4f 100644
--- a/homeassistant/components/kef/media_player.py
+++ b/homeassistant/components/kef/media_player.py
@@ -160,9 +160,11 @@ async def async_setup_platform(hass, config, async_add_entities, discovery_info=
     platform.async_register_entity_service(SERVICE_UPDATE_DSP, {}, "update_dsp")
 
     def add_service(name, which, option):
+        options = DSP_OPTION_MAPPING[which]
+        dtype = type(options[0])  # int or float
         platform.async_register_entity_service(
             name,
-            {vol.Required(option): vol.In(DSP_OPTION_MAPPING[which])},
+            {vol.Required(option): vol.All(vol.Coerce(dtype), vol.In(options))},
             f"set_{which}",
         )