Smart ESCs included with E-Flite planes are not compatible with the MrRCSound systems but there is an easy workaround for the issue. The Smart ESC uses different signals than a typical ESC and will cause erratic behavior with MrRCSound sound systems. Both the V4.1 and the ASPIRE are affected.
Throttle response does not work properly and in some cases the startup sound will repeat over and over. You may not get any sound at all. These issues appear when using a Y servo wire to split the throttle signal between the sound card and the receiver.
This work around requires the use of a programmable radio transmitter. You will need a spare channel available on the transmitter and receiver for the sound card. Plug the servo wire from the sound card directly into a free channel on the receiver. Enter the settings menu on your transmitter, per the transmitter manufacturer’s instructions, and mix the throttle to the channel used for the sound card.
What you are doing is duplicating the signal from the throttle channel to the sound card channel while eliminating the interference caused by the Smart ESC. When this is complete, please adjust the trim and sub trims of sound card channel to get a close sync between the prop start and startup sound. This is a very simple but effective workaround.