There are so many cars in Malaysia and all of them could be used to TEST Birds call. As long it has a stereo player in it. It cost nothing to make this Sound Test Kit "which I named it" . I had been using it for many years it works perfectly and the sound is good if you have a branded stereo player in your car. Nowadays most stereo players come with high RMS (RMS is power out put by Stereo) 25-50w x 4 channels, so to boost up your little tiny tweeter is no problem. Here I would like to share with all readers how to make it "DIY".
It is simple less than 1 minute to fix it. Best of all unlimited numbers of tweeters you can use but be reasonable-lah 3-4 tweeters are good enough. Use any side of your Speaker (rear) un-plug the wire and attached the wire to the wire that connects to your tweeters. Make sure it is long enough so that the STK could be put on top of your car.
For those who want to have a clearer pictures of how it works you may email me at swifjames@yahoo.com.