simple question re: negative voltage on 741 op amp

Hi there, excuse my complete newness, but, I had troubles with this issue a while ago, and seeing as ppl are more than helpful here..

I wanted to build the electronic percussion synth from the classic forest m mimms "getting started in electronics", but, well, as a side note, I find that book maybe not as easy to understand as others Ive found since.. But, I realize I could make a power supply delivering positive and negative 9v, but do I really need to do this for this circuit below? or when the 741 goes to -9v on pin 4, because "-" is just a voltage difference, in my case of just wanting this standalone circuit, could I just connect it to ground?

or, really, do I have to build a negative -9volt into the circuit?

thanks!
**broken link removed**

Yes, you do require a negative voltage in order to bias the internal transistors of 741 in active region.

thankyou