Turntables

I looked at a picture of your receiver and it shows a phono input on the back. It will need to be a moving magnet or a high output moving coil design, for it to work with your Onkyo.

If I may ask - why do you only consider Pro-ject turntable?
Any $100 MM would do, I wouldn't buy $800-$1000 cartridge at this point unless you intend to get phono stage soon.

I agree with Inna..

While the Perspex 6 is a fine table with a tonearm capable of a $800-$1000 cartridge, I agree with the others and stick with a $100-$150 entry level MM cartridge at this time. Biggest reason being your electronics - your using the on-board phono stage in an AVR; electronics not exactly known for their analog performance. You would never get the most of a higher dollar cartridge.

Also, the Perspex's 9CC EVO tone arm is very low mass at only 8 grams so it should be matched with a high compliance cartridge. Ortofons and Sumikos come to mind. You might want to start with an Ortofon 2M Red at $99. You can upgrade the cartridge to three higher levels by changing the stylus, all the way up to the 2M Black at $750 that's sports a Shibata stylus. That is of course once you get away from the AVR.

Excellent guidance in the above posts. Cartridge sonics are a matter of personal taste. Since we know nothing of yours, it would have been presumptuous for anyone to jump in with, "Buy a ____, best cartridge ever!". Glad to see nobody went down that path.

OTOH, any phono cartridge, whether a $100 MM or a $10,000 LOMC, will only perform its best when paired with compatibile components. The two most closely related components are:
1) the tonearm (which provides the mechanical connection to the system); and
2) the phono stage (which provides the electronic connection to the system).

The posters above correctly addressed these components and their impact on your decision. This forum continues to provide guidance that's a cut above...