cartridge connections

I have a Nottingham Ace Space and an Art-7 and it just doesn't sound right. Bass is very thin and I'm thinking the connections are messed up, the tonearm wires no longer have the color codes, so I'm pretty sure they aren't connected correctly. How do I verify which is which?  I do have a multi meter.

I guess that didn't make sense, I have nothing to match up to, the leads come out of the tonearm loose and the color codes are gone.

OK, I assume you have RCA's on the tonearm cables. You should get some heat shrink tubing in Blue, White, Green and Red. Some clip sets come with the tubing. I think the Cardas set does.
Get your multi meter and set it to measure Ohms (continuity) Attach one wire to the center pin of the right channel RCA. Attach the other wire to each cartridge head shell wire one at a time. The wire that drops the meter to Zero is the right channel Hot or + lead. Put the red heat shrink on that wire (clip). Next do the outer connection of the right channel RCA. That will be the right channel ground or -. Put the green heat shrink on that clip. The center pin on the left channel RCA goes to the White clip and the negative left channel RCA goes to the blue clip. Rock and Roll!
I too thank you mijostynI

I didn’t even notice that all my carts were color coded.

Right+ Red
Right - Green
Left+ White
Left- Blue
Reverse orientation on rear of cartridge

Suitable for filing.