iv a b&w cm9 5.1 set up with a rel t5i sub and im not sure about setting it up to its full potential?
someone told me I need to find what the cm9 front speakers roll off level is and match it to the sub ?
can someone one please help
If you want to maximize it and remove guess work from equation you would be best sourcing Umik microphone and measuring it to get all the answers but it is time consuming process as you would have to read and learn the basics. Otherwise put it in the corner if you can and use Audyssey or similar to get results fast with minimal effort.
Sounds like they were talking about crossover settings. If you have speakers that can only play down to 70Hz, setting a crossover at 70Hz would be a bad idea. Your CM9s (assuming the floorstanders) go down to 56Hz so a standard 80Hz crossover will be fine. Audyssey should sort this out for you.
When it presents the crossovers when Audyssey has finished its measurements, look out fo values either very high or low. 80-110 is a good range.
I've had a REL T5 for over eight years now and Audyssey XT32 has always done a good of EQing the sub. It's not the biggest and best for film but with 5.1 music from DVD concert videos of SACD multi channel it's integrated just right. I have all my speakers crossed over at 80hz.