I don't think I tried that setting. I think what they wanted was when you have a THX Ultra 2 or flat sub down to 20 or lower it gives you the option for boundary Comp (bass attenuation). Switch off THX Ultra 2 and you can not select boundary comp. I just leave mine set for full frequency extension or THX. I don't think turning it off does anything different. Does any one know when it is off what it does? It may limit the low frequency output to protect a sub or compress it in some way. I just never tested it off to see what it did. I just know my bass is correct with THX Ultra two turned on. Sorry!

Cheers,

Ron

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