<font color='#000000'>FAQ: The Bass Management Dilemna
asked by Terry
Q: I read your article regarding LFE output. I am getting conflicting information from the people who make my receiver (Yamaha RXV520) and the people who make my surround sound speakers (Polk Audio RM6000). Polk says the sub-woofer should be connected to the system via the main speakers using speaker wire (not a RCA cable) or else I lose a bunch of mid-range bass. Yamaha says that is a fine way to hook it up but I lose the .1 of 5.1 surround sound. Polk Audio says that is not true and that even though the .1 is directed to the LFE output it will be redirected to main (set to large) since the LFE output is disabled (no wire). Can you help solve this mystery for me. Who is right?
A: Terry, I think I understand why there is a conflict between Polk and Yamaha.
Polk's Issue: If you hook up the subwoofer line level out of the Receivers subwoofer output, you will lose midbass information.
Polk may be worried that if you use the sub output on the Yamaha receiver, it may roll off the sub too low in frequency since the Yamaha has a built in Low Pass Filter (LPF) which would make for a poor blend in the mid bass region between your subwoofer and your main speakers.
I don't believe this is the case however for two reasons:
1. The LPF on the sub output from your Yamaha receiver is set at about 90Hz.
2. Your main speakers should play with enough Sound Pressure Levels (SPL) at 90Hz and probably down to about 80Hz I suspect. Therefore you should not have a frequency gap between the subwoofer and main speakers.
Yamaha's Issue: Hooking the subwoofer to the Receivers main speaker level outputs will result in a loss of the 0.1 LFE channel.
Yamaha may have misinterpreted how you planned to configure your speaker system. It is true that you will loose the .1 LFE channel if you set up the bass management in the Yamaha as having a subwoofer when you actually don’t connect your subwoofer to the subwoofer output of the Receiver. However, if you configure the bass management as illustrated below, you will not have this problem. In addition, the subwoofer will always operate in two and five channel modes.
[
More]</font>
