Bass Management for Satellite HTiB Systems

We have fielded several questions relating to how to handle bass management for integrated sub/satellite system where the subwoofer actually handles the crossover and feeds signal to the satellite speakers. Bose and Definitive Technologies both have systems that deal with this (though they function quite differently) and we received a recent question that prompted us to write up a brief FAQ to address this issue.

From Phil: Wow, I'm confused. It seems from this article on bass management you recommend speakers be set to small. I tried this first, but it just doesn't sound good. So, I consulted the manual, and Def. Tech (ProMonitor 80) suggests that the satellites be wired through the sub - high level, and speakers set to large. This sounds much better. Does your recommendation trump the manual? If so, I've got some tweaking to do.

Right now, I have the sat. speakers wired through the sub, AND an RCA connection from my receiver (Marantz SR7300) LFE Pre Out to the sub. Front speakers are set to large, and sub=yes.

Am I wrong in assuming that the only time the LFE feeds the sub is in Dolby 5.1? Therefore, listening to 2 channel music, this connection is not used. BTW, movies sound great, music sounds good, but not great (trying to remedy this).

Audioholics: There are different types of sub/sat systems. I'll address a more common type of system first, then directly refer to your system in particular. There are several systems available that have a subwoofer and satellites configured such that the subwoofer contains the amplifiers and crossover network for the satellite speakers. You can instantly identify these types of systems because the rear of the subwoofer, unlike the majority of amplified subwoofers, will have speaker level output connections for the satellite speakers. Famous for this type of setup is the Bose Acoustimass as well as most gaming systems like the Z-5500 from Logitech.

With these systems it is important to note that the manufacturer intended bass management to be handled by the electronics contained within the subwoofer and/or system controller. In most cases, proprietary connections prevent you from even thinking about connecting the speakers directly to your receiver and often a lack of a line level RCA input on the subwoofer eliminates the possibility of using the subwoofers apart from the system as a whole.

The goal with these products is to send them full-range signal, so the integrated crossover network can do what it wants and get you what is likely to be the best possible sound from the integrated system. You can do this is a few easy steps.

1. Set all speakers to LARGE in your receiver. Remember, you need full-range signal to go to all speakers because it is really going to the subwoofer, which then strips out the low frequency and sends it to the sub. If you set your speakers to SMALL in a system like this, the sub will have nothing to work with.
   
2. Set your SUBWOOFER setting to NO so that all LFE information is passed through the main channels. Since the subwoofers in these systems do not have dedicated inputs, you have to get your subwoofer information to go to the main channels via the LARGE setting.
   
3. Position your subwoofer using tips from our article "Crawling for Bass".
   
4. Set the distance/delay settings for your speakers by adjusting these parameters (if available) in your receiver.

Unfortunately, there are rarely any additional options to help improve the sound at this point. You'll want to play with the location of the sub and perhaps adjust tone controls to achieve the best possible sound for your room. The upside is that these systems handle all most of the management controls for you. The downside is that... they handle most of the bass management controls for you! The important thing to note is that, in this case, the owners' manual really does trump our recommendations since the system is specifially configured to work only one way.

An additional type of system is one that comes with a recommendation to connect the main satellite speakers through the subwoofer where you connect the front speakers through the subwoofer's speaker level input/output connections. In this case, the subwoofer still has a line level input option for the LFE (.1) track but it can also serve to provide the crossover for the main speakers. Definitive Technology's ProCinema Systems are like this, to mention just one company. This is a bit more complicated and can be handled in a couple ways:

1. Read the manual and follow the manufacturer's instructions, or
   
2. Tweak your setup manually, connecting your subwoofer directly to your receiver and your mains as you would the center and surround speakers.

We don't really have a recommendation for every scenario, but will point out that if you connect the main speakers through the subwoofer you lose the ability to independent control the subwoofer level via the receiver. You are also using an analogue low pass filter (LPF) on the subwoofer instead of the digital 24dB/octave filters (THX standard) that are on many receivers. There should be nothing lost by connecting this system up directly using our recommendations so we'd say give it a shot and experiment to see which method yields more control and quality.