2. home-theater
  3. 1307134993

Subwoofer crossovers

I want to use my 2 JL113's with my 2 channel as well as my surround sound system. The JL's do not have an LFE input only L&R inputs. I think I need a crossover for the 2 channel system that I can shut down via remote so only the setting in the surround sound processor control the sub in theater mode. I use the right inputs for 2 channel stereo & the left inputs in a T configuration for mono with the surround system but the settings for 2 channel restrict the sub too much I think. I would like two differant crossover settings.
Any ideas or am I making this harder than it is.
Thanks for your input.
hevac1
rwwear
2,867 posts
 
You shouldn't connect the subs to two different preamps without an A/B switch. You can get an auto switch from Niles Audio that works well. The Velodyne SMS-1 will let you do what you want to do plus give you room EQ. It has multiple settings also.
Velodyne SMS-1
edorr
714 posts
 
I am using 2 JL 113 in an mixed 2 channel / multi channel system with my Parsifal Encores, using an external Xover and a bass EQ unit (the SVS). An important consideration in how you want to do this is whether or not you want to run your mains at full range along with the subs on 2 channel, or if you want to use the high pass from the Xover. Can you elaborate?

I presume for multi channel you will do all the bass managment and EQ in the Meridian SSP?

I think your best bet is indeed to use a switch and an analog cross over and some form of bass EQ for the subs in stereo mode.

Also, rather than summing the stereo signal I would run full discrete 2 channel stereo subs. You can split the mono LFE signal into a L/R signal into a stereo switch, and have a second stereo signal come in for use in 2 channel mode.
transaudio
96 posts
 
I should being this by saying I am from the pro side. Pros feel the best way is always to run the mains full range, use a Low Pass filter on the sub that's being fed the same full range signal. However, for movies, the correct movie set up uses a dedicated Low Frequency Effects channel, with the caveat being different studios have used different LFE crossover freq's in their mixes. The correct one is 120Hz for THX style but some have used 80Hz. This is also a summed mono channel. This whole area of LFE and crossovers etc is what's called "bass management", which many of us hate for lack of a universal standard. The idea of rolling off mains sucks! Inserting a crossover into mains at such an audible point leaves a good sized "hole" to sort out, a artifact you cannot fix.

Obviously this is a common problem so there is an entire class of product out there for it. Being that this 5.1, 7.1 processing is typically all digital, there will be a wide range of performance differences between processors.

The main point to make is DO NOT rolloff the mains or insert any type of crossover on the mains for anything but movies. It makes a big [audio] mess.

Brad

More to discover