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A little confused on how to properly integrate my sub

Hi everyone! Im relatively young and inexperienced when it comes to the more complicated electronics side of audio. Right now for my computer desktop Im using a a pair of LS50s connected to a Musical Fidelity M3si integrated amplifier. I also have an REL T9i connected to the finding posts of the amp and use the High level input like REL dictates.

Ive decided that I really want to properly crossover my speakers and let the sub handle ONLY the low end. I decided to put my Musical Fidelity up for sale and have ordered an Outlaw RR2160 that has integrated bass management. I plan on using a standard unbalanced RCA cable from the Outlaw to the REL. The problem is REL makes this very difficult. Unlike another sub I have where there is a switch that lets you use a filter in the sub or amp, the REL provides no such option. They demand you use play your speakers full range. The knobs on the back of the sub are LO/HI Level (volume I think), Crossover (30hz to 120hz), and .1LFE level (im not plugging into that input anyway).

I assume what I need to do is set the crossover frequency on my Outlaw to 80hz (where I want it), and then plug the Outlaw into the REL through the low level input, then crank the crossover on the sub to 120hz. The sub should only be receiving the low frequencies anyway so by cranking the subs crossover up all the way I shouldn’t be attenuating any frequencies. Does this sound right to you guys? THANKS!
EDIT: After thinking about it, is there any reason not to use the LFE input and bypass the subs filtering? As I understand it, all LFE content is 120hz or below so the sub designers took that into account.
collingraff
avanti1960
1,405 posts
 
unfortunately you are going in the wrong direction if you want seamless integration between sub and the LS50s (which is completely possible!).  
the issue is your subwoofer- it lacks the necessary adjustments needed for proper integration.  critical controls like a polarity switch and continuous phase angle adjustment.  
REL used to offer these controls- it is a shame yours does not have them.  
rather than getting the outlaw amp (sending your LS50s through more electronics is not optimal) i would suggest a sub like the JL audio D110, which has the proper controls for perfect integration.  
If you use the foam plugs on the LS50s, they will have an acoustic crossover frequency of ~ 75 Hz- where the bass drops like a rock.  set your crossover on the sub to ~ 75Hz.  your default setting for the subwoofer should be reverse polarity (helps avoid peaks and valleys) and then rotate the phase control until the sound is seamless.  
if you get a sub with the proper features you can keep your current amp.  getting a new amp with sub crossover is a losing battle without the right sub.  unless you aren't particular - but you already are because you want to make a change.  change the sub, not the amp.  

tutetibiimperes
202 posts
 
You are correct that you don’t want to run your speakers through the sub if you can avoid it.  Hook the LS50s directly to the RR2160 and the sub directly to the RR2160 via the LFE or RCA low level input, set the crossover on the sub to its highest value, and then use the crossover dials on the RR2160 to set the actual crossover point you want.  

@avanti1960 is right in that the REL doesn’t seem to have a phase or polarity switch.  That may or may not be an issue depending on where it’s placed and your room.  Try it out and see how it works first.  
tutetibiimperes
202 posts
 
Another option would be to get an integrated amp with the smarts to automatically adjust phase and polarity.  The Yamaha R-N803 or the Elac Element EA101EQ would both be great choices, and both cost around the same as the RR2160.  They both also have room correction built in to even better improve your sound. 
collingraff OP
2 posts
 
@avanti1960 Thanks for the recommendation. I mostly got this sub because it was a ridiculously good deal and didnt put a whole lot of thought into how it would fit into my system. For the time being, is going from the outlaw crossed over at 80hz into the LFE input a decently acceptable option? I know going into the low level input is going to take me through another crossover. I figure that the LFE input probably has less in the signal path and isnt going through some sort of filter since its a standard. 
rhljazz
1,249 posts
 
Tithe -3 dB point for the LS 50 is 79hz.  Just let them roll off naturally and use the REL as the manufacturer intended.  You’re headed in the wrong direction.
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