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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
lewinskih01
909 posts
 
If your only source is your computer and you want to run "digital crossovers", the best approach is to run the digital xo inside the music software in your pc, then output to a multichannel DAC, and drive the sub/s on 2 channels and the LS50 on other 2 channels.

FWIW I started like this and now do 3-way active xo with a Lynx Hilo (DAC). 
martykl
3,578 posts
 
I hadn't ever considered it, but Lewinski's idea strikes me as potentially very cost effective.  If I understand the proposal correctly, you'd only need to add the DAC and a multi channel power amp of your choice.  

However, the one caveat here is volume attenuation.  If it's done in the digital domain, you may find that there's an audible impact on SQ (particularly at lower listening levels).  As with all things audio, this is personal and you might also find that it has no impact on SQ.

If attenuation is controlled by the software, then you're effecting it in the digital domain.   If volume control is at the DAC, it could be in either (depending on the design of the DAC) the digital or analog section, but you'd hope it would be analog - in any event you can check the user's manual to find out.

I've never tried it, so I'm not taking a position one way or the other, just pointing out that - if the volume control is in the software - this is the "rationalist's" trade-off in this otherwise very rational solution.
kahlenz's avatar
kahlenz
274 posts
 
I think you are going backwards.  The M3si is a perfect match for the LS50s.  The REL sub would seem to be a perfect match as well (using the high level input).  The trick here is moving the sub around until you get optimal room pressurization (I'm not going to get into room acoustics and DSP here, other than to say attention to both can yield remarkable results).  The other "trick" is having realistic expectations.  The LS50s are only going to throw out so much sound.  You could easily dial in too much bass with the sub.  I have a similar set up (Harbeth P3esr speakers. REL t5i).  I have both the crossover and level on the sub set at about 9 o'clock, just enough to add a bit of room pressurization.  Any more and the integration with the Harbeths is gone.

If you are looking for big, thumping bass or home theater type sound effects, you can turn the sub up.  But for most music listening, good integration is going to be a lot more pleasurable.
oddiofyl's avatar
oddiofyl
3,892 posts
 
I also agree the 2160 is a step in the wrong direction......  I had a 2150 and returned it..... not because of the sound, the Balance and Bass molex connectors were swapped during manufacture.  The Balance affected the bass and vice versa....  such a turn off I just sent it back. 
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