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Discussion Starter · #1 ·
Too many knobs, and not enough time to turn them! Burning the candle at both ends with too many hobbies and learning curves. Crash and burn, burn and turn, get the idea? :dumbcrazy:

THE PROBLEM
Can anyone help me with a complex (to me) bass management / subwoofer integration issue? The components in question here are an Emotiva UMC-1 pre/pro and a REL T-9 subwoofer. Both components offer so many connection/setup possibilities so as to make me dizzy. Basically, I'd like to know if I should set the sub's crossover controls for good sound before running Emotiva's auto room correction (called EMO-Q).

THE BACKGROUND INFO
I've exercised due diligence in finding a similar thread, but have only been able to dig up some issues others have had with the UMC-1's bass management. The following link details that functionality http://emotivalounge.proboards.com/thread/11627

Now in a bass-management nutshell...
in addition to the LFE signal, frequencies below the xover points of all 5 channels are routed to the sub. But also, those frequencies are sent with applied EQ settings even though they are below the crossover point. So the sub gets the LFE channel info PLUS equalized sound below the xover for each of the other five channels.

With that said, the REL uses a unique connection method detailed here
http://www.musicdirect.com/p-43114-rel-t9-subwoofer.aspx

Now in a subwoofer crossover nutshell...
The EQ and Xover for the LFE input is controlled by the pre/pro (which, by the way only extends down to 40Hz, whereas the sub is rated flat to 30Hz). The Xover for the special high-level input is controlled by a rotary knob on the sub.

THE QUESTION:
So given all those variables, how would you adjust for an optimal sub/mains crossover point? HINT: EMO-Q leaves much to be desired in my room with my system.
 

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THE QUESTION:
So given all those variables, how would you adjust for an optimal sub/mains crossover point? HINT: EMO-Q leaves much to be desired in my room with my system.
Hi Lou,

If you are unhappy with the way the EMO-Q is setting things, you should be able to manually configure the Emotiva XO settings (using the LFE input on REL to bypass its controls). Tweak by ear.
The biggest problem I see, is you are using a single sub. Which, despite all its "audiophile" credentials, cannot transcend basic laws of physics and wave propagation in acoustically small rooms. The best you might hope for, is response relatively free of peaks, in a single position. Getting this over a wider (HT) area is implausible/impossible.

Now in a subwoofer crossover nutshell...
The EQ and Xover for the LFE input is controlled by the pre/pro (which, by the way only extends down to 40Hz, whereas the sub is rated flat to 30Hz).
I think you may be confusing low pass with extension. The 40hz setting is mostly likely the lowest low pass crossover frequency of the processor, which means all frequencies below 40hz are allowed to "pass", down to the electrical response limit (10hz?) of the Emotiva (frequencies >40hz will be rolled off at a given slope). The subs acoustic output is specified flat to 30hz, at which point it will begin to roll of at an approximate slope, dictated by it's design (around 12db/oct for sealed, 24db/oct for reflex).

cheers
 

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Discussion Starter · #3 ·
aaahhhhh HAH! Thanks for that, AJ.

:ponder: You're right, I was confusing low-pass filtering with extension. If I now understand correctly, then setting the processor's crossover at 40Hz for the LFE channel, then a traditional sub's rotary crossover control should have diminishing effect over 40Hz.

I think I was also confusing the interaction between the T-9's LFE and HIGH-LEVEL inputs. The sub reproduces a blend of both. It's LFE input will reproduce the 5-ch sound as configured by the pre/pro's crossover settings. It's HIGH-LEVEL input will blend-in ONLY the L/R front signals, as adjusted by the sub's crossover and volume controls. :sneeky: In other words, I don't need to worry about the T-9's xover setting for the center or surrounds because that setting only affects what's being fed what the front channels are seeing!

And you are right again on the dual-sub issue. I agree. But I got lucky in my single-seat, 10x12 room. The listening position is not in a null or peak, and the fluctuations themselves are not severe throughout the room. But the frequency response is mediocre, and I need to better integrate the sub with the rest of the speakers.

I think the next step is to tweak speaker positions and crossover settings using REW as a guide. Do you think the Emotiva's graphic sub EQ is adequate, or should I consider adding an outboard EQ like a miniDSP?
 

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Hi Lou,

Well, I'm a bit dubious about the whole Hi/Low thing rationale (though I understand why they are doing this...and it's mainly to appeal to "audiophiles" and their strange beliefs about main amp "sound" character). I would suggest using the Emotiva for all controls/processing and using the RELs LFE input, which should bypass all it's internal controls except volume.
A 40hz low pass is pretty low, especially for a sub that rolls off below 30! That would utilize it over a very limited bandwidth. It also means your mains will need to be quite capable, as 40hz still requires quite a bit of excursion. Are you using towers (no system listed)?
Yes, integrating the sub into a system is always tricky and what is mediocre about your frequency response? Can you post a graph?

cheers
 

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Discussion Starter · #5 ·
Thanks again, AJ. Reasonable advice that I would have shrugged-off a year ago. I'll give your straight LFE suggestion a go 'round and report back.

>>> START BLAH-BLAH-BLAH (because that's how I roll) :snoring:
I used to have audiophile tendencies with my stereo rig until it was moved into a horrible listening environment with extreme bass anomalies. After learning about and applying acoustical treatment, I now keep an open mind. Many enthusiasts know that room treatment can easily trounce component upgrades. The high end audio industry would rather keep their customers in-the-dark and on the upgrade merry-go-round. :shh:

My introduction to room treatment, REW, and hometheatershack.com have put EQ and DSP on the radar for my stereo system. I'm learning they're a given for rewarding HT, but some methods/devices are better than others. I'm anxious to see (....errr hear) what can be accomplished. I don't have graphs yet, because I'm still on the flat part of REW's learning curve (is that a pun?).
>>> STOP BLAH-BLAH-BLAH :snoring:

You opened my eyes that I'm not using my pre/pro as intended. EMO-Q has been crossing the sub at 65Hz with the mains set to full range. Guess what? I'd crank it back down to 40Hz every time. No wonder I'm getting mediocre bass. By mediocre, I mean bloated and lacking impact. Full-range bass to the mains is robbing the amp of headroom. The REL used to pressurize the air, punch me in the chest with authority, and make the cement slab shudder. I think I need to revisit placement, too.

Anyway, I'm way off-topic, so I better stop for now. I'll give your LFE suggestion a try and also post my system components, then report back. Thanks again! :wave:
 

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