Subwoofers that do both L/R & LFE simultaneously?

Running a 2 chan/HT combo. I understand the REL subs allow you to connect both the stereo high level inputs and an LFE cable and the unit apparently senses the signal. You send the sub a full range signal. Any others do this? My Para s8's don't really need help on 2 chan, but it makes sense to me to use a REL type setup with the sub crossover at around 30. That way I get a little fill-in as needed. Am I missing something, why aren't all subs done this way. Thanks, this forum is great!
The Wilson Watch Dog has a processor LFE input as well as a stereo line input,....but you have to switch between them as you change from HT to two channel....not ideal, but it does permit two setups. By the way, I find the Watch Dog to be a terrific supplement to Watt/Puppies...similarly at 30.
I'm not quite as familiar with the RELs as you apparently are, though I'm not a fan of sending speaker level signals to subs.

I do know that both the Martin Logan Depth and Descent subs (I have a Depth) include line level (and speaker level) inputs for 2 channel; as well as a separate, single, line level LFE input; plus an LFE output for daisy-chaining to another sub if desired.

When driven by the LFE signal, the sub's contouring facilities are bypassed allowing crossover point, level, etc., to be determined by the HT processor settings.

I'm just not sure I understsnd what you mean when you say "the unit apparently senses the signal"? Do you mean that if you send the REL a line level LFE signal, it knows to stop reading the high level 2-channel signal? Cool, (I guess,) but you wouldnt need to worry about it being able to do that, if you just hooked the sub up with all line level feeds -- which as I mentioned earlier is best for sonics IMO (i.e. not passing the speaker signal for the main speakers through the sub.)
Ruark sub allows you to do 2 channel line level and LFE at the same time and has two gain controls, one for each input.
I'm not really sure about your question, but in subwooferdom two is better than one. Never heard negative experiences with two rather than one sub. This guarantees you a balanced stereo bass. I used one sub for years 'til I switched to two, from Audiogon suggestions. I was released. As was my system. peace, warren
Not sure why all subs do not work this way, but suspect it is a cost issue. The speaker level inputs on REL go into a switch selectable filter. Purpose is to fine tune the integration of speakers and room with the sub. It is not really a crossover, as the filter has no effect on what is sent to you main L/R speakers. And then the REL sub mixes LFE and speaker level.

In any case, it works well!
With REL subs, the speaker (high-level) input is the
PREFERRED method. It integrates better than with
low level signal inputs.

I have two REL Strata III subs which I use with both my
home theater system (low level input) and with my two
channel stereo system (high level input). They are
excellent and integrate seamlessly with my Magnepan
Just my opinion of course, but adding two more (mechanical) electrical connections and another pair of speaker cables between my amp and my main speakers just doesn't say "high end audio" to me. It's OK for a modest HT system, but at best a compromised result for 2-channel audio.

Then you misunderstand how a REL is connected at speaker-level.

With the REL, the sub is connected in parallel with the main speakers. It presents such a high impedence (100K Ohms, I believe) that it doesn't significantly affect the impedence "seen" by the amplifer. The speakers and the sub are both connected to the speaker terminals on the amp.
Nrenter, what you describe is technically the same circuit as I describe (except tied together at the amp instead of at the sub) And it's a little better, yes, for the same reason bi-wiring can be. But with the scheme you describe, you could really be buying lots of speaker cable!

Either way, the sub is sampling the amp output through a filter circuit of it's own. I guess that's OK, but being the stickler for cleanliness and simplicity that I am, I insist the sub have its own direct line-level feed out of the preamp.
Audio Concepts makes two models, The Force and The Titan,
that have all the inputs that you mention.
Sorry, Nsgarch. I thought you were implying that the signal was rolled-off (via a low-pass filter in the sub) before being sent to the main speakers. As you know (but for those who may not) this is not the case with the REL. The full bandwidth signal is sent to the main speakers, and a "sampling" of the signal (via the 100K Ohm impedence of the sub) is sent to the REL to be low-pass filtered and amplified by the internal sub amp. The REL is then adjusted in terms of amplitude (volume) and crossover frequency to integrate with the natural low-end rolloff of the main speakers. The REL doesn't use another set of speaker cables (although you could make a Neutrik-terminated cable out of a speaker cable). A supplied cable is included with the sub (but you can find reasonably-priced aftermarket cables, too).
REL Strata III have another advantage in the sense that they are sealed enclosures which integrates well with any speaker in the chain. I use it with the LS3/5a as well as Kef Reference Two, both totally different speakers yet the REL seamlessly integrates with both and sounds superb.

I reviewed it earlier at A'gon for those who like to read it:
I like the way these sound.

Can someone describe this Neutrik connector is detail? How many connections? You just slip it under the amps speaker outs on either the L or R channel? Can you use two subs? It does sound like something that might cause a different set of tranference conditions in that channel possibly negating big buck cables. Thanks for all the unput!
Why not get an Outlaw ICBM? It lets you combine and balance LFE and managed bass from any/all channels with any sub.


Here is what the REL setup states about the Neutrik connector:


High-level connection, using the enclosed cable with the Neutrik Speakon connector, is always the first choice. By connecting to the amplifier’s speaker outputs the sonic signature of the entire amplification chain is folded into the signal for the sub, thereby keeping timing and timbre cues consistent. In other words, the signal sent to the REL is exactly the same signal sent to the speakers, allowing for seamless integration. This connection can be made without affecting the performance of the amplifier because the sub’s amplifier input impedance is 100,000 ohms. This scheme also avoids adding any detrimental effects by not interposing any additional electronics into the amplification chain.
• The standard high level hook up procedure is: attach the red wire to the amplifier’s right positive speaker output terminal; attach the yellow wire to the amplifier’s left positive speaker output terminal; attach the black wire to which ever of the amplifier’s ground output terminals is convenient; plug the Speakon connector into the sub’s high level input.
• For differential amplifiers using one sub, simply use the standard connecting scheme with the exception of connecting ground to chassis ground, not to speaker output ground, and then connecting into the high level input (Hi Input or Unbal Hi Input on Stentor III and Studio III).
• For differential amplifiers using two subs for each channel: connect red to positive; yellow to negative; and black to chassis ground; plug the Speakon into the balanced high level input (Bal Hi Input).

Low-level connection, RCA inputs (or XLR on some models), is always an option, should high-level connection not be possible, or in a theater system where both high-level and low-level connection should be used. When connecting to the low level inputs, connect a single RCA cable to the 0dB RCA jack. Additional gain can be achieved by connecting to the +12dB input. If you are connecting two channels of stereo output from a pre-amplifier, simply use a high-quality y-adaptor to sum the two signals together.


If you want to know the types of connectors, take a look at the link provided

Hope this helps :)
Here is a picture of a aftermarket cable offered by Signal Cable - A picture is worth a thousand words.
I thought the Neutrik was something other than an XLR and I thought it was used at the amps instead of the sub, now it all makes sense. I understand the REL's are highly musical, do the 12" REL's have the low extension and amplitude for HT? Thanks all!
Neutrik makes all kinds of connectors. XLR is only one of hundreds of types they manufacture.