Hellow fellow Outlaws:

The 990 has two preamp subwoofer connections. I want to know from you who use twin subs what the different is from 1 to 2 subs?

Do you feel the SQ is better, worse, no change? How would you describe this setup?

Me, I m waiting for the next 990 preamp?

Liz

I have two subs for a few reasons:

1. Large room and 7 surrounds to keep up with.
2. Less room interaction. Well, probably.
3. It looks better (symetrical). To me anyway.

SQ? One could argue that two drivers have to work half as hard and therefore distortion is lower. I don't know how much difference that really makes from 20 hz to 60 hz.

I know this is not the technical answer you were looking for but maybe someone else will chime in.

I'll be on the pre-order list for the next 990!

Rick

With my original setup I had the Kef 107's in the front corners and the LFM1+ to the right of the seating position. However, I wasn't happy with the sound for a couple of reasons:

1. During certain movie scenes it sounded like I was overdriving the LFM1+ and
2. I could hear some directionality on the low frequency sound and there was a "hole" in the response to my left side.

Adding the two LFM1 EX to the system I learned that problem one was actually a resonance in a glass fronted cabinet adjacent to the subwoofer.

Moving the LFM1+ to the front of the room and placing the two LFM1 EX to the sides of the listening area solved problem two. The LFM1+ will eventually go somewhere else, either resold or moved to another room.

In answer to how it's connected; there's a Y adapter hanging off one of the two subwoofer unbalanced outputs on the 990, with the third sub connected to the other unbalanced output.

On music the bass goes deeper than I imagined. I though that I'd heard all the low frequency on Pink Floyd's _Dark Side of the Moon_ with the Kef 107's (flat to 21 Hz, off 3db at 17 Hz) but with the subwoofers I heard new notes.

With the volume up on movies I feel the furniture shake under me.

Life is good.

I have two subwoofers because:
a) I have a large room (20X23 with high vaulted ceilings), and
b) I have openings to other rooms at each corner. Not a great room to trap the bass. Lots of "leakage".

I have the subwoofers set up next to each speaker but that is probably not the best set up. Better to have each subwoofer 90 degrees out from each other.

I think I will probaly get the SMS1 bass room correction unit in a year or so. That unit will should smooth out the bass response. I am running DefTec BP 20's BP2000 CLR, BPVX and BP2's from the 990 and 770o.

I'm re-posting something which I originally posted here a few years ago. It details the benefits of using two subs in stereo, with their ability to recreate low frequency ambience cues (as opposed to directionality) - Altec


I have used my subwoofers in "stereo" for years. Read the following and see if you think you might get some benefit from this setup. To do it, all you need is two powered subwoofers with internal line level crossovers, and two extra interconnects.

While it is true that low bass is in theory non directional, the way that bass mixes in the room is not. An example - suppose that you have a group of performers on a stage and they are being recorded by two or three omni directional microphones in front about 15 feet away, which is a common technique. Now say you have someone playing a bass drum or string bass on the extreme left of the stage. The sound of that instrument will reach the left microphone earlier than the right microphone. Considering the frequency of the instruments will be be around 30 Hz in the case of the bass drum and 40 Hz in the case of the bass, the delay in the sound reaching the left and right microphones will be as much as half a wavelength. If you were to play this with a single subwoofer, or two subs with the bass between the channels electronically summed by the crossover as it is when you use the "sub/LFE" output on your pre/pro, this acoustic delay would simply cause peaks and dips in the response of the bass from that instrument. However, if you use stereo subs and are hearing ture stereo bass, this delay between the sound reaching the left and right microphones is heard as natural acoustic mixing of the bass frequencies from those instruments in the listening room, just as it did in the original recording venue. The way the bass mixes in the room is natural, acoustic, and dynamic over time.

As an example of another real-world benefit of stereo subs located next to the main left and right speakers, consider the following example. You have your single subwoofer connected to the "subwoofer/LFE output of your pre/pro, and the sub is located next to your couch, and you have it crossed over at 80Hz (in other words, a pretty conventional arrangement). The distance from your listening position to the mains is 10 feet (the sub is 10 feet from your mains). You play a studio recording that has a bass player coming from the right speaker. He plays an open "E" string. Guess what? The fundamental frequency of that string (about 40Hz) will come from the subwoofer next to you. The second harmonic at around 80Hz will come from both your sub and your main speakers. The 3rd harmonic (and above) of the bass will come exclusively from your mains. As you can imagine, this plays absolute havoc with the harmonic presentation and structure and of the instrument! The effect is of the same type, if not to the same degree, of taking the tweeter out of your speaker cabinets and relocating them a couple feet away. Fundamental frequencies coming from one place, and the harmonics coming from another. The closer the notes being played are to the bass crossover frequency, the worse this disembodiment of the fundamental from it's harmonics will be, as the phase difference between the two will be greater due to the higher frequency. Adjusting the "phase" control of your subwoofer will not correct this: it only corrects for one specific frequency, that of the crossover, and musicians hate being restricted to playing only one note (at least good ones!).

Electronics designers take great pains to ensure that all the frequencies in an amplifer (especially at the low end) are amplified with a minimum of phase shift (this is the reason for DC coupling) - Why mess this up if you don't have to?

I notice an increase in sense of "air" and "realism" on almost all recordings that have live performers, even studio recordings. While low bass cannot be heard as "directional" in the traditional sense, the way the bass interacts as it mixes acoustically in the listening room certainly can be sensed and felt as added realism, and the filling in of that dimension that you are in the space where the recording was made. In addition, sound effects that were recorded in stereo for movies will have their bass reproduced in stereo. This is especially apparent in city street scenes when a bus or train passes. It just sounds more "real" as a result of the way the bass mixes in the room, just like it would if you were there. This benefit wil also be apparent when playing multi-channel discs like SACD and DVD-A, as the main left and right channels will give this added realism from the natural acoustic mixing of the low bass.

This setup is completely transparent to HT, multi-channel, and stereo playback, as anything you throw at it will have the bass reproduced correctly, regardless of format. No more fooling around with the logisitics of what to do with the subwoofer when playing SACD/DVD-A - the bass just reproduces seamlessly.
And best of all, if you have the two subs and extra interconnects, doing this costs nothing.

The ".1" channel is a convention that came from the movie industry, and had no precedent in the music recording industry. It works for movies since in a large theater, very few people are in the "sweet spot", so a mono LFE track is a reasonable compromise.

The ".1" track is a bad fit for music however. Forcing the "movie" model for speaker configuration on a system playing music where a significant number of people are in the "sweet spot" does not work well - it's a kludge in my opinion.

You're basically thinking of your main speakers/subs as _very_ extended full range speakers that can take the demands of film/HT, while at the same time being optimal for music. The LFE track in movies is simply being routed as a mono signal to both of your mains, where it ends up in both of your subs, just the same way it would be if your subs were connected conventionally to your pre/pro with a "Y" adapter. When playing music (either stereo or multi-channel SACD/DVD-A), the entire music spectrum, including the bass, is in stereo, and coming from where it should be: next to (or part of) your mains. One of the results is a cleaner, more coherent and focused soundstage. I've also noticed a heightened sense of realism, and of feeling I'm in the recording venue. Even hearing the low frequency content of the air conditioning rumble and "room tone" that exists in all large spaces in stereo rather than mono enhances the sense of realism. A side benefit is that in movies, you will hear the extremely low frequency content of stereo sound effects (like street scenes with busses and trains etc) that reside in the main left and right speakers in stereo - something that you won't hear in a movie theater, or even on a movie dubbing stage since the mains in these venues only respond down to around 40Hz.


If you have to use a single subwoofer for whatever reasons, at least take into consideration the above and place the sub as close to the mains as possible. This is still a compromise however, since a single sub is still a significant distance from the mains.

While it is true that as the frequency of sound goes down, the ability to locate the source diminishes, but there are a lot of other things to take into consideration. It's just not as simple as "bass is omni-directional so it doesn't matter where you put the sub"!


To configure your system to take advantage of stereo bass, do the following:

First of all, move one subwoofer as close as possible to your main front left speaker. Move the other subwoofer as close as possible to your main front right speaker.

In your preamp�s speaker setup menu, set your main left and right front speakers to "Large". Set the subwoofer to "Off". Set your center and surrounds to "small" or "large" depending on their size. Most setups use the "small" speaker setting.

Disconnect the subwoofers from the LFE/Subwoofer output of your preamp. Run an interconnect from the main left and right outputs of the preamp to the "line input" of each subwoofer � the left out of the preamp to the left subwoofer, and the right output to the right subwoofer. Run an interconnect from the "line output" of your left subwoofer to the input of your left channel power amplifier. Run the right subwoofer�s "line output" to the input of your right channel power amplifier.

Set the crossover frequency of both of your subwoofers to the crossover frequency you used previously in your preamp. You will probably need to re-adjust the level controls of your subwoofers.

Hey there :-)

I am using my old Tube preamp with MULLARD tubes! I have a audio switch box so I can go between the tube preamp for CDs and the Outlaw 1070 as the HT Preamp to my Anthem Amp.

This tube preamp was modified by someone who used to work at the company and with the mullard tubes (7DJ8) the SQ is such much more to my liking.

The tube preamp has a 2nd set of outputs and I am thinking about getting a 2nd sub. That will allow me to get the full range (mains and sub) for CDs and I can also still get all channels for everything else.

I had a buddy install two Alps Black Beauty Mono pots years ago. The output is way to high and on Friday, he will help me place a shunt 20K attenuater.

I am going to wnat the next 990 Preamp and I hope that has two sub outs?

By using two sub outs to either one sub or two, do you think the SQ is better than just one and why?

Thanks in Advance.

Two sub outputs only provides a sound quality benefit over one output if the subs can be operated in a stereo mode, allowing a setup similar to what Altec describes (gotta love the classic Altec "stereo sub" concept). The 990's two sub outputs are functionally identical to the 1070's mono sub output, a splitter cable, and a couple extra dB of sub trim in the 1070's menu.

Currently, I also run ‘stereo’ subs, two of the same make/model, facilitated by an Outlaw ICBM between pre/pro and power amp.

There was a time I had only one sub. After a few years I tried ‘stereo’ subs. When properly set up, the difference for HT and commercially multi-track mixed-down music was marginally better, probably just in the way bass coverage spread throughout the room – I imagine no different than with twin mono subs. Where I do have the impression of something different that makes me smile a bit more when I hear it is with the playback of 'natural live sound' recordings, either stereo or SACD. I can't say with absolute certainty that my expectations don’t influence the way I experience the result of the stereo sub technique, but if you have the ability to try things three ways – single mono sub, dual mono subs, and stereo subs – I’d say give it a try and see what you think. Some folks advocate an additional sub to separate LFE duties from the low frequencies of the full-range channels, but I’ve never tried two subs set up that way, nor have I tried stereo subs with a third sub for LFE only.

Two Each His or Her Own.

Stereo Subs (before): For the past two years, my system consisted two 15" Def Tech subs, which were paired (with speaker level inputs) with the Right and Left front speakers (Outlaw 990 set to Large), resulting in a full range stereo mode configuration. The “LFE Only” signal was sent to third Velodyne sub. I was very pleased with the balance and tonal quality for HT, and especially for high quality stereo and 5.1 channel recordings. While I have been using stereo parametric equalizers for the main L/R channels, I have been unable to attain the same control of frequencies under 60 Hz compared to the new Velodyne Subwoofer Management System (SMS).

Dual Mono Subs (after): Three weeks ago I made the plunge for 2 LFM-1 EX’s and the SMS-1 Parametric Equalizer. The SMS-1 does not lend itself to a stereo sub set-up, and the crossover in the 990 only provides a summed mono signal sub output. To achieve true stereo subwoofer output would require a separate stereo crossover between the 990 Pre-Processor line-level outputs (at large, full range signal) and two SMS-1’s. (Yes, you can use speaker level connections if you dare) In any event, it would be very complicated. At this time, I cannot justify the effort and expense of achieving a true stereo sub configuration, and believe that the benefits of the SMS-1 to be significantly more important.

Analysis: The SMS-1 is both a powerful analysis tool, and room/speaker correction device. Using the crossover network of the 990 (mains set to Small with 60Hz XO), the SMS-1 is easy to configure and set up. It was possible to compare the performance of one versus two subs easily, with the test microphone placed at various positions in the room. I found that two subs were significantly better for three reasons; 1) Much larger sweet spot, 2) More consistent sound level throughout the frequency range of the subs and 3) deeper base extension. One LFM-1 EX had a -2dB point of 17 Hz (one port plugged), whereas two subs were solid down to 15 Hz, which was the limit of the test trace. The controls and frequency response measurements are displayed through one of the 990’s audio/video source inputs.

Other Observations: My LFE channel is now also routed through both subs, so I no longer have a separate third sub dedicated to the LFE channel. I have not found any compression or other adverse affects in combining the LFE signal with the crossover signals from multi-channel recordings. As mentioned by others, I believe it is a good idea to place the subs close to the main L/R speakers or at least at a similar distance to the main listening position to preserve phase alignment of these long sound waves (a 40Hz wave is approx 25 feet long).

Testimonial...
In A/B testing, comparing the Def Tech subs vs. the Outlaw LFM-1 EX’s, there was an astonishing improvement, even before dialing in the EQ. The tonal balance, smoothness, and power of these Outlaw beasts (coupled with the SMS-1), allow for music to be played at preposterous dB levels without sounding “loud”. Distortion is the enemy of volume, and Outlaws.
Thanks Outlaws.

My experience is reflected in much of AGAssarsson response.

I'd just like to add that it's really difficult, if not impossible, to get a sub(s) to sound its best in most rooms without some EQ. With 2 subs EQ'ed the low frequencies really envelope you and give a better sense of the total sound field enveloping you as well. It's really an uncanny experience.
The subs do not have to be in the same spot or near the mains for accurate phase response in multichannel, that's what the speaker distance setting is for.
Also, running 2 subs will generally provide bass with less distortion, as you don't have to push 2 as hard as 1 to get the same bass level. Less demanding on the sub amps as well.

I recommend trying 2 subs. With some patience, no, a lot of patience, they can make a dramatic difference in providing clean bass and a more 3D soundstage.

There is an excellent articel on the web by Dr. Harmon of Harmon International that describes via computer modeling the effects of subs, from one to I think 400! in a room. They concluded that 4 are ideal but 2 get you pretty close to ideal.It's worth a read.