Greetings,

Recently I upgraded my stereo to an HT system that included an Outlaw
1050 and a Boston Acoustics System 9000II. Over the past month I have
been trying to sort out what configuration of these two systems sounds
best to me. The results surprised me and I thought I would share them.

1. The Instructions

Right off the bat Outlaw and BA differed on the "preferred" configuration
and setup. Outlaw counselled that most speakers should be set to
"small" and the subwoofer should have it's xover set to provide the best
blend. BA suggested that the "preferred" configuration was to hook up
both the LFE output to their subwoofer AS WELL as speaker-level inputs
from the L/R front speakers. They suggested setting the subwoofer to ON
and the L/R front speakers to "large".

2. What I Did

As the Outlaw instructions struck me as better justified, I began
with them. I found out from BA which of the two line-level inputs was
unfiltered and connected that to the LFE-output jack on the Outlaw. All
speakers were set to "small" and I selected an Xover setting of 120Hz
as this represented the lowest flat (+/-3db) frequency that could be
reproduced by the least capable of the satellites.

The system sounded pretty good but I noticed a couple of troubling
things. The front satellites sounded awfully thin to me. Worse, the
subwoofer produced sounds that were both easily localizable and terribly
boomy. By lowering the subwoofer volume I could control the boominess
but to eliminate it altogether the subwoofer was virtually silent.

I messed around with the Xover setting. Increasing it to 150Hz made the
satellites sound downright tinny to me. Decreasing it to 100Hz or 80Hz
improved the satellites' performance but resulted in an audible mid to
high bass gap.

One day I set the Xover back to 120Hz and tried jacking the LFE output
into the subwoofer's FILTERED input jack. This, surprisingly, improved
things. I was surprised because it violated a "first principle" I had
learned which is to avoid double-filtering.

Based upon this surprising turn of events, I decided to ask both Outlaw
and BA a bit more about the nature of their filtering networks.

3. What I learned

The 90pvII subwoofer that BA provides with the System 9000II has a fixed
fourth order low pass filter set to 120Hz. Outlaw uses a variable low
pass filter with a second order slope.

4. What I Did Next

Over this last weekend, I reconfigured the system based upon BA's original
proposal. Initially I assumed their recommendation was based upon the fact
that many low end receivers have fixed LPFs set to 100 or 80Hz. I left
the adjustable LPF on the Outlaw to 120Hz, wired speaker-level connectors
to both the L/R front satellites AND the subwoofer and also connected up
the LPF output to the (this time) unfiltered subwoofer input. I set the
front speakers to "large" in the Outlaw.

The sound was surprisingly improved. The subwoofer now behaved as it had
when I originally connected the line-level output to the filtered subwoofer
input. But in addition, the satellites sounded quite rich and blended
flawlessly with the subwoofer. The subwoofer authoritatively reinforced
the satellites and was never boomy or easily located in the room.

5. What I Think Happened

The BA 90pvII subwoofer is a "real" subwoofer (based upon their PV600
model) and really doesn't want to receive signal above 150Hz. I contrast
this with some of the mid-bass units (such as the ones Bose sells) that
are "happy" with frequencies in the 200Hz (and above) range. I believe
that above 100Hz, a typical 2nd order low-pass filter as is found in
the Outlaw is too shallow for subwoofers such as the BA 90pvII. I think
at medium and high volume levels, too much higher frequency signal is
leaking through. The BA folks chose a 4th order low-pass filter as the
internal filter for this subwoofer. By setting Outlaw Xover to 120Hz
and feeding it through the subwoofer's filtered input, I ended up with
a VERY steep filter curve at 120Hz. (Perhaps too steep). In any event,
it sufficiently attenuated the higher frequencies so that the subwoofer
could effectively ignore them and as a result sounded MUCH better.

As far as the satellites are concerned, if we assume that natural
rolloff of the midrange drivers is around 12db/octave (approximating
a 2nd order filter) below 120Hz, the additive effects of filtering all
less-then-120Hz frequencies in the outlaw produced an effective filtering
rate that was TOO steep and provided no opportunity for blending with
the subwoofer. By sending the entire frequency range to the satellites,
the whole system sounded much richer.

The two downsides to my current wiring scheme are that the Outlaw has
to work a little harder and I somewhat increase the risk of damage
by sending too much REALLY low frequencies to the little satellite
speakers. BA assures me the satellites can handle it. I am confident
that the Outlaw 1050 can handle it as well...

6. Conclusion

The configuration described above sounds very good to me. Perhaps my
theories are entirely wrong but I would encourage others with similar
systems (small satellites that aren't flat below 100Hz combined with
real subwoofers) to experiment....


-Andy

Excellent report, newman -- should be very useful for the Boston Acoustics users around here.

------------------
Gonk

Uh oh... good thing I'm done with school next week. Sounds like I have some tinkering to do! Thanks for the report!

Fascinating! And potentially very usefull! When my 950 arrives, I'll be moving the 1050 from the Home Theater up to the Great Room & I suspect I'll be looking for a small sat/sub combo for it.

Thanks!

------------------
pat----

email: pat@sklenar.info ---===--- home page: Grumpy's Lair

newman
Nice. Very nice! I have the 9000ii's also and had noticed the boominess as well. I also will be doing some tinkering in the coming days. By the way, which LFE input is the filtered one?

Oops. I just came across your post from the 8th which answered my question.

"From LFE output" = unfiltered
"From Sub output" = filtered

Thanks

Well, I couldn't wait. I upgraded my satellite service from Dish Network to DirecTV. Since I now had a digital output for my audio from the satellite, I bought one of Outlaw's PDO cables. Very nice and packaged quite well. I'm glad I gave them my thirty bucks instead of Sears. I think I got a lot more for my money.

Anyway, the point of all this is now I have to pull out that HEAVY entertainment center so I took the opportunity to hook up my System 9000's sub to both the LFE and to the L/R speaker level inputs. I then set my L/R's to large. WOW! Thank you, newman! Much fuller sound. I'm very impressed with the improvement in the sound of my Barenaked Ladies CD. Can't wait 'til this weekend when I'll really get the chance to play!

I was a little concerned about sending a "large" signal to the satellites, but since BA told newman not to worry, I guess I won't either.

Thanks again, I can't believe the improvement in sound!