Setup and Operation
Placement. The manual consists of a double-sided sheet of paper.
Unfortunately, it does not contain any useful information about speaker
placement for the Infrasub-18. I suppose that your dealer would be able to
help determine the best location given your specific system. If you are like
me then you have read several conflicting opinions on where a single subwoofer
should be placed in a rectangular room. I started off with the sub in the
front left corner. I ended up with it 1' away from the front and 8-10"
away from the sidewalls near the right corner next to my equipment rack.
II. Hookup Choice #1. Bag End recommends connecting the output from
the front channels of a preamplifier (if available) directly to the subwoofer,
and then utilizing the high pass outputs back into the main amplifier. The
subwoofer itself has no crossover adjustment. If you don't run a cable back to
the main amp and make connections in this manner, then the bass information
from the Infrasub-18 and the main speakers will overlap. This could possibly
entail very long cable runs to and from the subwoofer, and could get expensive
depending on the quality of cable used. For Part I of the review I connected a
pair of Audioquest cables to the left and right inputs on the subwoofer and
used a pair of Music Metre cables back to the amplifier. When I disconnected
the sub for comparison I used the Audioquest cables directly into the
III. Hookup Choice #2. Another possibility would involve connecting
the subwoofer output from a surround unit to a single input on the Bag End
subwoofer. This means that the subwoofer could receive a smaller bandwidth,
and allow the main speakers to receive lower bass information. This connection
would normally allow a selectable high pass crossover for the main speakers,
and an adjustable low pass crossover for the subwoofer depending on how
flexible the surround processor/ preamp is. This was the setup used for Part
II of the review.
IV. Adjustment. There are only two controls on the back of the
subwoofer. One is the level adjustment, and the other is the phase switch. I
adjusted the level by ear with the use of the Stereophile Test CD #2,
tracks 3 and 16. I also made use of the HFN/RR Test Disc II, tracks
43-48. After some crude adjustments I listened to a few recordings to make
sure the level was appropriate. With a 17 Hz tone from the test disc I had a
slight rattle in the room from who knows where. At 20 Hz my rack was vibrating
and I could feel a throb in the room. At 31.5 Hz there was even more output
and the floor was shaking. At 50 Hz there was significant output and in my
room this was the most output across the frequency range based on placement of
the subwoofer and my listening position. I played with the phase but there was
more output in the 0 degree setting (as opposed to the 180 degree setting), so
I left it there.
V. Finish. Normally I don't comment on the look of the products I
receive unless the look is closely related to the application or claim of the
product itself. I felt it necessary to mention that the vinyl covering was
already starting to peel in the back left corner of the subwoofer. The
Infrasub-18 is offered in a few wood finishes that would push the price of the
subwoofer to over $2000. It may be worthwhile however, if the subwoofer is to
be in plain view alongside nicer furnishings. From a distance it was not a
problem for me, but I usually expect a little more from a speaker in this
This section contains comparisons between the output of my stereo preamp
into the Bag End subwoofer and out to the amplifier, and direct connections
bypassing the subwoofer and running the speakers full-range.
I put on R. Strauss's "Intro to Also Sprach Zarathustra" and J.
Strauss "Banditen Galop" from the Telarc Sampler Volume 3. These
pieces have extended deep bass and good dynamic range. I found the bass to be
deep and taut, well integrated with the Revel F30's, and dynamics were
excellent. Everything sounded very good from the start except for whatever it
was that was rattling in my living room. I moved a few things around and got
the rattling down to a minimum. I felt the urge to play everything really
loud. My neighbors might not have been so happy about it though-it was 11:30
(2) Next I listened to track 1 from Donald Fagen's Nightfly. I felt that
the bass was somewhat localizable. It seemed that the crossover might be the
reason, but with this connection there was no way to check this. See Part II
for further details. Overall I was very impressed with the quality otherwise.
(3) From the Diva CD I listened to Peggy Lee singing "Fever."
Bass was clearly emanating from the center of the main speakers on this cut.
Unfortunately, Peggy wasn't the only one with a fever-this time it was my
fireplace cover (which is metal and glass) vibrating away. By opening it
partially I was able to eliminate the rattling. I began to realize how much
care must be taken in what goes into a room with a subwoofer capable of the
quantity of low bass that the Bag End offers.
(4) After listening for a few days, I began with the critical listening
sessions. I wanted to determine if and how much signal loss might be present
as a result of my connecting the subwoofer between the preamplifier and
amplifier. I put on track 5 from Elton John's Tumbleweed Connection on MFSL.
With the subwoofer in the system the low bass had better definition and
trailed off more naturally. There appeared to be a slight reduction in high
frequencies, and everything seemed just a bit toned down. I checked levels
with and without to make sure that the subwoofer wasn't lowering the signal
level. I was surprised to find out just the opposite. It seems that when the
subwoofer was connecting in between the amplifier and preamplifier, the level
was slightly increased. I was able to adjust the volume to compensate. The
Revels have a bit of extension in the highs that may not be entirely accurate,
so it tended to be easier to listen to the system with the Bag End in the
system due to a shift in tonal balance. But without the subwoofer the
soundstage width increased and vocals became more natural and 3-D. The sound
was bigger and brighter, with a better sense of space. That there was a
reduction in bass goes without saying. Note: When I turned off the power on
the Infrasub, there was a loud thump. No harm was done, but it was quite
(5) I became more concerned about testing for the loss due to using the
internal crossover in the subwoofer. There was no doubt I was gaining an
improvement in low bass, in dynamic capability, and pure output, but at what
cost? I tried David "Fathead" Newman playing "Night of Nisan"
from Atlantic Jazz Flutes. With the subwoofer in the system I was tapping my
foot in time with the music and really enjoying myself. When I disconnected
the Bag End, the hiss on the recording became more apparent, there was a
reduction in low bass, and the sound was not quite as involving. However,
there was definitely a slight loss of transparency that occurred when the
subwoofer was connected between the amp and preamp. I couldn't determine if it
was due to the cables, but I'd guess it was not.
(6) I began to feel that I should check out some familiar recordings that I
know have deep bass content just to see how much improvement there was. I put
on tracks 1 and 2 from Pink Floyd's Dark Side of the Moon. I have never heard
bass this deep in my room before. It felt as if the big "heart" was
in the room beating away with the walls bending before it. When the throbbing
stopped, in came the mid bass. The bass power was almost scary. Without the
subwoofer in the system there was still a good amount of low bass (as the
Revels have 10" woofers already), but it was not room shaking. The output
level was lower and you could tell the speakers were working harder. The
speaker also sounded congested at a higher level. That could have been due to
overworking the amp. As I said before, with the Bag End in the system I could
definitely play music louder. Instrumentation did improve a bit without the
sub. I still go by my recommendation to connect the subwoofer outside of the
amp-preamp chain when using revealing equipment and speakers.
This section contains listening tests using the internal crossover in the
Meridian 568 preamp set to 60 Hz for both the high and low pass signals to the
main speakers as well as the Infrasub-18. The Meridian not only offers
adjustable crossover frequency in 1 Hz steps, but also allows different
adjustments for the high and low pass. In addition, there is a separate
subwoofer level depending on which surround/ processing mode is being used
(i.e. a setting for stereo, a different setting for Dolby Digital, etc.)
(1) I listened to the "1812" Overture by Tchaikovsky on Telarc
from 12 minutes to the end. With the direct connection to the main amp I felt
secure that I was not losing a bit of information in the upper ranges while
the subwoofer easily handled all the low bass information. Since the range of
the subwoofer was narrower, setting the level on it was not as critical as
before. Also, I gave myself a way to adjust the level electronically whereas
before I could only adjust the level from the back of the subwoofer itself.
Since I had such a wide range of adjustability on the Meridian, I could have
chosen just about any crossover point. I would think that a standard 80 Hz
setting would work fine with just about any speakers and this is a very common
setting on almost every surround unit I've ever used. I would think that the
people that would be considering the purchase of this subwoofer probably have
sophisticated enough equipment that would allow this kind of flexibility. If
you are stuck with a stereo setup that does not allow crossover adjustment,
and you are not interested in getting an electronic crossover, then it would
be worth your while to make sure that there is not an unacceptable amount of
loss of resolution when using the internal crossover in the subwoofer.
(2) With track 3 and 4 from Moby's Play, I was certain that I had found the
setup I liked. I was hearing everything on the recording with better bass than
ever before. When the low bass wasn't present then the Bag End was silent, and
when the bass came in it was really there! I like the fact that the Bag End
had a slightly more restricting frequency response, because integration with
the rest of the system was even better than before.
(3) One song that really has a good bass line is track 8 from Me' Shell
Ndegeocello's Peace Beyond Passion. I got super clean upper bass coming out of
the Revels, the mid bass overlapped nicely, and the low bass just shook and
thudded exactly as I wanted it to. And like before the bass level wasn't that
critical. Whether I moved it up or down a little it still blended extremely
(4) I decided I should revisit the Donald Fagen track off the Nightfly
album mentioned in Part I-(2). The bass level seemed lower at first, but then
I realized it was more defined and I was hearing it from between the speakers
and not over in the corner. This seemed to solve the problem with being able
to localize the bass.
(5) I tried Cannonball Adderley's Somethin' Else on MFSL, track 1.
This recording doesn't have all that much low bass, but there is some midbass,
and the Infrasub-18 was doing a nice job and not coloring the sound. In fact,
you'd think that it wasn't even playing-at first I even had my doubts! So I
turned off the main amp and listened to just the base line on the Bag End. I
could hear the individual bass notes and the sound climbing up and down in
frequency as well as shifts in volume and sustain. Everything was working
(6) Lastly I listened to Toccatta & Fugue in D by Bach and
Prokofiev's Romeo and Juliet (Montagues & Capulets) both from the Telarc
Sampler #1. I experimented as in (5) by turning the main amp on and off to
listen to the contribution made by the Bag End. With the organ piece, the bass
was so intense I could feel air moving about 2' away from the subwoofer. My
rack was shaking, as was the Bag End on the floor during certain moments in
the cut. The bass on the second piece was not as powerful as the first, but
was still presented very nicely.
When I first received the Bag End I felt like a little kid the first time
your parents leave you home alone and you feel free to play and have a good
time. This is how it all began. When most people think of 18" woofers
they probably imagine loud obnoxious car stereos booming down the street at
1:00 in the morning. Or maybe what they have in their mind is a big ugly box
with one-note bass. That is not the Infrasub-18. It produced bass-deep, tight,
clean, controlled bass is what came out of this subwoofer. I easily reached
the limit on my power amplifier before the subwoofer came even close to
When connected via the internal crossover and then to the main amplifier,
the Bag End integrated very well with my main speakers. There was a slight
loss in transparency with the subwoofer connected to my amp, but this was
eliminated with a direct connection from the subwoofer output of my preamp.
This is my only hesitation in recommending this sub, and it is a small one.
Only on a few recordings was there indications where the bass was coming from,
and this too was eliminated when the crossover frequency was lowered. With
more experimentation with placement it is possible I could have even better
performance, but I was more than happy with the quality of sound with the
subwoofer in the corner of my listening room. If you are in the market for
serious low bass, then this subwoofer is a must audition. For the quantity and
quality of bass produced, the Bag End is a very good value.
- Brian Bloom
Description and Specifications: 400 Watt 18" forward firing
sealed powered subwoofer. Input channels (RCA jacks) for left, center, and
right with high pass outputs at 12dB per octave (-6 db 95 Hz), one pair of
speaker level inputs, level adjustment, polarity +/- switch, detachable power
cord, and master on/off switch on back of unit. Rated frequency response is 8
- 95 Hz +/- 3dB. Built-In overload protection is provided to prevent damage
due to overdriving the sub. 23.5" H x 21.25" W x 18.25" D. 1
Equipment Used: VAC D/A converter MK II, PS Audio P600 power
generator, Philips CDC-935 transport, Meridian 568 Preamplifier, Krell KST-100
Amplifier, Audio Research LS-3B Preamplifier, Revel F-30 speakers, and
Audioquest, MIT, and Music Metre cables.
MSRP $1495 (black vinyl)
Bag End Loudspeakers
22272 Pepper Road
Barrington, Illinois 60010
Voice: (847) 382-4550
Fax: (847) 382-4551