In-Room Frequency Response: I placed the 850 SC in the front left corner of my 2,000 ft3 evaluation room, which is acoustically treated and bass-trapped.  I connected the software signal generator to an analog stereo input on the surround sound processor (SSP) and measured the combined frequency response of the mains speakers and subwoofer at the primary listening position.

For digital bass management, the main speakers were set to "Small" with a crossover frequency of 100 Hz.  The digital bass management circuit imposes a 2^nd order high pass filter on the speakers, and a 4^th order low pass filter on the subwoofer.  I set the low pass filter to 200 Hz, and the phase control to 0 degrees and adjusted the subwoofer distance setting in the SSP to obtain the best phase integration with the mains.   

The in-room frequency response of the Wide mode setting is 21 Hz - 100 Hz ± 3 dB, with only minor upper bass anomalies from room modes and the asymmetrical filter slopes in the SSP digital bass management circuit.  The gradual anechoic roll-off the 850 SC in the Wide mode setting, combined with the acoustic transfer function of the room (often referred to as "room gain"), results in a considerably improvement in deep extension compared to the anechoic response.

With Movies

I played several action-oriented DVDs, evaluating the 850 SC for mid-bass dynamics, audible artifacts (muddiness, cone cry, rattling), deep extension and output compression.  My overall subjective home theater ratings for the 850 SC are provided in the table below, with a rating of 5 being the best score:

Evaluation Criteria	Rating (1-5)	Summary Comments
Mid-Bass Dynamics	3.50	Muscular mid-bass output, with plenty of punch for a single 12" woofer in this size enclosure.
Audible Artifacts	3.00	Port chuffing is audible on any deep bass scenes which contain little or no masking content.  The tonal character becomes coarse when pushed hard, but it was impossible to bottom the subwoofer, indicating an effective amp limiter.
Deep Extension	4.00	Digs to 21 Hz in-room.  Anechoic roll-off is an excellent match for the acoustic transfer function of a mid-size room.
Deep-Bass Compression	3.00	Moderate compression of deep/loud bassy peaks was noted at high playback volumes.

Provided below are my listening notes and a few spectral frequency charts, from Munich in Dolby Digital 5.1.  These spectral color charts were electronically recorded directly from the DVD, and show where the deep bass occurs on a given passage, with dark red and pink colors being the highest amplitude.  These spectral charts were provided with the assistance of Patrick Lincoln.

To determine the maximum audibly clean output of the 850SC in my 2,000 ft3 evaluation room when playing select bassy passages from Munich, I increased the master volume until I noted audible artifacts (port chuffing, pitch changes, coarse/muddy texture) or a loss of dynamics and/or deep extension (indicating output compression).  Then I backed off until the master volume until an audibly clean and dynamic presentation was restored. Peak sound pressure levels were monitored at the listening position with a B&K SPL meter set to C-weighted Fast. 

Time Stamp	Audibly Clean Playback Limit	Maximum Playback Level
0:51:21	93 dB – onset of port chuffing.	101 dB – obvious port chuffing, pitch change, and limiter activity.

The Mossad agents realize an innocent girl is about to become collateral damage in one of their planning revenge bombings and they hurriedly take action to abort the mission.  This scene contains loud/deep bass used to build tension and provide a sense of dread.  There is very little midrange masking content in this scene, making it an excellent candidate for evaluating port chuffing, which occurred at a relatively low 93 dB.  Subjective deep extension was very good; the 850SC easily played the 22 Hz - 23 Hz peak, only failing to fully resolve the infrasonic content in the 14 Hz - 17 Hz region. 

 

Time Stamp	Audibly Clean Playback Limit	Maximum Playback Level
0:54:07	103 dB – onset of pitch change and worsening of tonal quality.	106 dB – coarse texture and compressed dynamics.

The detonation of the carefully planted telephone bomb marks the first big explosion in the movie.  There is plenty of masking noise in this scene, so port chuffing was never audible.  Tonal quality and dynamics were well preserved up to about 103 dB.  I was able to push another 3 dB higher before the onset of obvious overload and dynamic compression. 

Time Stamp	Audibly Clean Playback Limit	Maximum Playback Level
1:05:09	104 dB – onset of pitch change and a worsening of tonal quality.	107 dB – coarse texture and compressed dynamics.

The head Mossad agent signals for a remote bomb detonation by clicking off room lamp, thus snuffing out the life of another marked Palestinian terrorist.  This is easily the largest LFE hit in the entire movie, replete with strong infrasonic content and plenty of rolling mid and upper bass aftershocks.  The 850 SC missed the big hit at 14 Hz, but otherwise delivered a solid punch on this scene, handling the aftershocks particularly well.  This is another scene where midrange content will completely mask any port noise, so I listened for changes in pitch and tonal character to determine the maximum clean playback limit.

With Music

I evaluated the 850 SC on several music selections for balance, definition, pitch, coherence, and deep extension.  This subwoofer was a very pleasant surprise on music; it handled everything except pipe organ music with total aplomb, sounding completely natural and exhibiting outstanding rhythm and pace.  I attribute this excellent music performance to the superior transient response and phase characteristics, and the near-perfect match with the acoustic transfer function of the room with the resultant flat in-room frequency response.  My overall subjective music ratings are provided in the table below. 

Evaluation Criteria	Rating (1-5)	Summary Comments
Balance	4.50	Excellent octave-octave balance.
Definition	4.50	Superior mid-bass articulation.
Pitch	4.50	Pitch preservation is outstanding on all music at any reasonable playback level.
Coherence	4.50	Sounds tight and "stops on a dime" without any overhang and outstanding rhythm and pace.
Deep Extension	4.00	Adequate for all popular music, only lacking the 17 Hz extension required for pipe organ.

Provided below are some listening notes from a few CDs. 

 1) Heart Shaped World  – Chris Isaak, Reprise Records, 1989.  This vintage Isaak release remains one of my favorites for evaluating subwoofers. 

"Don't Make Me Dream About You" features Roland Salley's sassy and throbbing bass line. The 850 displayed excellent pitch, note changes were easy to follow, articulation was very good, and the overall octave-to-octave balance was excellent. 

"Wicked Game" finds drummer Kenney Dale Johnson co-anchoring with bassist Salley as the kick drum strikes synch with the start of each bass note.  The 850 made it easy to hear and differentiate each instrument and each kick drum strike sounded tight with no blurring or overhang. 

Johnson lets it all hang out on "In the Heat Of The Jungle", with a hard driving and syncopated drum line.  Each tom-tom strike sounded percussive and tight on the 850 SC, with realistic skin timbre and toe-tapping rhythm and pace.      

2) Brothers In Arms – Dire Straights, Warner Brothers 1985, 2005 Mercury Records High Resolution SACD German Import.  The stunning 20^th anniversary SACD edition of this landmark Dire Straights album restored my shaken faith in the high resolution music formats.  I specifically spun this disc to see how the 850 SC handled the hard striking and subterranean drum/synth sound effect featured in "The Man's Too Strong".  I was not disappointed; the 850 SC went deep and clean, with good foundation and presence in the room, signifying true low end response.    

3) Go! – Dexter Gordon, Blue Note (Capitol) Records, 1962, 1999.  Dexter was a jazz giant, and few classic jazz aficionados would disagree this is Gordon's finest album.  Bassist Butch Warren anchors Cheese Cake with perfect rhythm and lively bass lines.  The 850 SC filled in the bottom end without a hint of bloat and exhibiting good pitch, thus preserving the delicate timbre of the upright bass.

4) Flight Of The Cosmic Hippo - Bela Fleck & The Flecktones, Warner Brothers Records, 1991.  The title track features some interesting and unique 5-string fretless sliding bass guitar work.  The 850 SC effortlessly tracked the sliding bass scales, always maintaining good balance, definition, and pitch.

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