background image

SV Subwoofers 

Page 12 

Subsonic Filter and Port Tuning 

 

Y

our new PC-Ultra subwoofer not only comes 

with our “Tri-Power” port flares, but  

custom port 

plugs

 and 

variable subsonic filter 

which allow  

your sub to be “tuned” to even lower frequencies 
than its stock configuration.  For most people and 
most rooms, your SVS is already configured for 
the best blend of extension (how deep/low your sub goes) and output (how loud it 
gets at a variety of bass frequencies).  However, we know that bass is a very personal 
taste and no two rooms will react exactly the same with any subwoofer.  So we in-
clude a custom “port plug” that, when inserted into a port, allows you the user to 
experiment with a substantially lower “tune”.   
 

A

s with all such devices, there are compromises when tuning a sub lower.  Installing 

a port block takes some capacity from upper reaches of bass, installing 

two 

port 

blocks naturally limits upper bass response even more.  So while you will indeed get 
more bass down low (where DVD and music bass is more rare, but quite exciting!), 
you’ll sacrifice total output capacity above the stock tuning point of the sub (where 
bass is more common).  You should decide if the effect is pleasing on the sorts of 
movies and music you enjoy.   
 

H

ow to do it?  To insert a port plug, simply squeeze the foam on one end and press 

the plug into a port flare until it is about 1” lower than the edge of the surface of the 
sub.  You can remove the plug by inserting your fingertips into the port flare and 
squeezing and pulling on the foam plug at the same time.  Be sure to select the sub-
sonic filter point on the back of your PC-Ultra amp which coincides correctly  with 
your new “tuning point”.   

NOTE

: We strongly recommend you do 

NOT

 run a 

lower subsonic filter point than your port plug configuration would dictate — espe-
cially if you are running the subwoofer at high sound pressure levels!  Moderate 
levels are doubly important if you put the subsonic filter into “

12hz

” mode 

(essentially turning off this key limiter).  This simple table indicates the settings you 
should use in setting up your sub blockers and the subsonic filter knob. 

 
 
 
 
 
 
 
 
 

L

ook to the next page for a computer simulated response chart showing the reduc-

tion of upper bass when adding one, and then two port-blockers to your SVS (along 
with addition woofer excursion needed to keep up with the lower frequencies).  The 
bottom line?  Many customers feel the slight loss in upper bass output to be insig-
nificant compared to the deeper response the port block gives.  We let you decide

.

 

PC-Ultra Tuning Chart

 

Subsonic Filter Knob 

Stock tune (no ports blocked)

 

20Hz

 

With one port-blocked

 

16Hz

 

With 

two 

ports-blocked

 

12Hz

 

Summary of Contents for PC-Ultra

Page 1: ...ages 4 7 Setup integration and calibration Page 7 8 Powered cylinder amp features Pages 9 11 Parametric equalizer PEQ Pages 12 13 Variable tuning Pages 14 15 Bass demos Last update 27 January 2004 OWN...

Page 2: ...ully tuned in our labs by bass authority and Sub human Tom Vodhanel You re unlikely to have heard or felt bass like this before unless it was in a top notch commercial movie theater or high end high c...

Page 3: ...ing driver Coupled with our unique base plates which minimize driver reactive forces you ll find our subs can take a tremendous amount of power and remain rock solid Compliant foam rubber feet on our...

Page 4: ...s corners The upright configuration of SV Subwoofers makes this easy Whether you put the sub in front or to the rear of your seating area makes surprisingly little difference Deep home theater bass li...

Page 5: ...refresh on the proce dures to do this Generally this requires ensuring the receiver s test tones or a special test disk like Video Essentials or Avia plays back at the same volume from each of your sy...

Page 6: ...r receiver processor master vol ume is set at 00 dB or some other easy to remember reference level Finally ensure your SVS s volume control is set no more than 1 4 to 1 3rd up at first It s also criti...

Page 7: ......

Page 8: ...he switch in the Auto position your subwoofer will sense that a DVD or CD etc has begun and switch on immediately the hard power switch mentioned below must be on naturally A few minutes after a movie...

Page 9: ...THIS CONTROL Set the LEVEL control in the Parametric EQ feature group ing until it stops on MIN thus ensuring you do not inadvertently cause poor frequency response until such time as you properly co...

Page 10: ...energy requiring several times the amplifier power to achieve You can see then how critical the below chart is if you are using your PEQ to even out or flatten the room response of your bass Add the...

Page 11: ...40Hz Why If we used 40Hz as our center frequency and 50Hz as our high point cutoff we would only attenuate the curve down to 30Hz This will leave a small bump in response near 25Hz because the correct...

Page 12: ...y How to do it To insert a port plug simply squeeze the foam on one end and press the plug into a port flare until it is about 1 lower than the edge of the surface of the sub You can remove the plug b...

Page 13: ...SVS PC Ultra tuning chart...

Page 14: ...ic this sub is itching to show off Chapter stops for DVDs are shown with movie time in hours min utes seconds What are you waiting for Just hit PLAY The Iron Giant Great family animation with SERIOUS...

Page 15: ...dern sci fi horror classic this one rocks from intro to final scene 1 Ship drop Scene 9 41 20 2 Awakenings Scene 15 1 12 52 Apocalypse Now Making This Vietnam war movie Francis Ford Copolla nearly wen...

Page 16: ...rials and workmanship SVS will repair or replace any item at its discretion and return to the customer as soon as possible Naturally this warranty does not cover any product subjected to misuse abuse...

Reviews: