The Distinctive Sounds Between The SVS PC+ And PC-Ultra Drivers

Discussion in 'Speakers & Subwoofers' started by Ferdinand*T, Sep 7, 2004.

  1. Ferdinand*T

    Ferdinand*T Second Unit

    Joined:
    Nov 11, 2002
    Messages:
    284
    Likes Received:
    0
    Trophy Points:
    0
    Hey guys I'd like to get your opinions here. Now before I start, this is not one of those which sub should I get threads or anything like that. What I want to know is the distinction sound that each subwoofer puts out. I use to own a 20-39PCi and loved it but I wanted more power.

    Now I've done a little research and found that the difference between the PCi and PC-Plus is pretty big. Now my question is, is the sound from a PC-Plus compared to an Ultra that big a of differnce to make it worth the purchase over a PC-Ultra? I've heard a PC-Plus and I do agree it does sound better than an PCi. So that I'm certain.

    I see both PC+ and Ultra have the same 525 watt Bash amp so the SPL would be about the same. So now it comes down to the driver itself, the TV-12 and dB-12. Does the sound from the TV-12 that much better to make it worth spending the extra cash? For me it would be $367 extra. I've heard that the TV-12 has its own sound which people love, but is it that much of an improvement?

    I plan to place my order next month and I don't mind spending the money if I feel it is worth it. I just want to make sure.
     
  2. Tim Stumpf

    Tim Stumpf Stunt Coordinator

    Joined:
    Mar 3, 2004
    Messages:
    145
    Likes Received:
    0
    Trophy Points:
    0
    I have a 20-39 PC Plus and I really like it, but I've never heard the PC Ultra, so I can't really help with a comparison. I think you'd be happy either way, but I bet you'd be happiest with the Ultra, just because you wont have to ask yourself the dreaded "what if" question. I noticed that there is a B stock PC Ultra on the SVS website. May may your decision easier...
    http://svsubwoofers.com/Merchant2/me...y_Code=B-stock
    Better hurry. These things go fast! I bought mine B stock and I could not find a thing "wrong" with the subwoofer.
     
  3. Edward J M

    Edward J M Cinematographer

    Joined:
    Sep 22, 2002
    Messages:
    2,031
    Likes Received:
    0
    Trophy Points:
    0

    Yes, the dB-12 woofer is nipping at its heels in terms of THD limited output; the TV-12 has about a 1.5-2.0 dB advantage in that respect.

    But the TV-12 has an underhung VC that maintains a consistent motor strength over the entire excursion range. The TV-12 VC also has ridiculously high thermal power handling limits (several thousand watts for 8-10 seconds). This means it can continue to convert electrical energy into useable output (instead of wasted heat) under extremely adverse operating conditions.

    And yes, nearly all who have heard both woofers will tell you that the TV-12 subjectively sounds better than the dB-12, even at lower volumes.

    The dB-12 is a GREAT woofer for the price and offers the most bang for the buck in the SVS line-up. The TV-12 OTOH is the finest cost-no-object 12" woofer that TC-Sounds and Tom Vodhanel could design/build - PERIOD. A case of diminishing returns? Sure. But ask Tom, and he'll tell you the TV-12 is "worth every penny".

    Only you can decide if the premium is worth it, but rest assured the differences between the two woofers can definitely be heard and felt.
     
  4. Michael R Price

    Michael R Price Screenwriter

    Joined:
    Jul 22, 2001
    Messages:
    1,591
    Likes Received:
    0
    Trophy Points:
    0
    I would also venture that the Adire Sadhara has a very good sounding driver, probably better than a PC+ in terms of distortion and output, and it costs only $900 with an appropriate amplifier.
     
  5. ErichH

    ErichH Screenwriter

    Joined:
    Mar 1, 2001
    Messages:
    1,163
    Likes Received:
    0
    Trophy Points:
    0
    Ferdinand*T

    Edward's comment on motor strength is in line with my comment about recovery speed from months ago, when I set up my first CSU. There are a number of defining moments on soundtracks that you will never hear with another driver. I suspect the tube and dual box versions have their own differences (aside from the obvious) but the TV12's 2-4% difference is a BIG difference.

    A/B the sound of Fett's ship in the asteroid chase (SWs 2) and you'll get the idea. It's a very fast pulse down low that most subs can't reproduce with any authority. Some not at all.
    The Monsters Inc sock explosion is another good test. Not how low, but how quick.

    Good Luck with your choice

    E
     
  6. Edward J M

    Edward J M Cinematographer

    Joined:
    Sep 22, 2002
    Messages:
    2,031
    Likes Received:
    0
    Trophy Points:
    0


    I just finished testing a 20-39PC+ that I helped set-up and install locally. Naturally, the passive CS+ with the same driver will belt out nearly identical numbers.

    The 20-39PC+ ground plane data compares favorably to numbers Yates measured for the Sadhara:

    10% THD (unless otherwise noted) @ 2M GP:

    18 Hz 90.7 dB
    20 Hz 98.0 dB
    22 Hz 102.7 dB
    25 Hz 105.5 dB
    30 Hz 106.6 dB
    40 Hz 108.8 dB (8.45% amp limited)
    50 Hz 108.2 dB (5.58% amp limited)

    Add 6 dB for the 1M equivalent output (same as Yates).

    Regards,

    Ed
     
  7. Michael R Price

    Michael R Price Screenwriter

    Joined:
    Jul 22, 2001
    Messages:
    1,591
    Likes Received:
    0
    Trophy Points:
    0
    Ed, that is interesting, can you repeat the Sadhara THD numbers here? I can't find them. I am wondering if a difference in test method would contribute to an anomaly in the measurements. Since the Sadhara driver has 28 mm of excursion and a relatively linear BL profile, in addition to the big concentric cylinder port, one would think it is just as good or better.
     
  8. Edward J M

    Edward J M Cinematographer

    Joined:
    Sep 22, 2002
    Messages:
    2,031
    Likes Received:
    0
    Trophy Points:
    0
    Oh, I wasn't implying the PC+ dusted off the Sadhara. I just said it compared favorably.

    I don't have all the Sadhara numbers (Dan Wiggins will, or anyone else with the Ultimate AV Sub shoot-out issues). I do know Yates measured 104 dB @ 25 Hz @ 7.5% THD @ 2M, and then converted this to 110 dB @ 1M by adding 6 dB.

    Yates uses a different method to test THD than I do. I use straight sines at the shortest duration possible (i.e., just long enough to stabilize the RTA display and grab a screen shot). This helps prevent VC overheating problems, which can skew the test results.

    Yates uses a shaped tone burst to avoid the same problem; go here for details: http://www.guidetohometheater.com/news/050704yates/

    The only way to tell for sure obviously would be to test them under the same conditions with the same gear. Any anomalies introduced by gear and test methodology would then be a non-variable.

    Regardless, I agree the XBL2 is an impressive design and this is not to detract from it in the least; rather it was simply to point out that a well designed conventional woofer can still stack up well.

    I do think if a 20-39CS+ and a Sadhara (which is selling for $595 right now vs. $575 for the CS+) were compared under controlled conditions, it would be a pretty close contest. [​IMG]
     
  9. Ned

    Ned Supporting Actor

    Joined:
    Feb 20, 2000
    Messages:
    838
    Likes Received:
    0
    Trophy Points:
    0
    Interesting results for the PC+.

    From your pb2 ultra review-

    20 Hz Tune 10% THD Ground Plane 2M:
    16 Hz: 89.5 dB
    18 Hz: 100.7 dB (8.4% THD amp limited)
    20 Hz: 102.8 dB (9.4% THD amp limited)
    22 Hz: 104.9 dB (7.7% THD amp limited)
    25 Hz: 106 dB (6.2% THD amp limited)
    30 Hz: 109.5 dB (7.9% THD amp limited)
    40 Hz: 113.1 dB
    50 Hz: 112.2 dB


    vs 20-39CS+

    10% THD (unless otherwise noted) @ 2M GP:

    18 Hz 90.7 dB
    20 Hz 98.0 dB
    22 Hz 102.7 dB
    25 Hz 105.5 dB
    30 Hz 106.6 dB
    40 Hz 108.8 dB (8.45% amp limited)
    50 Hz 108.2 dB (5.58% amp limited)


    The CS+ is just 5db down at 20hz, but at 18hz it's 10db down. Dual CS+ would win above 20hz, but the PB2 Ultra wins below 20hz. That may be where the perceived difference in sound quality lies.
     

Share This Page