20-39 pc plus or hsu tn1220HO w/500 watt amp

Discussion in 'Speakers' started by Justin_collins, Jul 23, 2003.

  1. Justin_collins

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    I have paradigms studio 100's, cc, 20's for surrounds. I would like to know which subwoofer is the better. I have no real way to compare these so I ask for you opinions. Room size being held constant. Thanks for your time. Justin.
     
  2. Edward J M

    Edward J M Cinematographer

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    To get comparable features and performance from the HSU, you would also need to purchase the HSU Bass Optimizer Box for $100, getting you up to $1,300 shipped.

    A fairer (to HSU) comparison would be the 20-39 CS-Plus with the 500 Samson amp and the Bass Interface Box for about $1,200 shipped.

    But since HSU does not offer a powered cylinder AND you did specifically ask about the 20-39 PC-Plus (about $860 shipped), here goes:

    Internal volume and EQ:
    The SVS has a much larger internal volume than the HSU. This allows the SVS to achieve its stock tune of 20 Hz without the assistance of EQ. In order to achieve its rated extension, the HSU requires a 6 dB boost at 18 Hz from the Bass Optimizer box. There is nothing inherently wrong with using EQ to achieve deeper extension, but it does use available amp power that would otherwise be used for an increase in SPL.

    Port area:
    The SVS uses three 3" flared ports versus a single flared port on the HSU. The SVS has more port area for better airflow and higher SPL potential at the lowest frequencies.

    Power:
    The SVS has a 525W amp, and the HSU has a 500W amp, but some of that power is being used for EQ.

    Tuning flexibility:
    The SVS can be tuned to 20, 16, or even 12 Hz with the factory supplied port plugs. The HSU cannot be tuned, although either sub can hardly be faulted for a lack of deep extension in the stock tune.

    SS Filters:
    The SVS has a 4 position SS filter with settings for 25, 20, 16, and 12 Hz to correspond with the various tuning points. The HSU Bass Optimizer box has one SS filter point (15 Hz) at the EQ1 setting specifically designated for the TN1220 HO. In addition, the filter rate for the HSU unit is a fairly shallow 12 dB/octave, while the SVS unit is a steeper 24 dB/octave.

    Phase Control:
    The SVS has an infinitely variable phase control between 0 and 180 degrees. The HSU has no phase control on the 500 watt amp or the Bass Optimizer box. In a room with difficult tuning modes, or where two subs are employed in different locations, infinitely variable phase is a big advantage.

    Drivers:
    Both the SVS and the HSU employ high excursion 12" drivers. To quote Ron Stimpson of SVS, the HSU driver is "simply not in the same league as the TC-Sounds built Plus woofer SVS designed".

    Summary:

    The SVS has comparable extension without needing EQ, more port area, more tuning flexibility (for an even deeper tune if desired), a more effective SS filter, variable phase control, and a better driver. All for about $450 LESS shipped.

    Not only that, the SVS has all controls and features on board, and has the plug and play convenience advantage over the HSU.

    Regards,

    Ed
     
  3. terence

    terence Supporting Actor

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    Well i guess Ed put the nail in this thread.[​IMG] [​IMG]
     
  4. CurtisSC

    CurtisSC Screenwriter

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    real quickly....

    If you use the Hsu 500watt amp, you do not need the Bass Optimizer.

    Hsu 500watt amp can handle two TN1220's giving each 400watts.

    There is a phase switch..but not variable.

    That's all I have off of the top of my head at the moment.

    You really should listen to both to find which is better for you and make sure you have accurate info.

    But surely two very nice subs.
     
  5. CurtisSC

    CurtisSC Screenwriter

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    OK....more clarifications for you.

    The Hsu is a 6th order bass reflex system that has higher efficiency in the mid/upper bass. The use of eq simply brings the lower bass efficiency in line with mid/upper bass. As with the SVS amps, Hsu amps are puposely built for the application. That's one reason why the TN1220HO can play very loudly and cleanly from 20Hz on up with even "only" a 250 watt amp. The 6th order design is very efficient. The TN1220HO setup with 500 watt amp is just more capable.

    The TN1220HO/500 watt amp can play very cleanly and very loudly even with "only" a 4 inch port because of the clever design. With the port firing downward, much of the port noise can effectively be absorbed by the surface below particularly on carpet. Ferstler tested a single TN1220HO/250 watt amp to have a clean 110db's at 20Hz at the listening position, with no detectable port noise. Having a Ph.D from MIT counts for something.

    The amp is also is a very high quality component (class A crossover, class H amp) that is just as suitable for 2-channel setups as it is HT setups. It also employs a 24 db/octave slope, not a 12db/oct slope.

    If you can, you need to listen to the two subs in question. One does not outclass the other. Do you research. They are different designs attempting to achieve the same goals.

    Let your ears be the judge.
     
  6. Edward J M

    Edward J M Cinematographer

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    Curtis:

    I guess the 500 watt amp has built in EQ? Thanks for clarifying that. And I didn't see a phase switch listed in the features on the amp.

    The low pass filter network on the amp is indeed 24 dB/octave (standard), but I was not referring to that. Most people will use the high/low pass filters in the bass management circuit of their AVR or pre/pro anyway.

    I was referring to the slope rate of the SS filter in the Bass Optimizer box, which is listed at 12 dB/octave.

    Does the 500 watt amp have a built in SS filter? If so, what is the filter rate?

    Thanks,

    Ed
     
  7. CurtisSC

    CurtisSC Screenwriter

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    Hey Ed,

     
  8. Mike Sloan

    Mike Sloan Second Unit

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    If the TN1220HO is more potent than the VTF-3 (and it should be) I can only imagine it would sound great. I have never heard it...I have heard the SVS 20-39PC+ and it is a fantastic sub for both music and HT! I would bet there would not be a whole lot of difference between these two subs.
     
  9. CurtisSC

    CurtisSC Screenwriter

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    the TN1220HO with the 250watt amp gets better low end output than the VTF-3, and is cleaner.
     
  10. Jack Gilvey

    Jack Gilvey Producer

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  11. Justin_collins

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    Thank you all for the information. I'm very appreciative .
     
  12. Edward J M

    Edward J M Cinematographer

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    Curtis:

    If the amp is purpose built for running the TN1220HO, it would probably be a safe bet it incorporates the same circuitry as the Bass Optimizer box. That is, the same EQ curves and SS filter points/rates. Why fiddle with success or reinvent the wheel?

    As I stated above, a much fairer and apples-to-apples comparison would be the passive SVS 20-39 CS-Plus, Samson 2-channel 500 watt amp, and SVS01 Bass Interface Box. If you don't need the Bass Optimizer box in the HSU package, the price for both packages becomes almost the same and they can be judged exclusively on their relative performance merits with price issues set aside.

    Jack, you just beat me to the punch here, so I'll ask you and/or Curtis to help me out here. In this particular instance, what is the difference between the 6th order bass reflex system that you indicated HSU employs, and the 4th order bass reflex system? What is more efficient about the design? The HSU appears to have a surface mounted driver and an opposing tuned vent, just like the SVS design.

    Regarding the driver designs, until someone lays out the T/S parameters of both drivers and/or measures their outright performance differences, I will grant anything less is heresay. With that said, being that SVS and HSU are direct competitors, I would imagine SVS is well aware of the performance capabilities of the 12" HSU driver in order to make a statement like that. And while a 20 pound magnet structure is at first blush impressive, the strength of a magnetic field is not solely a function of magnet weight.

    Regardless, whether we are comparing the HSU package to the PC-Plus or the CS-Plus/Samson/Marchand Bass Box, it is still my opinion that the SVS has the following advantages:

    1) 0-180 continuously variable phase vs. 0/180 switch.

    2) Variable tuning (20, 16, 12) vs. a fixed tune.

    3) Variable SS filter points vs. a fixed point (HSU assumed to be 15 Hz - same as Bass Optimizer Box).

    4) A steeper SS filter rate 24 dB/octave vs. 12 dB/octave (HSU assumed to be same as Bass Optimizer box).

    5) 70% more port area in the stock 20 Hz tune. A single 4" flared port cannot possibly flow as much air as three 3" flared ports. Even with a port plugged in the 16 Hz tune, the SVS still has a 15% advantage in port area. And I don't think there is anything particularly clever about employing a downward firing port in the hopes that carpeting will absorb any port noise that might be generated.

    6) A larger enclosure volume which allows naturally deep extension without the use of equalization. Again, there is nothing wrong with using EQ, but if we are comparing designs, the use of EQ does require some amplifier power that would otherwise be used for a linear increase in sound pressure level.

    7) A bottom-mounted, bottom-firing driver vs. a top-mounted, top-firing driver. The SVS design will have a much lower center of gravity, will be less prone to accidental tip-over, and is much more protective of the driver.

    I'm not saying the HSU design is poor, quite the contrary - the great reviews of this subwoofer certainly do the talking for HSU. It is my opinion that the SVS has certain design features that offer distinct advantages to the user.

    I have a 20-39 PC-Plus at my disposal at any time. I'll host a friendly face off anytime with a TN1220HO owner in the upstate NY area and post the subjective impressions from both owners and the objective results right here on HTF, win or lose.

    Regards,

    Ed
     
  13. CurtisSC

    CurtisSC Screenwriter

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    Ed,

    I will do the research on the 6th order vs. 4th order for you if Jack or someone else does not pipe in first. I did not realize the SVS had a 4th order design. Can you list advantages of the SVS 4th order design? I'd like to learn as much as possible. And I will research your assumptions.

    I am not saying the TN1220HO is a better sub. I just wanted to make sure the poster had unbiased information.

    I fully respect your opinion that the SVS sub is better. Like you, I have not heard both subs.

    A faceoff would be nice, hopefully someone will step up. But like you said, it is subjective, so it is not a win or lose situation.

    curtis
     
  14. CurtisSC

    CurtisSC Screenwriter

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    Thanks Jack. Saved me some work.
     
  15. Edward J M

    Edward J M Cinematographer

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    I was thinking the HSU was acoustically a 4th order vented design. An acoustically 6th order bass reflex design would require enclosure space and a tuned vent both in front of the driver, as well as behind it, correct?

    So you are saying the simple application of a 2nd order (12 dB/octave) subsonic filter causes the subwoofer to be classified as a 6th order system?

    Following your logic, would the application of a 4th order (24 dB/octave) SS filter to a 4th order subwoofer result in an 8th order "system", or is there no such animal?

    Regardless, if the HSU is truly a 4th order vented design (and I think it is), the enclosure size and port length would dicate a natural roll-off somewhere around 30 Hz. That alone might explain its high output above that point and could be what Curtis was getting at with his efficiency statements. It is well known that the SVS 25-31 enclosure with its higher (compared to the 20-39 and 16-46 enclosures) 25 Hz tuning point will play the loudest (above its tune point) of the three enclosure sizes.

    My next question is which would have the overall output advantage - all other things (driver, amp) being equal:

    1) An enclosure and venting system naturally sized to produce a native 20 Hz tune and by virtue of this fact has comparatively lower output potential at higher bass frequencies, or;

    2) A smaller enclosure and venting system naturally sized to produce a native 30 Hz tune and by virtue of this fact has comparatively higher output potential at higher bass frequencies, but which then also requires EQ to achieve the same 20 Hz tune?

    Thanks,

    Ed
     
  16. CurtisSC

    CurtisSC Screenwriter

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    OK....this is now getting over my head, and I think I know where this is headed.

    Ed, I'm not here to pick at designs. Was never the intent.

    The whole intent was to correct information you gave to the poster.

    Like I said, I fully respect your opinion that SVS is a better sub, and until I I've heard one, I will not agree or disagree with you.

    Like with all speaker designs, there are differences, which make them sound different. The bottomline is how it sounds to someone in the end. What sounds good to me, may not sound good to you...and vice versa.

    Hsu and SVS make great stuff. We should not diminish their work here.

    curtis
     
  17. CurtisSC

    CurtisSC Screenwriter

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    Jack,

    Totally understood. Someone with more knowledge, such as yourself is better suited for this discussion.

    I made the diminish comment because of where I thought the thread was headed.

    Like I mentioned, the intent of my first couple of posts were to correct information Ed listed about Hsu's product, nothing more.
     
  18. Edward J M

    Edward J M Cinematographer

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    [QUOTE The higher the tuning point the higher the frequency that driver excursion begins to lessen, and the less deep bass is has to produce on its own.

    The Hsu, on the other hand, has a fixed 17Hz Fb and it begins to roll off where it does due to the box size reducing sensitivity as the box approaches Fb.[/quote]

    So the fact that a 4th order vented alignment has an Fb of 18 Hz does not necessarily mean it will produce a flat output down to the frequency? And this is due to the smaller enclosure size limiting the efficiency as the frequency drops?

    So in comparison, the SVS design has an Fb of 25, 20, and 16 Hz (per each enclosure), and maintains a linear output down to Fb by virtue of its larger (and hence more efficient) enclosure?

    While the HSU in comparison has a fixed Fb at 17 Hz but requires equalization in order to maintain a linear output down to the Fb due to its comparatively smaller enclosure?

    Honestly Curtis, I'm not picking at designs at this point and I'm not headed anywhere. If Jack says the TN1220 HO is a great sub, I believe it, my other comments not withstanding. I do appreciate your help in pointing out the mistakes in my first post and it was never my intent to intentionally deceive Justin by providing him with deliberate misinformation. I'm simply taking the opportunity to pick Jack's brain while I have his attention. While he is a self-proclaimed idiot, I tend to think otherwise and I'm trying to further my knowledge of subwoofer theory and design at his expense. I still owe him a beer if he ever gets to "this side of the river", you know. [​IMG]

    Thanks,

    Ed
     

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