Hsu Bass Optimizer

Discussion in 'Archived Threads 2001-2004' started by Gil D, May 28, 2002.

  1. Gil D

    Gil D Supporting Actor

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    How much of an improvement would the Bass optimizer have on a TN1220HO run by a non-Hsu amplifier.

    Hsu also mentions that the box can be configured as a hi pass filter but seems like you lose the bass optimizer feature. It would really be nice if I could use it as bass enhance or hi pass filter - can one be easily modified by changing a few internal components? Has anyone used it as a hi pass for their mains and can comment on it's performance. What powers this box anyway?
     
  2. ling_w

    ling_w Second Unit

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    The stock TN subs has a natural rolloff from 40hz or so due to the overdamped alignment built into its design. It is down roughly 6dB @ 18-19hz.
    Without the underdamp alignment, the speaker is roughly down 3dB @ 25hz, fitting that generic THX specification.
    With the optimizer, the sub would be flat to 19hz and down ~2dB at the port tuning freq of 16hz.
    When it is reconfigured as a high pass filter, the circuitry becomes completely different. Instead of the integrator and 2nd order rolloff, with each circuitry requiring its own caps and resistors. If they reconfigure it to be a high pass filter (actually they configure it with 2 freq, selectable by the toggle switch,) The would probably utilize the 2nd order filter's circuitry, except with different component values. Plus the switch would control resistor values for the high pass instead of the componentes in the integrator/2nd order unit.
    In theory, the 2nd order rolloff from the original unit could be reconfigured to be used as a high pass by changing the resistor values. But the integrator is not by-passable, giving your initial 12dB/oct rolloff to become a 6dB/oct at the freq the integratrator takes effect, roughly 40-50hz, depending on front panel switch setting.
    As you can see in the picture, it is powered by a external wall wart:
    [​IMG]
    The quality of the sound should be even better than the crossover in the 500w amp due to its use of discrete metal film resistors instead of the std resistor array DIP chip used in the 500w amp.
     
  3. Gil D

    Gil D Supporting Actor

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    ling,

    Thanks for the info.
    Is the walwart included with the optimizer? If not is their any particular one that you recommend that is low ripple and noise. I'm not sure how well the optimizer combats power supply noise (regulators, filters, etc).

    I run the TN1220 using the LFE mono output of my Denon receiver to the amp that drives the TN1220, the main speakers are set to small. How do I connect the optimizer with this setup?

    Since the optimizer has stereo I suspect I could set the mains as large no sub and connect the main preouts to the optimizer - but not sure which output connects to the sub amp, and if I can even do this. If so, would this be the preferred approach or the mono method above. What is the input impedance of the optimizer - I would need to Y of the receiver's preouts to drive both the amp and optimizer.

    Also, as an aside. I am considering another sub for a separate theater room and now have the TN1220HO and VTF-3 to choose from Hsu. How does the new VTF-3 compare to the TN1220 in terms of home theater and music performance.

    Gil
     
  4. ling_w

    ling_w Second Unit

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    Gil,

    The wall wart is included, or how else would one operate it when the get one? I don't know its effectiveness, but you could twist the wall-wart wires to decrease the likely of noise pickup, or wrap it in foil/braid/wire shield and ground the end to the ground connector in the outlet.

    If you connect your sub to your LFE, then the optimizer would sit between the LFE out and the sub amp in.

    If you set your spakers to large and no-sub, then you would need 3 optimizers, one to roll off your mains at a pre-determined freq, the 2nd to roll off your bass, and the third for bass equalization.

    The purpose of the Bass-optimizer is for people who runs their sub via LFE, that is why it doesn't even come with a low pass filter. If you want to run your speaker as large/no-sub, you would be better off getting a Hsu's 500w or 250w amp that has active high and low pass crossover. Even his old amps has the same xo/bass optimizing function as his latest 500w unit.

    Input impedence is 100kohm. Should pose no problem to any premap.


    VTF-3 is more preferred for HT since it provides max-output mode for increased handling capability in the >30hz range. Plus its all in one unit is more straight-forward for LFE application.

    But the TN has more bass capability in the 20hz range, and it's cylindrical design results in less cabinet coloration.
     

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