Equalization/Filtering for Sub and Shaker!

Discussion in 'Archived Threads 2001-2004' started by DerrickW, Mar 3, 2003.

  1. DerrickW

    DerrickW Stunt Coordinator

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    Here is the low-frequency part of the setup I am considering (only thing I currently have is the amp). This will be an apartment, so I'm thinking the bass shakers will help me keep the overall volume down without losing that impact feeling I love.

    -one Adire Tempest 4ohm
    -8 25W Aura Bass Shakers (8 ohm net, 4 per couch in array)
    -Parasound 1500A (205x2 8ohm, 315x2 4ohm)
    -HK 520

    1. Can I use the two channels separately on the Parasound like this? IE would I get 205W to the array of Bass Shakers and 315 to the Tempest?

    2. I think the HK520 offers x-over at 40/60/80/100 to the sub (not independent by channel though like the HK525). I haven't picked my mains yet, so I don't know for sure where I'll crossover, but probably 80Hz most of the time. I heard the FMOD 50Hz filter suggested for the Aura bass shakers- should I get one?

    3. Would an equalizer be recommended for the shakers and/or sub? I noticed that the Art 351 is recommended by SVS. Could I use the Art 355 and is it just the two channel version so I can do the sub and shaker separately? Should I still use the FMOD 50Hz on the shaker channel or can I just knock the upper frequencies down 12dB? Can I just use regular RCA interconnects with this setup?

    4. I am so tempted to get 2 Tempests or a Tumult, but don't need any complaints from neighbors. Will this be disappointing (room might be 20x15x8 and open to 9x11 kitchen and several doors)? Is 315W good for a Tempest? Any other suggestions?

    Thanks!
     
  2. DerrickW

    DerrickW Stunt Coordinator

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    ttt
     
  3. DerrickW

    DerrickW Stunt Coordinator

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    Some more info on question one! This is the response from Parasound: "You will get the output, but it is suggested to run both channels with matching speaker specifications." Why would this be? Should I simply not do it then? The amp even has separate power supplies for each channel: http://www.parasound.com/products/am...500aspecs.html
     
  4. Jonathan M

    Jonathan M Second Unit

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    Hi Derrick,

    Seeing as noone has yet chimed in, I thought I'd have a go...

    1. As Parasound has stated, yes you can use it as you describe, and looking at the specs of the amp, I don't see why it would be a problem. The amp does not have completely separate power supplies, as it uses a single transformer, albeit with dual secondaries. Note that one of these secondaries will have a larger load (The 4ohm section), but that will not be too much of a problem IMO. One has to question whether you will need 205watts of shaking power, though! Perhaps a cheap, old receiver would be better (Run 4 per channel for a 4 ohm load). Shakers don't need huge amounts of power in my experience.

    2. Don't bother getting the FMODs if you are getting equalization

    3. Your room response of the sub will benefit greatly from equalization. This will be different for the shakers, whose response is primarily effected by the modes of whatever they're bolted too. If you have a 2 channel EQ that can apply different responses to each channel, then you'll be all set. Shakers can be EQ'd using an SPL meter either sitting on the couch, or suspended above it. The levels will ofcourse be different. I suggest putting the SPL meter on the couch, and calibrating so that the sub level and the shaker level is the same, then play with the amount of shake from there.

    4. The other suggestion for a driver is the AV-15 which is between the Tempest and Tumult, and not too much more than the Tempest. You may want to try modelling them. You have a fairly large space, but given that you also have shakers, may not need more than the Tempest. It is up to you. Ofcourse, you can always go Dual Tempest in the future if you just get one. Note that the AV15 and Tumult use dual 4? ohm coils, so be careful about how you plan to power them. Two tempests (One off each channel of the Parasound) would produce a good amount of air movement.

    One more thing. You don't IMO need to use such a high class amp for the purpose of bass. Distortion and other factors are not as much of an issue, as the driver itself will be producing far more (Let alone things shaking in your room) before the amp's distortion becomes a factor. Also, most sub don't need a really stiff power supply, as bass is very much transient in nature. Ofcourse, it never hurts!
     
  5. DerrickW

    DerrickW Stunt Coordinator

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    5~. Jonathan, you are totally right about the amp as being overly qualified (in my opinion as well). I was looking into plate amps, and pro amps for the subs. But I quickly realized that since I already have the Parasound 1500A, but would need to sell it off to move down in quality, well I wouldn't really save any money. I originally bought it with a 5 channel amp for a 7 channel system, but decided that I don't really need to go 7 channel right now.

    1. 205 watts to the shakers is TONS, but the Aura shakers require 25 watts each to reach full shake, and there are 8 of them, so this should be ideal right? The couches are large and leather, so I am using 4 each (besides, these shakers are cheap!) I don't have an old receiver to use. These aren't the Pro Aura shakers, just the cheap weaker ones so 3-4 seem to be recommended for a couch.

    2. 3. Thanks! I am probably going to get the 355 Art dual channel equalizer then.

    4. I want a Tumult, but that is a lot for an apartment with neighbors! With this amp, I think the eventual route could be dual Tempests- but one would keep me out of trouble for now right? (and still be an improvement from the dual 10's in my current Polk PSW650) I would actually get a Tumult now if I could use the 1500A amp, but the Tumult has dual 2 ohm voice coils. IE I can only get a mono 4 ohm. The 1500A can do 315x2 into 4 ohm loads and 630 into an 8ohm mono, but is not rated for a 4ohm mono!
     
  6. DerrickW

    DerrickW Stunt Coordinator

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    3. In searches I found mention of other equalizers that were adjustable. In particular the BFD DSP1124. I'll do some more searches tomorrow, but any info?
     
  7. DerrickW

    DerrickW Stunt Coordinator

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    Now, here is the interesting part, I got a second email from the President of Parasound himself with a different response on using the two channels separately:

     

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