Bunch of adding subwoofer questions

Discussion in 'Speakers' started by Messy Jesse, Oct 11, 2017.

  1. Messy Jesse

    Messy Jesse New Member

    Messages:
    22
    Hi Folks,

    Thinking about adding a powered sub to my system (2 channel receiver, no pre in/outs) to help my bookshelves with the low end. I have zero experience with subs but love projects. I want to build one of the DIY kits from Parts Express, should be fun. Ideally I'd like the thing to blend seamlessly with my system and not be adjusting knobs every time I change volume or music genre. I THINK that means I want to use speaker level inputs on the sub. So that's the first question. Does using speaker level input on the sub truly adjust the level based on the receiver's volume (in a linear/proportional way) so that I can set and forget?

    Next question: I have no idea if I'll want to run my bookshelves full range or if I want to use some sort of crossover/low pass deal. I think I want the option to try that to see if I prefer it either way. Some subs have HF out, but none that I've seen above 300watts or so. I also don't love the idea of running my speaker cables all the way to the sub, then all the way back to the speakers. I know I could wire in some capacitors to my mains to take out the lows, but I think some adjustability or the option to turn full range on or off would be nice. I guess I could build a little custom box with knobs and switches. Could be fun. Anybody have a clean and not too expensive solution to this one?

    Last one: Does using the high level input on the sub truly not add any (relevant) load to the receiver?

    Thanks!
     
  2. Nick9000

    Nick9000 New Member

    Messages:
    5
    If your receiver has a second set of speaker outputs, you can run those into the subwoofer's speaker level inputs, so you don't have to run speaker wire from the sub to the speakers. Once you get it locked in, you should be able to set it and forget it. And I'd definitely recommend using a crossover to cut the low frequencies to the speakers, but that won't work if you use the secondary speaker outputs. The speakers will sound better if they aren't struggling to produce the low end. The easiest way would be to use the crossover on the sub. But of course, that means running speaker wire to and from the sub, which you (understandably) don't want to do. But really, once it's set up, are you really gonna notice those speaker wires?

    Good luck!
    N
     
  3. bigx5murf

    bigx5murf Well-Known Member

    Messages:
    822
    Location:
    Las Vegas
    This is one of the reasons I like AVRs for 2.1 setups. Lots of control over sub integration.

    Knowing what features the amp you plan on using would narrow down options.
     
  4. Messy Jesse

    Messy Jesse New Member

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    22
    Using a Nikko 8085 receiver powering EPI 100 speakers. It's got tape outs, but no "ins". I can do A, B, C, A&B, or A&C channels. However, I've got A as my mains and C to my patio speakers. B is pretty much just used to audition new speakers occasionally, but nothing sticks around. I'd prefer not to put the sub on B because I could envision a party scenario where I'd want my main system on with sub, plus the patio... Pretty rare scenario, but it could happen.
     
    Last edited: Oct 11, 2017
  5. whoaru99

    whoaru99 Epic Member

    Messages:
    39,372
    Location:
    LoTL
    The answer to all your original questions is "Yes, that's correct".

    Sounds like you've done your homework.

    The only roadblock is the high pass for your main speakers. Generally speaking, they're not adjustable at speaker level so you end up with whatever one is built into the sub, or whatever you experiment with externally.

    A simple capacitor provides an additional 6dB/oct roll off on the low end. That can easily be shorted out with a parallel switch to provide a high pass or full range setting. A 12dB/oct could be switched in or out pretty easy too.
     
  6. JoeESP9

    JoeESP9 ESL's & tubes since 83

    Messages:
    14,799
    Location:
    Philadelphia PA
    Although I have a pre/pro with 7.1 output I prefer to set the speakers at full range and use my DBX crossover to do the highpass/lowpass separation.
     
  7. SaturationPt

    SaturationPt AK Subscriber Subscriber

    Messages:
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    Location:
    N.E. Indiana
    Look up minidsp. This is a very nice DSP that sells for around $100 and is a great stereo crossover, you can set the frequency and type.

    You run your pre-out to the minidsp high-pass two outputs back to your amp ins, low-pass the other two outputs to your sub low-level in.

    This way you can play with overlap, run full-range to your mains, traditional high-pass / low-pass, change crossover frequencies, ... great way to get started IMO especially with a DIY sub.
     
  8. slow_jazz

    slow_jazz Lunatic Member

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    13,317
    Location:
    SE Michigan, Downriver....
    I have powered sub I run off my headphone jack. Low level input.
     
  9. Messy Jesse

    Messy Jesse New Member

    Messages:
    22
    I don't have pre outs/ins. Just Tape out A B. Can the minidsp handle speaker level?

    That's interesting. I guess doing it that way I would get a linear bass response (vs. line out) depending on receiver volume. Do you experience clipping (or worse) or noise from too hot or low of a signal?
     
  10. SaturationPt

    SaturationPt AK Subscriber Subscriber

    Messages:
    967
    Location:
    N.E. Indiana
    The minidsp I'm familiar with is only line-level, I don't have anything speaker level (sorry). However, I suspect that there is such a passive crossover available (such as the one in your speaker) and it certainly can be built.
     
  11. JoeESP9

    JoeESP9 ESL's & tubes since 83

    Messages:
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    Location:
    Philadelphia PA
    The Paradigm X-10 is a speaker level crossover for subs.
     
  12. whoaru99

    whoaru99 Epic Member

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    LoTL
  13. TomInTacoma

    TomInTacoma Well-Known Member

    Messages:
    651
    Location:
    DuPont, WA
    What I've done is use speaker leads as input to the sub and then connect the speakers to the sub output (it's a pass-thru signal). I have two separate set ups - one includes a Snell sub and Carver Amazing Loudspeakers, the other uses a Yamaha sub and Dynaco A-25's The first set is "A", the second is "B". I don't think there's any need to remove the low end from the speakers since the 'subs' are just that - 'subs'.

    Try going that route and see if you're happy with it. You can tweak it from there.
     
    stish likes this.
  14. neevo

    neevo Well-Known Member

    Messages:
    542
    Location:
    Sydney, Australia
    My understanding of line level inputs for the sub is that you could run them off the same speaker jacks as your mains. The current draw for the sub is so low that it wouldn't impact the mains at all.

    I run line level inputs for my stereo subs (L&R. When I had 1 I bridged the L&R) off speaker B outputs and run my mains off speaker A which means I run my speakers full range. Generally this isn't a problem and it sounds amazing, however when you push the volume it can have an impact on the mains if they are not setup for low bass as they will try and push a lot of air too.

    I'm running LS50's which are small speakers and I cannot run them super loud as the woofers would clip. If I had the ability to low cut the mains then I could push the volume a little harder but generally I don't ever play at these volumes anyway as that would be crazy loud!
     

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