second sub for bass management?

Discussion in 'Archived Threads 2001-2004' started by Steve Cross, Oct 11, 2002.

  1. Steve Cross

    Steve Cross Agent

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    On my Sony sub there are regular speaker inputs and outputs for left/right speakers, if i bought a second sub for the rears, and set them as large on the receiver, would i get full range from my rears for dvd-a/sacd?
     
  2. Phil A

    Phil A Producer

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    I have 4 subs in my system, stereo (for music or operating in conjunction for ".1"), center and rears. If you put a sub on the rears you can either do it with a crossover or as I do, I run them full range and hook the sub speaker level inputs up to the amp outputs (positive and negative from one channel and the positive from the other) and set the sub so that it only plays where the rears do not so that it fills in the bass the rears don't do. Same for my center. I had another sub on the rears which I am saving for the basement that has its own electronics crossover built-in and I used it for a bit via the line level in and outputs. You should measure how far down your rears play, either with a RTA or if that is not available something like the Radio Shack SPL meter with a bass test disc. You want to fill in the bass that the rears don't play, not overlap what they play and get a big bass bump. Before you do that stuff you also may want to just test the room for how it handles bass frequencies in general and consider getting treatments to help tame any problems. So going the 1st step to measure can be helpful just to know how stuff reacts in your room (which you can't get from a store listen).
     
  3. Joe Cole

    Joe Cole Second Unit

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    Phil,

    Do you have of your subs attached to through L/R outs via a crossover? If you do, how does that set up perform for movie bass?

    I know you have SACD as I do. I have been thinking of moving my pair of 16-46 with the strong woofer to the l/r line outs. I am concerned that this would diminish the movie bass impact. I would still have my Velodyne 18" THX sub hooked up to the .1 out.

    Any comments?
     
  4. Phil A

    Phil A Producer

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    Joe, the ability to go full-range for multi-channel music is the main reason I did this. They are all Rels so they have the 2 inputs and volume controls. The center and surround subs are just connected via amp speaker level outputs and fill in the bass. I use stereo subs for music. For movies I split the sub out for "1." via a balanced 'Y' connnector I made going to the Rels. For music, there is no pre/pro crossover and the 2 Storm IIIs are actually set at 22HZ to mate with my Thiel 7.2s

    You can use your sub for both the way I do the bedroom system sub. I only watch about 5 movies a year in the bedroom system and put a Sunfire, Jr. in there. When I listen to music (usually via the Pioneer Elite DV-47A), I set my Sony 444ES receiver to analog direct (no processor or DACs) and have leads from the amp terminals (postive and negative from one channel and the positive from the other) going to the subs speaker level terminals with the crossover set just to fill in the bass my mains don't reproduce. When I watch a movie, I unplug the sub and very carefully remove the banana plugs and separate (from the sub) so they won't touch and short out anything (connected to the amp terminals), put the RCA jack from the receiver sub out into the sub input and turn the crossover on the sub up so that the processor in the receiver divides the bass going to the ".1" channel. I had the Rel Strata in the bedroom that is now on my main system rears and figured I could certainly make do with the Sunfire which is a very good sub in my bedroom which is a medium sized room. The key to making it sound right for music is to set it up properly with your room bass response. I would be happy to come over something with my RTA and test disc if you wanted to try it.
     
  5. Joe Cole

    Joe Cole Second Unit

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    Thanks Phil for your answer. I would want to use a crossover so as not to have to move wires all of the time. The main reason I want to do this is my Sony XA777es. When playing stereo SACDs I can choose the l/r outs only and that uses all six dacs for both CDs and SACDs. But there is not bass management for these two outs, If I choose stereo plus sub in puts the music through the 7.1 set of outs and is only using one set of dacs for stereo. It is not a great difference in detail but it is a little smoother and analog like through the l/r outs and the six dacs. If I had not read the Stereophile review of this SACD player I might not have know about it and ignorance would have been bliss. na I would have found out sooner or later.
    Also part of my problem is I have a pair of balanced AQ Diamonds interconnects for stereo from pre/pro to 2 channel amp. I'd hate to mix a pair of cheaper cables with them in the crossover and I'd have to get a pair of adapters that go from balanced to rca. I guess I will just listen to jazz and lighter classical with out the subs and live with it. My Martin Logans have ok bass. good enough for that kind of music.
    I am trying to figure out how much bass is carry on the l/r channels for films. If it is close to the .1 out I might try the cross over.
    However, I finally broke down and bought a leather lazyboy recliner(the one with the lowest back) and now am broke again. [​IMG]
     
  6. Phil A

    Phil A Producer

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    Joe, interesting about the XA-777ES. I have one and did not know that but mine is set as if all my speakers are full range since I have 4 subs (stereo, center and rear). My biggest decisions are whether to consider getting a mod done and more immediate, I just picked up a TA-P9000ES and am running the 5.1 channel out of the 777ES into the bypass input (I have not noticed any difference so far) and the DVD-A player (DV-47A in the bedroom on the other side of the wall) into input one and use the analog volume controls on the TA-P9000ES to adjust the levels of the center and rears. I adjust the levels of the 777ES in the player and I guess I'll have to eventually do some detailed listening back and forth.

    For your 2-channel you could do something similar to what I did. My Bryston SP 1.7 has balanced outs (except for the rear center) and I made a custom Y connector from the balanced sub out to 2 subs for the ".1" channel. Or perhaps easier is just connect and disconnect the single-ended output of the 2-channel preamp to the sub. Swapping RCAs for music for movies should be easy (you could even get a high isolation A/B switch for $8 and and 'F' to RCA adapters (especially now that you have a lazy boy chair that is bound to make you lazier). The other factor is the volume and crossover. If the volume is around the same for bass output levels then all you need to do for movies is move the crossover up to let the processor setting control and move it down to match your speakers and room for music.
     

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