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Questions for MJA Acoustics Reference 100 owners

Discussion in 'Home Cinema Speakers' started by kipper15, Feb 23, 2004.

  1. kipper15

    kipper15
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    Does the MJA Ref 100 sub have 2 x phono RCA inputs for the LFE? If so, do both have to be used? I've been looking at the pics on their website...I might be mistaken but it looks like a pair of phono RCA inputs on the back of the unit.

    My amp only has a single subwoofer input. So if a pair of phono cables has to be used with the Ref 100, presumably I'd need a Y-connector of some sort at the amp end?

    Also...what's the low-level cable like that comes with the MJA subs? Is it any good or should I replace it with a 3rd party one?

    Anyone able to tell me the answers?
     
  2. hornydragon

    hornydragon
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    I am saving for one of these, you can use a "Y" splitter but normally the Left LFE input will work. Hope this helps.
     
  3. MuFu

    MuFu
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    Nope. There's no benefit to using a Y-splitter.
     
  4. BiggieBig

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    I used a good quality Y connector on a Celestion S10 Sub

    QED Y - Splitter £35 from hifi bliz.

    I did a test with & without the splitter the gain in bass was immediately noticeable.

    But them I guess it probably depends on how the sub wiring is connected internally ??????
     
  5. kipper15

    kipper15
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    Hmmm....some differing opinions here. I wonder if there really is a definite answer to this one, or whether it's purely subjective.

    I would have thought a single LFE input into the sub would do the trick.
     
  6. BiggieBig

    BiggieBig
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    It does the trick but you get much more gain by using a y adaptor
    on my sub anyway, I was unsure at first but borrowed my brothers Y adaptor to do a test, the result was just so obvious.

    Might be to do with the fact that if you use two connectors then your halfing the impedence because you have two connections in parallel.
     
  7. Ian J

    Ian J
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    It will and whilst if both inputs were being used it may result in more gain it would mean having to recalibrate the sub and reduce the gain on the sub to compensate.

    Some people use a splitter into both inputs as on some poorly designed American subs there seem to be problems with the "auto on" function at normal input levels and a higher amount of gain is needed to wake the thing up.

    Most decent subs will either not have this function or a switch to switch it off as in general it is more nuisance than useful feature.
     
  8. kipper15

    kipper15
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    Thanks guys...seems like the Y-splitter is not neccessary. Presumably I could use the Right LFE input connected to one of the preouts on my stereo amp?

    So, in this scenario the connections would be like this:

    Arcam A75: connected to Right LFE low-level input on sub via one of the preouts. When playing music, will get stereo + sub LFE.

    Pioneer VSXD812 (which is connected to the Arcam via the preouts for front L/R speakers): connected to Left LFE low-level input on sub via the sub preout. When playing movies, will get multi-channel + sub LFE.

    Would the above be sensible or am I losing the plot? :blush:
     
  9. Roam

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    For your stereo amp it's better to use the high level connection and the low level (right mono RCA) with your receiver for movies and set the gain for each independantly. Also change the crossover setting each time you switch between stereo and movies. I know it's a pain but this way you will get the best out of your sub.
     
  10. kipper15

    kipper15
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    Interesting...that's the opposite of what Arcam have suggested!! The reason for using the low-level cables with both the Arcam stereo amp and the Pioneer AV receiver is because the Arcam amp has BFA plugs tightly connected into the BFA speaker connectors. It will therefore be more difficult to establish a good connection with both the BFA plugs and the high-level cable wires stuffed into the same speaker sockets on the A75.

    Also, if I have two outputs into the LFE on the sub (one from the stereo amp; the other from the AV receiver, then am I right in saying I don't have to change the crossover setting each time I switch between music and movies?
     
  11. Roam

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    I must admit I'm not too familiar with BFA plugs/connectors so can't help there. :blush:

    If you are only connecting one of the preouts from your stereo amp then will you only get the bass from one speaker?

    Can I suggest you buy a short Y cable and plug the single end into the right (mono) RCA connector on the sub. Take a pair of interconnects and plug them into your Arcam's preouts and plug one end into the left RCA of your sub and one into one side of your Y cable. Then take the single sub output from your receiver (it's a mono signal) and plug it into the other side of your Y cable. I think this should work but correct me if I'm wrong (anybody!). The only problem I can see is that one side of your stereo length will be a little longer than the other but I suspect it won't matter.

    I believe both the gain and crossover will have to be set independantly as your receivers crossover will probably be set at 80Hz (not sure on Pioneer's) and the crossover setting on your Arcam will depend on your speakers bass ability (how low they go). As far as the gain goes I find the settings for music and movies are quite different (comparing high and low level anyway). You will know for sure when you try it out for yourself but I suspect they will be different.

    Not definitive answers you understand but hope they are of some use.
     
  12. kipper15

    kipper15
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    Thanks Grinder....having read your post and given this some more thought, I think the best option is to actually cut the BFA plugs at the (Arcam) amplifier end of the speaker cables and use bare-wire speaker cables to connect to the amp. That way I can use the high-level cable AND the low level cable - the way that MJA themselves recommend.
     

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