redrich2000 Posted July 29, 2015 Share Posted July 29, 2015 I've just picked up a Jenson Qx-80 sub. It's the first sub I've owned so I need some advice on setting it up. The system is very basic and cobbled together. a Denon micro stereo receiver (UDM31; 2x22w into 6Ω) and a pair of Kenwood LS-9070 floor standing fronts. The Denon has an unattenuatted full range subwoofer out via a single RCA jack. The Sub has L/R (paralleled) "low level" RCA ins and outs, plus double speaker wire terminals in and out. The floor speakers are 3-way, 6 driver; 48Hz to 30kHz 8Ω, 130w max I don't think the Denon has any settings to designate speakers as small. So, the first question is whether to just go the simple route and connect the sub to Denon sub out via a single RCA cable. Or, wire the sub to the Denon, then wire the fronts to the sub? Link to comment Share on other sites More sharing options...
VanArn Posted July 29, 2015 Share Posted July 29, 2015 The plate amplifier fitted to the Jensen sums the L and R signals and the Denon offers a summed signal,so you will receive a sub-bass signal in its entirety with a single RCA to RCA cable. Link to comment Share on other sites More sharing options...
redrich2000 Posted July 29, 2015 Author Share Posted July 29, 2015 The plate amplifier fitted to the Jensen sums the L and R signals and the Denon offers a summed signal,so you will receive a sub-bass signal in its entirety with a single RCA to RCA cable. But is it okay that there'll be no filtering of the bass going to the front speakers? Or does the Denon handle that automatically if a sub is plugged in? Link to comment Share on other sites More sharing options...
almikel Posted July 29, 2015 Share Posted July 29, 2015 (edited) try it both ways and see which sounds better. sometimes it's good to have overlapping bass sources in the room (ie simply using the RCA out for the sub), but it's difficult to know until you've tried (and better still measured). More bass sources can assist in smoothing bass response in the room. Note that when you say "unattenuated" above, it's a pre-out, so it will be after volume control (which is what you want) cheers Mike Edited July 29, 2015 by almikel Link to comment Share on other sites More sharing options...
redrich2000 Posted July 29, 2015 Author Share Posted July 29, 2015 Okay, thanks for the help. Will probably go with mono-RCA initially for simplicity, then have a play if I'm not happy with the results. 1 Link to comment Share on other sites More sharing options...
VanArn Posted July 29, 2015 Share Posted July 29, 2015 Yes,a little experimentation to achieve the best blend with your Denon receiver is in order.The phase and high pass frequency adjustment controls on the QX 80 will help with this and you can use the bass tone control on the amplifier to reduce the amount of bass being fed to the Kenwood speakers,if you feel it gives better result. Link to comment Share on other sites More sharing options...
redrich2000 Posted July 29, 2015 Author Share Posted July 29, 2015 Yes,a little experimentation to achieve the best blend with your Denon receiver is in order.The phase and high pass frequency adjustment controls on the QX 80 will help with this and you can use the bass tone control on the amplifier to reduce the amount of bass being fed to the Kenwood speakers,if you feel it gives better result. Ah yes, pre out will mean before any of those adjustments won't it, so I can adjust there. Thanks everyone. 1 Link to comment Share on other sites More sharing options...
redrich2000 Posted July 29, 2015 Author Share Posted July 29, 2015 Sub is now hooked up and thumping. I don't think the auto-off feature is working though, is this a common fault or is it possible I've done something wrong? Another question... what do you guys think about the 2x22w receiver powering the Kenwood speakers. I'm wondering whether I'd get get better quality out of them with a bit more juice. I have very limited space so can't really upgrade to anything bigger. But I could stick a still amp in the chain? 1 Link to comment Share on other sites More sharing options...
Stedes Posted July 30, 2015 Share Posted July 30, 2015 Have you tried the original speakers that came with the Denon now that you have a sub or did you just get the receiver without the speakers? Also...I wouldn't worry too much about small/large and bass to the Kenwoods. They're a full range speaker and designed to handle an amount and level of bass below which they will roll off courtesy of their crossover and driver characteristics. If you do want to have low pass filtering then the only way to do that is to use the high level inputs on the sub - i.e. Denon - Speaker cable --> Sub and then Sub (speaker cable) --> Kenwoods. In that way the Kenwoods would only be getting frequencies above what you set on the sub. Oh and...don't forget to turn off that bass boost thing that the Denon has when you connect the sub. Link to comment Share on other sites More sharing options...
redrich2000 Posted November 9, 2017 Author Share Posted November 9, 2017 Just reviving this thread... I have just picked up a used Cambridge Topaz SR10. I realised after I got it there was a revision that added a sub out to this. I got the V1 without. So now wiring the sub, what's best amp>speakers&sub (the amp has two sets of speaker outs) or amp>sub>speakers? I don't know much about the speakers. They are think Kenwood fronts, 3-way, 6 drivers, each with 5 x 7cm cones and a tweeter. Rated 48Hz to 30KHz. The sub has a frequency control knob that goes from 40 to 180Hz. 1 Link to comment Share on other sites More sharing options...
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