Originally posted by parrydave
sorry for confusing y'all. I'll try again....
I have two amps. Sony 5.1 and an Arcam A85 for stereo. They both use my KefQ35.2s. In my setup, the Left/Right pre-outs from the sony are wired to the Arcam, so the Kefs are driven by the arcam in both 5.1 and stereo.
Now, both amps also use the REL sub. I have a high-level neutrik link from the arcam speaker outs to the REL, plus the LFE pre-out from the sony amp.
In stereo (arcam amp only), I have set the frequency roll off on the back of the REL quite low cos the bass extension from the Q35.2s is quite good. They just need a little extra "thud". On the REL Q150 depending which "mode" you have selected, you can switch the REL's roll-off circuitry in or out of the low-level input route. So the freq. knob on REL only affects the high-level input for my setup. I assume the Quake sub is similar, look at manual.
In 5.1 (sony amp with arcam driving fronts) the LFE feed is controlled by the sony amp, not the REL. The low-level volume knob on REL still sets overall level, but sony amp sets freq. cut offs etc.
The problem I had was that because in 5.1 both my amps are used, the sub gets both low and high level signals. If you are not careful the front L/R bass content doubles up. If you don't route your 5.1 front signals through your stereo amp, this won't be a problem for you. If you do, I came up with 2 solutions:
1) set the fronts as "SMALL" on the sony 5.1 amp, so the L/R pre-outs only send >60Hz, to the arcam. Then the high level from Arcam to the REL is basically removed in 5.1 playback and all bass is handled via the LFE o/p to the REL.
2) The Arcam has two sets of speaker terminals (A/B). Connect the neutrik high level cable to B terminals and KefQ35.2s to A. Both terminals deliver exactly the same so makes no difference to the signal sent to the sub. EXCEPT, when I need to (e.g in 5.1) I can turn speaker B o/p off. Then the REL no longer gets high level feed from Arcam and all front L/R bass is handled by Kef's.
Option 2 works best for me. seems pointless having floorstanders at front, but diverting their bass to a sub when playing movies.
hope that makes sense. It is complicated!
Well. I think you're right - it IS complicated! And I'm glad I'm not the only one who's confused by all this stuff! I have a similar setup to you - an Arcam A75 driving my B&W 602S3 front L/R speakers in stereo, with a Pioneer VSXD812K AV receiver driving the rear (600S3) and centre (LCR60S3) for movies.
The two amps are connected via the Arcam's AV/DVD input and the Pioneer's L/R Pre-outs. The gain is then fixed on the Arcam for 5.1 sound or movies via the 'AV Processor' switch (same as your setup, with the fronts being driven by the Arcam). My sub is an MJ Acoustics Ref 100, connected via a low-level output cable to the Pioneer and a high-level output cable to the speaker terminals on the Arcam stereo amp.
Now, I haven't had this system up and running very long - literally a matter of days - but I have been sooooo confused about this whole hi/lo level thing on the sub. When I emailed MJ Acoustics a while back they re-iterated what was on their site but when I asked about using the SP2 input on the Arcam (like your setup), they didn't recommend doing it that way. I can't recall the reason - I'll try and dig out the email and post it here.
Driving the fronts (B&W 602's) from the Arcam, in normal stereo, with the hi-level input on the sub set to around 60Hz (602's go to about 50Hz) and gain around 10-11 o clock is absolutley fine. Get nice sub-bass. I use the Arcam for playing stereo CDs and vinyl.
When using 5.1 it's a different story. I've found that if I set the crossover on the sub to the 'infinity' (e.g. LFE) setting, I get the sub-bass from 5.1 sources OK (e.g. Pioneer DV656K DVD player, Xbox). However, mixing in even a relatively small amount of gain on the hi-level control results in a mushy mid-range sound! I guess the secret is to not blend too much of this with the LFE or turn it off altogether when using 5.1??? Boy am I confused! I've fired an email over to MJA to see what they say.
As adamsdad has pointed out, the MJ Acoustics site suggests 'mixing' high and low level inputs if possible when watching movies. But I don't like the sound! Unless of course there's something I'm missing...
When I emailed MJ Acoustics a while back and asked about this they re-iterated what was on their site but when I asked about using the SP2 input on the Arcam (like your setup), they didn't recommend doing it that way. I can't recall the exact reason (something to do with the sub must be wired in parallel to the speakers) - I'll try and dig out the email and post it here.
I can see why you went for the SP2 option on the Arcam for the high-level cables and I don't mind switching between 60Hz and LFE when switching between stereo and 5.1 sources, but to have a fiddle about with the high-level gain control every time I change between stereo and 5.1 sources is going to be a pain in the a*se!
I've set ALL the speakers on my Pioneer AV receiver to "small" and the sub crossover settings are selectable at 100Hz, 150Hz and 200Hz. The manual for the Pioneer recommends the 200Hz setting if all speakers are set to "small", which I have done.
Methinks this is going be a long thread!
Cheers,
Kipper