Sub connection to CARY SLP-05 preamp

No problem at all, Amfibius. I have put up a pair of speaker cable to the sub from amp tonight, it seems working quite good now. I found the xover at 53hz quite fit to my speaker, still tweaking.... just wondering what it means by tweaking those SLOPE things...., there are LOW PASS XOVER SLOPE, SUBSONIC FREQ, SUBSONIC SLOPE, PHASE, CONTOUR FREQ, CONTOUR LEVEL. Nothing from the manual....

BTW, thanks for the help from Almarg! Thumbs up！Music is so much involving now.....

Here you go Cary's reply.....Any thoughts?

Richard.



The best thing to do would be to run a pair of cables from the second pair on main outputs to you subwoofer. Do not use a Y-adapter to a mono sub input. The connections should be stereo (R/L) connections.



The outputs are capacitor coupled but the positive phase from the XLR is shared with the RCA positive signal. They are not isolated from each other. This type of subwoofer setup is done a lot with our equipment and unless there is a very low input impedance at the amplifier inputs, like 10K or below you shouldn’t have any issues doing this. The SLP-05 has plenty of gain to drive this.



Hope this helps!



Dan Wemmer

Technician

CARY AUDIO DESIGN

The Cary person provided excellent information. However, as I see it the information he provided makes the case for connecting via speaker-level much more compelling.

Since the positive polarity xlr signal and the rca signal are common, if you were to connect the xlr output to the main power amp and the rca output to the sub, that signal would have a load of 9.4K (see the calculation in my previous post), which would violate the 10x rule by a wide margin, and would also violate the 10K criterion Mr. Wemmer specified.

There would be other downsides to doing that, as well. At low frequencies the balanced inputs to your main amp would no longer be balanced, in terms of the amplitudes of the two signal polarities. There would also be a significant impedance imbalance on the two polarities, which would substantially degrade the noise rejection capability of the balanced interface to your main amp.

The good results Amfibius has obtained with that configuration are, I suspect, attributable to having considerably higher input impedances on both his amp and his sub. I don't know what the input impedance of his JL Audio sub is, but I see that the balanced input of his CAD-211AE amp is specified as 91K.

Best regards,
-- Al

Grandtech,

Are you using a video monitor to view response during the set-up tone sweeps?

If so, you can see the impact of adjusting any of those controls. As you adjust them, the change in the output of the sub will be reflected on screen. Once you see the change, you can listen for it. In my case, most changes were clearly audible, tho sometimes an adjustment that produced a visible result did not produce an audible result (that I could detect, anyway).

Fine adjustment of phase may help reduce some response anomolies prior to EQ and therefore reduce the amount of EQ you'll need to "fix" the response. Similarly, you can adjust placement of the subs while viewing response to the same end - optimal placement reduces the amount of EQ needed. That way, you'll be able to "surgically" use those 8 bands to get really smooth bass response. A mammoth PITA, but worth the effort.

The slope and level controls are essential to acheiving smoothest hand-off from main to sub. That one you will see and hear.

Marty

BTW, if the software hasn't been updated since I bought my SMS-1 (it's been +/- 3 years, so this may or may not still be true):

I would strongly advise against just using the AUTO EQ function. It does not even begin to utilize the parametric capabilities in the sub and you can do much, much better via manual adjustment w/ the video readout, per the above.

Good Luck,

Marty