Need help with splitting XLR OUTPUT

The Aphex unit suggested by Tls49 does look like an excellent solution, if you don't mind its cost.

Regarding the original question about using cable splitters to split four ways, it depends on the output impedance of the sub output of the Meridian (at deep bass frequencies), and on the input impedances of the JL subs and the Velodyne amps. Unfortunately none of those impedances appear to be specified.

If you want to pursue that approach, contact Meridian and ask them what the output impedance at 20 Hz is for the 861's sub output. Or, alternatively, what is the minimum load impedance they would recommend that it be used to drive.

Also ask JL and Velodyne for the input impedances of the balanced inputs of those units.

To assure good results, the combined (paralleled) input impedances of the JL subs and the Velodyne amps should be at least ten times as great as the output impedance at 20 Hz of the Meridian's sub output. Or, alternatively, the combined (paralleled) input impedances of the JL subs and the Velodyne amps should be greater than the minimum load impedance Meridian may recommend for the 861's sub output.

The combined (paralleled) input impedances of the JL subs and the Velodyne amps equals the reciprocal of the sum of the reciprocals of their individual input impedances ("reciprocal" meaning the number divided into 1). For example, if the input impedances are 10K for the Velodyne amps and 15K for the JL subs, their combined input impedance is:

1/(1/10 + 1/10 + 1/15 + 1/15) = 3K, or 3,000 ohms

Regards,
-- Al

I use a pair of Velodyne HGS-15s with an SMS-1 bass manager. All the connections of the Cary 11a, SMS-1, and the two subs are XLR. Velodyne suggested I just split the XLR output of the SMS-1 to the two subs. It's an easy solution and the one I'm using, but I wonder if it's the best solution. OTOH, it seems to work well.

db

DB, again the impedances of the Velodyne components don't appear to be specified, but nevertheless I see no particular reason to suspect that the two-way split would be an issue. The SMS is solid state, meaning that there is relatively little likelihood that it would have an inordinately high output impedance at deep bass frequencies; possible effects on mid and high frequencies would not matter; the fact that the interconnections are balanced minimizes the likelihood of ground loop and noise-related issues; Velodyne recommended the solution; and it appears to work well.

Regards,
-- Al

Thanks for your help. I just ordered the Aphex unit. I was concerned about splitting the signal after the Velodyne amps since they are all SC1250 units and would send a corrected signal out to the JL Audio Gotham Subs of which they have their own computerized setups as well. My preamp, the Meridian 861 v8 also utilizes room correction, so I am trying to split out a pure subwoofer out signal to each before any processing of the signal is done by any of the components. Since I also use a pair of Meridian 8000 speakers where the woofer/subs in them utilize room correction as well, i figured going with your recommendations of the Aphex. My system is rounded out with the Meridian 7200 center channel and 4 of the Meridian 5300 speakers.
Thanks again for all of your help.

Thanks, Al. I think I'll leave well enough alone as you suggest.

Oppo told me that 0.1 is sent to the subs regardless of the settings for the speakers, so I use the stereo output for the LR front of 7.1, because Oppo gives stereo special analog processing. I need to set the LR mains to large, because XLR analog stereo does not include bass management, but any crossover is applied. The KEF 107/2 mains extend to 20 Hz nicely with the KUBE, so subs are not really needed for music. But they shook the room when we played Life of Pi.

db