Injecting one sub to Benchmark system…

Your HGC should have two sets of RCA outputs, and one set of XLR output. Use a set left and right of RCA outputs to your subwoofer input. As for economical custom length RCA cables try bluejeans cable.

["kota1 I would get a Dspeaker 8033 which will not only connect it but EQ it for integration with the speakers and your room.’}

In 2005 Velodyne introduced the SPL-R series. Equipped with twelve internal Sweep Tones, six bands of EQ, four alternative EQ Presets, Four position Phase, Volume, Night setting, Auto On/Off and Mute all via Remote Control.

Connectivity via Speaker level Inputs, L/R RCA Inputs and Outputs and Calibrated mic.

thomas, I love mijostyn. His system is terrifically satisfying. Judging by that system and his unbelievably well appointed wood working shop I'd say he has a financial foot up on most of us here. I know I'm envious.

Yes, you can absolutly have excellent bass reproduction at the listening position with one subwoofer.

To the left of the four white RCA outputs on your HGC. The upper two RCA's are labeled L (Left) and the bottom two are labeled R (right). The bottom R output will connect to the red (Right) input of the subwoofer.

Below is the Velodyne SPL-R series Manual

https://www.velodyneacoustics.com/pdf/spl/SPL-UltraSeriesManual.pdf 

Does the layout on the Front Panel Features of your SPL include the (4) MIC input as in the drawing on page 5 of the SPL-R Series Manual? 

There are two different looking Remote Controls both have the same function buttons as the one pictured on page 11 of the SPL Manual. Do you have the Remote Control? 

thomas, SPL 10 RCH doesn’t seem to bring up any information. Though I did find this which may help.

Below is a link to an earlier SPL User’s Manual

https://velodyneacoustics.com/pdf/spl/SPL-RSeriesManual.pdf

The Sub on the cover lacks the Front Panel Features. Notice on page 2 the MIC INPUT (7) is on the back panel. On page 6 the earlier Remote Control is pictured. If these differences match your SPL you may simply need to replace the Remote Control’s battery and purchase a calibrated mic to perform the EQ feature.

Lacking in all Velodyne User’s Manuals until their Plus series is the need to preform the Crawl Test to locate your rooms loudest bass mode where the sub should be located. This is critical for single sub use.

https://www.audioholics.com/home-theater-connection/crawling-for-bass-subwoofer-placement

Velodyne’s onboard EQ is easier to use, far more detailed and includes the four EQ Presets compared to the suggested MiniDSP and DeSpeaker.

FYI, Velodyne Acoustics is now located in Hamburg, Germany.