preamplifier after preamplifier?

Preamp? Overkill.

Just insert one of these.to the sub feed.

Then you have RC at the listening position.

I do.

All else is blather including 2 remotes, har har funny.

I've got TV, cable box, BluRay, AVR, HiFi pre amp, DAC, SHD Studio selector, subwoofer level and headphone amp on ONE $8 programmable remote.  Plus a Windows PC remote I don't use anymore is on it.

He is saying his subs are active or powered. A passive sub usually has an onboard XO, but there is Debra, Swarm designs that run 1-4 subs per amp and the amp has the low pass filters and settings. Dayton 1000s are very popular, run one or two.

I use a DCX2496, just for the convenience and ease to add a passive subs or bass column (up to 6 and the controller is daisy chainable 128 nodes). Heck I can even add a rumble filter for TT use or use it as a band pass for my Bass columns. 100-300hz and it has zero effect on GRs OB servo sub DBA I use from 100hz and down.

MY point is simple if all your drivers are matched pretty close including the subs, turning the volume up or down is usually ok with most systems. When you have KHorns. or Corner horns, or La Scala, you'll understand what the OP is probably talking about IF you had most subs.

The speaker efficiency don't jive, can you dig it? 100%+ efficient main speakers with 85% subs don't work. For ME!. They might for you. :-) That would drive me completely bonkers, my wife would go nuttier than she already is, bouncing up and down to match subs. AND she would, trust me.

Maybe I'm to picky. :-)

Regards

@flemmingss - Sure, what you have diagrammed will work. It will give you the independent control of relative level that you want.

You don't need another preamp just a passive volume knob. Here's one: Amazon.com: Nobsound High Precision Passive Preamp Volume Controller VOL Control HiFi Preamplifier ALPS (RCA&HiFi Version, Black) : Electronics

You could bet a Parasound P7 which has this built in. So does the 5 and 6.