Not sure of this exists in the home audio arena (found car options).
I'm trying to get a line level sub output from a stereo source before the stereo signal hits the amp.
At this point I've only found a Parasound ZPRE3 that looks like it will work. But I only need one audio input, sub output and the loop out audio output to two channel amp. I don't need a preamp.
Anyone know of if this type of "adapter" exists?

EDIT- Sorry if my explanation above isn't clear.
The signal "flow" would be:
Variable line level analog stereo L/R signal coming from a receiver going to a two channel amplifier. I want to "intercept" the signal before it gets to the amp and feed a powered subwoofer. I guess I could just use two rca splitters to feed both. But, I figured there is a better/ higher quality way to do this.
Hopefully this makes better sense than my first explanation.
Thanks in advance for any help

Look for 'line level low pass crossover' on your browser- Harrison is a company that makes passive crossovers, called FMOD.

https://hlabs.com/

Not likely what any of us considered: Parts Express has a family of low and high pass filters.

Or, an active crossover.

Is this for something that will play only in stereo? Are you going to expect the same components to do what you want and also play surround? You hint at it. Please be explicit.


I've got plenty to say about your next couple of paragraphs but I'll just jump to the end...
Every subwoofer that comes to mind has its own low-pass filter, so if you get yourself a receiver with a "preamp output," I believe you'll have what you want. Feed the preamp output into the sub's line level inputs, adjust the crossover point, set the level, and you're good to go.

Unless you don't want the main speakers to have any of the bass. In that case, you'd do the same thing except your sub's crossover will have to have a high frequency output as well as a low frequency output. The high frequency output would go back into the receiver's amp... but not all receivers with preamp output allow you to actually interrupt the signal before it gets to the main amps.

And this might not work properly if the signal source is digital.

You are asking about one of these:

[Link: dbxpro.com]

Fred,
The buttons labeled "NOT USED" are confusing.

Then there's the fact that the two channels are not labeled the same as one another. Both channels of the thing that OP describes will do the same thing....

Yeah, I admit it, I'm lazy: could you save me from having to read the manual and just suggest what those anomalies are all about?

Didn't consider? The Parts Express photo is exactly what I linked to and I even included 'FMOD' in my post.

It would only be confusing to someone who didn't read the manual or think about how this could be used. Why do you post this kind of stuff? Read the damned manual!

Wouldn't a two channel amp with a sub output be a simpler choice?
Parasound Zonemaster 2350 for instance

Very sorry, your reply is much, much better had not yet posted for me and you can type much faster than I.

depends on what the customer wants to do. Stereo? Mono?

My solution is but one of many. Parasound is a fabulous alternative, done properly...

Would there be a problem using a car audio crossover powered with a 12v wall wart? There are tons of good ones that can be had for very reasonable prices. A good quality one that was always reasonably priced from my car audio days was an MTX RTX01a.

Craig.

Once again, my cat-like reflexes come through............

sorry so late, but why not just use the loop out on the subwoofer?

If the sub offers a line level crossover, this is an option. However, this requires more wires (stereo in/out) to the sub, and there could be some wire length considerations depending on the output impedance of the receiver and sub.