Spatial Audio Raven Preamp

The Raven will have no trouble driving an RCA output at the same time as XLR.  This has been tested by Spatial.  You should have no problem except that the XLR output is higher level than the RCA.  That is as it should be.  If your subwoofer amps have gain controls you should be able to match levels.  Subs are always tricky.  The other option is speaker level outputs to drive stereo subs near the main speakers.  That is the way I have always done it, but thankfully, my current speakers easily play 30 Hz in room so I no longer use subs.

I should add that all folded bass horns are tricky beasts. They only exist because a true straight bass horn that is flat to, say, 35 Hz, would be the size of medium-sized car. In other words, the size of an adjacent room. Two needed for stereo, of course.

PWK compromised with the real world by folding the horn (which creates internal reflections) and using the room corners to expand the size of the horn mouth. The internal reflections create ripples in the response above 150 Hz, and the cutoff region has +/- 5 dB ripples in the response, which interact with the room modes.

This is why adding a subwoofer is kind of tricky. You have to integrate not two, but three things: the Khorn response in its cutoff region (which is definitely not flat), the built-in filter of the subwoofer amp, and the room modes. Having two (or more) subwoofers is very useful because the room modes for one subwoofer will be at different frequencies than the other subwoofer, which smoothes out both of them. It’s also why multiple small subwoofers, in widely spaced locations, is a much better choice than a single subwoofer.

I should add the Khorn horn cutoff might be a lot higher than Klipsch says it is. 60~70 Hz would not surprise me.

@lynn_olson

Bam!

Thank you! One sub added. (Old one kept just in case) and will get another. Much better sound experience right away. The pre/system sounded aok with no discernible difference after putting cable into Pre’ Amp’s RCA output. Thought I could do as much but waited untill one of the birth fathers chimed in.

Sub set around 50Hertz. Will mess wi/ setting up/down.

Another round of thanks. 

@wsrrsw

Good, sounds like you are on the right road. Subs are tricky. Good luck. I am sure you are getting some nice imaging and very real sounding instruments with great dynamics. Klipsch and bass... well...... that is not their strong point (but I didn’t say that out loud)

@donsachs

Quick question.  My speakers are 90dbs, can your 300b mono blocks give me, say 85db of sound?

Thanks in advance.