MiniDSP 2x4HD used with a high efficiency system

I only get the noise floor when the MiniDSP in in the chain.  I'm going to go back through the DSP setup and reduce gain to see if there is any effect.

I'm using as a xover (hi pass to Oris150 horns and low pass to the woofers) crossing over at 200Hz and a bit of room EQ.  

My chain is PSAudio BHK Signature Pre --> MiniDSP --> Coiencident Frankenstein II 300B --> Oris 150 Horn.  Then additionally MiniDSP --> Crown K2 --> Woofers

I can hear a hiss when the MiniDSP is in the signal chain from the highly  efficient horns. 

belyin…  Thanks for the input.  Yes, if I use only as a low pass on the base cabinets the Oris are dead silent.  I was trying to give them a hi-pass filter to keep the sub 100Hz off the drivers to extend their life.  Good idea on the PS, I'll give it a try.

Out of curiosity, what drivers are you using with your 150's?  I'm trying the new Voxactiv AC-2.6's and really like them.  Which base cabiner are you using?

belyin... Once I get farther into the tuning I'll give you some feedback on the Voxativ AC-2.6 drivers.  I do like very much the AER's but have had a hard time keeping them alive for any reasonable length of time.  I looked at a number of driver options.  The Voxativ line spans from ~ $1.5k/pr to of course $25k/pr much less than the AER DB-2 or 3.  The AC-2.6 is the middle 8" and lists for a sensible $3.7k/ matched pr.  For the base I am using Bert's BD-15 Reference Compact design at present but am considering change.  I really like the transient response of the La Scala "W" horn.

I heard of someone servicing AER in the DC area a while back.  Let me see if I can find the info.  The tolerances of these drivers is very tight.