Re: I Need Advice on Optimal Setup for Ascend Acoustics Sierra Towers with Horizon Ce
What size is your room?
Description (e.g. is it open on one or more sides)?
Just one SVS sub?
2 channel or multichannel?
What processor/receiver?
As to distance between the Towers, set them up as close to possible as an equilateral triangle with the main listening position. I believe Ascend's general recommendation on distance from rear wall is at minimum equal to port diameter; I'd suggest at least the same from the side walls. (FWIW, mine are about 3 feet out from the rear wall and, due to my room, L is about 12" from side - room is open on that side so front of speaker is where the side wall stops - & R is about 2 feet from side).
As to Toe, try them slightly toed out, straight ahead, and slightly toed in to see what sounds best in your room.
No difference, IMO, on Horizon mounting (stand or shelf) as long as the tweeter is at ear height when sitting (or angled to align with ear height). You'll need to keep some distance from wall (port diameter). Make sure front of Horizon is even with front of stand/shelf or extends slightly beyond (to avoid reflections from shelf/stand if the speaker sits too far back).
As to x-over adjustment, the receiver's room correction will generally set the proper x-over. FWIW, I'm crossing my Towers & Horizon at 60. Unless you like boomy bass, try to avoid putting the subwoofer in a corner. Have you done the sub crawl to decide on sub placement (where bass is best/loudest at MLP)? Sub placement is critical for best response. If you really want to improve bass response throughout the room, add a second sub
* LG OLED65E6P, BenqHT2050A
* Anthem AVM90, Rogue ST100, VTV Pascal 7 ch
* Sierra Towers/Horizon (all ELX RAAL), S2EXv2 surrounds, HTM200SEx4 heights, Rythmik E15HPx2
* VPI Classic 1+ (VTA & Fatboy Gimbal), PE Eagle/RR, VAS NOVA, Soundsmith Paua, Manley Chinook, Bob's Devices SUT, SugarCube 1 mini
* Oppo 203 & 103D, EverSolo DMP-A6
* miniDSP Flex, Audiosensibility & Blue Jeans cables, Symposium & Isoacoustics, GIK
* For RDJ: Anthem MRX720, Sierra LX, Luna Duo v2 center, CXNv2, TBD