Changes that made a difference (in order of effect).

Here are the changes I’ve made to my system in the last six months -

Speaker placement: I’ve been moving my SF Auditor M’s around trying to get the best imaging and smoothest frequency response. They are currently 30” from the front wall, 67” from the side, 76” apart, and toed in ~ 15 degrees. I have moved them back and forth in all directions as well as shifted my seating position trying to optimize the room/ speaker interaction. This is a very time consuming study. REW software helped; being able to see changes in distortion, time domain and frequency response makes it less ambiguous. It now feels like it’s as good as it’s going to get. BTW, the mad NASA engineer was right. Speakers closer together, closer than you might otherwise think, is better.

Diffusor: I built the Arqen lean diffusor designed by Tim Perry and put it on the near side wall to improve clarity. (Unfortunately, my room set up is not symmetrical.) I have lots of constraints in my mixed use living/ listening room. So a diffusor doubling as wall art is a win/ win situation. (See photo in my virtual system.) Initially, I tried the model 4 but in the end I went with the flat version. Moreover, I made it out of walnut and reduced the height to 13” instead of the recommended 48” for improved WAF.

The “Master Handbook of Acoustics” recommends absorption at the first reflection point and Floyd Toole recommends nothing on the wall at the FRP. Recommendations also vary depending on whether it’s a studio control room or a listening space. The diffusor is 8’ from my listening position. I don’t know if the lean diffusor is actually diffusing or just attenuating. What is noticeable is how much clearer China Forbes’ voice is when playing Pink Martini. YMMV

Preamplifier clipping: This issue is discussed at length in the Harbeth user group. http://www.harbeth.co.uk/usergroup/forum/the-science-of-audio/amplifier-matching-mismatching-and-cli... Willemj pointed me in that direction a while back. Previously, my volume setting was around 9 o’clock for ~70 dB sound level, not much useable range on the volume dial. I added -10dB attenuation to my Marantz CD player (one of the default settings) and that shifted the volume setting upward to around 11 o’clock. Previously, listening to Jeff Buckley’s “Hallelujah” there were two points in the song where the guitar goes twang and my ears would go Ouch! Now, much better.

Wall outlet: This is a tweak that others swear by but I can’t be sure of. After seeing what extreme measures Folkfreak went to manage his incoming power, I wondered about my standard residential set up. I unscrewed the old back stab wall socket that my system is plugged into and pulled on the wires. They easily slipped about 1/8” before grabbing. Hmmm...not a very positive connection. I replaced it with a Hubbell 8300H (old un-plated version) I got on eBay. It seemed like the bass response was better (maybe) but I couldn’t confirm by A/B testing the outlets. 1) it takes at least 10 minutes to replace a socket (too long to remember) and 2) I cannot recreate the 30 year old marginal connection to the back-stab outlet. In any event, I’m happy with the very positive connection provided by the Hubbell plate and screws.

I’m done (for now). These positive changes are mostly from shared learnings by forum members for which I’m grateful.

What recent changes have you made to improve the sound of your system?