System Optimization – Stirling Trayle, March 23, 2019, by Larry Deniston


During one of the regular SFAS board member discussions regarding ideas for events our members might enjoy, Kevin Olson suggested we consider having Stirling Trayle of Audio Systems Optimized come and talk to us.  Kevin had such a positive experience with Stirling’s services, we felt it was worth a try.  It turned out to be a great idea and a fascinating presentation.  Stirling came to Hilltop and addressed an enthusiastic group of about 60 members.  The following is a summary of Stirling’s presentation.

Stirling’s background:  Stirling started in the audio industry in the 1980s working for Hi Fi shops in the Bay Area, including dB Audio in Berkeley.  Besides sales, one of his jobs was setting up turntables.  In fact, he was the go-to guy for turntable setup and at one point was setting up 40+ turntables and cartridges a month.  Stirling also worked in sales for Transparent Audio and MIT cables.   Then John Hunter of Sumiko approached Stirling and asked him to work for them.  At that time, Sumiko sold primarily cartridges and tonearms, but was a growing business bringing in a number of new products from companies such as Pro-Ject, REL, and Sonus Faber.  After being in sales for a while at Sumiko, Stirling moved to training the sales force to set up systems.   Setting up the small Sonus Faber speakers for good sound was a key part of this training.  After a time, with all of his travels and job changes, Stirling came to realize that he really didn’t care for sales, and setting up systems was what he loved to do.  All of the aforementioned experience gave him the foundation to establish his company, Audio Systems Optimized (

What does Stirling do:  Stirling is not selling any products – he works with his clients’ existing systems to get the best sound possible.  The primary focus of his system optimization work is the reduction or removal of noise.  In stereo systems (Stirling doesn’t work on multi-channel or home theater systems), noise can come from three sources: (1) electrical (wiring and grounding), (2) mechanical (floor, rack and product), and (3) acoustic noise (speaker placement, and floor and room acoustics, including reflection points).

How he does it:  Stirling starts by sending out a questionnaire to his clients which request a description of the system, the room and the AC power supply.  Also included in the questionnaire is a description of the client’s expectation for their listening experience.

Electrical noise:  One of the first things he does is measure the voltage on the safety ground (the voltage between the neutral and ground of the electrical outlet in the room).  This reading should be close to zero and if it’s not, this is a source of electrical noise.  A dedicated circuit will help mitigate this noise source.  If you do plan on running a dedicated line, use twisted wire such as MC clad or “armored cable”.  Romex is not optimal because its wires run in parallel which can cause electromagnetic interference (EMI).  Phono stages are particularly susceptible to electrical noise.  A common solution often cited is “lifting the ground” which is not legal or safe, and therefore is not recommended.  One thing that can help is to have all components plugged into a single power strip that has a star ground system which is plugged into the wall.  This will help avoid potential ground differences which can generate noise.

Mechanical Noise: To address mechanical noise, Stirling starts by taking the whole system apart – everything!  He disconnects all the cables and removes the components.  Then he takes the top off of each piece of equipment and cleans every connection inside the box.  He tightens all screws on circuit boards and equipment tops to ensure they are tight and do not mechanically resonate.  Stirling will check the bolts on the speaker drivers and he’ll take racks apart to ensure everything is tight and evenly tightened.  Then, putting equipment back together, he run the power cables first, keeping them together.  Next, the RCAs are run while ensuring that the RCAs are not running parallel with the power cables.  Stirling fees that cable risers – he uses them if the customer has them – could help depending on the type of cable and whether any carpeting has static electricity.  All of the steps Stirling takes may only represent small, incremental changes, but the effect of all the corrective actions can cumulatively result in a big sonic difference.

Acoustic noise: Stirling addresses acoustic noise primarily through the speaker setup process.  If a client’s room has acoustic treatments, Stirling removes them.  Stirling feels that at times people follow acoustic room treatment guidelines that are better designed for recording studios that require a quiet, “dead” sound.  But this type of treatment is not appropriate for a listening room.  Stirling feels that a room should be lively, not deadened, and that room acoustic issues are best addressed with speaker placement. His approach to speaker setup is not to overtreat a room, but to use speaker placement and interaction with the room to achieve the best sound.  For example, if you visit a room at a trade show that he’s set up, most likely you won’t find any treatment.

Stirling’s approach to speaker setup is a methodical process that can take 10 to 12 hours to complete.  First, he ensures speakers are plumb, then he moves the right speaker off axis, pointing to the wall (still connected and playing music) and begins working on just the left speaker.  Stirling uses this process because it’s easier to focus on one speaker when incremental changes are made.  Speaker placement is done in a “building block” fashion adjusting the speaker in six different planes, one at a time.  He uses a set list of different pieces of music for each stage of the setup, listening for particular sonic characteristics in the music, not the music itself.  Stirling starts with the left speaker close to the back wall and pointing straight ahead.  He then moves his listening position side to side to find the smoothest sound and makes a mental picture of how the speaker looked from that position.  Stirling then sits in the “sweet spot” and toes in the speaker to match how it looked from the position with the smoothest sound.  The next step is to move the speaker forward and back finding the best bass reproduction, then mids and highs.  Then he moves the speaker side to side for the best “live” sound.  So far, we have toe-in and distance from the back and side walls.

Next, Stirling adjusts speaker height one millimeter at a time using the speaker’s spikes.  Stirling commented that it’s amazing how much such a small change can affect the bass response.  Then he proceeds to work on rake angle (the forward and back tilt of the speaker), which affects soundstage height, followed by azimuth adjustment (sideways tilt), which affects the high frequency relationship to the midrange and bass.  Whew, and that finishes the set-up of the just the left speaker!  Then Stirling starts work on the right speaker, using the measured distances from the walls to the left speaker and applying them to the right speaker.  He then performs the same incremental adjustments to the right speaker.  The hardest part, according to Stirling, is getting the rake angle correct for both speakers.  All of this effort puts the speakers in the optimal location in the room yielding the best sonic performance.

Stirling repeated several times that he doesn’t claim that his methodology is the absolute correct or only right way to perform system optimization.  But he’s freely sharing his experience and the process he uses for his clients.

Following Stirling’s talk he responded to questions by attendees.  Here is a short summary:

  • Room treatment – micro reflective panels (micro-perforated panels?) work well for acoustic room treatment.
  • Electronic room correction – Stirling feels it’s better to keep things simple and not put anything extra between the electronics. Plus, some corrections can overdrive amps.
  • Subwoofers – prefers not to use high/low pass filters and allow the speakers to experience the full frequency range from the electronics. He adjusts subs by ear to ensure they fill in the bass appropriately.  A 0.1-degree backward rake angle can clean up bass response.
  • Racks and platforms and reduction of mechanical energy – draining energy effectively depends on the substrate that the energy is drained into. HRS is a good system to address mechanical noise.
  • Equipment, cables and tweaks – use all the same product throughout your system – don’t mix and match.
  • Turntable set up – we ran out of time for this topic, but here are few comments: Alignment is critical for turntables.  Stirling uses the SMARTractor ( for turntables, which has math for Baerwald, Lofgren, Stephenson and the new uni-din alignments.  Cartridge tracking force is also critical for the optimal position of the coil in the flux field.
  • Where to find information – AES papers are a good resource for information – stay away from the blogs.
  • Cleaning metal contacts – Stirling uses Deoxit and Deoxit Gold depending on the material being cleaned. Flitz polishing compound on power cable tangs is also good to use, but proper tools are needed and must be applied with the proper pressure.

This event had the largest attendance we’ve had to date and judging by the positive feedback from our members, it was very well received.   To say this event was a success might be an understatement.

San Francisco Audiophile Society

San Francisco Audiophile Society