Inside StosLabs: Phase 2 Results—and the Road to Phase 3
By Christos “Stos” Tsantilis | Studio design, acoustic tuning & mastering
A studio can look spectacular and still argue with every bass note. At StosLabs, I want the room, the monitors, and the music to get along. Preferably without a lengthy mediation session.
StosLabs is my working studio and test lab, where acoustic design, the custom Velaris One mastering monitors, and a hybrid audio workflow develop together. This case study documents Phase 2: a measured checkpoint in an ongoing project. Phase 3 is ahead, and I’m excited to see how much further we can take it.
Phase 2 at a glance
The REW captures are labelled September 8, 2026. They include separate left-main and right-main measurements, a capture labelled “mono,” individual-driver impulse overlays, and decay analysis. The accompanying report also includes a Rational Acoustics Smaart v8 spectrum display.
Selected left-main, unfiltered REW results: T30 0.222 s; Topt 0.225 s; C50 23.04 dB; C80 30.62 dB; D50 99.5%. These are results for the displayed capture and settings, rather than a specification for every seat or frequency.
Figure 1. The left-main “No Filter” results panel. Click any measurement image to inspect it at full size.
What the decay numbers tell us
Across the displayed one-third-octave bands from 800 Hz to 10 kHz, Topt runs from 0.196–0.234 s for the left main, 0.198–0.237 s for the right main, and 0.203–0.231 s for the capture labelled mono. That is a closely grouped set of mid/high-frequency decay estimates, centred around 0.22 seconds.
The practical aim is to make detail easier to judge: the length of a reverb tail, the relationship between a vocal and its ambience, and the space between notes. Those decisions matter far more than a flattering photograph of the equipment rack—although I do appreciate a good equipment rack.
Figure 2. Left main: frequency-band results. The table shows the variation behind the headline number.
Figure 3. Right main: the same band-by-band view, allowing comparison with the left.
Figure 4. The capture labelled “mono.” Its results are shown separately so the measurement configuration remains clear.
T30 and Topt estimate a 60 dB decay from fitted portions of the measured response. Low-frequency room modes need additional scrutiny with decay, waterfall, and spectrogram views. REW marks potentially unreliable fitted values in orange italics; those flags remain visible in the original captures.
Clarity—with the meaning attached
C50 compares energy in the first 50 milliseconds with energy arriving later. D50 expresses that early energy as a percentage of the total. The left-main figures—23.04 dB and 99.5%—show a strong early-to-late energy relationship in this capture. C80, which uses an 80 ms division and is commonly used for music clarity, reads 30.62 dB.
Early energy includes the direct sound and any reflections inside that time window. These figures therefore do not mean that every early reflection has disappeared. Assessing those reflections also takes time-domain inspection and listening. Good measurements deserve good explanations.
Getting the system to arrive together
Figure 5. Left versus right main: the normalized impulse shapes and principal peaks lie close together at this displayed scale. A precise timing tolerance would require the raw impulse data and confirmed timing-reference settings.
Figure 6. Left-system driver overlays. Different bandwidths produce different impulse shapes, so peak alignment is one part of integration; crossover phase and the summed response matter too.
Figure 7. Right-system driver overlays. Several traces retain repeated working labels from the test session; these should not be interpreted as a definitive driver map.
REW, Smaart, Earthworks—and a lot of listening
My measurement workflow uses Room EQ Wizard, Rational Acoustics Smaart, and an Earthworks measurement microphone. REW lets me inspect impulse response, decay, and frequency-dependent behaviour. Smaart provides real-time spectrum analysis and, when configured for it, dual-channel transfer-function measurements. Each view answers a different question.
Figure 8. The supplied Smaart v8 RTA display. This is a spectrum view, not a transfer-function or phase plot.
Figure 9. Left-main waterfall, with the original window and slice settings visible.
The microphone is part of a complete measurement chain: placement, calibration, signal routing, analysis settings, and repeatability all matter. The supplied REW screens show “SPL uncalibrated,” so their absolute level readings are not presented here as certified sound-pressure measurements. This page documents an in-house development checkpoint, not an independent laboratory certification.
Phase 3: raise the bar, then measure it
Phase 2 gives us a useful baseline for the next stage. The Phase 3 plan is to refine the speaker-room integration further and document the comparison with consistent microphone positions, levels, timing references, and analysis settings. Low-frequency decay, crossover behaviour, early reflections, and the listening area all belong in that next round.
I’m aiming for an exceptional result. The next measurements will tell us what improved and where more work is needed. That is exactly why there is a lab in StosLabs: curiosity has a permanent seat at the console.
The goal stays musical. I want to hear what the artist put into the record, make confident decisions, and help the finished work travel well beyond this room.
— Christos “Stos” Tsantilis
Planning a room of your own?
For studio design, room analysis, speaker integration, or acoustic tuning, use the Contact page and tell me about your room, your monitoring system, and what you need to improve.
Measurement reference notes: REW Help — RT60 Graph and Clarity Graph; Rational Acoustics — About Smaart. Source images: StosLabs Phase 2 reports and alignment captures supplied by Christos Tsantilis.
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