측정을 믿어도 되는 이유Why the numbers can be trusted

측정기의 신뢰성은 화면이 예뻐서 생기지 않습니다. CAA는 정답을 이미 아는 신호를 실제 제품과 똑같은 코드에 넣고 답이 맞는지 확인합니다 — 정확히 5.000 ms 지연된 스윕, 잔향시간이 정확히 500 ms인 감쇠, 2.46%와 0.49%의 고조파를 갖도록 만든 왜곡. 아래 표는 그 결과이고, 숫자는 손으로 적은 것이 아니라 검증 프로그램이 출력한 그대로입니다.A measurement tool is not trustworthy because its screens look good. CAA is fedsignals whose answer is already known — a sweep delayed by exactly 5.000 ms, a decay whose reverberation time is exactly 500 ms, a distortion built to have harmonics of 2.46% and 0.49% — through the same code the product ships. The tables below are what came back, printed by the test program rather than typed out.

241개 항목 · 실패 0개241 checks · 0 failing

빌드할 때마다 이 검증을 다시 돌립니다. 하나라도 틀리면 그 빌드는 나가지 않습니다.The suite runs on every build. If one check fails, that build does not ship.

REW와 나란히 측정한 결과Measured beside REW

같은 임펄스 응답 파일을 CAA와 REW V5.40에 각각 넣고 읽은 값입니다. 이론값은 필터 계수와 감쇠식에서 직접 계산한 정답입니다. 크로스오버 응답은 53 dB 아래까지 0.02 dB 이내, 잔향시간은 0.8% 이내로 일치합니다.The same impulse-response files, measured in CAA and in REW V5.40. The theory column is the exact answer from the filter coefficients and the decay law. The crossover response agrees to within 0.02 dB even 53 dB down, and the reverberation times to within 0.8%.

항목Measurement이론값TheoryCAAREW차이CAA − REW
LR4 2.5 kHz, 1 kHz-0.213-0.213-0.213-0.000
LR4 2.5 kHz, at fc-6.021-6.024-6.019-0.005
LR4 2.5 kHz, 5 kHz-25.516-25.512-25.504-0.008
LR4 2.5 kHz, 10 kHz-53.397-53.400-53.377-0.022
T20, 500 ms decay500.000502.728498.850+3.878
T30, 500 ms decay500.000499.931499.172+0.759
C504.7444.8104.742+0.068
C809.0969.1768.945+0.231

단위는 항목별로 dB 또는 ms입니다. REW는 REST API로 같은 파일을 불러 측정했고, 재현에 쓴 스크립트는 rew_compare.py에 들어 있습니다.Units are dB or ms per row. REW measured the same files through its REST API; the script that does it is rew_compare.py.

검증 항목 전체Every check

레벨 스케일Level scale (WebAnalyser) · 2
항목check측정measured이론expected허용tol
sine, summed bin power vs -20 dBFS RMS-20-20.00000.1PASS
white noise, summed bin power vs RMS-16.8236-16.80340.1PASS
밴드 표와 A 가중Band tables (ISO 266 / IEC 61672) · 21
항목check측정measured이론expected허용tol
31-band table size3131.00000PASS
band 0 = 20 Hz2020.00000PASS
band 17 = 1 kHz10001000.00000PASS
band 30 = 20 kHz2000020000.00000PASS
A-weighting @ 31 Hz (class 1)-39.49-39.50001.5PASS
A-weighting @ 31 Hz (tight)-39.49-39.50000.12PASS
A-weighting @ 63 Hz (class 1)-26.2551-26.20001PASS
A-weighting @ 63 Hz (tight)-26.2551-26.20000.12PASS
A-weighting @ 125 Hz (class 1)-16.219-16.20001PASS
A-weighting @ 125 Hz (tight)-16.219-16.20000.12PASS
A-weighting @ 250 Hz (class 1)-8.7002-8.70001PASS
A-weighting @ 250 Hz (tight)-8.7002-8.70000.12PASS
A-weighting @ 500 Hz (class 1)-3.2698-3.20001PASS
A-weighting @ 500 Hz (tight)-3.2698-3.20000.12PASS
A-weighting @ 1000 Hz (class 1)-0.00020.00000.7PASS
A-weighting @ 1000 Hz (tight)-0.00020.00000.12PASS
A-weighting @ 2000 Hz (class 1)1.27041.20001PASS
A-weighting @ 2000 Hz (tight)1.27041.20000.12PASS
A-weighting @ 4000 Hz (class 1)1.25911.00001PASS
A-weighting @ 8000 Hz (class 1)-0.447-1.10001.5PASS
A-weighting @ 12500 Hz (class 1)-4.4105-4.30002PASS
스윕 디컨볼루션 · 도달 시간Sweep deconvolution -- arrival time · 5
항목check측정measured이론expected허용tol
0 samples -> 0.000 ms00.00000.005PASS
240 samples -> 5.000 ms55.00000.005PASS
240.5 samples (sub-sample)5.01045.01040.02PASS
961.3 samples (sub-sample)20.024720.02710.02PASS
inverted input -> negative impulse peak11.00000PASS
크로스오버 · 설계와 실측Crossover -- designed and measured back · 16
항목check측정measured이론expected허용tol
LR4 low-pass at fc-6.0206-6.02000.1PASS
LR4 high-pass at fc-6.0206-6.02000.1PASS
Butterworth 24 dB/oct at fc-3.0103-3.01000.1PASS
Butterworth 6 dB/oct at fc-3.0103-3.01000.1PASS
Butterworth 12 dB/oct at fc-3.0103-3.01000.1PASS
Butterworth 18 dB/oct at fc-3.0103-3.01000.1PASS
Butterworth 24 dB/oct at fc-3.0103-3.01000.1PASS
Butterworth 30 dB/oct at fc-3.0103-3.01000.1PASS
Butterworth 36 dB/oct at fc-3.0103-3.01000.1PASS
Butterworth 42 dB/oct at fc-3.0103-3.01000.1PASS
Butterworth 48 dB/oct at fc-3.0103-3.01000.1PASS
measured vs designed @ 200 Hz-0.0004-0.00030.3PASS
measured vs designed @ 1000 Hz-0.2135-0.21310.3PASS
measured vs designed @ 2500 Hz-6.0241-6.02060.3PASS
measured vs designed @ 5000 Hz-25.5121-25.51550.3PASS
measured vs designed @ 10000 Hz-53.3995-53.39710.3PASS
고조파 왜율Harmonic distortion (Farina packets) · 4
항목check측정measured이론expected허용tol
distortion analysis valid11.00000PASS
H2 @ 1 kHz2.4632.46310.25PASS
H3 @ 1 kHz0.49260.49260.15PASS
THD @ 1 kHz2.51182.51180.3PASS
실내 음향 (ISO 3382-1)Room acoustics (ISO 3382-1) · 7
항목check측정measured이론expected허용tol
T20 of an exact 500 ms decay502.7281500.000015PASS
T30 of an exact 500 ms decay499.9307500.000015PASS
T30 regression fit r^21>=0.99000PASS
C50 vs closed form4.814.74370.5PASS
C80 vs closed form9.17649.09560.5PASS
octave-band T30 @ 125 Hz (700 ms)700.0123700.000060PASS
octave-band T30 @ 4 kHz (250 ms)250.0031250.000040PASS
NC 등급NC rating (noise criterion) · 3
항목check측정measured이론expected허용tol
spectrum on the NC-30 line3030.00000PASS
6 dB quieter rates better than NC-305>=1.00000PASS
6 dB louder rates worse than NC-3010>=1.00000PASS
2채널 FFT 전달함수Dual-FFT transfer function (IRMeasurement) · 10
항목check측정measured이론expected허용tol
result produced (unfiltered)11.00000PASS
delay of an exact 8.000 ms path88.00000.05PASS
result produced (filtered)11.00000PASS
H1 magnitude vs design @ 500 Hz0.0095-0.01340.6PASS
H1 magnitude vs design @ 1000 Hz-0.183-0.21310.6PASS
H1 magnitude vs design @ 2500 Hz-6.0346-6.02060.6PASS
H1 magnitude vs design @ 5000 Hz-25.4711-25.51550.6PASS
delay added by the LR4 itself0.18750.18000.03PASS
coherence in the pass band (500 Hz)0.9999>=0.95000PASS
coherence in the stop band (12 kHz) is low11.00000PASS
최소위상 · 초과위상Minimum / excess phase · 5
항목check측정measured이론expected허용tol
decomposition valid11.00000PASS
LR4 alone: excess delay is zero00.00000.02PASS
pure 2.000 ms delay22.00000.02PASS
LR4 + 2.000 ms: delay separated from filter22.00000.03PASS
minimum phase reproduces the LR4's phase0.08980.00002PASS
채널별 목표와 점수Per-channel target and score · 26
항목check측정measured이론expected허용tol
target curve built240240.00000PASS
perfect response scores 10099.9145100.00000.5PASS
tweeter is judged from ~3.1 kHz up3149.80253149.75005PASS
perfect response needs no fixes00.00000PASS
a uniformly quiet channel loses half its score49.985350.00001PASS
score follows RMS deviation82.5182.51000.1PASS
a real error costs points17.49>=5.00000PASS
worst band identified31503150.00000PASS
correction has the right sign and size-3.5-4.00001.5PASS
correction never overshoots the error0.5>=0.00000PASS
a spike narrower than the band is under-corrected0.5>=0.00000PASS
sub is judged below its corner63.49663.49711PASS
out-of-band content does not change the score98.363998.36390.01PASS
band read back from a 2.5 kHz high-pass2181.55352500.0000500PASS
...and it reports no low-pass00.00000PASS
band-pass low corner400.7899400.000080PASS
band-pass high corner2278.41992500.0000500PASS
sub low-pass corner83.882580.000016PASS
...and no high-pass on a sub00.00000PASS
a full-range driver reports no corners00.00000PASS
summed target built240240.00000PASS
the gap between two drivers is in the target24.1952>=10.00000PASS
a single spanning band would have missed it29.1664>=10.00000PASS
one driver sums to itself00.00000.01PASS
a tweeter with no crossover set still has a band25002500.00000PASS
a sub with no crossover set still has a band8080.00000PASS
AUTO 모드 순서AUTO mode sequence · 14
항목check측정measured이론expected허용tol
the guided sequence exists1919.00000PASS
the crossover is set before any sweep7>=1.00000PASS
time alignment comes before any EQ4>=1.00000PASS
per-channel tone before the global EQ5>=1.00000PASS
per-channel tone after the crossover is set6>=1.00000PASS
per-channel tone before time alignment1>=1.00000PASS
the channel-target step needs no loop-back11.00000PASS
the step opens the Channel Target screen11.00000PASS
a car that measures right passes11.00000PASS
every channel is reported22.00000PASS
a badly-off channel blocks the step11.00000PASS
the failing channel is named first11.00000PASS
with a band and an amount to change11.00000PASS
no measurement is a warning, not a pass11.00000PASS
위상 · 지연 램프 · 시간 기준Phase, delay ramp and timing reference · 7
항목check측정measured이론expected허용tol
bin spacing of a 16384-point FFT2.92972.92970PASS
the last bin is Nyquist2400024000.00000PASS
a tiny transform too2400024000.00000PASS
a 5 ms delay wraps every 200 Hz32.00001PASS
wraps crowd together toward the top22>=15.00000PASS
removing the delay leaves flat phase00.00001PASS
half a sample of error is visible59.9963>=25.00000PASS
C 가중 (IEC 61672-1)C-weighting (IEC 61672-1) · 10
항목check측정measured이론expected허용tol
C-weighting @ 31 Hz-2.9875-3.00001.5PASS
C-weighting @ 63 Hz-0.8508-0.80001PASS
C-weighting @ 125 Hz-0.2011-0.20001PASS
C-weighting @ 250 Hz-0.02410.00001PASS
C-weighting @ 500 Hz0.01540.00001PASS
C-weighting @ 1000 Hz00.00000.7PASS
C-weighting @ 2000 Hz-0.1038-0.20001PASS
C-weighting @ 4000 Hz-0.5346-0.80001PASS
C-weighting @ 8000 Hz-2.3518-3.00001.5PASS
Z-weighting passes the signal untouched00.00000PASS
마이크 보정 파일Microphone calibration file · 8
항목check측정measured이론expected허용tol
calibration file loads11.00000PASS
no correction where the mic is flat00.00000.01PASS
a +6 dB mic error corrects by -6 dB-6-6.00000.01PASS
interpolated between points-2.9998-3.00000.3PASS
flat outside the file's range-6-6.00000.01PASS
spectrum corrected at 10 kHz-5.9997-6.00000.05PASS
spectrum untouched at 1 kHz00.00000.05PASS
cleared calibration corrects nothing00.00000PASS
샘플레이트별 필터 안정성Biquad stability across sample rates · 6
항목check측정measured이론expected허용tol
worst pole margin below the unit circle0.0009>=0.00000PASS
20 kHz section on a 32 kHz device stays bounded0.95651.00002PASS
...and its impulse response decays away00.00000PASS
48 kHz / 1 kHz untouched10001000.00000.01PASS
48 kHz / 20 kHz untouched20000.000920000.00000.01PASS
32 kHz / 20 kHz clamped below Nyquist15680.001115680.00001PASS
임피던스 · 유닛 모델의 공진Impedance -- resonance from a driver model · 7
항목check측정measured이론expected허용tol
a resonance is found11.00000PASS
Fs recovered from the curve44.955245.00001.5PASS
the plain maximum really is the inductive rise20000>=10000.00000PASS
Z_min is close to Re6.07086.00000.6PASS
a tweeter's Fs too894.9113900.000025PASS
Fs survives 4% ripple on the curve44.877645.00002.5PASS
a resistor reports no resonance11.00000PASS
스윕 품질 · 클리핑과 SNRSweep quality -- clipping and SNR · 12
항목check측정measured이론expected허용tol
0.95 peak flagged as input overload11.00000PASS
0.50 peak is not00.00000PASS
pre-roll does not shift arrival (240 smp -> 5.000 ms)55.00000.005PASS
SNR of a take with noise 40 dB under the sweep82.321582.19861.5PASS
reverb tail is not counted as noise120>=50.00000PASS
hum: 1 kHz band clearly above the 63 Hz band63.0209>=20.00000PASS
hum: 1 kHz band itself is clean74.7622>=40.00000PASS
averaging 2 takes gains about 3 dB SNR3.13023.00001PASS
clipped take: lower the output-1-1.00000PASS
quiet, noisy take: raise it11.00000PASS
raise by enough to reach -12 dBFS2020.00000.01PASS
a good take: leave it00.00000PASS
AI 어시스트 진단 규칙Tuning assistant (offline rules) · 25
항목check측정measured이론expected허용tol
no data -> no items00.00000PASS
inverted first peak -> polarity rule11.00000PASS
clipped take -> overload rule11.00000PASS
narrow -8 dB notch -> 'don't EQ' rule11.00000PASS
...and no boost suggestion for it00.00000PASS
symptom matched (쏠려요)11.00000PASS
spelling variant -> same symptom11.00000PASS
unrelated question -> honest no-answer11.00000PASS
...offering 3 nearby symptoms33.00000PASS
tweeter HPF 800 Hz / 12 dB -> warned11.00000PASS
tweeter HPF 2.5 kHz / 24 dB -> quiet00.00000PASS
sub LPF 160 Hz -> warned11.00000PASS
mid ends 2 kHz, tweeter starts 4 kHz -> gap11.00000PASS
mid to 3.5 kHz, tweeter from 1.8 kHz -> overlap11.00000PASS
matched 2.5 kHz handover -> neither00.00000PASS
+8 dB EQ boost -> warned11.00000PASS
band at -12 dB rail -> flagged11.00000PASS
correction added a 7 dB bump -> 'worse after'11.00000PASS
bump removed by correction -> 'better after'11.00000PASS
R 6 dB louder at 1 kHz only -> L/R colour rule11.00000PASS
identical L/R -> quiet00.00000PASS
'트위터 터질까 봐요' -> tweeter_safe11.00000PASS
'보컬이 멀게 들려요' -> vocal_far11.00000PASS
'저음이 트렁크에서 들려요' -> sub_where11.00000PASS
'보정했더니 더 이상해요' -> after_worse_q11.00000PASS
EQ 추천 = 실제 적용 필터EQ fit -- recommendation equals the applied filter · 16
항목check측정measured이론expected허용tol
+3 dB band reads +3 dB at its centre33.00000.01PASS
63 Hz peak +5 -> band gain-4-4.34970.5PASS
1 kHz peak +4 -> band gain-2.9-3.34970.5PASS
8 kHz dip -2 -> band gain32.65030.5PASS
residual after fit0.38580.00000.5PASS
re-measure round changes nothing00.00000.3PASS
boost capped at +3 dB (3 - max)0>=-0.00100PASS
cap reported11.00000PASS
narrow dip reported11.00000PASS
dip centre1974.02992000.0000100PASS
no boost into the dip (-gain @2k)0>=0.00000PASS
tweeter passband low edge1810.19341900.0000400PASS
tweeter: nothing below 1.6 kHz00.00000PASS
tweeter: no boost at/below its corner00.00000PASS
tweeter: 6.3 kHz bump taken out-4.3991-4.00001PASS
band count respected11.00000PASS
세션 파일 · 형식 2 왕복, 형식 1 변환Session file -- format 2 round trip, format 1 migration · 15
항목check측정measured이론expected허용tol
format 2 loads11.00000PASS
format recorded22.00000PASS
magnitude bit-exact (bin 1023)00.00000PASS
before-take kept separately33.00000PASS
Live EQ band survives-3.4-3.40000PASS
EQ on flag survives11.00000PASS
recommend round survives22.00000PASS
Korean title survives11.00000PASS
crossover corner survives63.563.50000PASS
crossover slope + type survive11.00000PASS
crossover PEQ survives-2.5-2.50000PASS
format 1 still loads11.00000PASS
format 1: channel delay read3.53.50000PASS
format 1: no before-takes00.00000PASS
format 1: no corrections00.00000PASS
AUTO · 시작 점검, 재측정, 진행 저장AUTO -- start checklist, re-measure, saved progress · 8
항목check측정measured이론expected허용tol
first step is the start checklist11.00000PASS
an unprepared car: warned, not blocked11.00000PASS
checklist lists six items66.00000PASS
a prepared car passes11.00000PASS
re-measure recognised (residual wording)11.00000PASS
converged re-measure passes11.00000PASS
AUTO step survives the session file77.00000PASS
step verdicts kept by step id11.00000PASS
라이브 EQ · 들리는 소리 = 화면 곡선Live EQ -- what plays equals what is shown · 6
항목check측정measured이론expected허용tol
48 kHz: heard vs shown, worst point0.00410.00000.05PASS
44.1 kHz: heard vs shown, worst point0.01990.00000.05PASS
curve set before the device opened0.01990.00000.05PASS
device changed 48 -> 44.1 kHz0.01990.00000.05PASS
flat curve passes samples unchanged11.00000PASS
all bands at +/-12 dB stay stable11.00000PASS
Target score -- the system's shape, not the signal'sTarget score -- the system's shape, not the signal's · 4
항목check측정measured이론expected허용tol
perfect system, pink noise per bin99.6562100.00000.5PASS
perfect system, mic minus source99.7679100.00000.5PASS
level does not change the score-0.23210.00000.5PASS
1 kHz dip costs points, not the whole score92.339792.00006PASS
Room acoustics -- impulse-to-noise (when T20/T30 can be trusted)Room acoustics -- impulse-to-noise (when T20/T30 can be trusted) · 4
항목check측정measured이론expected허용tol
noise -30 dB -> INR read back29.740629.70471PASS
noise -50 dB -> INR read back49.700249.70471PASS
INR 30 dB: T20 flagged11.00000PASS
INR 50 dB: T20 and T30 trusted11.00000PASS

직접 확인해 보기Check it yourself

위의 두 표는 계산을 검증한 것입니다. 마이크와 차량까지 포함한 진짜 측정은 각자의 장비로만 확인할 수 있으므로, 그 절차와 도구를 함께 넣어 두었습니다. 같은 마이크를 같은 자리에 고정한 채 한 채널을 CAA로 한 번, REW로 한 번 재고field_compare.py를 돌리면 두 곡선과 차이 곡선이 나옵니다. 절차와 결과 읽는 법은 FIELD-COMPARE.md에 있습니다.The two tables above check the arithmetic. Whether a real measurement through your microphone and your car agrees can only be established on your own rig, so the procedure and the tool ship with the app. Fix one microphone in one place, measure one channel once in CAA and once in REW, and run field_compare.py: it draws both curves and the difference between them. The method, and how to read the result, is inFIELD-COMPARE.md.

아래 그림은 그 대조 도구가 스스로 만들어 내는 오차입니다 —같은 임펄스 응답 파일 하나를 CAA 세션과 REW에 각각 넣고 비교한 것으로, 평균 0.007 dB, 최대 0.054 dB(16 kHz)입니다. 실측에서 이보다 큰 차이가 나온다면 그것은 도구가 아니라 측정 조건입니다.The picture below is the error the comparison tool itself contributes: one and the same impulse response put through a CAA session and through REW, differing by 0.007 dBon average and 0.054 dB at worst (at 16 kHz). Anything larger in a real comparison is the measurement conditions, not the tools.

CAA and REW on the same impulse response

이 검증이 말하지 않는 것What this does not prove

여기서 확인한 것은 계산이 맞다는 것입니다. 측정 전체의 정확도는 마이크와 인터페이스에도 달려 있습니다. 절대 음압(dB SPL)은 교정기(calibrator)로 마이크를 맞춘 만큼만 정확하고, 교정기가 없으면 상대값 — 채널 간 레벨 차, 도달 시간 차, 극성, 응답 모양 — 만 유효합니다. 다행히 DSP에 넣는 값은 모두 그 상대값입니다. CAA는 공인 교정 성적서를 발급하는 계측기가 아니며, 그런 용도로 쓰면 안 됩니다.What is established here is that the arithmetic is right. The accuracy of a real measurement also depends on the microphone and the interface. Absolute sound pressure is only as good as the calibrator used to set the microphone up; without one, only relative figures hold — level differences between channels, arrival-time differences, polarity, the shape of a response. Those happen to be every number you type into a DSP. CAA is not a certified instrument and must not be used as one.