PA Sub Shootout 2021

Описание: Enjoy this roundup of most of my subwoofer measurements of 2021.

Measurement equipment, methodics, environment:

Software: ARTA, STEPS & LIMP
Soundcard: Creative X-Fi USB HD
Pre-Amp: IMG MPA-102
Microphone: Isemcon EMX-7150 (Class 1 FR; calibrated; Max. SPL 135 dB @ 1% THD)
SPL Calibrator: Isemcon SC-1 (Class 2, temperature & supply-voltage compensated; Accuracy +/- 0,5 dB)
Amplifier: Lab Gruppen FP10000Q, bridged if necessary; for KS28 and SB18 L'Acoustics LA12X
ARTA Measurement Box V3.2
Voltmeter w/ 1,5% accuracy

All acoustic measurements were done in ground plane (ref.: Groundplane Acoustic Measurement of Loudspeaker Systems - Gander, AES, 1980), in a true outdoor enviroment, with no relevant obstacles to the wavelengths in question.

Further commentary (because there is a lot of common misconception on outdoor measurements):

minor vegetation does not influence bass measurements
soil / lawn is perfectly acoustically hard at low frequencies (verified by my own comparative measurements vs. asphalt)
done on wind free days

All acoustic measurements were performed at 2 metres distance and scaled back to 1m (+6 dB).

Calibration is tested / verified before and after each measurement series.

All measurements are repeated at least once, and the result only accepted as valid / reproducable if results from two or more measurements match perfectly (within tenths of a dB).

For the sensitivity measurement, amplifier voltage (Vrms) was determined with a sine signal; 2 volts = 1 watt at 4 ohms, 2,83 volts = 1 watt at 8 ohms.

Double boxes were normalized to single boxes in the sensitivity measurement via subtracting 3 dB for half the membrane area (sd), and in the Max. SPL measurement subtracting another 3 dB (6 dB total) for half the amp power.

The Max. SPL @ THD (total harmonic distortion) measurement tests the mechanical performance of the speaker. THD increases with membrane excursion.
The tests plays sine tones, starting with -30 dB (= 1/1000th) of the maximum available amplification, increasing in 0,5 dB steps until the pre-set (in this case 10%) distortion limit is reached. It then proceeds to the next frequency in 1/12 steps and repeats the procedure.
Maximum amplification supplied to each box was its program power (usually RMS/AES x2); except the KS28 & SB18, which received the system amping (L'Acoustics LA12X).
Frequency range tested was ~30 - 60 Hz; above ~60 Hz almost all subwoofers are not limited mechanically anymore, but just how much thermal stress their voice coils can endure.

A demonstration of a complete run of the Max. SPL @ THD test can be found here:    • ARTA / STEPS distortion limited SPL measur...  


Austrian subwoofer test powered by Austrian music.
Track ID: Ling Ling - Tear Drops from the Sky


0:00 Intro
0:26 Test Field
0:53 Test Procedure
1:07 DIY Bassreflex w/ the box 15LB075
1:34 DIY Bassreflex w/ the box 18-500
2:01 DIY Bassreflex w/ 18Sound 18NTLW5000 160l / 32Hz
2:28 DIY Bassreflex w/ 18Sound 18NTLW5000 180l / 36Hz
2:55 DB Technologies S118R
3:22 Electrovoice Xsub
3:49 L'Acoustics KS28
4:16 L'Acoustics SB18
4:43 THAM 15 w/ the box 15LB100
5:10 TW Audio B30
5:37 X!Max BR118Ex w/ 18NTLW5000
6:04 Max. SPL @ 10% THD, all boxes
6:58 Outro