(BNS range oscillating between 44 and 41 Mpc .... not the optimal condition for injections)
We inject a set of low frequency acoustic lines in CEB hall using the two subwoofers setup. Injected frequencies 115, 95, 85, 73, 65, 54, 45, 40, 32, 27, 23, 19, 14, 43, 58.6Hz
(noticeably the subwoofer manages to inject quite loud lines down to 14Hz!)
We are able to inject acoustic lines at least a factor 10 above hall background noise. Not negligible noise leaks in DET LAB: microphone on SQZ bench measures a line that is a factor 5 to just 2 less than as measured in the hall.
We do not see effects in DARM or Hrec. Figura 1 = spectrogram of injected lines. An upper limit projection will follow.
We then tried some COLORED noise, in the band from 10Hz to 100Hz or so. In this case we do see some effect in DARM between 40 and 80Hz. Roughly we see a factor 3 increase of noise in DARM when HALL noise is more than a factor 20 above background and SQZ bench microphone noise is a factor 10 above background. See Figure 2. and 3. An upper limit projection will follow,
We tried to reproduce the noise increase injecting a line at 58.6Hz with an amplitude that is about a factor 100 larger than bkg in the hall mic, some effect is seen in DARM, but much smaller than with the broadband injection: Figura 4.
Conclusions: Acoustic noise increase of a factor up to 10 in the hall seems not to affect DARM significantly. DARM is sensitive to broadband acoustic noise in the 40 to 80Hz range exceeding a factor 20 in the hall. This noise could be passing through DETection LAB. This suspect is linked to the noise reduction effect that we measured last friday when switching off DET lab air conditioner (45588).
Here below the detailed log file with injection times:
quietREF: 1240303187 26 Apr 2019 08:39:29 UTC (26 Apr 2019 10:39:29 CEST)
%------ start injecting LINES (fft 4s) ---------
115Hz, 1e-4: 1240303689 26 Apr 2019 08:47:51 UTC (26 Apr 2019 10:47:51 CEST)
115Hz, 1e-3: 1240303781 26 Apr 2019 08:49:23 UTC (26 Apr 2019 10:49:23 CEST): ok si vede nei microfoni HALL e SQZ (10 volte meno)
95Hz, 5e-3: 1240304222 26 Apr 2019 08:56:44 UTC (26 Apr 2019 10:56:44 CEST): ok, almeno 10 volte sopra fondo, niente in hrec (8e-3 hall, 1e-3 sqz)
95Hz, 5e-3: 1240304468 26 Apr 2019 09:00:50 UTC (26 Apr 2019 11:00:50 CEST): (3e-3 hall, 1e-3 sqz, niente hrec)
85Hz, 8e-3: 1240304658 26 Apr 2019 09:04:00 UTC (26 Apr 2019 11:04:00 CEST): (5e-3 hall, 1.5 e-3 sqz, niente darm)
73Hz, 1e-2: 1240304814 26 Apr 2019 09:06:36 UTC (26 Apr 2019 11:06:36 CEST): (5e-3 hall, 2e-3 sqz, niente darm)
73Hz, 1.5e-2: 1240305007 26 Apr 2019 09:09:49 UTC (26 Apr 2019 11:09:49 CEST): (8e-3 hall, 4e-3 sqz, niente darm)
64Hz, 2.5e-2: 1240305301 26 Apr 2019 09:14:43 UTC (26 Apr 2019 11:14:43 CEST): (1.5e-3 hall, 2e-3 sqz, niente darm)
65Hz, 2.5e-2: 1240305371 26 Apr 2019 09:15:53 UTC (26 Apr 2019 11:15:53 CEST): (1.5e-3 hall, 1.5e-3 sqz, niente darm)
54Hz, 2.5E-2: 1240305525 26 Apr 2019 09:18:27 UTC (26 Apr 2019 11:18:27 CEST): 5e-2 hall, 5e-3 sqz, nothing DARM
45Hz, 2.5e-2: 1240305718 26 Apr 2019 09:21:40 UTC (26 Apr 2019 11:21:40 CEST): 1.5e-2 hall, 2e-3 SQZ, bozzetto in DARM?
off: 1240305915 26 Apr 2019 09:24:57 UTC (26 Apr 2019 11:24:57 CEST): ok sembra sparito... in DARM
45Hz, 2.5E-2: 1240306018 26 Apr 2019 09:26:40 UTC (26 Apr 2019 11:26:40 CEST): non si vede nulla in DARM
45Hz, 5e-2: 1240306152 26 Apr 2019 09:28:54 UTC (26 Apr 2019 11:28:54 CEST): nothing DARM
40Hz, 3E-2: 1240306268 26 Apr 2019 09:30:50 UTC (26 Apr 2019 11:30:50 CEST)
40Hz, 5e-2: 1240306367 26 Apr 2019 09:32:29 UTC (26 Apr 2019 11:32:29 CEST): 1e-2 hall, 8e-2 sqz, niente darm
32Hz, 5e-2: 1240306502 26 Apr 2019 09:34:44 UTC (26 Apr 2019 11:34:44 CEST): 1.5e-2 hall, 3e-3 sqz, no darm
27Hz, 5e-2: 1240306800 26 Apr 2019 09:39:42 UTC (26 Apr 2019 11:39:42 CEST): 1e-2 hall, 3e-3 sQZ, no darm
23Hz, 5e-2: 1240306970 26 Apr 2019 09:42:32 UTC (26 Apr 2019 11:42:32 CEST): 2e-3 hall, 8e-3 SQZ
23Hz, 0.1: 1240307160 26 Apr 2019 09:45:42 UTC (26 Apr 2019 11:45:42 CEST): 5e-3 hall, 1.2e-2 SQZ (penso si sta trasmettendo via strutturale in DET LAB) no DARM
19Hz, 0.15: 1240307321 26 Apr 2019 09:48:23 UTC (26 Apr 2019 11:48:23 CEST): 1.5e-2 hall, 1e-2 SQZ
19Hz, 0.2: 1240307447 26 Apr 2019 09:50:29 UTC (26 Apr 2019 11:50:29 CEST): 2e-2 hall, 1.2e-2 SQZ, no DARM
15Hz, 0.2: 1240307602 26 Apr 2019 09:53:04 UTC (26 Apr 2019 11:53:04 CEST): 3e-2 hall, quasi invisible in SQZ (paragonabile a rumore fondo, circa 2e-2), leggero peggioramento DARM?
OFF: 1240307602 26 Apr 2019 09:53:04 UTC (26 Apr 2019 11:53:04 CEST), ripeto (in DARM 15Hz si sovrappone a linee calib)
14Hz, 0.3: 1240307902 26 Apr 2019 09:58:04 UTC (26 Apr 2019 11:58:04 CEST): 3e-2 hall, invisible in SQZ paragonabile a rumore fondo, circa 3e-2, leggero effetto in DARM?
OFF: 1240308075 26 Apr 2019 10:00:57 UTC (26 Apr 2019 12:00:57 CEST), nessun effetto in DARM, sembra normale fluttuazione.
45Hz, 0.03: 1240308300 26 Apr 2019 10:04:42 UTC (26 Apr 2019 12:04:42 CEST): 2e-2 hall, 3e-3 sqz, no darm
43Hz, 0.03: 1240308455 26 Apr 2019 10:07:17 UTC (26 Apr 2019 12:07:17 CEST): 2e-2 hall, 3e-3 sqz, no darm
OFF: 1240308842 26 Apr 2019 10:13:44 UTC (26 Apr 2019 12:13:44 CEST)
%---------- COLORED noise
white 5e-4, 60, 100: 1240309116 26 Apr 2019 10:18:18 UTC (26 Apr 2019 12:18:18 CEST)
white 5e-3, 50, 80: 1240309321 26 Apr 2019 10:21:43 UTC (26 Apr 2019 12:21:43 CEST)
white 1e-2, 40, 60: 1240309436 26 Apr 2019 10:23:38 UTC (26 Apr 2019 12:23:38 CEST): sembra piccolo impatto in darm: tra 40 e 70Hz
white 3e-2, 30, 40: 1240309633 26 Apr 2019 10:26:55 UTC (26 Apr 2019 12:26:55 CEST): effetto well visible in DARM, struttura piu' eccitata: 58Hz, 45Hz
OFF: 1240309849 26 Apr 2019 10:30:31 UTC (26 Apr 2019 12:30:31 CEST)
58.6Hz, 0.03: 1240309982 26 Apr 2019 10:32:44 UTC (26 Apr 2019 12:32:44 CEST): quasi 0.1 hall, 3e-3 sqz, piccolo effetto in DARm
58.4 0.03: 1240310126 26 Apr 2019 10:35:08 UTC (26 Apr 2019 12:35:08 CEST): niente in DARM
OFF: 1240310212 26 Apr 2019 10:36:34 UTC (26 Apr 2019 12:36:34 CEST)