A difference in the limiting settings?
91 It is not disputed that Dynamic represented that the testing of the two devices at their lowest limiting settings provided an appropriate comparative basis for testing for intelligibility of speech. The s 52 contravention pleaded is that the lowest limiting setting at which SoundShield was tested was significantly lower than that for M15D, and the test results consequently conveyed a misleading assessment of the comparative performance capabilities of the SoundShield device. This is particularised as follows:
(a) SoundShield has four settings, namely 80dB, 85dB, 90dB and 95dB. The lowest limiting setting is 80dB, and it was to the lowest limiting setting that the comparison report states that the device was set. However the longer form of the comparison report (dated 31 May 2005) states that during the test the device was set at "Limiter Setting 1", which is 95dB.
(b) M15D has an absolute acoustic ceiling, and therefore a lowest limiting setting, of 102dB.
92 Mr Guest's initial complaint seems to have been that the report wrongly said that SoundShield was set to 80dB, which was its "lowest limiting setting", whereas it was in fact set to 95dB, which was its "least limiting setting" (ie setting 1). On Professor Blamey's evidence, which I accept, there is no difference between "lowest limiting setting" and "least limiting setting". Both mean the setting that provides the least limiting, namely 95dB, being the setting chosen. In any event, Polaris' case was not conducted on the basis of Mr Guest's initial understanding of the position, but on the basis that SoundShield was tested on a limiting setting of 95dB whereas M15D was tested on a limiting setting of 102dB. Polaris' contention was that a louder sound was heard on the M15D, which would enhance intelligibility. This was the way Mr Guest put Polaris' complaint in his second affidavit: the M15D device used in the comparison test had an acoustic ceiling of at least 7dB more than SoundShield, and this difference "would have resulted in the device with the higher limit being easier to hear with ie have higher intelligibility".
93 As appears from [70], the voluntary G616 standard prescribes an upper limit of 102dBA SPL at DRP. It was common ground that SoundShield's lowest limiting setting was setting 1 or the 95dB setting. The M15D was a pre‑release prototype. The M15D ultimately released to the market was advertised as having a limit of 102dBA. Mr Gherbaz and Mr McNeill both said the M15D used in the comparison test had a lowest limiting setting of 102dBA.
94 Thus, says Polaris, the comparison was between SoundShield with limiting of 95dBA and the M15D with limiting of 102dBA. This comparison was said to be unfair because the M15D provided less limiting, and thus the listener received more sound than a listener to SoundShield, "with a resultant likely effect on intelligibility" - the SoundShield caused sound to be heard more quietly. Polaris relied on Professor Newell's evidence to establish these matters.
95 The respondents relied on Mr McNeill's test, which is described at [83]. They said this showed that both devices were limiting speech signals at the same level: around 95dBA SPL at DRP (94.7 for M15D and 96.3 for SoundShield) measured at 125ms RMS.
96 Polaris took issue with the relevance of Mr McNeill's test. It said that although he described the test as "a measurement of the acoustic limit for speech" of the two devices, it was not that, but a measurement of their outputs with a single 100mV input, which did not test the limiting of the devices. In cross‑examination Mr McNeill accepted that he had measured the devices' acoustic outputs at the ear drum. He was not trying to verify compliance with any specification. He was trying to reproduce the conditions of the Dynamic test to verify that it was fair in that both headsets were putting out "similar output levels, acoustic levels".
97 In my view Mr McNeill's test does not displace the prima facie 7dB gap between SoundShield's limiting of 95dBA and M15D's limiting of 102dBA. Putting the matter another way, the test does not establish that the M15D tested by Dynamic had the same limit as the SoundShield tested, namely 95dBA as opposed to its published limit of 102dBA, the limit Mr Gherbaz, and Mr McNeill in another connection (see [93]), said it had. As Mr McNeill conceded, it was not a test of the acoustic limits for speech, but of output levels.
98 As appears at [96], Mr McNeill was trying to reproduce the conditions of the Dynamic test to verify that it was fair in that both headsets were putting out similar output levels. Polaris drew attention to many respects in which Mr McNeill's test did not replicate Dynamic's. I mention only one of them. The Dynamic test was done with background noise. Mr McNeill's was not. This is an important difference for present purposes because, as Mr McNeill pointed out, it was a feature of the M15D (not shared by SoundShield) that when it detected an increase in ambient background noise, it attempted to increase the output volume level "so long as that does not exceed the limiting profile selected". In other words, the measured output for the M15D in the absence of background noise is likely to be lower than the output in otherwise the same conditions but with background noise. As Polaris points out, this would explain the difference in perceived loudness recorded by the subjects in the Dynamic test (Figure 2), with the M15D increasing its output in background noise. More importantly, for present purposes, because a higher output could be achieved in different test conditions (with background noise), Mr McNeill's test is not a test of any limit of the M15D.
99 The respondents also relied on Mr Dickson's August 2005 test described at [80], which showed much the same output levels for M15D and SoundShield - 91.7 and 91.4dB SPL at DRP respectively. Mr Dickson's test was of the same character as Mr McNeill's. It tested output levels and not acoustic limits for speech. He agreed that what his graph demonstrated was output measurements, and that they did not directly give any information about the acoustic limits of the devices. His test was done without background noise, and he agreed with Mr McNeill that the M15D had attributes that improved loudness in noise.
100 Confirmation that Mr Dickson tested for output levels and not limiting levels is contained in the note of a telephone call made by Professor Blamey in December 2005 to Dr Harvey Dillon of NAL in response to an enquiry as to the limiting level for the M15D tested in May 2005. The note is in part as follows:
HD indicated that he wanted to discuss the SoundShield/ADRO study, and that he had seen a copy of the document that [Dynamic] had supplied to Plantronics. HD asked what was the limiting level for the ADRO device tested. He inferred that the poorer performance of the SoundShield device may have been caused by using a lower limiting level than was used for the ADRO device.
PB replied that the limiting levels for the devices had not been measured or compared as part of the study. The output levels for the two devices had been measured and matched at the start of the study. SoundShield was set to the typical settings used in Australian call centres as stated in the document. The ADRO device was set to a similar output level.
101 It was on receipt of the enquiry from Dr Dillon that Professor Blamey asked Mr Dickson to provide him with the measurements of the output levels used in the May comparison test. Mr Dickson's graph was provided to Professor Blamey in response. Professor Blamey said it showed output levels or spectra for speech averaged over 10 seconds. It is clear therefore that the measurement referred to in the fifth sentence of the passage quoted at [100] is Mr Dickson's, and that it was not a measurement of limiting levels.
102 The respondents have not established, by resort to Mr McNeill's or Mr Dickson's tests, that in the Dynamic test both devices had more or less the same acoustic limits. SoundShield was tested on a setting of 95dBA and M15D on 102dBA. Professor Blamey agreed that his statement that the acoustic limit for speech for the M15D in the measurements performed at Plantronics was 95dB SPL at DRP was based on Mr McNeill's test and that he was not aware of any other test "for acoustic limit for speech" for the M15D that had been performed for this litigation. He also agreed that the only tests for the output levels for the devices were those of Mr McNeill and Mr Dickson.
103 Polaris claimed that Dynamic could have done a "fair" test by setting both devices to TT4 limiting settings or TT4+5dB. In this connection it relied on an email from Trillium (Mr Hecker) to Plantronics (Mr Gherbaz) of 20 April 2005 in which Mr Hecker expressed "concern" that Plantronics was "trying to benchmark against something that isn't TT4". Mr Hecker said he had tested SoundShield to TT4 and it appeared to be "behaving properly". Polaris also relied on an email from Mr Dickson to Mr McNeill of 29 April 2005 which disclosed that the former was "currently finalising two versions of Tecate/Xenica software". One was M15D version 1.10a to compete with SoundShield on non‑Telstra setting, and the other, version 1.10b, to compete with SoundShield "for full TT4 compliance test at Trillium". On this basis Polaris contended that Dynamic could have done a test comparing like with like, but chose not to. This, it said, left the reader of the report to infer that the lowest limiting setting was the same for each device, when it was not. That was what was misleading about the report.
104 In this same connection Polaris relies on Mr McNeill's evidence in cross‑examination. He was asked what he understood Mr Hecker meant in the 20 April 2005 email that Plantronics was "trying to benchmark against something that isn't TT4". He replied:
this comes back to the relaxation of the space that Polaris had negotiated with Telstra, and if we were benchmarking our product with a limiting profile of TT4 against SoundShield, with a limiting setting of TT4+5, then they wouldn't match. They wouldn't be a fair benchmark.
105 Dynamic propounded three reasons for rejecting Polaris' case. The first was that "both devices were set at the lowest limiting setting", which meant that the volume of the sound heard by the listener was least restricted by the devices. It is true that SoundShield was set to its lowest limiting setting of 95dB and that M15D was set to its lowest limiting setting of 102dB. However, Polaris' grievance is that the report misleadingly represented that the two devices were set to the same lowest limiting setting, when they were not. As appears above, I have concluded that they were set to different settings.
106 Dynamic's second reason for asserting that Polaris' claim must fail was that both devices were set to the lowest setting each was capable of giving for speech, namely 95dB, which on both is the point at which their speech limiting capacities commence to operate. As I have found, the devices were not set at the same 95dB setting.
107 Dynamic's third reason was that both devices were tested by measurement of their sound output level at 91.4dB SPL at DRP (M15D) and 91.7dB SPL at DRP (SoundShield) in the conditions used, the effect of which was that the sound used was below the sound limiting capacities in each device. This contention is based on Mr Dickson's measurements of December 2005 and his supporting graph. As appears from what I have said at [99], Mr Dickson, as he conceded, was measuring outputs and not the acoustic limits of the devices. Dynamic's third reason is itself predicated on a sound output level measurement.
108 Dynamic's other related submissions founder on the failure to distinguish between maximum sound outputs and acoustic limits. Polaris' complaint relates to the latter. The admitted representation is that the testing of the two devices at their lowest limiting settings provided an appropriate comparative basis for testing for intelligibility of speech. The representation is said to be misleading because the lowest limiting setting at which SoundShield was tested was significantly lower than that for M15D. This does not involve a comparison of maximum sound outputs, but of acoustic limits. Thus Dynamic's assertion that Mr Dickson's evidence that both devices produced the same level of sound to listeners rebutted Polaris' contention that the M15D was tested at a higher volume than SoundShield, does not meet Polaris' point. Similarly, Dynamic's concluding submission that Polaris has failed to establish that the devices were tested "at unequal volumes" also misses the point, based as it is on Mr McNeill's and Mr Dickson's tests of sound outputs.
109 Plantronics relied on a passage in Mr McNeill's second affidavit in which he said that from his role in leading the design team for the M15D, he was aware that "the limiting regime provided for by limiting mode 3 causes the 125ms RMS speech average for the M15D to be limited to 95dB SPL at the drum reference point". Mr McNeill provided no reasoning or explanation to support this bald assertion. He was not in this affidavit relying on his February 2008 test, which had since his earlier affidavit been subjected to criticism by Mr Fisher. In Cadbury Schweppes Pty Ltd v Darrell Lea Chocolate Shops Pty Ltd (2007) 159 FCR 397 at [108] the Full Court said:
unless a witness states in his or her evidence in chief the grounds and reasoning that have led to the opinion, the opinion is valueless. Before the Court can assess the value of an opinion, it must know the facts on which it is based. If the opinion is based on irrelevant facts or facts that are clearly not going to be proved, the opinion is likely to be valueless. It should not be for a cross-examiner to endeavour to elicit the facts or assumptions upon which an opinion is expressed, and it would be unfair to leave such matters to the cross‑examiner. Except in a straightforward, uncomplicated case, where the facts are admitted or otherwise readily identified, opinion evidence would normally be rejected under s 135 if the facts or assumptions upon which the opinion is based are not expressly stated.
It is for the Court to judge the reliability of, and the weight to be given to, particular evidence. Opinion evidence, like any other evidence, must be comprehensible and reach conclusions that are rationally based. The process of inference or reasoning that leads to conclusions ought to be stated or revealed in a way that enables the conclusions to be tested and a judgment to be made about their reliability and the weight that should be given to them.
110 Polaris urged me to attach no weight to Mr McNeill's statement of his "awareness". This is far from being a "straightforward, uncomplicated case", and the evidence in issue is of central importance to the lowest limiting setting issue. Mr McNeill's assertion amounts to no more than that he knows something because of his expertise. I attach no weight to the assertion.