# Effect of Transducer Burn-In on Subjective and Objective Parameters of Loudspeakers
## 6 Conclusions  
Objective tests revealed the presence of slight differences in the impedance module characteristics of the analyzed loudspeaker sets. These differences result from increased compliance of the suspensions used in the transducers. Measurements of frequency responses and impedance modules of the tested sets showed discrepancies caused by technological processes on the assembly lines--both in the transducers themselves and in the complete loudspeaker systems.  
Changes in transducer parameters due to usage should not deviate more than 10% to 15% from their initial values. These differences are measured by performing a series of tests  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline
**Variable** & **SS Effect** & **df Effect** & **MS Effect** & **SS Error** & **df Error** & **MS Error** & **F** & **_p_ \\ \hline Clarity & 0.721 & 2 & 0.361 & 44.142 & 129 & 0.342 & 1.054 & 0.351 \\ Dynamics & 0.529 & 2 & 0.264 & 37.051 & 129 & 0.287 & 0.920 & 0.401 \\ Brightness & 0.601 & 2 & 0.301 & 36.119 & 129 & 0.280 & 1.073 & 0.345 \\ Overall rating & 0.642 & 2 & 0.321 & 45.903 & 129 & 0.356 & 0.902 & 0.408 \\ \hline \end{tabular}
\end{table}
Table 6: [PERSON]’s test for homogeneity of variance for burned-in and used devices.  
Figure 14: Mean ratings with 75% confidence intervals for used and burned-in audio devices.  
on a new transducer, followed by a 24 h operation using a program-type signal adjusted to the transducer's frequency range and at a voltage corresponding to its nominal power. After this period, the transducer is subjected to the same tests again, and the changes between the two-measurement series are analyzed. If the changes exceed the limits defined by standards (\(\pm\) 10-15%), the entire production batch is considered defective.  
Subjective tests did not reveal any significant differences between the tested pairs of loudspeaker sets. This aligns with the objective findings, which showed greater variation between units within the same production batch than between new, used, and conditioned (burned-in) sets. The expert panel consistently reported no noticeable changes in clarity, dynamics, brightness, or overall evaluation--regardless of musical genre or test sequence.  
The lack of perceived differences due to burning in is further supported by the fact that changes were reported in identical test sequences (A-A and B-B), while no differences were observed in cross-sequences (A-B and B-A). This suggests that the observed variations may stem from a subconscious desire to detect differences or from the emotional state of the expert group.  
In conclusion, burning in of loudspeaker sets results in minor changes to transducer parameters--as confirmed by objective tests (e.g., changes in suspension compliance)--but these do not significantly affect measurable acoustic parameters. In fact, greater discrepancies were observed among devices from the same production series than between new, used, and conditioned sets.  
Conceptualization, T.K. and B.K.; methodology, T.K., B.K. and J.K.; software, T.K.; validation, T.K., B.K. and J.K.; formal analysis, T.K. and J.K.; investigation, T.K., B.K. and J.K.; resources, B.K.; data curation, T.K.; writing--original draft preparation, T.K.; writing--review and editing, T.K. and B.K.; visualization, T.K.; supervision, T.K.; project administration, T.K.; funding acquisition, B.K. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. Informed Consent Statement: Informed consent was obtained from all subjects involved in the study. Data Availability Statement: The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author. The authors declare no conflicts of interest.