Aims: This study investigates how electrode array types— straight versus perimodiolar—affect cochlear implant (CI) placement and outcomes using cone beam computed tomography (CBCT) and evoked electrical auditory brainstem responses (eABR). Array designs influence electrode proximity to neural structures, impacting neural stimulation efficacy. Methods: We analyzed 108 patients using CBCT to compare straight and perimodiolar electrode arrays in terms of angular depth, spiral diameter, electrode to modiolus distance, wrapping factor and intracochlear positioning index (ICPI). A subset of 50 patients underwent eABR assessments across cochlear regions. Results: Significant differences were found between array types. Straight arrays showed less variability with consistent lateral placement compared to perimodiolar arrays. Measurements revealed differences for perimodiolar and straight arrays: wrapping factor (M = 0.692 vs. 0.826; t(11) = 8.104, p = 0.000), angular depth (M = 351.2° vs. 437°; t(11)=4.527, p = 0.000), spiral diameter (M = 3.24 mm vs. 5.027 mm; t(11) =11.1, p = 0.000), and modified ICPI (M = 0.628 vs. 0.783; t(11) =9.742, p = 0.000). Wave V eABR results showed larger average amplitudes with straight arrays in basal and mid regions (p < 0.05), suggesting potentially enhanced neural stimulation and a more focused stimulation with perimodiolar arrays. Direct measures of electrode position correlated more strongly with eV ABR amplitudes. In contrast, derived measures show no correlation with electrophysiology. Conclusion: Our findings indicate the importance of electrode array type in CI outcomes, emphasizing the need for precise positioning to optimize neural stimulation and clinical outcomes. Personalized array selection based on CBCT assessments may lead to improved speech perception, pitch discrimination, and overall auditory function. Future research should aim to refine stimulation strategies to maximize CI benefits.