## 1 Introduction
The purpose of the system related to vision research, and therefore, the Color Rendering Index (CRI) was used to analyze the differences between spectra. [PERSON] et al. [12] integrated 31 different LEDs (from 400 to 700 nm) into a cube capable of producing D65, D50, A, and E illuminants and mitigating the SPD of fluorescent and high-pressure lamps. They used a large number of low-power LEDs, and therefore, the spectral shift could be neglected. Apart from colorimetric criteria (correlated color temperature CCT, color rendering indexes Ra and Rb, chromaticity coordinates CIE-xy), to evaluate the differences between intended and obtained spectra, they used the goodness-of-fit coefficient (GFC), mean absolute error (MAE), and root mean square error (RMSE). Colorimetric criteria are not fully reliable for evaluating the fit quality due to the metamerism effect [2]. [PERSON] et al. [9] developed an illuminance meter calibration system utilizing the LSTLSs to replace traditional incandescent lamps. Their source comprised 23 types of LEDs, including monochromatic and white high-power LEDs operating in the wavelength range from 340 nm to 800 nm. It reproduced the A illuminant A within illuminance levels from 800 lx to 10,000 lx, achieving a coincidence error (\(\Delta\)ES-A) below 7.5%. Recently, [PERSON] and [PERSON] [10] used the developed LSTLS to additionally simulate the illuminant D50 for imaging and graphics fields. The quality of the D50 simulator was evaluated by applying Ra and \(\Delta\)u'\({}_{10}\)v'\({}_{10}\) parameters. The LSTLS developed by [PERSON] and [PERSON] [21] has 10 chromatic LED channels spread across the visible spectrum. They investigated three different heuristic approaches: (i) a genetic algorithm, (ii) simulated annealing, and (iii) a Monte Carlo simulation. The error functions used were the mean absolute percentage deviation (MAPD), measured for each wavelength (to estimate the quality of spectral matching), and the color difference \(\Delta\)u'v' with assumed target spectra. None of these investigations included the effect of spectral components' selection. However, other researchers have noticed this aspect. [PERSON] et al. [26] developed an algorithm for determining the optimal radiant flux for each LED in the LSTLS to synthesize spectra by maximizing averaged LED utilization rates. They revealed that peak wavelength, full-width half maximum (FWHM), and radiant flux are crucial for optimal LED selection. Later, the optimal selection of LEDs for realizing CIE standard illuminants and blackbody radiation at different color temperatures was analyzed by [PERSON] et al. [28]. They proved that careful selection of peak wavelengths and FWHM values allows for minimizing the mean square error (MSE) of the synthesized SPDs. [PERSON] et al. [18] proposed a novel numerical method for evaluating the contributions of each LED channel in LSTLSs. Due to their intended application (the calibration of various optical sensors), their selection criterion was applied in the spectral range from 700 nm to 1070 nm. They noticed that the SPD of each LED could be initially approximated by a Gaussian curve to accelerate calculations. Still, they suggested that final calculations should be performed with real (measured) SPDs. Recently, researchers have investigated LSTLS by employing systematic prediction algorithms. [PERSON] et al. [29] utilized Gaussian and asymmetric Gaussian distribution functions to tune 32 LEDs, successfully simulating CIE A and D65 with less than a 5% deviation. [PERSON] et al. [30] used machine learning algorithms to forecast the SPD of full-spectrum white LEDs. Meanwhile, [PERSON] et al. [31] employed deep learning techniques to predict the SPD of LED systems undergoing multiple degradation mechanisms. [PERSON] et al. [32] applied differential evolution algorithms for multi-type LED-based AM1.5G solar spectrum synthesis. The spectral match was determined as the ratio of the actual percentage of irradiance that falls on the spectral range of concern to the required percentage of irradiance.