There can be several reasons why you might hear bass from your neighbor's car but not from your own car, even if both vehicles have equally good sound systems. Here are a few possible explanations:
Soundproofing: Your neighbor's car might have better soundproofing than yours. Cars with superior soundproofing materials and techniques can effectively block external noise from entering the cabin, including low-frequency bass sounds. On the other hand, if your car has less effective soundproofing, the bass frequencies may leak in from the outside, making it difficult to hear them clearly.
Speaker placement and positioning: The positioning of speakers within a car can affect the way sound is projected and perceived. Even if both cars have equally good sound systems, the specific placement of speakers in your neighbor's car might be more optimal for producing and transmitting bass frequencies. This can result in a more noticeable bass experience from their vehicle compared to yours.
Acoustic environment: The surrounding environment can play a significant role in how sound travels and is perceived. If your neighbor's car is parked in an area that amplifies or reflects bass frequencies, such as near a building or in a narrow street, the bass sound waves can bounce off surfaces and reach your ears more prominently. Meanwhile, if your car is parked in a different location with different acoustic properties, the bass might not be as perceptible.
Equalizer settings: The equalizer settings on your car's audio system can affect the overall sound output. If your equalizer settings are not adjusted to emphasize or boost the bass frequencies, it may make the bass less noticeable in your car. On the other hand, your neighbor might have adjusted their equalizer settings to highlight the bass, resulting in a more prominent low-frequency sound.
Personal perception: Lastly, individual differences in hearing and personal preferences can also contribute to the perception of bass. People have different sensitivities to various frequencies, and what might be clearly audible to one person might not be as noticeable to another. So, even if the sound systems are similar, you might simply be more attuned to other frequency ranges or not as sensitive to low-frequency sounds.
Remember that these factors can vary from car to car and person to person, so it's essential to consider the specific circumstances in each case.