1991 Nissan D21 Speaker Sizes

The 1991 Nissan D21 factory audio system includes front door panel and behind seat locations that each accommodate a 6.5 inch speaker size. Midbass and full-range units serve as compatible speaker types for a sound system replacement or upgrade.

Specific details regarding locations, speaker sizes, and types are outlined in the compatibility chart.

Speaker Details by Location
Location Size Type Notes
Behind Seat 6.5 Midbass / Full-Range
  • May require seat removal
  • Limited working space
  • Medium replacement priority
  • Replacement difficulty: medium
Front Door Panel 6.5 Midbass / Full-Range
  • Standard installation
  • High replacement priority
  • Replacement difficulty: low

1991 Nissan D21 Speaker Replacement Summary

2 total positions
1 easy to replace
1 high priority
0 professional only

Replacement difficulty:

Low: 1 Medium: 1 High: 0

Replacement priority:

High: 1 Medium: 1 Low: 0

1991 Nissan D21 Radio Slot Size (DIN)

DIN Type Size (inch) Size (mm) Notes
Single DIN 7"×2" 180×50 Standard size for basic car radios with small display or no display
  • Always measure the slot before purchasing a new radio
  • Check slot depth - it may vary

Additional Notes

  • The 1991 Nissan D21 uses 6.5 inch speakers in both the behind seat and front door panel locations, which may simplify replacement planning since only one speaker size is needed for both positions.
  • Both speaker locations accept either midbass or full-range types, suggesting flexibility in choosing speakers optimized for mid-low frequencies only or units that handle the entire frequency spectrum.
  • Full-range speakers might offer broader sound coverage without requiring separate tweeters, while midbass units could pair with additional high-frequency drivers for potentially enhanced audio separation.
  • The front door panel position typically provides better stereo imaging and soundstage compared to behind seat mounting, which may influence prioritization during upgrades.
  • Behind seat speakers in this configuration might supplement door-mounted units or serve as the primary rear fill, depending on the existing factory setup and listening preferences.
  • The single DIN radio specification indicates a standard head unit mounting space, which allows for various aftermarket receiver options that could better drive upgraded speakers.