This is a specialized and potent tuning for a 7-string Electric Bass, designed to deliver an incredibly deep and resonant sound. As the name suggests, it is derived from a standard 7-string bass tuning (typically B-E-A-D-G-C-F, tuned in perfect fourths), but with two significant modifications to the lowest strings to achieve an extended low range.

Verbal Analysis

The core of this tuning lies in its "Drop A" on the lowest string (String 7) and "Drop D" on the second lowest string (String 6). This configuration creates an extremely extended low range, perfect for heavy music genres such as metal, djent, and progressive rock, where guttural bass lines and a formidable rhythmic foundation are paramount. The combination of A1 and D2 provides an incredibly deep sonic foundation. The upper strings (A2-D3-G3-C4-F4) largely maintain a conventional perfect fourths interval structure, which is familiar to most bass players and facilitates easy scale and arpeggio playing.

Technical Analysis

• Target Notes: A1 - D2 - A2 - D3 - G3 - C4 - F4 (from lowest to highest string).
• Interval Structure:
  • String 7 (A1) to String 6 (D2): Perfect 4th
  • String 6 (D2) to String 5 (A2): Perfect 5th
  • String 5 (A2) to String 4 (D3): Perfect 4th
  • String 4 (D3) to String 3 (G3): Perfect 4th
  • String 3 (G3) to String 2 (C4): Perfect 4th
  • String 2 (C4) to String 1 (F4): Perfect 4th
• The most distinctive feature is the Perfect 5th interval between D2 (String 6) and A2 (String 5). This interval is crucial for directly facilitating open D5 power chords, making rapid, chugging riffs highly accessible on these strings.
• The lowest three strings, A1-D2-A2, create a powerful open A5 power chord (A1 is the root, A2 is the octave) with the D2 adding a strong resonant fourth. This configuration offers immense flexibility for low-end riffing.
• The remaining upper strings (A2-D3-G3-C4-F4) are tuned in perfect fourths, providing a consistent fretboard logic for melodic and harmonic playing, similar to a standard 5-string bass.

Open Chords and Accessibility

This tuning excels at providing immediate access to powerful low-end chords and riffs:

• A5 Power Chord: By playing the open A1 (string 7) and A2 (string 5), you get a massive open A power chord. The D2 (string 6) can be incorporated for an even thicker, more resonant sound, effectively creating an A-D-A drone.
• D5 Power Chord: The open D2 (string 6) and A2 (string 5) form a perfect D5 power chord, ideal for heavy, driving basslines.
• General Power Chords: Across any adjacent strings tuned in fourths (strings 5-1), standard power chord shapes (root-fifth or root-octave) are easily achievable. For instance, playing any note on string 5 and then the same fret on string 4 will yield a perfect fourth, which forms the basis for many bass riffs and voicings.
• Octaves: Octaves are readily available across the perfect fourths sections (A2-D3-G3-C4-F4) by fretting a note and then two frets higher on the string above, or by using common octave shapes across non-adjacent strings.

Tuning Notes

• String 7 (Lowest): A1
• String 6: D2
• String 5: A2
• String 4: D3
• String 3: G3
• String 2: C4
• String 1 (Highest): F4

How to Tune Your Bass

Follow these instructions carefully to achieve the 7-string Bass, Drop D, Drop A tuning. Pay close attention to the direction and number of semitones for each string.

• String 7 (Lowest): To reach A1, tune this string down 2 semitones.
• String 6: To reach D2, tune this string down 2 semitones.
• String 5: To reach A2, keep this string as is; no change (0 semitones).
• String 4: To reach D3, keep this string as is; no change (0 semitones).
• String 3: To reach G3, keep this string as is; no change (0 semitones).
• String 2: To reach C4, tune this string up 1 semitones.
• String 1 (Highest): To reach F4, tune this string up 1 semitones.

Important Note on String Gauge: Generally, if a string needs to be tuned down by more than 4 semitones (e.g., -5 or more) or tuned up by more than 4 semitones (e.g., +5 or more), it's advisable to consider a different string gauge. This helps maintain proper string tension, intonation, and prevents potential damage to your instrument or strings. For this specific tuning, the movements are relatively small (within +/- 2 semitones), suggesting that a standard string gauge for a 7-string bass should be suitable. However, always exercise caution and listen for excessive tension or looseness, especially if your bass was previously set up for a very different tuning.