GRS 6AS-4
Best box: 6.7 L bass reflex tuned to 71.4 Hz · F3 111.5 Hz
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Comparable 6.5" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the GRS 6AS-4 does not fit your target box volume or tuning. Each entry links to its full enclosure design and Thiele/Small parameters.
⚠️ Engineering Notice for Builders
- Xmax is not published, so the port size is an empirical estimate (area ≥ 12 in² per ft³ of net volume, minimum by driver size), not a displacement calculation. Check air velocity in Load Forge Studio.
Recommended Bass Reflex (Vented)
PORT BUILDABLE| Net Box Volume (Vb) | 6.7 Liters |
| Tuning Frequency (Fb) | 71.4 Hz |
| F3 (-3 dB Cutoff) | 111.5 Hz |
| F6 / F10 Extension | 98.7 Hz / 82.1 Hz |
| Port Inner Diameter ESTIMATED | Ø 5.0 cm |
| Port Physical Length | 13.7 cm |
| First Pipe Resonance | 1260.0 Hz |
| Estimated MOL @ F3 | 106.6 dB SPL |
Sealed (Acoustic Suspension) — compromise
SUITS INFINITE / OPEN BAFFLEWith Qts 1.39 a Butterworth (Qtc 0.707) box would be many times Vas. A box equal to Vas reaches Qtc 1.966; for a flat response this driver is better used on an infinite (IB) or open baffle.
| Net Box Volume (Vb) | 8.4 Liters |
| System Q (Qtc) | 1.966 (above Butterworth: Qtc cannot fall below Qts (1.39)) |
| System Resonance (Fc) | 118.8 Hz |
| F3 (-3 dB Cutoff) | 96.7 Hz |
| F6 / F10 Extension | 85.2 Hz / 72.3 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 84.0 Hz |
| Total Q (Qts) | 1.39 |
| Electrical Q (Qes) | 1.928 |
| Mechanical Q (Qms) | 4.98 |
| Equivalent Volume (Vas) | 8.4 Liters |
| Diaphragm Area (Sd) | 120.1 cm² |
| DC Resistance (Re) | 3.5 Ω |
| Efficiency Bandwidth Product (EBP) | 43.6 |
| Linear Excursion (Xmax) | N/A mm |
| Thermal Power (Pe) | 40.0 W |
| Nominal Diameter | 6.5" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for GRS 6AS-4?
Load Forge's calculated alignment puts GRS 6AS-4 in a 6.7 liter vented enclosure tuned to 71.4 Hz, reaching an F3 cutoff of approximately 111.5 Hz.
Can GRS 6AS-4 be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 8.4 liters with a Qtc of 1.966 (above Butterworth: Qtc cannot fall below Qts (1.39)), the system exhibits an F3 of 96.7 Hz.
What port dimensions should be used for GRS 6AS-4 to avoid port chuffing?
Xmax is not published for GRS 6AS-4, so the port is an empirical estimate: a 5.0 cm diameter with a length of 13.7 cm (area at least 12 in² per ft³ of net volume). Check the air velocity at your power level in Load Forge Studio.
Shareable Acoustic Card for Forums & Social Media
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