Lowther DX55
Best box: 3.0 L bass reflex tuned to 103.5 Hz · F3 127.4 Hz
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Comparable 5.5" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Lowther DX55 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
- The textbook alignment (1.5 L at 115.0 Hz) would need a 26.1 cm port; the recommendation is retuned to 3.0 L at 103.5 Hz so the port can be built.
- 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) | 3.0 Liters |
| Tuning Frequency (Fb) | 103.5 Hz |
| F3 (-3 dB Cutoff) | 127.4 Hz |
| F6 / F10 Extension | 100.3 Hz / 83.6 Hz |
| Port Inner Diameter ESTIMATED | Ø 5.0 cm |
| Port Physical Length | 14.7 cm |
| First Pipe Resonance | 1167.0 Hz |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 0.66 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 213.0 Hz |
| F3 (-3 dB Cutoff) | 245.3 Hz |
| F6 / F10 Extension | 202.9 Hz / 161.9 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 82.0 Hz |
| Total Q (Qts) | 0.262 |
| Electrical Q (Qes) | 0.274 |
| Mechanical Q (Qms) | 5.81 |
| Equivalent Volume (Vas) | 4.2 Liters |
| Diaphragm Area (Sd) | 105.5 cm² |
| DC Resistance (Re) | 7.4 Ω |
| Efficiency Bandwidth Product (EBP) | 298.9 |
| Linear Excursion (Xmax) | N/A mm |
| Thermal Power (Pe) | N/A W |
| Nominal Diameter | 5.5" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for Lowther DX55?
Load Forge's calculated alignment puts Lowther DX55 in a 3.0 liter vented enclosure tuned to 103.5 Hz, reaching an F3 cutoff of approximately 127.4 Hz.
Can Lowther DX55 be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 0.66 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 245.3 Hz.
What port dimensions should be used for Lowther DX55 to avoid port chuffing?
Xmax is not published for Lowther DX55, so the port is an empirical estimate: a 5.0 cm diameter with a length of 14.7 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
Embed this design card on DIYAudio, AVSForum, Reddit, or Facebook. It shows the calculated F3, MOL (when the power rating is published) and box parameters.
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