REDCATT 35FR
Best box: 1.5 L bass reflex tuned to 92.9 Hz · F3 87.7 Hz
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Comparable 3.5" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the REDCATT 35FR 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 74.3 Hz) would need a 67.5 cm port; the recommendation is retuned to 1.5 L at 92.9 Hz so the port can be built.
- Limited linear excursion (Xmax: 0.55 mm); set a high-pass subsonic filter at 25–30 Hz when driven with high power.
Recommended Bass Reflex (Vented)
PORT BUILDABLE| Net Box Volume (Vb) | 1.5 Liters |
| Tuning Frequency (Fb) | 92.9 Hz |
| F3 (-3 dB Cutoff) | 87.7 Hz |
| F6 / F10 Extension | 80.7 Hz / 72.7 Hz |
| Port Inner Diameter | Ø 5.0 cm |
| Port Physical Length | 41.9 cm |
| First Pipe Resonance | 411.0 Hz |
| Estimated MOL @ F3 | 90.2 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 0.48 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 138.2 Hz |
| F3 (-3 dB Cutoff) | 135.3 Hz |
| F6 / F10 Extension | 102.9 Hz / 77.8 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 67.0 Hz |
| Total Q (Qts) | 0.34 |
| Electrical Q (Qes) | 0.369 |
| Mechanical Q (Qms) | 4.35 |
| Equivalent Volume (Vas) | 1.6 Liters |
| Diaphragm Area (Sd) | 38.5 cm² |
| DC Resistance (Re) | 3.5 Ω |
| Efficiency Bandwidth Product (EBP) | 181.7 |
| Linear Excursion (Xmax) | 0.6 mm |
| Thermal Power (Pe) | 50.0 W |
| Nominal Diameter | 3.5" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for REDCATT 35FR?
Load Forge's calculated alignment puts REDCATT 35FR in a 1.5 liter vented enclosure tuned to 92.9 Hz, reaching an F3 cutoff of approximately 87.7 Hz.
Can REDCATT 35FR be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 0.48 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 135.3 Hz.
What port dimensions should be used for REDCATT 35FR to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 5.0 cm with a length of 41.9 cm is suggested; check the port air velocity at your drive level in the 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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