MTX Audio RTS15-04
Best box: 132.2 L bass reflex tuned to 21.8 Hz · F3 30.5 Hz
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Comparable 15.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the MTX Audio RTS15-04 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
- Large enclosure volume (132.2 L) requires extensive internal matrix bracing to prevent panel resonance.
Recommended Bass Reflex (Vented)
PORT BUILDABLE| Net Box Volume (Vb) | 132.2 Liters |
| Tuning Frequency (Fb) | 21.8 Hz |
| F3 (-3 dB Cutoff) | 30.5 Hz |
| F6 / F10 Extension | 24.8 Hz / 19.0 Hz |
| Port Inner Diameter | Ø 10.0 cm |
| Port Physical Length | 30.3 cm |
| First Pipe Resonance | 567.0 Hz |
| Estimated MOL @ F3 | 116.6 dB SPL |
Sealed (Acoustic Suspension) — compromise
SUITS INFINITE / OPEN BAFFLEWith Qts 0.621 a Butterworth (Qtc 0.707) box would be many times Vas. A box equal to Vas reaches Qtc 0.878; for a flat response this driver is better used on an infinite (IB) or open baffle.
| Net Box Volume (Vb) | 165.2 Liters |
| System Q (Qtc) | 0.878 (above Butterworth) |
| System Resonance (Fc) | 36.3 Hz |
| F3 (-3 dB Cutoff) | 31.7 Hz |
| F6 / F10 Extension | 25.5 Hz / 20.0 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 25.7 Hz |
| Total Q (Qts) | 0.621 |
| Electrical Q (Qes) | 0.704 |
| Mechanical Q (Qms) | 5.25 |
| Equivalent Volume (Vas) | 165.2 Liters |
| Diaphragm Area (Sd) | 840.0 cm² |
| DC Resistance (Re) | 3.79 Ω |
| Efficiency Bandwidth Product (EBP) | 36.5 |
| Linear Excursion (Xmax) | 11.7 mm |
| Thermal Power (Pe) | N/A W |
| Nominal Diameter | 15.0" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for MTX Audio RTS15-04?
Load Forge's calculated alignment puts MTX Audio RTS15-04 in a 132.2 liter vented enclosure tuned to 21.8 Hz, reaching an F3 cutoff of approximately 30.5 Hz.
Can MTX Audio RTS15-04 be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 165.2 liters with a Qtc of 0.878 (above Butterworth), the system exhibits an F3 of 31.7 Hz.
What port dimensions should be used for MTX Audio RTS15-04 to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 10.0 cm with a length of 30.3 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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