18SOUND 15ND730
18SOUND (Eighteen Sound) 15ND730 — 15" / 15 inch · Woofer/Midrange (WM) · Subwoofer / Bass · Neodymium
3" voice coil · 8 Ω
Part no.: 42A-CHS-TT-18S-0055
Documents
18SOUND 15ND730 — 15" · Woofer
400 W AES · 99 dB Sensitivity · Frequency range 44 Hz – 4000 Hz
Technical data
- Diameter: 15 "
- Voice coil: 3 "
- Power handling: 400 W AES
- Sensitivity: 99 dB
- Impedance: 8 Ω
- Magnet: Neo
- Weight: 3.9 kg
- Mounting depth: 169 mm
- Frequency range: 44 – 4000 Hz
Datasheet (PDF) · Manufacturer page
Series: ND · Part no.: 42A-CHS-TT-18S-0055
18Sound 15ND730: 3.9 kg lightweight 15" neodymium woofer with 99 dB for 2-way tops
3.9 kg for a complete 15" driver: the 18Sound 15ND730 shows what a neodymium magnet does for weight. As a woofer/midrange driver in the ND series it is built for lightweight 2-way tops and portable systems where every kilo counts. The 3" voice coil handles 400 W AES, sensitivity is 99 dB and the usable range runs from 44 to 4,000 Hz.
The motor is generously sized at 21 Tm of force factor for 86 g of moving mass, which yields a Qts of 0.29 and a high Qms of 8.1. Fs is 44 Hz, Vas 156 l and Xmax 6.5 mm. With an EBP of 147 the 15ND730 is a clear vented-box candidate: it wants a compact, tightly tuned enclosure and delivers its level there through efficiency rather than excursion.
Use and enclosure
For vented use the guideline is about 67 l tuned to 56 Hz with a lower cut-off around 65 Hz. That is a typical format for a 15"/1.4" top that works alongside subwoofers and does not need to reach the low bass itself. Sealed, the figure is roughly 32 l with a system resonance near 107 Hz, which is interesting as a midrange chamber in a 3-way system if the lower crossover is set correspondingly high. Do the detailed design with the enclosure calculator at 42.audio.
The 1.35 mH inductance and the range up to 4,000 Hz permit a crossover to the compression driver that sits well below the upper limit yet still leaves a 1.4" driver enough headroom. The 169 mm mounting depth is not especially shallow for a neodymium driver; in return, the magnet no longer dominates the weight, which makes cabinets for flying frames or stands far easier to handle.
What to look out for
- 3.9 kg: neodymium magnet, ideal for flown tops or cabinets on stands.
- 99 dB sensitivity at 400 W AES: high level with moderate amplifier power.
- Xmax 6.5 mm: more than the MB models, but a subwoofer below still makes sense.
- Re 5.5 Ω, 8 Ω nominal: check the amplifier's 4 Ω stability for parallel wiring.
- 169 mm mounting depth, Le 1.35 mH, range up to 4,000 Hz.
Frequently asked questions
How does the 15ND730 differ from the Beyma 15P1000Fe/V2?
Both sit at a Qts around 0.3 and an Fs of 44 to 45 Hz, but the Beyma has a much smaller Vas of 80.7 l compared with 156 l for the 15ND730, and it is a ferrite driver. The 15ND730 scores with its 3.9 kg weight, the Beyma with more compact enclosures.
Is the 15ND730 enough as the only bass driver in a 2-way top?
For speech, acoustic music and smaller events, yes; the lower limit in the guideline box is around 65 Hz. For music with deep bass a subwoofer belongs underneath, if only because of the 6.5 mm Xmax.
Which amplifier suits the 15ND730?
An amplifier in the region of the 400 W AES rating at 8 Ω is sufficient; the 99 dB sensitivity means even smaller amplifiers deliver solid level. A high-pass filter below the tuning frequency protects the driver better than any surplus of watts.
18Sound 15ND730: manufacturer, spellings and classification
18Sound, 18 Sound and Eighteensound all refer to the same manufacturer: Eighteen Sound S.r.l. of Reggio Emilia, Italy. The 15ND730 is a 15-inch woofer with neodymium magnet from the ND series, available from 42.audio, 18Sound dealer in Germany, with datasheet and full specifications in the driver database.
At 42.audio you get the 18SOUND 15ND730 with datasheet PDF, all key data in the driver database and the enclosure calculator. More drivers from this manufacturer: Atlas 18Sound.
Thiele-Small parameters
| Nominal impedance | 8 Ω |
|---|---|
| Resonance frequency fs | 44 Hz |
| Total Q Qts | 0.29 |
| Electrical Q Qes | 0.3 |
| Mechanical Q Qms | 8.1 |
| Equivalent volume Vas | 156.0 l |
| Moving mass Mms | 86.0 g |
| Cone area Sd | 900 cm² |
| Linear excursion Xmax | 6.5 mm |
| Force factor BL | 21 Tm |
| DC resistance Re | 5.5 Ω |
| Voice coil inductance Le | 1.35 mH |
Enclosure suggestion
The EBP of 147 suggests a bass-reflex enclosure. EBP = fs / Qes = 44 / 0.3
Sealed (Qtc 0.707)
- Enclosure volume Vb
- 31.6 l
- System resonance Fc
- 107 Hz
- Cut-off frequency F3
- 107 Hz
Bass reflex (QB3 after Small)recommended
- Enclosure volume Vb
- 52.5 l
- Tuning frequency Fb
- 62 Hz
- Cut-off frequency F3
- 71 Hz
Vb is the required net internal volume, Fb the tuning frequency of the reflex port and F3 the frequency at which the level has dropped by 3 dB. Calculated approximation after Small. A starting point for simulation, not a finished build plan.
Comparable drivers
Same size, same type, Qts within ±30 %.
- B&C Speakers 15PZB100fs 39 Hz · Qts 0.29 · Vas 110 l · in the database
- Beyma 15P1000Fe/V2fs 45 Hz · Qts 0.3 · Vas 80.7 l · in the shop
- 18 Sound 15NTLW2500fs 45 Hz · Qts 0.3 · Vas 143 l · in the shop
- Ciare PW390fs 37 Hz · Qts 0.29 · Vas 225 l · in the database
- B&C Speakers 15NBX100fs 36 Hz · Qts 0.29 · Vas 125 l · in the database
- B&C Speakers 15NDL88fs 41 Hz · Qts 0.28 · Vas 154 l · in the database
Specifications
| Allgemein | |
|---|---|
| Manufacturer | 18SOUND |
| Category | Low Frequency |
| Series | ND |
| Magnet | Neo |
| Impedance (Ω) | 8 |
| Power handling (W) | 400 |
| Sensitivity (dB) | 99 |
| Frequency from (Hz) | 44 |
| Frequency to (Hz) | 4000 |
| Abmessungen & Korb | |
|---|---|
| Diameter | 15 |
| Voice coil (inch) | 3 |
| Mounting depth (mm) | 169 |
| Weight (kg) | 3.9 |
| Thiele-Small-Parameter | |
|---|---|
| Re (Ω) | 5.5 |
| Le (mH) | 1.35 |
| Fs (Hz) | 44 |
| Qms | 8.1 |
| Qes | 0.3 |
| Qts | 0.29 |
| Vas (l) | 156 |
| Xmax (mm) | 6.5 |
| BL (Tm) | 21 |
| Mms (kg) | 0.086 |
| Sd (m²) | 0.09 |