18SOUND 6NMB900
18SOUND (Eighteen Sound) 6NMB900 — 6" / 6 inch · Midrange without Bass (Mid) · Midrange · Neodymium
1.77" voice coil · 16 Ω
Part no.: 42A-CHS-MT-18S-0032
Documents
18SOUND 6NMB900 — 6" · Midrange Driver
200 W AES · 96 dB Sensitivity · Frequency range 200 Hz – 7000 Hz
Technical data
- Diameter: 6 "
- Voice coil: 1.73 "
- Power handling: 200 W AES
- Sensitivity: 96 dB
- Impedance: 16 Ω
- Magnet: Neo
- Weight: 1.25 kg
- Mounting depth: 73 mm
- Frequency range: 200 – 7000 Hz
Datasheet (PDF) · Manufacturer page
Series: NMB · Part no.: 42A-CHS-MT-18S-0032
18Sound 6NMB900: 6" neodymium midrange in 16 Ω for arrays and columns
The 6NMB900 from the NMB series by 18Sound (Eighteen Sound) is the 16 Ω version of a pure 6" midrange – meant for designs where several drivers hang in parallel on one amplifier channel without the total impedance dropping too far. Re 10.1 Ω, 200 W AES on a 1.73" voice coil and an operating range of 200 Hz to 7,000 Hz define the application: midrange in line arrays, columns and three-way cabinets.
The 96 dB sensitivity looks lower than that of 8 Ω drivers because at the same voltage only half the power arrives at 16 Ω – per watt the driver is no less efficient. The motor delivers BL 12.4 Tm on 9 g of moving mass, and the suspension is moderately damped with Fs 100 Hz, Qts 0.34 and Vas 6.65 l. Xmax is 3 mm, Le 0.19 mH, and the neodymium driver weighs 1.25 kg at a mounting depth of 73 mm.
Use and enclosure
The 6NMB900 works in a sealed midrange chamber, for which the guideline gives about 2.0 l with a system resonance of 208 Hz. Building the chamber larger lowers the resonance and gains distance to the lower crossover point, which should be well above 200 Hz. The vented calculation (guideline 4.5 l, tuned to 111 Hz, f3 around 118 Hz) has no practical use for a midrange without bass duties; the EBP of 263 shows anyway that the motor is meant for midrange or horn work. In a column with two drivers in parallel, the 16 Ω version yields an 8 Ω load again that any amplifier drives. The enclosure calculator on 42.audio helps size a shared or separate chamber.
The upper limit of 7,000 Hz allows crossovers to domes, ribbons or small compression drivers, sensibly well below that limit so the cone still radiates widely in the transition region.
What to look out for
- 16 Ω nominal, Re 10.1 Ω: two drivers in parallel give 8 Ω, ideal for multi-driver designs.
- 96 dB at 16 Ω: quieter than 8 Ω drivers at the same amplifier output voltage, level-match in the DSP.
- Xmax 3 mm: high-pass well above 200 Hz, no lower-mid duties.
- 1.25 kg and 73 mm mounting depth: light and shallow for arrays.
- Le 0.19 mH: flat impedance at the top, a passive crossover stays simple.
Frequently asked questions
Why does the 6NMB900 have only 96 dB when the 6NMB420 is rated at 100 dB?
The difference is impedance. The 6NMB900 is a 16 Ω driver with Re 10.1 Ω and receives only half the power at the same voltage. Referenced to power, both are comparably efficient; the 6NMB420 is also tuned very similarly with Fs 110 Hz, Qts 0.33 and Vas 6.1 l.
How do I wire several 6NMB900 drivers?
Two drivers in parallel give about 8 Ω – that is the classic reason for the 16 Ω version. In columns with more drivers, combine series and parallel wiring so the amplifier sees a load it can drive safely.
Which crossover frequencies is the driver meant for?
The operating range of 200 Hz to 7,000 Hz sets the limits. The high-pass sensibly sits well above 200 Hz and above the chamber's system resonance, the low-pass to the tweeter a good way below 7,000 Hz so the 6" cone still radiates evenly there.
At 42.audio you get the 18SOUND 6NMB900 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 | 16 Ω |
|---|---|
| Resonance frequency fs | 100 Hz |
| Total Q Qts | 0.34 |
| Electrical Q Qes | 0.38 |
| Mechanical Q Qms | 3.1 |
| Equivalent volume Vas | 6.7 l |
| Moving mass Mms | 9.0 g |
| Cone area Sd | 130 cm² |
| Linear excursion Xmax | 3 mm |
| Force factor BL | 12.4 Tm |
| DC resistance Re | 10.1 Ω |
| Voice coil inductance Le | 0.19 mH |
Comparable drivers
Same size, same type, Qts within ±30 %.
- 18 Sound 6NMB420fs 110 Hz · Qts 0.33 · Vas 6.1 l · in the database
- 18 Sound 6NTLW2000fs 86 Hz · Qts 0.35 · Vas 4.6 l · in the database
- 18 Sound 6M44fs 102 Hz · Qts 0.29 · Vas 3.8 l · in the database
- 18 Sound 6NTLW2000fs 86 Hz · Qts 0.38 · Vas 4.8 l · in the database
- SB Acoustics MR16TX-8fs 35 Hz · Qts 0.31 · in the database
- 18 Sound 6ND430fs 61 Hz · Qts 0.27 · Vas 12.6 l · in the database
Specifications
| Allgemein | |
|---|---|
| Manufacturer | 18SOUND |
| Category | Mid Frequency |
| Series | NMB |
| Magnet | Neo |
| Impedance (Ω) | 16 |
| Power handling (W) | 200 |
| Sensitivity (dB) | 96 |
| Frequency from (Hz) | 200 |
| Frequency to (Hz) | 7000 |
| Abmessungen & Korb | |
|---|---|
| Diameter | 6 |
| Voice coil (inch) | 1.73 |
| Mounting depth (mm) | 73 |
| Weight (kg) | 1.25 |
| Thiele-Small-Parameter | |
|---|---|
| Re (Ω) | 10.1 |
| Le (mH) | 0.19 |
| Fs (Hz) | 100 |
| Qms | 3.1 |
| Qes | 0.38 |
| Qts | 0.34 |
| Vas (l) | 6.65 |
| Xmax (mm) | 3 |
| BL (Tm) | 12.4 |
| Mms (kg) | 0.009 |
| Sd (m²) | 0.013 |