18SOUND 6M44
18SOUND (Eighteen Sound) 6M44 — 6" / 6 inch · Midrange without Bass (Mid) · Midrange · Ferrite
1.75" voice coil · 8 Ω
Part no.: 42A-CHS-MT-18S-0009
Documents
18SOUND 6M44 — 6" · Midrange Driver
200 W AES · 95 dB Sensitivity · Frequency range 140 Hz – 7000 Hz
Technical data
- Diameter: 6 "
- Voice coil: 1.75 "
- Power handling: 200 W AES
- Sensitivity: 95 dB
- Impedance: 8 Ω
- Magnet: Ferrite
- Weight: 3.4 kg
- Mounting depth: 85 mm
- Frequency range: 140 – 7000 Hz
Datasheet (PDF) · Manufacturer page
Series: M · Part no.: 42A-CHS-MT-18S-0009
18Sound 6M44: 6" ferrite midrange for sealed midrange chambers in three-way cabinets
The 6M44 belongs to the M series by 18Sound (Eighteen Sound) and is a pure midrange with no bass ambitions: an operating range of 140 Hz to 7,000 Hz, 95 dB sensitivity, 200 W AES on a 1.75" voice coil. The ferrite magnet brings the driver to 3.4 kg – considerable for a 6" and a hint that the motor is generously sized.
The parameters back that up: BL 13.4 Tm on only 16 g of moving mass, Fs 102 Hz, Qts 0.29 and a Vas of 3.8 l. The cone is light and tightly controlled, Xmax at 2.25 mm is small – just right for a driver that reproduces the vocal range between woofer and tweeter and gets by with little excursion. Le of 0.32 mH keeps the impedance flat up into the upper operating range, which simplifies crossover design.
Use and enclosure
The 6M44 belongs in a sealed midrange chamber. The guideline for it is tiny: about 0.8 l with a system resonance of 249 Hz. In practice the chamber may be larger so the system resonance drops and the high-pass gains more distance from the lower crossover point. The bass reflex guideline of 1.6 l tuned to 131 Hz with f3 around 150 Hz is possible on paper but offers no benefit for a midrange – the EBP of 329 underlines that this cone is meant for midrange or horn loading. The driver database and enclosure calculator on 42.audio help with tuning the chamber.
The lower crossover should sit well above 140 Hz, and at the top the range ends at 7,000 Hz. In practice the 6M44 in a three-way cabinet hands over to a dome, a ribbon or a 1" compression driver, sensibly a good way below the upper limit so that the 6" cone still radiates widely in the transition region.
What to look out for
- 8 Ω, Re 5.3 Ω: runs on any amplifier, the 200 W AES are hard to reach in midrange duty.
- 3.4 kg despite 6": the ferrite motor is large, size the cabinet rear and fixings accordingly.
- Mounting depth 85 mm – fits shallow midrange chambers.
- Xmax 2.25 mm: always run with a high-pass, never assign lower-mid duties.
- Le 0.32 mH: flat impedance at the top, a passive crossover works without elaborate impedance correction.
Frequently asked questions
Can I use the 6M44 as a mid-woofer in a two-way cabinet?
No. With Fs 102 Hz, Xmax 2.25 mm and a lower limit of 140 Hz it has no bass capability at all. It is intended as a midrange in three-way systems where a woofer takes over the range below.
How does the 6M44 differ from the 6NMB420?
The 6NMB420 with Fs 110 Hz, Qts 0.33 and Vas 6.1 l is a comparable midrange with neodymium that builds lighter. The 6M44 relies on ferrite and puts more mass into the motor at 3.4 kg. Both drivers are in the 42.audio database for comparison.
How much amplifier power does the midrange need?
Little. At 95 dB sensitivity and a restricted frequency band, only a fraction of the total power lands in the midrange. The 200 W AES are the thermal limit; a channel with a fraction of that is enough in most three-way cabinets.
18Sound 6M44: 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 6M44 is a 6-inch midrange driver with ferrite magnet from the M 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 6M44 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 | 102 Hz |
| Total Q Qts | 0.29 |
| Electrical Q Qes | 0.31 |
| Mechanical Q Qms | 4.4 |
| Equivalent volume Vas | 3.8 l |
| Moving mass Mms | 16.0 g |
| Cone area Sd | 132 cm² |
| Linear excursion Xmax | 2.25 mm |
| Force factor BL | 13.4 Tm |
| DC resistance Re | 5.3 Ω |
| Voice coil inductance Le | 0.32 mH |
Comparable drivers
Same size, same type, Qts within ±30 %.
- 18 Sound 6NMB900fs 95 Hz · Qts 0.32 · Vas 10.3 l · in the database
- 18 Sound 6NMB420fs 110 Hz · Qts 0.33 · Vas 6.1 l · in the database
- 18 Sound 6NMB900fs 100 Hz · Qts 0.34 · Vas 6.65 l · in the database
- 18 Sound 6ND430fs 61 Hz · Qts 0.27 · Vas 12.6 l · in the database
- 18 Sound 6NTLW2000fs 86 Hz · Qts 0.35 · Vas 4.6 l · in the database
- SB Acoustics MR16TX-8fs 35 Hz · Qts 0.31 · in the database
Specifications
| Allgemein | |
|---|---|
| Manufacturer | 18SOUND |
| Category | Mid Frequency |
| Series | M |
| Magnet | Ferrite |
| Impedance (Ω) | 8 |
| Power handling (W) | 200 |
| Sensitivity (dB) | 95 |
| Frequency from (Hz) | 140 |
| Frequency to (Hz) | 7000 |
| Abmessungen & Korb | |
|---|---|
| Diameter | 6 |
| Voice coil (inch) | 1.75 |
| Mounting depth (mm) | 85 |
| Weight (kg) | 3.4 |
| Thiele-Small-Parameter | |
|---|---|
| Re (Ω) | 5.3 |
| Le (mH) | 0.32 |
| Fs (Hz) | 102 |
| Qms | 4.4 |
| Qes | 0.31 |
| Qts | 0.29 |
| Vas (l) | 3.8 |
| Xmax (mm) | 2.25 |
| BL (Tm) | 13.4 |
| Mms (kg) | 0.016 |
| Sd (m²) | 0.0132 |