CELESTION CF0820M
CELESTION CF0820M — 8" / 8 Zoll · Tieftöner · Ferrit
250 W AES - 98 dB - 150 – 6000 Hz - 8 Ω
Art.-Nr.: 42A-CHS-TT-CEL-0003
Documents
CELESTION CF0820M — 8" · Tieftöner
8-inch, cast aluminium chassis, ferrite magnet midrange driver
250 W AES · 98 dB Empfindlichkeit · Frequenzbereich 150 Hz – 6000 Hz
Merkmale
- Dedicated midrange driver
- Copper sleeved pole reduces HF inductive rise
- Narrow edged chassis for close packing
- Airflow vented for dynamic heat dispersion
Technische Daten
- Durchmesser: 8 "
- Schwingspule: 2 "
- Belastbarkeit: 250 W
- Dauerbelastbarkeit: 500W
- Empfindlichkeit: 98 dB
- Impedanz: 8 Ω
- Magnet: Ferrit
- Chassis: Aluminium-Druckguss
- Membran: Imprägniertes Papier
- Sicke: Gewebeversiegelt
- Aufhängung: Einfach
- Schwingspulenträger: Glasfaser
- Schwingspulendraht: Kupferkaschiertes Aluminium
- Gewicht: 3.4 kg
- Einbautiefe: 113 mm
- Ausschnitt: 187mm / 7.4in
- Frequenzbereich: 150 – 6000 Hz
Thiele-Small-Parameter
- Fs: 202 Hz
- Qts: 0.567
- Qms: 1.784
- Qes: 0.831
- Vas: 2.12 l
- Xmax: 3.5 mm
- BL: 13.27 Tm
- Re: 5.39 Ω
- Le: 0.12 mH
- Mms: 0.0214 kg
- Sd: 0.0227 m²
Datenblatt (PDF) · Herstellerseite
Artikel-Nr: 42A-CHS-TT-CEL-0003
Celestion CF0820M: 8" midrange with 98 dB and a narrow frame for tight packing
Within the CF series, the Celestion CF0820M is the 8" driver dedicated to pure midrange duty. A rated band of 150 to 6000 Hz, 98 dB sensitivity at 8 Ω and 250 W AES on a 2" copper-clad aluminium voice coil speak plainly: high efficiency, little excursion, plenty of dynamics in the vocal range. The impregnated paper cone sits in a cloth-sealed surround, and the cast aluminium frame has a deliberately narrow rim so several drivers can sit close together side by side or stacked.
The parameters confirm the design intent: Fs 202 Hz, Vas only 2.12 l, Qts 0.567, Xmax 3.5 mm and a moving mass of 21.4 g driven by 13.27 Tm. The inductance of 0.12 mH is strikingly low, a result of the copper sleeve on the pole piece; this keeps the impedance flat well into the presence region and makes a clean passive crossover easier. The vented magnet carries coil heat away during continuous operation.
Use and enclosure
The CF0820M belongs in a sealed midrange chamber, not in a vented box. The guideline from the parameters is 3.8 l with an in-box resonance of 252 Hz; in such a small volume the driver is tightly damped and delivers the midrange punch it was built for. Cross over at the bottom well above the in-box resonance so the cone is not working near resonance in the overlap region, and at the top below the 6000 Hz rated limit to a compression driver on a horn from Celestion's horns and waveguides category.
The narrow frame rim points to line arrays and columns: the closer the centres of several 8" midranges sit, the higher you can push vertical directivity without side lobes. At 113 mm mounting depth, a 187 mm cut-out and 3.4 kg even a four-driver module stays manageable. At 98 dB a small amplifier is enough; Re 5.39 Ω is a benign 8 Ω load.
What to look out for
- Pure midrange: Fs 202 Hz, Vas 2.12 l, sealed chamber around 3.8 l.
- Le 0.12 mH: very flat impedance through the midrange, simple passive crossover.
- Xmax 3.5 mm: set the high-pass well above the 252 Hz in-box resonance.
- Narrow frame rim: tight driver spacing for arrays and columns.
- 113 mm mounting depth, 187 mm cut-out, 3.4 kg.
Frequently asked questions
Can the CF0820M reproduce bass as well?
No. Fs 202 Hz, Vas 2.12 l and an EBP of 243 are the figures of a midrange driver; below its rated band starting at 150 Hz a woofer has to take over. In return it delivers 98 dB in the midrange, considerably more level per watt than a bass/mid driver such as the CF0820BMB.
How large does the midrange chamber need to be?
As a guideline about 3.8 l sealed, giving an in-box resonance around 252 Hz. Damp it well and avoid a rear wall parallel to the cone, and the midrange stays clean.
Why is the inductance so low?
The copper sleeve on the pole piece acts as a shorting ring and pushes Le down to 0.12 mH. That reduces the impedance rise and distortion towards high frequencies; in practice it means less correction work in the crossover and a more even response up to the crossover point.
At 42.audio you get the CELESTION CF0820M with all key data in the driver database and the enclosure calculator. More drivers from this manufacturer: Atlas Celestion.
Specifications
| Allgemein | |
|---|---|
| Manufacturer | CELESTION |
| Category | Low Frequency |
| Series | CF |
| Magnet | Ferrite |
| Impedance (Ω) | 8 |
| Power handling (W) | 250 |
| Sensitivity (dB) | 98 |
| Frequency from (Hz) | 150 |
| Frequency to (Hz) | 6000 |
| Abmessungen & Korb | |
|---|---|
| Diameter | 8 |
| Voice coil (inch) | 2 |
| Mounting depth (mm) | 113 |
| Weight (kg) | 3.4 |
| Thiele-Small-Parameter | |
|---|---|
| Re (Ω) | 5.39 |
| Le (mH) | 0.12 |
| Fs (Hz) | 202 |
| Qms | 1.784 |
| Qes | 0.831 |
| Qts | 0.567 |
| Vas (l) | 2.12 |
| Xmax (mm) | 3.5 |
| BL (Tm) | 13.27 |
| Mms (kg) | 0.0214 |
| Sd (m²) | 0.0227 |