Alpine CDM-9821

CD receiver with CD changer controls

  • Alpine CDM-9821


Item #: 500CDM9821

Review Summary

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Our take on the Alpine CDM-9821

by Robert Ferency-Viars

Why replace your factory radio?

Two good reasons - sound quality and cool features. A new car stereo offers power that's superior to most factory radios, along with more sophisticated tone controls. And most car stereos offer built-in or optional features that add safety and fun to life in your car, including inputs for your iPod or MP3 player, Bluetooth connectivity for hands-free cell phone calls, satellite radio or HD Radio reception, and connections for building an audio system in your car.

Rock your ride with four channels of built-in MOSFET high power from Alpine's CDM-9821 CD receiver! The Bass Engine® feature lets you choose which bass and treble frequencies get adjusted (and how wide or narrow the bass adjustment is), so you get a more effective match to your vehicle's acoustics.

CD-R and CD-RW discs are no problem for this classy deck — it plays your mixes flawlessly. The sensitive MaxTune radio tuner pulls in your favorite AM and FM stations like a champ. Add an Alpine 6-disc CD changer, and your road trips will fly by. You can add extra bass to your car by connecting an amplifier/subwoofer combo to the CDM-9821's preamp outputs.

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  • detachable face
  • MaxTune tuner
  • 12 FM/6 AM presets
  • plays audio CDs, CD-Rs, and CD-RWs
  • Bass Engine (bass center frequency, width, and level, plus treble center frequency and level adjustments)
  • CD changer controls for the CHM-S630 6-disc changer (will control the CHA-S634 6-disc changer with optional M-Bus/Ai-Net cable)
  • optional auxiliary input
  • source tone memory
  • preamp outputs
  • MOSFET internal amp
  • clock
  • 16 watts RMS/45 peak x 4 channels (CEA-2006 Compliant)
  • CD frequency response 5-20,000 Hz
  • CD signal-to-noise ratio 105 dB
  • FM sensitivity 9.3 dBf
  • warranty: 1 year
  • Our 60-day money-back guarantee

Hands-on research from the Crutchfield Labs (what are the Labs?)

Features and Specs
CEA-2006 Compliant ---
RMS Power Output 16 watts
Peak Output 45 watts
RMS Power Bandwidth N/A
Preamp Outputs 2-channel
Sub Preamp Outputs No
Switchable Rear Preamp Outputs ---
Video Screen No
Preamp Voltage 2 volts
Display Color Green/Amber
Key Button Color Green/Amber
EQ Bands None
Wireless Remote No
Steering Wheel Control Compatible ---
Parts Warranty 1 Year
Labor Warranty 1 Year
AUX Input Optional
USB Input ---
Memory Card Slot No
Bluetooth Compatible ---
Satellite Radio Ready No
HD Radio ---
Navigation ---
iPod Compatibility
Full size ---
Nano ---
Touch ---
Mini ---
iPhone ---
FM Sensitivity 9.3 dBf
European Tuning Yes
Seek/Scan Seek
Radio Data System No
Product Research
What's in the box?

Download owner's manual

  • AM/FM/CD/Changer controller receiver
  • Sleeve
  • Face
  • Hard plastic face case
  • Trim ring
  • Wiring harness with in-line fuse/fuse holder
  • 4 ISO-mount screws
  • Owner's Manual (English/French/Spanish)
  • Customer Care Registration card

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team — they open the box, verify contents, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

Changer Controls
Clock Display Note


Bass Engine: Bass Engine functions provide control over your system, so you can tailor the sound to your personal tastes. Bass Engine includes the following functions:

  • Bass Center Frequency Control: To tailor bass response to your preference, you may select the bass control's center frequency. You may select from the following center frequencies: 60Hz, 80Hz, 100Hz, or 200Hz.
  • Bass Width Control: You may choose from four band width (Q-Factor) settings for the bass control; the bass control can be set to affect a wide or narrow band of frequencies.
  • Bass Type: You may choose from the following Bass Type settings: Type 1, Type 2, or Type 3. Type 1 will sound best if you have a subwoofer in your system. Use Type 2 or Type 3 if you are using small diameter speakers.
  • Treble Center Frequency Control: To tailor treble response to your preference, you may select the treble control's center frequency. You may select from the following center frequencies: 10kHz, 12.5kHz, 15kHz, or 17.5kHz.
  • Subwoofer Level Control: The level of the subwoofer preamp outputs can be adjusted to balance the output of your subwoofer with that of your other speakers.

Rear/Subwoofer Preouts: This unit has one set of rear/subwoofer outputs. When set to "subwoofer", the level of the outputs can be adjusted.

Auxiliary Input Ready: With the addition of the optional KCM-122B M-Bus/RCA interface cable, the audio from an auxiliary source can be played through this unit. When the KCM-122B interface cable is used, a CD changer cannot be connected to the head unit.

Changer Controls

Compatibility: This unit is compatible with 6-disc Alpine M-Bus CD changers. Using the optional M-Bus/Ai-NET compatible cable (KCA-130B), this unit can control the CHA-S634 Ai-NET 6-disc CD changer.

Clock Display Note

Clock Operation: This unit allows you to choose "keyed" or "unit on" clock operation. When the clock has been given display priority and the unit is turned off, the clock will be displayed whenever the ignition key is in the "on" or "accessory" position. If the clock is not given display priority, the clock is not displayed when the unit is off.

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Alpine CDM-9821 Reviews

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4 out of 5

Nice reciever

Written By red666, Bennington, NE on Thursday, March 10, 2005
I have found this reciever very nice!It is great if you listen to any kind of music. I mostly listen to rock,metal,hardcore,etc. and it is really great reciever.It fits well and sounds excellent with my 4 4x6 speakers plus my 10"subwoofers that is run on a Rockford amp that powers 900 watts.Excellent choice if you are just starting out in putting an after market stereo in your veichle that is somewhat around your price rang.I have had this reciever over a year and it is a great reciever. There is one problem I do have with it whenever I put a new CD in and have it in there for a long period of time of playing it wont come out but that is easily over comed.
25 out of 34 people found this helpful
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For a more in-depth review and enhanced detailed information on the Alpine CDM-9821, please visit the Crutchfield website product page (/ISEO-rccbcspd/p_500CDM9821/Alpine-CDM-9821.html ).