B&W CM8 powered by Logitech PC sub amplifier - AVS Forum
Speakers > B&W CM8 powered by Logitech PC sub amplifier
almalino's Avatar almalino 04:31 AM 02-25-2013
Dear experts!

I want to upgrade my sound system on my HTPC.

Currently I use:
Logitech Z-5450 5.1 Wireless Speakers
http://www.pcmag.com/article2/0,2817,1904833,00.asp



I want to start replacing parts of the system with better speakers and amplifier. I cannot buy all at once due to budget.

Do you think I'm crazy If I buy 2 front towers as a first step B&W CM8 and attach them to Logitech amplifier instead of current small Logitech L&R satellites.


Logitech amplifier is:
Total RMS power: 315 watts RMS
Tech Specs Satellites: 199 watts RMS (2 x 38W front, 2 x 40.5W rear, 42W center)
Tech Specs Subwoofer: 116 watts RMS
Tech Specs Total peak power: 630 watts
Tech Specs Maximum SPL: 103 dB
Tech Specs Frequency response: 35 Hz - 20 kHz
Tech Specs Input impedance: 9,500 ohms
Tech Specs Amplifier: Ultra-linear high-capacity analog
Tech Specs Drivers: Satellites: 2 1/2” aluminum phase plug driver
Tech Specs Band-pass subwoofer: 6 1/2” high-excursion driver
Tech Specs Surround sound effects: Hardware decoding for Dolby Digital, DTS and DTS 96/24 soundtracks
Tech Specs Dolby Pro Logic II (Movie and Music modes)
Tech Specs 6-channel direct
Tech Specs Supported digital formats: Dolby Digital, DTS and DTS 96/24
Tech Specs PCM (uncompressed stereo): 44.1 kHz/16 bit through 96 kHz/24 bit
Tech Specs Source inputs: (2) Digital optical for DVD or CD players, PlayStation2, Xbox, or PC sound cards (requires optical cable, sold separately)
Tech Specs (1) Digital coaxial for DVD or CD players or PC sound cards (requires coaxial cable, sold separately)
Tech Specs (1) 6-channel direct (3 stereo-mini connectors) for 2, 4 or 6-channel PC sound cards OR
Tech Specs (3) stereo-mini connectors for 3 stereo analog audio sources, such as CD and DVD players, PlayStation2, Xbox, or 2 channel PC sound cards (some devices may require stereo mini to dual RCA adapter, sold separately)
Tech Specs (1) Analog stereo-mini (on side panel of control center) for portable CD, MP3, or MiniDisc® players

warpdrive's Avatar warpdrive 08:23 AM 02-25-2013
I wouldn't do it. I just don't know how that Logitech amp will handle the load of the B&W. The B&W is rated with impedance down to 3 ohms which is a fairly difficult load for even an expensive amp. If the Logitech amp is overloaded, it may cause all kinds of distortion.
arnyk's Avatar arnyk 08:38 AM 02-25-2013
Quote:
Originally Posted by almalino View Post

Dear experts!

I want to upgrade my sound system on my HTPC.

Currently I use:
Logitech Z-5450 5.1 Wireless Speakers
http://www.pcmag.com/article2/0,2817,1904833,00.asp



I want to start replacing parts of the system with better speakers and amplifier. I cannot buy all at once due to budget.

Do you think I'm crazy If I buy 2 front towers as a first step B&W CM8 and attach them to Logitech amplifier instead of current small Logitech L&R satellites.


Logitech amplifier is:
Total RMS power: 315 watts RMS
Tech Specs Satellites: 199 watts RMS (2 x 38W front, 2 x 40.5W rear, 42W center)
Tech Specs Subwoofer: 116 watts RMS
Tech Specs Total peak power: 630 watts
Tech Specs Maximum SPL: 103 dB
Tech Specs Frequency response: 35 Hz - 20 kHz
Tech Specs Input impedance: 9,500 ohms
Tech Specs Amplifier: Ultra-linear high-capacity analog
Tech Specs Drivers: Satellites: 2 1/2” aluminum phase plug driver
Tech Specs Band-pass subwoofer: 6 1/2” high-excursion driver


I don't know how the satellites are connected to the place where the power amps are (probably the sub) but once you disconnect them, you can do a simple check on them that might even be a good go, no-go indication.

Just measure the resistance of each satellite speaker at its speaker lead using an ohmmeter. You can get inexpensive ohm meters at electronics and also big home improvement stores for under $30.

If the resistance you measure is between 2 and 6 ohms then this might even work out. If it is higher than 8 ohms, then not so much.

The other potential problem is that the power amp for the satellites may have some built-in equalization to optimize the performance of the satellites. Sorry about that - do what you can with tone controls.
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