Am I crazy? B&W CM8 powered by Logitech sub

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 satellites.

Logitech amplifier is:
Total RMS power: 315 watts RMS, Satellites: 199 watts RMS (2 x 38W front, 2 x 40.5W rear, 42W center),Subwoofer: 116 watts RMS,Total peak power: 630 watts,Maximum SPL: 103 dB,Frequency response: 35 Hz - 20 kHz,Input impedance: 9,500 ohms,Amplifier: Ultra-linear high-capacity analog,Input impedance: 9,500 ohms,Amplifier: Ultra-linear high-capacity analog,Drivers: Satellites: 2 1/2 aluminum phase plug driver, Band-pass subwoofer: 6 1/2 high-excursion driver,Surround sound effects: Hardware decoding for Dolby Digital, DTS and DTS 96/24 soundtracks,Dolby Pro Logic II (Movie and Music modes) - 6-channel direct,Dolby Pro Logic II (Movie and Music modes) - 6-channel direct,Source inputs: - (2) Digital optical for DVD or CD players, PlayStation2, Xbox*, or PC sound cards (requires optical cable, sold separately) - (1) Digital coaxial for DVD or CD players or PC sound cards (requires coaxial cable, sold separately)

That seems like a poor proposition, the power numbers on that logitech set are most likely way overinflated. Last thing you want to do is drive the amp too hard and clip it---> square wave to new expensive speakers---->blown speakers.

Honestly, it would probably work just fine as long as you aren't crazy with your volume levels or expectations. Your next upgrade though should probably be a decent receiver.

I like the speaker choice, but those CM8s are about 2200+ USD for a pair. There's simply no way I'd connect those to a multimedia combo sub/amp. If it were me, I'd feel a lot more comfortable even with a reasonably humble receiver.

I'm not sure where you're located, but, several days ago Denon and Onkyo direct were both offering 20% off + free shipping. The sales could still be running. More info here.

For a second, lets assume the rating on the amp is correct.

The speakers handle "Max power handling (watts) 150"
I am unsure if this is a music rating, or a thermal rating, but assume it is thermal.

The amp can put out "2 x 38W front".

I retract my earlier statement, even sending a clipped signal there is very little chance you will damage your speakers, but if you drive the amp that hard to get decent listening levels, they will likely sound like junk.

I know I may sound like a broken record but I am an evangelist for these speakers. Check out the Magnepan MMG's they can be had significantly cheaper than the speakers you are looking at, and then you could afford a decent receiver/amp and sub and still end up spending less money. I have had quite a few speaker setups in the last 20 years, I ended up selling these: http://www.klipsch.com/lascala-floorstanding-speaker after hearing the MMG's. The La Scala's were significantly more expensive.

If you are dead set on the speakers you linked, I would suggest waiting until you can afford to upgrade all at once, a system is only as strong as the weakest link.

www.magnepan.com

Please don't.

if your willing to spend that much money on speakers don't be cheap and get an amp first or just get an amp period.

this is basically like saying should I buy a Mercedes E55 AMG and then run it with the Doughnut spare tire all the time...

basically yes that would be insane.. to have such speakers just hobbled by the crappy amp built into a Logitech MM sub.

Thank you everyone for opinions I have an offer to get a pair of used for 900 Euros. So, it is not that expensive. Later I will add a good amplifier for sure!

Just buy the speakers now and wait until you have a half-decent amp before you hook them up. They won't go bad just sitting there.

ok the high pass on the logitech set up is going to be somewhere in the neighborhood of 150hz.

You can pick up a stereo amp for $50 or less used, just pick up an old and cheap one and upgrade it down the line.

Yes that's crazy.

BUY those and an amp and receiver.

It is more common to destroy speakers with a low-powered amplifier driven into clipping (sudden death, requiring driver replacement and sometimes taking the amp out at the same time) than it is to fry speakers driving them with too much clean power (typically first indicated by the very distinctive sounds of the speakers reaching their excursion limits).

Even assuming the Logitech's ratings are accurate, they're meaningless without knowing the impedance they're being quoted at. If it's 2 ohms then that'll translate to about 8.5 watts at the 8 ohm nominal rating on the B&W, which given their lower sensitivity will mean cranking the amp to get reasonable volume (risking clipping and increasing the chance for damage). And if the Logitech is rated for 16 ohm speakers it may not be stable into 8 ohms (less chance of this, but it exists).

Do yourself a favor, get an amp/receiver rated for 8 ohm speakers (most will be, it's lower impedance that tends to cause issues).

Get a $200 receiver it will sound fine. The problem with the sub is it has a super high 200hz crossover (im estimating but thats why logitech sounds like shit), so your B&W CM8 will sound like muddy junk.

Buy the speakers and set them aside until you can provide a decent signal.

yeah.. buy them and get decent proper amp or receiver


I for example have just recently bought this for $10 - Nikko NR-750 (circa 1987~ish receiver 55WPC ) that is relatively compact for a receiver and is doing a fine job driving a pair of Bang & Olufsen RL 60.2 speakers

pictured as so..







Now I'm not claiming this would be any stretch be the penultimate receiver to run those B&W's with but it would be a far sight better than a logitech subwoofer's amp ...


if you go used be sure to check the DC offset values / test with speakers you don't care about before hooking some nice / expensive speakers up to it.

quite a bit a decent stereo gear can be had fairly cheaply around here w/ luck and looking.


That Nikko was in pretty nice shape for $10 (perfect operational condition / little wear on silkscreening by model number and a scratch or to on the top of metal case.)

PC speakers have pretty intense EQ on their amplifiers to make up for their terrible frequency response and small size. I would never use one to power some regular speakers unless I absolutely had to do so. Even a $5 craigslist special stereo receiver will sound better.

D-EJ915 said:

PC speakers have pretty intense EQ on their amplifiers to make up for their terrible frequency response and small size. I would never use one to power some regular speakers unless I absolutely had to do so. Even a $5 craigslist special stereo receiver will sound better.

Click to expand...

This.

CM8s are considered to be mid tier speakers. so connecting components of entry level is lowering the quality of the speakers and worst you aint getting the full experience.

In regards to Audio your system will only sound as the weakest link.

Look for nakamichi stasis amps...designedy nelson pass, can be ad for relatively cheap.