Panasonic SB-C210 HTiB center channel

jr@mac

Yes, you read that correctly. A friend of mine dropped this off claiming it did not work. Well, I ran an impedance sweep on it and determined it sure as shit works. 

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Basic shit construction for HTiB speakers. 3/8" particle board. I pulled the hooker upper piece out, and peeked inside. No damping, no stuffing. Two 3" woofers with tiny magnets, what looks like a cone tweeter with a really dinky magnet. The crossover on the hooker upper piece consists of a 1.5uF NPE cap, a 5 ohm 5 watt resistor and a 100uF NPE cap. 

I decided to measure this, of course. Distortion:



So actually not terrible on the distortion front. The woofers running full range is the biggest culprit in this regards.

On tweeter axis + impedance:



Biggest surprise to me was the nominal impedance is quite high. I would like to think Panasonic used some shit electronics in the provided amplifier if it was determined they needed to wire to 16+ ohm nominal. Or, most likely, they used shit electronics but did not want to splurge to keep 4 or 16 ohm drivers on the shelf so series two of whatever are used in the surrounds. 

Other than the peak at 1700 or so, looks to be fairly well balanced. Since this is a center channel, I wonder if there is a benefit from the increased presence in that range. Seems the built-in highpass, plus the peakiness in that area would emphasis female vocals and suppress male vocals. I do not plan to do any listening tests to confirm or deny that theory. 

I ran a CSD on it, as well:



Looks like it might be trying to phone home it is ringing so much. 

I can't build one of these for what I can buy one of these, that being said - I would not buy one of these anyways. Maybe I will talk to this guy about a DIY setup at some point, or at least get him pointed to a better set of commercial speakers. 

I hope you enjoyed this foray into shit-in-a-box!

Mzisserson

It always amazes me at how close the shit is to being not good, but not shit. like a handfull of stuffing in the cab. But those extra pennies times however many and on and on. 

Fun, thanks.

squamishdroc

  

jr@mac

Mzisserson said:

It always amazes me at how close the shit is to being not good, but not shit. like a handfull of stuffing in the cab. But those extra pennies times however many and on and on. 

Fun, thanks.

Yep - I looked at possibly improving it, but the best improvement would be all new cabinets followed by a real crossover. At which point you may as well upgrade the drivers to at *least* Goldwood/GRS level. 

I have measured a lot of cheap speakers over the years, and almost universally the drivers are generally acceptable (the distortion measurement on this particular model is surprisingly good) but I think I have determined the *real* driver of a cheap speaker is weight (for shipping), hand-in-hand with size (pack as many on a truck with as little weight as possible). So cabinets are undersized and under built. Next thing is limiting crossover networks to as few shitty components as possible. Most of the off-brand or ultra-cheap HTiB offerings, of course, start with cheap, generic drivers - but surprisingly enough, a lot of the Yamaha/Sony/Denon/Onkyo etc use solid drivers. Look at the 8" woofer out of a $150 pair of Sony bookshelf speakers (SS-MB350H), for example:



Then they throw those in a shitty cabinet with a shitty crossover lol. 

Mzisserson

Those Sonys don't look horrible. Venting under the spider, really?!  

jr@mac

Yeah, that's what I thought, too. Plastic frame but still - definite upgrade from flimsy stampered steel. 

I suspect they are pretty high Q though. 

jr@mac

Woofers from a Yamaha something or other. Were pretty nice.