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Main => Main Forum => Topic started by: Evetsllub on July 04, 2011, 09:20:27 pm

Title: USB power from Laptop - will this work?
Post by: Evetsllub on July 04, 2011, 09:20:27 pm: Hey guys,

I have a few things that need to run through USB. A laptop will be running everything, and i'd like to get away with a passive USB hub if possible to avoid wiring more stuff to a power supply (space is limited, see "Cafe au Cade" project in the projects thread for an idea, it all needs to fit under a coffee table). Plus I have a nice and compact 4 port passive USB hub that i can use.

This is what i need to run through USB:
2 x Ultimarc U360s
1 x Ipac 2 keyboard encoder
1 x USB powered 860w speakers - http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=150600149748#ht_4325wt_888 (http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=150600149748#ht_4325wt_888)
2 x USB ports that will have external access... to hook up keyboard/mouse/USB stick or anything like that.

What do you think, am i risking frying the laptop running all of this stuff? The main issue i imagine are the speakers as the other stuff wont be drawing too much power i wouldn't think.
Title: Re: USB power from Laptop - will this work?
Post by: BobA on July 04, 2011, 09:43:12 pm: Should have no problem with your list but I seriously doubt that those are 860W speakers. USB would have a real problem with them if they are.
Title: Re: USB power from Laptop - will this work?
Post by: Evetsllub on July 04, 2011, 10:04:44 pm: yeah i thought the same thing... just some marketing BS.
Title: Re: USB power from Laptop - will this work?
Post by: lilshawn on July 05, 2011, 01:08:34 am: Quote from: Evetsllub on July 04, 2011, 10:04:44 pm
yeah i thought the same thing... just some marketing BS.

marketing BS??? hell, they aren't even trying. but 860 watts "PMPO"????? (supposedly "peak music performance output") is that into a dead short output for 10 cycles then???... lets see... about a trilliosecond??
Title: Re: USB power from Laptop - will this work?
Post by: MonMotha on July 05, 2011, 06:03:18 am: I think they're saying that their speakers are as loud as if you were to dump 860W (actual, RMS watts) into a resistor.
Title: Re: USB power from Laptop - will this work?
Post by: Blanka on July 05, 2011, 06:16:54 am: Quote from: Evetsllub on July 04, 2011, 09:20:27 pm
1 x USB powered 860w speakers - http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=150600149748#ht_4325wt_888 (http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=150600149748#ht_4325wt_888)
ROFL!!!!!
How does THAT work? 5V @ 500ma means a maximum output of 2.5W RMS. To get 860W......
Does it have a electronic flash capacitor getting to full power, with just 1 chance to release it in 1 ms to the speaker cone, blasting the unit entirely in small pieces?
Title: Re: USB power from Laptop - will this work?
Post by: drventure on July 05, 2011, 07:36:46 am: :laugh2:

Yeah, Note that the ad never says they're 860 watt speakers (as far as I can tell), but rather that designation seems to be used as a "model number" or somesuch.

Those little usb powered speakers are pretty much worthless. I've never heard a pair that sound good.

I'd find a pair of decent amplified speakers without a sub (Logitech, Bose and Altec Lansing sell pretty good ones, and you can usually find deals online for less than 50$).
Title: Re: USB power from Laptop - will this work?
Post by: Evetsllub on July 05, 2011, 09:02:34 am: the sound doesnt have to be real good. space is seriously limited, people playing this arent going to be saying 'damn i wish the sound was better'. they should do the job.