Main > Audio/Jukebox/MP3 Forum
Using car speakers in a cab
Dr. J:
--- Quote from: AlanS17 on February 18, 2003, 10:28:37 pm ---I've had plenty of problems with unshielded speaker magnets. I personally think a good set of computer speakers is ideal. Nobody is gonna see them anyways. They'll never know.
--- End quote ---
Not unless you want them too ;D
BTW, I haven't had any problems with the magnets. I just kept them away from the PC and the monitor.
JoeB:
But what about the fact that almost all power supplies for PC's out there are SWITCHING power supplies? (hence can't really supply the rated wattage at a constant rate for a long period of time) ???
e.g. saying one has a 300W power supply might in reallity have only a 150-200W constant PSU. To top it off, since it is 12V (and not 14 like a real power supply, which by the way, my 30$CDN got me a brand name) will require a higher current to hit the same wattage as a real 14v psu! GET IT? You might think your pushing a certain current, but in reality, require a lot higher current to get the same wattage.. a higher current which might damage the car amp!
To top it off, I've never seen a PC power supply that monitors its own temperature, and resets itself during spikes and what not...
Sure, some people would go with a PC because they have it around, but in no means is it close to being the best thing (nor the cheapest!) Heck, look at eBay.. if you're in the US, you can get some really sweet deals on very good PSU's for dirt cheap!
And for those of you with really big amps, that want to push 2 speakers and a couple of car subs.. a dedicated PSU (non-PC) is your *ONLY* choice.. so why not make it right from the start???
LK
Tehrasha:
--- Quote from: JoeB on February 19, 2003, 03:25:03 pm ---But what about the fact that almost all power supplies for PC's out there are SWITCHING power supplies? (hence can't really supply the rated wattage at a constant rate for a long period of time) ???
e.g. saying one has a 300W power supply might in reallity have only a 150-200W constant PSU.
--- End quote ---
There is no almost about it. All PC PSUs are switching types.
A 300 Watt powersupply is 300Watts but that is across all of voltages. +12 and +5
So yes, a 300 Watt supply may only put out 200 Watts to its 12v side. And unless you are playing a 1KHz tone at full volume, you arent going to be pulling those kinds of current levels for more than a couple hundreths of a second anyway.
A math lesson and a dirty little secret about car amplifiers.
12v (car battery)... ok, for argument, ill use 14v.
14 volts from the car connected raw to an 4 ohm speaker will draw 3.5 Amps.
14 volts at 3.5 Amps is 49 Watts. So how do car amplifers manage to crank out things like 100, 200, 500 even 1000 Watts per channel??? :o
Each one has a switching powersupply inside it, bringing the 12..er 14 Volts up to whatever it needs.
--- Quote ---To top it off, since it is 12V (and not 14 like a real power supply, which by the way, my 30$CDN got me a brand name) will require a higher current to hit the same wattage as a real 14v psu! GET IT?
--- End quote ---
I got it from the beginning, what is your problem? You seem to be obsessed with WATTAGE and loudness. Yes, my setup under an ideal power situation should be capable of 80W/channel into the main speakers and 150W/channel into the subwoofers. But I value my hearing to much to want to stand 12" from that while playing games.
--- Quote ---You might think your pushing a certain current, but in reality, require a lot higher current to get the same wattage.. a higher current which might damage the car amp!
--- End quote ---
Current is the limiting factor for the PSU. The car amplifier cannot suck more (possibly damaging) current out of a supply than the supply can provide.
Reasonable listening volume will never come close to that kind of level, let alone the rating of the car amplifier or PSU.
--- Quote ---To top it off, I've never seen a PC power supply that monitors its own temperature, and resets itself during spikes and what not...
--- End quote ---
Odd, we just had a posting from a fellow whose PSU cut him off at high output levels. By the very nature of switching supplies, spikes have little effect on output.
--- Quote ---Sure, some people would go with a PC because they have it around, but in no means is it close to being the best thing (nor the cheapest!) Heck, look at eBay.. if you're in the US, you can get some really sweet deals on very good PSU's for dirt cheap!
--- End quote ---
Last I knew 'free' was cheaper than $anything. As for the 'best thing', I dont think anyone in this thread has said that PSUs were a best choice. They were simply one solution to a question. They have their problems, as do standard 'real' power supplies.
--- Quote ---And for those of you with really big amps, that want to push 2 speakers and a couple of car subs.. a dedicated PSU (non-PC) is your *ONLY* choice.. so why not make it right from the start???
--- End quote ---
Why mess with powersupplies and amps? For that kind of volume and power output the best choice would be a home stereo rig.
As with most ppl building cabinets, we deal with what we have available.
And custom, kludged, hacked, slashed, mangled, spindled, and dare I say 'unique' solutions are par for the course.
--Teh
Tune in next week when I tell about the switching supplies inside the cockpit displays that I repair for a living. (and I dont mean arcade cockpits)
Dr. J:
--- Quote from: Tehrasha on February 19, 2003, 05:27:36 pm ---As with most ppl building cabinets, we deal with what we have available.
And custom, kludged, hacked, slashed, mangled, spindled, and dare I say 'unique' solutions are par for the course.
--- End quote ---
Amen to that. I didn't have a clue how to "professionally" do any of this stuff. I just rigged up the best I knew how with some help from friends and here.
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