Car Speakers with PC audio amp?

[KevSteele]

I've got a question about using car speakers with a PC amp unit.

I'm not an audio expert, but I did get lucky with my first cab, as I simply took a cheap PC speaker set (Creative Inspire 2.1), and just spliced my existing 6" arcade speakers in as the satellite speakers. Everything worked great.

This time, I thought I'd go the same route, but instead bought some car speakers since I didn't have any original arcade speakers. I spliced the car speakers in, and got nothing this time except for some buzzing.

I suspect it's just a power level issue, as the Creative amp is only rated for 6 watts RMS per satellite, and the car speakers are 35 watts (160 watts max). Pretty big difference. Both the car and PC speakers were 4 ohms impedence, so I've got a match there. I've also checked the polarity for the wires.

Do I just need more "oomph" to drive the speakers? Would a car amp be a better solution, or a more powerful PC 2.1 speaker set? Any other route to take?

The goal here is to find some nice 5" speakers that would fit into the new cab. I'm not too picky on how they're driven, but it would be nice to have some sort of volume control pod (like I currently have with the Create 2.1 speakers).

Any ideas?

Kevin

[RedSquirrel]

heh, this thread has been done twice within the past week  

anyway, it should be possible.

I had a pair of pc speakers i had never used. I opened them up and discovered it was 3w rms. I tried some old car speakers and it worked. I then went and bought a brand new pair of decent car speakers and they also work fine. Sound is pretty good, good enough for mame etc and good enough for mp3s etc as long as its not played too loud.

[KevSteele]

Yeah, I actually searched and found the previous thread.

That's why I'm surprised I'm not getting any sound (other than buzzing) out of the car speakers I'm using. But other than the wattage difference, I'm not sure what else I need to be doing.

I've had some suggestions to use an AM/FM receiver unit as the amp, along with a 3.5mm to RCA Y-adapter cable from Radio Shack. It's a possibility, but I'm curious how many others here have used car speakers successfully.

Kevin

[Cisco Kid]

... a 200W car amp should do the trick (45W rms) and "Computer Stereo Audio to Stereo Receiver" Monster cable  

... and a power supply to power the amp (minimum 20A) ... really only need 15 - 16A

that should do it (if the speakers are unshielded ... you'll need to attach a cancellation magnet to the back on them)

[Nightfalls]

For my future cabinet, I'll be using this model--> http://uk.europe.creative.com/products/product.asp?prod=374

It's pretty expensive, but it's so poweful! BTW, do you know if there will be any problem if a big subwoofer like this is placed too close to the monitor? Satellite spekers are magnetically shielded, but I don't know about the subwoofer. It will be right below, since it's a sit-down cabinet. Any kind of material I could use to prevent the monitor from magnetization?

[MaximRecoil]

Have you verified that the car speakers are functional? I assume that the Creative amp has been verified as working properly. You need to do some trouble shooting. There is no reason why a set of functional car speakers should not work with a functioning amp assuming that everything is hooked up properly. A speaker is a speaker. There is no difference in the functionality or application of a car speaker vs. a home speaker. You have a basket, motor (voice coil and magnet assembly), tinsel leads, cone and a surround.

Traditionally, home speakers have an 8 ohm impedance while car speakers have a 4 ohm impedance although this is hardly set in stone. Also, impedance really is not much of an issue although you don't really want to go lower than what the amp is rated for. Going higher (ie: 8 ohm speakers with a 4 ohm rated amp) is fine, although this will halve the power output of the amp. Music is dynamic anyway so the amp, while it may see a nominal impedance of 4 ohms when running 4 ohm speakers, will see actual impedances that jump all over the place.

In regards to the things that you have mentioned:

6 watts per channel going into car speakers rated for 35 watts RMS (root mean squared) = not a problem at all.

Impedance: Make certain that your amp is rated for 4 ohms (double check those original speakers to make sure that they are 4 ohm speakers). This would still not cause a buzzing sound, but running your amp at too low of a nominal impedance will shorten its life.

Use of a car amp: Not a very practical idea unless you have an inverter. Car amps want 12-14.4 volts and good quality inverters are expensive (the kind that they use in car audio shops for their display models). Plus, as I mentioned before, a speaker is a speaker. Car amps will power home speakers and home amps will power car speakers; it makes no difference (know what you are doing when it comes to impedance of course).

Polarity: Not much of an issue. Reversing the polarity on some speakers will cause them to sound different (some you will hear little to no difference, such as with a typical subwoofer) but it would not cause a buzzing noise.

My guess would be that you are getting some sort of interference from somewhere. Try moving cables and wires around. I have a set of PC speakers that will buzz if the wires get all jumbled with the other PC wires. Also, check for shorts and loose connections.

There is nothing inherently wrong with what you are doing with the car speakers to home amp thing. You just need to trouble shoot. Either something is broke or you are getting interference or whatever.



 

[KevSteele]

Maxim,

I just did a speaker test, and wired the car speakers to my home stereo -- they sounded fine, and worked as expected.

Next, I verified the impedence of both the original PC speakers and the car speakers, and they're both at 4 ohms.

What I'm getting is just a gentle hum on the car speakers when the amp in the subwoofer is turned up to max. No hint of sound or music, even with the polarity reversed.

I'll do some more troubleshooting, but I'm still leaning towards the theory that there's just not enough power being sent to the speakers, or that the speakers are somehow overloading everything.

That said, I am an audio novice and I reserve the right to be completely, utterly, dumbfoundingly wrong.  

I might just buy a more powerful PC amp tomorrow and see if it solves the problem.

Kevin

[MaximRecoil]

Very strange. If your amp really does put out 6 watts per channel, that is enough. That is about the same amount of power that a typical factory head unit in a car puts out. Even the "high powered" after-market head units only put out between 12-17 watts per channel RMS on average despite many of their lofty claims.

Just to be sure that I am following you; you can hook up the original speakers and they work fine, and then moments later hook up the car speakers and they only hum with no music or sound effects at all?

You are doing this with a 2.1 set of PC speakers? I have a 2.1 set of speakers on this PC and the amp is on the back of the subwoofer enclosure. There is a heavy cord coming out of the amp (connected to the amp with a round 10 pin plug) and it leads into the back of the right satellite speaker. Then the right satellite speaker has two smaller wires coming out of the back. One connects to the left speaker and the other connects to the sound card on the PC.

Now, if your speakers are set up like mine then there could be something that you missed when you took them apart and hooked up the car speakers. This is going to work differently than connecting a regular component amp (or home receiver) to a pair of speakers. My right speaker has a volume control and headphones jack. This means that there is a simple preamp in there. Does your PC speaker set have a preamp like that? Anyway, it seems kind of complex the way that PC speakers are wired and I have never taken a set of them apart. I would double check though to make sure that the only thing that you are changing is the speakers and that you are not missing anything. From what you said, you are attempting to adjust the volume from the knob on the sub's amp. If your speaker set is like mine, that will only adjust the subwoofer volume because the volume control for the channels of the amp that power the satellite speakers is up on the left satellite speaker itself. I'm just guessing here though because I don't know what you have for a speaker set and I don't know exactly how you have it rigged.

BTW, here is how you can prove to yourself that 6 watts is plenty to make sound through those car speakers. If you have a multimeter (or a volt meter) take and hook the car speakers up to the home stereo again. Start with the volume all the way down and the voltage across the speaker terminals should read 0 or maybe slightly above 0 if the volume isn't completely down. Then slowly turn your volume up until you reach 5 volts across the speaker terminals. That will be your 6 watts (6.25 watts actually) for a 4 ohm speaker. I promise you that by the time you reach 5 volts you will hear them fine. Watts = Voltage^2 / Impedance so in your case it will be 5v^2 which is 25 divided by your impedance of 4 which is 6.25 watts.

As a side benefit of doing that test you will also get to see just how little watts actually need to be fed to a speaker before you start to hear something. I have a feeling that your home stereo will start to make sound come out of those car speakers that you can hear faintly before you get to 1 volt (.25 watts for a 4 ohm speaker).

[KevSteele]

Maxim,

Yup -- I can plug in the PC speakers into the PC Subwoofer, and it sounds fine, if I plug in the car speakers, nada.

Just to clarify a bit: the PC subwoofer has the amp unit inside, and on the back are two female RCA-style plugs. I've spliced some RCA male plugs onto the ends of the car speakers, and plug them into the subwoofer.

That's one of the reasons I first thought that the polarity might be an issue, so I re-wired one of the speakers, switching the connections at the speaker end. No improvement.

And yes, I can plug the PC speakers in and I get sound. Plug the car speakers in, and just a faint buzz.

I'll give the voltmeter a whirl today. This is too weird...

Kevin

[SS427]

Use of a car amp: Not a very practical idea unless you have an inverter. Car amps want 12-14.4 volts and good quality inverters are expensive (the kind that they use in car audio shops for their display models).

You can also use a stand alone computer power supply instead of an inverter setup.  atx550w,,,20 bucks on ebay,,,,,,,,works great so far (amp and two 8" subs and two 4" speakers below the marquee)

ss

[KevSteele]

Okay, it's "embarrasing true confessions" time...

I ran the voltmeter on the stereo, got about 6 volts output. Tried the PC amp outputs, got nothing...Decided that the PC speaker system had probably died. To make sure, I pulled it all out and took it over to another PC.

Surprise, the PC amp worked fine -- in fact, everything worked fine, including the car speakers!

Okay, now I'm thinking that I've somehow blown the onboard audio chip on my motherboard. I go back and check the volume settings, just to be sure.

Everything looks good, all the sliders are at reasonable levels, and...wait, what's that little checkbox? "Mute All"? Why is that checked? Aw, &*#$!

Bottom line is that everything is working great now, except possibly for my apparently malfunctioning wetware that caused this whole screwup to begin with!

Thanks for the help, though!  

Kevin

[MaximRecoil]

Glad you got it straightened out. I think we all have stories that we could tell like that. Missing something obvious is very easy to do.

[MaximRecoil]

Use of a car amp: Not a very practical idea unless you have an inverter. Car amps want 12-14.4 volts and good quality inverters are expensive (the kind that they use in car audio shops for their display models).

You can also use a stand alone computer power supply instead of an inverter setup.  atx550w,,,20 bucks on ebay,,,,,,,,works great so far (amp and two 8" subs and two 4" speakers below the marquee)

That depends on the car amp. For a small one a big computer power supply can work but I tend to deal with amplifiers that pull 150 amps or more and put out 60+ volts across the terminals.

Let's say that you want a 100w x 2 @ 4 ohms car amp in your cab which is a pretty average size and comparable to the size of a typical home stereo receiver (in regards to power). The PC power supply will be supplying it with 12vdc. You would need a 17 amp power supply to support 200 watts. It is hard to know how much amperage a PC power supply will put out to its 12 volt rails because it also has 5 volt rails and 3.x volt rails so the total rating for the power supply is all of those combined.

This topic comes up fairly often on the car audio forums so I'll quote a post dealing with the similar topic of someone asking about using car amps for home theater:

The problem with computer power supplies is that there is no one regulating them. If you come anywhere near the maximum output potential of an ATX power supply it will fry, and often catch on fire. Do not play without an extinguisher around.

I don't know which one it is, but tomshardware.com found one power supply that was able to actually output about 85% of its max power before it shut itself down. All of the tests were done by takeing an XXX watt power supply and pulling as much current off of each line as possible and then calculating the power with (current * 5v) + (current * 12v) .... and trying to get to the rated 650 watts or whatever. None of them made it, but one was close.

I work for an ATM manufacturing company and we have an ATM which is WinNT based. The power supply in the ATM for the PC is an ATX power supply, 250 watts. It is rated at 16 amps on the 12v line, when I tried to pull 11 amps on that line for a thermal printer, the output dropped to 7.7 volts. We had to change printers from a 12v@11 amps to a 24v@7 amps and use a different power supply.

I would highly suggest not using an ATX power supply to run a home theater on. They already can't handle their "rated" power, so I'd hate to see what would happen when you put a non-constant load on it like a car amplifier.

As for tricking an ATX power supply into working without a motherboard, IIRC, its as simple as shorting two of the wires together.

[SS427]

Sorry, for the bright red background,,,,wasn't what I was expecting it to come out as when I picked shadow.

As far as the amp,  anything pulling that kind of amperage would be way to much for a computer power supply.  For consideration though on mine I was just wanting decent sound, but nothing that would rattle my cabinet apart and I had an old cheap amp laying around anyway.  Haven't tested the powersupply I got (rated at 24amps at 12volts), but that's been working fine for me (I;ll try to check when I get a chance).  Cost for me was the deciding factor (less than $50 for the speakers and power supply) were an inverter alone is significantly more costly.

From what I've searched and found it looks like the options are computer speakers, car speakers w/computer ps, car speakers w/inverter.  Cancellation magnets may or may not be needed depending on field strength an proximity to screen.

Kevin, (OT), I've been delayed on the led's, but when I get them I will get with you on shipping,,,

ss

[KevSteele]

SS427:

(OT: No problem about the LEDs. Whenever is fine.)

I don't have any obvious magnetic interference with the D9200 monitor, so I'm assuming I don't need cancellation magnets.

Sound is great from the car speakers I bought, and as a bonus the cones on the speakers are a translucent red plastic -- I'm already working out ways to illuminate them from behind!  

Kevin

[PileOfMonkeyCrap]

The simple is to use a car amp to power car speakers.  You'll also just need an AT power supply to supply the 12v power to the amp.  Make a simple wiring harness from a PC harddrive/CD drive "Y" power cable and you can also use any 12v or 5v auto accessories.

The picture below shows a custom marquee with 2 Sony Xplod car speakers, a 200w car amp mounted in the middle and a 5v car alarm scanner (ala Kight Rider) mounted beneath them.  All is powered by a 300w AT PS and 1 custom wiring harness.

You'll get the best sound and loudest sound with no distortion.  Additionally, since the amp has subwoofer connections, there is a car tube subwoofer inside the cab to provide earth shaking bass.

All audio connections (TV, Dreamcast, PC, etc) pass thru the New-Q PC equalizer installed in the PC.  This came with a remote and FM tuner.  So all sound can be controlled via the remote, which is great when using the cab for a jukebox, watching music videos, TV or DVDs.

Rick

I've got a question about using car speakers with a PC amp unit.

I'm not an audio expert, but I did get lucky with my first cab, as I simply took a cheap PC speaker set (Creative Inspire 2.1), and just spliced my existing 6" arcade speakers in as the satellite speakers. Everything worked great.

This time, I thought I'd go the same route, but instead bought some car speakers since I didn't have any original arcade speakers. I spliced the car speakers in, and got nothing this time except for some buzzing.

I suspect it's just a power level issue, as the Creative amp is only rated for 6 watts RMS per satellite, and the car speakers are 35 watts (160 watts max). Pretty big difference. Both the car and PC speakers were 4 ohms impedence, so I've got a match there. I've also checked the polarity for the wires.

Do I just need more "oomph" to drive the speakers? Would a car amp be a better solution, or a more powerful PC 2.1 speaker set? Any other route to take?

The goal here is to find some nice 5" speakers that would fit into the new cab. I'm not too picky on how they're driven, but it would be nice to have some sort of volume control pod (like I currently have with the Create 2.1 speakers).

Any ideas?

Kevin

[MaximRecoil]

The simple is to use a car amp to power car speakers.  You'll also just need an AT power supply to supply the 12v power to the amp.  Make a simple wiring harness from a PC harddrive/CD drive "Y" power cable and you can also use any 12v or 5v auto accessories.

The picture below shows a custom marquee with 2 Sony Xplod car speakers, a 200w car amp mounted in the middle and a 5v car alarm scanner (ala Kight Rider) mounted beneath them.  All is powered by a 300w AT PS and 1 custom wiring harness.

You'll get the best sound and loudest sound with no distortion.  Additionally, since the amp has subwoofer connections, there is a car tube subwoofer inside the cab to provide earth shaking bass.

PC power supplies = a make-do solution, not the best choice. They are not designed for the demands of a car amp with any power. Plus they only put out 12v and a typical car amp has an unregulated (or loosely regulated) power supply and if you only put in 12v you won't get much out of them. What kind of "200 watt" amp are you talking about anyway? A typical amp that claims to be "200 watts" has an interesting way of achieving that figure. First they rate it with a 14.4v input (that makes a huge difference). There are precious few car electrical systems that can supply 14.4v, much less a PC power supply. Second, this is typically a 2 ohm stereo rating or 4 ohm bridged assuming a 2 channel amp.

So what are you going to get realistically from a "200 watt" car amp with a 12v input and a 4 ohm stereo load (such as would be the case with a pair of Sony coaxials)? First you can cut the power in half for the fact that you are running it at 4 ohms instead of 2. Now it is a 100 watt amp. Cut it in half again because of the ridiculously low 12v input from the PC power supply (a typical car electrical system will supply about 13.5v) and now you have a 50 watt amp.

Also, a "tube subwoofer" could in no way be described as "earth shaking bass" in any application. And...is this subwoofer powered or is it drawing off that "200 watt" amp?

Now, an awesome sound system could certainly be set up in (or around) an arcade cab using car audio equipment but a high quality 200 ampere (big $$$) inverter that will supply 14.4v would be a minimum IMO. Then you would need a 1000 watt amp for your mids and highs (best way would be a pair of 500w x 1 @ 4 ohms amps) and then at least a 1000 watt amp for your sub(s). To really make bass in a large area such as a room in a house (which doesn't have the bass reinforcement qualities of a small area like a car) you would want at least a high quality 15" driver.

I wouldn't have brought all of this up but your terminology to describe that setup ("You'll get the best sound and loudest sound with no distortion...there is a car tube subwoofer inside the cab to provide earth shaking bass.") is not really accurate.

[PileOfMonkeyCrap]

I've used AT power supplies to power stereo systems in several cabs.  The main reason is the price :  free - $20.  I'm sure there are "better" solutions, but my ears can't tell the difference.  As long as there's no liss, distortion or muddy bass, then I'm good to go.  Besides, an original arcade game usually had a rinky dinky speaker for the sound...so my setup blows that away for game playing.  Of course the amp states "200w" but we all know those are exaggerated to seem more powerful than the next amp.  Just a consumer marketing ploy.  

A tube subwoofer certainly is awesome in an arcade cabinet and for music, videos and DVDs.  As with any application, money can't be spent & spent & spent.  But I'm not vying for a Motor Trend award winning car stereo system, nor am I'm vying to have an audiophile's wet dream in my cabinet.

I was going for a futuristic, original and unique look and also kick ass sound.  My ears, eyes & customers tell me that I was successful.

Rick

The simple is to use a car amp to power car speakers.  You'll also just need an AT power supply to supply the 12v power to the amp.  Make a simple wiring harness from a PC harddrive/CD drive "Y" power cable and you can also use any 12v or 5v auto accessories.

The picture below shows a custom marquee with 2 Sony Xplod car speakers, a 200w car amp mounted in the middle and a 5v car alarm scanner (ala Kight Rider) mounted beneath them.  All is powered by a 300w AT PS and 1 custom wiring harness.

You'll get the best sound and loudest sound with no distortion.  Additionally, since the amp has subwoofer connections, there is a car tube subwoofer inside the cab to provide earth shaking bass.

PC power supplies = a make-do solution, not the best choice. They are not designed for the demands of a car amp with any power. Plus they only put out 12v and a typical car amp has an unregulated (or loosely regulated) power supply and if you only put in 12v you won't get much out of them. What kind of "200 watt" amp are you talking about anyway? A typical amp that claims to be "200 watts" has an interesting way of achieving that figure. First they rate it with a 14.4v input (that makes a huge difference). There are precious few car electrical systems that can supply 14.4v, much less a PC power supply. Second, this is typically a 2 ohm stereo rating or 4 ohm bridged assuming a 2 channel amp.

So what are you going to get realistically from a "200 watt" car amp with a 12v input and a 4 ohm stereo load (such as would be the case with a pair of Sony coaxials)? First you can cut the power in half for the fact that you are running it at 4 ohms instead of 2. Now it is a 100 watt amp. Cut it in half again because of the ridiculously low 12v input from the PC power supply (a typical car electrical system will supply about 13.5v) and now you have a 50 watt amp.

Also, a "tube subwoofer" could in no way be described as "earth shaking bass" in any application. And...is this subwoofer powered or is it drawing off that "200 watt" amp?

Now, an awesome sound system could certainly be set up in (or around) an arcade cab using car audio equipment but a high quality 200 ampere (big $$$) inverter that will supply 14.4v would be a minimum IMO. Then you would need a 1000 watt amp for your mids and highs (best way would be a pair of 500w x 1 @ 4 ohms amps) and then at least a 1000 watt amp for your sub(s). To really make bass in a large area such as a room in a house (which doesn't have the bass reinforcement qualities of a small area like a car) you would want at least a high quality 15" driver.

I wouldn't have brought all of this up but your terminology to describe that setup ("You'll get the best sound and loudest sound with no distortion...there is a car tube subwoofer inside the cab to provide earth shaking bass.") is not really accurate.

[PileOfMonkeyCrap]

Sounds like you're using Sony Xplod speakers as well?  I didn't have any magnetic interference at all either, and I was using a TV.

I have the speakers backlit just from the florescent light ($12 Home Depot) that I installed.  The red cones do look very cool backlit.

Rick

SS427:


I don't have any obvious magnetic interference with the D9200 monitor, so I'm assuming I don't need cancellation magnets.

Sound is great from the car speakers I bought, and as a bonus the cones on the speakers are a translucent red plastic -- I'm already working out ways to illuminate them from behind!  

Kevin