Have any of you ever heard this? I found this quote on another site.

"You have to be careful with new speakers. 99% of new door speakers are 4ohm and the amps run at 3 or 4 ohms. But they are wired in parallel so that would drop your door speakers to 2 ohms and the amps will eventually cut out because of being over worked."

The implication here is that stock speakers in my 2012 are 2 ohm not 4. For any of you who have replaced the speakers with aftermarket 4 ohm speakers do you have to turn the volume up higher than before? That would indicate the above quote is accurate.

Thanks!

 

While I don't have any hard evidence that this is true it sounds like BS to me. Im pretty sure the stock speakers in the Mustang are 4 ohm, not 2 ohm, I will test my stock speakers with my multimeter later to confirm this. And more than likely if you have replaced your stock speakers and have to turn the volume up more to achieve the same level of volume as your stock speakers it was due to the sensitivity ratings of the speakers rather than the ohms. The higher the sensitivity rating, the less wattage it takes to achieve that volume.

Wikipedia qoute

"For the first example, a speaker 3 dB more sensitive than another produces double the sound power (or be 3 dB louder) for the same power input. Thus, a 100 W driver ("A") rated at 92 dB for 1 W @ 1 m sensitivity puts out twice as much acoustic power as a 200 W driver ("B") rated at 89 dB for 1 W @ 1 m when both are driven with 100 W of input power. In this particular example, when driven at 100 W, speaker A produces the same SPL, or loudness as speaker B would produce with 200 W input. Thus, a 3 dB increase in sensitivity of the speaker means that it needs half the amplifier power to achieve a given SPL. This translates into a smaller, less complex power amplifier—and often, to reduced overall system cost."

In some cases it also means that the accuracy suffers so sound quality will also suffer. It all depends on the brand.

But where you heard that using a higher resistance, lower ohm speaker will cause the amplifier to work more is true. If the amp is not specifically listed as being stable at 2 ohms then it will overheat and likely damage the amp. Higher resistence leads to higher heat. Some amplifiers are built for that though and will work fine. Others (cheaper), not so much!

Hope this helps!

 

Amps run at 3-4 ohms? Sounds like someone needs to understand basic electrical principals.

 

the amps themselves don't run at ohms, ohms is resistance, the less resistance, more power sent through, more work being done by amp. Most speakers are 4 ohm speakers, allot of guys run subs in parallel and bridge the channels, effectively sending more power to speakers. Yes it is harder on the amp.

Now that the lesson is over, Are you talking sub woofers or door speakers? Door speakers really wont bother the amp. Sub woofers will push the amp allot more and this is where you would run into problems with the amp overheating. Once overheating starts, you will risk blowing the amp, or it will reach its thermal cuttoff and turn off. On its way up to temp, you will get distortion in the sound. Basically, keep good ventilation and you prolly wont see a problem unless you are running 1000 watt amps.

Resume: Electronic Tech., Studying Electronic Engineer.

 

I think what the person meant was that the amps are stable at 3 to 4 ohms. But yes, learning more about how these audio components work and basic electrical principles will help as well.

 

the only weird rating are the door subs which are 1.2 ohms

 

which ford has prolly tested that the Deck/amp can be stable at running the speakers at 1.2 ohms. Is this from a shaker system or not?

 

Great answer RobDis, thanks.

 

Thanks all. So do I need to evaluate the sensitivity rating on the speakers as much as the ohm number? I am wanting to upgrade to probably Infinitty Kappas.

 

The only time you need to worry about Ohm's is with Subwoofers. The stability of the amplifier and the Ohm rating of the subs, dual or single voice coils, and wattage reccomendations will all be necessary. Most amplifier manufacturers have amps and subs that "match" meaning that the power rating of the amps match the subs. This doesn't mean you have to use the same brands but mixing can be a pain finding the right combination. I currently run an Alpine Sub with a Kicker amplifier. The sub is dual 4 ohm voice coils and rated at handing up to 400 watts. The Kicker amplifier is a ZX400.1 monoblock which is stable at 2 ohms (dual 4 ohm voice coils wired in parallel is 2 ohms). I won't get into a debate about why I choose that combination, mainly it was because I bought both from an Ebay store that I found while in Illinois and got the sub for $50 and the Amp for $100 both still in the boxes and still in plastic. They were some kind of Best Buy liquidator. If anyone wants the Ebay Store name just let me know!

Most all interior speakers, coaxials, or components are going to be 4 ohms. Even component sets, also called separates where the woofer ans tweeter are separate are still only 4 ohms if connected to the supplied passive crossover. Now if you are connecting 2 separate sets of speakers in parallel to a power source then you will be walking on possible shakey ground. I have done this and it works, but when you are really pushing the stereo hard it will overheat most 2 channel or 4 channel amps. Right now I am running a 4 channel amp and each channel has one speaker at 4 ohms resistence. Most stereo (not mono) amplfiers are stable at 2 ohms per channel stereo, and 4 ohms mono/bridged. Mono/bridged means you are using a stereo amplifier to push only one speaker. Usually done in a 1 subwoofer setup. Nowadays though most sub amplifiers are monoblock meaning they only have 1 channel. And some are stable down to as low as .5 ohms, though 1 or 2 ohms stable is the norm. I have an older Kicker amp that if you only have one of the 2 channels connected the amp will sense this and will not even turn on. It also senses if you have the ohms wrong and will not turn on then either. I know because I have tried, I hooked up a 2 ohm load to it in a mono configuration and got nothing. But as soon as I put a 4 ohm load to it it started playing no problem. That's a safety feature in that amplifier and pretty swift if you ask me.

 

RobDis. Based upon your comment above regarding sensitivity, and the fact that the Infinity Kappas I am looking at have a 94 dB sensitivity rating verses the 88 dB rating of the Pioneer TS-D6802R that so many people of this site has used, would the Infinity's be closer to factory volume settings?

 

This is precisely why I chose the Infinity's when I first replaced the door speakers in the mustang. But this doesn't necessarily make the Infinity's better than the pioneers. It just means that if supplied with the exact same power source they will be louder. Loudness and sound quality aren't the same obviously. The only way to really decide is to hear the 2 choices side by side. I like the Pioneers and the Infinity's equally but wanted as much volume as possible due to the sub I added in the trunk. Now I am running a set of Polk Dxi 6500 components I got from Best Buy for about the same price you can get the Infinity Kappas off Crutchfield. There was a world of difference in the Polks and the Infinity's in quality and they have a 92db sensitivity rating. I also have an amplifier on the interior speakers as well.

 

In case this might apply to someone. I wired the stock door sub in series. It comes with dual voice coils, wired in series you can run it easily off one side of an additional stereo amp allowing you more power and independent volume control over the door subs. I wanted a fairly light simple system without a trunk mounted sub so while not cheap it works pretty good a lot better than the base no sub system my car came with. The amp is in the trunk fed by the rear speaker wires. The amp then feeds the subs mounted in the doors. The sub volume can be controlled with the fader built into the stock head unit.

 

RobDis, how did you mount the components since they seem to require three separate mountings? And you believe the Polks are superior to the Infinity's? Is that just because it is a component? Thanks

 

This is an excellent idea! I removed my subs and have them hooked up to a small amplifier in a setup inside my house if you can believe it, running off a computer power supply! I did the same thing, wired them in a series to a stereo amplifier.

 

I used a hole saw and cut a hole in the door panel for the tweeters. For the 6.5 I used an adapter plate.

http://www.metraonline.com/part/Ford_Dash_kit_82-5600

I mounted the crossover in the enclosure for the door subs since I removed them anyways. I would have used 3m tape to secure the crossover inside the door where the speaker are mounted but I am also using a foam baffle behind the speaker to eliminate vibrations inside the door.

I do believe the Polk Audios are better than the Infinitys because I can tell a noticeable difference in the sound now that they are installed and it may very well be because they are components. But the tweeter for the polks is much larger than the tweeter in the Infintys also.

 

RobDis,
Thanks for clarifying. I pretty much want a plug and play, and based on your earlier comments, I think the Infinity's are my best choice. I appreciate all your commentary and advice.

 

Your very welcome.