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Watts, Ohms, Oh My!
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| Bryant |
| I really need help understanding about watts and ohms. What are ohms and how do they differ with watts? I notice that the fewer ohms there are, the more watts you will get, but why is this? The reason I ask is because I am awaiting my crown ce-1000 amp and having trouble on deciding on some club speakers. I was thinking of getting a Gemsound 2155, but notice that at 800 watts its Impedance ohms is at 8. While comparing that to the crown amp, its 8 ohms is rated at 275 watts. So in an essence, there is some wasted (or lost) wattage there. How can I get more out of my amp? Please educate me! :D Thanks! |
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| Kid Lax |
ohms = measurment of resistance
watts = measurment of power ( power = current * voltage = current^2 * resistance = voltage^2/resistance )
im not really sure how this all comes to play in terms of sound, ive only studied this stuff in an electrical mindset
but just keep in mind that high wattage != better speakers
i don't know a lot about speakers though so im not much of a help :p
all i know is that there's the frequencey max/min's and some db (i think) measurement that is taken a meter away from the speakers that have ot be considered also
i dunno ill leave this one to the experts :p |
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| HyPeRSoNiC |
| quote: | Originally posted by Bryant
I really need help understanding about watts and ohms. What are ohms and how do they differ with watts? I notice that the fewer ohms there are, the more watts you will get, but why is this? The reason I ask is because I am awaiting my crown ce-1000 amp and having trouble on deciding on some club speakers. I was thinking of getting a Gemsound 2155, but notice that at 800 watts its Impedance ohms is at 8. While comparing that to the crown amp, its 8 ohms is rated at 275 watts. So in an essence, there is some wasted (or lost) wattage there. How can I get more out of my amp? Please educate me! :D Thanks! |
actually, you can't get more out of the amp...... unless you get speakers with 4 ohms....
I suggest you get speakers that match your amp....
for example:
your amp is 275W at 8 ohms? then get speakers that their impendance is 8 ohms and they are 275W...... :)
another option os that you get speakers that are more powerfull than your amp.... that way there won't be a chance they'll burn....
I have an amp that it's power is 350W for each side at 8 ohms.... and my speakers are 8 ohms, 500W each.....
anyway, you don't need 800W.... it's just a waste of money is you have a 275W amp.... (I'm talking about 8 ohms)... my suggestion - get speakers that are about 350W, 8 ohms..... |
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| Dj Flesch |
As stated before, you can think of Watts as the amount of sound energy sent down the wire from your amp to your speakers. The resistance (measured in ohms, greek letter omega) is the amount of retardation of movement of that sound energy moving through your system. The more resistance, the more heat that is produced and vise versa. One important thing to get out of all of this isn't that there is a certain amount of wattage that you can get out of a 4ohm or 8ohm speaker, it's that it requires more power to get an 8ohm speaker up to let's say 120dB than it will take a 4ohm speaker. This is because there is more resistance for the signal to overcome in the 8ohm system over the 4ohm system--given the same path length.
By path length I mean the total length that the signal has to travel, including the length of speaker wires. Given that, this is why they tend to use 4ohm systems in clubs because the distance is much greater in a club over your home system.
So what does this all mean in practical terms? Nothing much really unless you plan on setting up a club's sound system. Just know that for your home system can be either 4 or 8ohm, and depending on your amp, possible both. Here is the important part, you can't attach 4Ohm speakers to a 8Ohm amp or you will blow them out. This is becaues your amp is expecting the signal to degrade at twice the rate it actually is, and so your 4ohm speakers will end up getting twice the amount of power then it can potentially handle. If you have a 4ohm amp with 8ohm speakers, then you will only be able to use half of the power available to your speakers (assuming the wattage on your amp and speakers are both the same in each case). Either way, stick with one or another unless your amp says that it has autoswitching. Your owners manual should state this pretty clearly.
So overall, it doesn't matter if you get a 4 or 8ohm system because you'll go deaf pretty quickly if you blast more than 150watts of power in a 12x12 room. Think of it this way, most good factory stereo systems are 90Watts-120Watts of power--and I mean good ones like Harmon-Kardon, Bose etc not Kia brand. Your ears would be ringing for hours and hours if you listened to those systems on max volume for more than 15-20 minutes. You can learn more about the hearing process here. and if you want to learn more about amps, volts and ohm etc then follow the link below:
http://science.howstuffworks.com/question501.htm |
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| Bryant |
| So your saying that the length of the wire connected to your speaker from the amp have a vital role and the greater the length of the wire, the less ohm you would need. And in the case of a 8ohm speaker, is it wise to use a long wire? I plan on being a mobile DJ (nothing too big), so I want to make sure I got this right. Thanks! |
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| The Greener |
I haven't read this thread much but I have one rule of thumb when buying Power Amplifiers
Buy American!!
Some of the best, powerful, forgiving, insane SPL Amplifiers are made in the good ole U S of A. Between the 1970's and to the mid 1990's is the time period I look for.
I would 9 times outta 10 buy somthing from this era. They used brute transformers and high current mosFET's capable of scary power levels at nightmare low impedances. Todays amps are based on that old technology along with new technology that somtimes misses the point.
Look at my review prev.
"I have had this amp for 8 years now and it has had 0 problems. I have abused it "at least I thought it was abuse" and it laughed and said is that all you got? have had 1 ohm loads on it rarely 2 ohms regularly and 4 ohms when I used it for P.A. running subs at obscene spl's. I melted 2 brand new Crate 700w x 2 amps running mids and highs trying to keep up with it!!! (That was something to see sparks flew 2 feet out of the facs side vents!) Then I brought it home and put it back in my home system and it still sounds better than my h/k or my old dynaco. This beast cannot be beaten for 4 times the price you can find them for.... 100% satisfaction is not enough!!! |
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| Dj Flesch |
| quote: | Originally posted by Bryant
So your saying that the length of the wire connected to your speaker from the amp have a vital role and the greater the length of the wire, the less ohm you would need. And in the case of a 8ohm speaker, is it wise to use a long wire? I plan on being a mobile DJ (nothing too big), so I want to make sure I got this right. Thanks! |
Okay, well, first off, I wouldn't say that the length of wire has a "vital" role, but in general you want the shortest possible connection from your reciever/amp to your speakers. Not only that, but you want each wire to be exactly the same length too. This way the signal gets to each speaker at the same time (so your phasing will be correct) and it will have retained the maximal amount of power possible. I think that you have the concept of resistance, measured in Ohms confused. Resistance is a bad thing because it reduces the power of your original signal sent from you amp to you speaker. When this happens, you get a weaker signal to your speakers and you never end up being able to use your system to its fullest potential.
As I said in my last message, 8Ohm systems are fine for home, 4Ohm systems are basically used in clubs because the wire has to be longer to get to where the speakers are. (Ie a club is going to have speakers further from the amp than you would have them at home.) Because you have less resistance in your speaker this means that you need less power to drive your speaker. If you had an 8Ohm system in a club, then your volume levels would never get as loud compared to a 4Ohm system of the same wattage etc etc. Now don't get all panicy about this ;) Honestly, this isn't really that big of a deal, and again, like I said in my last post, if this is for home, then you will never be using most of the power that your amp/speakers are capable of delivering. I have 200Watt Pioneer speakers (12" woofers) and I don't ever turn the volume up anywhere near to the max. Because of the size of my room (about 15x20, so a decent sized room) I have no need to have more volume or power than those speakers are capable of delivering at 50% volume. I'd go deaf and the neighbors would call the police on me if I turned my system up that high! ;)
Now don't take that to mean that you only need a 50W system or something. You need a certain amount of power just to drive the speakers, and for a room of my size (15x20 feet), 200W is perfectly fine. I wouldn't suggest going much below 100 Watts though. But I'll have more on wattage terminology in a minute. Another important point is that the type of wire that you use is important too. You don't want to use cheap 20 gauge wire to power your 200W speakers. Think of it like this: if a 20 gauge wire is like a 14.4k modem, then 4 Gauge is like being on a T3 broadband connection. It's like a garden hose compared to a fire hose. The larger the wire, the more signal you can push through it without pushing the limits. Lamp cord is fine too if you are on a tight budget. You don't need platinum or gold plated everything unless you can afford it or are an audiophile. Good speaker wire is freakin expensive! You'll easilly spend $30-$50 for 50 feet of wire or less...that is a lot just for wire! And that doesn't include any plugs to cap the ends (but most speakers do require that you cap the wire). You can even spend up to $300 for a 10 foot pair of wires! If you want to learn about the standard for speaker wires, then go
here to learn about it. Monster cable is by far the best type of audiophile wire out there, and the price dictates that.
So anyway, on to my Speaker terminology. You'll find two types of Wattage: Peak, which is of course the most wattage you get at one single time; and you'll also come across RMS (which means Root Mean Square, and in layman's terms mean average wattage). Using either one as a basis for compairison is fine, just make sure that you are comparing peak to peak or RMS to RMS and not any other way. RMS will have lower overall numbers but will give you a better metric to measure the average speaker performance by. Another metric to use is the SPL (sound pressure level) which is a number given in dB which basically tell you how loud the speaker gets. The higher the number the louder, but remember that the decible scale is a logrithmic scale and for every 2-3dB increase, the sound is twice as loud! I'd look for something in the 100-110dB SPL range, leaning toward the mid to upper end of the range.
There is also Wattage and wattage per channel (WPC). You're speakers will show wattage, meaning how much they can output each. Your amp will have both total wattage and watts per channel. Watts per channel time the number of channels will give you total watts. Sure there are plenty of club amps that are like 1500W etc, but most of them will have a much lower WPC rating, and the main thing to look for here is that you match up your amp's WPC with your speaker's RMS wattage or peak wattage. It doesn't matter if your speaker can put out 400W if you amp is only capable of delivering 100W to your speakers. And don't get speakers that are 100W if you amp is going to try to deliver 300W to them. You'll blow your speakers out at high volumes (though at lower volumes, you'llbe fine). My main point is that you match up the components of you system to eachother.
Anyway, I hope this massive post has helped you understand more about basic speaker and amp terminology and will lead you to a more informed desicion. Good luck and let me know if there is any other questions that you have that I may be able to answer!
EDIT: Also, as I tell everyone that want equipment advise, go and listen to it yourself! Go to best buy and listen to some of their systems. Look at the power ratings and figure out what you want from there. Don't just blindly buy a speaker on the net because it's a "good deal". Know the brand you are buying, specifically, know what the product sounds like! Don't ignore other important specs like frequency range too! |
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| fr0st |
| quote: | Originally posted by Kid Lax
ohms = measurment of resistance
watts = measurment of power ( power = current * voltage = current^2 * resistance = voltage^2/resistance )
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lol I havent seen that since physics class, oh the memories..... |
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| Bryant |
| Dj Flesch, thanks for your wonderful informative post! I learned a lot! Thanks again! :) |
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| Bryant |
| Actually I got one more question. Just out of curiosity, why would you get more wattage when it is bridged? |
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| P`zazz |
this thread is very informative :) I actually sat down and read all of it
btw does anyone have pics of some different types of wire? I really want to know of better quality wiring |
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| Dj Flesch |
| quote: | Originally posted by P`zazz
this thread is very informative :) I actually sat down and read all of it
btw does anyone have pics of some different types of wire? I really want to know of better quality wiring |
If you follow my link for monstercable (www.monstercable.com ) then you can learn a bunch about the best wire out there...or at least the industry standard.
Bryant, I'm not sure what you mean by your question. What do you mean by bridged and What is being bridged?
And another thing to add to my posts is that speakers now-a-days have changed due to dolby surround etc. Most main speakers for a home entertainment system won't be as high Wattage as they used to be for one main reason--subwoofers are now a standard part of any home entertainment system and it is the sub that gives you the main bass and not the main speakers. So you'll want to look at speakers that are still capable of delivering good bass power in a single pair of speakers. |
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