what does ohms and db mean?

[jomari]

Originally Posted by saprano

what do you mean by cleaning? you mean the amp?

power conditioners, surpressors, and the like.

mostly to keep spikes filtered from your home theater gear.

nice on the purchases btw.

ohms is 'push' by the way. the lower the ohmage on the speaker, the 'harder' the effor the receiver has to shoot to get you your sound.

about the sensitivity, like i said,

it takes a reciever MORE increments to produce a speaker with lower sensitivity, than a speaker with a higher one...

so if speaker A has 80db, and you turn your reciever up to level 12,

you use speaker B that has 100db, youd probably only need the reciever to go up to level 8 to match the same sound the speaker A does.

its not a matter of how clean its being produced, its still sound no matter what.

cleanliness of the sound is measured in THD (total harmonic distortion)

[jomari]

Originally Posted by Pilam69

In car audio the lower the ohm rating the better the quality of the sound and the higher quality of amplifier you will need to run it. I am fairly certain the same concept applies to home audio as well (I really can't imagine why it would be different). An amp that can handle a 2-4 ohm load will be pushing significantly more wattage than an 8 ohm amplifier (which requires better components, bigger capaciters, etc.), this doesn't mean the sound is dirtier by any stretch of the imagination. GENERALLY, the better the speaker the lower the ohm load it will handle.

correct. its not just in the car industry but in general. the problem is that there are only a few manufacturers of 4ohm even 2ohm speakers out there, to cater to the large market of 'home theater enthusiast' right now. the 'audiophiles' are the ones who normally purchase these, and mostly listen to stereo material. an amp that can push 2-4-6 ohms can 'generally' push 8ohms speakers easily, thus more expensive.

what looks good on paper, doesnt necessarily mean its true.

[Colorado Blu Skies]

Originally Posted by d_rob1031

Just a heads up, don't let db make a decision for you. It takes 3db for the human ear to notice a difference in volume. In other words, if there's a tiny difference between 2, don't automatically think the higher is better, you won't notice a difference.

edit: gah, this take me back to college and circuits class. yuck.

I just finished my first circuits class... not really looking forward to the next few.

[powerSURG]

adding 3db does double your power.

[richteer]

Originally Posted by Pilam69

In car audio the lower the ohm rating the better the quality of the sound and the higher quality of amplifier you will need to run it. I am fairly certain the same concept applies to home audio as well (I really can't imagine why it would be different). An amp that can handle a 2-4 ohm load will be pushing significantly more wattage than an 8 ohm amplifier (which requires better components, bigger capaciters, etc.), this doesn't mean the sound is dirtier by any stretch of the imagination. GENERALLY, the better the speaker the lower the ohm load it will handle.

With respect, that's total hogwash!

The "ohm rating" (which is the measurement of how much resistance a given speaker presents as a load) has got absolutely nothing whatsoever to do with sound quality. There are good high impedence speakers, and crappy low impedence ones. I'll take my 8 ohm Spendor SP1/2s over some crappy 4 ohm speaker any day of the week!

It is true that a speaker that has a lower impedence is usually harder to drive than one with a higher one, because it'll require more current to drive it and crappyy amps tend to have crappy PSUs and hence can't supply the required current.

Impedence and sensitivity (the db figure the OP refered to) together give an indication of how "hard" a speaker is to drive. A speaker with a low impendence (say, 1 ohm) and low sensitivity (~80 db) would be an absolute ***** to drive. For an example of this type of speaker, look no further than the Apogee Scintilla (RIP)...

[frenchglen]

Wooooaaaah I'm all spec'd out.

[musicman1999]

Originally Posted by powerSURG

adding 3db does double your power.

No, doubling your power adds 3 DB, it is not the same. DB is a measure of volume, like a power saw is 110 DB measured with a sound meter three feet away.


bill

[musicman1999]

When a speaker is given a DB rating, it means that 1 watt of power measured 1 meter from the speaker will drive that speaker to the specified DB rating.


bill

[NJMetsFan]

Originally Posted by Pilam69

In car audio the lower the ohm rating the better the quality of the sound and the higher quality of amplifier you will need to run it. I am fairly certain the same concept applies to home audio as well (I really can't imagine why it would be different). An amp that can handle a 2-4 ohm load will be pushing significantly more wattage than an 8 ohm amplifier (which requires better components, bigger capaciters, etc.), this doesn't mean the sound is dirtier by any stretch of the imagination. GENERALLY, the better the speaker the lower the ohm load it will handle.

Lower ohm rating doesn't mean better. The less the resistance is, the more crap that will go to your speakers. Take this example.

You have an amp that does 400w @ 4 ohms but you can bridge it to give you 800w @ 2 ohms. Your power is increased but your signal quality will go down. If that same amp can handle a 1 ohm load, it will give you even more power but that power is dirty. Which mean that your sound quality will go down. It might be very loud, but it won't have the same sound quality.

I would take a 800w @ 4 ohm amp over a 800w@ 2 ohm amp, because your sound will be better. It will cost a lot more to buy a amp that puts out a lot of power at 4 ohms than one that puts out the same power at 2 ohms.

[NJMetsFan]

http://www.surrealmirage.com/subaru/tip.html#thd

I just found this site...and I quouted some info.

THD - Total Harmonic Distortion is a good number to help determining a good amplifier from the cheapos. For starters, a THD of 0.1% or greater is audible to the human ear, anything less you won't notice. Head units usually have a very low THD. THD usually comes into play in amplifiers, especially when running at a lower ohm rating.

Power Ratings at Different Ohm Loads - An Ohm is a measurement of resistance in wiring. Every type of wire has resistance, if you have no resistance you have a short, and lots of sparks. Manipulating Ohm loads with speakers and amplifiers can be very beneficial. When you decrease the ohm load by half, you will increase power by a factor of two. Lets say you have an amplifier that puts out 50 watts/channel at a 4 W load. If you have a 4 W speaker, you get 50 watts. If you have a 2 W speaker you will get 100 watts, but there is one caution. When you decrease ohms, you increase THD.

[saprano]

I learned so much today

[saprano]

Originally Posted by NJMetsFan

http://www.surrealmirage.com/subaru/tip.html#thd

I just found this site...and I quouted some info.

some more learning, everything is starting to make sense now.

[NJMetsFan]

Originally Posted by saprano

some more learning, everything is starting to make sense now.

Glad to help.

[Pilam69]

Originally Posted by richteer

With respect, that's total hogwash!

The "ohm rating" (which is the measurement of how much resistance a given speaker presents as a load) has got absolutely nothing whatsoever to do with sound quality. There are good high impedence speakers, and crappy low impedence ones. I'll take my 8 ohm Spendor SP1/2s over some crappy 4 ohm speaker any day of the week!

It is true that a speaker that has a lower impedence is usually harder to drive than one with a higher one, because it'll require more current to drive it and crappyy amps tend to have crappy PSUs and hence can't supply the required current.

Impedence and sensitivity (the db figure the OP refered to) together give an indication of how "hard" a speaker is to drive. A speaker with a low impendence (say, 1 ohm) and low sensitivity (~80 db) would be an absolute ***** to drive. For an example of this type of speaker, look no further than the Apogee Scintilla (RIP)...

With respect..........first of all, I said GENERALLY. Secondly, the better speaker manufacturers and more expensive speakers CAN handle a lower Ohm load than less expensive speakers. You really won't find many "cheap" or "crappy" 4 Ohm speakers. Therefore, GENERALLY, the lower the Ohm rating on a speaker the higher quality the speaker is. Also, GENERALLY, to find an amp that can push a 4 Ohm speaker you will have to buy a bigger amplifier, which means bigger components which GENERALLY means higher quality.

OF COURSE this is not always true and there are great 8 Ohm speakers out there but they will GENERALLY not measure up to a 4 Ohm speaker in quality of build and sound quality. GENERALLY.

[Pilam69]

Originally Posted by NJMetsFan

Lower ohm rating doesn't mean better. The less the resistance is, the more crap that will go to your speakers. Take this example.

You have an amp that does 400w @ 4 ohms but you can bridge it to give you 800w @ 2 ohms. Your power is increased but your signal quality will go down. If that same amp can handle a 1 ohm load, it will give you even more power but that power is dirty. Which mean that your sound quality will go down. It might be very loud, but it won't have the same sound quality.

I would take a 800w @ 4 ohm amp over a 800w@ 2 ohm amp, because your sound will be better. It will cost a lot more to buy a amp that puts out a lot of power at 4 ohms than one that puts out the same power at 2 ohms.

Exactly right. Ohms are just ONE factor to consider when looking at audio quality. Why have a 2 Ohm speaker that blares a bunch of noise along with the audio signal?

Again, I'm not trying to say that lower is absolutely better, just that it can be a factor that a novice can use as an indicator................GENERALLY.

[MacHaggis]

Speaker impedance can be described as follows:

Say a speaker system has an impedance of 8 ohms. That is the resistance (or damping effect) encountered by the electrical stream generated by the amplifier through the electronic and physical components of a speaker (crossover electronics and the physical driver within the speaker).

As the resistance drops in the system, the flow of electrons through the system will increase.

When the resistance approaches zero ohms, the flow of electrons becomes so great that heat build up occurs causing the circuit to fail. That would be a short-circuit.

So, at 4 ohms impedance, the current flow would be greater, and the power supplies for some amplifiers will not efficiently handle that... this may be more of a problem during loud volume playback for extended periods of time.

Many modern amplifier circuits have built-in safety circuits that will cut the power output when an overheat condition is detected.

Bogdan

[d_rob1031]

Originally Posted by MouseRider

Totally, it isn't about "loud" or "raw power", it's about refinement and the ability to control the "loud" and the "power".

Ask any electrical engineer like d_rob

Honestly, I would shoot myself if I was an electrical engineer, my major just required 1 circuits class /shudders again

[d_rob1031]

Originally Posted by Colorado Blu Skies

I just finished my first circuits class... not really looking forward to the next few.

hah, enjoy that 2nd one, I never had to take it.

[reider]

Originally Posted by Pilam69

With respect..........first of all, I said GENERALLY. Secondly, the better speaker manufacturers and more expensive speakers CAN handle a lower Ohm load than less expensive speakers. You really won't find many "cheap" or "crappy" 4 Ohm speakers. Therefore, GENERALLY, the lower the Ohm rating on a speaker the higher quality the speaker is. Also, GENERALLY, to find an amp that can push a 4 Ohm speaker you will have to buy a bigger amplifier, which means bigger components which GENERALLY means higher quality.

OF COURSE this is not always true and there are great 8 Ohm speakers out there but they will GENERALLY not measure up to a 4 Ohm speaker in quality of build and sound quality. GENERALLY.

With respect.... I have to agree with richteer's rebuttal of you post, and to add that you GENERALLY don't understand what are you talking about. Sorry.

[d_rob1031]

Originally Posted by NJMetsFan

http://www.surrealmirage.com/subaru/tip.html#thd

I just found this site...and I quouted some info.

I'm really glad someone brought THD up. To me, it is the most important rating on any amp.

Example: If you have 1000watts @ 10% THD, which is what most HTIB run at, you lose a lot of that 1000watts (which is peak, mind you, something else I'll touch on) that is used up by the amp.

Take that same 1000watts @ < 0.05% THD, which is what a lot of amps run at, better ones run even lower, you're going to break every window in the house. Which is why they don't run at 1000 watts

I just looked up the Onkyo 805 and it runs at 130watts per channel at 0.05% THD. If you took that same 130watts per channel at 10% THD you would have horrendous sound with crackling and loss.

The HTIB also are rated at peak power whereas real receivers are rated at RMS (root meat square). RMS is the wattage at which it's able to consistently do over a stated period of time. Peak power is the max it will do before it blows its self up, in other words, it never makes its peak power.

Hope this clears up why HTIB's usually suck (there are decent ones out there) and explains THD and how it's used.