Hello all. Have a stupid question. When you look at all the speakers at there and all say they are the best one will notice that there are 4 , 6, 8 ohm speakers. Mainly 8 ohm is the most common I will say. Why do they offer speakers in the other ohms as they will suck more power from your amp or make it run hotter. What are the benefits of the other ohm speakers? The amp runs 8 ohms normally. Thanks for answering a stupid question.
Speaker ohms.
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DesertRatt
All Bark, No Bite!
The "ohms" in speaker ratings represent an average IMPEDANCE, not a simple RESISTANCE. When you say "suck more POWER" that's not necessarily true. POWER is volts x amps. Therefore 4 volts x 2 amps, is the same POWER as 2 volts x 4 amps. Ergo, you can't automatically assume that a 4-ohm speaker sucks more power than an 8-ohm speaker.
Why are there 4 ohm speakers and 8 ohm speakers? The designer may have PREFERRED drivers and crossover design that simply lead to that value. Almost all modern amps can handle 4 ohms just fine.
Yes, power = volts x current. Another way of putting it is power equals voltage squared divided by resistance. Amplifiers are voltage sources, so they can deliver more power into 4 ohms than they can into 8 ohms. In fact, that's the reason why some speakers are 4 ohms - you can get more power from the amplifier than you could with 8 ohm speakers. The downside is that the amplifier is more likely to be destroyed by a 4 ohm load than an 8 ohm load. Amplifiers also tend to have less distortion into 8 ohms than 4 ohms.
shelly_d
Not An Audiophool
It is just a design choice by the speaker designer. Typically, the design process will start with a set of goals and in trying to meet those, other aspects of the design may change. This could lead to a change in impedance. It is not uncommon to see drivers of different impedances mixed in the same speaker as a result. If confused, just use the impedance rating of the speakers as a go/no go decision. I.e. if you are looking at a 4 ohm speaker but your amp is recommended for 8 ohms and above (there are some out there like this) look to a different speaker. If the amp is OK with that impedance speaker, move on to whether you like it or not. Although a 4 ohm speaker puts more load (i.e. draws more current) on the amp, as long as you don't get loud enough to cause distortion (i.e. clipping) there should be no technical issue. Just enjoy what you have and leave the design issues to the designers.
Shelly_D
Shelly_D
Thanks all. When looking at speakers one sees the different ones. I just always heard that a 4 ohm speaker will heat up the amp more than regular 8 ohm. It seems this is just my opinion only while I poke around I see the 4 ohm on sale more. Probably just me.. thanks for the replies all. appreciated.
That's where it gets complicated. The impedance rating is more or less an eyeball average of the impedance picture. Actually, the speakers impedance is constantly changing as the drivers move, frequency changes, crossovers cross over, and ports vent. Some speakers change dramatically, others not so much.
The purpose of the rating is to help you choose amplification to drive your speakers.
Sandman1221
Super Member
I have 4 ohm speakers, and the top of the metal case for the amp does get hot, but with a 5" pancake fan running on low above the 4 power supply capacitors, the top of the metal case of my amp stays at room temperature.
It isn't just your opinion, it's a fact that 4 ohms will dissipate more power than 8 ohms for a given position of the volume control. However, for a given SPL, you will be running the amp's volume control at a lower position (all else being equal, which it never is).
twiiii
Lunatic Member
Go to the Stereophile website and pull up speaker tests and look for measurements. Look at the impedance curves on a bunch of speakers. Some are reasonable and some horrendous. In the old days a speaker impedance was usually measured at the dip in the woofer impedance just above its impedance peak. If a speaker is ported or horn loaded the woofer may have two peaks with a valley in between which is usually the resonant frequency of the port, horn enclosure, but its still the dip just above the peaks in the woofer curve that determines the speakers impedance. Normally tweeters and mid range speakers are more efficient than a woofer so resistance is added to lower the output and increasing the impedance so that area of the frequency response was not considered in evaluating the speaker impedance. Today its a different story with much more advanced designs. Some speker companies who say their average impedance is 4 ohms may approach 2 ohms over quite a range in the bass and lower midrange. Panel speakers can some times drop close to an ohm at very low frequencies and very high frequencies. That why the best amps today will operate down to 2 ohms with no sweat. Mcintosh even puts 2 ohm taps on some of their amplifiers to handle these speakers. But ideally the amp you choose should be able to supply rated power at say 8 ohms and if a 2 ohm dip comes along be able to supply the required current when the impedances drops. One the answers mentions "modern and most" in his answer. Those two words are why a lot of folks should stick with equipment no older than coming from the 2000's and even then you are taking a chance with unfamiliar speakers that can really cause issues and a lot of heart ache for the owner and his less than adequate choice in electronics.
Impedance is a tricky subject. There is the main part, the resistance and then the imaginary part or the phase angle between the current and voltage. If the phase angle get to large current requirements can go right through the roof even if the resistant part of the impedance curve is really of no concern. Thats another chance for amps to have heart attacks. I don't know why designers do these stunts with their designs and leave us to deal with the fall out, but they do. A complex impedance can really give a tube amp fits. Depending on the quality of the output trans former and tube circuits tube amps frequency response may vary over +/- 6 db quite easily and why tube amp owners are always switching amps to find the one tube amp that complements their speakers issues. Direct couple SS amps of high quality are not affected in most cases. Average SS consumer amps and integrated amps and AVR's can have serious issues. B&K HT AVR's really suffered with low impedances and extreme phase angles. So did early Yamaha and Kenwood among others. ARC tube amps had real issues early on, too. Even Mcintosh and Marantz had models that suffered with some hard to drive speakers. Others such as Accuphase, Bryston and Krell not so much. At least they weren't in our shop for repairs all the time like the middle of the road amps from well know brands such as Yamaha, B&O, Sony, Kenwood, AIwa, Mitsubishi, and Harmon Kardon Products in the 70's thru early 2000's. Yamaha commercial, Urei Commercial, QSC, Meyer, and a few other amps worked well as consumer amps because they were designed to handle abuse. Some Crown performed well others didn't. Carver amps , Phase Linear, Bose , and Tandberg amps all had issues. With out the service networks we had in the past you really have to pay attention where you spend your monies today. Other wise you are apt to get burnt in the pocket book with very little recourse.
Impedance is a tricky subject. There is the main part, the resistance and then the imaginary part or the phase angle between the current and voltage. If the phase angle get to large current requirements can go right through the roof even if the resistant part of the impedance curve is really of no concern. Thats another chance for amps to have heart attacks. I don't know why designers do these stunts with their designs and leave us to deal with the fall out, but they do. A complex impedance can really give a tube amp fits. Depending on the quality of the output trans former and tube circuits tube amps frequency response may vary over +/- 6 db quite easily and why tube amp owners are always switching amps to find the one tube amp that complements their speakers issues. Direct couple SS amps of high quality are not affected in most cases. Average SS consumer amps and integrated amps and AVR's can have serious issues. B&K HT AVR's really suffered with low impedances and extreme phase angles. So did early Yamaha and Kenwood among others. ARC tube amps had real issues early on, too. Even Mcintosh and Marantz had models that suffered with some hard to drive speakers. Others such as Accuphase, Bryston and Krell not so much. At least they weren't in our shop for repairs all the time like the middle of the road amps from well know brands such as Yamaha, B&O, Sony, Kenwood, AIwa, Mitsubishi, and Harmon Kardon Products in the 70's thru early 2000's. Yamaha commercial, Urei Commercial, QSC, Meyer, and a few other amps worked well as consumer amps because they were designed to handle abuse. Some Crown performed well others didn't. Carver amps , Phase Linear, Bose , and Tandberg amps all had issues. With out the service networks we had in the past you really have to pay attention where you spend your monies today. Other wise you are apt to get burnt in the pocket book with very little recourse.
twiiii
Lunatic Member
My first 3 setw of speakers were 16 ohm. Stephens with Oxforf super tweeter, Altec Coronado with a 601 D as I remember and an Altec 838 Carmel using two 8 ohm 414's in series and starting with a 16 ohm 806 driver, that I upgraded to an 802- 16D to get better response above 8 KHZ. with 3 db more efficiency so I could turn down the crossover a bit to protect the diaphragm that was only rated at 10 watts RMS. But with the crossover turned down over 8 or 9 db I didn't worry about blowing a diaphragms as my Mcintosh MA 230 only put out about 38 watts before running out of steam, which was more than enough for me. As I remember the speakers efficiency was around 100 db 4 ft 1 watt 16 ohms. Later on Altec changed the speaker to 8 ohms using two 16 ohm woofers in parallel and changing the HF diaphragm to 8 ohms and the crossover also. I was thinking about doing that when I heard a pair of Bozak Symphony Speakers with the tweeter line array and sold my Altecs. They both reached as low and as high, but the 8 inch midrange and the tweeter line array got rid of that honky horn sound the Altec speakers had. I bought Grands instead of Klipschorns for the same reason. I though about buying Mac ML-4s but the sound wasn't right with the tweeters and mids being to close to the floor. Stacked pairs of ML-2's didn't sound right either.
I think a lot of confusion is due to advertising..
Speakers that are capable of 3000 watts and amps capable of 8000 watts( exagerrated on purpose)
If someone likes and buys 4 ohm speakers, they should look for an amp that can drive em..
The hard part is when you find a pair of speakers you love, nominally rated 8ohm but can dip well below that..(dependent on more than one factor)
That's when we ask questions..
Can my Yamaha RS202 handle my Martin Logan Sequel II's..?
ETA: yes I know my ML's are rated 6ohms nominally..
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Unlikely. There are many people who still believe that more power is always better than less power. For a given voltage swing, a lower impedance load will dissipate more power, hence the lower impedance has the marketing advantage.
Up to the 1960s most amplifiers were valve amplifiers which could swing hundreds of volts before their output transformers. For them, driving 16 ohm speakers was actually easier than driving 8 ohm speakers (given a suitable output transformer). Today, with the market dominated overwhelmingly by SS amplifiers, 16 ohm speakers offer nothing to temp the power-obsessed.
That would be a distinctly awful combination. You will need something with at least some guts for those speakers. Will sound come out? Sure. Just nothing close to what the speaker needs to work as designedI think a lot of confusion is due to advertising..
Speakers that are capable of 3000 watts and amps capable of 8000 watts( exagerrated on purpose)
If someone likes and buys 4 ohm speakers, they should look for an amp that can drive em..
The hard part is when you find a pair of speakers you love, nominally rated 8ohm but can dip well below that..(dependent on more than one factor)
That's when we ask questions..
Can my Yamaha RS202 handle my Martin Logan Sequel II's..?
ETA: yes I know my ML's are rated 6ohms nominally..
AudioAvarice
Super Member
Most of my speakers are 6ohm, which I think is a pretty good compromise.
I have a wonderful pair of 4 ohm speakers hooked to an HH Scott early 80'e receiver and it's a fine match. I forgot and switched in a A/V receiver that only does 6 or 8 ohms and you have to set which one you are going to use. It was set on 8 ohm and after 15 minutes the front L&R channels blew. Better that than damage to these speakers imo. My neighbor is currently using the A/V receiver for 2 channel stereo, on the rear L&R channels.
twiiii
Lunatic Member
Just for the fun of it I went over to the Hi Fi News website and being a British publication looked at thier lab reviews of speakers. They don't always match up to Stereophile with graphs but most of the time the person doing the tests does a better job of telling how a particular speakers with its complex impedances effects the amplifier driving them. He is not shy either about the results. Like the composer of this question asked it does seem the manufacturers continue to make speakers that overly stress most folks amplifiers recently just to get a 3 or 4 db more sensitivity. Its really disgusting.
I have always been a 20 HZ up guy when auditioning speakers. Its like the tire add where the old lady throws a tire threw a window asking where's the beef? In my case its where's the bass? Speakers have to be flat down to 30Hz that means down no more than 3 db from 500 HZ. Of course room positing can help, but you guys pulling speakers away from walls really attenuate the low bass. No wonder manufacturers now days are trying all the tricks the can to get 3 or 4 db increase in efficiency when speakers all become less efficient pulled away. You think you are getting clearer upper bass and lower mid range, well you are because you are attenuating the fundamental bass that does cover up. But thats the natural sound of a recording. Also because you are using point source speakers that spread the sound everywhere you are trying to reduce negative early reflections. I get that, too. Then too most folks down want large speakers which is the easiest way to get low bass, But I would rather have line arrays to solve those problems. But thats another pet peeve of mine most popular recordings now days are not natural sounding at all. That went away when Rock and Roll and Disco later became popular. Yes I loved to get out on the dance floor and do my thing as it was fun and everyone was having a good time. But, to sit down and listen to it seriously. Not my favorite cup of tea or Beer or what ever else adult beverage is handy.
Note: Off subject. If you really want to compare turntables , tone arms and phono cartridges Hi FI News is the place to go. Brits really love the LP's and there fore they want to know all about Turntables. Can you imagine a 36,000 Pds VPI direct drive TT that can't compete with a SME model 12 Synergy for 13,000 Pds. That's very disappointing.
I have always been a 20 HZ up guy when auditioning speakers. Its like the tire add where the old lady throws a tire threw a window asking where's the beef? In my case its where's the bass? Speakers have to be flat down to 30Hz that means down no more than 3 db from 500 HZ. Of course room positing can help, but you guys pulling speakers away from walls really attenuate the low bass. No wonder manufacturers now days are trying all the tricks the can to get 3 or 4 db increase in efficiency when speakers all become less efficient pulled away. You think you are getting clearer upper bass and lower mid range, well you are because you are attenuating the fundamental bass that does cover up. But thats the natural sound of a recording. Also because you are using point source speakers that spread the sound everywhere you are trying to reduce negative early reflections. I get that, too. Then too most folks down want large speakers which is the easiest way to get low bass, But I would rather have line arrays to solve those problems. But thats another pet peeve of mine most popular recordings now days are not natural sounding at all. That went away when Rock and Roll and Disco later became popular. Yes I loved to get out on the dance floor and do my thing as it was fun and everyone was having a good time. But, to sit down and listen to it seriously. Not my favorite cup of tea or Beer or what ever else adult beverage is handy.
Note: Off subject. If you really want to compare turntables , tone arms and phono cartridges Hi FI News is the place to go. Brits really love the LP's and there fore they want to know all about Turntables. Can you imagine a 36,000 Pds VPI direct drive TT that can't compete with a SME model 12 Synergy for 13,000 Pds. That's very disappointing.
RVT1K
Super Member
I edited my previous reply...didn't think it through.
You get more power up to the point where the amp can't deliver enough current into the 4 ohm load.
Depending on the design of the amp, it may only be a little more or close to twice the power into an 8 ohm load.
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