avidyarthy
Well-Known Member
Noob question, I know ..... but was giving a thought to it ... basically, no work pressure in office today, so .......
.......... Idle brain is Devil's workshop ......
.......... Idle brain is Devil's workshop ......
Why 'most' 4 ohm speakers are better to ones with higher impedance?
- Thread starter avidyarthy
- Start date
spirovious
Well-Known Member
Who told you that higher Impedence spk are bad?Where did you read?
CLEARCUT
Active Member
As far as my experience the higher imp the smoothness is the sound. Distortion less sound. It may be because low imp speaker may be difficult one for the amplifier to drive. Peculiarly the mids and highs were too bright or forward in the lower imp speaker. But most of the jamo speakers are 6 or below ohms
avidyarthy
Well-Known Member
My question was ..... in other words ... why most high end speakers have 4 ohm rating?
I am more interested in the quality of sound output. High end here, translates to better sound, right? A Google check would reveal that most high ends are with 4 ohms.
Now, as a 'sound' user, why should I bother whether the amplifier is finding it difficult to drive a speaker pair or not? Obviously, I would have factored it in. Selected a compatible high current amplifier for power hungry speakers.
But, thats not my question .......
I am more interested in the quality of sound output. High end here, translates to better sound, right? A Google check would reveal that most high ends are with 4 ohms.
Now, as a 'sound' user, why should I bother whether the amplifier is finding it difficult to drive a speaker pair or not? Obviously, I would have factored it in. Selected a compatible high current amplifier for power hungry speakers.
But, thats not my question .......
anm
Well-Known Member
it MAY be that to match with most amps, there is greater COMPROMISE.
@avidyarthy
Even I observed most high end speakers have 4 ohm or 6 ohm rating and less sensitivity around 86dB/87dB.
Most top brands when they say 4 ohm it means their impedance through out the frequency spectrum doesn't drop below 4 ohm or when they say 6 ohm the minimum figure stay somewhere 6 ohms and offer linear impedance characteristics.
Most entry level speakers when they say 8 ohms they are claiming that figure at certain frequency range which they don't mention in specs. There may be a frequency range in the spectrum where the impedance may be dipping to say 2ohms or even less which makes it tough for an amp to drive them.
You don't need to worry when a speaker says 4 ohms. All you need to bother is the speaker offering linear impedance which is key to the performance than fluctuating impedance and 90dB+ sensitivity. Sometimes the speaker spec doesn't make sense.
I would like to put here what I observed when I upgraded my speakers. With my old speakers (Mission M32i 8ohms and 90dB sensitivity) I used to feel my amp hood used to get hotter and I feel like switching it off for 10 mins for every 2 hours of running it.
When I upgraded my speakers to Mordaunt-Short Mezzo 2 89dB and 4-8ohm rated impeadance to my surprise the amp doesn't feel its running hotter like before though the later spec doesn't look as promising as before.
From my understanding the excess heat from the amp could be the amp struggled to drive the Missions and on the other hand the M-S Mezzo's are easy on the amp. No offence to Mission users after all the M-S Mezzo's are few times costlier to Missions.
Dude, that is because lower the impedance, lower the LOAD to the Amp and hence higher the Current output by the Amp (IF IT IS CAPABLE OF HANDLING THAT LOW LOAD). If the Amp is capable of driving a 4 ohm load, using them will result in higher power output than 8 ohm (sometimes and theoretically TWICE).
Main thing which boils down here is - if your Amp is capable of providing current enough to drive 8 ohm speakers, when connecting a 4 ohm speaker will introduce DYNAMIC THD which results in voltage being dropped due to lower load impedance. Essentially the output voltage will be unstable during high power application as the Amp will struggle to supply enough current to DRIVE the load and hence will randomly drop the voltage (higher the power output from the Amp, higher the drop (delta) in voltage to compensate for the higher current drain by the speaker).
Gist - Use speakers with LOWEST load impedance supported by the Amp for highest power output by the Amp (again, actual output depends on the stability of the impedance across the sound spectrum and the SPL of the speakers). Using speaker with HIGHER than minimum impedance MAY improve quality as the Amp will generate more STABLE voltage and current at different stage (with minimum drop in delta of voltage at high volume levels). Hence the THD will remain lower at higher impedance while the maximum power output by the Amp will be reduced due to lower current output (due to higher load impedance).
Hope this helps you in choosing the right speakers for your Amp and hope I dint sound Greek to an average audience.
COOLDUDE7808
Active Member
amps will give u the specs - how much it can drive for 8 and 4 ohms ...match that with speakers ....
make sure output of amp > output of speakers ....this will ensure that amp has sufficient power to drive your speakers ...
output is diff from impedance
make sure output of amp > output of speakers ....this will ensure that amp has sufficient power to drive your speakers ...
output is diff from impedance
avidyarthy
Well-Known Member
Latin ..... Tamil ... Malayalam .... Telugu ....
avidyarthy
Well-Known Member
Good article, but, very very theoritical. We do not get to see what is written here, when we start taking a 'real' look around.
square_wave
Well-Known Member
There is no rule like this.
The resultant impedence or impedence vs frequency curve of a loudspeaker is completely dependent on the designers bias / beliefs in the pertinent acoustic attributes and his approach towards this endeavour.
There are stellar examples of great loudspeakers in either camp.
The resultant impedence or impedence vs frequency curve of a loudspeaker is completely dependent on the designers bias / beliefs in the pertinent acoustic attributes and his approach towards this endeavour.
There are stellar examples of great loudspeakers in either camp.
reignofchaos
Well-Known Member
Yup! Writing off loudspeakers simply on the basis of their impedance is ridiculous.
sonosphere
Well-Known Member
Hi Avidyarthy,
I have observed the same... that many hi-end speakers have very low impedances. While we don't see clear answers in above posts, as to why this is the case, there is definitely some common technical design among such hi-end speakers. I am hazarding one guess here... take it with a bag of salt >>
The cone of a speaker "can" behave like pendulum. i.e even when the audio-signal to speaker has stopped it may still oscillate /vibrate for another few milli /micro second, thereby causing "overhang-distortion" compared to original signal.
To stop the above overhang, the cone /suspension /voice-coil may be designed with such stiff damping mechanism that it's "pendulum tendency" is reduced. However the same stiffness also makes the cone much difficult to move. To overcome this difficulty we need more energy (current) to move the cone.
Another reason for low-impedance would be the design of crossover circuit. Though I don't have a theory to explain this.
The aforementioned "stiffness" and consequent higher energy requirement somehow translates to speaker having lower impedances and consequently requiring high-current amps to drive them to their "full potential" (how? I dont have a clue) It is said that a Dynaudio 52 can make sound (just about) even with regular 50wpc amp, however its "full potential" is achieved with a good quality high-current 100wpc amp
However this 4 ohm criteria alone should not be short-listing factor, though it can be considered as one of the indicators to "accurate" sounding speaker. And you should cross-check veracity of this indicator by other observations of the shortlisted speaker.
Regds,
Sonosphere
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avidyarthy
Well-Known Member
Thanks .... at last !
Yes, I too had your theory in mind ... possible. There has to be some explanation to it. This, however, does not hold steadfastly to full-range speakers and ones with horns. Both have @ 8 ohm impedance ... and very high sensitivity (> 90 dB).
However, with the ususal speakers WE generally dabble with (of course, the high end), the specs of 84-86 ... sometimes 90 dB and 4 ohm sets me back thinking .....
Yes, I too had your theory in mind ... possible. There has to be some explanation to it. This, however, does not hold steadfastly to full-range speakers and ones with horns. Both have @ 8 ohm impedance ... and very high sensitivity (> 90 dB).
However, with the ususal speakers WE generally dabble with (of course, the high end), the specs of 84-86 ... sometimes 90 dB and 4 ohm sets me back thinking .....
Reopening an 'Exactly' 1 year old thread. 
The Monitor Audio RX8 are 4 Ohm Speakers. (RS8 and rest of the current and previous mdels in MA silver series are all 6 Ohm though)
We demoed the speakers with my Musichall Amp rated @50w/ch 8Ohms and 100 w/ch 4Ohms. Though the amp showed signs of sweat while driving the RS8 (6Ohms), It drove the RX8 (4Ohms)without any problems. The bass output was also 'bigger' in the RX8.
What is with the 4 Ohm speaker thingy? Is it something to worry about? The demo experience showed otherwise. It was easier to drive. While the general perception is that the 4 Ohm speakers are harder to drive.
So finally, the RS8 is 6 Ohm and RX8 is 8 Ohm. Everything else being equal, which ones to choose purely based on Ohm value and why?
Thanks in advance.
The Monitor Audio RX8 are 4 Ohm Speakers. (RS8 and rest of the current and previous mdels in MA silver series are all 6 Ohm though)
We demoed the speakers with my Musichall Amp rated @50w/ch 8Ohms and 100 w/ch 4Ohms. Though the amp showed signs of sweat while driving the RS8 (6Ohms), It drove the RX8 (4Ohms)without any problems. The bass output was also 'bigger' in the RX8.
What is with the 4 Ohm speaker thingy? Is it something to worry about? The demo experience showed otherwise. It was easier to drive. While the general perception is that the 4 Ohm speakers are harder to drive.
So finally, the RS8 is 6 Ohm and RX8 is 8 Ohm. Everything else being equal, which ones to choose purely based on Ohm value and why?
Thanks in advance.
On a related topic, IMO this link about Current Drive and Voltage Drive may be useful:
http://www.enjoythemusic.com/magazine/equipment/1204/firstwattf1.htm
Sent from my iPhone using Tapatalk
http://www.enjoythemusic.com/magazine/equipment/1204/firstwattf1.htm
Sent from my iPhone using Tapatalk
Danieljohn
Active Member
Cuz they suck more current obviously sound Great
I was thinking if I should post - because I am clearly not an expert or a speaker designer.
Some things to note though - Actually, speaker impedance (4 ohm, 6 ohm, 8 ohm etc.) - which really is nominal or "average" impedance is mostly a useless spec. That is because there is no industry standard definition of how nominal impedance should be calculated.
Just look at any stereophile chart. Most speakers have impedance and phase curves that swings wildly across the audio spectrum. 6 ohm nominal speakers will often dip down to 4 ohms in certain frequencies.
To my limited knowledge, impedance and power capacity of speakers and sensitivity are design tradeoffs that speaker designers make. The type of driver, the type of crossover, the type of cabinet, the size/volume of cabinet - all factor into this. I've often found that mini-monitors (such as Dynaudio) will have really small cabinets that still do better and deeper bass than most other speakers with larger cabinets. But the price they pay is lower impedance - thus requiring stronger amplification - often high current amps.
Then again, the class of the amp matters too. Many Class D amps for example don't really care much for speaker impedance swings. I'm running out of knowledge here - but I am sure experts like Kanwar can probably better comment on this particular advantage of Class D amps.
A very interesting question is - how much amplification power is really needed? This is interesting because many people run speakers successfully with only a few "pure" watts of amplification, while many even insist that even 100-200 watts is not sufficient to properly service the speaker across the audio spectrum.
Danieljohn
Active Member
:clapping:Everything you mentioned is True
hyeah: & As for amplification power it all depends on whether they are Multiway with Complex Passive Crossovers which obviously reduce power levels increases Phase related problems & Active Crossover means Multi Amping requiring more power but its a good way to connect mid & hi or Frd speakers to tube amps [Single Ended means soothing non offensive even order decaying distortion] & the lows to Solid State [Push Pull means little bit offensive distortion but as most of our ears are insensitive to low frequencys does not matter much] Amplifiers & My Fav is here a simple Single Driver type [Which I enjoyed most of my life in a well designed & built Acoustically crossovered TL's with a Lightning Quick 4 ohm 95dB 2-way Mechanically crossovered 10" Frd's ]with or without horn require only a watt or so which I Love the Most Lastly the very important one is how Sensitive the speaker drivers are also depends & TrueArun you have very Good Knowledge:clapping:
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