Topic: Impedence Question on Receiver

[Courage]

Sorry for being a noob but i have a question...

On my Yamaha RX-V2600, in the advance settings there is an option where i can change the impedence of the speakers that i will be connecting from 6 to 8 ohms. If i will be connecting 4 speakers with 8 ohms(front L and R, Surround L and R all of them are 8 ohms) and one with 6 Ohms(Center) what impedence settings should i put to my receiver? 6 or 8 ohms?

So basically sa 5 speakers na kakabit ko 4 of them are 8 ohms and 1 is 6 ohms...What ohms settings kelangan ko piliin?

Thanks to anybody who will answer this....

[guido]

expert reviewers always say keep it at 8ohms

Choosing the Speaker Impedance

Yamaha still ships their receivers with the dreaded impedance selector switch. Our advice as always is to use the "Minimum 8-ohms" setting regardless of the impedance of your speakers. See our editorial note below for further elaboration.

Editorial Note about the Impedance Selector Switch
I recommend the "Minimum 8-ohms" setting even for 4-ohm speakers of moderate efficiency ( > 89dB SPL). Yamaha includes a" 6-ohm" setting to satisfy UL heat dissipation requirements when driving 4-ohm loads, as well as easing consumer concerns about driving low impedance loads. These switches step down voltage feed to the power sections which can limit dynamics and overall fidelity. My advice is to keep the switch set to "Minimum 8-ohms" regardless of the impedance of your speakers and ensure proper ventilation of the Receiver. Using the 6 ohm setting will reduce power output to your speakers about 15-20% and thus cause higher frequency of amplifier clipping if driven too hard which can damage your speakers.

from this site

http://www.audioholics.com/reviews/receivers/yamaha-rx-v659/rx-v659-system-setup-configuration

[JojoD818]

+1, but only if you know what you are doing. 

selecting lower impedance settings for 4 or 6 ohms loads is just a safety thingy, if you'll go the other way then I suggest added cooling or even forced ventilation.

[Courage]

So basically dapat 8 ohms ang setting nang receiver ko kahit isa sa mga speakers out of 5 ay 6 ohms and the rest is 8 ohms? Tama po ba mga sirs?

[at_sunset_blvd]

8ohms lang Brader to be safe 

[ATJr.]

if you want to be safe, you can set the amp to 6 ohms, effect will be lesser power, lesser heat, but you can use your 4 ohm speakers and you will not know the difference.....

this is the meaning of this quoted comment:

I recommend the "Minimum 8-ohms" setting even for 4-ohm speakers of moderate efficiency ( > 89dB SPL). Yamaha includes a" 6-ohm" setting to satisfy UL heat dissipation requirements when driving 4-ohm loads, as well as easing consumer concerns about driving low impedance loads. These switches step down voltage feed to the power sections which can limit dynamics and overall fidelity. My advice is to keep the switch set to "Minimum 8-ohms" regardless of the impedance of your speakers and ensure proper ventilation of the Receiver. Using the 6 ohm setting will reduce power output to your speakers about 15-20% and thus cause higher frequency of amplifier clipping if driven too hard which can damage your speakers.

even if the amp is set for 8 ohms, you can still use a 4ohm speaker, with greater than 89db efficiency, this what the manufacturer is saying.....

using a 4 ohm speaker on an amp that normally does 8ohm means increased power and increased heat dissipation, what happens in an amp that is set for 6 ohms is that the rail voltages are lowered so that there is lesser heat lost in the output stage as a result.....this is the technical explanation if you can follow me....

If i will be connecting 4 speakers with 8 ohms(front L and R, Surround L and R all of them are 8 ohms) and one with 6 Ohms(Center) what impedence settings should i put to my receiver? 6 or 8 ohms?

tipid sa kuryente yung 6 ohm setting...

[JojoD818]

Lowering the impedance setting means lesser heat but not lesser power if you will also use a lower impedance speaker.

So basically dapat 8 ohms ang setting nang receiver ko kahit isa sa mga speakers out of 5 ay 6 ohms and the rest is 8 ohms? Tama po ba mga sirs?

Tama po sir.

8ohms lang Brader to be safe 

Ano ang 8 ohms lang to be safe?

Paki linaw lang yun statement para sa mga newbies, baka magkamali ng pagkakaintindi sir.

Hindi mo siya ilalagay sa 8 ohm setting para maging safe, kaya mo siya ilalagay dun para maximized yun receiver since puro 8 ohms lang naman ang load (except for one that is 6 ohms). Now, kung gusto mo talaga na maging safe, sa 6 ohms mo ilagay yun impedance setting ng receiver tapos lagyan mo ng 8 ohms na speaker loads, malamang hindi na uminit yun amp pag ganun underloaded siya.

[Onkyo606]

^ so kung may options to choose either 8 or 6 ohms sa receiver and your speakers are 8 ohms, its better to choose 6 ohms sa receiver brader jo?

does it also follow na kung may options to choose either 6 or 4 ohms sa receiver and you have 6 ohms speakers, its better to choose 4 ohms?

[JojoD818]

^ so kung may options to choose either 8 or 6 ohms sa receiver and your speakers are 8 ohms, its better to choose 6 ohms sa receiver brader jo?

does it also follow na kung may options to choose either 6 or 4 ohms sa receiver and you have 6 ohms speakers, its better to choose 4 ohms?

ayan na ang sinasabi ko hehehe...

the statement in my previous post means that for "safety", nothing beats an unloaded amp, sabi pa nga ni Tony matipid daw sa kuryente. yes of course, but that does not certainly mean it is "better" to choose that.

if it were me, I will chose the impedance setting of the receiver to the same impedance as with the load, for clarity's sake 6 ohms for 6 ohms, 8 ohms for 8 ohms.

those dreaded impedance settings were included in there for a reason, not just for show or a conversational piece. it is there for flexibility.

oh btw, the link posted by guido is not a Yamaha (Manufacturer) link right? I think it's from the editor of audioholics. I don't think Yamaha is that crazy to put a feature in their receivers and then post that it is useless.

[Onkyo606]

foloow up brader jo,

i happen to have a receiver than allows me to set it to 4 ohms, saan mas maganda ang performance ng receiver sa 6 ohms with 6 ohms speaker( my current set up) or sa 4 ohms with 4 ohms speaker( my center channel pala yung Dynaudio contour eh hehehehehehe)

[timber715]

foloow up brader jo,

i happen to have a receiver than allows me to set it to 4 ohms, saan mas maganda ang performance ng receiver sa 6 ohms with 6 ohms speaker( my current set up) or sa 4 ohms with 4 ohms speaker( my center channel pala yung Dynaudio contour eh hehehehehehe)

uy, hapgreyd time... 

isa pa brader, ano part ang masisra kung ginamitan mo ng 4 ohm speaker ang 8 ohm reciever?

[JojoD818]

foloow up brader jo,

i happen to have a receiver than allows me to set it to 4 ohms, saan mas maganda ang performance ng receiver sa 6 ohms with 6 ohms speaker( my current set up) or sa 4 ohms with 4 ohms speaker( my center channel pala yung Dynaudio contour eh hehehehehehe)

all else being equal, that would be the same lang brader. for a 4 on 4 setting, the amp will reduce the supply voltage since the speaker will draw more current. personally, I will go for the 6 on 6 because of the increased voltage swing from the amp.

amps are designed naman with some allowance in the amount of supply voltage, kaya lang naman binababa yun voltage supply to allow use of lower impedance loads.

meron kasi argument ang iba na pag 4 ohms ang load at binaba ang supply voltage ng amp mas malapit daw ito sa clipping or mas malamang na mag clip.

[Onkyo606]

all else being equal, that would be the same lang brader. for a 4 on 4 setting, the amp will reduce the supply voltage since the speaker will draw more current. personally, I will go for the 6 on 6 because of the increased voltage swing from the amp.

amps are designed naman with some allowance in the amount of supply voltage, kaya lang naman binababa yun voltage supply to allow use of lower impedance loads.

meron kasi argument ang iba na pag 4 ohms ang load at binaba ang supply voltage ng amp mas malapit daw ito sa clipping or mas malamang na mag clip.

got the information i wanted salamat brader jo, im good with the explanation, konti lang puounasan ko sa ilong ko kase di naman kalaliman

[JojoD818]

isa pa brader, ano part ang masisra kung ginamitan mo ng 4 ohm speaker ang 8 ohm reciever?

yun output transistor/mosfet brader kung walang thermal sensor para mag shutdown ang amp.

para sa mahilig sa sakit ng ulo... these devices are rated at 25*C and must be derated by about 1W/degree C. ibig sabihin, kung yun output transistor mo ay rated for 200W at a temp of 25*C tapos you are operating them at 75*C then 150W na lang ang pwede mo magamit dun, if you breach that SOA (safe operating area) then your transistor will die (short or open).

[JojoD818]

got the information i wanted salamat brader jo, im good with the explanation, konti lang puounasan ko sa ilong ko kase di naman kalaliman

mabuti naman kung ganun brader, kung gusto mo pa ng mas mababaw ganito lang yan...


kung ang size ng brief ay Large, huwag pilitin magsuot ng Small... sasakit ang testicles mo pag ganun diba? pero huwag din naman magsusuot ng Extra Large kasi kakalog-kalog naman. 

[ATJr.]

but that does not certainly mean it is "better" to choose that

if you say "better" in terms of sound quality, i doubt that one can hear that, unless one has "golden ears".......i leave that to the user to decide......

but i'd say there is a savings in terms of electric consumption.....that way 6 ohms is better....the engineer in me says so.....

if the manufacturer says you can use a 4ohm speaker with the 8 ohm amplifier setting provided speaker sensitivity is 89db or better.....we better believe it.....

[JojoD818]

if you say "better" in terms of sound quality, i doubt that one can hear that, unless one has "golden ears".......i leave that to the user to decide......

but i'd say there is a savings in terms of electric consumption.....that way 6 ohms is better....the engineer in me says so.....

the engineer in me said that in the point of view of performance, not in the point of view of one with a set of golden ears... 

of course I agree with the savings in terms of electric consumption, any unloaded amp will surely save up on power though I doubt if it would make a big difference in my wallet's point of view... but since I am the one paying the electric bill, I'd rather match up the amp with the speaker's impedance.

if the manufacturer says you can use a 4ohm speaker with the 8 ohm amplifier setting provided speaker sensitivity is 89db or better.....we better believe it.....

in that particular link, unfortunately, it wasn't the manufacturer who said that.

[ATJr.]

ano part ang masisra kung ginamitan mo ng 4 ohm speaker ang 8 ohm reciever?

it is hard to assume that using a 4 ohm speaker on an 8 ohm receiver will lead to failure, there are aggravating factors that may lead to pagkasira....

kung palaging birit ang patugtog mo.....malapit yan sa pagkasira...kung walang adequate ventilation

an 8ohm speaker will have a dc resistance of anywhere from 5 to 7 ohms, and the impedance of 8 ohms is true only for one frequency, there are dips and peaks with speaker impedance and it is related to frequency....

there is no hard and fast rule here.....

a 6ohm setting will lead to earlier clipping than an 8 ohm setting, that is why the reviewer says stay with 8 ohms......

if you can not discern any difference between the 6 and 8 ohms settings, i'd say go with 6 ohms, or if your listening habit is such that you do not push your speakers that hard......

[markcrenz]

for safety's sake match the amp impedance with that of the speakers. hahaba buhay ng amp, cooler operation, bawas risk sa damage, tipid pa sa kuryente, saan ka pa? bumibili pa nga tayo ng lc & avr to protect our gears, so let's not compromise our receiver with a barely perceptible decrease in output.

the mentioned 15-20% power reduction will only lessen the output by less than 1 dB. try adjusting your receiver volume down by 1 dB, i doubt you'll notice the change in the "dynamics and overall fidelity" 

[Courage]

Thanks for all your help guys... I'll set the impedence on my amp to 8 ohms, temp lang naman ne 6 ohm yung center ibang brand kasi but will be replacing soon with same brand and same impedence...

Thanks again audio and video masters...

[lncc63]

I'm an AV noob but I'm somewhat familiar with this stuff. 

From a theoretical standpoint, I would say it is always best to aim for maximum power transfer.  Whatever power is not completely transfered will show-up somewhere else most often as heat.  Maximum power transfer is achieved when the source (amp) and sink (speaker) are of equal impedance.  So if your speakers are 8 ohms then the output impedance of the amp should be 8 ohms too. 

The problem however is that impedance values are nominal (average, approximate) ratings.  The impedance of a speaker actually changes as it is driven by the amp.  The same is true of the amplifier as it is driven by the pre-amp.   Be this as it may, matching nominal values is still the way to go. 

Now the presence of heat does not necessarily mean things are astray.   Unless your wires are super conductors they will always generate some amount of heat.   The situation to look for is abnormal heat.  Quick touches are a good habit to have,  I've burnt my fingers quite few times while checking for abnormal heat generation in electronic circuits and stuff.

Hope this helps guys.

[ATJr.]

So if your speakers are 8 ohms then the output impedance of the amp should be 8 ohms too.

for solid state amps, the output impedance is not 8 ohms,neither is it 4 ohms nor 2 ohms, it is much much lower and herein the misconception lies......

when the manufacturer says that power is 100watts into 8 ohms, it does not mean that the output impedance of the amp is 8 ohms, what the manufacturer says is that his amp can supply 100 watts into an 8ohm speaker...these are 2 different things....

under 'ideal conditions', a 100 watts translates to 200 watts into 4 ohms and 400 watts into 2 ohms....

but there are limits to what an amplifier can deliver, the transformer can be small so as not to be able to maintain voltages when loads are lower as in 4ohm.....and then there is heatsinking and electronics issues that may arise as a result.....also in an effort to make their amps bullet -proof, manufacturers employ protection circuits designed to either shut down the amplifier, or limit the power......this design related,

in case you are interested to know the output impedance of your amp, it is by definition, unloaded voltage minus loaded voltage devided by output current....

you don't have to take my word for it but this links explains it better than i ever can: http://sound.westhost.com/impedanc.htm

[markcrenz]

  So if your speakers are 8 ohms then the output impedance of the amp should be 8 ohms too. 

amp output impedance is much lower, ideally zero nga.

Hope this helps guys.

it doesn't 

[ATJr.]

Maximum power transfer is achieved when the source (amp) and sink (speaker) are of equal impedance.

true, but then you got the output impedance of the amp wrong it is not 8 ohms....

the amp can be simplified into an ideal voltage source, representing undistorted output in series with its internal impedance, so maximum power transfer happens when your load resistance equals this internal impedance, and it is not 8 ohms....

[ATJr.]

aside from the Rod Elliot papers, the following is lifted of the pages of the TI handbook:
for those of you who are technically inclined, this should fill you in.....

[lncc63]

Those are good links.  Remember impedance ratings are NOMINAL.   Impedance is a function of frequency which is why the author at sound.westhost.com says that an impedance value without mention of a frequency is not very useful.  I have to brush up on the conventions but I seem to remember the measurements are done at 1kHz.  Here's another link: http://www.bcae1.com/compleximpedance.htm

Guys, if you read and understand those links you'll see what I said is correct. 

Cheers and Peace

[ATJr.]

  Remember impedance ratings are NOMINAL

you are correct with regards speaker impedance.....

you are wrong with respect to amplifier output impedance....

these are 2 distinct entities, let's not mix them up please....

[lncc63]

Sorry, yes they should not be mixed up.