HELP! 6 Ohms Yamaha Receiver with 8Ohms Speakers

[ihernandez81]

Ok so I just bought a Yamaha HTR5835 which has the following:
Minimum RMS Output for Front Center surround
1kHz, 0.9%THD, 6Ohms...............120W
I just bought some Sony Speakers that are 150Watts Max 8Ohms, does this mean I can't use these speakers with my ssytem? or if I can how will this affect my sound? Not as powerful?
Please help, can someone explain this to me...should I have bought 6Ohm speakers instead?

 

[Nick250]

Your speaker receiver combo is just fine. The 6 ohm/8 ohm thing is a non factor in your system. Hook up the speakers, turn on the reciever, sit back and enjoy.

 

[agarwalro]

I just bought some Sony Speakers that are 150Watts Max 8Ohms, does this mean I can't use these speakers with my ssytem?

The speakers will work just fine. If anyting, the Yamaha amps will have an easier job powering the speakers compared to if you had connected 6 Ohm speakers to it.

or if I can how will this affect my sound?

The sound of a speaker is governed minimally by the impedence when compared to build quality (box design, cross-over design, etc), placement and room acoustics.

Minimum RMS Output for Front Center surround
1kHz, 0.9%THD, 6Ohms...............120W

It was probably MAXimum and not minimum. And it means, if you connect a 6 ohm speaker and play a 1kHz tone, you can get MAXIMUM 120W continuous power from the amplifier at 0.9% THD (Total Harmonic Distortion). If you try to play the signal louder (try to draw more power from the amp., it will start clipping, which can damage the speaker.

 

[ihernandez81]

Yamaha htr-5835 Specs

I went and checked and it does say Minimum, I am posting or trying to post a picture of what I have in the manual.

 

[ihernandez81]

Thanks Nick That's what I'm hoping, to hook it up and turn it on and just enjoy!

 

[agarwalro]

I went and checked and it does say Minimum, I am posting or trying to post a picture of what I have in the manual.

Either it is a misprint, or I am missing something.

Someone, please correct me if I am wrong.
Cheers.

 

[ihernandez81]

Well I have been doing some reading and found some really interesting information...According to this site, my amp should be ok to handle the 8 Ohms speakers but will need to put more power into it in order to drive the speakers...
http://www.hometoys.com/htinews/feb04/articles/polk/impedence.htm

It's a very good site at explaining impedence!

 

[agarwalro]

According to this site, my amp should be ok to handle the 8 Ohms speakers but will need to put more power into it in order to drive the speakers...

If you mean that it will be easier to drive the 8 ohm speakers than the 6 ohm, you are mistaken. I quote from the site you mentioned (bullet point #3 in Practical Advice section) -

"For example, if the power is quoted as 80 Watts into 8-Ohms and 100 Watts into 6-Ohms, this indicates that there is some "reserve current capability," and that the amplifier is capable of working harder when it has to drive a lower impedance (and that's a good thing)."

 

[ihernandez81]

Yeah that's what I mean, it will be harder to power the 8 Ohm speakers than the 6 Ohms because the Pipe is bigger in diameter...according to his example...
But now my next question would be...
If my Amp can put out 120W x 6 Speakers (Including a NOn POwered Sub) And all the speakers in the Box are rated 6 Ohms, when I put 8 Ohms Speakers as the two front speakers with a 150 Watt max, will the amp decrease in the Watts it puts out to each one of my 8 Ohm speakers then? So instead of gettin 120 W that were meant for a 6 Ohm speaker it will be around 100 Watts for an 8 Ohm speaker?

 

[jcPanny]

Amp performance

All receivers can easily drive an 8 ohm load, most can drive 6 ohms, and few can drive 4 ohm speakers.

It all boils down to Ohms Law: V = I * R, Voltage = Current * Resistance. If you consider the receiver's amp stage to be a voltage source, then the receiver must deliver 50% more current into the 6 ohm load to maintain the same voltage. Thus, it is HARDER for the amp to drive the lower impedence (resistance) speaker.

Assuming the amp can deliver the additional current, more power is delivered to the lower impedence speaker because
Power = Current * Voltage.

 

[ihernandez81]

Now that really makes sense, I was still unclear on it even after reading all the forums and stuff. So since the receiver is made to power a speaker with 6 Ohms with enough current to keep the voltage at about 27 Volts to get a power rating of 120W, well at 8 Ohms it won't take as much voltage but need more current to put out the same amount of power 120 Watts...right? because there is more resistance on the 8 Ohm, not as much can get through so it has to feed more current through...