Yamaha HTR-5760 and Polk Audio LSi series

Vince_B · 06-10-2004, 01:39 PM

If the Yamaha HTR-5760 has this specifications:
Built-in 7-channel power amplifier

Front: 95 W + 95 W
Center: 95 W
Surround: 95 W + 95 W
Surround back: 95 W + 95 W

This Yamaha receiver model has switch in the back to flip between 4 or 8 ohms speakers. Although I have read somewhere to not use the 4 ohm setting.

And I'm running this with:

Front: Polk Audio LSi7 (4 ohms each)
Center: Polk Audio LSiC
Surround: Polk Audio LSi7 (4 ohms each)
Subwoofer: SVS PB1-ISD

Does this mean I'm getting 47.5 W out of each speaker? If so, will this be enough for home theater setup for mostly movies? How will this effect if I'm only setting up a 5.1 and not a 7.1?

Thanks in advance.

Chris Brock · 06-10-2004, 01:53 PM

actualyl on the contrary, as the impedence of a speaker drops the power output of the amps will actualyl go up. So you actualyl getting more output from the amp by showing it a 4ohm load. although this does a greater load on the amps and if this becoems to great you can cause the amps to overheat and go into protection. However I dont think you will have any problems. I have been running my 5760 at 4 ohms for abotu a month now with no problems, it actually runs exceptionally cool.

Vince_B · 06-10-2004, 06:32 PM

Chris - which speakers are you running? Are you using any other amplifier?

John Garcia · 06-10-2004, 06:56 PM

Quote:

actualyl on the contrary, as the impedence of a speaker drops the power output of the amps will actualyl go up.

The output doesn't go up, the draw goes up, and this will vary depending on the design and capability of the amp. A GOOD amp will increase with a drop in impedance.

The reality is, this receiver likely does not put out a true 95wpc with all channels driven, but with the 4Ohm switch, you should be OK. The LSis would do well to have more power than that, but it should work, just don't push it.

I have heard that it is not a great idea to use the 4 Ohm switch as well, but I doubt damage will occur.

Wayne Ernst · 06-10-2004, 09:26 PM

Quote:

This Yamaha receiver model has switch in the back to flip between 4 or 8 ohms speakers.

Actually, the switch is for 8 Ohm/6 Ohm and NOT 4 Ohm as originally posted.

**HTF Ads**

David James · 06-10-2004, 11:46 PM

I just sent a question off to Y asking about running 4 ohm speakers on either this or the 5790. While a patiently wait

does anyone else know the answer.

kevin tate · 06-11-2004, 12:28 AM

Members on the Polk Forum have reported that you need a stronger amp to get the most out of the LSi series.

Vince_B · 06-11-2004, 01:31 AM

David - I also sent Yamaha the question, and here's their response...

The Yamaha will be able to power 4ohms speakers without a problem as long as the wattage is a close match to the receivers watts per channel output.

Chris Brock · 06-11-2004, 08:09 AM

that is what I thought they would say. you wont have any problems at all running those speakers. as mentioned above the wattage of the reciever is defintly not going to be a full 95 x 7 but then again there are very few receivers tha actualy put out their rated wattage. Also with the speakers virtualyl every speaker on the market wont be at optimal performace from a receiver amp and would benifit from more power, so i woudlnt worry about that.

by the way my speakers are totally DIY with Vifa and Morel drivers.

David James · 06-11-2004, 09:40 AM

Quote:

The Yamaha will be able to power 4ohms speakers without a problem as long as the wattage is a close match to the receivers watts per channel output.

Thanks Vince

Interesting answer, so I guess they are saying their 100 watt/channel receiver would also provide 100 watt/channel @ 4 ohms

The follow on question then would be, I wonder what position should you put the 8/6 ohm switch?

John Garcia · 06-11-2004, 12:19 PM

You receiver should put out more at 4 Ohms, if it puts out the same 100w, it would struggle with these speakers. I'm sure it will put out a bit more than that at 4 Ohms though.

I'd try the switch on 8 first, and see if it gets hot. If it does, try it on 6.