would 5 wwatts per ch make a difference? (Yamaha 750/650)

[dazbug]

Ive almost decided to buy one of these 2 receivers

The yamaha 750 is 100 x 7
The yamaha 650 is 95 x 7

I will be running a 7.1. I dont need upconversion as projector to dvd will be dvi and xbox and HD TV will be component.

Would i be better off with the 650 or the 750?? Will the 5 watts make any difference? as far as i can tell, they have the same internal parts making them identicall except for power.

thanks,

:)

NB I will be running Jamo spekaer that have a sensitivity of 87/88 DB

[MrMcGoo]

In order to increase SPL by 3 db, you must double the amp's power level. If you want to double the perceived sound level, you must increase the SPL by 10 db which takes the ten times the power. In short, 5 watts will make no audible difference.

IMO, both receivers will be under powered due to the low sensitivity of your speakers. Most receivers have weak amp sections and have difficulty driving low impedance loads.

Bill

[dazbug]

MrMcGoo


What receiver would u suggest then in the price range?? or 1400 price range?

Maybe the H/K 630???

I can get a good price on 750/650 thats all.

[dazbug]

OOps, they are actually 92 DB sensitivity.

Will that be better???????

[MrMcGoo]

H/K has very good amp sections. They are very honest in the amp's power output rating. Most receiver manufacturers grossly overstate amplifier power output. H/K is the exception.

The downside to H/K is the processor section. Many users report noise and other issues.

Bill

PS: My recommendation is the Pioneer VSX-55TXi (US model) or its equivalent. Very good amp and very good processor. B

[Illah]

Originally posted by MrMcGoo
In order to increase SPL by 3 db, you must double the amp's power level. If you want to double the perceived sound level, you must increase the SPL by 10 db which takes the ten times the power. In short, 5 watts will make no audible difference.

I have to disagree a bit...

Doubling power doubles volume. 100W vs. 200W, 200W will be twice as loud. You do NOT need 10x power to double volume, otherwise a 200W system would only be slightly louder than a 20W system.

Now, regarding SPL, double the power adds double volume, which is more than 3dB.

--Illah

[RCbridge]

{{I have to disagree a bit...

Doubling power doubles volume. 100W vs. 200W, 200W will be twice as loud. You do NOT need 10x power to double volume, otherwise a 200W system would only be slightly louder than a 20W system.

Now, regarding SPL, double the power adds double volume, which is more than 3dB.}}


This is a true statement a 3db change requires twice the power and to double it takes 10 times power. In the engineering world when we measure power there is a spec 3db point or half power.

[Swampfox]

Here's a quick link:

http://www.yale.edu/ynhti/curriculum/units/2000/5/00.05.10.x.html#e

It is a bit simplistic. The ability of the ear to discern changes in intensity is frequency dependent. A doubling of perceived loudness may only be a 6db increase at best, and over 10db in the extremes depending on the frequency of the sound.

[cburbs]

Another thing to note on the 650 vs 750.
The 650s ypao setup doesn't do the EQ part the 750 does......so if you want the true YPAO function then get the 750.

[mborner]

Illah,

Doubling the power does NOT double the volume. A 10 db increase is required to double the volume. Doubling the power only increases volume by 3 db. You would need 3 times the power to double the loudness. (a 600 wpc amp would play twice as loud as a 200 wpc amp)

Dazbug, at 92 db sensitivity, your receiver's power rating should be fine.

A 5 wpc difference is insignificant. Get the least expensive one.

[matthewt24]

Originally posted by cburbs
Another thing to note on the 650 vs 750.
The 650s ypao setup doesn't do the EQ part the 750 does......so if you want the true YPAO function then get the 750.


How do you know which Yamaha products with YPAO do not include the "EQ part"? Yamaha literature does not distinguish between different levels of its YPAO technology, except for the number of bands (RX-z9: 10-band; RX-V2400 & RX-V1400: 7-band; not sure what the 750 & 650 specs are). But regardless, YPAO is a parametric ("not merely a graphic") equalizer that automatically optimizes room acoustics.

I'm interested in purchasing a Yamaha receiver (RX-V650 or HTR-5760), and I'm confused because I keep hearing that some models have 'better' YPAO than others, and I can't find anything from Yamaha in writing to cofirm this.

[Swampfox]

Originally posted by mborner
. You would need 3 times the power to double the loudness. (a 600 wpc amp would play twice as loud as a 200 wpc amp)

Dazbug, at 92 db sensitivity, your receiver's power rating should be fine.

A 5 wpc difference is insignificant. Get the least expensive one.

Actually you need 8 times the power.

[tvtech1]

Doubling power doubles volume.

No it doesn't...do some research, the answer is out there.

[eli.g]

HE HE Yamaha is still misleading customers[7*100]or maybe 7*40watt

[dsmith901]

The rule of thumb I see from EEs is it takes approximately 10X the power to double perceived loudness. Regardless, 5 watts is virtually meaningless in this scenario.

[cburbs]

Originally posted by matthewt24
How do you know which Yamaha products with YPAO do not include the "EQ part"? Yamaha literature does not distinguish between different levels of its YPAO technology, except for the number of bands (RX-z9: 10-band; RX-V2400 & RX-V1400: 7-band; not sure what the 750 & 650 specs are). But regardless, YPAO is a parametric ("not merely a graphic") equalizer that automatically optimizes room acoustics.

I'm interested in purchasing a Yamaha receiver (RX-V650 or HTR-5760), and I'm confused because I keep hearing that some models have 'better' YPAO than others, and I can't find anything from Yamaha in writing to cofirm this.

I have the 5760 at home right now. It doesn't have that in part of the setup..

This is basically what has been said from another owner and I agree with him
:
"Don't get me wrong, folks. The HTR-5760 is a *very fine sounding* receiver. My "beef" with Yamaha is how they are mis-representing the receiver in the literature. Clearly, the HTR-5760 implements a method of checking your wiring, checking the phase of the speakers, the distances and the levels. However, it does not check the sound quality and make the adjustments via the parametric EQ, since a parametric EQ is not present on this receiver. With that being the case, Yamaha should not be calling it YPAO for the HTR-5760.
Also, I did a bit more digging through the on-line manuals at the Yamaha Web site. I've been able to determine the following:

- HTR-5790: Implements YPAO and has the Parametric EQ feature like the RX-V1400/2400 receivers.

- HTR-5760, RX-V650 and RX-V750: All have YPAO, but don't have the parametric EQ like the RX-V1400/2400 receivers.

I at least thought the 750 would have the EQ, but was surprised after reading through the manual. "

Yamaha's response to this persons complaint:

"In response to your email: The HTR-5760 does have the YAPO feature. The receiver (HTR-5760) employs the Yamaha Parametric Room Acoustic Optimizer (YAPO) technology which lets you avoid troublesome listening based speaker setup and achieves highly accurate sound adjustments. This is all listed on page 25 of the owners manual. What type of
speakers are you using? Are they different brands or different speaker sizes? The only thing that the HTR-5790 as far as YAPO that the HTR-5760 does not is the Equalizing feature. This is only useful if the brands or sizes of speakers for some channels or if you have a room with
uniques sonic characteristics. But over all the HTR-5760 has all of the YPAO capabilities which are needed to utilize this feature in your system. Sorry for any inconvenience and Thank you for choosing Yamaha!"

[Johnla]

Originally posted by RCbridge
{{I have to disagree a bit...

Doubling power doubles volume. 100W vs. 200W, 200W will be twice as loud. You do NOT need 10x power to double volume, otherwise a 200W system would only be slightly louder than a 20W system.


Ummmmm, in case you did not notice. 10 times 20watts, equals 200watts.....
And that will get you a 10db increase in volume. Which is double the volume of 20 watts.

Originally posted by mborner
Illah,
You would need 3 times the power to double the loudness. (a 600 wpc amp would play twice as loud as a 200 wpc amp)


You both are wrong. You need to increase the power by 10 times, to double the actual volume level. In order to achieve the 10db increase in SPL. Which is the accepted "standard" of being double the volume, although some people also say it's as low a 6db. But 10db is the one that is used by most.

http://www.myhometheater.homestead.com/splcalculator.html

[Swampfox]

For the non-math inclined: Adding logs is the same as multiplying non-exponentials. So 3db + 3db + 3 db is the same as 2x2x2.

[Rÿche 1]

Originally posted by MrMcGoo
IMO, both receivers will be under powered due to the low sensitivity of your speakers. Most receivers have weak amp sections and have difficulty driving low impedance loads.

I need to disagree. My RX-V630 receiver drives my 86db sensitivity speakers as loud as I want, with no problem.

[mborner]

Johna, Great link!! That should clear things up.

[dazbug]

thanks for all the info. I think the 650 would be best as its around $300 (AU) cheper over her ein australia!!!!

Yamaha Aus is a rip off :(

well i have until next week to decide, but so far i think 650 seems better?

[dazbug]

bump

[ke4sfq]

I have had an RX-V650 for about a month now and I am very happy with my purchase. The on-screen programming is great. The multiple zone audio works well. The sound is much clearer and crisper when compared to my 3 year old Sony 100W receiver. The YPAO while not controlling the EQ obviously, it did make a big difference in the way the receiver sounded in my room. It made the sound blend better you could say. It sounds more natural and music and movies both sound great now.

My biggest complaint is that when I switch to my DVI DVD player, I can't see the on-screen menus. But what can I expect for under $500!!

[dazbug]

It makes you wonder why they bother increasing it only 5 watts per ch from 650 to 750??

Maybe 100 x 7 looks better when the dealer is trying to sell it to you?????

[filecat13]

Yes, for marketing purposes, 100W is much more attractive to the consumer. It was probably more of a deliberate effort to limit the lower model at 95W to drive customers up one level for their purchase.

What will Joe Schmoe say to his buddy when it's time to purchase?
a) You know 95W is plenty and there's really no useful difference.
b) C'mon, man, 100W is the minimum you can have. You gotta get at least 100."

I'm betting it's "b" in most cases, and Joe's buddy has just been upsold.

(Yes, I know there are other difference in the units.)

[Swampfox]

I wonder if there any substancial differences or they just do the measurements differently? Reminds me of my last job when senior management stated that "profits were up because they changed accounting techniques". I guess they though we were dumb enough to believe it. :rolleyes:

[dazbug]

dEMOING THEM BOTH TOMMOROW, so ill see if the 5 watts is a big difference....lol

[SayersWeb]

I installed the 750 in my "small" home theater and have been thrilled with it. There is little difference between the 650 and 750. If you don't need the learning remote and are sure you don't want the upconversion to compnent, then the 650 should be fine. The 750 does have an extra audio input (me thinks).

The YPAO is fantastic. It actually found that one of my Kappa 5.1 speakers had been wired from the factory with reversed polarity....

These receivers are quite stunning for the cost. It replaced a Sony ES receiver that I paid almost 3x the money. The Yamaha sounds so much smoother and less harsh than the Sony did. I'm very impressed.

[Eyleron]

Are these two Yamahas rated using the same methodology? ie, over the same freq range with same levels of THD?

[ke4sfq]

I belive they are...

[ShagnWagon]

Yamaha rates their amp sections more conservatively than a lot of the other manufactures out there. I think pioneer rates their VSX line at 0.2% THD whereas yamaha rates theirs at 0.06% THD. (Harman/Kardon rates their amps conservatively as well). This is a noteable difference between ratings. Don't worry about yamaha's power ratings, there is plenty of juice there to drive your speakers.

I'd also like to add that I was playing with my SPL meter the other day and discovered that it only took less than 10 true watts of power to reach volume levels of 84-85 dB from about 15 feet away. This was from a McIntosh amp capable of 300 watts of power. My point is you will likely never reach any where near the 95 watts or 100 watts output of your receiver unless you're running VERY inefficient speakers in a LARGE room.

People pay too much attention to wattage specs for receivers. They're all rated at different %'s THD and usually not with all channels driven (which is what you care about for HT). As long as your receiver can deliver 20-40 watts at a low THD with all channels driven, you'll be fine. And either of those yamahas will do that.