The new Onkyo RZ50

[lovinthehd]

That sounds about right, but that is not based on volume -15 you based on earlier. In that scenario, my comments still stand. That is it would be a lot less, say 5-8 w, or less than 10 w for sure.

Your best bet is to ignore such videos but use the calculator that has been linked on this forum many times. Or you can use the one from Crownaudio, or Benchmarks. I created a better one that accepts any impedance values but it's done in Excel and it cannot be attached here for others to use.

You can use any of those calculators mentioned and you will see that 32 W for 95 to 98 dB peak is about right.

The part in your linked video that says 3 dB loss per meter is not good though. The fact is, you will lose 6 dB every time the distance is doubled, but in most rooms, you will have room gain that you need to factor in. In your specific example, it just happens that if you follow their system, the result ended up within the ball park.

Back to your volume -15 scenario again, in that case, your amp will output less than 10 W for sure, subject to conditions I mentioned. In that case, it means you actually listen to less than 95 dB peak from your mmp. I can show you how to figure that out later.

I did watch that part of the video, they were using a loss of 6 dB for every doubling of distance....

 

[PENG]

I did watch that part of the video, they were using a loss of 6 dB for every doubling of distance....

Perfect, I thought they said 3, but that's based on OP's post. I couldn't watch the video until later.

3 dB (or a different number) could work if that's with room gain factored in, but it's not a good way, as it can be less accurate depending on a few other factors and assumptions.

 

[lovinthehd]

Perfect, I thought they said 3, but that's based on OP's post. I couldn't watch the video until later.

3 dB (or a different number) could work if that's with room gain factored in, but it's not a good way, as it can be less accurate depending on a few other factors and assumptions.

Ah, see OP's mention of 3dB now....he (video guy) started going into reflections adding back but was taking too long so that's where I stopped.

 

[PENG]

I only used-15 as a reference, as in his video he said once everything was calibrated properly the avr sees 0 as reference level. So -15 would essentially be 15db below reference level.

I am back in front of my PC now, so I can elaborate on the method based on volume -15, to estimate your power requirements.

To be clear, the right way is to do it based on your desired SPL, distance, and speaker sensitivity, but it just happens that ASR has reviewed and measured the RZ50, so there is enough information for us to estimate power requirement based on volume set to -15.

First of all, let's review the available information, from that review:
1) ASR usually (I assume unless otherwise stated, but I could be wrong on that...) use 0 dBFS when digital input such as HDMI is used.
As Amir notes:
Article: Understanding Digital Audio Measurements | Audio Science Review (ASR) Forum

The “level” or amplitude of the signal has a funny scale: dBFS. This stands for decibels (dB) from Full Scale. In digital domain, there is no concept of voltages. Everything is just a number. So we rely on a relative, logarithmic scale. 0 dBFS is full amplitude within the format we have set (24-bit PCM). Since this is a dB scale, every reduction of the dBFS by 6 dB represents halving the analog output voltage of the DAC.

2) Now take a look of the following graph from the review:
Onkyo TX-RZ50 Review (Home Theater AVR) | Audio Science Review (ASR) Forum
See that it is for HDMI input, volume is 62.5, pure direct mode.

So here you can see the Onkyo RZ50, at 62.5 volume, the output is about 5.3 W
According to Onkyo, 82, in the absolute scale, is 0, in the relative scale.

Since 62.5 is 19.5 below 82, it is therefore -19.5 in the relative scale.

That means from the above information, we know the RZ50 would output about 5.33 W (the average of the left and right channels), from the graph below.

Now we know at -19.5 volume, it outputs 5.33 W, then by calculation:

-15, is 4.5 dB higher, using the formula (in the linked page) to convert P2/P1 in dB to P2/P1 in multiples:
dB chart voltage power table conversion sound pressure sound intensity decibel voltage level levels ratio dbu dBA dBm absolute relative acoustic measurement volts watts and pascals database - sengpielaudio Sengpiel Berlin

P2/P1 = 10^(4.5/10) =2.818 in multiples

5.33X2.818 = about 15 W.

Note that Amir's graph is for the 4 ohm load measured results, so for 8 ohms the output would be 7.5 W, that matches up very well with my quick and dirty and rough estimate in my earlier post.

To summarize, if you use the online spl calculator, that is the right way because it is based on actual SPL at your MMP that you target for, and in that case, the results would be as follow:

91.2 dB, one speaker, at 3 meters, assuming no room gain,
94.2 dB, one speaker, at 3 meters, assuming 3 dB room gain.

You probably will get more than 3 dB room gain, but since room gain is mainly from the bass so my suggestion is, don't count on getting more than 3 dB room gain, in order to be on the conservative side.

Still the Onkyo can comfortably output more than 60 W, or much more, into 4 ohms continuously, so for real world movie contents, it should have no trouble driving your 4 ohms (with dips to 2.5 ohms) speakers with ease, if your desired SPL at MMP is 95 dB or even 100 dB, and/or with you volume at -15, or even -10.

Onkyo TX-RZ50 Review (Home Theater AVR) | Audio Science Review (ASR) Forum