volume control on receivers

[hitendra]

<font color='#000000'>Hi

Normally on receivers, we see the volume control being indicated as -90 Db going to the max of 0 Db.

What does this mean? Also, how is this related to the amplifier's power output and speaker sensitivity?

Also, I have seen elsewhere in these fora that when we calibrate the speakers using a SPL meter, we normally set the volume control to 75 Db (have I got that right??). Does that mean that we have single volume control setting for the HT setup for all inputs? If that is the case, why is it that some CD/DVD play louder than others for the same volume level?</font>

 

[Audioholics]

<font color='#000080'>Everything's relative with respects to volume and encoded levels. The people who mastered one DVD aren't the same who did another, so the levels may be different.

The reason some receivers top out at 0 and count &quot;backwards&quot; is that 0 indicates no attenuation of the full volume/amplification potential of the receiver. The Onkyo I'm reviewing now does the opposite, incrementing up to 100 as the max volume.

Using an SPL meter to set volume allows ensures that all speakers are set to the same SPL level. We do this at 75dB or higher because our setup DVDs or instruction manuals may tell us to - mainly to simulate a more realistic level and also to give you something that is not competing with your air conditioning or other ambient noise which could be over 50dB by itself.</font>

 

[hitendra]

<font color='#000000'>Hawke - thanx for ur reply

So, if 0 db(or 100 as in the case of your system) is the minimum attenuation, or maximum volume, how is this related to the amplifier's power output to the speakers?

Does it mean that at this min. attenuation level, the amplifier is outputting its rated RMS power?

If yes, then it leads me to another point of confusion - suppose we have an amp rated at 100W - and we set the volume control to 75 Db. Let's assume, for simplicity, this outputs 75 W to the speakers (let's say the speakers are rated to handle 90W). Does it therefore mean that the speakers are underpowered ?

Thanx for all your support

Cheerz

</font>

 

[PaulF]

<font color='#000000'>Hitendra,

There are several things that will affect the volume of your music. As Hawke points out the mastering level of the recording is one. Another is variations in the line level signal to the receiver, or conversly, the reciever's sensitivity. Then obviously your volume setting.

So let's say your receiver's analog input sensitivity is 150mV and that happens to be what your CD player puts out, then in theory you should get the rated output from the amp when the volume is at max. However, if the CD player puts our 200mV then the volume will need to be turned down in order to achieve the same output.

75W into a pair of 90W rated speakers should be fine. However what you need to watch out for is clipping as this significantly increases the output power to the speakers. In the second case above with 200Mv in, if you were to turn the volume up to maximum you would likely encounter clipping. Clipping will make the music sound distorted.

Paul</font>