# Should adding a preamp make my system louder at -20db?



## superpoppa (May 2, 2018)

I have an Anthem mrx520 powering my 5.2 setup. When listening to movies at -20db the speakers sounded fine but was worried to drive my 4ohm speakers any harder using the integrated amp.

I just added an ATI525NC class D amp which is 300wpc into 4ohms and switched the connection to my Anthem using unbalanced pre outs. My speakers are XTZ M6's that are rated for max 300 watts.

When running the Anthem at -20db now, some reason I expected the spl coming out of the speaker to be higher. Am I understanding this whole thing incorrectly?


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## theJman (Mar 3, 2012)

I use the M6's in my system so I'm very familiar with them.

XTZ lists the Nominal Impedance as 4-8 ohms without saying what load is where in the range. For the sake of argument let's assume average is 6 ohms which is not a very heavy load. Sensitivity is 89dB, so combined with a 6 ohm impedance it shouldn't take much power to drive them. My AVR is 80 watts per channel (discrete) and it does a pretty good job, even when I push the volume.

"I expected the SPL coming out of the speaker to be higher" is subjective so it's difficult to make an assessment by that I'm afraid. How loud you listen, seating distance from the speakers, what type of room EQ has been applied and your personal preferences all come into play. What happens if the MV is -15 or -10, do the speakers get louder and sound OK still?


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## RobbyAce (Jun 4, 2018)

_"I expected the SPL coming out of the speaker to be higher" is subjective so it's difficult to make an assessment by that I'm afraid"._

Yup, it would be tough to even come up with an estimate for that.


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## Wayne A. Pflughaupt (Apr 13, 2006)

People automatically assume that an amp with more power will be louder at every former volume setting. This isn’t necessarily the case. If the amplifier section of the integrated amp, and the new outboard amp, have about the same input sensitivity, then they will both play at the same level at the same volume control setting. The difference will be when you crank it up. The higher-powered amp will have more headroom before clipping. At 4 ohms the ATI has a bit more than double the power of the Anthem, which really only gives a few dB more headroom.

A change in output level (one way or the other) relative to the pre-amp volume control setting will only happen if the new amp has a lower or higher input sensitivity.

Regards, 
Wayne


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