What is a cost effective way to level match, for comparing different hifi components?


Over the next little while I am planning on trying out some new DACs in my stereo system, and I know that it is important to make sure that sound levels are carefully matched when comparing. So I would like to ask others here how they do this? I realize that these days we all have smartphones and can download apps to measure SPLs. Is this accurate enough for careful comparisons. I wouldn’t mind getting some ideas from others on how they do this, and what might be the best way.
troidelover1499
of course, Roger really was a genius, creator of lots of legendary high end gear for storied firms including his own Music Reference.


If your listening skills are so frail you are deceived by a few dB pack it in, you need a new hobby. 
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Level matching is total BS. Play your system where it sounds best for you. Compare the best sound you can get at the level that works for you. No need for scientific measurement, best sound is best sound. Just adjust the volume to YOUR normal/comfortable level. Every system has a different volume level that is the sweet spot. No need to level match apples and oranges. Use YOUR listening volume as the deciding factor.