What Your Speaker's Sensitivity REALLY Means for Your Power Needs?

Comments · 342

• ER

  @ErinsAudioCorner · 1 year ago (edited) · pinned

  TL;DW<br><br>Most of the time the typical 50-100w at 4ohm amplifier is more than sufficient for most domestic situations. This provides about 12dB of headroom for music with good dynamic range. If you sit further than a few meters away and/or you have low sensitivity speakers (&lt;85dB 2.83v/1m, 4 ohm) then you may find you need more. <br><br>I have a boatload of power available in my personal system but I tend to listen to music with high dynamic range, at higher levels and I also want to cover my bases since I review speakers of all types.<br><br>As always, though, the real answer is: it depends. <br>See video for more details. <br>Use benchmark’s power calculator in the description for your own specific needs.<br><br>Finally, keep in mind the more links you have in the chain (pre-amp, TV, separate DAC, etc), the more you&apos;ll need to be mindful of proper gain structure. If, for example, you use a pre-amp that doesn&apos;t have it&apos;s gain adequately set you may not be getting the full power of your system. I ran into this recently with the WiiM Amp Ultra review where the HDMI source gain was too low and I couldn&apos;t get the volume I wanted. I didn&apos;t know the HDMI had its own gain structure and I was alerted to this by other WiiM owners. I made the necessary adjustments and had plenty of volume afterward.<br><br><br>Edit: A couple of my Patreon members, whose opinions I value, disagreed with my method for these calculations. So I want to embellish a little bit on my logic here. If you look in the graph labels, you’ll see that I am using a-weighting. I do this because bass tends to artificially inflate in-room SPL measurements. The reason for this is bass, below approximately 300 to 500 Hz, for a typical monopole speaker will radiate omnidirectionally. This is then reinforced by the surrounding walls. Depending on preference, bass may be anywhere from 6-20dB vs the midrange. Using a-weighting filters out the lower bass and focuses instead on the upper midrange where our ears are more sensitive. If you measure with no weighting then you might show your system hitting 100dB when the midrange is 85dB. These things matter. <br><br>I have about 3 dB of “headroom“ built into these measurements as well to account for the fact that some rooms may not reflect as much energy or that some speakers tend to be more narrow in radiation. You can adjust for this in your own calculations, if you would like. But for a video, I prefer to err on the side of caution. That’s how I wind up with my recommendation of 50 to 100 W per channel being more than adequate for most domestic living rooms. If you feel this may be an overgeneralization then I recommend removing about 3 dB by cutting the recommended power in half.<br><br>I hope that better explains my logic here.

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• HA

  @Hamstertech2000 · 1 year ago

  Commenting for the Algorithm so your channel will hopefully be the gold standard for Hi Fi audio in the future

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• TH

  @ThePhiDelicTruth · 1 year ago

  Great breakdown, Erin. This is a helpful introduction, and I think a lot of people need exactly this kind of step-by-step explanation.<br><br>That said, watts alone don’t always tell the full story. Once you factor in reactive loads—especially when speakers present inductive or capacitive behavior—things get trickier. Phase angle starts to matter, and suddenly the current requirements shift dramatically even if the impedance number looks the same on paper.<br><br>Would love to see a follow-up video exploring how these factors affect real-world amplifier performance. For example, what happens when an amp runs out of current at certain frequencies due to a nasty phase shift? That’s often where you get that subtle veiling or compression, even when there’s no obvious clipping.<br><br>Looking forward to where this series goes.

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• PG

  @pgansz · 1 year ago

  Finally, a comprehensive and factually correct video on amplifier requirements. Keep it up Erin - objectivity and transparency in speaker design is, and will continue changing the audio industry!

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• DY

  @DynaudioAcademy · 1 year ago

  Good topic. One of my pet peeves: This calculator, like most others, assume 6 dB loss per doubling of distance. This is only true in anechoic conditions, or outdoors. In a large, well-dampened cinema, that may be reasonable, but in a typical living room the distance loss is closer to 3-4 dB per doubling of distance, because so much of the sound is coming from the reverb (that number is based on my own tests, but matches numbers presented by Floyd Toole). So the actual power requirement in the real world, in typical living rooms, is likely a few dB less than what the calculator shows. Doesn&apos;t hurt to have a little extra headroom, but if we want to be accurate, we should account for this as well in my opinion.<br><br>Other than that, I agree with your rule of thumb that most of the time, for most people, 50-100 watts works fine, and in my humble opinion all the academia surrounding it isn&apos;t really necessary - don&apos;t overthink it. Maybe I&apos;m spoiled by mostly working with pretty high end gear, but I don&apos;t even remember the last time I heard clipping from an amplifier... And we don&apos;t make the most sensitive speakers in the world.<br><br>/Otto, Dynaudio Academy

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• TH

  @ThexCatmanx · 1 year ago

  How did you know I was pontificating on the question of How Much Speaker Power Do I REALLY Need? Very helpful video.

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• JO

  @johnwright8814 · 1 year ago

  Something you missed out, is that to appear twice as loud, you need ten times the power.<br>Our hearing compresses to accommodate the wide dynamic range of natural sounds, from pin-drops to explosions.<br>It&apos;s why we use the logarithmic scale of decibels.

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• MI

  @miguela3826 · 1 year ago

  Thank you, Erin! &nbsp;You make this look EZ. &nbsp;I was able to approximately calculate how many WPC I&apos;ll need for new speakers I want to buy. &nbsp; I will be using one of your links to purchase the speakers I have in mind.

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• RO

  @robertwilliams4629 · 1 year ago

  Apparently Erin&apos;s Audio Corner is somewhere predominantly in the right channel.

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• BA

  @bacarandii · 1 year ago

  Thank you. &quot;Watts per channel&quot; &nbsp;was a big marketing gimmick in the 1970s heyday of &quot;Monster Receivers&quot; (yes, before the CD-compression &quot;Loudness Wars&quot; there were amplifier &quot;Wattage Wars&quot;), advertised and measured quite differently than such things are now. I recently saw YouTube videos by Analogholic (&quot;How to Calculate the Amp Power You Need — NO Math Degree Required!&quot; and &quot;Tube Watts vs. Solid State Watts: The Mystery Unveiled!&quot;) that help explain why, with high-efficiency/sensitivity speaker designs that are relatively commonplace today, &nbsp;a 10-watt (into 8 ohms) tube amp could be capable of filling a medium-sized room with music at 80 dB or so, seemingly without strain -- not something that requires a 100+ wpc solid state amp. Depends on the listener&apos;s preferences and the combination of amp and speakers, of course!

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• BA

  @bassxtcy · 1 year ago

  This is one of the few channels for which I give a thumbs up before watching the video.

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• BR

  @brianpowers7689 · 1 year ago

  Absolutely essential information in a great, understandable video. Thank you, Erin!

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