Friday 1 September 2017

MUSINGS: How much amplifier power do you really "need"? Why not test for yourself?

Much has been discussed about amplifier power over the years; here for a short primer, here for a contemporary take with advice from Crown, and here for an oldskool audiophile take on the matter when dinosaurs and tube amps ruled the land (notice the positive sentiment towards even low power transistor amps compared to the low-wattage tube jobs in this article!).

We often hear the question: "How much power do I need?" A very reasonable query of course when we're thinking of buying a new amplifier.

The answer to that question of course really depends on your needs. The bottom line is that it really is about your context and preferences, the quantity and quality of the amplifier you need can vary based on all kinds of factors. When it comes to quantity, it will of course depend on the efficiency of the speakers you listen to along with size of your room, distance to the listening position, placement of the speakers, and absorptive/reflective surfaces in the space.

For those who have not seen it, I heartily recommend popping over to DIYaudio and check out the thread "A Test. How much Voltage (power) do your speakers need?" What an awesome, straight forward test provided by Pano in that thread!

Basically, here's the procedure:

1. Download one of the test tones which consists of a sine wave at -12dB RMS. I usually just use the 220Hz tone (a good choice if you have a subwoofer and potential high pass in place) but the 120Hz tone is good if you have full-range speakers. Make sure that you can play back that test tone with whatever computer/streamer/DAC you use to listen to music. I have the track on my music server ready for playback through my Raspberry Pi 3 "Touch" device from Logitech Media Server.

2. Play some dynamic music that's not recorded loud nor unnaturally compressed. This allows you to set the amplitude of your preamp+amp(s) to reflect approximately the loudest volume setting you'd use when listening to more "naturally" recorded music. Maybe 2 or 3 dB above a louder "reference" level you would use which will satisfy the volume demands of essentially all of the recordings in my music library. Remember to turn it up but don't go deaf!

For me, I'll use a classical album like Eiji Oue & Minnesota Orchestra's Stravinsky: Firebird, Song of the Nightingale, Rite of Spring (Reference Recordings, 1996, DR19, average RMS amplitude around -25dB). Maybe John McLaughlin, Al Di Meola, and Paco De Lucia's Passion, Grace & Fire (1983, DR15, about -20dB average RMS amplitude). For pop/rock lovers, how about good 'ol Dire Straits' Brothers In Arms (1985 first pressing, DR16, average RMS level around -24dB).

Remember that when we listen to music, typically only a handful of watts are needed. It is in the dynamic transients that demand brief bursts of power from our amplifiers and it is during these times that you need the extra horsepower so as to avoid transient clipping for high-fidelity playback.

Leave your volume control at the louder reference level after listening to your dynamic album of choice (with maybe 2 more dB's for "good measure").

Here's a view of my room the other day for context:

3. Now take your voltmeter, set it to AC scale and apply the probes to the speaker terminals. Typically for most dynamic speakers, we don't expect a huge voltage across the terminals, use something like a 20-50V range on the meter. Don't use too large a scale or you might run into issues with low-voltage accuracy.

4. Play the test tone (220Hz or 120Hz) over the speakers now. Depending on how loud you set the volume level at, this can be rather unpleasant - use ear plugs if needed. And while it's playing, measure the voltage across the speaker terminals. Take care not to short out the terminals!

So, what voltage do you get?

8.35V across the speaker terminals; note that I'm running a bi-wire Canare 4S11 speaker cable (not that I feel this makes an audible difference) and using the surprisingly accurate, versatile, and inexpensive Tacklife DM01M multimeter.

5. With that voltage reading, estimate the power you need by just squaring that number... For me it's 8.35 x 8.35 = ~70 Watts RMS max into an 8-ohm load.
If you're wondering why simply squaring the voltage will do the trick of estimating peak RMS power needed, it's just Ohm's Law...

V = IR, P = IV
I = V/R, so P = (V/R)V = V^2/R
Since the maximum RMS power for a sine wave is -3dB, and the test tone is -12dB, that means we need to gain +9dB to get the maximum amplitude. This represents a voltage ratio gain of 2.818383.

Therefore, to estimate peak power:
P = [(measured V at -12dB) x 2.818383]^2 / R
P = (measured V at -12dB)^2 x 7.94328 / 8-ohms impedance

In other words, estimated peak RMS wattage across an 8-ohm load = (measured V at -12dB)^2.
So, what I can say from this measurement is that in my 15' x 20' x 8' listening room, with the couch, sound panels, speaker layout, and the Paradigm Signature S8v3 speakers rated as 92dB/2.83V/m sensitivity as pictured above where my sweet spot is about 10' from the speakers, I'd want approximately 70W of RMS amplifier power rated at 8-ohms per channel to achieve the upper listening levels I would likely ever use.

This is of course based on listening to albums with minimum dynamic range compression, obviously also recorded at lower average amplitude. This estimate would easily cover loud, highly compressed pop/rock music with minimum dynamic range. For example, Mick Jagger's recent Gotta Get A Grip/England Lost (2017, DR5, average RMS volume of only -7dB) sounds extremely loud even with the volume control set at the equivalent of 3W RMS peak. Remember, the loss of dynamic range results in the "wimpy loud sound" Mitch Barnett wrote about a few months back. It doesn't take much to make something sound loud on average - but "loud" without much dynamic fluctuation isn't particularly exciting for hi-fi lovers - the tragedy for so many poorly mastered music out there!

Estimating that I would "need" 70W, considering that I am powering my main speakers with 250W (into 8-ohms) Emotiva XPA-1L monoblock amps, I obviously have quite a bit of overhead power to draw from if ever needed.

Remember that the calculations are idealized. Speaker impedance is much more nuanced than a straight 8 or 4-ohm load. If you run a DSP or are EQ'ing, average signal amplitude will typically be attenuated when done right to prevent clipping and you might need amps with a higher overhead (in fact, I set the volume of my system using room correction DSP and turned it off when measuring). At least this test will get us in the general ballpark for an idea of our power requirements.

If we look at the poll result on the thread as of late August 2017, >5 years since inception:

We see that of 588 samples, 70% of those who tried this were happy with <25W (into 8-ohms) in their systems, and 84% would be happy with <100Wpc amplifiers. Those are certainly not unexpected and very reasonable results for home users.

Remember that we're only discussing quantity of power here and not quality. For "quality", well, one would have to consider distortion, signal-to-noise ratio, ability to sustain continuous demands, efficiency, etc. Hard to talk about this unless we focus on specific devices and look at measurements of course. One implication for amplifier measurements is that even with behemoth amplifiers, one must focus on the "quality" of those first few watts and up to 25W which is where most people will be listening with using typical dynamic speakers. I think this reasonably captures the "First Watt" philosophy. Of course folks with speakers using other technologies like ribbon and electrostatic panels may need more current from their amplifiers just as on the other hand there are those with >100dB/W speakers who can get by with just a handful of good quality watts.

Kudos to Pano over at DIYaudio for the test! Certainly a fun, easy and informative exercise for audio lovers...


I saw this at the local shopping center the other day:

"Timeless" vinyl LP as the prop at the local Swarovski store. Laugh now, but I would not be surprised if in 20 years, the currently much maligned CD (especially by analogue-format-lovers) will serve the same purpose as a nostalgic reminder of a time when everyone spun shiny disks. From CD Digital Audio to SACD, CD-V to DVD to Blu-Ray... Remember that the 4.7" (120mm) disk is the most successful physical A/V medium on Earth and no doubt it has had an impact on the human psyche in a way that will be "mined" for nostalgic purposes in the decades to come by marketers.

Sure, while there has been a level of interest in the LP with some younger folks in the last few years, I doubt the emotional bond will remain strong beyond the effect of the Baby Boomer consumer - this easily will be on the decline in the next 5-10 years when it comes to consumer electronics. Note that this has nothing to do with my opinion that vinyl isn't truly "high-fidelity" by today's resolution standards. Rather, it's just an observation about the fact that technology moves on through the generations, fashions come and go, and ultimately it is the human psyche that decides to dig out anachronistic trends that may flourish for a time...

Speaking of flourishing only for a certain amount of time, it's September and the trees are anticipating the fall. This means that there's only one week left to submit your results for the MQA Core Decoding vs. Standard Hi-Res Audio Internet Blind Test. I'll close off the submission page on September 8th.

Remember that MQA has been reluctant over the years to even run A/B comparisons in audio shows. IMO, the likelihood of ever seeing an attempt at studying MQA's effect will be few... I would not be surprised if this blind test will be the largest set of independent results you'll ever see about MQA's sound. If you have the requisite gear, make your entry as "subjects" and send me your results and express your listening experience in the data set.

Hope you're all enjoying the music! Back to school time here in North America...


  1. Just a few extra things that are good to know when looking at speaker and amplifier Power levels:

    It is rather pointless to upgrade to a 75Wrms amp when coming from a 50Wrms amp.
    Just as it is pointless to buy a 100Wrms amp if you already own a 70Wrms amp as the 100Wrms will only play 1.5dB louder. This is just barely noticeable.

    When you want to play twice as loud (about 10 dB louder) you need 10x more power.
    So, you need a 250W amp to play twice as loud as a 25W amp.
    A doubling of power is just 3dB louder which isn't a lot.

    Only look at RMS power levels when comparing amps.
    Even then, 2 amps specified as 40W RMS can still have different amounts of peak power and thus be able to deliver more SPL than the other one.
    One 40W amp may not be the same as another 40W amp.
    Not only in output power but also in other aspects.

    Ignore PMPO power ratings. PMPO stands for Peak Mono Power Output.
    An amplifier with a 100W PMPO rating may well be just 2x6W RMS in reality.

    Music Power is often given in a spec. sheet. This is because that number is more impressive.
    An amp with 80W music power rating may well provide just 50W RMS power.
    In general: The further the music-power and rms-power ratings are apart the crappier the power supply is.

    A (well designed) amp rated as 100W into 4Ohm should provide 50W in 8 Ohm (20V)
    When the values do not double from 8 Ohm to 4 Ohm then the power supply is probably not properly (over)dimensioned or current limiters are present.

    It is usually better to have an amplifier that is capable of driving 4 Ohm (or even lower) impedance speakers, even when the speakers are rated at 8 Ohm.
    Best not to drive 4 Ohm speakers from an amplifier that is only specified for 8 Ohm even though it is not impossible.

    Don't get hung up about power ratings of speakers and amps.
    They do not need to match.
    It is perfectly fine to have 40W rated speakers and drive them with a 250W amp.
    Likewise you can have 250W rated speakers and drive them with a 40W amp.
    The only caveat is... when you hear distortion dial the power back.
    In both situations.

    Also one should realize one can easily blow up tweeters of a 250W rated speaker with an amplifier that is rated at merely 6W.
    When an amplifier clips the tweeter receives a LOT of power and can burn out.
    A tweeter usualy can only handle just a few Watt, even when the speaker itself is rated at 100W or more. A 6W amp fully clipping and distorting can thus destroy a tweeter.
    Here too... when you hear distortion ... dial back the power.

    The higher the efficiency of a speaker and/or the smaller the room is in size the less power you will need to listen to music on satisfactory levels.
    High efficiency speakers in a small room need just a few Watts.
    Low efficiency speakers in a large room may need far above 100 Watts to achieve the same SPL.

  2. Thanks for the article and the DIY link!

    I'm in the process of getting the impedance curve of my speakers (including crossover) and I'm having a hard time to determine if my measurements are good. My goal is to get an accurate power utilisation at a given peaking frequency.

    I was commenting two weeks ago on AK about this subject and people get offended really quick. Big power amp lovers recommend big power amp without any technical our commun sense reasons. Next time I'll share the DIYaudio link and article.



    2. That's exactly what I did, but I'm getting 2 ohms reading. Woofer has a 8 ohm nominal and compression driver 16 ohm nominal. I used different multimeter (one was a fluke 289). My 1k ohm resistance is 1% and measured.

      So my reading are not correct or the crossover and cabinet/horn affect the impedance curve a lot. At this point I don't know Who's wrong.

    3. Well.. it could be the X-over when it is not calculated properly.
      In that case the parallel capacitor across the woofer could be too big in value or the inductance in series with the woofer too small or a combination of those 2.
      In that case the impedance at the lowest frequencies should measure around 8 Ohm though.

      Do you have any other (cheap) speakers you could measure this way ?

      When you measure the DC resistance of the speaker (multimeter) what values do you get ?

      It should be the DC resistance of the woofer + DC resistance of the lowpass filter coil(s) and would expect this to be over 8 Ohm.

    4. The crossover is company made (TAD).

      Reading from 10 to 60hz are realistic, but passed that point the voltage just goes down, and I reach 2,2 resistance. The resistance goes up to 7 ohms at 20khz.

      I have other pairs to try.

      I'm also wondering if the amplifier could goes into a protection mode, since the resistance is high?

    5. Looks like a X-over issue.
      It may have been necessary to equalize or damp the woofer.

      Some amplifiers have a current limiter, others simply run out of juice by a lack of an (over)dimensioned power supply.
      Some amplifiers have no current limiters at all.

      For current limited amplifiers it may not be a problem to drive a 2 Ohm load as long as you don't play as loud that the current limit is activated.
      Current limiters are 'hard clippers' so a distorted bass may indicate either a current limit is reached or the maximum output voltage is reached.
      In these cases just turn down the volume.
      The amp may get hotter than normal when driving low impedance speakers loudly near their clipping voltage which may result in defective output devices.

      When it sounds O.K. and the amp does not get too hot I would not worry about it.

    6. The amp sounds fine. 35w 8ohm, 70w 4 ohm ans 140 ohm.

      It woukd ne fun for me to have the curve and spot spikes with their related frequencies.

  3. Hi again Archimago,
    your post brought me back to 2015 when everybody kept telling me O2 does not have enough power to drive AKG K240DF. And yet all that was required was something like 2.82V RMS (out of 7.5V RMS O2 reserve) to bring K240DF to 100dB. That proved satisfactory for all cases.
    Some people amp to 105dB, some even to 120dB!

    I set my standard peak level to 95dB and never really needed to go above. Simply because at 80dBA my ears start to brickwall limit the sound. So for my intents and purposes, 4mW into power demanding headphones is enough (88dB/mW), while for my DT-250, only couple microwatts suffice.

  4. @Archimago

    Above you say:
    " With that voltage reading, estimate the power you need by just squaring that number... For me it's 8.35 x 8.35 = ~70 Watts RMS max into an 8-ohm load."

    But that's actually 8.71W RMS

    P=Vsq / impedance - so in your case 8.35x8.35/8=8.71W RMS = 12W peak

    1. This comment has been removed by the author.

    2. A quick look in to that thread would have revealed that this simplified calculation takes the 12 dB (factor 4) into account to directly calculate the required peak power. Which still seems wrong as the actual impedance is ignored...

    3. Just do the math yourself. It works for 8 ohms. So everything above 8 ohms won't be an issue. If you have impedance lower than 8, yes it's not valid.

      If you're wondering why simply squaring the voltage will do the trick of estimating peak RMS power needed, it's just Ohm's Law...

      V = IR, P = IV
      I = V/R, so P = (V/R)V = V^2/R
      Since the maximum RMS power for a sine wave is -3dB, and the test tone is -12dB, that means we need to gain +9dB to get the maximum amplitude. This represents a voltage ratio gain of 2.818383.

      Therefore, to estimate peak power:
      P = [(measured V at -12dB) x 2.818383]^2 / R
      P = (measured V at -12dB)^2 x 7.94328 / 8-ohms impedance

      In other words, estimated peak RMS wattage across an 8-ohm load = (measured V at -12dB)^2.

    4. You're correct.
      A 0dBFS sinewave is -3dB in RMS value so indeed +9dB opposite the -12dB test signal.
      So 8x more power is needed.
      That is assuming the impedance is almost a constant 8Ohm which it won't be.
      8x 8.7W = 70W

      I deleted my previous comment as it was not correct.

      With his speakers one would be able to reach 110dB at 1m distance per speaker when 70W is applied.
      But his listening position is at approx 3m so there will be about 101dB per speaker at the listening position.
      There are 2 speakers so 104dB peak will be reached at the listening position in that case.

      Given the fact that the 3 albums he mentioned all had average RMS values between -20dB and -25dB it would be safe to say that Archimago does not play music louder than 77-82dB on average levels which could contain small peaks reaching 104dB.

      With lower DR files the volume control will probably remain way below that max point ...

  5. Right now I don't have the time to do the test. However,I am convinced that for playing dynamic classical music one needs a beefy amplifier. For years I was driving my Quad els57 speakers with their classic Quad 303 amp. When I changed top the far less sensitive Quad 2805 stats (about 83dB), and moved into a bigger house (40 sqm sitting room + 20 sqm annex dining room), the amplifier was strained and when I turned up the wick, the sound became a bit coarse. So I moved up to a refurbished Quad 606-2. Playing at lower levels it sounded exactly the same, but playing dynamic music more loudly the sound was much cleaner and lifelike. In the meantime I have also added a 400 watt subwoofer, which again adds to the dynamic reality. Even so, there are times that I think the system is still a bit challenged. Talking to a Quad engineer he said that in a room of this saze I would clearly benefit from their 2x260 watt monoblocks. Who knows.
    In my 20 sqm study I have another set of insensitive speakers, the Harbeth P3ESR, also some 83 dB. I drive these with a 2x100 watt refurbished Quad 405-2, and that does not seem excessive (and it is about a smuch as these little speakers will take).
    I am always amazed by the nonsense of tiny exotic amplifiers that deliver only 2x40 watt or less, and for huge sums of money. All decent modern solid state amplifiers measure far better than human hearing quality, but many fall far short of the dynamic power needed by many insensitive high end speakers. So the smart strategy is to get as many cheap watts as possible. So for all of 300 euro I recently bought a 2x250 watt rms Yamaha p2500s pro audio amplifier for the system that my 19 year old son is putting together. It is very well made, measures impeccably, and delivers the goods. And it was only the smallest amplifier in their line up.

    1. This comment has been removed by the author.

    2. Yes, the power you need depends on room size, listening position,
      efficiency of the speakers, how loud you want to play and the music
      type/recording quality.

      To make a point:
      When Archimago would have changed his current speakers to your Quads
      or Harbeths and wanted to play equally loud as he does now he would
      need 9dB more headroom.
      This means 8x more power.
      As that was about 70W that means he would need a 2x 500W amp.

      On the other hand.... Should Archimago buy some horn speakers (which
      can sound great) with an efficiency of 100dB/1W/1m then he could use
      much wimpier amps to reach the same SPL.
      In that case he would need 8dB less in power.
      This is a factor 6 so in that case a 2x 10W amplifier would be enough.

      There you have the reason why you can buy amplifiers ranging from 10W
      to several kW.
      To be able to reach realistic levels in a medium sized listening room
      at just a few meters away from your speakers you may need to own an
      amplifier between 20W and 1000W depending on the efficiency of the
      speakers used and the max SPL you would like to reach undistorted.

  6. This comment has been removed by the author.

  7. Indeed. The snag for me is that the only speakers I really like are Quad electrostats and BBC traditon speakers like the Harbeths. The little Harbeth will normally only be used in smaller listening rooms, so its power handling limitation is just about manageable in real life. Bigger Harbeths not only can handle more power, but are also a bit more sensitive (some 85-86 dB)so they are a bit less power hungry. They should be fine in the bigger rooms where they belong.
    My Quads are the real problem: they are insensitive, but they cannot handle huge power. Apparently the 2x260 watt QMP monoblocks should work well with them, but that is not even twice as much power. Adding a separate subwoofer (or perhaps even a second one) is what I decided as first part of my solution - low bass is where most of the power goes.

  8. Quad specs the 2805 at 86dB/1W/1m (8 Ohms)
    The 40V 'program peak' input voltage suggests a 200W/8 Ohm amplifier can be connected.
    That means 55V is the limit for a peak voltage from such an amp.

    I have no idea whether or not the 2805 has a similar crude over-voltage protection inside as the ESL63 which basically shorted the connected amplifier with a 1 Ohm load thereby reducing the input voltage to the membranes because the current limiter of the connected amp kicked in.

    Still 109dB at 1m per speaker is not bad at all and sufficient for most.

  9. Those are the specs for the Quad 2805. Most tests suggest a lower number,however, and that matches my impression, however imprecise. Protection is more sophisticated now. Thus far, I have never managed to trigger the protection circuitry (but that was with just the 2x140 watt Q606-2). The amplifier does get hot when I play my music loud, so I guess it has to work hard for its money.

  10. Interesting test, thanks for posting! I bet this these procedures would get someone in the ballpark if done correctly.
    Personally I am of the opinion that even in home audio you cannot have too much power if your goal is to come close to the dynamics of a live performance. Amplifier quality also enters the mix because watts are useless if the sound becomes strained at higher peaks and volumes. Often people believe that the sound is too loud because it sounds strained or distorted, not because of the actual volume. We would be surprised to know how loud we could / would like to listen if the sound were clean and effortless.
    If you take into account the assumptions below then we would need the following power when listening at a distance of 12' away trying to duplicate the dynamics of a live performance at home-
    speakers 91db 1W / meter= 256 watts / channel to duplicate a piano concert.
    speakers 84db 1W / meter= 612 watts / channel " " "

    rationale and assumptions:
    3db volume increase = double the amplifier wattage.

    Assumptions- 91db sensitivity speakers @1 watt - 1 meter:
    +4db for room effects (95db, "very loud" @ 1-meter)
    @ 6 feet away, 93db (moderately loud)
    @ 12 feet away, 83db (not loud)
    add another speaker (stereo) = +3db, 86db (fairly loud)
    Equating to actual music, a solo acoustic grand piano concert can reach peaks of 109db.
    To achieve 109db peaks:
    (3db gain = 10X power in watts)
    Per above:
    1 watt / channel = 86db at 12 feet away, with room effects and speaker 91db efficient.
    2 watts / channel = 89db
    4 watts / channel = 92 db
    8 watts / channel= 95 db
    16 = 98
    32= 101
    64= 104
    128 watts = 107db
    256 watts / channel = 110 db, reproducing the peaks in a solo grand piano concert at a distance of 12' away.

    assuming 84db speaker sensitivity-
    1 watt / channel = 79db @ 12' listening distance.
    2= 82
    4= 85
    8= 88
    16= 91
    32= 94
    64= 97
    128= 100
    256 WPC= 103db
    612 WPC= 106db

    1. You can take it reversed too. You can set your volume to match the lowest notes the grand piano produce during a live performance.

      It doesn't make sense to get an average volume too loud in order to reproduce the live peaks.

      Dynamic conveys emotions. You can get the emotion and intention without the real spl, IMO.

    2. Not talking about volume level- talking about the ability to reproduce loud notes and peaks at a given nominal volume.
      All else being equal a higher powered amplifier sounds better than one with a lower power rating even at lower volume levels- strictly based on its ability to drive the speakers instantaneously.

    3. Your talking about SPL and power which equal how loud you listen to your music.

      A grand piano certainly has 110db peaks at a given distance. If you sit farther you'll get a different spl peaks. It's very suggestive IMO. SPL is meaningless without distance. I didn't find yet informations that add distance on venue or concert. And it will always change depending on place.

      I think it would be more accurate to say that if someone wants to reproduce a grand piano concert in royal Albert hall, siting in the 4th row. I have yet to find informations like this. I know a couple of people did some measurements and posted in part express's forum.

    4. As for "volume", for me a critical listening session, everything quiet in the house and I'm relaxed 80db is too loud. But lets assume that's my listening level ans that there's a 25db peak :

      80db + 25db = 105db
      According to your numbers we are at ~ 64w.

      Still far from 256w.

      So an average listening level of 85 db is needed to get 110 db peaks. 85 db is too loud, for me for a relax, critical listening of a grand piano concert.

      But I understand why someone wants high power amp. I just don't think those audiophile statements like : you need a lot of power, or audiophiles listen to an average of 90db, are a good thing for passionate people.

    5. Hey guys, thanks for the passionate discussion :-). Back-to-school first week of September has been busy so haven't been around as much.

      Yeah, I think it's seductive to think about the amount of power we "need" to achieve these peaks like 106dB in real-life venues and concert halls.

      I'm with Yan T-C on this though. The test I think is nice because it's targeted more on using typically recorded music and the amount one would actually use in one's listening room. Indeed in a quiet room, without people moving, coughing, no audible traffic noise, low background noise, I personally would have trouble listening to a recording at an average 85dB as well for extended periods.

      There are few recordings with a truly huge dynamic range... Maybe one could push the volume up to get high peaks like on Telarc's 1812 Overture when the cannons blast; but that's not "staple" listening :-).

  11. When Harbeth's Alan Shaw demonstrated a pair of M40.1 speakers in Holland, the actual amplifier power going into the speakers was measured at well over 500 watts per channel.

    1. You really cannot have too much power. As a veteran of audio shows you notice they generally bring out the really big boxes when demonstrating their wares.

    2. Yes Frans, I am Dutch (as are you, I guess).

  12. Once you go single drivers you immediately start pairing back on wpc. There's magic less than 1 watt if you have the speakers (and the room) to hear it.

    Then again, my 400 watt plate amp is not enough for my sealed sub for what's between 20 and 50 Hz. I need another sub!

  13. OT: LG phone V30 (Archimago's nightmare?)

    In among LG’s V30 upgrades is the not insignificant addition of MQA file decoding. MQA, short for Master Quality Authentication, is among a multiplicity of formats vying to be the standard for audiophiles looking to move beyond compressed MP3s. It was recently added to Tidal Premium subscriptions, and the V30 will be the first smartphone to support it.

    1. Text copied from some website (forgot to mention).

  14. Archimago is it possible to have your email adress? I have a little projet and I have some questions.

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  16. When we consider amplifier power we must remember that ear sensitivity measured in dB rather. We are sensitive to volume-control step 1 ... 2 dB approximatelly.
    2 times is 6 dB. I.e. 25 vs. 50 Watt is 6 dB only.