Question about amps

Discussion in 'Amps, Pre-Pros & Receivers' started by Hostility, Oct 16, 2013.

  1. Hostility Full Audioholic

    Hostility
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    well its been a while since ive been on here. Ive changed my setup big time since ive last posted. I am now running a 2.1 movie/music set up. what i came from was :

    paradigm stuido 60v4 front
    paradigm studio cc690 v4 center
    paradigm atom v6 rears
    2 svs pb12nsd
    emotiva xpa-5

    im now running,

    paradigm mini monitor v7 fronts
    1 svs pb12nsd

    all off my anthem mrx300 (was using as pre pro)

    now i did have my mini monitors on my pc set up that was powered by an emotiva mini-x amp, and it seemed like they were more punchy.

    Now i like to listen to my music at low volume anywhere from -45 to -35. I do use my svs pb12nsd but find it to be to boomy for low volume. Now i was thinking of adding a svs sb12nsd for music only and use the pb12nsd for movies. Or i could add an amp something like 150w/ch or at low volume i wont hear a difference at all? For movies i enjoy it, but def notice a difference from when everything was on the xpa-5 (noticed it when i put the studio 60 back on the receiver only).
    Oh also how i listen to music is stream/ iTunes from my macbook air to my emo xda-2, then to my anthem mrs 300.
  2. fuzz092888 Audioholic Warlord

    fuzz092888
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    I think it totally depends on listening levels during HT playback. Adding more power will add more dynamic range and allow you to push the volume up, but if you never play that loudly it may not make any bit of difference. It also depends on the amps at really low power. An external amp *may* give you cleaner power at really low power levels (<1W) and that may also contribute, especially at the listening levels you quoted. From what you describe, I would personally fix the sub situation before moving on to messing with the amps.
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  3. Goliath Full Audioholic

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    You could go from a 150W/ch receiver to a 1.2WK Mcintosh monster and the voltage swings would remain the same - ie the Mcintosh would not deliver any more power than your speakers require at your preferred listening level.

    If you intend on listening at low volumes then adding more power will net you zero benefit as the power demands at low volumes will already be very low. One reason you may have experienced a difference using the XPA-5 is due to a difference in gain level. If you level-matched to ensure identical gain between the XPA-5 and your Anthem, the result would probably result in no sound quality difference.

    The other reason you may have heard a difference with the XPA-5 is due to expectation bias. It can result in all kinds of audible differences which are not directly connected to the amplifier. Only way to know for sure is to listen double blind.
    Last edited: Oct 17, 2013
  4. PENG Audioholic Warlord

    PENG
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    I don't disagree with you for the most part but as fuzz mentioned, it is also possible that an external amp could provide "cleaner" power at low level output from say 0 to 1 to 2W. Given that his AVR is an Anthem I doubt that would be the case as most reputable amp manufacturer such as Anthem should know how to implement negative feedback and/or other techniques to reduce THD+N, CD, IMD etc. to below <0.1% without the side effects of introducing higher order harmonics that weren't uncommon years ago. Just that the possibility is still there especially if we are dealing with the lower end AVRs, even amps, for that matter.
    PENG,
  5. Goliath Full Audioholic

    Goliath
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    Cleaner power, as in lower distortion for a given output? Why would the Anthem not deliver clean enough power between 1-2W? Distortion is a function of output power - at 1-2W, which is a fraction of the output power of any modern amp, the distortion would be microscopic.

    Here is the Anthem MRX300 power output results on the test bench :

    Five channels driven continuously into 8-ohm loads:
    0.1% distortion at 71.4 watts
    1% distortion at 83.4 watts

    It can deliver 93 watts into 2 channels (8 ohm) 0.1% distortion.

    If I reduced the power from 93 watts to 50 watts, into 2 channels, you can add in a few leading zeros to the distortion figure.

    Hypothetically speaking, if the Anthem was clipping with 1-5% THD at 110W and the XPA-5 delivered power cleanly at 0.001% at 110W then I'll certainly concede that in such a scenario the sound should be cleaner on the XPA-5. Clipping is usually something which is difficult to ignore once you've heard it.

    However if the Anthem can deliver 15W at 0.0005%, hypothetically speaking, and the XPA-5 can deliver 15W at 0.00000015% you think one can hear the difference? At 1-2W you could throw in several more leading zeros to that figure. :D

    Amplifiers are usually measured at full output at 0.1% distortion on a test bench using sine waves. You can exceed rated power and increase distortion over 0.1% or you can decrease distortion by reducing power. 0.1% is generally considered to be low distortion - ie clean power.

    I don't think there are people who can pin-point 0.1% from 0.001% at a given power output while listening to program material, but for the sake of the discussion, let's assume people can do this. Let's also assume that differences can be easily heard given all the masking effects at play. If we reduce power and corresponding SPL so that distortion is now 0.001%, do you think people can hear that?

    Any amplifier, even an entry-level Yamaha sub-$400 receiver can muster at least 70W on a test bench at 0.1% THD using sine waves into 2 channels. At 50W, the distortion would be significantly reduced. At 1-2W, the distortion levels would be positively microscopic. I vehemently disagree with the idea that one can hear distortion on a microscopic level. Our ears don't have unlimited sensitivity to very small measurable changes.

    Beyond a certain point it really makes no difference. Back to examples, that Mctinosh amplifier at 1.2KW would probably deliver 110W at 0.00000000000000005% and 1-2W with an additional 10 zeros tagged on. :) Can one hear the difference? Or it is just a numbers game? I'm inclined to think it *is* a numbers game and nothing more.

    Don't get me wrong, it is intuitive to think that a bigger amplifier will deliver cleaner power, and I agree, all things being equal, but if the power is clean enough at your listening levels, does it actually matter if you add another leading zero to the number? Sorry for the very long post, I sometimes get carried away. :D
    Last edited: Oct 17, 2013
  6. 3db Audioholic Overlord

    3db
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    I can only imagine the speakers sounding more punchy during normal listening levels ( between 70db to 75db) rather than low listening levels. Were the speakers in a different locale when you were powering them with emotiva? If so, I would say room acoustics is the culprit and not the amplification. ABout teh sub being boomy, do you have the options to move it around? If so, pull it away from the walls a little to see if it takes teh edge off.
    3db,
  7. Irvrobinson Audioholic Ninja

    Irvrobinson
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    Actually, Gene and others have measured interesting differences in amplifier behavior in the 1W FFT plots. Also, until you approach the output limits of an amplifier measurements have shown that distortion is imperfectly correlated to output level; THD + noise is often flat as a percentage of output for a large part of the power range.
    Last edited: Oct 17, 2013
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  8. 3db Audioholic Overlord

    3db
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    Yes but the OP isn't complaining about noise. Its more a lack of punch. I doubt very much that throwing 300 watts at the speakers will make them sound punchier when one watt isn't being used to power them.
    3db,
  9. Irvrobinson Audioholic Ninja

    Irvrobinson
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    I'm sorry, 3db, but I don't understand your post.
  10. j_garcia Audioholic Jedi

    j_garcia
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    I think what he is saying is that no amount of additional power is going to add the punch the OP is looking for, and I agree. At low volumes, power will not equal punch. "Punchy" in this case isn't exactly easy to define either, since the OP is also talking about two different speakers.
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  11. 3db Audioholic Overlord

    3db
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    No worries. j_garcia paraphrased it correctly. :)
    3db,
  12. AcuDefTechGuy Audioholic Slumlord

    AcuDefTechGuy
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    I always think about subs when talking "punchy" sound.

    Speakers should just sound crystal clear, accurate. The punchy part should be the subs.

    So are we talking about the little speakers not sounding "punchy" ?

    Because for punchy sub sound, Audyssey Sub EQ fixed it for me.

    Maybe the Anthem ARC Sub EQ can fix the punchy bass for you.

    And no, I don't think any amp, preamp, or DAC will fix the punchy problem.

    But subs and processors may fix the punchy problem.
    Last edited: Oct 17, 2013
  13. Goliath Full Audioholic

    Goliath
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    Yes, microscopic measurable differences. Not particularly relevant if you have no hope of hearing it.
  14. PENG Audioholic Warlord

    PENG
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    Did you read the rest of my post? If you did, you should know that I wasn't concerned about Anthem AVRs, but I did say there was still a possibility that some AVRs, especially the lower end products including external amps could do not so good at output below 1W.
    PENG,
  15. Irvrobinson Audioholic Ninja

    Irvrobinson
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    You do like assertions, don't you? The differences are not "microscopic", to use your optical metaphor, at some frequencies they are on the order of 20db or more. You might be correct, that differences of 60db below 1W and 80db below 1W can't heard, but I'm less sure. I am sure I couldn't reliably discern the difference in a comparison test, but I have wondered if such differences explain why some amps give more long-term satisfaction than others. (Spare me the condescending biases lecture. I really don't care which amp I like.)
  16. Goliath Full Audioholic

    Goliath
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    I never knew it was condescending to discuss part of the human condition.
  17. Goliath Full Audioholic

    Goliath
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    What lower end products perform so poorly below 1W? If there were some examples with measurements it would be useful.
  18. PENG Audioholic Warlord

    PENG
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    Sorry, too busy right now to search them out but if I came across one I'll post a link. For now I am just going by memory that I have seen more than once THD+N vs output graphs that show the distortion ramped up towards 0 and I am only assuming that the higher end products shouldn't have that issue or at least much less so but still just an assumption on my part. The only thing I am sure about is that some (may be rare, but they are there) do ramp up to levels I don't feel comfortable with, at the lower output such as below 1 couple of watts and that's where my amps stay most of the time.

    It may sound contradictory but I also feel that the below 1 watt distortion concern cited repeatedly on this site are somewhat overrated because even my very old Denon 3805 appeared to remain welll below 1% at the low output level. I don't have the so call golden ears but for psychological reasons I prefer to go with systems that remain well below the inaudible level of distortions of all sorts.

    Again, I agree to most of what you are saying, I guess I just don't want to totally rule out certain possibilities.
    PENG,
  19. Goliath Full Audioholic

    Goliath
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    Yep, I agree. As long as the distortion is low enough, it shouldn't post any audible problems. Is it possible for modern solid-state amplifiers to be so incompetently designed to produce gross measurable distortion at 1W, at least to the extent that it is audible? IME, I don't think so, but I guess you can never say never. :D
    Last edited: Oct 18, 2013
  20. Hostility Full Audioholic

    Hostility
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    thanks for all the relpies. i kind of had a feeling an amp would not help me out. Now i have not ran arc at my new place yet so im still running off my old arc settings. What im going to try this weekend is shut the sub off and see what it sounds like that way, and also turn it up to see how it sounds. I have a feeling adding a sealed sub might be my answer. Also i never thought of this before, but i could try turning the bass up 1 notch on the settings to see if that helps with a bit more punch as arc does not set that. treble and bass are set both to 0.

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