what is the difference in ohm's

DAVID SCHOTT
DAVID SCHOTT Posts: 9
edited July 2014 in Speakers
hello I have a nad m25 and it will deliver 400 watts per channel into 2 ohm speakers what does this mean? my mains are b&w 804"s and they are 8 ohm speakers should I be careful how hard I push them I wish there was a way to know how many watts are coming out of my speakers any tips?
Post edited by DAVID SCHOTT on
· Share on FacebookShare on Twitter

Comments

  • Face
    Face Posts: 14,340
    edited July 2014
    RTFM.

    Dynamic power of 220 watts at 8Ω, 385 watts at 4Ω, and 485 watts at 2Ω
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
    · Share on FacebookShare on Twitter
  • pitdogg2
    pitdogg2 Posts: 25,660
    edited July 2014
    I know the internet is just a week or so old .....


    http://nadelectronics.com/products/masters-series/M25-7-Channel-Amplifier


    google is the snot
    · Share on FacebookShare on Twitter
  • ZLTFUL
    ZLTFUL Posts: 5,655
    edited July 2014
    Some day I wonder if these are actually Polk forum moderators creating these inane accounts to ask questions to test our patience...
    "Some people find it easier to be conceited rather than correct."

    "Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
    · Share on FacebookShare on Twitter
  • pitdogg2
    pitdogg2 Posts: 25,660
    edited July 2014
    No they would start a cable thread:lol:
    · Share on FacebookShare on Twitter
  • sk88
    sk88 Posts: 159
    edited July 2014
    Power (Watts) = Voltage (Volts) square divided by Resistive Impedance (Ohms)
    So, if the amp can output 400 watts into 2 ohm speakers, then it would drop to 100 watts into 8 ohm speakers provided that voltage to the speaker terminal is the same.
    • Online - Focal Solo6 BE, Polk PSW10, Focusrite Saffire Pro 24 DSP, Lenovo x220t
    • Music/HT - Lsi25, Lsi9 (Vr3), Lsi7, LsiC, Pioneer SC-68 & BDP-62FD, PS3
    · Share on FacebookShare on Twitter
  • [Deleted User]
    [Deleted User] Posts: 7,658
    edited July 2014
    Hi David,
    Thanks for posting on Polk's forum. Your amplifier produces a certain amount of energy and since the NAD company doesn't know what speakers will be attached to it they list the amount of energy (watts) that can be produced with different loads connected. Very similar to looking at an automobile engine that could be installed in different bodies with different characteristics. All other things being equal as the attached load decreases in impedance (going from 16 ohms to 4 ohms, for example) the amount of potential power increases.
    Keep in mind these power rating are based upon certain test conditions that are static as opposed to what happens when you listen to music. Since your speakers have a frequency dependent impedance, the load is actually changing constantly because each complex frequency, of the music, activates a different section of the speaker's internal crossover. This plus the demand for power is very random the result is that it's impossible to know how much energy is being produced at any instant.
    Imagine putting the average car motor into a car body that gains and looses weight each fraction of a second and is constantly changing speed. Then times this by the number of speakers being powered, as someone on the forum once said, it's a wonder there's any recognizable sound at all.
    Regards, Ken
    · Share on FacebookShare on Twitter
  • Dropthebeat
    Dropthebeat Posts: 154
    edited July 2014
    sk88 wrote: »
    Power (Watts) = Voltage (Volts) square divided by Resistive Impedance (Ohms)
    So, if the amp can output 400 watts into 2 ohm speakers, then it would drop to 100 watts into 8 ohm speakers provided that voltage to the speaker terminal is the same.


    nevermind.
    Yamaha V1800 receiver along with a NAD 2600a and 2700a .
    Sda 1c - my new favorite speakers
    Rta 8,11tl,15tl
    Monitor 10 and 12
    Marty sub 18" still in the works
    Klipsch sw12-2
    Hobbies turn into addictions .
    · Share on FacebookShare on Twitter
  • tonyb
    tonyb Posts: 33,001
    edited July 2014
    DAVID SCHOTT wrote: »
    hello I have a nad m25 and it will deliver 400 watts per channel into 2 ohm speakers what does this mean? my mains are b&w 804"s and they are 8 ohm speakers should I be careful how hard I push them I wish there was a way to know how many watts are coming out of my speakers any tips?

    Welcome David,

    Your amp is probably pushing around 100 watts at 8 ohms, kinda on the light side for your speakers so I wouldn't go too heavy on that volume dial. Don't be fooled by watts, it's current that feeds speakers and makes them perform to their fullest. Usually in amp specs, this is better noted in the "amperes peak to peak" number...if so stated. Most good amps have around 50-100+ per channel in amperes.

    What you want is a hefty power supply in an amp for harder to push speakers. Watts don't always equate to how well an amp is built. Lots of info on this forum to keep you busy for awhile, dig up some threads on amps/powering speakers, etc.

    Again, welcome and enjoy the forum.

    Crap, that sounds like I work here. lol
    HT SYSTEM-
    Sony 850c 4k
    Pioneer elite vhx 21
    Sony 4k BRP
    SVS SB-2000
    Polk Sig. 20's
    Polk FX500 surrounds

    Cables-
    Acoustic zen Satori speaker cables
    Acoustic zen Matrix 2 IC's
    Wireworld eclipse 7 ic's
    Audio metallurgy ga-o digital cable

    Kitchen

    Sonos zp90
    Grant Fidelity tube dac
    B&k 1420
    lsi 9's
    · Share on FacebookShare on Twitter
  • BlueFox
    BlueFox Posts: 15,251
    edited July 2014
    pitdogg2 wrote: »
    I know the internet is just a week or so old .....


    http://nadelectronics.com/products/masters-series/M25-7-Channel-Amplifier

    "7 X 160 watts Full Disclosure Power,"

    First time I have seen the term "Full Disclosure Power". Are lawyers writing specs now? :smile:
    Lumin X1 file player, Westminster Labs interconnect cable
    Sony XA-5400ES SACD; Pass XP-22 pre; X600.5 amps
    Magico S5 MKII Mcast Rose speakers; SPOD spikes

    Shunyata Triton v3/Typhon QR on source, Denali 2000 (2) on amps
    Shunyata Sigma XLR analog ICs, Sigma speaker cables
    Shunyata Sigma HC (2), Sigma Analog, Sigma Digital, Z Anaconda (3) power cables

    Mapleshade Samson V.3 four shelf solid maple rack, Micropoint brass footers
    Three 20 amp circuits.
    · Share on FacebookShare on Twitter
  • DAVID SCHOTT
    DAVID SCHOTT Posts: 9
    edited July 2014
    THANX FOR THE REPLY WILL BE CAUTIOUS MY ROOM IS ONLY 12X12 sqft. THIS AMP DOES HAVE A ANTI CLIPPING FEATURE WHICH I SWITCHED ON BUT I DONT THINK I WILL REACH THAT LEVEL OF VOLUME BEAUTIFUL AMP THOUGH PROBABLY THE BEST FOR THE 3500 PRICE RANGE. DAVID
    · Share on FacebookShare on Twitter
  • pitdogg2
    pitdogg2 Posts: 25,660
    edited July 2014
    DAVID SCHOTT wrote: »
    THANX FOR THE REPLY WILL BE CAUTIOUS MY ROOM IS ONLY 12X12 sqft. THIS AMP DOES HAVE A ANTI CLIPPING FEATURE WHICH I SWITCHED ON BUT I DONT THINK I WILL REACH THAT LEVEL OF VOLUME BEAUTIFUL AMP THOUGH PROBABLY THE BEST FOR THE 3500 PRICE RANGE. DAVID

    careful on the caps buddy we don't like being yelled at...

    DAVID SCHOTT wrote: »
    BEAUTIFUL AMP THOUGH PROBABLY THE BEST FOR THE 3500 PRICE RANGE. DAVID

    that is one BOLD statement in that price range one can find amps that will run circles around that thing. Not to mention its not all about volume.
    · Share on FacebookShare on Twitter
  • don0
    don0 Posts: 78
    edited July 2014
    pitdogg2 wrote: »
    careful on the caps buddy we don't like being yelled at...


    Why is caps considered yelling? It does not hurt my ears.
    · Share on FacebookShare on Twitter
  • BlueFox
    BlueFox Posts: 15,251
    edited July 2014
    It hurts my eyes, which is just as bad.
    Lumin X1 file player, Westminster Labs interconnect cable
    Sony XA-5400ES SACD; Pass XP-22 pre; X600.5 amps
    Magico S5 MKII Mcast Rose speakers; SPOD spikes

    Shunyata Triton v3/Typhon QR on source, Denali 2000 (2) on amps
    Shunyata Sigma XLR analog ICs, Sigma speaker cables
    Shunyata Sigma HC (2), Sigma Analog, Sigma Digital, Z Anaconda (3) power cables

    Mapleshade Samson V.3 four shelf solid maple rack, Micropoint brass footers
    Three 20 amp circuits.
    · Share on FacebookShare on Twitter
  • tonyb
    tonyb Posts: 33,001
    edited July 2014
    pitdogg2 wrote: »
    that is one BOLD statement in that price range one can find amps that will run circles around that thing. Not to mention its not all about volume.

    Indeed.....3500 ? I can think of a hundred amps or so I would rather have at that price point. As long as the OP is happy though, eh....so what.
    HT SYSTEM-
    Sony 850c 4k
    Pioneer elite vhx 21
    Sony 4k BRP
    SVS SB-2000
    Polk Sig. 20's
    Polk FX500 surrounds

    Cables-
    Acoustic zen Satori speaker cables
    Acoustic zen Matrix 2 IC's
    Wireworld eclipse 7 ic's
    Audio metallurgy ga-o digital cable

    Kitchen

    Sonos zp90
    Grant Fidelity tube dac
    B&k 1420
    lsi 9's
    · Share on FacebookShare on Twitter