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Will I damage my new speakers with low output?

Discussion in 'Home Cinema Speakers' started by woof, Sep 10, 2005.

  1. woof

    woof
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    I am pretty ignornant when it comes to setting up so bear with me. I am looking to slowly replace my all-in-one system (Pioneer DV57) piecemeal with far better separates. First I am looking to replace speakers, but have a concern in whether I can wire in my newly acquired front speakers, which can handle 200W but the processor/amp on the pioneer only has an output rating of 30W/channel (speakers) and output 50W to sub. Have been reading rather contradictory information about damaging speakers with low power, but if I was not going to push the volume button up, would I damage the speakers? This is only a temporary solution whilst I gather money to buy a bigger processor/amp - but do the speakers need to remain quiet or can I use them? Thanks, Mark
    :lease:
     
  2. Steve.EX

    Steve.EX
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    Do a search for the term generically known as "clipping".
    The labelling of the speakers to 200 watts has little or no real bearing. What is of importance is to know their impedance and sensitivity.
    A little research will give you all the answers you require, but to briefly give you some (immediate) idea of compatibilty. If your speakers have a high (nomimal) impedance of 8 ohms and a nice and high sensitivity of say 89db/w/m (this info will all be in the owners manual or onlinje somewhere) then as long as you keep the volume nice and low you shouldn't run into trouble. If your speakers are 4ohms in impedance and say, 86-87db/w/m, then i would think carefully about connecting up your new speakers.
    There is no "conflicting opinion" here. If you have read that putting lots of speakers on a hopelessly underpowered amplifier is a pretty risky affair then that which you have read is correct. To put a "100watt" rated pair of speakers on a 500w amplifier is a really good idea, far healthier for all (components) concerned with very little chance of real world problems. Overdriving speakers is in most domestic situations pretty unlikely. Underdriving them is as common as you like and wrecks speakers and amplifiers.
    Have a read up, theres nothing like understanding for yourself. It is (in essence) a simple mathematical equation with no voodoo involved.
     
  3. Troon

    Troon
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    In summary, you're fine so long as you don't drive your amp into clipping. If you start to hear distortion, back off. 30Wpc should be fine to go quite loud in a normal sized room.
     
  4. Steve.EX

    Steve.EX
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    I have to say i am not to sure about that. All things being equal 30w is not a massive output (barely above valve stuff) and with low sensitivity speakers you will find you are pushing the amp hard to get any sense of volume. This is before we worry about impedance, dynamics etc etc.
    Also of particular note here is that it would seem that the amp in question is an all-in-one number (although in all fairness i have no idea about the actual model itself). It is pretty unlikey that it would be able sustain a distortion free output of 30w across all channel simultaneously, if it in anyway similar to the "all-in-one-box" units i have observed. These units usually have speakers that are deliberately designed to work with a low output (a common trait of the budget speaker). Your new speakers, if of any quality, will probably have less concession to this.
    Also if you are going to drive it to distortion and then "hang it back a bit" it may be an idea to understand what it is you are listening for, particularly with your (presumably) lovely new speakers.
     
  5. severnsource

    severnsource
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    There is almost no chance of damaging speakers with too low a power amp.

    Some people claim that the relatively high levels of HF distortion generated when driving an amp into clipping can burn out tweeters. This is a slightly credible theory, but a bit unlikely. Even if you drive an amp hard into clipping most of the energy will still be at low frequencies and I seriously doubt that there would be enough HF energy to damage modern MC tweeters. Any one with any interest in high quality sound would have reduced the level well before the amplifier got to that state.

    There is no other way that a speaker can be damaged by a properly working low powered amp.

    30W is a perfectly acceptable power for most domestic uses. In order to double the apparent sound level you need 10 times the amplifier power. In normal circumstances most listening is done with a power level of less than 1W.
     
  6. Steve.EX

    Steve.EX
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    I would be very much inclined to say that a square sine wave will destroy a driver in very little time whatsoever, having been witness to this on several occasions, (not through my actions i hasten to add).
    Despite, as you say, huge line-sags being most likely resultant of the current demands of large dymanics or phase swings at the lower end of the bandwidth, it will nearly always be the tweeter that suffers given it's coil properties. :) :) :)
     
  7. Steve.EX

    Steve.EX
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    I would still absolutely maintain that placing low impedance, low sensitivity speakers on an all-in-one-box type unit has the a very real world potential for trouble.
     
  8. the mechanic

    the mechanic
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    Sorry I beg to differ. The following text is taken from HERE

    Clipping: - When the amplitude of a signal exceeds the maximum possible level of a device, the part of the waveform which is excessive is "clipped" resulting in a distortion of the sound. If clipping is harsh and prolonged, this can result in damage to the device in question. See also "Headroom". Distortion occurs when an amplifier is driven to play louder than its power supply allows and the result is clipping. This state can cause loudspeaker damage. It is of particular importance with digital audio recording because the clipped waveform contains an excess of high-frequency energy and the sound becomes hard and edgy. With analog linear recording it is standard to record as hot as possible; with digital non-linear recording, recording too hot will result in disastrous clipping.

    And also the definition of headroom :-

    HEADROOM: The safety margin in dBs between the highest peak signal being passed by a piece of equipment and the absolute maximum level the equipment can handle. The difference in dB's or watts etc between the highest level of a sonic signal that is being produced, and the highest level that is capable of being produced without significant distortion/ spontaneous combustion! A sonic system always sounds at it's best when it has lots of headroom, and at its worst when there is no headroom at all, as clipping may result.

    I think I trust the "experts" rather than myself, or anyone else for that matter. No offence intended BTW.... :D ....

    Graham.
     
  9. severnsource

    severnsource
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    Yes, playing a 30 watt HF sine wave for a prolonged period will destroy some tweeters, but I rather thought that we were talking about domestic use, not playing high level tones.
     
  10. severnsource

    severnsource
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    None taken. Try looking at http://www.bcae1.com/2ltlpwr.htm for an opposite opinion - the level of expertise looks to be at the same level as the site you linked to!

    Actually, the quote you give about clipping doesn't stand up to careful reading. For instance 'If clipping is harsh and prolonged, this can result in damage to the device in question.' This implies that prolonged clipping can damage equipment other than loudspeakers. Whilst theoretically possible, for instance an inadequately heat sunk amp driving an excessively low impedance, it is so unlikely as to be laughable.

    And 'It is of particular importance with digital audio recording because the clipped waveform contains an excess of high-frequency energy and the sound becomes hard and edgy. With analog linear recording it is standard to record as hot as possible; with digital non-linear recording, recording too hot will result in disastrous clipping.' sounds an awful threat, but it is actually talking about recording, not power amp clipping and is completely irrelevant to the issue of loudspeaker damage.

    Note also the vague use of the word 'can' in 'This state can cause loudspeaker damage.' In other words the author of the article has heard the long standing rumours about speaker damage and is putting in a get out just in case.
     
  11. woof

    woof
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    Many thanks for all your replies, and of course still unsure as to what to do. It is only meant to be a temporary measure, until I can buy a decent processor/amp - so maybe this has just gone up the list of must haves. Perhaps I should get a second-hand amp/processor to tide things over - if so what would be the minimum output needed to not damage speakers - something like 80 or 100W/channel? If it helps, volume control never gets high, due to the joys of being married :D
    Cheers again, Mark
     
  12. woof

    woof
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    "The labelling of the speakers to 200 watts has little or no real bearing. What is of importance is to know their impedance and sensitivity."

    They are audiovector Mi3 - 8ohms impedence, 91dB sensitivity
     
  13. Steve.EX

    Steve.EX
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    The figure that you quote "indicate" to your speakers being an amp friendly load.
     
  14. Steve.EX

    Steve.EX
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    With my own eyes and ears have i obviously witnessed the "impossible". :)
     
  15. Steve.EX

    Steve.EX
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    Interesting link however.
     

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