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Ohms and Decibels HELP!!

Discussion in 'Home Cinema Speakers' started by cutes6, Sep 24, 2001.

  1. cutes6

    cutes6
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    Hello

    I have a pair of Reference Lumley 3.5 front speakers and they are superb. They are 4ohm / 90 decibel rating and here lies my problem.I am now very into HC and have various other speakers hooked up all 8 ohm.

    As most other speakers are 8 ohm / 96 decibel will I ever be able to match all the speakers,my understanding is I would be able to match the volume output at a certain amp volume level but this will not be constant throughout the amps volume range is this right?How do I solve the ohm mismatch is it important?

    I want to keep my main speakers and presently I am looking for a new Amp, is there one on the market that can provide different ohm's for different channels (if important)and assuming I am wright about the decibel issue how do I cope with that?Or wil I have to bite the bullet and change my main speakers(very very last resort)

    For those that are in the Know what do I do !!

    Any advice would be greatly appreciated,thanks
     
  2. TR4@afordham.freeserve.co

    TR4@afordham.freeserve.co
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    I 'll have a go.. the decibel number is a guide to the speakers sensitivity. This means the speaker may sound louder or quieter depending on its sensitivity for a given power input or a given constant volume setting. The higher the sensitvity number the louder or the more efficient that speaker is percieved to be. I think this is a factor of the construction of the speaker. For example if the cone assembly is real heavy then it will move less than a lighter cone for a given power input. (Force = Mass x acceleration). So I reckon if the AV amp is able to adjust the volume levels for each speaker (or pair) then you should be able to match the volume levels for each speaker. However, this is no gurantee that the speaker will remain at this sensitivity throughout the volume range. Ie if the construction is poor then the speaker may be a little more sensitive at lower volumes than say higher volumes. So my advice - try to match the dB numbers as best you can and stick to the good manufacturers.
     
  3. cutes6

    cutes6
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    Al

    Thanks for that,cheers
     
  4. Reiner

    Reiner
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    My try: dB is a measure for volume when related to speakers. Sensitivity of a speaker states the volume level at a pre-defined input level.<br />It is correct to say the higher the figure the easier the speaker is to drive.

    A speaker with 4 Ohm presents a higher load to an amp than a speaker with 8 Ohm, but any proper (AV) amps should be able to handle that.<br />If not, buy another amp. <img src="wink.gif" border="0">

    A mix and match of different Ohm and Sensitivity levels is possible and should not result in a difference in volume if you have initially calibrated all channels with a SPL meter, using the test tone generator of the amp or from a e.g. DVD.<br />The difference in the speaker will hence only result in how much load it put on the amp, or in other words, how much power the amp has to deliver.
     

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