Speaker Selection

Discussion in 'Speakers' started by Jame pc, May 26, 2005.

  1. Jame pc

    Jame pc Agent

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    I have some questions regarding speakers. If there's a "FAQ" somewhere relating to this, that would be nice too.

    How do ohms relate to speaker selection?

    How does the frequency affect speaker selection?

    How do I make sure my receiver and speaker will work well together?

    The system will be used mostly on low to mid volume levels.

    If it matters, these questions relate to a budget system, maybe a Kenwood VR-906.

    Thanks!
     
  2. John Garcia

    John Garcia Executive Producer

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    The HTF FAQ is here:

    http://www.hometheaterforum.com/htfo...hreadid=120328

    Impedance (your Ohms question) will relate to speaker selection in that you don't want to have too low of an impedance for your receiver to drive. A lower impedance will draw more current. Most receivers are 8 Ohm nominal, but may also drive 6 Ohm speakers, or one or two 4 Ohm speakers without issue, but a full set of 4 Ohm speakers could drive it to clip and damage the speakers or possibly cause it to shut off - many newer receivers have this safety feature.

    Frequency response should be looked at in terms of how you want to handle your bass management, and the bass management capabilities of your receiver. You will want your speakers to cover down to a point that will allow them to blend well with your sub, based on the available crossover points your receiver has.
     
  3. Jame pc

    Jame pc Agent

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    Thanks for your reply John.

    It sounds like 8 ohm's is the way to go. Is there an advantage to 4 ohm speakers?

    Thanks again,
    James
     
  4. Carl P

    Carl P Extra

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    No advantage. You'll be hard pressed to find a pair of 4 Ohm speakers. Most are 8, but there are some 6's out there. Virtually all receivers are happy with an 8 Ohm load.
     
  5. John Garcia

    John Garcia Executive Producer

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    8 Ohm is "normal" for home audio, while 4 Ohm is most common for car audio. 6 is about as common as 4 in home theater, and they aren't that hard to find, just not nearly as common as 8 Ohm. All of the Polk LSis are 4 Ohm, for example. I'm in the process of picking up a new set of surrounds, which will make all my speakers 4 Ohm.

    Yes, 8 would most likely be the easiest way to go. If you walk into most big name stores like Best Buy, Circuit City, etc... the majority of their speakers will likely be 8 Ohm.

    4 Ohm speakers drive the amp harder, so the "advantage" is you get more power out of the amp, providing it is 4 Ohm stable to handle that load. You are still driving the amp harder though...
     
  6. SteveMetcalf

    SteveMetcalf Agent

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    Speaker impedance has more to do with how the amp interacts with the speaker than anything. When you see 4,6,8,16 ohm speakers, this is a nominal rating. At different frequencies a speaker has different impedance. For example, an 8 ohm speaker at 100hz could read 50 ohms if checked with the proper meter.
    Certainly a mismatch of impedance is not a good thing, but it will depend on the amp as to how much of a difference you might hear. In tandem with the impedance of a speaker is the slew rate of the amp. The slew rate is a measure of how quickly voltage changes happen over time. Changing the impedance of the speaker varies this, and has subsequent audible results depending on the amp. The way to pick the right combo however, is not found by checking the back of the speaker. As I mentioned before speakers have impedance varying by frequency, if the amp doesn't handle this well, it sounds crappy. If you listen to the same set of speakers on different amps with the same impedance ratings you'll find audible differences in the high and low frequencies(however negligable). These,frequencies incedentally are the two points where a speaker reaches it's highest impedance. You'll find that the amps with the better designed power supply will give you a more even sound since as the demand for voltage changes none of the internal circuits will starve.

    The best thing you can do is take out a cd, go to a store, pick you speakers FIRST since they are more important, and then pair them with an amp that you can afford. As far as sound quality goes speaker dollars are worth more than amp dollars.

    Fequency response is important within the audible range of hearing ONLY! ie:16hz - 25000hz(according to studies typically females are the ones who hear this high, males btwn 19-21000hz)

    It has come to my attentions that certain individuals and companies(who will remain nameless - you know who they are)
    are claiming the benefits of frequency response in excess of 25000hz. DON'T BELEIVE IT! BUNK! Most studio microphones(which capture our music and audio for video)do not respond past 20,22k. Even microphones intended for measurement only top off between 35-50khz. On top of this, digitally recorded music is low pass filtered to eliminate the sampling frequency used as a reference to create a digital file. As for the low frequencies, if your planning on using a sub dont worry about anything below 100hz. Basically, just look for the highest sensitivity rating ([email protected]) and the flattest response curve between 80hz and 20khz. Above all LISTEN. When you try buy speakers focus on what's important theres a lot of misinformation out there.

    Oh Yeah! Make sure your speakers rated wattage is equal to, or less than that of your amp.

    Hope this helps.
     

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