speakers / sub / amp - ? -

Discussion in 'OT Technology' started by michelin man, Feb 27, 2005.

  1. michelin man

    michelin man IDB Construction

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    i'm looking to get all new stuff for my xterra and i dont have a clue where to start.

    head unit: alpine 9827
    fronts: 6.5 Components
    rear: 6x9
     
  2. Ronin

    Ronin Guest

    MB Quart Speakers are good, also check into CDT, the alpine components work 2. As far the rear dont worry too much, just get some cheaper 6x9s, if you fade the sound more towards your front speakers you wont be able to tell, and who cares about those passengers.

    as far as sub and amp go its hard to tell because i dont have a budget to work with but you really cant lose with an Adire Audio Shiva for 125 bucks. Find a releatively good quality amp around hmm, 300-500 watts should be good, see if you can check the damping factor 2, you want a high damping factor. Also check for low frequency response and distortion ratings.
     
  3. johnson

    johnson New Member

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    Shiva has been out of stock for the past few weeks. The Ascendant Audio Atlas 12" is going for $145 (price just dropped from ~$160) right now and im thinking about ordering it tomorrow w/ a Rythmik Audio 250W plate amp. From what ive read, the price difference is worth it.
     
  4. veonake

    veonake OnT poster, OT lurker

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    Why check the damping factor or low frequency response? Oh, and apparently distortion ratings (I assume you are referring to THD) don't really matter much either when determining if an amp is quality or not.

    Another note, I wouldn't even buy rear speakers if you don't care about the passengers. Just spend more money on the fronts and remove the rears. This also lets you spend more money on a better 2-channel amp, while at the same time getting more power.
     
  5. StealthMode

    StealthMode Active Member

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    When I did my setup I just left the factory rear 6x9's, they sounded fine and were a decent rear fill, if I even used them. So if the rears are in good shape, leave em, get better fronts, with a decent amp and your sub and you'll be set.
     
  6. Ronin

    Ronin Guest

    Damping factor is important if you understand what it does.

    The better the amplifier can provide varying amounts of current without changing the applied voltage to the speaker system, the more accurately the speaker will reproduce what the amplifier is trying to tell it to do.

    The reason that a speaker might require more - or less - current given a particular applied voltage is that the impedance of the speaker system changes depending on what direction the speaker drivers are moving when the voltage is applied, how fast they are moving that way, and where they actually are in the first place.

    The damping factor is the specified load impedance divided by the amplifier's output impedance.


    Low frequency response is important because since it will be driving a subwoofer he will want the amp to be able to handle as low of a note as possible.
     
  7. veonake

    veonake OnT poster, OT lurker

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    He was talking about driving component speakers, obviously I know why low frequency response would be important for a subwoofer :rofl: .

    So are you referring to basically how good the buffer is? Why does the impedance of the load change based on which direction the driver is moving? That doesn't make sense to me, I thought speakers were at a fixed impedance, but I'd like for you to explain why this happens.

    Also, what is considered a good damping factor?
     
  8. Ronin

    Ronin Guest

    the title of the thread is speakers/sub/amp

    when i was talking amp i was referring to a sub amp.

    i am not going to lecture you further on the workings of impedance loads and damping factors and so forth. mostly because i barely understand it myself, and two, itd take typing i do not wish to do.

    Google it, you'll find out all you need, I get like 99% of my knowledge from the internet, so maybe some of what im saying is wrong, i dont mind being proven wrong though because then I learn more.
     
  9. veonake

    veonake OnT poster, OT lurker

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    Ok, I didn't notice the sub part, he didn't even mention it in his post.

    I wasn't asking for a lecture lol, but if you barely understand it then it doesn't make sense to be adament about it. I guess I will do my own research then.

    Edit: After some quick research, you are indeed correct about the damping factor, the higher the better. 100 and above is an excellent number, and once you start dipping towards 20 it is pretty bad. Off to get some in-depth knowledge of it.

    Edit 2: Nice copy and paste from http://www.classic-audio.com/marantz/mdampingfactor.html without any citation btw.
     
    Last edited: Feb 28, 2005
  10. Ronin

    Ronin Guest

    yes because i am so concerned about being in trouble for plagarism/copyright infringement :o
     
  11. veonake

    veonake OnT poster, OT lurker

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    As if I fear for you getting in trouble. I said so because by not at least putting quotations around the information you took, it looks as if you wrote it and knew what you were talking about. It is for the benifit for the reader. I wouldn't have asked you for more information on it, if I knew that you were just quoting someone else.
     
  12. Ronin

    Ronin Guest

    tushe`, point taken.
     
  13. 04

    04 Guest

    All that is true, except the last paragraph. Very few solid state amplifiers cant play flat to 20hz (or lower) with less than 1dB tolerance. That shouldnt be a problem.

    The damping factor on almost all solid state (transistor based) amplifiers these days is high enough that it makes absolutely no difference. It is very easy to model what changes will happen to the sound with a decreased damping factor.

    And even an amp with an excessively high output impedence, will usually have some sort of negative feedback to make the amplifier's frequency response less load impedence variant.

    Long story short. Don't look at the damping factor to compare amplifiers. Even between tube and solid state.
     
    Last edited by a moderator: Feb 28, 2005
  14. 04

    04 Guest

    The impedence of the driver changes based on direction the driver is because reactance is frequency based. Even if you measure a speaker's impedence at every frequency, it will not be single value. It will vary due to the speakers free air resonance, voice coil inductance, and other factors. an 8ohm speaker is simply a speaker that has an 8ohm "average" impedence over its bandwidth.

    In systems where you have high current flow, the voice coil wire will heat up, and increasing temperature increases resistance as well. This means that a speaker that has been playing at full output for 4 hours will have a different impedence than one that has just been pulled out of its packaging. That will also make the value different.

    The speaker when in motion will also have a different impedence based on voice coil position in the magnetic gap because the magnetic field will change when the coil is positioned differently. It's the same reason that the same number of turns in an iron cored inductor has more inductance than an air-cored inductor with the same number of turns.
     
  15. veonake

    veonake OnT poster, OT lurker

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    I should have caught the low frequency thing. Now I feel dumb for conceding that it would matter.

    I thought that increased negative feedback was not necessarily a good thing though. Are you sure that the average amplifier today will have a very good damping factor? I'm sure this is true for anything audiophile or approaching audiophile, but what about something like say Xplod :)x:)?
     
  16. veonake

    veonake OnT poster, OT lurker

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    :hs:
     
  17. veonake

    veonake OnT poster, OT lurker

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    Crap, whole reply written up and it gives me an error page. In summary, I realized why the impedance changes based on driver position, speed, etc. shortly after posting because I remembered from physics how impedance is dependent on frequency, etc. Brings up bad memories from my midterm last week.
     
  18. 04

    04 Guest

    Negative feedback is good or bad determing on who you ask. Yes, just about any car audio amp these days will have an adequate damping factor. This includes cheap amplifiers. I'm sure if you look hard you can find one that's really bad though.
     
  19. Ronin

    Ronin Guest

    like those brands you can only find on Ebay
     
  20. 04

    04 Guest

    Perhaps :o

    Although even flea market brands usually have a high enough damping factor (there are always exceptions though).
     
  21. michelin man

    michelin man IDB Construction

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    as for the 6.5 Components, I have <$200 to spend...?
    MB Quart
    Inifinity
    Polk
    Alpine
    any other ideas?
     

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