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audio jargon and spec sheet data

Discussion in 'Archived Threads 2001-2004' started by Ted_T, Jul 30, 2001.

  1. Ted_T

    Ted_T Auditioning

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    Hello all again,
    I was doing some research on recievers and speakers and found myself totally lost. So I took some time to try and learn this jargon I kept seeing and trying to find info on how to understand the spec sheet data. I came up with very technical sites but nothing for the laymen.
    I was wondering if any of you have any links or pointers on some info on all the technical side of HT that is done for the laymen like myself.
    A short example of this is I was thinking about the Denon 2802 reciever and it is rated at 90watts,8ohms , 20hz-20khz .05%THD and the speakers I was looking at were the Paradigm S-20s which need a suitable amp power range of 15-150watts and a maximum input power of 100watts. So from my understanding the Denon shouldnt work with those speakers but my friend says they do. He had no more patience to tell me why or how.
    I also need to know the meanings of things like "clip" and what THD is and why lower is better. So as you can see when it comes to audio I am without a doubt the biggest dunce in the entire net. I dont mind doing the leg work myself I just need a direction to go and find this so I can get on my feet.
    Thanx again for your time.
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    Ted
     
  2. Tim Hoover

    Tim Hoover Screenwriter

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    Well, in plain English clipping occurs when you overload a stage in your home theater- be it preamp, power amp, or speakers. It sounds nasty and distorted. THD is Total Harmonic Distortion. The lower that number, the more accurately that piece of equipment can pass a sound without adding its own distortion or coloration. In reference to the speakers you mentioned, they needed 15-150W but a max of 100W? That's a little odd. How can they require up to 150W if the max input is 100W?
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  3. Ted_T

    Ted_T Auditioning

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    Tim H,
    Thanx for the little info on clip and THD. I knew some of THD I just want to know all. Like how does a piece of audio equipment color a sound. I guess what I am looking for is alittle beyond what help anyone would give here. I should have known it is a bit and beyond. =) I will give myself a full 24 hours to do the homework one of these days off.
    Re Speakers:
    I have no idea, I just went to teh paradigm website because I know they come recommended by many HT people. Was reading the data sheets on the studio line and they are all like that. It has a suitable amp power range and a maximum input power listing. I didnt understand hwo they went together and what number I should be concerned about when looking at amps to power these speakers. Which is one of the reasons I came here.
    Thanx again.
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    Ted
     
  4. Saurav

    Saurav Cinematographer

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    quote: I guess what I am looking for is alittle beyond what help anyone would give here. I should have known it is a bit and beyond. =)[/quote]
    What do you want to know, exactly? There are people on here who probably know a lot more technical stuff than you will easily find online. If you ask a generic newbie-level question, you will get a generic newbie-level answer, because no one here wants to confuse and disappoint a beginner by making him feel like he doesn't know anything. So, yes, if you're looking for the basics, go to http://www.google.com
    Anyway, on to your questions:
    quote: I came up with very technical sites but nothing for the laymen.[/quote]
    Like what? Could you post links to some sites that you found to be 'too technical'? That would give us some idea about your level of technical knowledge, which would help us communicate with you in terms that you would understand.
    quote: A short example of this is I was thinking about the Denon 2802 reciever and it is rated at 90watts,8ohms , 20hz-20khz .05%THD and the speakers I was looking at were the Paradigm S-20s which need a suitable amp power range of 15-150watts and a maximum input power of 100watts. So from my understanding the Denon shouldnt work with those speakers but my friend says they do. He had no more patience to tell me why or how.[/quote]
    What combination of numbers in there made you think that this combination shouldn't work? In this case, I think your friend is right - what Paradigm is telling you is that any amp with more than 15 watts per channel will be able to drive these speakers. Your receiver is 90 wpc, so it should drive these more than adequately.
    Here's the background info you're probably looking for: in general, having an amp with a higher power rating than your speakers isn't a problem. This means that the amp will be able to adequately drive the speakers to their limit, i.e., the speakers will reach their point of distortion before the amp does. This is a good thing, because an overdriven amp sending distorted signals into a speaker is much more damaging for the speaker, than overdriving the speaker itself. So, having an more amplifier power than you need is a much better option than having an underpowered amp.
    In your case, my guess is that the remaining numbers (100W and 150W) are telling you this - your speakers can handle momentary peaks of up to 150W from the amplifier, and they can handle a maximum of 100W continuous from an amplifier. So you see, your 90W amp is close to being a perfect match for your speakers - it's powerful enough to drive them almost to their full capacity, but not so powerful that a drunk friend at a party can accidentally turn up the volume to full and end up blowing your speakers.
    Does that answer your question?
    quote: I also need to know the meanings of things like "clip" and what THD is and why lower is better.[/quote]
    As Tim said, clipping is pushing an amp beyond its limits. This sends very distorted signals to the speakers, which are very harmful to them, especially the tweeters. You can permanently damage tweeters this way.
    THD - it's a measure of distortion, so it should be obvious why lower is better - given two amps that can play equally loud, would you prefer the one that faithfully reproduces the original signal, or one which adds lots of its own distortion?
    If you want specifics of how THD is defined and how it's measured, that's more technical than I can help you with. You should be able to find resources on the net for that.
    quote: So as you can see when it comes to audio I am without a doubt the biggest dunce in the entire net.[/quote]
    You're absolutely wrong again [​IMG] The biggest dunces are people who think they know all the answers, and aren't willing to learn something new. You don't strike me as that kind of a person.
    Anyway... hope that was of some help. Also, I hope I didn't upset you or intimidate you, please feel free to ask any questions you have on this forum, that's the reason for the existence of boards like this one.
    Saurav
    [Edited last by Saurav on July 31, 2001 at 01:55 PM]
     
  5. Ted_T

    Ted_T Auditioning

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    Saurav said "Does that answer your question?"
    Yes, I think that is exactly what was confusing me and you explained it very nicely thank you. I didnt see why they had two power ratings listed and what would happen if you were under or over on one of the components (amp vs speakers). So from what you said I think what the relationship is if your amp is underpowered for the speakers the distortion will rise and you wont get as clear a sound, of if it is really underpowered the amp will clip causing more distortion and possible damage? But if the amp is overpowered for the speakers the speakers will just fall off and distort before the amp has a chance to cause distortion.
    Am I understand all that correct or do I still have something confused? OKay I now think I understand the data behind THD the next question what is acceptable? Is this all an ear thing or is there some baseline that anything other is usually okay and anything over is horrible?
    OKay well I am going to grab the altavista bus and see what I can turn up on my own.
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    Ted
     
  6. Ted Lee

    Ted Lee Lead Actor

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    from one ted to another... [​IMG]
    i also highly recommend you subscribe to some a/v magazines. i'd say the majority of what i've learned came from those magazines.
    for someone who is just learning, they are an excellent source to learn the lingo and jargon. most of the middle-of-the-road rags do a pretty good job of explaining technical concepts in laymans terms. A couple examples:
    soundandvision: great mag to learn the technology; entry level stuff that i can actually afford
    stereophile: mid-end and up; more technical in nature
    audio video interiors: just a cool magazine that makes me pissed off that i don't have anything like that! [​IMG]
    also, check out some on-line a/v ezines, they usually have pretty good articles. just a couple examples:
    http://www.cheaphometheater.com/ http://www.hometheatermag.com/ http://www.hometheaterhifi.com/main.html http://www.smr-home-theatre.org/Interface.html
    finally, never be afraid to post something. as you get more experienced, you'll know how to post your questions (heck...i'm still learning myself). you're doing the right thing by asking for other's help & opinions.
    oh...one final thing. above all, trust your own ears. people can tell you all day long about one thing or another, but ultimately, you should trust your ears to help you decide what sounds best.
    hope this helps...
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    But the water has moved on.
    This page is not here.
     
  7. Saurav

    Saurav Cinematographer

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  8. RobertW

    RobertW Supporting Actor

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    according to paradigm, those max power figures are given using a typical program source, providing the amplifier clips no more than 10% of the time.
    an amp clipping ten percent of the time seems a bit much for me, so i assume that given a cleaner power source, one that can generate more power without clipping, the speakers should be able to handle it no problem. hence, the suitable amplifier power range.
    keep in mind, that rarely will you be taxing an amplifier to put out its full output levels, 20 or 30 watts continuous will reach extremely loud volume levels. where that extra amp power comes in is for brief transients(an explosion, kick drum burst, etc.) lasting less than a second, and this short a burst of power shouldn't harm a speaker, providing it isn't just a burst of distortion.
    currently i've got a 205 watts/channel parasound amp powering my studio 20's and everything's fine. although the small apartment prevents me from really turning it up, those extra power reserves help in the bass, as well as just generally providing power effortlessly for my speakers.
     
  9. Ted_T

    Ted_T Auditioning

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    Ted L,
    Thank you for the links, will have to check into those mags you mentioned. Will also follow up on the links you provided. I also ran into the 13 part Audio FAQs which was a real eye opener and a real nice source of the basics.
    Saurav,
    Thanx again for having the patentiece to get me straightened out. That bit about full response vs 1kHz was real nice since I see that all over. I am kicking myself for not liking music because if I had maybe today I wouldnt be so ignorant in the world of sound.
    Rob W,
    Thank you, I read the little link about 10 percent clip I just wasnt of teh understanding then that I am now. I still think it is best to have 0 clip on your amp so I dont know why they would quote 10%.
    Thanx again all
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    Ted
     

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