Results 1 to 14 of 14

Thread: watts

  1. #1
    Forum Regular
    Join Date
    Nov 2004
    Posts
    39

    watts

    I have a question about watts. Obviously the higher the watts the more power you are getting and in the learn section of this website I found this "For real surround sound like what you hear in the theater buy a receiver with 80 watts per channel. Good receivers deliver this kind of power to each of the front speaker channels. Great receivers deliver this kind of power to all the speaker channels."
    I have seen some discussion in various threads about some companies "beefing" up this stat on their receivers. I am looking at H/K receivers and they typically have a lower watt rating than every other company in their league, but have seen some people say that they still have as much power as some of these other receivers rated at say 100 watts.
    My question I guess is this, is a 70w receiver from H/K going to cut it?

  2. #2
    Digs tunes and vids RJW1138's Avatar
    Join Date
    Sep 2004
    Location
    Regina, SK
    Posts
    46
    Quote Originally Posted by spuppy517
    I have a question about watts. Obviously the higher the watts the more power you are getting and in the learn section of this website I found this "For real surround sound — like what you hear in the theater — buy a receiver with 80 watts per channel. Good receivers deliver this kind of power to each of the front speaker channels. Great receivers deliver this kind of power to all the speaker channels."
    I have seen some discussion in various threads about some companies "beefing" up this stat on their receivers. I am looking at H/K receivers and they typically have a lower watt rating than every other company in their league, but have seen some people say that they still have as much power as some of these other receivers rated at say 100 watts.
    My question I guess is this, is a 70w receiver from H/K going to cut it?
    Power is meaningless on its own. It only has meaning in the context of the sensitivity ratings of your speakers. Is 70wpc enough for 82 dB sensitive speakers? Probably not. Is it enough for 90 dB speakers? Probably, but it depends on how loud you want to go. Knowing the RMS per-channel power of your receiver will tell you how many dB of gain you can get above the 1 W sensitivity rating of your speaker. You can do the simple math yourself.

    H/K rates their receivers with actual power ratings, as does NAD and several other companies. The other mass-market brands are always inflated. The real value you want to know is RMS power per channel, 20 - 20000 Hz, all channels driven. Any other type of measurement will be inflated, and appear larger.

    Hope this helps.

  3. #3
    Forum Regular
    Join Date
    Dec 2001
    Posts
    553
    Quote Originally Posted by spuppy517
    I have a question about watts. Obviously the higher the watts the more power you are getting and in the learn section of this website I found this "For real surround sound ? like what you hear in the theater ? buy a receiver with 80 watts per channel. Good receivers deliver this kind of power to each of the front speaker channels. Great receivers deliver this kind of power to all the speaker channels."
    I have seen some discussion in various threads about some companies "beefing" up this stat on their receivers. I am looking at H/K receivers and they typically have a lower watt rating than every other company in their league, but have seen some people say that they still have as much power as some of these other receivers rated at say 100 watts.
    My question I guess is this, is a 70w receiver from H/K going to cut it?
    You are in dire need of some enlightenment here, and unfortunately you didn't get it from the "learn" section here which is chockfull of misleading info. Here's a very brief primer on what you need to know and understand:

    RJW touched upon it in his response to you, but didn't take it quite far enough IMO. The "sensitivity" rating of a given speaker (i.e. 87db or 90db or 82db or 95db, etc.) tells you just how loud a sound will be produced (perceived) by the speaker when driven by ONE watt, and heard "on-axis" (directly in front of - not off to one side) and at a distance of 1 meter (approx. 39 in.). All of these loudness numbers are fairly loud, and represent the sound levels that are most common among listeners to most types of music. In other words, most people listen to sounds being generated by about 1 watt of power most of the time. A doubling of the power supplied will generate an increase in loudness of only 3db (a noticeable difference, but not dramatic).

    From the preceding you can easily see the folly of stating that 70, 80, 90, 100 watts or more of power are necessary in any but the most extraordinary of situations. For a speaker with a rating of 90db for example, 1 watt of power produces a sound pressure level of 90db. Doubling of the power to 2 watts produces a loudness of 93db. Doubling again to 4 watts gives 96db ... 8 watts gives 99db ... 16 watts gives 102db ... 32 watts gives 105db ... 64 watts raises the level to 108db, which is approaching a level most people would experience as pain, and very definitely damaging to one's hearing.

    There are other factors involved - such as room size and shape and listening distance from the speaker(s) and the type of furniture, walls, floor coverings, etc. but the overall emphasis on amplifier power is sorely misguided, misunderstood, and misrepresented - often unknowingly - by those presenting such info as "facts" about audio.

    Hope this has helped your understanding some.
    woodman

    I plan to live forever ..... so far, so good!
    Steven Wright

  4. #4
    Digs tunes and vids RJW1138's Avatar
    Join Date
    Sep 2004
    Location
    Regina, SK
    Posts
    46
    Quote Originally Posted by woodman
    You are in dire need of some enlightenment here, and unfortunately you didn't get it from the "learn" section here which is chockfull of misleading info. Here's a very brief primer on what you need to know and understand:

    RJW touched upon it in his response to you, but didn't take it quite far enough IMO. The "sensitivity" rating of a given speaker (i.e. 87db or 90db or 82db or 95db, etc.) tells you just how loud a sound will be produced (perceived) by the speaker when driven by ONE watt, and heard "on-axis" (directly in front of - not off to one side) and at a distance of 1 meter (approx. 39 in.). All of these loudness numbers are fairly loud, and represent the sound levels that are most common among listeners to most types of music. In other words, most people listen to sounds being generated by about 1 watt of power most of the time. A doubling of the power supplied will generate an increase in loudness of only 3db (a noticeable difference, but not dramatic).

    From the preceding you can easily see the folly of stating that 70, 80, 90, 100 watts or more of power are necessary in any but the most extraordinary of situations. For a speaker with a rating of 90db for example, 1 watt of power produces a sound pressure level of 90db. Doubling of the power to 2 watts produces a loudness of 93db. Doubling again to 4 watts gives 96db ... 8 watts gives 99db ... 16 watts gives 102db ... 32 watts gives 105db ... 64 watts raises the level to 108db, which is approaching a level most people would experience as pain, and very definitely damaging to one's hearing.

    There are other factors involved - such as room size and shape and listening distance from the speaker(s) and the type of furniture, walls, floor coverings, etc. but the overall emphasis on amplifier power is sorely misguided, misunderstood, and misrepresented - often unknowingly - by those presenting such info as "facts" about audio.

    Hope this has helped your understanding some.
    You're right, I didn't take it far enough. I was being lazy, and thought I said just enough to get the OP to be motivated enough to go ahead and find out the truth for himself. But, it would've been more useful if I'd actually provided the facts myself, so here it goes.

    The power difference in dB between two power levels is 10 x log (P2 / P1). If you want to know how many dB of gain you get above 1 W, then the formula is 10 x log (P2 / 1), or just 10 x log (P2). As you can see, 10 x log (2/1) = 3.01, and like Woodman said, every doubling of power gives you an extra 3 dB.

    For a real 70W RMS then, the amount of gain is 10 x log (70) = 18.5 dB.

    Now, you take your speaker's 1 W sensitivity at 1 metre, say 90 dB, and add 18.5 db, and you have 108.5 dB SPL with a 70W input at 1 m.

    Now there's 2 more basic factors to consider. The 1st is that when you double the distance, you reduce the SPL by 6 dB. Since 2 m is a typical listening distance, then you'll need to subtract 6 dB from the previous number to get the SPL at the listening position. The 2nd thing is that doubling the number of speakers results in a 3 dB gain. Of course there are other factors as well, but these alone will get you very close to the proper SPL values.

    So, in our example, if we have a stereo pair of 90 dB (1 W,1 m) sensitive speakers, and feed them each a 70 W RMS signal, and sit 2 m from each of them, then our resulting SPL at the listening position is 90 dB + 18.5 dB - 6 dB + 3 dB = 105.5 dB. This is pretty frickin loud.

    Like Woodman said, most of your listening is done with a watt or two (provided your speakers are reasonably sensitive), and NOT with 70 or 100 W.

    However, having extra power never hurts. Amplifiers are generally rated right at the point before their distortion figures start getting very ugly. A 70 W amplifier will be able to provide more than 70 W, but its distortion figures will go from being nice and low (ex: 0.01 % @ 70 W), to high and horrifying (ex: 10% @ 80 W) when past this level. Because of this, you never want to have to exceed the power rating of your amplifier.

    Now in the case of our example, 105.5 dB is very loud, and your average listening level will never approach this. However, say you're watching a movie, and some dynamic content (imagine a gigantic explosion that rocks your room) exceeds the average level by 25 dB (an extreme but not impossible example). If your average listening level was 85 dB (0.8 W, in our example), and this peak hits and requires an extra 25 dB, bringing the SPL up to 110 dB, then you can see that you've far exceeded the clean power abilities of your amplifier. You'd need about 200 W to support this request. This dynamic peak in the sound will thus end up pushing your amplifier into the realm of insane distortion and clipping. In the best case, your ears will rebel and complain and you'll reach for the remote and turn down the volume. You won't be able to enjoy that peak as it was intended. In the worst case, you'll blow your speakers from the clipping amplifier, and that's not much fun. You do not ever want either of these scenarios, and this is why extra power can be a very good thing.

    So then, on average sensitivity speakers, extra power allows you to either listen at insane average levels (while destroying your hearing...), or to have lots of headroom for clean playback of dynamic peaks. But that extra power is NOT tapped when you do not require the extra SPL. If your plans are just to listen to music and watch movies at average, enjoyable levels, then a few watts are really all that you need. You must consider what your intentions are when considering your power needs.

    And of course, in case this isn't clear by now, high power is required just to get moderate listening levels if you have inefficient speakers.

    So there ya go, Spuppy517, you should be an expert at this now. :-)

  5. #5
    Loving This kexodusc's Avatar
    Join Date
    Nov 2003
    Location
    Department of Heuristics and Research on Material Applications
    Posts
    9,025
    Well done guys, we should add this to the "Learn" section!!!

    I would add a few points. 25 dB peaks in movies probably never happens, I dont' think any DD or DTS studio mix would allow that, even good amps would struggle with this. I remember reading somewhere that most loud peaks are usually in the 12 to 15 dB range...that's a good spike.

    Spuppy517...did you know that to double the loudness, you need about 10 times the number of watts? As in 100 watts is only twice as loud as 10 watts of current? More fun with logarithms

    Most crappy mass market receivers (whatever mass market means, NAD and H/K are mass market too, just at lower volumes) will have instantaneous peak power capabilities above their power ratings that they can deliver for peaks.

    http://www.geocities.com/Area51/Holl...1/ratevsac.htm

    This link shows some "real power ratings" with all 5 or 6 or 7 channels driven...Notice how the entry level, base model 75 wpc Yamaha's, for example, will still deliver over 30 WPC to all 6 channels simultaneously. That's still pretty freakin loud and more than enough power for most people, especially considering the efficiency of the speakers that most buyers of these receivers would own.

    As you move up the ladder, ya gets even more.

    Now look at some of the Kenwoods, or Sonys...there's more of a stretch from stated specs to actual ratings.

    In your case, a 70 wpc H/K is probably going to be absolutely fine, especially if it really pumps out 74 watts to all 5 channels simultaneously. Just hope you have better luck with yours than I had with mine.

  6. #6
    Kursun
    Join Date
    Nov 2003
    Location
    Izmir, Turkey
    Posts
    145
    An interesting link, thank you.
    But you have to admit there is more to choosing a complicated electronic component than just comparing how it meets its power spec...

  7. #7
    Digs tunes and vids RJW1138's Avatar
    Join Date
    Sep 2004
    Location
    Regina, SK
    Posts
    46
    Quote Originally Posted by kexodusc
    Well done guys, we should add this to the "Learn" section!!!

    I would add a few points. 25 dB peaks in movies probably never happens, I dont' think any DD or DTS studio mix would allow that, even good amps would struggle with this. I remember reading somewhere that most loud peaks are usually in the 12 to 15 dB range...that's a good spike.

    Spuppy517...did you know that to double the loudness, you need about 10 times the number of watts? As in 100 watts is only twice as loud as 10 watts of current? More fun with logarithms

    Most crappy mass market receivers (whatever mass market means, NAD and H/K are mass market too, just at lower volumes) will have instantaneous peak power capabilities above their power ratings that they can deliver for peaks.

    http://www.geocities.com/Area51/Holl...1/ratevsac.htm

    This link shows some "real power ratings" with all 5 or 6 or 7 channels driven...Notice how the entry level, base model 75 wpc Yamaha's, for example, will still deliver over 30 WPC to all 6 channels simultaneously. That's still pretty freakin loud and more than enough power for most people, especially considering the efficiency of the speakers that most buyers of these receivers would own.

    As you move up the ladder, ya gets even more.

    Now look at some of the Kenwoods, or Sonys...there's more of a stretch from stated specs to actual ratings.

    In your case, a 70 wpc H/K is probably going to be absolutely fine, especially if it really pumps out 74 watts to all 5 channels simultaneously. Just hope you have better luck with yours than I had with mine.
    Yeah, you're right, a peak that large probably isn't possible. Oh well, nothing like a bit of exaggeration to make a point! But yeah, my point: you only need a few watts to make decent SPL, but you need a LOT more to get a few more dB. Ah, the magic of exponents...

  8. #8
    Loving This kexodusc's Avatar
    Join Date
    Nov 2003
    Location
    Department of Heuristics and Research on Material Applications
    Posts
    9,025
    Quote Originally Posted by Kursun
    An interesting link, thank you.
    But you have to admit there is more to choosing a complicated electronic component than just comparing how it meets its power spec...
    Care to elaborate? Nobody here even hinted at anything otherwise, though I'm not sure I'd call an amplifier terribly complicated.,..just provided some info indirect response to a question about a power spec. I don't think anybody here believes the goal is to have as much power as you can get though...I'd always take enough power and better sound/quality over more than enough power and inferior sound. (but then you have to decide how much power is enough )

  9. #9
    Forum Regular
    Join Date
    Nov 2004
    Posts
    39

    woah.....

    Ok - have to admit, most of that was a little over my head but I believe I get the gist.
    So - I also need to pick my speakers according to wpc of my reciever?
    I have discovered that I know absolutely nothing when it comes to speakers, so I guess I'll have research this more. Right now I am only using a crappy out-of the-box Aiwa surround system and have been wanting to upgrade everything for a while now and my subwoofer died so I figured now was a good time to start.
    Kexodusc..... you said "Just hope you have better luck with yours than I had with mine."
    Did you have a bad experience with H/K's???

  10. #10
    Loving This kexodusc's Avatar
    Join Date
    Nov 2003
    Location
    Department of Heuristics and Research on Material Applications
    Posts
    9,025
    I had a few issues with my old H/K receiver, but I honestly believe they've resolved those shut-off features, as you don't sear near as many complaints as you did a few years back (1999/2000). I wouldn't hesitate to recommend H/K.

    You don't need to match speaker watts to amplifier watts. Watt ratings on speakers is almost meaningless. Pay more attention to the Ohms. If the speakers you're looking at are 6 or 8 ohms, you're in the clear. If it's 4 ohms, you'll need a beefy power supply...H/K's typically don't have much problem driving 4 ohm loads, so you're okay there too. Chances are you're speakers will be rated 8 ohms nominal...that's relatively easy to power.

  11. #11
    Suspended markw's Avatar
    Join Date
    Dec 2001
    Location
    Noo Joisey. Youse got a problem wit dat?
    Posts
    4,659
    Ideally, you should choose yourspeakers first and then choose a receiver/amp that can adequately drive them. The speakers are the determining factor on what your setup wil lsound like. The amp/reveiver has far less of an impact on the sound of the system, assuming they provide adequate power to drive the speakers.

    Focus on speaker sensitivity for more on this.

  12. #12
    Forum Regular
    Join Date
    Nov 2004
    Posts
    39

    ok then...

    I guess the next logical question is, any recommendations for speakers?
    There is a pretty good store near me and the recommended Klipsch and Paradigm. I listened to both and thought the both sounded pretty damn good. Any thoughts on those brands or any other suggestions?

  13. #13
    Suspended topspeed's Avatar
    Join Date
    Jun 2003
    Location
    California
    Posts
    3,717
    Speakers are the most subjective of all audio components so believe only your ears and not someone's opinion. One thing about Klipsch is they are supremely efficient and you won't need a whole lot of power to drive them to deafening levels. Paradigms are also an easy drive, although not as sensitive as the Klipsch's. Obviously, you realize that the store near you recommended these two brands because this is what they sell, right? Surprise, surprise!

    Here's what I would do:
    First, set a budget.
    Second, reconcile with the fact that this could take a bit of time.
    Third, grab some of your favorite tunes and go listen to as many speakers as you can find. Listen to different types as well as manufacturers. Find some Magnapans and Martin Logans to see if you like planars and/or 'stats. Listen to some time and phase aligned speakers like Thiel or Vandersteen. There are transmission line style, line array, hybrids, etc. I think you get my point. There are more to the differences in speaker design than simply the label on the front of the enclosure.

    The brands that are most mentioned around here besides the ones you've mentioned are B&W, JM Lab, Boston, Maggie, Audio Note, DefTech, Gallo, Mission, Wharfedale, Bose, Polk, Infinity, Athena, and Von Schweikert (not really on that last one, but I'm biased ).

    Remember, a good pair of speakers can last you a lifetime so take your time. Good luck and enjoy the ride.

  14. #14
    Forum Regular
    Join Date
    Nov 2004
    Posts
    39
    I already know that this speaker deal is going to take some time, I am definitely willing to wait. I am not going to be able to buy all the speakers at once anyway.... I need to upgrade all 5 and get a sub as well as getting a new receiver, so this will be an ongoing work in progress
    I would LOVE to get to listen to all these speakers that you mentioned.... I'm just not sure where to go. I live in Maine so I'm not exactly living in hi tech mecca! The store I mentioned also sells Def Tech, Energy, Monsoon and Vandersteen.... there is a tweeter here but I've never been in so I don't know what kinda stuff they carry.
    I'll figure it all out eventually..... like you said, let my ears decide. Thanks so much.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Too many watts for old JBL L100s?
    By bullseyekp in forum Speakers
    Replies: 7
    Last Post: 12-02-2004, 07:54 PM
  2. Dumb amp/preamp question?
    By Number9 in forum Amps/Preamps
    Replies: 16
    Last Post: 11-27-2004, 07:57 PM
  3. Poll: Which AV Receiver is more value for the $$$ ?
    By thereal_1_ in forum General Audio
    Replies: 8
    Last Post: 11-27-2004, 01:41 PM
  4. How do I measure watts coming out of amp?
    By KRiTiKaL in forum The Audio Lab, Tweaks, Mods, DIY
    Replies: 7
    Last Post: 07-17-2004, 02:35 PM
  5. 400 watts for Studio 100?
    By ARAM in forum Speakers
    Replies: 9
    Last Post: 12-22-2003, 06:30 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •