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Thread: Questions About Ascend Speaker Measurements

  1. #1
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    Default Questions About Ascend Speaker Measurements

    I was looking at the Specifications page for the Sierra 2 speakers and it mentions that the maximum continuous power is 150 Watts and the maximum short term peak power is 300 Watts. I understand what this is saying but I am a little confused about the "Unclipped peaks" that are mentioned in the asterisk.

    I'm not sure if this is a warning that they can only accept this amount of power safely if it is clean in terms of THD less than say 0.01% for the 150 Watts delivered continuously and say less than 1% THD for short term peaks of 300 Watts. Or is this is saying that in the case that you are cleanly delivering 150 Watts continuously and up to 300 Watts in short term peaks, that the speaker is playing cleanly, in other words with low THD + noise.

    So, I guess I will ask my question. Say that I have an amplifier that can deliver 150 W continuously with THD less than 0.01% and short term peaks of 300 W at less than 1% THD. Will the Sierra 2s produce an output that has low THD + noise (in the low single digits) when it is pushed close to these limits?

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    Default Re: Questions About Ascend Speaker Measurements

    I think it just means they won't blow up with that kind of power.
    -curtis

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    Default Re: Questions About Ascend Speaker Measurements

    Quote Originally Posted by N Boros View Post
    I was looking at the Specifications page for the Sierra 2 speakers and it mentions that the maximum continuous power is 150 Watts and the maximum short term peak power is 300 Watts. I understand what this is saying but I am a little confused about the "Unclipped peaks" that are mentioned in the asterisk.

    I'm not sure if this is a warning that they can only accept this amount of power safely if it is clean in terms of THD less than say 0.01% for the 150 Watts delivered continuously and say less than 1% THD for short term peaks of 300 Watts. Or is this is saying that in the case that you are cleanly delivering 150 Watts continuously and up to 300 Watts in short term peaks, that the speaker is playing cleanly, in other words with low THD + noise.

    So, I guess I will ask my question. Say that I have an amplifier that can deliver 150 W continuously with THD less than 0.01% and short term peaks of 300 W at less than 1% THD. Will the Sierra 2s produce an output that has low THD + noise (in the low single digits) when it is pushed close to these limits?
    I am sorry but I don't follow your question. The power spec for the Sierra-2 has nothing to do with amplifier THD. If an amplifier clips it produces a distorted square wave which even at low power can destroy speaker components. Clipping distortion is a combination of many different types of distortion, it also produces odd order harmonics that are not part of the source material -- these harmonics can cause components to quickly over heat. Amplifier specifications really do not give any insight as to how the amplifier will behave when it clips, or when it will start clipping as there are far too many variables involved.
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    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

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    Default Re: Questions About Ascend Speaker Measurements

    Quote Originally Posted by davef View Post
    I am sorry but I don't follow your question. The power spec for the Sierra-2 has nothing to do with amplifier THD. If an amplifier clips it produces a distorted square wave which even at low power can destroy speaker components. Clipping distortion is a combination of many different types of distortion, it also produces odd order harmonics that are not part of the source material -- these harmonics can cause components to quickly over heat. Amplifier specifications really do not give any insight as to how the amplifier will behave when it clips, or when it will start clipping as there are far too many variables involved.
    Okay so the "unclipped peaks" is not referring to the amplifier. So it must be referring to the output of the speaker when one is driving it near the limits of 150 W continuously and with 300 W peaks. Just doing some rough calculations at my seating distance of 10 feet away, to hit 105 dB peaks for reference volume, the Sierra 2s need about 300 W.

    In the Sierra Sat thread you mention that the Sats can hit about 99 dB peaks at about 10 feet away without any compression to your ears. So will the Sierra 2s be able to hit 105 dB peaks cleanly (without high distortion or compression)? It this what you are referring to my "unclipped peaks"?

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    Default Re: Questions About Ascend Speaker Measurements

    Quote Originally Posted by N Boros View Post
    Okay so the "unclipped peaks" is not referring to the amplifier. So it must be referring to the output of the speaker when one is driving it near the limits of 150 W continuously and with 300 W peaks. Just doing some rough calculations at my seating distance of 10 feet away, to hit 105 dB peaks for reference volume, the Sierra 2s need about 300 W.

    In the Sierra Sat thread you mention that the Sats can hit about 99 dB peaks at about 10 feet away without any compression to your ears. So will the Sierra 2s be able to hit 105 dB peaks cleanly (without high distortion or compression)? It this what you are referring to my "unclipped peaks"?
    Unclipped peaks just refers to music that has big, loud passages which do not clip, IE they don't go above 0 dB. In these loudness wars between label companies there have been some releases that contain clipped signals and this can wreak havoc on a good system. I very rarely run into it with music, though.

    105 dB seems pretty intense, though. I don't know why you want to run your speakers that loud, but I don't see why the Sierra 2 wouldn't be able to handle it. I play my Sierra towers pretty loud and they have not lost composure on me even once. I power them with an Emotiva XPA-5 Gen 2 so they get a decent amount of juice, 300 watts into 2 channels or 200 into 5. I can tell you that I have never, ever given them the full juice they can take. It'll melt your ears off your head with how loud it'll get.
    -Alex
    PS4/Nvidia Shield --> Emotiva XMC-1 --> Emotiva XPA-5 --> Ascend Acoustics Sierra Towers and Horizon Center w/ RAAL tweeters (L/C/R), HTM-200 SE (Surrounds), 2x Rythmik F12 subwoofers

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    Exclamation Re: Questions About Ascend Speaker Measurements

    NB,

    I apologize if my comments below are already understood, but thought I'd put this out there for members that may still have some questions relating to amplifier power needs versus transducer ratings.

    In the real world, audio music\soundtrack playback can\does generate up to +10db of dynamic headroom peaks. In the case of the Sierra 2's, if your playback levels are averaging 87db with 1 watt of power, then you will need 10 watts of clean power to safely cover the musical peaks (logarithmic facts state 10db=10X power). Thus you need an amp that has a "clean 10 watts of power output"! In this scenario, the dynamic musical waveforms are smooth and unclipped with S2 playback that has natural and clean dynamics as per the genre of music.

    Continuing with the Sierra 2's (in the real world), their maximum continuous unclipped power rating of 150 watts means that your sustained maximum S2 playback levels will only handle "15 continuous watts" of amplifier power, which still yields 150 watts of unclipped, clean dynamic musical peaks! At this point if your power amp has a clean continuous power output per channel of 150 watts, the theoretical musical output of the S2's would be 98.5 db, with 108.5 db of CLEAN, UNDISTORTED Musical Peaks...all is good!!!

    Dave also rates the S2's as being able to handle maximum short term peak power of 300 watts. Assuming your amp is rated for continuous clean 300 watts per channel, then the S2's could (during short duration playback levels), give clean dynamic peaks of 111.5db!!

    As Dave has clearly stated, amplifiers pushed past their clean power ratings, [such as when attempting to cover the +10db of headroom to cover real-world musical peaks], DO go into extreme waveform clipping distortions, generating tremendous heat in the driver voice coils that quickly can destroy the speakers. I've seen it happen in tweeters and woofers...Not Pretty!

    If music playback starts to sound harsh, strained or fatiguing, probably a good indication that the amp is being driven into dynamic peak distortions...turn it down or you may end up needing to replace drivers!

    Again "in-the-real-world", driving speakers with low powered amps can quickly create a Much Greater Risk of damaging (blowing) speaker drivers due to entering into clipping amplifier waveforms while attempting louder playback levels. Matching, or slightly exceeding the max clean power rating of the amp to the speaker rating goes a long way to enjoying your HT or Stereo for a much longer time. Either way, still be cautious of maintaining "Clean Amplifier Peak" playback levels!

    Hope this was clear and possibly helpful,

    Ted
    Last edited by theophile; 11-01-2016 at 08:51 AM.
    Sierra RAAL V2 Towers, Axiom EP 500 Sub, Morrow SP7 Grand Reference Speaker Cables, Phillips CD880 XLR Balanced Variable Line Output to Orchard Audio Strakrimson 375w/per ch Stereo Ultra GaNFET Amp..... (Dedicated 2.1 Acoustical Music Listening Room)!

  7. #7
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    Default Re: Questions About Ascend Speaker Measurements

    Extremely well written post there, theophile! Thanks for explaining it so well. Much better job than I could ever do.

    You have to agree with using an amp that covers every situation with plenty of power. Many people end up damaging their speakers simply by driving them too hard with crappy receivers.
    -Alex
    PS4/Nvidia Shield --> Emotiva XMC-1 --> Emotiva XPA-5 --> Ascend Acoustics Sierra Towers and Horizon Center w/ RAAL tweeters (L/C/R), HTM-200 SE (Surrounds), 2x Rythmik F12 subwoofers

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    Smile Re: Questions About Ascend Speaker Measurements

    Quote Originally Posted by sludgeogre View Post
    Extremely well written post there, theophile! Thanks for explaining it so well. Much better job than I could ever do.

    You have to agree with using an amp that covers every situation with plenty of power. Many people end up damaging their speakers simply by driving them too hard with crappy receivers.
    Thanks Alex!

    Plenty of "Clean Power" is almost Never a problem. Over driving an amplifier, usually because it is under-powered for the intended musical use (being a receiver or a stand-alone high quality power amp=no difference) is suspect 99% of the time with damaged drivers! Low clean power (<50 watts)...be very cautious of volume playback. High clean power (>100watts), Enjoy the Music!!

    Ted
    Sierra RAAL V2 Towers, Axiom EP 500 Sub, Morrow SP7 Grand Reference Speaker Cables, Phillips CD880 XLR Balanced Variable Line Output to Orchard Audio Strakrimson 375w/per ch Stereo Ultra GaNFET Amp..... (Dedicated 2.1 Acoustical Music Listening Room)!

  9. #9
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    Default Re: Questions About Ascend Speaker Measurements

    Quote Originally Posted by theophile View Post
    Thanks Alex!

    Plenty of "Clean Power" is almost Never a problem. Over driving an amplifier, usually because it is under-powered for the intended musical use (being a receiver or a stand-alone high quality power amp=no difference) is suspect 99% of the time with damaged drivers! Low clean power (<50 watts)...be very cautious of volume playback. High clean power (>100watts), Enjoy the Music!!

    Ted
    Absolutely, clean power is the key. Indeed it doesn't matter if it's separates or a receiver, it just seems like those cheap class D sections in low-tier receivers seem to be the culprit most of the time. I know the only time I've ever blown a speaker was with one of those. I could also see people doing it with those awful little Tripath amps that you can get for like 30 bucks, wow do those sound distorted when you push them. Personally I've been going back and forth on whether I want to upgrade to an Emotiva XMC-1 and another amp for Atmos or just go with an Anthem receiver... decisions, decisions... Won't be for a couple years anyway.
    -Alex
    PS4/Nvidia Shield --> Emotiva XMC-1 --> Emotiva XPA-5 --> Ascend Acoustics Sierra Towers and Horizon Center w/ RAAL tweeters (L/C/R), HTM-200 SE (Surrounds), 2x Rythmik F12 subwoofers

  10. #10
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    Default Re: Questions About Ascend Speaker Measurements

    Quote Originally Posted by theophile View Post
    NB,

    I apologize if my comments below are already understood, but thought I'd put this out there for members that may still have some questions relating to amplifier power needs versus transducer ratings.

    In the real world, audio music\soundtrack playback can\does generate up to +10db of dynamic headroom peaks. In the case of the Sierra 2's, if your playback levels are averaging 87db with 1 watt of power, then you will need 10 watts of clean power to safely cover the musical peaks (logarithmic facts state 10db=10X power). Thus you need an amp that has a "clean 10 watts of power output"! In this scenario, the dynamic musical waveforms are smooth and unclipped with S2 playback that has natural and clean dynamics as per the genre of music.

    Continuing with the Sierra 2's (in the real world), their maximum continuous unclipped power rating of 150 watts means that your sustained maximum S2 playback levels will only handle "15 continuous watts" of amplifier power, which still yields 150 watts of unclipped, clean dynamic musical peaks! At this point if your power amp has a clean continuous power output per channel of 150 watts, the theoretical musical output of the S2's would be 98.5 db, with 108.5 db of CLEAN, UNDISTORTED Musical Peaks...all is good!!!

    Dave also rates the S2's as being able to handle maximum short term peak power of 300 watts. Assuming your amp is rated for continuous clean 300 watts per channel, then the S2's could (during short duration playback levels), give clean dynamic peaks of 111.5db!!

    As Dave has clearly stated, amplifiers pushed past their clean power ratings, [such as when attempting to cover the +10db of headroom to cover real-world musical peaks], DO go into extreme waveform clipping distortions, generating tremendous heat in the driver voice coils that quickly can destroy the speakers. I've seen it happen in tweeters and woofers...Not Pretty!

    If music playback starts to sound harsh, strained or fatiguing, probably a good indication that the amp is being driven into dynamic peak distortions...turn it down or you may end up needing to replace drivers!

    Again "in-the-real-world", driving speakers with low powered amps can quickly create a Much Greater Risk of damaging (blowing) speaker drivers due to entering into clipping amplifier waveforms while attempting louder playback levels. Matching, or slightly exceeding the max clean power rating of the amp to the speaker rating goes a long way to enjoying your HT or Stereo for a much longer time. Either way, still be cautious of maintaining "Clean Amplifier Peak" playback levels!

    Hope this was clear and possibly helpful,

    Ted
    Hi Ted,

    Thanks for this explaination. This is helpful to me and others.

    I did want to make just one small correction and expand on this a bit. To add 10dB of output we need to multiple the amplifer power by 10. That is correct. Also, if we want to vary the distance from the sensitivity spec, where it was measured at 1 meter away from the speaker we need to subtract about 3dB (in a room) for every doubling of the distance. Or to get a 3 dB gain we need to double the power. With these three things in mind we can take the sensitivity and figure out how loud the speakers can get in our seat.

    One small correction on the sensitivity though. Since this is a nominal 6 ohm speaker it is actually 1.33 Watts to produce 87 dB at 1 m away from the speaker.

    Double the distance: 1.33 W gives 84 dB at 2m
    10 times power: 13.3 W gives 94 dB at 2m
    10 times power: 133 W gives 104 dB at 2m
    Double the distance: 266 W gives 104 dB at 4m

    My main seating area is only about 3 meters away from the speakers, but I will have a second row at about 5 meters away. My main concern is to be able to hit reference volume for movies, which is 85 dB average and up to 105 dB peaks. That is the loudest I would ever crank up an action movie and this would be a rare occurrence. But, I just want to make sure that I can cleanly hit it and maybe set the volume limiter in the receiver or processor at this level. So if I calculated this correctly I guess that this is not problem. I just need to get an amplifier that can cleanly put out 250 W to 300 W peaks.

    Back to my original question. If our amplifier can cleanly put out 300 W peaks, is the output from the speaker still clean at those 300 Watt peaks (Note that a 105 dB peak will be very close to needing 300 Watts at 4m away.)? Or would we be hearing distortion or compression when the speaker is driven with that amount of power?
    Last edited by N Boros; 11-01-2016 at 01:05 PM.

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