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  1. #1
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    receiver clipping

    My receiver has volume increaments such as these: (starting @ "-85dB, then -84dB, -83dB...etc. all the way up too "0dB".
    I am wondering whether or not it starts "clipping" before I reach the maximum volume @ "0dB". Is this so? if so, at about which increament? (approx. -10dB perhaps?)
    More importantly, is it giving out its full 100W@6ohms potential at "0dB" or does it deliver it before? Thanks again.

  2. #2
    Audiophile Wireworm5's Avatar
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    I'm no expert, but guarenteed it will clip before you reach full power. My power amp rated for 160 watts will clip at 75 watts according to their test sheet. At 75 watts the db level should be around 116 dbs. I think this is a good benchmark, half of whatever your power rating is, so 100 watts would be 50 watts of clean power. Where that is on your volume knob I have no idea, but I think you can easily crank it to 95 db 'C' weighted and be okay as far as clipping goes.

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    Quote Originally Posted by Wireworm5
    I'm no expert, but guarenteed it will clip before you reach full power. My power amp rated for 160 watts will clip at 75 watts according to their test sheet. At 75 watts the db level should be around 116 dbs. I think this is a good benchmark, half of whatever your power rating is, so 100 watts would be 50 watts of clean power. Where that is on your volume knob I have no idea, but I think you can easily crank it to 95 db 'C' weighted and be okay as far as clipping goes.
    Your Studio 20 v3s sensitivity is (87dB/W/m), impedance (8 Ohms). While that is not horrible, it is not great. With 64 watts of clean power they should be putting out (105 dB/W/m) each, negating any room gain for the pair (108dB/W/m) at 128watts. If his speakers were rated at (102 dB/W/m) like Klipsch Khorns are rated, the same 64 watts of power would be (120dB/W/m) or about the same as a jet engine at take off power each, again negating any room gain for the pair. On the other hand if they were rated at (68 dB/W/m) they would only produce 86 (dB/W/m) negating any gain for the pair. So you see, you cannot base net volume in dB with watts.

    Different amps are built with different quality components and to different design specs so again differences cannot be carried from one unit to another. To know for sure, the only way I know to find out at what “number” the amp clips at is to hook it up to a scope and test it. Again though the results will change with different input devices. If the CD player puts out more voltage than the Turn Tables pre-amp (quite likely) then the amp will clip sooner on the number scale with the CD over the Turn Table.

    In the real world, the number scale is only a reference for you to be able to return to a setting you like. When the receiver was made, I beleave (I could be wrong here) it was balanced in theory to be at full power at 0 but what load was used for testing? Was it a resistor or a speaker? Speakers have an ever-changing load presented to the amp so the results will change a lot between a resistor and a speaker playing music or even a test tone for that matter.

  4. #4
    Loving This kexodusc's Avatar
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    Good questions!

    Quote Originally Posted by Wireworm5
    I'm no expert, but guarenteed it will clip before you reach full power. My power amp rated for 160 watts will clip at 75 watts according to their test sheet. At 75 watts the db level should be around 116 dbs. I think this is a good benchmark, half of whatever your power rating is, so 100 watts would be 50 watts of clean power. Where that is on your volume knob I have no idea, but I think you can easily crank it to 95 db 'C' weighted and be okay as far as clipping goes.
    Not as simple as this. As Cal mentioned, input voltage from source material plays a role. so do the speakers. Speakers that demand higher current (have low impedance profiles)and aren't terribly efficient will be taxing on the amplifier. Some sources output higher voltages. Ever wonder why your TV, CD player, DVD player, XBox, turntable, etc all differ in volume a bit?

    Your proximity to the speakers and other room conditions will dictate the perceived loudness quite a bit as well.

    Your 160 watt amp shouldn't be clipping at 75 watts, or it shouldn't be rated at 160 watts/channel.

  5. #5
    Audiophile Wireworm5's Avatar
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    My test sheet says .74 RMS at 8 ohms, 2 KhZ which could be a percentage, in which case it would be like 118 watts. At this level the the Total Harmonic distortion is less than .002 and intermodulation distortion .0025.

  6. #6
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    Quote Originally Posted by kexodusc
    Not as simple as this. As Cal mentioned, input voltage from source material plays a role. so do the speakers. Speakers that demand higher current (have low impedance profiles)and aren't terribly efficient will be taxing on the amplifier. Some sources output higher voltages. Ever wonder why your TV, CD player, DVD player, XBox, turntable, etc all differ in volume a bit?

    Your proximity to the speakers and other room conditions will dictate the perceived loudness quite a bit as well.

    Your 160 watt amp shouldn't be clipping at 75 watts, or it shouldn't be rated at 160 watts/channel.

    I thought the wattage more or less doubled when you halved the impedence? wouldn't a lower impedence speaker be louder in effect?

    My question is left unanswered. Is it really so that the amp is already clipping when delivering its rated wattage? hmmm hard to be believe. I heard that the "10dB's" under the max volume "0dB" are effectively exponential dB's (the volume would be 10dB's lesser than the max would volume would allow for). This sounds kind of bizar and is perhaps hard to understand (on top of that SPL depends on sensitivity, impedence and signal input "loundness" - which depends on voltage I guess??).

    I am guessing, through this, that I can go up too "-3dB" (volume setting) whithout the amp clipping, considering the fact that when you up the sound pressure by 3dB's, it requires double the wattage...

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    Quote Originally Posted by audio amateur
    I thought the wattage more or less doubled when you halved the impedence? wouldn't a lower impedence speaker be louder in effect?

    My question is left unanswered. Is it really so that the amp is already clipping when delivering its rated wattage? hmmm hard to be believe. I heard that the "10dB's" under the max volume "0dB" are effectively exponential dB's (the volume would be 10dB's lesser than the max would volume would allow for). This sounds kind of bizar and is perhaps hard to understand (on top of that SPL depends on sensitivity, impedence and signal input "loundness" - which depends on voltage I guess??).

    I am guessing, through this, that I can go up too "-3dB" (volume setting) whithout the amp clipping, considering the fact that when you up the sound pressure by 3dB's, it requires double the wattage...
    It is actually a logarithmic scale. For every doubling of power you gain 3 dB thus for most normal listening with efficient speakers you are listening well below 1 watt! The same scale is true for ALL listening levels. Do the math, from 1 watt to 128 watts; you double the power 7 times. You gain 21 dB total! Remember if the speaker starts at 90 dB/W/m you will be able to drive it to about 111 dB with 128 watts, though you will have no headroom for transients.

    To restate the answer to your question, the readout has nothing to do with anything other than being a convince to you so you can repeat a desired result. PEROID!

  8. #8
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    Quote Originally Posted by Cal Blacksmith
    It is actually a logarithmic scale. For every doubling of power you gain 3 dB thus for most normal listening with efficient speakers you are listening well below 1 watt! The same scale is true for ALL listening levels. Do the math, from 1 watt to 128 watts; you double the power 7 times. You gain 21 dB total! Remember if the speaker starts at 90 dB/W/m you will be able to drive it to about 111 dB with 128 watts, though you will have no headroom for transients.

    To restate the answer to your question, the readout has nothing to do with anything other than being a convince to you so you can repeat a desired result. PEROID!
    Alright I was just trying to figure out when my amp starts to clip ( to know whether or not I am damaging my speakers), given the fact that is sounds clear even at max volume...

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    Any loud explosion when you are at maximum volume (transient peak) will definitely clip you amp. It will *not* sound so clear anymore. Your tweeter might even blow.

  10. #10
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    You can't always tell

    when clipping will begin from the setting of the volume control. A lot is dependent on the levels at which your program material was recorded. If the dynamic range is small, you can set the volume high in the knowledge that the peaks won't be very high. If the dynamic range is high and you set the volume high during a quiet passage, things could be driven to destructive levels when you reach a loud passage.

    By the way, how often do you listen at full volume? If I did that, both my speakers and my ears would be destroyed.

  11. #11
    Suspended markw's Avatar
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    Quote Originally Posted by audio amateur
    Alright I was just trying to figure out when my amp starts to clip ( to know whether or not I am damaging my speakers), given the fact that is sounds clear even at max volume...
    You run it at the zero db setting often?

    Remember, regardless of the level setting on the receiver, it's the level of the input signal that determines what "wattage" the unit is actually putting out.

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    From a sensitivity measurement of a speaker, how do you calculate how loud it will be given a wattage?

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    Good Topic

    I was wondering the same thing. From what i understand when you calibrate your receiver via an auto calibration feature such as MCACC or YPAO it tells the Pre stage to add a certain ammount of gain to the input signal. This signal is then sent to the power amp where the signal is then amplified proprtionally to the signal received from the pre stage so that the same spl reaches the listening position from all speakers. Am i right so far? Is it possible to tell your Receiver to limit the gain from the pre stage to avoid clipping regardless of how high you have the volume setting?

    Thanks,

    Wayne

  14. #14
    M.P.S.E /AES/SMPTE member Sir Terrence the Terrible's Avatar
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    Keep in mind. The measured value is based on a single tone (2khz), not from 20-20khz. You may get a lot less power at 100hz, 50hz and most importantly 20hz. Also there is no indication of how many channels are being tested at once. You may be able to get 74 watts with one channel playing ONLY, but less when other channels are added into the mix.
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  15. #15
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    Quote Originally Posted by markw
    You run it at the zero db setting often?

    Remember, regardless of the level setting on the receiver, it's the level of the input signal that determines what "wattage" the unit is actually putting out.
    No I honestly never have it at max volume, I never pass the -10dB setting because first of all my speakers are already distorting and I am scared it might the receiver might start to clip (either that or it already is clipping), but honestly I could'nt bare pushing it anymore it would be too loud, even for a party. But then again it depends what speakers you have. My sats cant't handle anymore and degrade in sound quality pretty fast after that mark. It's pretty loud at -10dB... It's only really when I am hosting parties that I ever worry about it, and even then I am not too concerned. Thanks for all your input (all of you).

  16. #16
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    How does this affect your equipment when using an outboard amp for select channels? Such as having a 100w/ch receiver powering a few speakers, and a 200w amp for the mains, will the 200w amp push harder during a transient peak than the 100w receiver, potentially damaging your speakers? Or are the amps delivering equal power controlled by the pre stage from calibration?

    Wayne

  17. #17
    test the blind blindly emorphien's Avatar
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    Quote Originally Posted by Sir Terrence the Terrible
    Keep in mind. The measured value is based on a single tone (2khz), not from 20-20khz. You may get a lot less power at 100hz, 50hz and most importantly 20hz. Also there is no indication of how many channels are being tested at once. You may be able to get 74 watts with one channel playing ONLY, but less when other channels are added into the mix.
    Good point. I don't know anything about your receiver or how honest Technics is with the power rating. Do they rate that as max output through one channel or max simultaneously through all channels? etc. Different companies are better about their ratings than others, and better equipment will be able to sustain high output and still have some headroom leftover.

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    I all about how much power you can get from the receiver's power supply. With a receiver all channels are sharing a power supply which is limited by how much current can be drawn from its transformer/s and output transistors (total wattage). Content, such as explosions or music with heavy bass draws more wattage because it takes more for the movement of the woofers. Higher amplitute draw more current. You can get away with it for short durations (peak instaneous wattage) since fans and heatsinks can dissipate some of the heat from the current. But, continuous high current, such as party music with heavy bass, may produce more heat than the fan and heatsinks can dissipate either causing the wire insulation in the transformer to melt and shorting, or the output transistors to burn out.

    Using an external amp with a receiver frees up some of the wattage for the remaining channels as would having an external powered subwoofer and setting your speaker size setting to small. You can use the external on the mains and leave them set for large providing the amp has the power. Another option is to use the external amp in a bi-amp configuration on the mains if the speakers are bi-amp capable. Let the receiver drive the mid/high frequencies (less power hungry) and the external amp handle the bass.

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    My main concern was regarding damaging the speakers if too much power were delivered to them. 100w is the suggested max power input for the speakers, the amp is rated @ 150w/ch and the receiver is rated @ 130w/ch.

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    I'll try to be more clear

    I have a pair of studio 20's, pio 72tx receiver, and im looking at adding a nad c272. The pio is rated @ 130w/ch, the nad is rated @ 150w/ch. The 20's suggest a max power input of 100w. Will these components ever deliver a damaging ammount of power to my speakers, such as during a transient peak, or would my ear drums rupture before i ever reached that ammount of wattage? Is this overkill, or am i worrying for nothing?

    Wayne

  21. #21
    Suspended markw's Avatar
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    Quote Originally Posted by wayner86
    Will these components ever deliver a damaging ammount of power to my speakers, such as during a transient peak,
    Most likely not unless you're really stupid and really, really overdrive the unit into gross distortion, or "clipping". Speakers can absorb, on the whole, quite a bit more clean power than their stated maximum for a period of time but it's an overdriven, grossly distorted signal that really does speakers in.

    And, you can very easily "clip" an amp that's rated at a lower watage than speakers are rated to be able to handle.

    Rule # 1 in audio is: "If it sounds bad, turn it down NOW!" You can ignore this at your own risk.

    Quote Originally Posted by wayner86
    or would my ear drums rupture before i ever reached that ammount of wattage?
    Most likely. See Rule # 1

    Quote Originally Posted by wayner86
    ...or am i worrying for nothing?
    Most likely. See rule # 1 and decide for yourself
    Last edited by markw; 03-30-2006 at 05:33 AM.

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