How much Power does my AVR need?

[SimonK]

Hello, 

 

i have a couple of questions someone hopefully can answer. 

 

1. How much Power do i need for a 5.1 Set with 2x 280f, 1x 450c and 2x 250s? The Sw 115 should not count here - right?

- the amp should have at least 80% of the continuous lost for the speakers. 

- twice the power of the speakers? 

- a little bit more then the speakers? 

- or it does not matter at all because klipsch is so efficient?

i heard about everything of these answers. 

 

I bought a Denon x3400H for another set of speakers and i did not like those, so i ended up with the Klipsch set described above and i am not sure if the AVR does it for that.

It has 105W at 8Ohm at 70 efficiency which then should be probably something about 73.5W right? But it has 600W total so actually if you connect a 7.x system it would be 60W per channel -do i understand that correctly? 

 

A Sensitivity level of 98db/watt/m with 73.5 Watt am should give me 116.66 dB or is it 105W then it would be 118.21db? 

 

I just dont understand what the continuous power rating on the speakers has to do with all this!

Is this output somehow lessened by some resistance because they are 150W rated?

If i would buy a Yamaha 3070 with 150WPC then it should only output very little more - 119.76db .

Am i calculating this correctly? 

 

So what is the downside of a less powerful amp?

That it starts to clip at some point?

Is it clipping at a different point with a 100W speaker then for a 150W speaker?

I am assuming the distortion factor is here a factor.

Is it going to be fine if i set my AVR to 0db and go crazy with the volume?

How big is the distortion factor going to be at that level. 0.08% as sated in the manual or higher?

I understand that this is dependent on the input signal. 

 

2. What if i set the AVR to Biamp would that not blow the tweeters very quickly?

Because the AVR does not give me the option to regulate the output on the channels or the crossover. 
So i am assuming it is going to pump full power trough the tweeter or is this regulated dynamically by the receiver or internally by the crossover of the speakers?

Sorry i am missing tons of information probably - hope you are patient with me

 

Thank you very much for your time! 

 

Cheers, Simon

 

 

 

 

 

Edited August 28, 2017 by SimonK

[carlthess40]

Well you've opened a can of worms. Lol. But bottom line is you will be good with what you have. And as for the biamp The cross over will handle the power portioning and if you have odyssey on the receiver when you run the odyssey it will help adjust the levels for the Tweeter . you will get a better sound out of that speaker if you biamp them. because it will be getting 100 watts for the lows and 100 for the highs for combined power of 200 Watts to that speaker. There's still a lot of good receivers out there that I only have 75 Watts per channel and do just fine. But with more power, you should have a higher headroom before going into distortion. And with such high efficient speakers you will be utilizing your power much better with better headroom

More people will chime in with the definitions for your questions of rms, Peak power and distortion vs clipping and so on. You have a great speaker setup that will reproduce the true sound that the engineers meant to be heard

 

 

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[wvu80]

Good reply by Carl ^^^.  Note his iPhone autocorrected the term "odyssey" when Carl tried to say "Audyssey."

 

 

[SimonK]

Well thanks for the quick answer.

 

1 hour ago, carlthess40 said:

for the biamp The cross over will handle the power portioning

which crossover? The crossover of the speakers? How is it regulating power? If that where the case overpowering a speaker and clipping issues would not be a problem at all, 
because the speaker would simply not permit more power in than it can handle. That is not the case for any speaker as far as i am aware. 

 

Quote

it will be getting 100 watts for the lows and 100 for the highs for combined power of 200 Watts to that speaker

If you look at the BIAmping page by Klipsch it says you should connect 150W to the Woofers and 50W for the Tweeter. The woofer actually does not get the 50W that the Tweeter has to much because it is on a different amt. The max would be 150W then right? 

I would only let the Woofer take full advantage of the 100W amp right?

But as there is nothing that would limit the power between the speaker and the amp the tweeter would start to die at about 114.99db  at which point the avr would start to push in more the 50W. Is that assumption right? Sorry you are probably going to lough a this point

 

47 minutes ago, wvu80 said:

It is not because you want the speakers to play louder, it's because of dynamic head room

Well actually isnt dynamic headroom playing louder then your loud current average value?

The Dynamic headroom difference should be only  1.13% in dB between 105W and 150W - not factoring in peak here. 

 

47 minutes ago, wvu80 said:

If you have a car with 100 horsepower it will go a hundred miles per hour, and so will a car with 300 horsepower.  If both cars are traveling at 80 mph and both cars gas it to get to 100 mph, the car with 300 HP still has a lot of punch whereas the lower powered car does not.  AVR power is much the same way.

Great analogy - but i got that

 

I would kindly ask for some numbers here this does all sound like a little bit of hearsay and guesswork - sorry no offense. But i was reading such answers all weekend long.

I am not really interested if it is adequate or not. I am trying to understand at which point it gets inadequate. Because it is going to be inadequate at some point.

But at which point is that? even a 10W amp should still output 108dB right? How big of a clipping is that going to cause for this amp? And how much is THD going to cause additional issues here?

 

https://www.allaboutcircuits.com/technical-articles/the-importance-of-total-harmonic-distortion/

 

Thanks! 

 

Cheers, Simon 

Edited August 28, 2017 by SimonK

[carlthess40]

That's one of the biggest things I hate about my iPhone. Lol


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[willland]

SimonK,

 

Welcome to the forum.

 

1 hour ago, SimonK said:

I would kindly ask for some numbers here this does all sound like a little bit of hearsay and guesswork - sorry no offense. But i was reading such answers all weekend long.

I am not really interested if it is adequate or not. I am trying to understand at which point it gets inadequate. Because it is going to be inadequate at some point.

But at which point is that? even a 10W amp should still output 108dB right? How big of a clipping is that going to cause for this amp? And how much is THD going to cause additional issues here?

Unless I just missed it, nowhere do I read about the size(volume ft3) of your room or how far your main listening position is from front soundstage.  Very important information if you are seeking an accurate assessment.

 

Bill

[RoboKlipsch]

I'll try to keep the answer short and straightforward --

 

generally speaking the loudest MOST people will ever listen is REFERENCE, which is a standard developed by the movie industry to actually have standards in theaters.  This has translated to home use, and is typically a system's ability to reach 105db peaks (we are ignoring the subwoofers for now).  Typically a continuous 85db is the spec in a theater, with 20db bursts to 105db.  That's kind of too loud in a home so 75db is reference in a home system with 30db peaks.  So it is the same as a theater reference but uses a lower continuous standard in order to make it easier on the ears at home and realistic for a smaller room like a home theater or living room.

 

Most speakers sensitivity is rated at 1 meter away, or roughly that.  So if a Klipsch speaker has a sensitivity of 90db, that means at 1 watt -- at 1 meter away -- it has 90db of output. That's obviously a lot.

 

A typical listening distance is maybe 10 feet away, and to make things simple, assume that at that distance, you lose 10db of sensitivity due to the distance.  At 1m, a speaker may have a sensitivity of 90db, but when you sit 10 feet away instead of 1m, it is roughly 80db.

 

So the way I look at it is this -- most systems, to achieve what 98% of people would ever listen to, need to be able to reach reference levels at the listening position.  So if I am at 10 feet away listening, and 105db is reference...I want a SYSTEM that can output 115dbs total at a distance of 1m...which is what most speakers are spec'd at.  

 

So let me do the math for you for the 280s and you can do the rest --

 

They have a sensitivity of 98db, they are 8ohm 

At 10 feet away, we lose that 10db, so they are 88db at 10feet away

 

88db @ 1w

91db @ 2w

94db @ 4w

97db @ 8w

100db @ 16w

103db @ 32w

106db @64w -- refence level

109db @ 128w - would be headroom above reference

 

There you go....at just under 64w your front speakers can play at reference level (105+db @ 10feet)

So you want an AVR that can output a true 64w per channel to be able to achieve reference

Can your center hit reference?  You do the math, start with where the sensitivity is at 1w, then use the above

 

Now what would it mean to have more power than this?  It would mean that the system can run a bit cooler, and that you have the ability to play it even louder than reference if you want to.  Because reference is related only to movies, some music tracks are recorded rather low, and require reference level or higher in order to get the full sound you may want.

 

So how much power do you need....can be figured quite easily, you have to get into the details a bit to understand it.

Will you listen at reference frequently?  I doubt it, but some do.  It's really, really loud in a home theater.

 

I don't want to get into the details here but many Denons have been tested and actually do output most of what they say they can do.

Often you can google the model # and "bench test" and some engineer out there actually took the time to run it through a testing rig that can really measure it

my denon 3808 came out almost exactly to what was specified 

 

[JohnA]

 

The speaker's power rating is the max it can absorb without damage, possibly for a second, or 2.  It is a relatively meaningless rating, but don't exceed it on purpose.  How would you know?  You'll suddenly get no sound or a puff of smoke. 

 

Your peak sound levels during any movie should never exceed 105 dB, 100 dB is much better. 

 

Each doubling of speakers with their own amp channel adds 6 dB. 

 

Each doubling of distance from the speakers looses about 6 dB (indoors, reflections modify that rule a little). 

 

If all 5 of your speakers were 98 dB/w/m, you'd get 98 + 6 for two fronts, + 6 for 2 rears, and let's say +3 for one center = 113 dB for all 5 at 1 meter. 

 

Well, nobody sits that close, so let's assume you are 4 meters from all speakers, about 13 feet.  Two meters is -6, 4 meters is -12 dB, now we are at 101-ish dB for the system with all speakers, at 98 dB/w/m, getting ONE WATT.  From one watt to 3 watts/channel adds about 5 dB to the system for 106 dB. 

 

Does your receiver have enough power??!!  Hmmm.   

 

You wanna reproduce a 3 Doors Down or Nickleback concert in your listening room, you're gonna need another 100 watts, or so. 

 

My La Scalas run 104 dB/w/m.  My Heresies run 94 dB/w/m.  This one is easy, for me as a Heresy needs 10x the power of a La Scala to get as loud.  So, while my La Scalas are running maybe a 1/2 watt, the Heresies get 5 watts to keep up.  The 5 mains are connected to an amp that can produce 140 watts/ch.  At 92 dB/w/m, my subs are getting 20 watts (out of at least 350/channel).  Nothing succeeds like excess.   

 

You will have to adjust the power levels for your center and surrounds like I just did, but I'm betting in 3 - 5 watts in those channels. 

 

What we all need is a good 50 watt amp! 

[SimonK]

Hello,

 

Thank you all so much for your effort! Much appreciated!

Btw.: Love your humor  

 

Hmmm well i did know the calculations for that but i actually must admit that i am not sure at what level i am listening. 

There isn't really a dB scale on any of my devices that would tell me that. 

I am just a little scared that i at some point just blow the entire thing.

Id just wanted to understand what happens if i push it to the limit.

How does the biamp work now? Can i just connect the Tweeter to one amp without having to far that i blow it?

Do i not have to put in another crossover or something in between? Anything else to worry about?

 

All this "don't under-power you speakers" discussion got me very worried. 

I understand that this all matters only at crazy high sound levels.

 

Thanks guys

[wvu80]

..

[garyrc]

2 hours ago, John Albright said:

Each doubling of distance from the speakers looses about 6 dB (indoors, reflections modify that rule a little). 

 

Paul Klipsch's tests measured a decline of about 3 dB for every doubling of distance, indoors.  He described three doublings as reducing SPL by about "8 or 9 dB,"  when comparing two frequency response curves (20 to 20K Hz) taken at 2 feet and 16 feet.  He characterized 16 feet as "a listener's normal ear location."   He used Klipschorns.  I don't know the room size, but it may have been the room at Hope that is about 25 feet by 16 feet, with ceiling height unknown (to me). 

 

 

[carlthess40]

Well said Mr Albright


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[RoboKlipsch]

I dont think you will observe the bump in spl from colocating the speakers i.e. left and right together +6db.  That would be true playing an identical signal only which almost never occurs except in mono music.   

 

2 identical signals close together can theoretically gain 6db i.e. subs but again thats very close together.  I have observed closer to 4db for doubling of sources in a normal layout

[SimonK]

7 hours ago, wvu80 said:

Do you have this bi-amping thing worked out yet, Simon?

No i don't have that worked out at all. Did i miss anyone answering that question. 

carlthess40 did kind of answer that but then i had open questions about it.

 

6 hours ago, wvu80 said:

You have the  Denon x3400H.  It is not capable of bi-amping when used with Atmos.

XD yes i get that

 

The major thing i learned in this discussion is - that 100db is crazy loud.

I actually never thought about it that much.

 

 

I understand why distance is a big issues as it causes additional problems with cabeling and of course reduces the pressure over distance -significantly!

Here is an actual article about that http://www.sengpielaudio.com/calculator-SoundAndDistance.htm

 

My equipment would probably die 5 min after i got deaf at the 12 feet distance i am listening, but still my question remains.

Would the tweeter die at 114.99db /1m/1f in a biamping scenario or in other words the point at which the amp would exceed the 50W limit.

I am curious about that now. The biamping is just very confusing for me in general. I probably have to do the math on that to understand it.

But the crossover in the speakers does not per say have a voltage/current regulator/limiter right? 

 

Well as always thanks for your time

[garyrc]

114.99 dB, if sustained, would surely kill your tweeter, BUT in classical, orchestral, or movie music, you would not have anywhere near 114.99 dB in the tweeter range.  With Rock, alternative, metal, and electronic music, exercise extreme caution.   Tweeters can be blown fairly easily by unplugging an RCA interconnect cable when the equipment is on, by running a test signal too loud, or, if you are lucky enough to have a reel to reel tape recorder, by advancing a tape at high speed with the volume up.

 

With some movies played at reference level, there will be peaks of 105 dB through your regular channels, and 115 dB through the subwoofer.   But, the average level will be in the 70s and 80s, with loud passages more like 90 to 100 dB.

 

The chart of permissible lengths of exposure you reproduced is considerably more stringent then OSHA levels.  Google OSHA, U.S. Dept of Labor.

 

[wvu80]

Have you hooked up your AVR to your Klipsch speakers yet?  If not, what are you waiting for?

[SimonK]

21 minutes ago, wvu80 said:

I'm a little lost, Simon.  If you understand your AVR will not support bi-amping while running Atmos, then what exactly do you need to figure out?

 

Who says i am running Atmos? You just assumed that i am.

I did not say anything about it and i also did not post a Atmos speaker. *Hint*

No thanks i don't have anymore questions.

Thanks you for your help and your time!

Have a great day

[wvu80]

Have you hooked up your speakers to the Denon and played them?

[JohnA]

Hey Simon,

 

Bi-amping your mains(?) won't help you unless you can use a delay to time align the HF to the woofer and you can bypass the internal crossover.  It requires a crossover with the delay built in.  Does your receiver have that capability?  Most modern Klipsch are setup to bi-wire.  I don't believe it has any sonic benefit as long as your speaker wires are large enough, others will disagree.   

 

Bi-amping is used in Pro Audio to get more power to the speaker array, but you don't really need that, either. 

[carlthess40]

This discussion is getting to where I am bowing out you gentlemen have a wonderful day


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