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#1 ·
I just received an email from Emotiva with the information about the XPR-5. So, who is going to buy one of this monsters?








http://shop.emotiva.com/collections/amplifiers/products/xpr5


SPECIFICATIONS


Topology: Fully discrete, dual differential, high current, short signal path Class A/B amplification with Optimized Class-H™ power supply topology.

Number of Channels: 5

Power Output

(rated power; THD
400 watts / channel (x5); all channels driven; into 8 Ohms.

600 watts / channel (x5); all channels driven; into 4 Ohms.

500 watts / channel (x2); two channels driven; into 8 Ohms.

750 watts / channel (x2); two channels driven; into 4 Ohms.

575 watts / channel (x1); one channel driven; into 8 Ohms.

1100 watts (1 .1 kW) / channel (x1); one channel driven; into 4 Ohms.

Rated Power Bandwidth (at rated power; 8 Ohm load): 20 Hz to 20 kHz + /- 0.01 dB.

Minimum Recommended Load Impedance (each channel): 4 Ohms (which equals one 4 Ohm load or two paralleled 8 Ohm loads per channel).

Frequency Response: 10 Hz to 80 kHz (+ 0 / - 1 dB).

THD + noise:
Signal to Noise Ratio (8 Ohm load):

> 93 dB at 1 watt (A-weighted).

> 109 dB at rated power (A-weighted).

Damping Factor (8 Ohm load): > 500

Speaker Output Connections:

Super heavy duty audiophile speaker binding posts - with clear acrylic insulators and heavy duty gold plated contacts; designed to accept heavy-gauge bare cables, lugs, or banana plugs.

Power Supply:

3.3 kVA toroidal power transformer.

180,000 uF of storage capacitance.

Input sensitivity (for rated power; 8 Ohm load): 1.875 V

Gain: 29 dB

Input Connections:

Unbalanced (Tiffany style, audiophile quality, gold plated RCA); one per channel.

Balanced (XLR); one per channel.

Each input may be independently switched to either unbalanced or balanced.

Input Impedance:

47 kOhms (unbalanced).

22 kOhms (balanced).

Trigger:

Trigger Input: 5 - 20 V (AC or DC);
 
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#177 ·

Quote:
Originally Posted by duc135  /t/1418604/emotiva-xpr-5/150#post_23899844


I never claimed that measuring voltage indicated anything other than what my speakers were drawing while playing at reference. Read my posts again. I never even used the word clipping. Please do not read into my posts any inferences as all I stated was the power draw of my speakers in my room at reference. Nothing more, nothing less.


I was providing the OP the numbers so that he can make in informed decision. If my inefficient (86dBs) speaker only needs 150W to achieve reference, he may not notice a difference from his 100+W receiver and an external amp using efficient (98dBs) speakers. I was stating that my measured results are nearly spot on with the calculated power requirements. If this is the case, then he would only need 16W to surpass reference level SPL at 2m. Do you think he would be best served by spending close to $2K to supply his speaker with 16W when even an entry level receiver can do that?

I was actually able to determine how much power your amp was delivering by reading your post.

No with 98DB at 1 watt it is unlikely that he needs are powerful amp.
Quote:
Originally Posted by duc135  /t/1418604/emotiva-xpr-5/150#post_23899844


See below. You stated to hit 106dBs in your room it took 200W.


Again, if your 600W amp is clipping delivering 200W then there is something wrong with your setup. Those are the numbers you are providing, not me.

Measuring the speakers at the terminals you are getting a slow reading of how many watts are being delivered to your speakers not the power that should be delivered.


The AV8801 THX preamp uses 0 as reference and a negative scale.

At -6 DB and the ATI3005/Salons clip indicators have come on. At -3, they have been on half the time.

At 0, they are on most of the time. In all, it is too damn loud for me.

I do not hear very objectionable clipping, yet the amp is clipping so there is compression.


So why bring up clipping, the whole point of sizing and AMP is to select an amp that does not clip to have the best possible reproduction. When you clip, less power is delivered. Less power means less bass, or control, and compression.


You seem to be using the term Reference to indicate THX reference 85 DB plus 20DB headroom.

That should not be confused with 0 in a negative scale AVR/Preamp.


Since I have not provided the distance and room size, you cannot possibly compute how much volume I obtain.

I said that if I were listening to 2 watts with 20 DB headroom, it would require 200 watts.

That would be THX movie. For much of my music, I estimate that at -10, is that point at which my amp is running out of power.
Quote:
Originally Posted by duc135  /t/1418604/emotiva-xpr-5/150#post_23899844


Can you explain what you mean by "...the revels are essentially 4 ohm, so in my room that would be 2 watts..." please?

Tests for impedance use sweeps. Tests for efficiency usually use a single tone.

It is possible for a speaker to operate at 8 ohms when using a 1K tone for 86 DB efficiency, yet have 4 ohm or lower impedance at low frequencies so the efficiency rating is not indicative of the power required to drive a speaker like a Salon.


Here is the Stereophile measurements for my Salons :
Quote:
estimated the Revel Salon's B-weighted sensitivity as 87dB/2.83V/m, a mite higher than the specification. However, the Salon is basically a 4 ohm loudspeaker, drawing 2W from the amplifier to achieve its sensitivity rating.


- Rich
 
#178 ·

Quote:
Originally Posted by whoaru99  /t/1418604/emotiva-xpr-5/150#post_23899932


Revel Salon specs (from the Owner's Manual) say the speakers are 6 ohms nominal impedance and 86dB@ 2.83V @ 1m.


Since the sensitivity is rated in volts rather than watts, you have to consider the impedance when comparing sensitivity to other speakers.


For example, 2.83V @ 8 ohms is ~1 watt, 2.83V @ 6 ohms is ~1.33 watt,. 2.83V @ 4 ohms is ~2 watts.


So, if one speaker is 8 ohms with 86dB @ 2.83V sensitivity and another speaker is 4 ohms with 86dB @ 2.83V sensitivity, the net sensitivity of the 4 ohm speaker is actually only 83dB if you rate them in terms of dB per (1) watt. Since the Revel Salons are nominally 6 ohms, relative to 1 watt of power their sensitivity is roughly 84.8dB.


Rather than the individual specifics, the key point is understanding that speakers can be rated differently in terms of sensitivity.


If the ratings are all in dB/W/m then you can compare them pretty straight up. If the ratings are dB/2.83V/m then you have to factor in the speaker impedance to arrive apples-to-apples sensitivity ratings.

Here is the Stereophile measurements for my Salons :
Quote:
estimated the Revel Salon's B-weighted sensitivity as 87dB/2.83V/m, a mite higher than the specification. However, the Salon is basically a 4 ohm loudspeaker, drawing 2W from the amplifier to achieve its sensitivity rating.

If you look at the impedance curve over the frequency sweep it varies. So if you use a 1KZ tone you will not get a value indicative of music.


The same holds true for the Stereophile measurements of the Salon2 . At 1KZ you would be at 8ohms but from 17 to 600hz it is a 4 ohm speaker.

So if you want to size your amp, using DB at 1 watt of music, 83 DB would be a safer figure.


- Rich
 
#179 ·
The point was the information about deciphering different ways sensitivity specs are provided and how to interpret them relative to each other. Not to nit pick Stereophile vs. Harmon measurements. Harmon picked their number based of their test methodology and that's what I used. It's no more, no less than that.
 
#180 ·

Quote:
Originally Posted by whoaru99  /t/1418604/emotiva-xpr-5/150#post_23900150


The point was the information about deciphering different ways sensitivity specs are provided and how to interpret them relative to each other.


The difference between Stereophile measurements and Harmon's measurements is minutae of detail I have no particular interest in. Harmon picked their number based of their test methodology and that's what I used. It's no more, no less than that.

It just so happens that the Salons have been carefully measured and the information is available for other speakers as well.

Efficiency ratings may not tell the full story due to impedance curves and phase.


I provide this information for those who are interested. Maybe I should add that to my signature



- Rich
 
#181 ·
LOL.


The point was the information about deciphering different ways sensitivity specs are provided and how to interpret them relative to each other. Not to nit pick Stereophile vs. Harmon measurements. Harmon picked their number based of their test methodology and that's what I used. It's no more, no less than that.
 
#182 ·
I liked my Yamaha RX-V2700 AVR that powered five B&W CM7/CMC/CM1 a lot. But swapping it for a UMC-1 (bought for the Upgrade Certificate, intended to sell it on) plus the XPR-5 (bought for the ever ongoing HT-build/plans elsewhere) made a surprisingly big jump in SQ. I believe the power of the XPR-5 is a big help. The little CMC center speaker actually sounds good now (I intended to swap that one out for the larger center not available first but didn't get to it). Admittedly it's only 84 dB sensitive, but we sit close @ less than 8 ft. I ended up selling the old AVR. If the XPR-5 ever makes it to the HT, I will however replace it with a XPA-5. Even bought a second Upgrade Certificate because I want to have the next generation processors in both our homes.


Also, the Atmos™ equipped cinema in The Netherlands where we experienced The Hobbit last winter, claims to have 94.000 Watt available as where a standard movie theatre has 7.000 Watt. I guestimated about 48 speaker positions in that medium sized space. It played loud, but without distortion. That headroom IMO is a huge part of the perceived SQ. This was a total new build, mind you. I need want to see Gravity there, in order to get my Atmos™ fix, but my decisive other half is opposed to the 90 minutes drive towards JT Vlaardingen near Rotterdam. Bugger!


In the end, there might be no substitute for cubic inches... whether it comes as liters or Watts.
 
#183 ·
First off, thank you whoaru99 and RichB for the clarification on the Harman sensitivity spec.

Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23899978


The AV8801 THX preamp uses 0 as reference and a negative scale.


You seem to be using the term Reference to indicate THX reference 85 DB plus 20DB headroom.

That should not be confused with 0 in a negative scale AVR/Preamp.


- Rich

0 on the MV using the negative scale is the same as THX Reference 85dBs. -1 on the MV would indicate -1dBs from THX Reference or 84dBs. What do you think 0 on your AV8801 designates?
Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23899978


Since I have not provided the distance and room size, you cannot possibly compute how much volume I obtain.

I said that if I were listening to 2 watts with 20 DB headroom, it would require 200 watts.

- Rich

I never computed anything about your system. You stated that a grand piano can hit 106dB and it takes your system 200W to do so. It was you you stated those numbers, not me. All I said is that if it takes 200W for your system to reach reference and your 600W amp is clipping then something is wrong. At -6 on your MV you should be only drawing ~50W peak based on your stated 200W for 106dB. If even 50W is causing your amps clip lights to come on intermittently I personally would suspect something is wrong or your numbers are off.


Recalculating based on the numbers you and whoaru99 provided, I see that it would take ~250W to reach reference at 1m. I can't imagine anyone sitting only 1m from the Salon2s so at 2m that number goes up to 500W which is more in line with causing your clip lights to come on as I would guess even 2m is probably even too close to be sitting from the Salon2s. Based on those numbers, I sure am glad I have the XPR-5 driving my Salon2s as I'm over 2m from my speakers.
 
#184 ·

Quote:
Originally Posted by duc135  /t/1418604/emotiva-xpr-5/180#post_23913593


First off, thank you whoaru99 and RichB for the clarification on the Harman sensitivity spec.

0 on the MV using the negative scale is the same as THX Reference 85dBs. -1 on the MV would indicate -1dBs from THX Reference or 84dBs. What do you think 0 on your AV8801 designates?

I do not know, it has a positive scale and a negative scale.

If you set it to negative it goes past 0 to +18.

However, if you set a -10 DB volume limit, it only allows you to get to -10.

Unless the scale shifts, then -10 reduces the gain by 29 DB. That makes no sense.
Quote:
Originally Posted by duc135  /t/1418604/emotiva-xpr-5/180#post_23913593



I never computed anything about your system. You stated that a grand piano can hit 106dB and it takes your system 200W to do so. It was you you stated those numbers, not me. All I said is that if it takes 200W for your system to reach reference and your 600W amp is clipping then something is wrong. At -6 on your MV you should be only drawing ~50W peak based on your stated 200W for 106dB. If even 50W is causing your amps clip lights to come on intermittently I personally would suspect something is wrong or your numbers are off.

A 5 DB peak at that level would clip that amp. If you cannot amplify the peak, it clips.

The power is not produced and at some point you hear distortion.

Quote:
Originally Posted by duc135  /t/1418604/emotiva-xpr-5/180#post_23913593


Recalculating based on the numbers you and whoaru99 provided, I see that it would take ~250W to reach reference at 1m. I can't imagine anyone sitting only 1m from the Salon2s so at 2m that number goes up to 500W which is more in line with causing your clip lights to come on as I would guess even 2m is probably even too close to be sitting from the Salon2s. Based on those numbers, I sure am glad I have the XPR-5 driving my Salon2s as I'm over 2m from my speakers.

These are really loud volumes which I like for the occasional binge


It does not hurt to have the power when you get loud it goes fast.


- Rich
 
#185 ·
If the system is calibrated then 0dB setting of the volume control should reflect calibrated (reference?) level at the spot where the calibration mic was. Or, in the case of multipoint calibration somewhere about the center of the group, presumably.


If one sets a -10dB volume limit then you'd be going no higher than 10dB below calibrated level / 0dB. Of course, if the source material/input signal is stronger or weaker than what was used for calibration, the absolute level will no longer be calibrated to the reference, but would still be relative (10dB less than what ever 0dB is).
 
#186 ·

Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23914378


I do not know, it has a positive scale and a negative scale.

If you set it to negative it goes past 0 to +18.

However, if you set a -10 DB volume limit, it only allows you to get to -10.

Unless the scale shifts, then -10 reduces the gain by 29 DB. That makes no sense.

- Rich

On a positive scale 85 is reference. If you you turn the dial to 60 that means you're getting 60dBs from your speakers from a calibrated tone. On the negative scale 0 is reference. If you set the MV to -25 then you are getting 60dBs from your speakers using a calibrated tone. So if you are using a negative scale and set your MV to +18 then you are 18dBs over reference or 103dBs with peaks of 123dBs. The volume limits you set on your receiver are only that, volume limits. They have no bearing on calibration. This is useful if you have little ones or a system is not capable of hitting reference without damage. If you set the volume limit to -10 in your receiver setup it will not allow you to turn the volume up past -10 thereby protecting your system from potential damage by unknowing people. It does nothing to reduce the gain. It just limits it.

Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23914378


A 5 DB peak at that level would clip that amp. If you cannot amplify the peak, it clips.

The power is not produced and at some point you hear distortion.


- Rich

Agreed. A 5dB peak from 106dB will clip our amps, but that is not what you said. You said at -6 on your MV you are starting to clip your amp. According to your numbers (200W @106dBs) a reduction of 6dB (-6dB on your MV) would reduce your power requirements by 75%. So given that, you are using only 50W at -6 on your MV. If 50W is clipping your 600W amp there is something wrong somewhere. Again, I'm only going off the numbers you provided. I am not telling you what you are actually using based on what I think you are using.

Quote:
Originally Posted by whoaru99  /t/1418604/emotiva-xpr-5/100_100#post_23929748


If the system is calibrated then 0dB setting of the volume control should reflect calibrated (reference?) level at the spot where the calibration mic was. Or, in the case of multipoint calibration somewhere about the center of the group, presumably.

Regardless of how many points of measurement and where, the system volume calibration is based on only the first microphone position. That is why it is placed at the MLP. That first microphone position determines speaker distances and individual channel trims to obtain reference levels. The remaining positions are used only for EQ calibration.

Quote:
Originally Posted by whoaru99  /t/1418604/emotiva-xpr-5/100_100#post_23929748


If one sets a -10dB volume limit then you'd be going no higher than 10dB below calibrated level / 0dB. Of course, if the source material/input signal is stronger or weaker than what was used for calibration, the absolute level will no longer be calibrated to the reference, but would still be relative (10dB less than what ever 0dB is).

+1
 
#187 ·

Quote:
Originally Posted by duc135  /t/1418604/emotiva-xpr-5/180#post_23929945


Agreed. A 5dB peak from 106dB will clip our amps, but that is not what you said. You said at -6 on your MV you are starting to clip your amp. According to your numbers (200W @106dBs) a reduction of 6dB (-6dB on your MV) would reduce your power requirements by 75%. So given that, you are using only 50W at -6 on your MV. If 50W is clipping your 600W amp there is something wrong somewhere. Again, I'm only going off the numbers you provided. I am not telling you what you are actually using based on what I think you are using.

+1

One example to illustrate clipping was my the AV8801/ATI3005 driving my Revel Salons. I could illuminate the clip indicators playing Surfacing by Sarah McLachlan.

They began to illuminate at -6, were on about 50% of the -3, and were mostly on at 0.

There was no awful clipping at -6 and I heard nothing to indicate that the amp was clipping.

If there were no indicators, I would not know that it was clipping the amp.

Of course, with less powerful amps, this clipping would occur as well. It would be loud and sound good, but I would be clipping and compressing the sound.


Some amps advertise "Soft Clipping" which to me indicates a product that compresses to avoid distortion.



- Rich
 
#188 ·

Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23930053


One example to illustrate clipping was my the AV8801/ATI3005 driving my Revel Salons. I could illuminate the clip indicators playing Surfacing by Sarah McLachlan.

They began to illuminate at -6, were on about 50% of the -3, and were mostly on at 0.

There was no awful clipping at -6 and I heard nothing to indicate that the amp was clipping.

If there were no indicators, I would not know that it was clipping the amp.

Of course, with less powerful amps, this clipping would occur as well. It would be loud and sound good, but I would be clipping and compressing the sound.


Some amps advertise "Soft Clipping" which to me indicates a product that compresses to avoid distortion.



- Rich

I understand soft and hard clipping fairly well. I'm not talking about the merits or how it works. All I'm saying is that if the numbers you provided are true, something is wrong if a 600W amp is clipping at 50W, soft or otherwise. That's like saying a 600HP sports car's rev limiter is kicking in when the car is only going at a steady 20MPH. Sure, you can say the rev limiter is doing its job to protect the engine from blowing up, but there is something seriously wrong if that limiter is kicking in at only 8% of its potential. Would you still stand behind that car and say that's the way it's supposed to work? I would think not. I can understand if the amp starts soft clipping at 400W - 500W, but not at a mere 50W.
 
#189 ·

Quote:
Originally Posted by duc135  /t/1418604/emotiva-xpr-5/180#post_23930129


I understand soft and hard clipping fairly well. I'm not talking about the merits or how it works. All I'm saying is that if the numbers you provided are true, something is wrong if a 600W amp is clipping at 50W, soft or otherwise. That's like saying a 600HP sports car's rev limiter is kicking in when the car is only going at a steady 20MPH. Sure, you can say the rev limiter is doing its job to protect the engine from blowing up, but there is something seriously wrong if that limiter is kicking in at only 8% of its potential. Would you still stand behind that car and say that's the way it's supposed to work? I would think not. I can understand if the amp starts soft clipping at 400W - 500W, but not at a mere 50W.

I have completely lost track of what you are talking about.

An amp clips when it hits a peak that it does not have the power to product.

Finding the right sized amp is the trick.


What numbers are you referring to?


- Rich
 
#190 ·

Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23930396


I have completely lost track of what you are talking about.

An amp clips when it hits a peak that it does not have the power to product.

Finding the right sized amp is the trick.


- Rich

I was talking about your setup and why either there is a problem with your setup or your numbers. I merely was stating I know what clipping is and how it works. If your 600W amp is clipping when only asked to push 50W then there is an issue somewhere whether you choose to believe it or not.


Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23930396


What numbers are you referring to?


- Rich

I was referring to these numbers you stated:
Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23897952


A grand piano can produce 106DB.the revels are essentially 4 ohm, so in my room that would be 2 watts, to hit 106DB requires 20X power.

This is about 200 watts.

- Rich

Here you just claimed that in your room it takes about 200W to hit 106dBs.
Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23899978


At -6 DB and the ATI3005/Salons clip indicators have come on. At -3, they have been on half the time.

At 0, they are on most of the time. In all, it is too damn loud for me.

- Rich

Here you state that at -6 on your MV the clip lights begin to flicker. If it takes 200W to hit 106dBs which is +1dBS over reference peaks then at -6 on the MV that would be 100dBs. For every 3dBs increase in volume is a doubling of power requirement. So a reduction in -3dBs is a halving of power. As you stated that it takes 200W to achieve 106dBS then it would only take 100W to achieve 103dBs. Reduce that by 3dBs and that is another halving of power requirements. Now you are down to 50W. Those are the numbers. At -6 on your MV your amp is pushing 50W to your speakers. If a 600W amp is clipping pushing 50W there is something wrong. Keep in mind those are all peak numbers not sustained either as I highly doubt anyone is really listening at a sustained 100dBs.
 
#192 ·
Actually, what I was saying is that it takes 2 watts in my room to achieve 86 DB according to the measurements published in the Stereophile review.

So to hit 106DB is 20 DB more. 20 DB requires 100 times the power, so that would be 200 watts.

If you have a good idea of your loudness desires, the efficiency of you speakers, your room size, you should be able to compute the power needed to avoid clipping.


The Surfacing album example would did not clip the ATI3005 until -6.

I provided this as a real world example.

It was as loud as I would want to go and there is no way I would turn it up to 0.

If I did, I would certainly be clipping that amp and I am sure I would be clipping the A51.

I feel safe up to -10 with the A51 and it is plenty loud.


There is nothing wrong with my equipment.


- Rich
 
#193 ·

Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23930694


Actually, what I was saying is that it takes 2 watts in my room to achieve 86 DB according to the measurements published in the Stereophile review.

So to hit 106DB is 20 DB more. 20 DB requires 100 times the power, so that would be 400 watts.

- Rich

That is not at all what you said. This is what you said:
Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23897952


A grand piano can produce 106DB.the revels are essentially 4 ohm, so in my room that would be 2 watts, to hit 106DB requires 20X power.

This is about 200 watts.


- Rich

Your math is all over the place. 20x the power of 2W is 40W, not 200W (2 x 20 = 40). 100x the power of 2W is 200W not 400W (2 x 100 = 200). A 20dBS headroom as specified by THX reference standard requires approximately 128x the power not 20x nor 100x.


Ok let's do the math if your speaker require 2W to achieve 86dBs then to reach 105dBs you will need 256W not 400W since every 3dBs increase doubles the power requirement. Look at the below table I've created for you:


86dBS = 2W

89dBS = 4W

92dBs = 8W

95dBs = 16W

98dBS = 32W

101dBs = 64W

104dBs = 128W

107dBS = 256W
Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23930694


If you have a good idea of your loudness desires, the efficiency of you speakers, your room size, you should be able to compute the power needed to avoid clipping.


- Rich

Now you know the actual numbers and you won't need to compute the power needed to avoid clipping.


Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23930694

The Surfacing album example would did not clip the ATI3005 until -6.

I provided this as a real world example.

It was as loud as I would want to go and there is no way I would turn it up to 0.

If I did, I would certainly be clipping that amp and I am sure I would be clipping the A51.

I feel safe up to -10 with the A51 and it is plenty loud.


There is nothing wrong with my equipment.


- Rich

So at -6 you are looking at 101dBs peak according to the table above. So you're saying that there is nothing wrong with a 600W amp that clips while pushing 64W? That's less than 11% of its rated power.


That being said, I'm guessing that your original number about what you are drawing is off. 86dBs @ 2W is at a 1m distance. I'm assuming your are sitting a little further away from you Salons than 3.3'. Power requirement doubles for every 1m increase beyond 1m. So here is the modified table based on a 3m distance from the speakers.


86dBS = 8W

89dBS = 16W

92dBs = 32W

95dBs = 64W

98dBS = 128W

101dBs = 256W

104dBs = 512W

107dBS = 1024W


Now it starts looking more reasonable that your amps are starting to clip at -6 on the MV. Like I said, either there is a problem with your setup or your numbers are off.
 
#194 ·

Quote:
Originally Posted by duc135  /t/1418604/emotiva-xpr-5/180#post_23930779


That is not at all what you said. This is what you said:

Your math is all over the place. 20x the power of 2W is 40W, not 200W (2 x 20 = 40). 100x the power of 2W is 200W not 400W (2 x 100 = 200). A 20dBS headroom as specified by THX reference standard requires approximately 128x the power not 20x nor 100x.


Ok let's do the math if your speaker require 2W to achieve 86dBs then to reach 105dBs you will need 256W not 400W since every 3dBs increase doubles the power requirement. Look at the below table I've created for you:


86dBS = 2W

89dBS = 4W

92dBs = 8W

95dBs = 16W

98dBS = 32W

101dBs = 64W

104dBs = 128W

107dBS = 256W

Now you know the actual numbers and you won't need to compute the power needed to avoid clipping.


So at -6 you are looking at 101dBs peak according to the table above. So you're saying that there is nothing wrong with a 600W amp that clips while pushing 64W? That's less than 11% of its rated power.


That being said, I'm guessing that your original number about what you are drawing is off. 86dBs @ 2W is at a 1m distance. I'm assuming your are sitting a little further away from you Salons than 3.3'. Power requirement doubles for every 1m increase beyond 1m. So here is the modified table based on a 3m distance from the speakers.


86dBS = 8W

89dBS = 16W

92dBs = 32W

95dBs = 64W

98dBS = 128W

101dBs = 256W

104dBs = 512W

107dBS = 1024W


Now it starts looking more reasonable that your amps are starting to clip at -6 on the MV. Like I said, either there is a problem with your setup or your numbers are off.

Actually, I was hastily replying as I was running out the door.

I meant 20 DB requires 100 times the power.


I do not disagree with any of these tables. I used the conservative 2 watts for 86 DB because there are room size and stereo speakers.

If I plug these values into the Crown Amplifier Power Request Calculator:


Distance: 3 meters

Desired listening levels: 86

Efficiency: 83 (I knocked it down 3Db since Salons since they are basically 4 ohm speakers)

Headroom: 0

Required Amplifier power = 18 watts


Which is even more than your last table.

I have never been sure why anyone would doubt that approaching 0 reference volume with a Speaker like the Salons would clip most amps, even one as powerful at the ATI3005.


My main point is that you can clip these amps before hitting the reference of 0 and the resulting compression is not easily detected.

I do not mind limiting my volume to -10 for music because that very loud.


This morning, I setup my OmniMic 2 to measure the volume while watching "Indiana Jones and the Last Crusade" with myRevel 5.1 system. Salons, Voice, Studios.

I turned off the Sub.


Normally, I would listen to a movie like this with the AV8801 at 54 (-34) but I decided to go a bit louder to 60 (-28).

During reasonably quiet scenes the reading at my seat (10 feet) was in the 60's.

Loud conversations would rise into to 70's.

Loud Action scenes rose into the 80's (barely)

The peak measured 104. In either table, that is loud.


To me this suggests that THX specs are reasonable for my use. 105 DB (excluding the .1 bass) is all I need for me to enjoy an action movie.

However, for most of the film the amps is cruising down in the 20 to 50 watt range.

At peak volume, pick your table, but It would be likely over 200 watts.

The 86 DB average seems high though because that is quite loud.


- Rich
 
#195 ·

Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/180#post_23932489


I have never been sure why anyone would doubt that approaching 0 reference volume with a Speaker like the Salons would clip most amps, even one as powerful at the ATI3005.


- Rich

I don't think that's been the doubt in anyone's mind.
 
#196 ·

Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23932489


Actually, I was hastily replying as I was running out the door.

I meant 20 DB requires 100 times the power.


- Rich

Now we're starting to come to agreement. This is good. We're making progress.
Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23932489


I do not disagree with any of these tables. I used the conservative 2 watts for 86 DB because there are room size and stereo speakers.

If I plug these values into the Crown Amplifier Power Request Calculator:


Distance: 3 meters

Desired listening levels: 86

Efficiency: 83 (I knocked it down 3Db since Salons since they are basically 4 ohm speakers)

Headroom: 0

Required Amplifier power = 18 watts


Which is even more than your last table.


- Rich

83dBS/1W/1m is the same as 86dBs/2W/1m so my tables are not incorrect. You just need to add 83dBS to the top of the list. I started at 86dBs since that's the number you stated. The Crown calculator uses the actual equation. My table is more of a ballpark. Both of us are ignoring possible boundary gains.
Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23932489


I have never been sure why anyone would doubt that approaching 0 reference volume with a Speaker like the Salons would clip most amps, even one as powerful at the ATI3005.


- Rich

I don't recall anyone doubted that. It was just me really, but I wasn't doubting the Salons can clip a powerful amp, I was questioning your numbers. So based on the insufficient data presented, regardless of what speaker it is, the numbers did not add up. If the numbers were accurate, then the problem existed in your setup. Now that we've cleared that up we can see that there is not an issue with your setup, but one of missing data.
Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23932489


My main point is that you can clip these amps before hitting the reference of 0 and the resulting compression is not easily detected.

I do not mind limiting my volume to -10 for music because that very loud.


This morning, I setup my OmniMic 2 to measure the volume while watching "Indiana Jones and the Last Crusade" with myRevel 5.1 system. Salons, Voice, Studios.

I turned off the Sub.


Normally, I would listen to a movie like this with the AV8801 at 54 (-34) but I decided to go a bit louder to 60 (-28).

During reasonably quiet scenes the reading at my seat (10 feet) was in the 60's.

Loud conversations would rise into to 70's.

Loud Action scenes rose into the 80's (barely)

The peak measured 104. In either table, that is loud.


To me this suggests that THX specs are reasonable for my use. 105 DB (excluding the .1 bass) is all I need for me to enjoy an action movie.

However, for most of the film the amps is cruising down in the 20 to 50 watt range.

At peak volume, pick your table, but It would be likely over 200 watts.

The 86 DB average seems high though because that is quite loud.


- Rich

Agreed on all points.
 
#197 ·
I have been attempting to provide data to help folks get a handle on how much power they actually need.

Sorry for the occasional typos gentlemen. The overriding point I wanted to make here is that Peak Volume is much larger than many realize.


I am not sure how much relevance the actual position on a volume know relates as the number is not a great indicator of power requirements for amps.

Most amps will obviously clip at 0 with speakers like mine that are in reality 2 watts for 86 DB into 4 ohms.


Moving right along with deference to the more learned among us here are some measurements in my room.

It is decent sized. 15x33 with 12' peaks. There is a 16 foot opening on the size and a 5 foot opening in the rear.

The signal path was: BDP-105 UDB DAC 7.1 Analog outs -> AV8801 Pure Direct Speakers set to large -> Parasound A51 amp -> Revel Salons.


The albums were: Sarah McLachlan Surfacing and Freedom Sessions and The House of Flying Daggers:

All measurements were taken with the OmniMIC 2 and a Radio Shack digital SPL meter.

SPL test.xlsx 9k .xlsx file


The minimum difference between the Radio Shack (Fast C-Weighted) measurement and the Peak measured by the OminMic was 12 DB.

If my math is right this time, that would be 20 times the power you would calculate with rom room measurements with a Radio Shack meter.


Also, not that with the volume at -10, the peak volume at 12 feet hit 107 DB.


- Rich
 

Attachments

#198 ·

Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23932990


I am not sure how much relevance the actual position on a volume know relates as the number is not a great indicator of power requirements for amps.


- Rich

On a properly calibrated system the MV reading tells us what we need to know in terms of power requirements. Well, that along with speaker sensitivity and listening distance. For example, if someone states they never listen beyond -15 on their calibrated system then they will need less power than say someone who listens at reference all other things being the same. So in this case, there would be no need to buy an amp capable of reference if it's not needed. All that being said, I would still recommend an amp that IS capable of clean power at reference.

Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23932990


Moving right along with deference to the more learned among us here are some measurements in my room.

It is decent sized. 15x33 with 12' peaks. There is a 16 foot opening on the size and a 5 foot opening in the rear.


- Rich

When it comes to satellite speakers you missed a critical measurement, listening position distance from the speakers. That's where our confusion started. Room dimensions are more useful for calculating listening room volume and subwoofer system requirements to properly pressurize that space.

Quote:
Originally Posted by RichB  /t/1418604/emotiva-xpr-5/100_100#post_23932990


Also, not that with the volume at -10, the peak volume at 12 feet hit 107 DB.


- Rich

Is that with or without subs?
 
#199 ·

Quote:
Originally Posted by duc135  /t/1418604/emotiva-xpr-5/180#post_23933391


On a properly calibrated system the MV reading tells us what we need to know in terms of power requirements. Well, that along with speaker sensitivity and listening distance. For example, if someone states they never listen beyond -15 on their calibrated system then they will need less power than say someone who listens at reference all other things being the same. So in this case, there would be no need to buy an amp capable of reference if it's not needed. All that being said, I would still recommend an amp that IS capable of clean power at reference.

When it comes to satellite speakers you missed a critical measurement, listening position distance from the speakers. That's where our confusion started. Room dimensions are more useful for calculating listening room volume and subwoofer system requirements to properly pressurize that space.

Is that with or without subs?


Listening distance was 12 feet.

The Salons were sent a full range signal in Pure Direct mode using the analog inputs.

All rips were from CD's, 2.0 with no sub.


- Rich
 
#201 ·

Quote:
Originally Posted by emofan21  /t/1418604/emotiva-xpr-5/100_100#post_24274831


Has any1 heard this AMP or any of the XPA amps woth GE Triton two speakers?? if so what where your thoughts??

Not the Tritons, but I've heard the 1st gen XPA-5, 1st gen XPA-2 and XPR-5 and compared all of them to my receiver and heard no audible difference until I went above reference level volumes on my speakers.
 
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