Which Emotiva amp for stereo listening?

[Goliath]

I've read the 804s' demand quite a bit of power to do them justice. (correct me if my assessment is inaccurate).

People say the darnedest things.

 

[AcuDefTechGuy]

People say the darnedest things.

I think TLS Guy said that the B&W 800D needs at least 500 watts into 8 ohms for best sound.

 

[Goliath]

I think TLS Guy said that the B&W 800D needs at least 500 watts into 8 ohms for best sound.

I would love to know how he reached that number. Did he pull it out of a hat?

 

[fuzz092888]

I would love to know how he reached that number. Did he pull it out of a hat?

IIRC he never said that. The quote in question, if I have it right, was about TLS Guy talking about a friend of his. His friend had the 800D and the Mcintosh amplifier that it was hooked up to. Long story short, due to the low impedance dip of the 800D and the difficult phase angles he said that they need to be hooked up to a competent amplifier with a large current reserve. So unless the amp is class A, that usually means it's going to need to be pretty high power class A/B in order to have enough juice to push enough current. So 4-500 watts probably isn't too far off for most class A/B amps.

 

[Goliath]

So unless the amp is class A, that usually means it's going to need to be pretty high power class A/B in order to have enough juice to push enough current. So 4-500 watts probably isn't too far off for most class A/B amps.

The chances of those speakers needing 4-500 watts at any typical volume level is very, very slim. The speakers have an impedance minimum of 3.15 ohms at 91Hz, 3.1 ohms at 620Hz, and 3.67 ohms at 21kHz.

Sensitivity is 90.2dB(B)/2.83V/m. Now if one requires 115 dB, seated 5-6 meters back, listening to music that has lots of energy centered at frequencies where the impedance is at a minimum, then fair enough, your demands for power increase quite substantially.

However there is no evidence whatsoever that you need 4-500 watts under typical conditions - ie not 115 dB SPL. It's just another arbitrary number that people throw in the air - you need "x" wattage in order for these speakers to "strut their stuff". If we don't qualify the claim at a specific SPL then the claim is devoid of any meaning, and since the SPL kinda has some influence over how much voltage and current the speaker will ultimately draw, it kinda is a little pertinent, wouldn't you agree?

If you listen at 95 dB peaks and sit 4 meters away then you need around 30 watts of power, excluding room gain. Let's double that, to give us additional headroom in case those nasty low impedance dips appear, so 60 watts. If you add another 440 watts to hit that same 95 dB peak, do you think the amplifier would deliver 440 watts, or still deliver 60 watts?

Just about any amplifier can drive any low impedance load - it's a question of volume level. I've driven a number of different speakers with a nominal 4 ohm impedance with an AVR to levels I find comfortable without any issues. So ignoring atypical conditions for a moment, why would any reasonable person in a reasonable room size, seated reasonable distances, at reasonable SPL, require 500 watts for these speakers? I would love to understand the reasoning behind this.

 

[AcuDefTechGuy]

90dB/2.83v/m, min impedance 3 ohms, 12ft (3.6m) distance, Total Peak volume 105dB in 2.0 (2 speakers, no subs) Pure Direct mode.

That means each speaker needs ~ 200 watts into 8 ohms, ~ 400 watts into 4 ohms, & ~ 500 watts into 3 ohms.

My total peak 2.0 volume from 3.6m is 94 dB, so each of my speakers only needs 16 watts into 8 ohms, 32 watts into 4 ohms, & 42 watts into 3 ohms.

My 85dB/2.83v/m/4 ohms Phil3s are powered by a Denon 3312 to 94dB (2.0 mode), which means 50 watts/8 ohms & 100 watts/4 ohms.

I try not to exceed OSHA limits on SPL.

 

[AcuDefTechGuy]

So unless the amp is class A, that usually means it's going to need to be pretty high power class A/B in order to have enough juice to push enough current. So 4-500 watts probably isn't too far off for most class A/B amps.

So how much power is required for a class A amp?

I didn't think the class of the amp mattered? Always thought power is power; Power = Voltage x Current (amps).

All homes have parallel circuits, which means the voltage is constant.

4 ohms/ 200 watts/ 28 volts/ 7 amps
8 ohms/ 100 watts/ 28 volts/ 3.5 amps

But if the amplifier is driving the same load/ impedance (say 4 ohms), then 200 watts/7 amps = 200 watts/7 amps? Wouldn't both 200 watts have the same current?

I mean for all amps (no matter the class) to produce 200 watts, wouldn't they all require 7 amps of current if they both drive the same 4 ohms load & the voltage is constant?

 

[RichB]

According to Stereophile the Salons required 2 watts to achieve their sensitivity rating because below 600hz they are 4 ohms speakers.
I have a decent size room and been through the calclators etc and it is a wash so I will go with the 2 watt number.

Under normal conditions, I listen under 80 DB so that is a watt

My goal is to always have the power required so the amp does not compress the sound.
If you go by THX 85 DB with 20 DB headroom, so this requires 100 times the power or 200 watts.

- Rich

 

[AcuDefTechGuy]

According to Stereophile the Salons required 2 watts to achieve their sensitivity rating because below 600hz they are 4 ohms speakers.
I have a decent size room and been through the calclators etc and it is a wash so I will go with the 2 watt number.

Under normal conditions, I listen under 80 DB so that is a watt

My goal is to always have the power required so the amp does not compress the sound.
If you go by THX 85 DB with 20 DB headroom, so this requires 100 times the power or 200 watts.

- Rich

And whether it is a class-A, A/B, D, G amp, the Salons require the same power?

 

[AcuDefTechGuy]

I think the bottom line is, yes, given extreme crazy deafening detrimental volume level (or very far distance), most speakers will require a lot of power.

But most of us are pretty sensible and still healthy and we will not risk our hearing. So bottom line, our speakers will not need all that high power.

And so no speaker, B&W 800 or Salon2 or whatever, needs 400 - 500 watts into 8 ohms to sound great if we do not exceed OSHA SPL limits in fear of damaging our hearing.

 

[fuzz092888]

The chances of those speakers needing 4-500 watts at any typical volume level is very, very slim. The speakers have an impedance minimum of 3.15 ohms at 91Hz, 3.1 ohms at 620Hz, and 3.67 ohms at 21kHz.

Sensitivity is 90.2dB(B)/2.83V/m. Now if one requires 115 dB, seated 5-6 meters back, listening to music that has lots of energy centered at frequencies where the impedance is at a minimum, then fair enough, your demands for power increase quite substantially.

However there is no evidence whatsoever that you need 4-500 watts under typical conditions - ie not 115 dB SPL. It's just another arbitrary number that people throw in the air - you need "x" wattage in order for these speakers to "strut their stuff". If we don't qualify the claim at a specific SPL then the claim is devoid of any meaning, and since the SPL kinda has some influence over how much voltage and current the speaker will ultimately draw, it kinda is a little pertinent, wouldn't you agree?

If you listen at 95 dB peaks and sit 4 meters away then you need around 30 watts of power, excluding room gain. Let's double that, to give us additional headroom in case those nasty low impedance dips appear, so 60 watts. If you add another 440 watts to hit that same 95 dB peak, do you think the amplifier would deliver 440 watts, or still deliver 60 watts?

Just about any amplifier can drive any low impedance load - it's a question of volume level. I've driven a number of different speakers with a nominal 4 ohm impedance with an AVR to levels I find comfortable without any issues. So ignoring atypical conditions for a moment, why would any reasonable person in a reasonable room size, seated reasonable distances, at reasonable SPL, require 500 watts for these speakers? I would love to understand the reasoning behind this.

First, we all know the numbers for raw SPL. It's not always that simple and you completely left phase out of your above musings. Second, you completely missed the point of what I said. re-read it and if you don't get it simply ask. If you understood what I was getting at, you would know that 4-500 watts really is unimportant except for what the rating generally means the amp has. Which I also mentioned that Dr. Mark mentioned.

So how much power is required for a class A amp?

I didn't think the class of the amp mattered? Always thought power is power; Power = Voltage x Current (amps).

All homes have parallel circuits, which means the voltage is constant.

4 ohms/ 200 watts/ 28 volts/ 7 amps
8 ohms/ 100 watts/ 28 volts/ 3.5 amps

But if the amplifier is driving the same load/ impedance (say 4 ohms), then 200 watts/7 amps = 200 watts/7 amps? Wouldn't both 200 watts have the same current?

I mean for all amps (no matter the class) to produce 200 watts, wouldn't they all require 7 amps of current if they both drive the same 4 ohms load & the voltage is constant?

I'd have to ask my cousin as he's the physics teacher. FWIW the Threshold S/300e I have has about the same current rating as a Parasound HCA-2200II which is rated at 100 WPC more than the Threshold at 8 ohms.

 

[ImcLoud]

According to Stereophile the Salons required 2 watts to achieve their sensitivity rating because below 600hz they are 4 ohms speakers.
I have a decent size room and been through the calclators etc and it is a wash so I will go with the 2 watt number.

Under normal conditions, I listen under 80 DB so that is a watt

My goal is to always have the power required so the amp does not compress the sound.
If you go by THX 85 DB with 20 DB headroom, so this requires 100 times the power or 200 watts.

- Rich

200 watts seems to be the "magic" number, I have a large front parlor where my 2.2 evo2 system is located, and before I received my xpa2 I ran the system with my upa200. Trying to fill the room with sound with the towers crossed to the subs at 80hz it was clipping.... I installed the xpa2 and NEVER clipped again {I don't think I can come close to}, I have also tried my bk 200.2 in there and no clipping, I have all tried my marantz avr {I believe 80w pc} and its lost in there {also for some reason sounds terrible at low volumes, but that is another story}...

So unless the speakers are sitting rite in front of you in a medium to small sized room, 200w is a good starting point, when the speakers are close to the lp, then all bets are off, my 2.1 pc system will drive you from the room if you turn up the miniX past half way...

Anyway, outlaw 2200's IMO would power pretty much any speaker especially when crossed to a sub, so for $550 B stock, you can have a pair of capable mono blocks and be done with it...

Check their bstock page, they come and go quite often, also I have bought them a couple times and if they have one bstock and you buy two, you get 1 brand new and one bstock, I once got two brand new for bstock price, score.... {although I have never had a bstock problem...}

 

[Irvrobinson]

So how much power is required for a class A amp?

I didn't think the class of the amp mattered? Always thought power is power; Power = Voltage x Current (amps).

All homes have parallel circuits, which means the voltage is constant.

4 ohms/ 200 watts/ 28 volts/ 7 amps
8 ohms/ 100 watts/ 28 volts/ 3.5 amps

But if the amplifier is driving the same load/ impedance (say 4 ohms), then 200 watts/7 amps = 200 watts/7 amps? Wouldn't both 200 watts have the same current?

I mean for all amps (no matter the class) to produce 200 watts, wouldn't they all require 7 amps of current if they both drive the same 4 ohms load & the voltage is constant?

Amps vary in efficiency, where efficiency is defined as the ratio of AC input watts to output watts. Some Class D amps for subwoofers claim to be over 90% efficient. Real, actual Class A amps with all-discrete balanced driver stages and balanced differential output stages (which some people call quad differential) can be quite inefficient, in the range of 40-50%, depending on how many amplification stages there are, whether there are fans, etc.

 

[Irvrobinson]

So how much power is required for a class A amp?

I didn't think the class of the amp mattered? Always thought power is power; Power = Voltage x Current (amps).

All homes have parallel circuits, which means the voltage is constant.

4 ohms/ 200 watts/ 28 volts/ 7 amps
8 ohms/ 100 watts/ 28 volts/ 3.5 amps

But if the amplifier is driving the same load/ impedance (say 4 ohms), then 200 watts/7 amps = 200 watts/7 amps? Wouldn't both 200 watts have the same current?

I mean for all amps (no matter the class) to produce 200 watts, wouldn't they all require 7 amps of current if they both drive the same 4 ohms load & the voltage is constant?

Or did I misunderstand you in my last post? If we're talking about power on the speaker cables, then the Class of the amp is absolutely irrelevant. It is in vogue for some high-end companies to rate their amps for huge peak currents, and Threshold was one of the guilty parties in the 1980s-90s. Mostly it's baloney, if that's what you're talking about.

 

[Goliath]

First, we all know the numbers for raw SPL. It's not always that simple and you completely left phase out of your above musings.

If we don't know the conditions in which the speakers will be used then I'm sure you can agree that throwing some arbitrary wattage figures around isn't going to shed light on anything useful or relevant.

 

[PENG]

If we don't know the conditions in which the speakers will be used then I'm sure you can agree that throwing some arbitrary wattage figures around isn't going to shed light on anything useful or relevant.

I have to agree with you on this. My room is small to medium by THX standard and with my speakers and my listening habbit I only need fractional watts with peaks to 20W or 30W at the most. For someone sitting 6 meters away in a 20X30X10 room, listen at 85dB on average, to music contents that has frequent 20 dB dynamic peaks and wish to assure his amp will never clip, then he is going to need thousands of watts, probably half a dozens of Mc2kW McIntosh monoblocks each fed off its own dedicated 30A circuit.

Oh, almost forgot, I am not sure which home use speaker can handle thousands of watts of peaks. The 800 Diamond probably may be able to handle a little more than 1 kW but much more than that would likely fry the diamond tweeter in no time. So that means we also need to run 3 pairs of them, each pair to be driven by a pair Mc2kW and I only hope that should do the trick.

Back to reality and I am glad I am in a small room and am happy with merely the same kind of SPL that I experienced in a typical live classical music (listening to concertos and symphonies) concert hall.

 

[PENG]

I'd have to ask my cousin as he's the physics teacher. FWIW the Threshold S/300e I have has about the same current rating as a Parasound HCA-2200II which is rated at 100 WPC more than the Threshold at 8 ohms.

I bet the physics teacher will agre with Irv, his 2nd post#34, not the one before. Phase will affect the current/watt relationship but the math applies just the same regardless of class A or A/B, on the output (speaker) side, and I think that was ADTG's point.

 

[AcuDefTechGuy]

Anyway, outlaw 2200's IMO would power pretty much any speaker especially when crossed to a sub, so for $550 B stock, you can have a pair of capable mono blocks and be done with it...

Yeah, but are they ($550 B-stock 2200 pair) any better than a $300 brand new Harman Crown XLS1000 stereo amp that can output 215W into 8 ohms/350W into 4 ohms/550W into 2 ohms? I doubt it.

 

[ImcLoud]

Yeah, but are they ($550 B-stock 2200 pair) any better than a $300 brand new Harman Crown XLS1000 stereo amp that can output 215W into 8 ohms/350W into 4 ohms/550W into 2 ohms? I doubt it.

ohh yeah they are, lol... I own an xls1500 and I use the outlaws, and bought the crown after, but that is in its box.. It is a great amp for sure, they sound just like, well nothing, which is what you want... BUT they dont have 12v triggers, they have fans that I can hear {granted they are super quiet}, line level voltage issues {not a deal breaker of course}, then the whole class D and tweeter issues {wether its true or not, who knows} and they are ugly, the lights are BRIGHT as the sun, the chassis are "pro" quality, its just pro gear. So sound is important but honestly if I had to choose between the two sound wise-- I have to say the 2200's win, they are mono blocks which I like, they are made for "home audio" which I like "they have a single light that matches my 2200's light {I like that too}, they get controlled by my preamp, they have good warranties, good cs, great sq, the differences add up fast....


Don't get me wrong the pro amps are awesome and they have come a long way and I like them, but they have there place, and in a nice "pretty" 2.2 audiophile-ish setup isn't it... not for me anyway.... Now, if you have a pair of passive subs or a pair of cerwin vega 215's sure grab some of the xls amps and get crazy, but when you are trying to build somthing classy and aesthetically pleasing, spend the extra $250 and get the rite stuff....

Now don't jump down my throat, I am not saying class d is bad, I have threads around here where I say I love class D, I like pioneers d3 stuff a lot, and wish they would come out with some multi channel units at a good price and flip the business on its ear, but for some reason its not happening, when I spoke to my local pioneer service center about the d3 stuff, he did tell me they had more service isuues than any other pioneer unit, so maybe that is the issue, but what ever it is it is...


I personally prefer class a/b mono blocks for 2 channel music listening, just my preference, not saying anyone elses preferences are wrong, just them are mine...

 

[RichB]

I ran some tests using a Radio Shack and OmniMic to measure the SPL of music on my Parasound A51 / Revel Salon system.
The numbers surprised me. The music far greater peak volume that you would know using the RS meter. It missed peak volume from 10 to 13 DB.
If you think a slow meter can tell you how loud the peaks are you only be off by 10 to 20 times the power.

I started the thread and donned me flame suit

http://forums.audioholics.com/forums/amps-pre-pros-receivers/87598-you-running-out-amplifer-power-i-am.html#post997677

- Rich