help on amp choice

[RichB]

Now I have a pair of focal 926 towers and looking to give them some good power. I feel like my anthem Mrx 300 runs out of steam at high levels during movies.

It might be.

With sensitivity of 91.5dB/2.83v/m, 60Wpc into 5 channel continuous (from official spec), 12ft distance, 5 speakers near the wall = 108dB SPL at listening position. (-3db if speakers away from boundaries)
THX recommends 85+20db peaks. So you're covered there.

Now if you like to damage the hearing, a 200Wpc amp with same environment would provide 113dB
Questions?

I agree with ADTG, 600Wpc amp would do nothing but allow OP to damage speakers/ears or both

Maybe the OP should just go get those XPA-1L's for the same money.

The Focals have impedance dips below 3 ohms, that will take current and the nominal 8 ohms may not tell the story.

They might be 4 ohms in critical areas where music and movies need the power.
The power calculator could be optimistic by 6 DB.

- Rich

 

[RichB]

On the other hand, there is this post on AVS about an XPA-2 with all caps leaking

http://www.avsforum.com/forum/90-receivers-amps-processors/781208-emotiva-thread-q-technical-talk-only-575.html#post29438026

- Rich

 

[BoredSysAdmin]

The Focals have impedance dips below 3 ohms, that will take current and the nominal 8 ohms may not tell the story.
They might be 4 ohms in critical areas where music need power. Add those together and the power calculation is optimistic
- Rich

Yes, focals 926 are rated with minimum 2.9ohm impedance, but with high sensitivity and rated nominal 8 ohm - I would guestimate that manufacturer is not far off truth. I have not been able to found independent measurements for the speakers.
That said I did find them for MRX 300 - http://www.soundandvision.com/content/anthem-mrx-300-av-receiver-ht-labs-measures
Which shows that 60wpc/5ch is quite underrated. I doubt many could notice even 1% distortion.

What I'm trying to say OP needs MARGINAL POSSIBLE improvement in amps section, maybe XPA-200. Anything over it = overkill

 

[RichB]

Yes, focals 926 are rated with minimum 2.9ohm impedance, but with high sensitivity and rated nominal 8 ohm - I would guestimate that manufacturer is not far off truth. I have not been able to found independent measurements for the speakers.
That said I did find them for MRX 300 - http://www.soundandvision.com/content/anthem-mrx-300-av-receiver-ht-labs-measures
Which shows that 60wpc/5ch is quite underrated. I doubt many could notice even 1% distortion.

What I'm trying to say OP needs MARGINAL POSSIBLE improvement in amps section, maybe XPA-200. Anything over it = overkill

Unless the impedance and phase angle traces are available, I would not put much stock in that 8 ohms nominal.
A high-phase angle at even a 4 ohm impedance will limit the power below its 4 ohm rating.

Focals are revealing and those distortion levels not that low. I also don't like the way it climbs the wall at the low end. That does not look good for those who believe the first watt should be squeaky clean.

Power into load may mater more than the absolute watts available but it correlates well with powerful amps.

All this may be moot, because when someone has the itch, sooner or later they scratch it

- Rich

 

[AcuDefTechGuy]

No, my argument is that sizing an amp is difficult and a musical peak can be tolerated by most speakers.
That may be a peak or an RMS number. If it is an RMS number than the crest is 3DB higher so the peak power would be 400-500 WPC peak.

If your speakers can handle the power, then give it to them cleanly. There are quality reasonably priced amps out there.
My argument is that if you can get an $750 amp that wont clip, that would hurt your speakers when using some common sense.
Buy an amp that is affordable that will not clip for that listener in their room.

AVRs are clip nicely these days, long before most listeners recognize distortion, they have failed to produce the power that the source material required. I can turn up my Yamaha A820 to where I know it is running out of gas, but it sounds ok.

Amps can include distortion limiters. Such a design will simply not produce the peak power, the more you turn them up the more the average power will increase but not the peaks. The result, power compression.
Some will never push their AVR to that level, but there is simply no way to easily determine at what point, with what source material that it occurs.

- Rich

There are significantly a lot more people who own just AVR than audiophiles who own separate amps. The people who own AVR don't have many issues of blowing their speakers like audiophiles who own separate amps. And the AVR people think it sounds great.

My argument is that people who own AVR don't have to worry at all about clipping. If the volume is turned up too loud, the AVR shuts down.

I've used the Denon 3312 for a few years now (without any kind of amps) driving various speakers for house parties and for loud KARAOKE. It sounds great.

Now it makes sense to add an external amp if your AVR shuts down in protection mode. It also makes sense to add an external amp just because you just want to.

But I don't think there is a good reason to buy a 500WPC amp when the speaker engineers recommend a max of 250W simply because you think the speaker somehow has a hypothetical peak requirement of 500W.

So what if the speaker requires 500W if the drivers are not made to handle that kind of thermal energy?

Like everyone says, physics is physics. You cannot exceed the thermal and mechanical limits.

My latest analogy to this is the human pain receptor feedback. We have physical limits. The minute we feel pain, we "shutdown". We don't need to take analgesics to suppress the pain in order to increase work.

If the speaker has a limit of 250W (pain threshold) and you give it 500W, you may get it to do more work, but you're not doing it any favors.

These speakers are NOT made for 110-120dB volume (work). If you need that kind of volume (work), buy some high efficiency speakers made for high output.

Anyway, that's my final rebuttal in this.

 

[RichB]

There are significantly a lot more people who own just AVR than audiophiles who own separate amps. The people who own AVR don't have many issues of blowing their speakers like audiophiles who own separate amps. And the AVR people think it sounds great.

True, smaller cheaper, and may be completely capable of satisfying the owner.

My argument is that people who own AVR don't have to worry at all about clipping. If the volume is turned up too loud, the AVR shuts down.

AVRs do not shut down because they are clipping, they will be likely be clipping when they shutdown. Any peak that requires more power than an amplifier can deliver will clip/distort the sound.

Now it makes sense to add an external amp if your AVR shuts down in protection mode. It also makes sense to add an external amp just because you just want to.

That it does.

But I don't think there is a good reason to buy a 500WPC amp when the speaker engineers recommend a max of 250W simply because you think the speaker somehow has a hypothetical peak requirement of 500W.

So what if the speaker requires 500W if the drivers are not made to handle that kind of thermal energy?

You a fan of the "The Audio Critic" and the power curve.
He opines that it is all about power into load. 2.9 ohms is a tough load and there is no telling how the Anthem handles it.

Like everyone says, physics is physics. You cannot exceed the thermal and mechanical limits.

My latest analogy to this is the human pain receptor feedback. We have physical limits. The minute we feel pain, we "shutdown". We don't need to take analgesics to suppress the pain in order to increase work.

If the speaker has a limit of 250W (pain threshold) and you give it 500W, you may get it to do more work, but you're not doing it any favors.

These speakers are NOT made for 110-120dB volume (work). If you need that kind of volume (work), buy some high efficiency speakers made for high output.

Anyway, that's my final rebuttal in this.

The volume level may require 150 watts into 2.9 ohms, an amp that delivers that is going to be oversized and not likely an AVR.
The absolute watts are not the issue. The only reason I suggested the XPR-2 was the OP has Emotiva and likes the brand, it fits the budget, and had a large transformer and capacitance not the absolute watts value.

If a user is going to turn up a system above its limits, an underpowered amp is not going to save it.

- Rich

 

[Hostility]

Wow just seen all the replys now I'm going to bail on the xpa1s as its just to much. I can get the xpa2 for a good price shipped that should last me years. The other choice is the xpa 200 but I just rather have a tiny bit overkill then not enough. Again I'm not sure where you guys find parasound in canada for cheap. And for bryston the used amps are still more money then a new emo

 

[PENG]

Wow just seen all the replys now I'm going to bail on the xpa1s as its just to much. I can get the xpa2 for a good price shipped that should last me years. The other choice is the xpa 200 but I just rather have a tiny bit overkill then not enough. Again I'm not sure where you guys find parasound in canada for cheap. And for bryston the used amps are still more money then a new emo

I bought mine at very competitive price, but the C$ was much higher at the time.

 

[AcuDefTechGuy]

If a user is going to turn up a system above its limits, an underpowered amp is not going to save it.

- Rich

Yes it will.

But it depends on the limit of the driver, how much under-power, and what kind of protection circuit it has.

As I've said before, if the tweeter driver limit is truly 150W, a 50W amp will NEVER produce enough power to exceed the 150W limit. Even if it clips, it could only theoretically produce 100W of clipped power, which is still 50W below the limit.

And in the case of the AVR, the AVR would shut down in Protection before the speaker is blown.

People need to understand that the CLIPPING itself does NOTHING to the driver. It is the increased power from the clipping that can damage the speaker. But when the amp clips, if the power is under the driver limit, the driver will NEVER be damaged.

Anyway, that's my understanding. But I'm not an engineer.

I want to know what the real ENGINEERS and speaker designers think!

PENG?

3dB?

Gene?

Dennis?

I know that Dennis has said in the past that a true high quality 100W amp can drive the Phil3 (4 ohm, 85dB/2.83v/m) to extreme high volume in a very large room.

 

[AcuDefTechGuy]

I mean really, most of us (there are the few exceptions ) will NEVER blow a speaker no matter WHAT amp we use because we understand that "consumer" or "audiophile" or "Hi-Fi" speakers are NOT made like "PA" speakers that are made to output 130dB volume outdoors.

Even if I used a 2000W amp, I would most likely NEVER blow my speakers.... unless I left my room unattended and some fool cranked up the volume all the way.

Most of the time, we use about 1-5W of power.

So when speaker engineers recommend 40W-250W, it's pretty accurate MOST of the time.

 

[RichB]

Yes it will.

But it depends on the limit of the driver, how much under-power, and what kind of protection circuit it has.

As I've said before, if the tweeter driver limit is truly 150W, a 50W amp will NEVER produce enough power to exceed the 150W limit. Even if it clips, it could only theoretically produce 100W of clipped power, which is still 50W below the limit.

And in the case of the AVR, the AVR would shut down in Protection before the speaker is blown.

People need to understand that the CLIPPING itself does NOTHING to the driver. It is the increased power from the clipping that can damage the speaker. But when the amp clips, if the power is under the driver limit, the driver will NEVER be damaged.

Sort of. Power compression changes the mix of power toward the high-end where the drivers cannot handle as much power:

"Why Do Tweeters Blow When Amplifiers Distort?"

http://sound.westhost.com/tweeters.htm

This is a short thread with a good read and a speaker designer too:

http://www.avsforum.com/forum/89-speakers/1737250-too-much-power-blown-tweeters.html#post28563794

Originally Posted by gman086 View Post
There was no clipping at all and I was always taught you can never have too much power and that it was too little power that caused speaker failure...

What you were taught was a myth. You can toast a tweeter with a low power amp pushed to clipping, which over-powers the tweeters, and you can toast a tweeter with a high powered amp that overpowers the tweeters. In either case they're over-powered and in both cases the voice coils will melt. Tweeters will usually warn of impending doom by sounding harsh, but not always.

- Rich

 

[AcuDefTechGuy]

Sort of. Power compression changes the mix of power toward the high-end where the drivers cannot handle as much power:

"Why Do Tweeters Blow When Amplifiers Distort?"

http://sound.westhost.com/tweeters.htm

This is a short thread with a good read and a speaker designer too:

http://www.avsforum.com/forum/89-speakers/1737250-too-much-power-blown-tweeters.html#post28563794

- Rich

It's a double-edged sword.

Excessive volume in a LOW power amp causes clipping which generates too much power beyond the driver LIMITS and kills the speaker.

Excessive volume in a HIGH power amp generates too much power beyond the driver limits and kills the speaker.

As the article says, "It is entirely possible to destroy drivers without ever letting the amp clip. Speaker systems rated for 200-500W almost always refer to peak power, and the average (or continuous) power rating is in reality as little as 10% of that claimed."

So a system rated for 250W max power may have average power rating of only 25W! Sending even 100W of average power (using a 300W amp) to the speaker due to excessive volume will blow the tweeter, midrange, and woofer!

A square-wave (severe clipping) has double the power of a sine-wave, so a 100W peak (sine-wave) amplifier can deliver 200W peak of a square-wave signal, regardless of harmonics and frequencies. Now the amount of AVERAGE power reaching the driver may vary with the harmonics and frequencies.

 

[PENG]

"Why Do Tweeters Blow When Amplifiers Distort?"

http://sound.westhost.com/tweeters.htm

I have a problem with that articles, it says "Most speakers are rated for a continuous power and an instantaneous power". That is simply not true. I would appreciate it if someone can show me a few speaker manufacturers website or their manuals that actually provide such specific information in a clear manner. In fact if I were to guess (but I won't), I would guess that more often than not the rated power provided are not "continuous". More than likely they are some sort of "defined" peak albeit not the "absolute" peak beyond which point damage would occur.

The rest of the article makes sense but let's be honest, using 100W average power is an extreme. I can listen to my 2 channel system at close to average 80 dB weighting C SPL sitting 6 meters from the speakers with average power of less than 1W. How many people would listen to average power of 10W let alone 100W? Even if they do, as the author of that article cited, the amp will deliver 100W during the 10 dB peaks and be at the onset of clipping. Even mid range AVR can do more than 100W into 8 or 4 ohms at less than 0.1% THD+N. So there isn't much of concerns of "compression" that Rich has been talking about.

IMHO, it is better to enjoy music than to worry about the theoretical compression or clipping that may damage tweeters. In terms of theory, surely I have to agree with Rich that either scenarios can put tweeters at risk. However, as everyone seems to agree, when "under powered" amps clip, one can hear the sound turning harsh, distorted at or near the point where the tweeters could be at risk. "Over powered" amps, would go further before the sound turns harsh and sound distorted. Overall, I believe higher power amps represents higher risk but as ADTG said before, at the end of the day it really is the owners who are responsible.

 

[RichB]

I agree that most AVRs are sufficient. However, the OP Focal's may be a harder to drive than most with a minimum impedance of 2.9 HZ.
I also agree that AVRs are well behaved when clipping, a musical peak can be simply limited and playback will continue flawlessly.

Simply plugging numbers into a power calculator does not take into account the speaker impedance and phase angle which limit the power delivery.
Also, room size which can mitigate the power requirements.

For me, this is not about speaker damage but sizing the amplifier so that peak power is supplied without clipping or limiting (soft clipping).
The OP asks a reasonable question and he may benefit from more capable amplification.

Anyone want to talk about the first watt?

- Rich

 

[PENG]

I agree that most AVRs are sufficient. However, the OP Focal's may be a harder to drive than most with a minimum impedance of 2.9 HZ.
I also agree that AVRs are well behaved when clipping, a musical peak can be simply limited and playback will continue.

Simply plugging numbers into a power calculator does not take into account the speaker impedance and phase angle which limit the power delivery.
Also, room size which can mitigate the power requirements.

For me, this is not about speaker damage but sizing the amplifier so that peak power is supplied without clipping or limiting (soft clipping).
The OP asks a reasonable question and he may benefit from a more capable amplification.

Anyone want to talk about the first watt?

- Rich

Debate on the theories aside, the specified 2.9 ohm minimum impedance with unknown phase angle vs frequency needs to be considered for sure. As such I recommended an amp for him in posts #2,4,& 8. I first recommended the A21, scaled back to A23 when he clarified his 2K budget limit. I believe the A23's rated 125W 8 ohms, 225W 4 ohms are honest and can handle the Focal Aria 926 in a medium size room.

Oh yes, I am concerned with the first watt, that's why I stick with the know quantities such as Parasound and Bryston, products I know operates in class A at low output. I am sure there are many other quality amps but for price the Halo A series are hard to beat.

 

[AcuDefTechGuy]

Wow just seen all the replies...

That's what happen when we talk about amps. One group says the difference in SQ of most amps is insignificant when level matched, one group says all amps sound significantly different. One group says more power is better (spend your money on an amp), one group says go with what the speaker engineers/designer recommends (save your money, you don't need an amp). This is how it will be forever.

IMO if you use an amp, make sure it has good speaker protection circuitry like the AVR, which has very good speaker protection.

I think that may be a reason why most people who only use AVRs don't complain about blowing their speakers - their AVRs shut down before bad things happen.

 

[Hostility]

Well I waited till cyber monday to see what emotivas limited edition amp was as the released it today and just ended up ordering the xpa-2 gen 2. I think for what I need it will do fine.

 

[RichB]

Well I waited till cyber monday to see what emotivas limited edition amp was as the released it today and just ended up ordering the xpa-2 gen 2. I think for what I need it will do fine.

Congratulations !

Please post your impressions.

- Rich

 

[Hostility]

Update -- Amp is coming 4 days earlier then the orig. ETA. so I'm happy about that. should see it monday!. Also went on a splurge and ordered the matching centre channel to my towers - Focal CC900. So both should be here monday. Then ill have to re run ARC and get it all sorted out but I'm hoping next weekend to do some nice tests. Going out to buy Godzilla and the new planet of apes movies on BD for test movies . I feel Xmas has come early!

 

[RichB]

Update -- Amp is coming 4 days earlier then the orig. ETA. so I'm happy about that. should see it monday!. Also went on a splurge and ordered the matching centre channel to my towers - Focal CC900. So both should be here monday. Then ill have to re run ARC and get it all sorted out but I'm hoping next weekend to do some nice tests. Going out to buy Godzilla and the new planet of apes movies on BD for test movies . I feel Xmas has come early!

Cool.

It is worthwhile to invest in a good center channel (the best that works in your system). Over 80% off all sound comes form that speaker:
This is a fun video talking about that and surround:

- Rich