Monoblocks for theater?

[Matthew J Poes]

I’m really curious why you all believe so strongly that this would matter for 2 channel more than surround? It feels like movies are being treated as second rate to music in terms of sound quality or the need for channel separation. If so (and I don’t want to put words in the mouth of others) I think I would tend to disagree. I think channel separation is important for all things sound using more than one speaker. That it’s just as important for surround sound. The only reason I think it’s less important for surround sound speakers is that he surround channels typically have a lot of overlap already and frequently aren’t full range in the mixes, limiting the benefit of the fully independent amplifier channels. Add in that most surround processors use premium DACs on the fronts but cheaper multichannel DACs on the surrounds and any benefit seems to be lost (this is even true of the Emotiva and oppo).

However as a sound format I think movies are as in need of the best audiophile sound tricks as music. Movies are encoded on Blu-ray in one of two lossless formats at 24 bits and typically 96khz or even sometimes 192khz. The dynamic range of movies typically far exceeds that of music because we seem to like big dynamics in movies but not music (thanks loudness wars I hate you too). Research into object based audio and the creation of 3D soundfields has even shown that very directional discrete sound sources are necessary for the greatest realism which to me would highlight the importance of good channel separation. Even the fact that most receivers of good quality maximize the physical distance between the left center and right amplifier channels and use mono dac arrangements for the main channels shows the technical importance of high channel separation.

My point being I would not be so quick to dismiss audiophile sound in movies. The source format is superior to what is most commonly used for music (red book cd) and the need is just as great.

 

[Tony V.]

I dont think anyone is discounting the need for good channel separation, I think the question here is "Is the juice worth the squeeze"? Mid to high end receivers do a fine job with separation. Running a dedicated two channel amp for the mains and maybe one for the center channel and your good to go. I would challenge anyone to actually hear a difference when using monoblocks as long as the amps have enough headroom there should be no audible difference.

 

[Matthew J Poes]

I dont think anyone is discounting the need for good channel separation, I think the question here is "Is the juice worth the squeeze"? Mid to high end receivers do a fine job with separation. Running a dedicated two channel amp for the mains and maybe one for the center channel and your good to go. I would challenge anyone to actually hear a difference when using monoblocks as long as the amps have enough headroom there should be no audible difference.

It was my impression that some maybe thought this juice was worth the squeeze for music but not movies. I was making the point that I don’t think that is true.

If dynamics is the only concern, movies are far more dynamic than music. Average music dynamics is about 10db peak from average sound level and a total of maybe 30-40dbs of full dynamic swing. Movies are typically 30dbs of dynamic range from average voice to peak and closer to 100dbs full dynamic swing. Movies also so this across many more channels this drawing a lot more power.

 

[AudioThesis]

I disagree that ANY receiver does a good job at separation, but they are probably fine for the job. The thing is, monoblocks aren't even a necessity for 2 channel. They can provide further details due to multiple factors, but the OP has a GREAT amplifier already and I see many more areas to improve before looking at the amp.

The truth is, something like monoblocks play a bigger role in a 2 channel system because the music takes 100% of your attention. In a theatrical setting, the visuals take a huge chunk out of that and minor improvements, while they may be noticeable, might not be impactful in the overall experience. To me, the ability to localize a speaker is a bigger issue than anything else, and that starts at the speaker.

We all play the game a different way.

 

[AudioThesis]

It was my impression that some maybe thought this juice was worth the squeeze for music but not movies. I was making the point that I don’t think that is true.

If dynamics is the only concern, movies are far more dynamic than music. Average music dynamics is about 10db peak from average sound level and a total of maybe 30-40dbs of full dynamic swing. Movies are typically 30dbs of dynamic range from average voice to peak and closer to 100dbs full dynamic swing. Movies also so this across many more channels this drawing a lot more power.

If he had a similarly impressive amplifier in 2 channel, I would still say his amp was fine and to look in other areas. The point is the amp is not his weak point.

As an aside, if you have your speakers cut off at 80 hz, how much power do you really think they need?

 

[Tony V.]

I think the choice in speakers would be a far more crucial decision than weather to go with monoblocks or something else.
Efficient speakers would also be a better choice if your looking for good separation as a speaker that has wide swings in its efficiency would demand a much better amp with much better headroom (but again we are not talking 1000watts of headroom just 100 watts extra would be plenty.

 

[Matthew J Poes]

If he had a similarly impressive amplifier in 2 channel, I would still say his amp was fine and to look in other areas. The point is the amp is not his weak point.

As an aside, if you have your speakers cut off at 80 hz, how much power do you really think they need?

Skip, I don't want to put words in your mouth so understand I'm using your question to make a general point, not attacking you at all. Your question is commonly asked, how much power do you really need. There is a huge, let me say it again to reinforce, HUGE misconception that you do not need all that much power for movies with average speakers as long as they aren't reproducing bass.

Usually the wisdom goes something like this: Bass has more area under the curve therefor it needs more power to reproduce. It takes more energy to move a heavy cone at low frequencies than it does at high frequencies. Sometimes its as simple as "Bass uses more power than mid and high frequencies". None of this is accurate without some qualifications, and in general, it's best to just consider it inaccurate.

The amount of power it takes to produce a given frequency at a given level depends on its efficiency. If a woofer has equal efficiency at 20hz as it does at 3000hz, then it takes exactly the same amount of power at 20hz as it would at 3000hz. Highpassing it doesn't add headroom because you have removed the power heavy low frequencies. It actually adds headroom because it frees up power to produce the very power hungry mid frequencies.

Sound is power agnostic in terms of volume, what determines the power hungry nature of a speaker is its efficiency, and of a system is the content. Since movies and music have the greatest area under the curve, so to speak, in the midrange, it is actually midrange that is most power hungry.

Highpassing does add headroom, but this is because it takes more power to produce two tones at 25 watts than one tone at 25 watts. Complex musical signals thus would require a lot more power than what you would guess looking at just a signal tone power draw. The SPL peak calculators assume a signal with equal power under the curve and not a complex signal, which would actually reduce the power. What this means is that the power estimate I give is conservative, you could probably get away with less in the real world.

Now we go back to movies and standards to answer this question accurately. The standard for home theaters (often quoted as THX but in fact adopted by many companies and standards groups like ITU) is that a main speaker should reproduce cleanly (without excessive distortion) 105db's. That is not across all mains (I've seen this misconception) but just a single main. That is at the listening position. The subwoofer must produce 115db's at the same listening position, but for this discussion, we will ignore that for now.

The average sensitivity of a domestic speaker is about 85 db's. To reach reference levels with a 12 foot listening distance and still have a small amount of headroom it would require 3100 watts per speaker (3db's of headroom to avoid clipping). To do this without headroom (let's say since this is a peak we don't need that headroom), it would still take about 1700 watts (that would give us enough headroom to avoid any clipping at 105db's (.5db's headroom).

With a speaker that has a sensitivity of 88db's, 900 watts with no headroom.

91dbs, 450 watts

95db's, 180 watts

Now we have a few issues. First, most manufacturers are not so honest about their speaker sensitivity ratings. its often a good 2-3db's lower.

Another issue we see is that even with highly sensitive speakers the amplifier requirements per speaker is much higher than the amplifier can produce that most people own, such as in receivers.

Now a lot of people reply to this by saying they would never listen at 105db's, but that is missing the point. 105db's is the momentary peak (those moments have gotten pretty long in movies like Star Wars) that the system produces when voices are at around 75db's. That IS actually a pretty comfortable listening level for voices.

Oddly enough I just found an article talking about the loudness war coming to cinema's. Apparently movie soundtracks are being encoded at louder average levels, sometimes the 30db of dynamic range between 75db's and 105db's is maintained such that the peaks are still just 105, and sometimes they aren't. Supposedly this hasn't translated to the soundtracks on blurays yet, but I honestly question that. It seems to me like some movies have gotten, on average, louder. If nothing else, the amount of time the movie is playing at elevated levels seems longer.

I usually make this point for a different reason than we are talking here, which is that most domestic speakers connected to a receiver cannot reproduce reference levels as they are meant today. The only way that the THX rated speakers with THX rated receivers could do that was by making them 4 ohm speakers (to increase the receiver amplifier output) and relying on multiple speakers playing at the same time (which is not how the standard was defined and so not the headroom that the engineer is playing with). The reality is if you want a system that can truly hit reference levels cleanly, it is very likely that you need WAY more power than most people have and probably much more sensitive speakers. Thankfully most of us don't want to listen that loud and are totally happy with the status quo. For those who want a 1000hp Corvette, that isn't the case. That is why JBL Pro cinema speakers became so popular in homes. It is a small part of the reason why I like JTR speakers, JBL M2's, or my own Gedlee's.

So the short answer to Skip's question is that, amazingly, if you want the headroom to reproduce a movie soundtrack as the director intended, you probably need well over 1000 watts per channel.

 

[Tony V.]

Im going to have to try and find the article but a while ago I found someone who had tested different sounds through speakers (not test tones) and one finding was that using full range speakers that were 88db efficient running at reference level using a snare drum hit as the sound drew 230watts momentarily. A snare drum "thwack" has very little if any information below 80Hz but clearly still required a fair amount of juice to reproduce it.

 

[Talley]

Thats exactly right. 105db for a single speaker cleanly. I can't hit that with my current setup. I can only hit around 98-101ish. Still we are talking peaks... I never really measure peaks. Maybe i can I'm not that die hard to figure out.

don't forget room gain too... that will help some. Moving to something like those JTR someone just told me about that is 4ohm and 95+db sensitive that really makes it easy to get to those levels.... all of a sudden an amp will now have more output due to the 4ohms and 98db would mean somewhere around 112db or so at 12'. Plenty of headroom and realistic dynamics.

I read an article awhile back that realistic dynamics one of the hardest things to reproduce that took many watts was a simple snare drum. on teh system with 88db senstive speakers it took 600 watts at 4 ohms to reproduce those instantaneous dynamics of a peak hit.... not sustained... just peak. Many amps clip during this and just have a split of distortion but most don't know any better because it's so fast and they've never heard a setup that does.

Again... what I've read. I'd have to actually experiment to confirm of course.

 

[Talley]

Im going to have to try and find the article but a while ago I found someone who had tested different sounds through speakers (not test tones) and one finding was that using full range speakers that were 88db efficient running at reference level using a snare drum hit as the sound drew 230watts momentarily. A snare drum "thwack" has very little if any information below 80Hz but clearly still required a fair amount of juice to reproduce it.

I wonder if it was the same article i read... I thought it was 600 watts

 

[Tony V.]

So the short answer to Skip's question is that, amazingly, if you want the headroom to reproduce a movie soundtrack as the director intended, you probably need well over 1000 watts per channel.

Keep in mind an amp even though rated for say 200watts can produce well over that momentarily likely 3 times as much "IF" it has the power supply to drive it. Most good dedicated multi channel amps can do this.

 

[Tony V.]

I wonder if it was the same article i read... I thought it was 600 watts

Maybe the same article but it was not 600 I can assure you that.

 

[Matthew J Poes]

I disagree that ANY receiver does a good job at separation, but they are probably fine for the job. The thing is, monoblocks aren't even a necessity for 2 channel. They can provide further details due to multiple factors, but the OP has a GREAT amplifier already and I see many more areas to improve before looking at the amp.

The truth is, something like monoblocks play a bigger role in a 2 channel system because the music takes 100% of your attention. In a theatrical setting, the visuals take a huge chunk out of that and minor improvements, while they may be noticeable, might not be impactful in the overall experience. To me, the ability to localize a speaker is a bigger issue than anything else, and that starts at the speaker.

We all play the game a different way.

"separation" to me is not a subjective term though. It's a term referencing the technical concept of cross-talk. Cross-talk is objectively measurable. Receivers have very low cross-talk. The channel separation values are typically very good. There haven't been the kind of subjective studies we need to really understand this in my opinion, but most that I can find seem to suggest that somewhere between 70 and 100db's of separation is needed to be transparent (The original number was 30db, but more recent research suggests that crosstalk in surround formats impacts intelligibility and image placement). In other words, where we can no longer hear the difference between infinite separation and this value. That cross-talk at higher frequencies is more acceptable because our ears are less sensitive, which is good because all electronics that share a chassis have crosstalk at high frequencies, meaning all dacs and preamplifiers along with many/most amplifiers. I'm not saying a receiver equals the best audiophile gear, but it is supposedly so good as to be transparent.

If we accept the lower bound of the range I gave, 70db's, then all receivers made today meet that number. If we want to argue the higher value (or even higher values) are needed, then certainly there are no receivers that can achieve that.

Here are some example measurements:

https://www.soundandvision.com/content/marantz-sr7011-av-receiver-review-test-bench
Marantz SR7011=71db's or so
https://www.soundandvision.com/content/yamaha-aventage-rx-a3060-av-receiver-review-test-bench
Yamaha RX-A3060=79db's or so
https://www.soundandvision.com/content/arcam-avr850-av-receiver-review-test-bench
Arcam AVR850=101db one way, 88db the other
https://www.soundandvision.com/content/ati-at527nc-and-at524nc-amplifiers-review-test-bench
ATI AT527nc amplifier=115db
https://www.soundandvision.com/content/onkyo-pr-rz5100-surround-processor-review-test-bench
Onkyo PR RZ5100 processor=98db
https://www.soundandvision.com/content/rotel-rap-1580-surround-amplified-processor-review-test-bench
Rotel RAP-1580 receiver 88db

Audiophile Gear:
https://www.stereophile.com/content/lamm-industries-l21-reference-preamplifier-measurements
Lamm l21 Preamplifier >110db's at all frequencies, >120db's at 1khz.

I would post more, but honestly, nearly everything I looked at on Stereophile that was competent was about the same.

There are "audiophile" products that are exceptions, but then, I already mentioned that most research seems to suggest that anywhere from 30db's to 100db's is more than good enough, with 70-100 being a good conservative value.

https://www.stereophile.com/content/octave-audio-v-80-se-integrated-amplifier-measurements
This Octave Audio V80SE integrated amp is just 70db's of channel separation, on par with the receivers.
Skip, my guess is that integrated amp that you and I listened to together is inline with this, but I honestly think it didn't compromise the sound staging in an obvious way.

https://www.stereophile.com/content/classé-sigma-2200i-integrated-amplifier-measurements
This Classe Sigma integrated amp is about 80db's in the worst case

Just one thing to add, cable dressing is critical to channel separation. The causes of cross-talk are numerous and one of them is capacitive and inductive coupling. If you twisted your cables together you may have created some inductive coupling. More likely, you may have them bundled together. If they do not have sufficiently thick insulation, you can create capacitive coupling that will cause cross-talk and this would get worse at high frequencies. I've never really measured this over long distance to see how this plays out, but when I built a bunch of amplifiers I did measure this. I found that bundling the cables together caused the cross-talk to go to hell. In my final designs I ran the cables in a 3D grid such that they were physically very far apart and oriented away.

 

[Tony V.]

Found the article with the tests
http://www.cordellaudio.com/he2007/show_report.shtml

 

[Matthew J Poes]

Keep in mind an amp even though rated for say 200watts can produce well over that momentarily likely 3 times as much "IF" it has the power supply to drive it. Most good dedicated multi channel amps can do this.

I've heard this argument used as a claim for not really needing the RMS value to be that high, but a few things to keep in mind. While it is true an amplifier can momentarily put out more power, the distortion level may be very high and the amplifier may be clipping. Amplifiers can't put out 3 times their RMS rating for 1 second without clipping, it isn't quite that good.

There are so many arguments on peak output measurements that I don't feel confident even trying to quantify it. What I've been told is that its better to pick amplifiers that have an RMS rating that is where you need to be. It's the safest bet. I'm not suggesting we all need 3000 watt amplifiers, just that assuming a 100 watt per channel receiver will produce 300 watts per channel on demand for a momentary peak is probably a step too far.

The other issue is that most average speakers are so far off the mark to hit reference levels that a 200 watt amp producing 3 times its power still isn't enough. The average speaker has an efficiency of 85-88db's and a power handling under 200 watts. In a normal room that won't hit 105db's.

As I said, in practice this isn't such a huge issue as most soundtracks are designed to energize most if not all of the speakers and the engineers often are still trying to keep the total level in the room to 105db's, meaning that we can rely on all the amps and all the channels to help out. That isn't what reference level means, but it is what it has become in practice.

There is a good argument being made that true reference level as it was defined by ITU is such that theaters have become dangerously loud and that home theaters with high output capability would become equally dangerous. The standard says 105db's for EACH speaker! That means in a modern 11 channel system, if each could produce 105db's, then we are now looking at 115db's in room output at the 12 foot listening distance. Probably more since we would not likely be an equal 12 feet from every speaker, and so some of the sources would be somewhat (much) louder.

 

[Matthew J Poes]

Found the article with the tests
http://www.cordellaudio.com/he2007/show_report.shtml

That looks like a neat event.

I wouldn't say their finding is any different than what I suggested. They used music, music doesn't have the dynamic range of movies. They said most amps have between .5db and 3db of headroom. I would say a receiver is on the low side of that, but in either case, that means a 200 watt amplifier could produce 400 watts if it had 3db's of headroom for short bursts.

I'm not a great amplifier measurer and had someone who is criticize my own RMS meter approach which uses the same assumptions as Cordell's meter. In any case, it isn't clear how they are looking at distortion with that. When I did my own, I found most amps never exceeding 3db's of headroom and doing so for only very brief moments. The design criteria that most affected this was the amplifiers own power dissipation capability. If the amplifier was able to dissipate 400 watts (and lets pretend its 100% efficient) and it's voltage supply allows it to produce 400 watts at 4ohms, then its 4ohm headroom is 0dbs. That same amplifier into 8 ohms might have 3db's of headroom if the supply voltage can be changed. Typically that isn't true so you get more like 1.5db's. This is very close to how most receivers are built.

I still stand by my view that most people don't have anywhere near enough amplifier power to meet the dynamic peaks of movies or movies without clipping.

 

[Matthew J Poes]

I think the choice in speakers would be a far more crucial decision than weather to go with monoblocks or something else.
Efficient speakers would also be a better choice if your looking for good separation as a speaker that has wide swings in its efficiency would demand a much better amp with much better headroom (but again we are not talking 1000watts of headroom just 100 watts extra would be plenty.

This I fully agree with Tony and is why I suggested speakers earlier. The sound quality difference of better speakers certainly outweighs the sound quality difference of better amps. More importantly, if trying to create a system with more dynamic reserves, the speaker is typically the area to focus on. While most speakers can handle a lot more power over a short period of time, enough people have complained of blown speakers for me to feel it isn't maybe smart to take an average 88db efficient speaker with a 200 watt power handling and feed it 1000 watts RMS. That it might make more sense to get a 95db efficient speaker and feed it 200 watts.

I believe there is a guy on this forum who has repeatedly blown the tweeters on his KEF speakers and I'm sure his amplifiers are nothing crazy.

 

[Tony V.]

I still stand by my view that most people don't have anywhere near enough amplifier power to meet the dynamic peaks of movies or movies without clipping.

The average person I agree but Im willing to bet many that are on forums like this have setups that exceed the "average setup" myself included.

I do agree that receivers without pre-outs (sadly the ones that should have them) are likely under-powered and suffer alot of distortion when driven to even close to reference levels. Even in my own system I use outboard amps to drive my mains (EVsentry 500 studio monitors) but my Onkyo 805 is no slouch either.

By the way this is a great thread, lots of discussion and good info!

 

[Matthew J Poes]

The average person I agree but Im willing to bet many that are on forums like this have setups that exceed the "average setup" myself included.

I do agree that receivers without pre-outs (sadly the ones that should have them) are likely under-powered and suffer alot of distortion when driven to even close to reference levels. Even in my own system I use outboard amps to drive my mains (EVsentry 500 studio monitors) but my Onkyo 805 is no slouch either.

By the way this is a great thread, lots of discussion and good info!

Yes there are a lot of folks on forums that are exceptions to my "average" comment. I'm still shocked at the number of people sticking very large JBL Cinema speakers in their homes! In fact the number of people that even moved up the line to the models designed for large cinemas is even more shocking. They can certainly hit reference levels and then some.

I had damaged some of my amplifiers earlier this year and while I was repairing them used the amplifier built into my receiver to power my center channel. I have 95db at 1 watt efficient speakers and the receiver supposedly puts out something like 130 watts rms. I heard a kind of hardness on voices during loud movie scenes and thought my compression driver was blown. It was reproducible, but only at louder levels. Never crossed my mind that it could possible be amplifier rated, didn't seem possible. A friend of mine who designs speakers for a living said he highly doubted it was a blown compression driver, that in his whole career he had never seen a normal CD blown under these conditions. I took measurements of the speaker with a normal amplifier and it was fine. I hooked it back up and noticed that the distortion was rising in a way that was more consistent with a clipped amplifier. I measured the amplifier with the speaker connected and sure enough the amplifier was clipping.

Now I have personally measured the efficiency of my speakers, My receiver was reviewed and tested to meet its rated specs. That showed me that in practice receivers really can be inadequate. That ~100 watts really probably isn't enough for reference level home cinema unless the speakers are really efficient.

 

[Tony V.]

on the "other" forum I had done alot of digging and found bench tests many receivers that could not even reach 2/3rds of their rated power output driving 5 channels. Many were at around half.

 

[Matthew J Poes]

on the "other" forum I had done alot of digging and found bench tests many receivers that could not even reach 2/3rds of their rated power output driving 5 channels. Many were at around half.

Yeah I think that's common. The All channel's driven test usually shows something like that. It's why I do agree with the OP's desire to use separate amps, but his Krell is better than most at the ACD test.

It's not a receiver problem, its a power supply problem and impacts any amplifier of any design. A number of companies doing full disclosure type ratings of their products note that higher channel amplifiers tend to put out less power as the total number of channels is increased. I've seen a few where its say an 11 channel amplifier driven with some channels partially (say half power) and some channels fully (say 3 front channels) and still show quite a drastic reduction to a single channel or two channels. This stems from the limitations of the wall to supply enough current and the power supply itself.

It's also why I wish we were like Europe and had 220 wall voltage. It wouldn't fix the power supply problem, but our walls would get a big boost in total power output and it would reduce the need for such heavy duty power connections and the higher losses we experience with distance. I even looked into installing a 240 line in my theater, but I ran into some code problems. The electrical is actually run but not hooked up at the moment. Instead I have 3 separate 20 amp lines in the closet and 2 more 20 amp lines for wall outlets and lights. Admittedly more than enough for my needs right now.

 

[Talley]

I still stand by my view that most people don't have anywhere near enough amplifier power to meet the dynamic peaks of movies or movies without clipping.

And me too. Which is why I brought up mono-blocks per channel. Depending on the amplifier of choice this would give enough headroom.

 

[Talley]

My krell drives 110wpc @ 6 channels driven without distortion. But thats all the steam it has. My XPA-7 is rated 200wpc all channels driven and has test data to back it up. Still only does 300w @ 4ohms but all channel driven it meets this goal. Would need to be combined with some 98db effecient speakers too

I just ran -10db on my system with the subs turned off and was hitting peaks around 102 near listening position but the rest of the audio was in the 85-90 range while the quiet scenes were in the 75ish range. This is driving with my krell with 5 speakers going at once.

It's pretty loud and I didn't feel the need to increase the volume.

 

[Talley]

Yeah I think that's common. The All channel's driven test usually shows something like that. It's why I do agree with the OP's desire to use separate amps, but his Krell is better than most at the ACD test.

It's not a receiver problem, its a power supply problem and impacts any amplifier of any design. A number of companies doing full disclosure type ratings of their products note that higher channel amplifiers tend to put out less power as the total number of channels is increased. I've seen a few where its say an 11 channel amplifier driven with some channels partially (say half power) and some channels fully (say 3 front channels) and still show quite a drastic reduction to a single channel or two channels. This stems from the limitations of the wall to supply enough current and the power supply itself.

It's also why I wish we were like Europe and had 220 wall voltage. It wouldn't fix the power supply problem, but our walls would get a big boost in total power output and it would reduce the need for such heavy duty power connections and the higher losses we experience with distance. I even looked into installing a 240 line in my theater, but I ran into some code problems. The electrical is actually run but not hooked up at the moment. Instead I have 3 separate 20 amp lines in the closet and 2 more 20 amp lines for wall outlets and lights. Admittedly more than enough for my needs right now.

After I get the Oppo I can run all my equipment at 240v if I use the Emotiva. Every piece of equipment at 240v and I have large feeders #2awg for the amp and #8awg for the subs/processor EACH having it's own 20a circuit.

I do not experience any power delivery issues at all..... NONE.

 

[Matthew J Poes]

My krell drives 110wpc @ 6 channels driven without distortion. But thats all the steam it has. My XPA-7 is rated 200wpc all channels driven and has test data to back it up. Still only does 300w @ 4ohms but all channel driven it meets this goal. Would need to be combined with some 98db effecient speakers too

I just ran -10db on my system with the subs turned off and was hitting peaks around 102 near listening position but the rest of the audio was in the 85-90 range while the quiet scenes were in the 75ish range. This is driving with my krell with 5 speakers going at once.

It's pretty loud and I didn't feel the need to increase the volume.

That sounds about right. Like I mentioned, there is a difference between technically achieving reference level which is assessed with test tones, and practically meeting it based on how videos are mostly encoded, which makes use of all the speakers anyway. If the engineers really intended peak levels to be like 115db's above 80hz then I think its ok to say that is too loud and dangerous to your hearing. Maybe turning it down isn't such a bad idea.

The Emotiva amp will only give you 3db's more output than the Krell. The Krell is quieter and has somewhat lower distortion, but the emotive amp still has REALLY low distortion and noise and is well designed. The emotive puts out 300 watts into 8 ohms one channel driven and with high pass filters on the surrounds and center and probably a bit less in the signal itself, I suspect that you are getting more than 200 watts from the Emotiva to the mains if you tried that.

What about biamping the mains as a test to see if you like the sound any more? That would allow you to at least hear what doubling the power reserves does to the sound. Just use a Y adapter with the input on the amplifier to mirror the signal.

Your power situation sounds nuts, but as a master electrician I should not be surprised. My theater was built to code and passed all inspections which meant...I had to do a lot of strange things based on village, county, and state code even if it compromised the theater. I was able to get some special permissions, but they were very particular with electrical. I couldn't run a 240 line into a domestic closet. I also had to use the gauge of wire that is code for a 120/20 amp line. I don't recall what that is anymore, but I asked about using thicker wire and was told that if I go thicker than I need to use 30 amp breakers with 30 amp outlets (The wire couldn't exceed the rating of the outlets and breakers), which once again changed things. I also had to pay different rates depending on this, so rather than just paying a standard hourly rate, the electrician was charging extra for anything overly unusual. To make the inspectors happy, save me some money, and give me future upgrade options we ran the 240/30 amp line and installed the double breaker, but its not actually connected in the breaker box or outlet box (and is locked out with a tag from the village). My contractor offered to hook it up for me if I wanted, but I've not bothered for now. As it stands my amplifiers cannot exceed the amperage of my three 20 amp lines that are hooked up. I have my sensitive electronics and receiver on one of the 20 amp lines, the main amplifier and center amplifier on a 20 amp line, and finally the sub amps on the 3rd line.