So how does it sound without the Power Amp ?

[Jester1066]

I only need one

I'm undecided on number, brand etc
Actually this thread was supposed to help with that ...

My long game is to go full pre/pro though.

 

[DodgeTheViper]

I need one for the moment then it’ll be another one/two. But I’m getting this one sorted first.

 

[sebna]

I've recently become without a Power Amp and just have the AVR powering my speakers. While I'm here I thought I'd carry out a little listening test of just using the AVR against the AVR with additional power. The Receiver is a Marantz SR8012 and the Power Amp was a Emotiva XPA.

Once the power Amp was removed I didn't rerun the EQ but did check all the channel levels along with the Subs, just for good measure. The speaker config. wasn't changed and remained as 5.2.4. So just really simple, nothing technical, no measurements, no graphs, just me having a good old demo session. For this one, it's a movie session only, no music.

Up for listening and in no particular order is, Alita: Battle Angel, John Wick 2, Edge Of Tomorrow, Oblivion & Ready Player One. I chose two listening volumes, the first one at -15.0db and the second at -5.0db. I know even -15.0db could be considered loud or even too loud for a lot of people and -5.0db being totally out of the question. But they represent where I do my listening, typically around -10.0db give or take a few.

First up, Oblivion at -15.0db. At this volume level I didn't expect to encounter any particular issues, and I didn't. I don't consider it to be a particularly complex or dynamic track though.
At -5.0db. Even at this level it didn't sound like things were falling apart. It sounded reasonably controlled if slightly livelier which felt like it was presenting more detail. The AVR didn't sound like it was struggling, but it did have a slight edge to it though.

Next up, Alita: Battle Angel at -15.0db. Again at this volume there was no real problem. Plenty of detail and I could watch the complete movie at this level.
At -5.0db. Now this sounded completely nuts at this volume. The sound became harsh and harder on the ears, and it was more difficult to pick out detail amongst the action. No way could I watch the movie at this volume, it was far too bright and edgy.

Next, Ready Player One at -15.0db. I chose the race scene here, you know the one. This was another one that was still presenting the detail but had a slight edge that I'd heard previously. Like it's bordering on being too loud and marginally too uncomfortable for a whole movie.
At -5.0db. Oh my days, turn it down ! Similar to before, the detail becomes lost in the mayhem and it just gets very rowdy and unsustainable for even a short period of time, never mind the whole movie.

Next, John Wick 2 at -15.0db. You got to love those handgun shots. They come across with such frightening force that they almost hurt the viewer. The impact is astonishing and I think this would be plenty loud enough with the AVR on it's own.
At -5.0db. If you don't want a sore head, don't listen to this at -5.0db as those handgun shots will rip clean through your skull. The shotguns are crazy enough but the handguns are so intense that you could quite likely raise a couple of inches out of the seat, as I did. The scene was in the night club and JW is on the stage and he fires a shot before jumping off and venturing into the caverns. It's head splitting and totally uncomfortable but quite an experience. I warn you not do it !

Next, Ready Player One at -15.0db. OK, I didn't get to attempt this one after my experience with JW 2, I needed time to recover my senses. My head was still a little shell shocked, quite literally. But I dont think I would have experienced anything differently to what I'd heard previously, so it's probably not that much of a loss.

So after all that, I think around -15.0 db is probably the limit. And even then it really depends on what you are listening to and the quality of the mix etc. Jumping the volume from there and I know -5.0 is crazy loud but things to start to break up. It just sounds really loud, losing detail and control with the dynamics running wild and edgy. A bit like an Orchestra without their Conductor. With the Power Amp in play I didn't experience any of these things. I could raise the volume to -5.0db and still pick out detail without the edgy harshness. The sound remained a lot smoother and more sustainable over a period of time.

I haven't replaced the Power Amp yet and so could do another set of demo's now that i've recovered

Love the humor part of of it and I fully agree in what the dedicated PAs bring to the mix but they also can bring more than what described. Still what described is the key things anyway from listening levels perspective (so probably what is the most important factor for in HT in relation to PA).

 

[Harkon321]

I'm currently running 7.1.4 from my Denon 4400, with a smaller 2 ch amp for two surrounds.

Room is fairly small (about 3.5m wide by 3.8m long).

I listen about -10db for films, but above that it can sound quite harsh and overly bright. Speakers, with exception of a pair of monitor audio inwall surrounds, are all M&K - fronts are M&K IW150. My gut is that a power amp, even for the LCR would help this, although I don't have a huge amount of absorption, so that is another one to look at.

 

[sebna]

I'm currently running 7.1.4 from my Denon 4400, with a smaller 2 ch amp for two surrounds.

Room is fairly small (about 3.5m wide by 3.8m long).

I listen about -10db for films, but above that it can sound quite harsh and overly bright. Speakers, with exception of a pair of monitor audio inwall surrounds, are all M&K - fronts are M&K IW150. My gut is that a power amp, even for the LCR would help this, although I don't have a huge amount of absorption, so that is another one to look at.

It should help in at least two ways. 1) It will provide quality power for the hardest working 3 in front and 2) it will free up AVR's PSU capacity to do a better job powering remaining speakers. So potentially not only your LCR will gain but also the remaining ones.

 

[Deleted member 901590]

I'm currently running 7.1.4 from my Denon 4400, with a smaller 2 ch amp for two surrounds.

Room is fairly small (about 3.5m wide by 3.8m long).

I listen about -10db for films, but above that it can sound quite harsh and overly bright. Speakers, with exception of a pair of monitor audio inwall surrounds, are all M&K - fronts are M&K IW150. My gut is that a power amp, even for the LCR would help this, although I don't have a huge amount of absorption, so that is another one to look at.

Are you using Audyssey reference or flat curves?

Have you tried using the Cinema EQ function? "Gently softens the upper treble range of movie soundtracks to reduce possible harshness and improve clarity".

 

[rccarguy2]

I'm currently running 7.1.4 from my Denon 4400, with a smaller 2 ch amp for two surrounds.

Room is fairly small (about 3.5m wide by 3.8m long).

I listen about -10db for films, but above that it can sound quite harsh and overly bright. Speakers, with exception of a pair of monitor audio inwall surrounds, are all M&K - fronts are M&K IW150. My gut is that a power amp, even for the LCR would help this, although I don't have a huge amount of absorption, so that is another one to look at.

Try borrowing a good 7ch amp put all base channels on that.

Something like emotiva xpa/iota/tonewinner. Or on lower budget bas X. But personally I'd save up the bigger amp

 

[Harkon321]

Used Audyssey and then tweaked it under the guidance of @mb3195 to reduce the top end. It's definitely better but I think running 9 channels from the Denon at full tilt is just asking too much. It would be inline with what @DodgeTheViper has posted above.

 

[rccarguy2]

Used Audyssey and then tweaked it under the guidance of @mb3195 to reduce the top end. It's definitely better but I think running 9 channels from the Denon at full tilt is just asking too much. It would be inline with what @DodgeTheViper has posted above.

For the price pretty good unless you look at big brands anthem ati parasound rotel etc

IOTAVX AVXP1

The IOTAVX AVXP1 is a High Quality, High Power, Multi-Channel Power Amplifier that offers 7 channels of class AB amplification with enough real world power

www.iotaenterprises.co.uk

 

[DodgeTheViper]

Used Audyssey and then tweaked it under the guidance of @mb3195 to reduce the top end. It's definitely better but I think running 9 channels from the Denon at full tilt is just asking too much. It would be inline with what @DodgeTheViper has posted above.

It was an extreme test tbf. I’m glad I’ll have an amp back in this week though.

 

[Mr Wolf]

I listen about -10db for films, but above that it can sound quite harsh and overly bright. Speakers, with exception of a pair of monitor audio inwall surrounds, are all M&K - fronts are M&K IW150. My gut is that a power amp, even for the LCR would help this, although I don't have a huge amount of absorption, so that is another one to look at.

Based on what I've read, if the room is untreated I suspect this harshness will have a lot to do with the increased reverberation/decay time you will get at higher listening levels. I've haven't done it yet myself but I think you can use REW to measure the RT60 (i.e. time to decay to 60dB) across the frequency range which can help identify this issue and point you towards the right acoustic treatment.

Re. the power situation, the IW150s have 90dB sensitivity so at -10dB volume in a room that size they should only be pulling a few watts each on the loudest 20dB peaks. A tell-tale sign of high in-room speaker efficiency at the MLP would be if you have to use very negative speaker trim levels (say -12dB to -8dB) in the AVR in order to calibrate 0dB volume to output 75dB on the internal test tones. If want to actually know your power need, a True RMS voltmeter (cost £35) can be used to measure the maximum possible peak voltage/power draw of each speaker channel. I did this recently and it confirmed that I need slightly less power than I originally thought, a max. of 5W per channel at 4-Ohms at -10dB volume on my centre channel.

 

[logiclee]

I'm currently running 7.1.4 from my Denon 4400, with a smaller 2 ch amp for two surrounds.

Room is fairly small (about 3.5m wide by 3.8m long).

I listen about -10db for films, but above that it can sound quite harsh and overly bright. Speakers, with exception of a pair of monitor audio inwall surrounds, are all M&K - fronts are M&K IW150. My gut is that a power amp, even for the LCR would help this, although I don't have a huge amount of absorption, so that is another one to look at.

I have the same Receiver powering 9 channels, slightly larger room and had exactly the same issue although with B&W's. To be fair sounded harsh before -10db.

Front LCR now powered with Emotiva BasX A3.

Today ran Atmos Demo Amaze and Leaf for the Father in Law at -5db. No signs of harshness and no brittle sounding treble.

 

[rccarguy2]

One option would be to get bas X for all side/surround/height channels, let avr power LCR. In the short term use it for LCR a month or so get used to improvement. Then use for side/rears/heights.

Then later on get good amp for LCR.say xpa 3 or ATI 6003 heh

Unusual method but one option

 

[Mr Wolf]

I have the same Receiver powering 9 channels, slightly larger room and had exactly the same issue although with B&W's. To be fair sounded harsh before -10db.

Front LCR now powered with Emotiva BasX A3.

Today ran Atmos Demo Amaze and Leaf for the Father in Law at -5db. No signs of harshness and no brittle sounding treble.

There’s an important difference here though. Your B&W HTM62 centre has 85dB sensitivity so requires about 3.2x the amount of power that Harkon’s 90dB centre does to do the same thing. If an AVR’s baulking at outputting up to 4 or 5 watts per channel then there’s probably something wrong with it.

 

[logiclee]

Then later on get good amp for LCR.say xpa 3

How many living room systems require 300W RMS per channel?

If we consider 9 channels being driven on a X4*** series can have per channel output dropping into the 60's with constrained dynamics (7 channels driven measured at 76W)
The the BasX A3 at 140W all channels driven is a significant upgrade on the Denon's internal amps.

 

[Harkon321]

Re. the power situation, the IW150s have 90dB sensitivity so at -10dB volume in a room that size they should only be pulling a few watts each on the loudest 20dB peaks. A tell-tale sign of high in-room speaker efficiency at the MLP would be if you have to use very negative speaker trim levels (say -12dB to -8dB) in the AVR in order to calibrate 0dB volume to output 75dB on the internal test tones.

Surely the size of the room shouldn’t affect the power needed to reach -10db? Probably showing my ignorance here…

So, are you saying that I shouldn’t need a power amp and that the Denon should be able to drive these to higher levels without issue?

 

[sebna]

Surely the size of the room shouldn’t affect the power needed to reach -10db? Probably showing my ignorance here…

So, are you saying that I shouldn’t need a power amp and that the Denon should be able to drive these to higher levels without issue?

I guess the room size can dictate the distance of MLP to speakers and in that way influence the power requirements.

 

[kenshingintoki]

Surely the size of the room shouldn’t affect the power needed to reach -10db? Probably showing my ignorance here…

So, are you saying that I shouldn’t need a power amp and that the Denon should be able to drive these to higher levels without issue?

It should. Bigger room = bigger space between speakers and listener normally.

Denon can drive speakers loud but I think the issue is distortion.

Power amp = cleaner output = less distortion = more detail IMO.

I'm not sure when diminishing returns kicks in but I'd love to do an A/B test of a £5000 power amp vs a £350 one and see the results with the same processor and speakers.

 

[Mr Wolf]

How many living room systems require 300W RMS per channel?

If we consider 9 channels being driven on a X4*** series can have per channel output dropping into the 60's with constrained dynamics (7 channels driven measured at 76W)
The the BasX A3 at 140W all channels driven is a significant upgrade on the Denon's internal amps.

No more than the equivalent of four channels are FULLY driven at any point by a movie soundtrack. THX don’t even stress test more than 5 channels in their amplifier certification process for this reason. 5 channels driven on X4xxx series is 88W. 140W gives 2dB more output than this, that's all.

Surely the size of the room shouldn’t affect the power needed to reach -10db? Probably showing my ignorance here…

So, are you saying that I shouldn’t need a power amp and that the Denon should be able to drive these to higher levels without issue?

Room size affects it due to extra distance to listener plus the amount of boundary gain you get. In an untreated <3,000Ft3 room boundary gain can add 6dB to the output as we hear twice the amount of sound from reflections than we do directly from the speaker.

Yes, I would be very surprised if your Denon struggled at -10dB with 90dB speakers. With those speakers you should need less than [email protected] to hit reference and -10dB requires only 10% of that level i.e. maximum possible [email protected] or 20W @4-Ohms. And that is on the loudest transient peaks.

 

[rccarguy2]

How many living room systems require 300W RMS per channel?

If we consider 9 channels being driven on a X4*** series can have per channel output dropping into the 60's with constrained dynamics (7 channels driven measured at 76W)
The the BasX A3 at 140W all channels driven is a significant upgrade on the Denon's internal amps.

Xpa 3 for front three
Then bas-x or Nord 125w X 8

Yes the bas X is upgrade on a avr, but amps like ATO 1803 are upgrade over bas X. Two big power supplies, and 18,000uf per channel dedicated storage.

Or get three monoblocs in my avatar for even bigger upgrade

 

[logiclee]

Xpa 3 for front three
Then bas-x or Nord 125w X 8

Yes the bas X is upgrade on a avr, but amps like ATO 1803 are upgrade over bas X. Two big power supplies, and 18,000uf per channel dedicated storage.

Or get three monoblocs in my avatar for even bigger upgrade

In a USA basement Home Cinema build perhaps.

In a UK 6m x 4m living room why spend the extra if there's absolutely no need for the extra power in the system?
As Mr Wolf kindly explains.

 

[logiclee]

5 channels driven on X4xxx series is 88W. 140W gives 2dB more output than this, that's all.

Are we perhaps looking at more than just watts?

How do we measure the ability of a Receiver to deliver dynamics with the relatively small power supply and the usual absence of significant capacitor capacity?

 

[rccarguy2]

In a USA basement Home Cinema build perhaps.

In a UK 5m x 3m living room why spend the extra if there's absolutely no need for the extra power in the system?
As Mr Wolf kindly explains.

It's about budget I already had decent 100w stereo amps pretty much all round, something like eight boxes, wanted to decrease number of boxes, no point downgrading to budget multi channel,.so big upgrade was done to multi channel higher quality.

Bas X is ok but that would have been downgrade

 

[rccarguy2]

Are we perhaps looking at more than just watts?

How do we measure the ability of a Receiver to deliver dynamics with the relatively small power supply and the usual absence of significant capacitor capacity?

Better quality amps will have bigger psu and more capitance The top of the range ATI 6007 has dual 2kw PSU and 60,000uf storage. It'll probably be stable at 0.5ohm

Compared to avr may just have 10,000uf for all 11 channels and 500w PSU

 

[Mr Wolf]

Are we perhaps looking at more than just watts?

How do we measure the ability of a Receiver to deliver dynamics with the relatively small power supply and the usual absence of significant capacitor capacity?

It's a very good point and the answer to this explains why a 30W/channel stereo audiophile amp can sound so much better than a 150W/channel flagship AVR or a 300W HT power amp when playing music.

My understanding is that it's to do with how an amp has been designed to deliver sufficient current in the face of difficult loads (i.e. high phase angles) so things like PSU, capacitance, output devices, transistors, rectifiers etc. all matter. Some AVRs will be designed much better in this area than others, even though they may have similar wattages. It's why an X8500 can sound much better than some of the lesser D&M models.

So the less great an amp is at handling difficult loads the more it makes sense to use it with easy to drive speakers. In my book, that's >89dB sensitivity for LCRs, 8-ohm nominal rated and no impedance dips under 4-Ohms in the critical 80Hz-400Hz region that has the loudest and longest peaks above the crossover point.