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A Guide to AVR power in stereo & multi-channel setups

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Posted (edited)

Summary

Read the published power specifications of an AVR carefully. Expect to see at least a power per channel for 2 channels, 20Hz-20 kHz, 0.1-0.2% THD.  The 2 channels power at full frequency range with low THD is a good indicator of stereo power.

 

If the specifications have a multi-channels power per channel, it is likely to deliver in practice.  The Marantz 70% Power Guarantee will give at least 70% of the 2 channels power when used with 5 channels. Many AVRs from other brands can also make the guarantee.

 

In the absence of a multi-channels power number, use the total power consumption (sometimes hidden in manual) as a proxy to compare various AVRs.

 

You can get a low estimate of the multi-channel power by dividing the total power consumption by the number channels @60% efficiency, typical of Class A/B amps.  Entry level AVRs will perform at least to this estimate and higher end AVRs will do much better.

 

When there is no information on 2 channels power in the specifications, your guess is as good as mine as to how well an AVR will perform for stereo and multi-channel.

 

Introduction

A question that regularly comes up is how much power can an AVR deliver in both stereo and multi-channel setups.  It is not helped by AVR vendors delivering misleading numbers in their specifications for marketing purposes and without any information on multi-channel performance.  To understand how and why AVR companies do this, please have a look at this old but still relevant Audioholics article.

 

The guide will answer the following:

  1. What to look for in specifications?
  2. What power can an AVR deliver in a stereo setup?
  3. What power can an AVR deliver in a multi-channel setup?

 

Will use data from existing equipment to illustrate and support the discussion. Most importantly, will be using independent Sound & Vision Test Bench results (which unfortunately ceased since mid 2018).  Please note that I am not technically literate on power amps and welcome input from those who do.

 

What to look for in specifications?

AVR vendors have long focused on maximising the reported power in their specifications for marketing. In the ideal world, the specification will inform the consumer on how well the AVR performs in both a stereo and multi-channel setup.  However, trying to find an ideal using current AVR practice is futile. 

 

Instead, we can use a multi-channel amp to establish the ideal. The challenge is to find a product which has both stereo and multi-channel power numbers.  And it should be using only 1 power supply like an AVR.

 

image.png.0ee8a5d84e5b030b9be113ed6a81890f.png

The Emotiva BASX A700 appears to be credible; the specs have RMS power, the full frequency range and low THD. And it reports both the stereo and  multi-channel numbers.  If only vendors follow Emotiva (who do not make AVRs), we will all be better off.

 

How does a sample of AVRs compare with this ideal?

image.png.b279cca67581b166b3dd188ce064b10f.png

All power in tables are for 8 Ohms.

 

Anthem came closest to the ideal, but they no longer have the multi-channel power number in their current models. The worse was Onkyo, providing data for 6 Ω, 1 kHz, 1% THD, 1 Channel Driven, almost useless. Furthermore,  Onkyo and Yamaha provide a power number with 1 channel driven, 1 kHz, 10% THD.  This is meant to deceive a consumer with a large power number on the specifications.

 

Most specs do not say RMS or continuous power.  As it turns out, they are.  Have assumed that RMS and continuous power are inter changeable when completing the RMS column; technically they are different.

 

You now know what to expect from AVR specifications and know what information to look out for.

 

What power can an AVR deliver in a stereo setup?

Sound & Vision used to independently test the 2, 5 and 7 channels outputs of AVRs (but stopped mid 2018 due to costs and time to run such tests). Let’s compare the published specs with the Test Bench for 2 channels.

image.png.0980c8033eceaa89be78bf59470286b1.png

 

The Anthem MRX-710 and Denon AVR-X4200W fell slightly below the specs.  But the NAD T758V3 was 10W below spec because they used a dubious criterion (8 ohm within rated distortion - what does that mean?) and got shown up by the Test Bench!

 

From the Test Bench, it is easy to conclude that the published 2 channels power per channel at full frequency range with low THD is a good indicator of stereo power.

 

Note that while the AVR can deliver lots of stereo power, it does not mean that they are good for music, due to basic analog stages and using multi-channel DACs. Suggest auditioning an AVR side by side with a stereo setup to see whether the AVR is acceptable for music. If you want best of both worlds, use a stereo setup with HT bypass to drive your shared main speakers.

 

What power can an AVR deliver in a multi-channel setup?

It is frustrating trying to compare the performance of AVRs when there is little, if no information on multi-channels power number. In the absence of this, use the total power consumption (sometimes hidden in manual) as a proxy to compare AVRs.

 

The Sound & Vision Test Bench data provided a valuable insight into how AVRs perform in a multi-channel setup. 

image.png.b0ac848dcd7d637b94b8d2adaada0da4.png

 

The AVRs which published the multi-channel power in their specification passed the tests. Both Arcam AVR-850 and NAD T758V3 beat their specifications.  The Anthem MRX-710 also beat the declared power for 5 channels, even though it had 7 channels; Anthem no longer declare 5 channels power in current models.  My experience with the Anthem MRX-710 and NAD T758V3 suggests that they had enough power, even when pushed hard in a large room.

 

image.png.d064101e65a6976278907d6c46526c16.png

 

Some interesting observations:

  • SR 7011 easily beat the Marantz 70% Power Guarantee (for 5 channels) with 84%.  Marantz is using something other than Class A/B amps to achieve this. A short discussion of the guarantee is here,  As it turns out, many AVRs can easily make the guarantee.
  • Arcam’s AVR-850 2 channels Test Bench is slightly larger than the  5 and 7 channels power; indicates that it is a modular design.
  • For the Anthem, NAD, Denon and Marantz, 7 channels power is 75% of the 5 channels number.  at least 60% of the 2 channels spec.
  • Of more concern are the Yamahas dropping by 50 to 60% when increasing from 5 to 7 channels producing about 30% of the 2 channels spec when driving 7 channels.  Maybe it is better   Recommend selecting a Yamaha model with the higher 2 channels power, even if it means paying a little more.

 

What puzzles me is why vendors like Marantz, Denon and Anthem do not want to publish their 7 channels number?  Their numbers beat the NAD T758V3 in the 7 channels Test Bench and are good enough to drive many speakers.  

 

In the absence of a published multi-channel power number, can it be estimated? 

 

It may be possible to derive the multi-channel power by dividing the total power consumption by the total number channels @60% efficiency, typical of Class A/B amps.  Audioholics rates Class A/B amps as between 50 to 70% efficient. Let's test that for the Denon and Yamaha AVRs:

image.png.1f5ea6e3b10d720187d1bfb120bca9b8.png

 

The estimate is lower than Test Bench data and provides a floor for determining whether it can power surround speakers.  Entry level AVRs will perform at least to this estimate and higher end AVRs will do much better.

 

Coming up with anything meaningful is difficult with the Onkyo specification of 200 W/Ch 6 Ω, 1 kHz, 1% THD, 1 Channel Driven.  As Audioholics puts it, it is like trying to determine the maximum speed of your car on level ground when all you have is its speed going downhill assisted by a strong tail wind.  Your guess is as good as mine. 

 

Thank you for taking the time to read this.  It has been an interesting exercise where I made a number of wrong turns to arrive at this guide. It has changed my view of AVR power.

 

Hope this helps you to select an AVR which will give you lots of enjoyment.

 

Edited by Snoopy8
Fixed pictures, typos, minor edits, added power guarantee info

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So as it turns out, the specs from my Yamaha RX-V3073 aren’t that shabby for a 2 channel setup. (As you stated, it doesn’t overcome the music limitations with avrs.)

 

Rated Output Power (2-channel driven)
(20Hz to 20kHz, 0.06% THD, 8Ω)
Front L/R 150 W + 150 W

 

https://au.yamaha.com/files/download/other_assets/3/328083/RX-V3073_V2073_om_En.pdf

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13 hours ago, Snoopy8 said:

SR 7011 easily beat the Marantz 70% Power Guarantee (for 5 channels) with 84%.  Marantz is using something other than Class A/B amps to achieve this. A short discussion of the guarantee is here,

You have done a great job with the thread @Snoopy8.

 

I will focus on the Marantz figures ;) It is easier to focus on 1 manufacturer for me.

SR7011:

  • 710W power supply
  • 125W per channel stereo claim
  • 70% guarantee for 5 channels
  • Testbench performance is in the table below
13 hours ago, Snoopy8 said:

The Sound & Vision Test Bench data provided a valuable insight into how AVRs perform in a multi-channel setup. 

image.png.b0ac848dcd7d637b94b8d2adaada0da4.png

 

Lets look at the power claims like this: Power Supply Rating - Amplifier Channels' usage - Remaining AVR circuitry and spare room (X) = Y

 

Specifications:

Stereo mode:

710 - 125*2 - X = 460 - X (plausible)

5 channel mode with 70% guarantee:

710 - (125*5*.7) - X = 437.5 - X (plausible)

7 channel mode:

There is no guarantee and there are no other claims

 

Bench performance:

Stereo mode:

710 - 138.7*2 - X = 432.6 - X

5 channel mode with 70% guarantee:

710 - 104.9*5 - X = 185.5 - X

7 channel mode:

710 - 75.1*7 - X = 184.3 - X

 

Marantz made a claim that each channel in a 5 channel output configuration will have a rating of at least 70% of the 2 channel output configuration. Does that mean that in a 5 channel output configuration the benchmark should never be more than 125*0.7=87.5W? Does the 104.9W measured mean that they are not using A/B class? Not necessarily.

 

I could try and reverse logic some of the specifications:

75.1/0.75 (75.1W output with a highly efficient A/B class stage) =~ 100.133W

~100.133W*7 = ~ 701W

710 - 701 - X = 9 - X

That seems highly unlikely! Does this suggest that they are using D class? Maybe or maybe not.

I think the last piece of the puzzle is the power supply and the X factor. How honest are they in the 710W power usage? Is that the figure for 2, 5 or 7 channel output? How much power is needed to run the rest of the circuitry (other than amplification channels)? Maybe 9W is enough.

 

I think the only way to know more is to have Marantz's design and/or take more measurements.

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13 hours ago, Snoopy8 said:

Most specs do not say RMS or continuous power.  As it turns out, they are.  Have assumed that RMS and continuous power are inter changeable when completing the RMS column; technically they are different.

RMS vs continuous?

https://en.wikipedia.org/wiki/Audio_power#Continuous_power_and_"RMS_power"

https://en.wikipedia.org/wiki/Root_mean_square#In_common_waveforms

 

RMS is a calculation that is useful in theory and design and its really about a clearly defined waveform. Continuous sine wave output as measured in audio products has a THD component. Manufacturers can claim higher RMS with higher THD. As I understand it the standard for measuring audio output power makes the RMS and continuous terms interchangeable; I would think this is because they are close enough. I would need to look at the standard itself, not just wikipedia. Getting theoretical RMS out of a manufacturer would be fairly pointless, and it would be a waste of their time. If the standard was to be updated to use 'continuous sine wave output' terminology then it would be more accurate. I would read either terminology in the specifications to mean 'continuous sine wave output'.

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Posted (edited)

To add another comment.

 

@Snoopy8 I agree with you; don't believe the hype in the marketing, especially when there are a bunch of omissions. It's been good to think about this.

 

In case of that Marantz it seems that it measures in line with the marketing. But, until I see an official Marantz confirmation (via an official statement or schematics or something else concrete) I won't be completely satisfied that it's A/B class.

 

So what does one base their buying decision on? Listening to the AVR in their own room/setup with their own speakers. As a bonus do it with and without a separate power amplifier. I don't think that will be possible for most people, unfortunately. It would be good to have more completeness and transparency in published information.

Edited by gwurb

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9 hours ago, gwurb said:

You have done a great job with the thread @Snoopy8.

 

I will focus on the Marantz figures ;) It is easier to focus on 1 manufacturer for me.

SR7011:

  • 710W power supply
  • 125W per channel stereo claim
  • 70% guarantee for 5 channels
  • Testbench performance is in the table below

Lets look at the power claims like this: Power Supply Rating - Amplifier Channels' usage - Remaining AVR circuitry and spare room (X) = Y

 

Specifications:

Stereo mode:

710 - 125*2 - X = 460 - X (plausible)

5 channel mode with 70% guarantee:

710 - (125*5*.7) - X = 437.5 - X (plausible)

7 channel mode:

There is no guarantee and there are no other claims

 

Bench performance:

Stereo mode:

710 - 138.7*2 - X = 432.6 - X

5 channel mode with 70% guarantee:

710 - 104.9*5 - X = 185.5 - X

7 channel mode:

710 - 75.1*7 - X = 184.3 - X

 

Marantz made a claim that each channel in a 5 channel output configuration will have a rating of at least 70% of the 2 channel output configuration. Does that mean that in a 5 channel output configuration the benchmark should never be more than 125*0.7=87.5W? Does the 104.9W measured mean that they are not using A/B class? Not necessarily.

 

I could try and reverse logic some of the specifications:

75.1/0.75 (75.1W output with a highly efficient A/B class stage) =~ 100.133W

~100.133W*7 = ~ 701W

710 - 701 - X = 9 - X

That seems highly unlikely! Does this suggest that they are using D class? Maybe or maybe not.

I think the last piece of the puzzle is the power supply and the X factor. How honest are they in the 710W power usage? Is that the figure for 2, 5 or 7 channel output? How much power is needed to run the rest of the circuitry (other than amplification channels)? Maybe 9W is enough.

 

I think the only way to know more is to have Marantz's design and/or take more measurements.

Thank you for trying to figure this out.  Let me add some fuel to the fire from Audioholics review of SR8012 done last year.  (pity it was not SR7011). I have done a screenshot of their measurements

image.png.3db75d41d3d9e50a4a28411e21eeb93b.png

 

image.png.32287fcb129ce4853fb4e1254636c4d3.png

 

 

6 hours ago, gwurb said:

In case of that Marantz it seems that it measures in line with the marketing. But, until I see an official Marantz confirmation (via an official statement or schematics or something else concrete) I won't be completely satisfied that it's A/B class.

Audioholics says Marantz is Class A/B!

 

image.png.80ab84b1037e268b5edad5ca3e970ae2.png

 

From the specs, total power consumption of 780W. Using Marantz own numbers, this would give a power efficiency of 695.8/780 = 89% !!!   

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I have always said its class AB. pity we dont just listen to 1khz sweeps :D what did  I say about how testers use their opinions on what to test... i personally woudl rather see a 20-20hz test...

 

and yes as per my previous note ... it will most definitely run very hot... totally inadequate heat sinking as is often the case in aVRs..

 

refer the likes of cambridge audio and harman kardon that  did massive heatsink, forced air ventilation tunnels through their AVRS... and with still modest claims... a pity they are no longer but no wonder with this over enthusiastic marketing specs makers like above use...

 

and NO a class AB amp is not in any reality going to have 89% efficiency ... tell me this isnt a case of massive porkies !!!

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1 minute ago, betty boop said:

and NO a class AB amp is not in any reality going to have 89% efficiency ... tell me this isnt a case of massive porkies !!!

I hear you!  Have Marantz found a way to fudge the tests?   To me, it is a risky strategy which can damage a brand who has audiophile roots.  

 

All this does not make sense. Are you on Audioholics?  If so, ask the author how it is possible to get 89% efficiency on Class A/B amps?

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13 minutes ago, Snoopy8 said:

I hear you!  Have Marantz found a way to fudge the tests?   To me, it is a risky strategy which can damage a brand who has audiophile roots. 

found a way ? they've been fudging it all along with other AVR brands Denon, yamaha, onkyo, pioneer and sony for years ? 

 

will find as go up and pay more they deliver more power but fudge remains.

 

if you want fudge go look at their KI ruby integrated ... fudge to the core... I say this as a ki ruby disc player owner and the player is absolute gem truly but i wouldnt touch the integrated ! 

 

since heres an amp with 130W consumption... it has a small torroid inside...

 

from the spec sheet...

􏰤Pow􏰄er Output 􏰢􏰆􏰁􏰃􏰆􏰁􏰊 100Wpc @ 8 Ohms,
200Wpc @ 4 Ohms

 

so how they manage 100 wpc ? let alone 200Wpc hey ? from a 130W consumption ? :D

 

as to why is it possible ...

it is because along with publications  ... they are part of the problem to keep perpetuating this ... it drives sales, marketing why blow the cover... keep the tills ticking over it pays their bills....

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heres 2ch amp thats 100wpc the arcam fmj a22... power consumption 800W ! :) 

 

 

Qybo3BTTk9fncnOmSZB0V8BoeFEuN_NHwBp2Y6w4

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@betty boop others provided misleading numbers but Marantz did the 70% power guarantee. Why did they stick the neck out?

 

It is easy to go on about how bad AVR companies are. But we have independent data from both Audioholics and Sound & Vision which suggests that there is something to the 70% guarantee.

 

And is Audioholics part of the conspiracy?

https://www.audioholics.com/audio-amplifier/sound-united-receiver-power-ratings

 

This is not like you.  Where is the inquiring you? 

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19 minutes ago, Snoopy8 said:

others provided misleading numbers but Marantz did the 70% power guarantee. Why did they stick the neck out?

I’ve studied marketing I understand how differentiation works :)
 

Fortunately some things easily seen through :) why is marantz have guarantee when almost identical specd denon cousin doesnt ... neither pioneer or Onkyo fell in the same companies grips so would expect them to be different ...

19 minutes ago, Snoopy8 said:

is easy to go on about how bad AVR companies are. But we have independent data from both Audioholics and Sound & Vision which suggests that there is something to the 70% guarantee.

Independent data which suits their opinions...

19 minutes ago, Snoopy8 said:

inquiring you? 

Not much to inquire when some simple facts tell all ... :) 

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9 minutes ago, betty boop said:

I’ve studied marketing I understand how differentiation works :)
 

Fortunately some things easily seen through :) why is marantz have guarantee when almost identical specd denon cousin doesnt ... neither pioneer or Onkyo fell in the same companies grips so would expect them to be different ...

Independent data which suits their opinions...

Not much to inquire when some simple facts tell all ... :) 

I am disappointed you did not even read the Audioholics link. It is so easy to go conspiracy and dismiss things. There is nothing I can add because you have made up your mind. 

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4 minutes ago, Snoopy8 said:

I am disappointed you did not even read the Audioholics link. It is so easy to go conspiracy and dismiss things. There is nothing I can add because you have made up your mind. 

I have actually read the link and not just once ..  . There is no conspiracy that I see.  it’s just marketing nothing more. Labelling doesn’t change Underlying facts.
 

I’ll leave there and this thread and all other threads been created on topic as quite clearly taking personally. 

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May I ask can I draw a conclusion from the discussion above and disregarding the cost of the AVR's all of them would be capable of driving a vast array of speakers in stereo mode to moderate (?) volume levels well within their capacity?

 

Even the moderately priced Yamaha model? One thing I have found attractive about AVR's in the past was their connectivity options although these days in the digital realm stereo integrates are offering many more connectivity options.

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16 minutes ago, allthumbs said:

May I ask can I draw a conclusion from the discussion above and disregarding the cost of the AVR's all of them would be capable of driving a vast array of speakers in stereo mode to moderate (?) volume levels well within their capacity?

 

Even the moderately priced Yamaha model? One thing I have found attractive about AVR's in the past was their connectivity options although these days in the digital realm stereo integrates are offering many more connectivity options.

no problem..... yes still get what pay for and show usual care with partnering as do with stereo amps. and yes its quite likely you will get a better featured and sound quality unit if looking at dedicated 2ch... as its not trying to be a multichannel thing with all its features and just focussing its goodness on 2ch :) 

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Posted (edited)

I'm still completely convinced that most people would be better off for sound quality by not buying an AVR and instead spending $2k to buy an old Oppo Bluray player as a multi channel source and plugging it into a stack of second hand matched stereo amps.

 

Even my 2008 Panasonic flag ship Bluray player still had better  quality multichannel preout stage than $2.5k Yamaha AVRs 10 years later. 

 

The right Oppo still has ARC and another HDMI input or two, can take USB hard drives and also has SPDIF out to feed a higher end DAC if you're not into the many great aftermarket Oppo mods.

 

Only thing is ATMOS something you must have as this is newer than where Oppo signed off? Although I suspect the HDMI Audio out on the Oppo would permit a sound bar processor hack outputting to something appropriate to get this running. 

 

Went through the AVR cycle a few years ago. Auditioned more and ditched them altogether. 

 

I also feel they are becoming more redundant with streaming. Especially the whole multi zone thing which saw me running many metres of cable through the house with gyprock off. 

 

Now running multiple stereo amps and two systems. Have a 205 and 105 for upstairs and downstairs. 

Edited by DrSK

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Posted (edited)
On 19/03/2020 at 10:59 AM, allthumbs said:

May I ask can I draw a conclusion from the discussion above and disregarding the cost of the AVR's all of them would be capable of driving a vast array of speakers in stereo mode to moderate (?) volume levels well within their capacity?

 

Even the moderately priced Yamaha model? One thing I have found attractive about AVR's in the past was their connectivity options although these days in the digital realm stereo integrates are offering many more connectivity options.

In my experience you can get better stereo quality out of the right old $100 Gumtree amp than a $2.5k AVR.

 

And for $1000-$2000 there are great old amps out there that still hold their own that cost as much as a Holden Commodore new in their day. Some of these can dump enough current into your mains they'd melt your AVR into a lump of metal. 

 

If you want connectivity you can get a great DAC to feed it from Giesler Audio plugged to a laptop, network streamer or optical from a TV. 

 

And from my experience many AVRs simply can't dump current and lose the low end dynamics, seem to be reliant on external self powered subs. This significantly impacts stereo on full range mains. 

Edited by DrSK

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17 minutes ago, DrSK said:

Only thing is ATMOS something you must have as this is newer than where Oppo signed off? Although I suspect the HDMI Audio out on the Oppo would permit a sound bar processor hack outputting to something appropriate to get this running. 

There is also a question of room correction. 
 

So Oppo with attached storage, attached Chromecast/appleTV/etc, attached audio streamer -> some room correction DSP -> amp -> speakers.

 

That would also leave out Atmos or anything else that gets added after Oppo latest release.

 

If the amp part of the AVR doesn't suit one's taste then it's possible to buy a processor with all the features and add on an amp. Or just use the pre part of the AVR.

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Posted (edited)
2 hours ago, gwurb said:

There is also a question of room correction. 

For sub maybe.

 

Oppo does trim and delay, so some basics. 

Quote

 

So Oppo with attached storage, attached Chromecast/appleTV/etc, attached audio streamer -> some room correction DSP -> amp -> speakers.

Yep 

Quote

 

That would also leave out Atmos or anything else that gets added after Oppo latest release.

 

If the amp part of the AVR doesn't suit one's taste then it's possible to buy a processor with all the features and add on an amp. Or just use the pre part of the AVR.

Although the pre out on Yamaha from my experience are equally trash compared to a decent Bluray player.

 

Room correction can be of benefit for sub range. Anything else I'm of the opinion better to fix the room and placement of speakers and listening position. Most room 'correction' I've heard seems to be at the expense of time domain creating frequency dependent pockets of spectral mud in my opinion. 

Edited by DrSK

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