Separate power amp needed with 5.2.4 setup?

[Paul DS]

We have been over this ground many times before. Subs DO NOT off load receivers. There is little power below 80 Hz and it falls of rapidly below that point. In addition the sub band is where the tuning peaks of impedance are for most speakers, which means that is just the region as a rule where the demand for current is not as great.

It seems like there is a lot of power in the sub range, but that is only because subs are extremely inefficient converters of electric energy to sound energy, especially sealed ones.

If you have highly efficient LF reproducers like my TLs that sub range consumes very little power. Its all about the "iron man's" law of Hoffman. That says power demands will increase as you lower enclosure size, in that low range, however you do it.

A subwoofer takes off the low end load of a receiver or amplifier. Please explain how this isn't making the load on a receiver or amp much lighter. It's the low heavy frequencies that require power, not treble. If you are using a cutoff frequency of 100 hz, that would be taking quite a load of of any amp/receiver.

 

[PENG]

We have been over this ground many times before. Subs DO NOT off load receivers. There is little power below 80 Hz and it falls of rapidly below that point. In addition the sub band is where the tuning peaks of impedance are for most speakers, which means that is just the region as a rule where the demand for current is not as great.

It seems like there is a lot of power in the sub range, but that is only because subs are extremely inefficient converters of electric energy to sound energy, especially sealed ones.

If you have highly efficient LF reproducers like my TLs that sub range consumes very little power. Its all about the "iron man's" law of Hoffman. That says power demands will increase as you lower enclosure size, in that low range, however you do it.

You've made a general statement that is not true and won't admit it.

 

[IMWhizzle]

Well, I’ve connected the Rotel RMB-1575 today and calibrated the system again with Audyssey.

As expected there is no sound difference whatsoever (that was not my goal) but the distortion is gone. That’s a relief.

Funny thing though, Audyssey set all my speakers 2db louder except for the Atmos speakers (closer to 0.0db in the AVR). I think the gain in the amp is lower than the Marantz.

I don’t have regrets buying this amp. It’s a great feeling having tons of headroom in my system now which is now distortion free. Later this week I’ll watch a couple of movies and listen to my multichannel SACD’s.

 

[IMWhizzle]

I’ve listened to a couple of SACD’s and watched movies at reference level and below. The sound is so much better at louder volumes than before. Almost the same on lower volume levels though. But wow, never knew what I was missing. Pairing a multichannel power amp with this setup is amazing. Especially in movies the dynamic range is awesome. Even my wife smiled during some scenes.

The only bad thing about the amp is it’s color. Only silver was available and it was the last one in my country.

 

[TLS Guy]

I’ve listened to a couple of SACD’s and watched movies at reference level and below. The sound is so much better at louder volumes than before. Almost the same on lower volume levels though. But wow, never knew what I was missing. Pairing a multichannel power amp with this setup is amazing. Especially in movies the dynamic range is awesome. Even my wife smiled during some scenes.

The only bad thing about the amp is it’s color. Only silver was available and it was the last one in my country.

I have no doubt it does sound a lot better at power. I just did an install with a midrange Marantz receiver driving an Elac set up. Only any good if you kept the volume down. Receiver specs are just fraudulent in the power department.

 

[PENG]

Well, I’ve connected the Rotel RMB-1575 today and calibrated the system again with Audyssey.

As expected there is no sound difference whatsoever (that was not my goal) but the distortion is gone. That’s a relief.

Funny thing though, Audyssey set all my speakers 2db louder except for the Atmos speakers (closer to 0.0db in the AVR). I think the gain in the amp is lower than the Marantz.

I don’t have regrets buying this amp. It’s a great feeling having tons of headroom in my system now which is now distortion free. Later this week I’ll watch a couple of movies and listen to my multichannel SACD’s.

If you heard distortion using the 7011, then you really do listen loud and probably pass reference level. In that case, you should apply the amp assign trick so that at least the front left and right channel pre-outs would remain clean at the 2 V level that is needed for the less sensitive Rotel amp to just reach its rated output of 250 W into 8 ohms. Even the Marantz separate, namely the AV7705 did not do well at 2 V (ie. when measured 4 V via XLR) much worse than the Denon AVR-X3600H on the bench so I can't imagine the SR7011 could do better, likely worse logically speaking. It may be academic in practical sense, but the weird thing is that you hear distortion with when using the AVR.

 

[Kleinst]

I enoy picking up separates to go with my AVRs too. Are they needed? Hard to tell as for Most TV watching it’s probably not. It does seem to shine when I crank it up and it’s really clean. Truth also is that I enjoy collecting and building a great system... can We admit we as much fun seeking this stuff out as actually listening to it?

 

[PENG]

I enoy picking up separates to go with my AVRs too. Are they needed? Hard to tell as for Most TV watching it’s probably not. It does seem to shine when I crank it up and it’s really clean. Truth also is that I enjoy collecting and building a great system... can We admit we as much fun seeking this stuff out as actually listening to it?

In most cases it is more about "power" requirement than anything else if you have a mid level AVR such as D&M's X3000, comparable Marantz and Yamaha's RX-AX000 series models.

Let's say you need 60 W into 8 ohm, 90 W for the loudest peak in movies and music you listen to at you MMP, if your AVR is rated for 100 W into 8 ohms, then adding an external amp will not help in sound quality that is for the most part much more affected by the quality of recording, loudspeakers and their placement in a particular room.

I dare say most people will actually (that they would convince themselves) hear "better" sound quality for reasons including:

- They always wanted to do it, after reading subjective reviews, forum hearsay etc. that how the sound stage would open up, much more dynamic impacts, harshness gone etc etc, even night and day differences, so there's got to be at least some subtle but clearly audible difference from their new investment right? That is, expectation, Placebo are there waiting to help, and they rarely disappoint.

- Once they got their always wanted external amp, they would feel very good, proud, confident and ready for the sound quality improvements that they expected... Most would likely crank things up as they now have no fear of clipping, whether it would be speaker, amp or both clipping, and would immediate feel the impressive dynamic impacts on action and science fiction movies that previous they probably won't push their AVR that far, or if they did, they would back right off out of concerns of damaging any components.

I might have been describing my own experience, only after some time, one may realize what the real reasons are, but would still keep their amps or even continue to add and upgrade (I did..), but for reasons other than sound quality improvements. Many experienced audioholics must have similar experience to mine, but would we convince anyone, not likely but some appeared to have listened to some of us, and put their priorities on other things that matter more, without going through what we went through, while the majority really came and asked just to hear what they wanted to hear (support, confirmation..), and then went ahead and got impressed..

 

[IMWhizzle]

In most cases it is more about "power" requirement than anything else if you have a mid level AVR such as D&M's X3000, comparable Marantz and Yamaha's RX-AX000 series models.

Let's say you need 60 W into 8 ohm, 90 W for the loudest peak in movies and music you listen to at you MMP, if your AVR is rated for 100 W into 8 ohms, then adding an external amp will not help in sound quality that is for the most part much more affected by the quality of recording, loudspeakers and their placement in a particular room.

I dare say most people will actually (that they would convince themselves) hear "better" sound quality for reasons including:

- They always wanted to do it, after reading subjective reviews, forum hearsay etc. that how the sound stage would open up, much more dynamic impacts, harshness gone etc etc, even night and day differences, so there's got to be at least some subtle but clearly audible difference from their new investment right? That is, expectation, Placebo are there waiting to help, and they rarely disappoint.

- Once they got their always wanted external amp, they would feel very good, proud, confident and ready for the sound quality improvements that they expected... Most would likely crank things up as they now have no fear of clipping, whether it would be speaker, amp or both clipping, and would immediate feel the impressive dynamic impacts on action and science fiction movies that previous they probably won't push their AVR that far, or if they did, they would back right off out of concerns of damaging any components.

I might have been describing my own experience, only after some time, one may realize what the real reasons are, but would still keep their amps or even continue to add and upgrade (I did..), but for reasons other than sound quality improvements. Many experienced audioholics must have similar experience to mine, but would we convince anyone, not likely but some appeared to have listened to some of us, and put their priorities on other things that matter more, without going through what we went through, while the majority really came and asked just to hear what they wanted to hear (support, confirmation..), and then went ahead and got impressed..

I normally do agree with your above statement. For most people with an AVR connected to a 5.1 setup, it’s fine. But it’s a different story when one is connecting 9 speakers to the same AVR. Adding a power amp does improve the sound and yes, it’s a relief that I have enough power on tap and don’t have to worry about the volume knob. With the amp I can also extend the life of my speakers and AVR. In the near future when the HDMI 2.1 specification is settles I will go for a dedicated pre/pro and an additional amp for the atmos channels.

Music and movies are much more dynamic. That is the biggest advantage compared to the old setup. Mind you, there is no sound difference at normal listening levels. But the sound isn’t harsh anymore after turning up the volume, it still sounds perfectly balanced and easy for the ears. Most importantly, no distortion whatsoever. It’s gone.


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[PENG]

Music and movies are much more dynamic.

That's what I have difficulty with, "much more" ? With those Klipsch speakers (yes I knock their claimed 98 dB down to 92 dB sensitivity and you should still get 80 dB average spl and 100 dB peak (THX) from 10 ft with just one speaker and 0.6 W average, 60 W peak (for the 20 dB movie peaks) and no room gain assumed!!

If you listen to MCH stereo, you are going to tax the AVR more but then with 9 speakers all making sound you will get significant spl gains too. The AVR may struggle under such condition, but the Rotel amp is going to make just about 3 to 4 dB more headroom (turn the SR7011 volume down by 3 to 4 would fix that under such unusual conditions, very few people actually use MCH stereo on regular basis.

So "much more", especially in movies and SACD in non MCH ST listening would make 0 logical sense. Again, amps are good and that's why I have quite a few, but hearing such difference you described is something hard to explain base on known science about such matured product. There is an issue if you heard distortions from your surround speakers, and if that happened to me I would investigate until I find the real reason.

Adding a nice external amp such as the Rotel RMB-1575 is a good thing regardless. I would love to seem some measurements but iirc their old class AB amps performed fine on the benches, at least the old class AB ones, but I don't recall seeing any measurements for their newer class D amps.

 

[TLS Guy]

That's what I have difficulty with, "much more" ? With those Klipsch speakers (yes I knock their claimed 98 dB down to 92 dB sensitivity and you should still get 80 dB average spl and 100 dB peak (THX) from 10 ft with just one speaker and 0.6 W average, 60 W peak (for the 20 dB movie peaks) and no room gain assumed!!

If you listen to MCH stereo, you are going to tax the AVR more but then with 9 speakers all making sound you will get significant spl gains too. The AVR may struggle under such condition, but the Rotel amp is going to make just about 3 to 4 dB more headroom (turn the SR7011 volume down by 3 to 4 would fix that under such unusual conditions, very few people actually use MCH stereo on regular basis.

So "much more", especially in movies and SACD in non MCH ST listening would make 0 logical sense. Again, amps are good and that's why I have quite a few, but hearing such difference you described is something hard to explain base on known science about such matured product. There is an issue if you heard distortions from your surround speakers, and if that happened to me I would investigate until I find the real reason.

Adding a nice external amp such as the Rotel RMB-1575 is a good thing regardless. I would love to seem some measurements but iirc their old class AB amps performed fine on the benches, at least the old class AB ones, but I don't recall seeing any measurements for their newer class D amps.

Honestly Peng, I think you have an over "rosy" view of the capability of current receivers. That Marantz 5103 I installed recently was really worthless in the power amp department.

It was all ELAC speakers and a couple of HSU subs. You really cold not push that system hard at all without it sounding "gritty" and well the wrong side of pleasant and it got worrying hot, despite not being restricted at all. I certainly know by now the sound of distressed amps. I'm pretty sure I could have given that receiver a pretty short life.

Fortunately the couple just want a good TV system, and are content not to push it.

I really think that for any "serious" system the power amps in that receiver were pretty worthless.

If we are gong to use receivers to power decent systems, they need to be able to run four ohm loads to the front three simultaneously at 100 watts each and at least 40 to 50 watts to the other channels at the same time. Otherwise they really are basically "toys" and not fit for the serious enthusiast.

 

[AcuDefTechGuy]

A subwoofer takes off the low end load of a receiver or amplifier. Please explain how this isn't making the load on a receiver or amp much lighter. It's the low heavy frequencies that require power, not treble. If you are using a cutoff frequency of 100 hz, that would be taking quite a load of of any amp/receiver.

Assuming the person is not using LFE+Main or “Double Bass” which outputs full bass to both Towers and Subs, yeah if the person is setting speakers to Small and using LFE (XO 80-120 Hz), that should help reduce the power requirements in the AVR.

 

[AcuDefTechGuy]

If we are gong to use receivers to power decent systems, they need to be able to run four ohm loads to the front three simultaneously at 100 watts each and at least 40 to 50 watts to the other channels at the same time. Otherwise they really are basically "toys" and not fit for the serious enthusiast.

You think the discrete Center Dialogue channel requires 100W Continuous power for most people who listens to an average volume of 80dB and sits about 12FT away using speakers with sensitivity of at least 85dB/2.83v/m?

 

[PENG]

Honestly Peng, I think you have an over "rosy" view of the capability of current receivers. That Marantz 5103 I installed recently was really worthless in the power amp department.

Not really, I was trained to rely only on facts and numbers. What I stated, were based on calculated and/or measured results, if not I would have said so. For example, how is it logical for "power" not used, I mean under the worst practical conditions would make a difference. You have a Marantz AV now, that does not have specs and/or known measurements that it would be better than the AVR-X3600H (yes that's a lower end receiver) if it is used as a pre-pro with a 200 W power amp, even without the amp assign heck, but for you, you probably won't believe it just because it is just an AVR.

By the way, someone who actually admitted he hear better "sound quality" (not in so many word, could find it and quote exact but that's ok..) after installing an auto REQ system (the supposedly better one, not Audyssey), only to realize quickly he hadn't even uploaded the program. Placebo is real, of all people you must know that right Dr.? I'll admit, it (Placebo) doesn't work the same way in audio stuff.

 

[Paul DS]

No you don't need to buy any amps. The Marantz AVR is powerful enough for your Klipsch.

Assuming the person is not using LFE+Main or “Double Bass” which outputs full bass to both Towers and Subs, yeah if the person is setting speakers to Small and using LFE (XO 80-120 Hz), that should help reduce the power requirements in the AVR.

I use LFE+Main and I use a set of Tekton Double Impact Speakers for front L/R, and a Klipsch RP500C Center. Front L/R set to LARGE. I use a Denon AVRX4400H receiver set to 4 ohm. It can bring sound up to thundering levels. I certainly don't require any extra amplification.

 

[PENG]

I use LFE+Main and I use a set of Tekton Double Impact Speakers for front L/R, and a Klipsch RP500C Center. Front L/R set to LARGE. I use a Denon AVRX4400H receiver set to 4 ohm. It can bring sound up to thundering levels. I certainly don't require any extra amplification.

Those have good sensitivity, despite being 4 ohm nominal. There is always the option to set the receiver to 8 ohm but place two 120 mm Infinity fans on top.

 

[Paul DS]

Those have good sensitivity, despite being 4 ohm nominal. There is always the option to set the receiver to 8 ohm but place two 120 mm Infinity fans on top.

When set to 8 ohms the receiver becomes very hot. No reason to do that as the 4 ohm setting gives me all the power I could possibly use and runs cool as a cucumber.

 

[PENG]

When set to 8 ohms the receiver becomes very hot. No reason to do that as the 4 ohm setting gives me all the power I could possibly use and runs cool as a cucumber.

Of course, that's why I suggested two fans if the 8 ohm setting is used. Well then okay as I am sure you know when the 4 ohm setting is used, your receiver output drops significantly, limited by the rail voltage. I guess you don't sit too far from those big speakers then.

 

[Paul DS]

Of course, that's why I suggested two fans if the 8 ohm setting is used. Well then okay as I am sure you know when the 4 ohm setting is used, your receiver output drops significantly, limited by the rail voltage. I guess you don't sit too far from those big speakers then.

It is an 18 X 20 room. I sit about 14 feet from the speakers. Just no need for more power. People are running the Double Impact speakers with 20 watt tube amps. Heat is the enemy of electronics. If I set the receiver to 8 ohms, it is putting a very large load on the electronics. I would have to assume that it would shorten the lifespan of the receiver considerably. I am also running two Dayton 12" subs to complement bass output. The system is capable of some very powerful bass output.

 

[Pogre]

I normally do agree with your above statement. For most people with an AVR connected to a 5.1 setup, it’s fine. But it’s a different story when one is connecting 9 speakers to the same AVR. Adding a power amp does improve the sound and yes, it’s a relief that I have enough power on tap and don’t have to worry about the volume knob. With the amp I can also extend the life of my speakers and AVR. In the near future when the HDMI 2.1 specification is settles I will go for a dedicated pre/pro and an additional amp for the atmos channels.

Music and movies are much more dynamic. That is the biggest advantage compared to the old setup. Mind you, there is no sound difference at normal listening levels. But the sound isn’t harsh anymore after turning up the volume, it still sounds perfectly balanced and easy for the ears. Most importantly, no distortion whatsoever. It’s gone.


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I'm on board with the warm fuzzies I get from knowing I have gobs of power on tap, but I don't notice any differences that I can remember with any reliability in sound quality between my SR6011 and my Monolith 7 amp. It doesn't matter how many speakers you have hooked up unless you have all 9 turned up very loud and they're all playing the same signal simultaneously. I don't know of much content like that and most folks listen to music in stereo, which makes the number of speakers irrelevant.

I agree with Peng and I gotta say he did a great job of describing some of my own personal experiences in the beginning. Expectation bias and the placebo effect are very real, and detailed audio memory in humans is very fleeting (.003-.005 seconds I believe?). There's more that goes into accurately doing comparisons like that than most realize. You need to remove sighted biases, level match with a spl meter, make sure dsp is disengaged, etc.

Sometimes I swear my speakers sound better after I polish them up, lol.