Separate power amp needed with 5.2.4 setup?

[Auditor55]

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 still trying to figure out what's so special about 2.1 for an audiophile?

 

[lovinthehd]

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.

I think you're over negative on a number of things, avrs included. They're not power amps as you say, never were meant to be IMO. They work perfectly fine for most uses. Which is what they're aiming at I think. ELAC speakers from what I have read are generally low impedance loads and difficult tor drive....so despite their bargain appearance may not be ideal for some who wish elevated levels from an avr with such speakers. Tools for the job and all that. Pre-outs can be useful.

 

[PENG]

I think you're over negative on a number of things, avrs included. They're not power amps as you say, never were meant to be IMO. They work perfectly fine for most uses. Which is what they're aiming at I think. ELAC speakers from what I have read are generally low impedance loads and difficult tor drive....so despite their bargain appearance may not be ideal for some who wish elevated levels from an avr with such speakers. Tools for the job and all that. Pre-outs can be useful.

We have been over this more than once before and we know it may never be possible to convince someone who is so against receivers (more so AVRs) in general or even as a rule, that the internal amps of AVRs can be effective and work well for many potential home HT and even 2 channel system users.

For TLSGuy, I think I have even provided a link for him to read a British measurement site that shows my >10 years old Denon AVR-3805 that only weights about 35 lbs actually passed the 1 ohm test when many real power amps failed.

Also, as you well know, It seems that most people are still stuck on the all channel driven thing so when they see 7 or 9 amps in a 30 lb receiver, they would jump to the conclusion that they need at least a 3 channel power amp, when in most many cases those people would listen to at least 5 dB below "reference" and their AVR (such as the SR7xxx/AVR-X4000h can do the job with plenty of headroom. I don't know how many times we will be answering questions about "do I need an amp..", and then they would go ahead anyway in anticipation of hearing things they never heard before, but to realize what they'd miss before..lol.. May be we can find a way, or at leas a FAQ thread worded in such a way that people will find if they do a simple keyword search. Can I volunteer you or @AcuDefTechGuy (he's very good at starting threads that remains active for a long time.....) I mean how about just consider it an experiment guys..?

 

[AcuDefTechGuy]

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.

Although I've always used separates for my main systems, I've always used AVRs for my secondary systems which include 5.1 speaker systems that "dip below 3 ohms".

I think about 99% of the systems out there (which means about 99% AVR vs 1% separates ) don't actually need external amps. But they may need external fans since a lot of AVRs operate at extremely HOT temp (except Yamaha operate the coolest temp ).

I've never had an AVR shut down due to inadequate power, but I've had AVR shut down due to overheating (even in open ventilated rack system, A/C in room).

I think my point is that IF there were a rare case where you truly needed external amps, the "Double-Bass/LFE+Main/Setting speakers to Full Range and using MCH Stereo mode" might be a reason.

However, I'm sure there are many more cases where you could use "9Ch Stereo Mode + Large Full Range speakers + Double-Bass/LFE+Main" and still not need any external amp.

 

[Auditor55]

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.

Your ears might require extra if you keep listening at thunderous levels.

 

[Paul DS]

Your ears might require extra if you keep listening at thunderous levels.

What makes you think I listen at thunderous levels? I said it is possible to turn the system quite loud, I don't play it at anywhere near reference levels.

 

[AcuDefTechGuy]

We have been over this more than once before and we know it may never be possible to convince someone who is so against receivers (more so AVRs) in general or even as a rule, that the internal amps of AVRs can be effective and work well for many potential home HT and even 2 channel system users.

For TLSGuy, I think I have even provided a link for him to read a British measurement site that shows my >10 years old Denon AVR-3805 that only weights about 35 lbs actually passed the 1 ohm test when many real power amps failed.

Also, as you well know, It seems that most people are still stuck on the all channel driven thing so when they see 7 or 9 amps in a 30 lb receiver, they would jump to the conclusion that they need at least a 3 channel power amp, when in most many cases those people would listen to at least 5 dB below "reference" and their AVR (such as the SR7xxx/AVR-X4000h can do the job with plenty of headroom. I don't know how many times we will be answering questions about "do I need an amp..", and then they would go ahead anyway in anticipation of hearing things they never heard before, but to realize what they'd miss before..lol.. May be we can find a way, or at leas a FAQ thread worded in such a way that people will find if they do a simple keyword search. Can I volunteer you or @AcuDefTechGuy (he's very good at starting threads that remains active for a long time.....) I mean how about just consider it an experiment guys..?

I think a FEW people (1%) are stuck on over-exaggerating and over-complicating things that could be EXTREMELY SIMPLE.

The rest of the population, like maybe 99% of the population who simply use single-solution-AVRs, have absolutely no problem at all even when they are using 9CH Stereo Mode - they just simply sit back at the end of the day and enjoy the heck out of their simple systems without losing any sleep over it.

 

[Paul DS]

Although I've always used separates for my main systems, I've always used AVRs for my secondary systems which include 5.1 speaker systems that "dip below 3 ohms".

I think about 99% of the systems out there (which means about 99% AVR vs 1% separates ) don't actually need external amps. But they may need external fans since a lot of AVRs operate at extremely HOT temp (except Yamaha operate the coolest temp ).

I've never had an AVR shut down due to inadequate power, but I've had AVR shut down due to overheating (even in open ventilated rack system, A/C in room).

I think my point is that IF there were a rare case where you truly needed external amps, the "Double-Bass/LFE+Main/Setting speakers to Full Range and using MCH Stereo mode" might be a reason.

However, I'm sure there are many more cases where you could use "9Ch Stereo Mode + Large Full Range speakers + Double-Bass/LFE+Main" and still not need any external amp.

I think that in many cases, if a receiver is getting too hot, it's a good chance that 4 ohm speakers are being used with the avr set at 8 ohms. My Denon avrx4400h runs very hot, if have it set to 8 ohms. Most of my speakers are 4 ohm. When I have the receiver set to 4 ohms, it is as cool as a cucumber. It have more than enough power for my requirements at the 4 ohm setting.

 

[AcuDefTechGuy]

I think my Bose system require 1,000W McIntosh amps to sound their best.

 

[AcuDefTechGuy]

I think that in many cases, if a receiver is getting too hot, it's a good chance that 4 ohm speakers are being used with the avr set at 8 ohms. My Denon avrx4400h runs very hot, if have it set to 8 ohms. Most of my speakers are 4 ohm. When I have the receiver set to 4 ohms, it is as cool as a cucumber. It have more than enough power for my requirements at the 4 ohm setting.

Hmm, interesting. All the Denon's I've used were older models and I don't recall having the option of setting the impedance.

But that's a great point about not needing this Generation-OVERKILL power.

Yeah, if the 4-ohm setting keeps your AVR cool, then I think that's the best setting.

 

[PENG]

Hmm, interesting. All the Denon's I've used were older models and I don't recall having the option of setting the impedance.

But that's a great point about not needing this Generation-OVERKILL power.

Yeah, if the 4-ohm setting keeps your AVR cool, then I think that's the best setting.

It does because like ECO it lowers the rail voltage. It also means power will be reduced significantly because of the lower voltage, but for people like me who listen to 75 dB average sitting under 11 ft, the AVR would output about 0.15 W average, or 15 W peak for the 20 dB peaks in movies that go by the THX standard, then the 4 ohm setting can be a good solution instead of external fans. But too bad I use external amps anyway, have ECO "ON" and still put fans on top.

 

[Auditor55]

I think a FEW people (1%) are stuck on over-exaggerating and over-complicating things that could be EXTREMELY SIMPLE.

The rest of the population, like maybe 99% of the population who simply use single-solution-AVRs, have absolutely no problem at all even when they are using 9CH Stereo Mode - they just simply sit back at the end of the day and enjoy the heck out of their simple systems without losing any sleep over it.

People just like spending their disposal income, logic/reason be damned.

 

[AcuDefTechGuy]

People just like spending their disposal income, logic/reason be damned.

Well, we all know how fun it can be to spend money...

I love Atmos/NeuralX, but I will also say that your system can sound awesome without Atmos.

I love separates, but I will also say that your system can sound awesome with AVRs.

 

[IMWhizzle]

I think this topic will always remain a can of worms. Opinions about receivers vs separates will remain. I appreciate all the advise and technical knowledge, that’s why I joined this site. I indeed went ahead and bought the Rotel RMB-1575.

The main reason is to have the headroom available whenever I need it. I’ve stated before that I was hearing distortion several times when the system played 5db below reference. There are too many factors in play. I also told that the Atmos speakers have another sensitivity rating than my main speakers. The difference was 5db between them as Audyssey set them that way. As opinions remain different I’ve decided to buy the amp. I got the chance to buy a brand new sealed model for 1000 euros and a two year warranty. That’s not expensive for a powerful multichannel amp, so why not try it? Reason is that the 1575 was replaced by the 1585 which is now almost 3000 euros.

Distortion is now gone, the sound is clean. Dynamics are amazing, it’s not a placebo effect. It’s a big difference when playing loud. Also in the long term I can buy midrange receivers and use them as a pre pro to get the features I need for cheap without sacrificing sound quality. The Denon 3600 for example meassured better than the Marantz 7705 on the pre outs for example and I’ll get eARC which the 7011 lacks. The amp is an investment which conserves my equipment in the long term.

Yes my speakers are sensitive, but that doesn’t mean that I should take the risk to underpowered them. It’s better to feed them more power than the other way around. I have spent a good amount of money on them and I would like to use their full potential when playing a multichannel SACD in full range for example.

 

[Pogre]

it’s not a placebo effect.

You haven't come close to doing a proper enough evaluation (dbt) to even make that determination! Ha ha.

Regardless, I believe you when you say you hear a difference and that's all that counts. Glad you're happy. There's nothing wrong with buying an amp, we just try to give folks an idea of what to expect, based on experiences. The rest is up to the buyer. I bought an amp too, but for different reasons.

 

[Verdinut]

You haven't come close to doing a proper enough evaluation (dbt) to even make that determination! Ha ha.

Regardless, I believe you when you say you hear a difference and that's all that counts. Glad you're happy. There's nothing wrong with buying an amp, we just try to give folks an idea of what to expect, based on experiences. The rest is up to the buyer. I bought an amp too, but for different reasons.

Yeah, you were curious and you wanted to find the answer by yourself and also benefit from the pride of ownership, right?

 

[Pogre]

Yeah, you were curious and you wanted to find the answer by yourself and also benefit from the pride of ownership, right?

Sure, and my receiver runs a little cooler now, I have plenty of headroom, room for expansion or the occasional difficult to drive speakers... and pride of ownership is a big one. Lots of reasons. I've wanted big, high quality speakers and gear before I even understood what half of it did, lol.

I knew going in tho, not to expect any big obvious audible improvements from my amp before I pulled the trigger. I have lower sensitivity speakers (88 dB), doubled my power, even bi amped my speakers and (even tho I wish there was) I can't detect any significant differences.

 

[PENG]

I think this topic will always remain a can of worms. Opinions about receivers vs separates will remain. I appreciate all the advise and technical knowledge, that’s why I joined this site. I indeed went ahead and bought the Rotel RMB-1575.

The main reason is to have the headroom available whenever I need it. I’ve stated before that I was hearing distortion several times when the system played 5db below reference. There are too many factors in play. I also told that the Atmos speakers have another sensitivity rating than my main speakers. The difference was 5db between them as Audyssey set them that way. As opinions remain different I’ve decided to buy the amp. I got the chance to buy a brand new sealed model for 1000 euros and a two year warranty. That’s not expensive for a powerful multichannel amp, so why not try it? Reason is that the 1575 was replaced by the 1585 which is now almost 3000 euros.

Distortion is now gone, the sound is clean. Dynamics are amazing, it’s not a placebo effect. It’s a big difference when playing loud. Also in the long term I can buy midrange receivers and use them as a pre pro to get the features I need for cheap without sacrificing sound quality. The Denon 3600 for example meassured better than the Marantz 7705 on the pre outs for example and I’ll get eARC which the 7011 lacks. The amp is an investment which conserves my equipment in the long term.

Yes my speakers are sensitive, but that doesn’t mean that I should take the risk to underpowered them. It’s better to feed them more power than the other way around. I have spent a good amount of money on them and I would like to use their full potential when playing a multichannel SACD in full range for example.

Your comments are much appreciated, as you never did make any groundless claim like many others have..
To summarize what we know so far regarding your case:

- Your main speakers are quite sensitive, but I would estimate 92 dB/2.83V, not the claimed 98 dB
- Your surround speakers have no sensitivity specs
- Audyssey set the surrounds 5 dB lower, so if you can provide your seating distance from them, I can give you a pretty accurate sensitivity relative to the mains, but it does look like they would be around 87 +/- 2 dB/2.83V

So if you played contents that frequently peaked to >95 dB spl from where you sit then you would likely hear audible distortions due to the Marantz amp clipping based on available measurements.

May be a simple test to show if power output at clipping is the issue, is to turn the volume up until you hear the same distortions from the same speaker under the same conditions, that is, where you sit and the contents you played. Then compare that to where the volume was when using the AVR. Obviously you have to compensate for Rotel's 2 dB lower gain. The expected difference would be 5 to 7 dB. That is, if it clipped at 0 with the AVR, then it would be +5 to +7 with the Rotel amp.

To be clear, my Placebo comment was not directed to you (was just a general remark) because you have actually heard distortions with the AVR but not with the amp added. I am just skeptical about the real root cause, to the point I wish I could be there to troubleshoot it. That's just me, and I have always been much more curious and determined than most of my colleagues and subordinate while at work, and had often found the root causes of many seemingly mysterious faults that were only discovered when I went and did it myself. Normal people would, and in many cases should, just move on and enjoy life.