Separate power amp needed with 5.2.4 setup?

[IMWhizzle]

Hi all,

This will be my first post, please be gentle with me.

At the moment I have four Klipsch RP280F's (Fronts and Surrounds), a Klipsch RP450C center, 4x RP-500SA’s atmos speakers and two Klipsch R-115SW subwoofers, powered by a Marantz 7011 AV Receiver. I know my speakers are fairly efficient (not the 98db that Klipsch claims though) but I don't know for certain if the receiver can handle this without sacrificing the sound quality. It‘s driving 9 channels at once and is doing all the processing and whatnot. I don't listen to reference levels, but about -10dB to -5dB below reference (mostly Disney content) volume is often used. My MLP is about 10ft from the LCR and my room is 45m2.

I’ve checked the room respone with REW after an Audyssey calibration (limit correction to 300hz). Strange enough the best bass response is with a crossover setting of 110hz. Is it that a higher crossover to the subwoofers is giving the receiver more power on tap? Only then the speakers opened up mids and the highs. The soundstage is much better too. I can’t help but wonder if an additional power amp would benefit my system. I’ve narrowed down my choice to the Rotel RMB 1585, which I got a very good deal for.

Is an external amplifier needed connected to the pre outs of my Marantz 7011 or not?

I hope one can help me out with the above.

 

[Verdinut]

Welcome to AH,

Do you find that, at the -5 dB volume level, your SR5011 struggles to provide a clean sound? Your Klipsch speakers are rather efficient with a sensitivity of around 94 dB, your 45 m2 room is an average area, and you're sitting about 10 feet from the front speakers..

I strongly doubt that your AVR cannot cope with the demand. Fixing the crossover at 110 Hz relieves some power demand on it as well. I suggest that you try the following link to calculate how much power you need to reach your preferred SPL. Bear in mind that only the 3 front channels require most of the power, the power required for all the surround channels is quite less for all practical purposes, unless you were using the all channel stereo feature.

Peak SPL Calculator

 

[PENG]

The R-820F sensitivity spec is 97 dB/2.83V/M, measured only 92.43 dB.
The R-280F spec is 98 dB so I would assume its actual measured value would be about 92 dB.

I just tried my new calculator and you can see from below that you should only need 0.6 W per speaker to produce your 80 dB average (you said 5 dB below ref) requirement. That is very conservative as I have not enter in any room gain in the calculator. So even to cover the THX specified 20 dB peak requirement, you still won't need any more than 60 W for one speaker.

If you have run Audyssey, I am curious what it did to your level settings. I suspect they will be close to -10 dB, due to the high speaker sensitivity for your 10 ft seating distance.

 

[IMWhizzle]

Thank you for looking into it. Very useful information. So I won’t benefit pairing a multichannel power amp to my speakers, or if I do it doesn’t need to be that powerful. So an Emotiva A-700 would suffice so to speak? That would be 80 clean watts with all channels driven.

The only thing I need to know is how much watts is going to every speaker on my current setup. The only rating I could find was the following bench test with the Marantz 7011 only:

Test Bench
Two channels driven continuously into 8-ohm loads:
0.1% distortion at 138.7 watts
1% distortion at 169.1 watts

Five channels driven continuously into 8-ohm loads:
0.1% distortion at 104.9 watts
1% distortion at 117.0 watts

Seven channels driven continuously into 8-ohm loads:
0.1% distortion at 75.1 watts
1% distortion at 90.4 watts

9 channels is not specified, but it could be 50 or 60 watts or so. The other reason I wanted to go for a separate amplifier is futureproof my purchase so I can benefit from the system for many years to come. Maybe I can even buy a processor to go with it in the future.

 

[Verdinut]

Thank you for looking into it. Very useful information. So I won’t benefit pairing a multichannel power amp to my speakers, or if I do it doesn’t need to be that powerful. So an Emotiva A-700 would suffice so to speak? That would be 80 clean watts with all channels driven.



9 channels is not specified, but it could be 50 or 60 watts or so. The other reason I wanted to go for a separate amplifier is futureproof my purchase so I can benefit from the system for many years to come. Maybe I can even buy a processor to go with it in the future.

If you want to power your 3 front channels with external amplification to obtain more headroom, I don't recommend the Emotiva brand which doesn't have a reliable record. I would suggest the Monoprice Monolith 3 channel amp. Three Outlaw 2200M monoblocks would also be an excellent option. These are more powerful than the Emotiva, but they are future proof.

Parasound A23+ vs. Emotiva XPA-DR2

I know - doesn't seem like a fair comparison right? Putting together a modest 2 channel system, considering these two power amps. Would you take the A23+, 160w/ch with better sound staging, detail, clarity? Would you go with the DR2, 550w/ch with more grunt, punch and dynamics? Speakers for...

forums.audioholics.com

Marantz guarantee for the surround channels, a rated output of 70% of the 2 channel power rating on your AVR. Bear in mind that is amply sufficient for your surround channel needs. As a matter of fact, for all practical purposes, most of the amp power is required for the 3 front channels. The power required for surround is a lot less and the 7011 provides less than 2 dB inferior power as compared to the 2 channel rating for your surround speakers. There's no reason to question its capability.

 

[lovinthehd]

The amount of power that goes to each channel is different from the power available to each channel, depends on use. There's no advantage to the A-700 except perhaps taking heat out of the avr, but for power its pretty much the same thing.

 

[IMWhizzle]

If you want to power your 3 front channels with external amplification to obtain more headroom, I don't recommend the Emotiva brand which doesn't have a reliable record. I would suggest the Monoprice Monolith 3 channel amp. Three Outlaw 2200M monoblocks would also be an excellent option. These are more powerful than the Emotiva, but they are future proof.

Parasound A23+ vs. Emotiva XPA-DR2

I know - doesn't seem like a fair comparison right? Putting together a modest 2 channel system, considering these two power amps. Would you take the A23+, 160w/ch with better sound staging, detail, clarity? Would you go with the DR2, 550w/ch with more grunt, punch and dynamics? Speakers for...

forums.audioholics.com

Marantz guarantee for the surround channels, a rated output of 70% of the 2 channel power rating on your AVR. Bear in mind that is amply sufficient for your surround channel needs. As a matter of fact, for all practical purposes, most of the amp power is required for the 3 front channels. The power required for surround is a lot less and the 7011 provides less than 2 dB inferior power as compared to the 2 channel rating for your surround speakers. There's no reason to question its capability.

Hi unfortunately the brands you mentioned are not available in the Netherlands. Three channel amps are not available here, except for the Emotiva XPA-3 which I can buy from a vendor in Germany. The only powerful amp which I can buy for “cheap“ are the Marantz 8077 and the Rotel 1575 (the model before the 1585). The Rotel 1575 is 250watts all channels driven. That’s more than enough headroom en gives my flexibility to play with lower crossovers. I did not take the plunge yet I wanted to be schooled by fellow members on this community first. Maybe I oversee things.

 

[PENG]

Strange enough the best bass response is with a crossover setting of 110hz. Is it that a higher crossover to the subwoofers is giving the receiver more power on tap?

Only then the speakers opened up mids and the highs. The soundstage is much better too.

You've got that right, REW has told you the truth! It is not always the case as it depends a lot on your speakers, placement and the room, but probably more often that not, that higher crossover settings would minimize interference between the low frequencies produced by bass capable towers like yours, and the subwoofers.

I can’t help but wonder if an additional power amp would benefit my system. I’ve narrowed down my choice to the Rotel RMB 1585, which I got a very good deal for.

Based on measurements I have seen on various Marantz AVRs and some Rotel amps, I am almost certain that you won't be able to hear a difference with or without the Rotel. No offense, you likely can "see" the difference, based on your perception of hearing the speakers "opened up mids and the highs..soundstage much better..." etc., that you may be prone to the Placebo effects. Just seeing that there is a separate power amp hooked, especially a Rotel, you have to hear things..

Is an external amplifier needed connected to the pre outs of my Marantz 7011 or not?

I hope one can help me out with the above.

Honest answer, no.., yes we, the more numbers driven bunch would always try to help based on known facts and data, but quite often people would do it anyway, as subjective reviews can be very convincing. The fact is, you have a very capable SR7011 and quite sensitive speakers, so audible benefits can be expected if your system is still needing more "power". Given the information you have provided so far, you do have enough power on hand. You can see the details in the calculated results I posted in post#3. Just one of your main speaker can give you the spl you need with about half a watt (the 0.59 W as shown is a very conservative number. So I would say when watching a movie at 10 dB below reference, you SR7011 would be outputting less than 0.5 W average and may be up to 60 W peak so you actually have some healthy headroom on hand with just the AVR.

 

[IMWhizzle]

Thank you for your post.

When I wrote about a better soundstage and better mids and highs, I was reffering to higher crossover. I think it’s because of the blend between the subs and the towers as you stated. Apart from the 110hz crossover, a 40hz and 60hz crossover for the towers also resulted in a clean blend according to REW. 80hz and 90hz are showing afwful dips around that area. I didn’t settle for the lower crossovers, because I was not sure if that would be healthy for the system. But now I think I can because of the explanation above.

I didn’t buy a power amp yet. I just narrowed my choice down to the rotel, but reading your posts and summing up the advice from others, I am glad that I don’t need to buy extra components which saves me a lot of money. Thank you for the detailed explanation.

In post #3 you mentioned the trim levels of the speakers which could be set according to you on -10db. Audyssey set the left and right speakers both on -4.5db.

 

[IMWhizzle]

Today I’ve heard the right surround speaker clipping when watching the opening of a transformers movie with the volume on -5db below reference. To make sure it wasn’t a blown speaker I played the part back a couple of times and the moments I hear that sound were different than the first time. It was not a hard sound, but moderate. This was not the case before adding my Atmos speakers which have higher level trims in the AVR than the bed channels. That means they are less efficient than the other speakers.

I think I will buy an amp to give my speakers more breathing space. There are too many variables which can cause this issue. Also I don’t want to worry about the volume knob and I do want to listen to music all channels stereo if I feel like it. Also I think it’s a good idea to lengthen the life of my speakers and other gear. Eventually I will buy a processor instead of an av receiver.

Thanks for all the help and insights. I’m going for a one box solution, namely the Emotiva XPA-9.

 

[TLS Guy]

Today I’ve heard the right surround speaker clipping when watching the opening of a transformers movie with the volume on -5db below reference. To make sure it wasn’t a blown speaker I played the part back a couple of times and the moments I hear that sound were different than the first time. It was not a hard sound, but moderate. This was not the case before adding my Atmos speakers which have higher level trims in the AVR than the bed channels. That means they are less efficient than the other speakers.

I think I will buy an amp to give my speakers more breathing space. There are too many variables which can cause this issue. Also I don’t want to worry about the volume knob and I do want to listen to music all channels stereo if I feel like it. Also I think it’s a good idea to lengthen the life of my speakers and other gear. Eventually I will buy a processor instead of an av receiver.

Thanks for all the help and insights. I’m going for a one box solution, namely the Emotiva XPA-9.

That is the right choice.

Your speakers are rated 8 ohm compatible, which is meaningless. From the design they will be four ohm. Klipsch are well known for padding their sensitivity ratings. More to the point they are a definite polar response because of the horn. So they have more forward sound. So a directional speaker will seem more sensitive on test because more of the sound is directed at the mic. On the other hand a speaker with a wide off axis linear response will actually deliver more sound to the room for the same sensitivity. Unless you take sensitivity into account with the polar response of a speaker you will be seriously miss led.

Next your receiver does not have a four ohm rating. These days that is indefensible for any power amplifying device. The fact is that modern receivers with may be the exception of some Yamaha receivers, struggle to drive most speakers.

I have come to the conclusion that most current receivers are only fit to power small bookshelf speakers that are actually above four ohms in the power band in a very small room.

So I am in no doubt you heard that receiver clip.

I suspect a decent amp will correct it. But don't bank in the fact the other channels won't clip. Receivers are basically now for low volume listening, or at least not concert or reference volumes. Now there are more channels and facilities added this is a critical issue. The power amps took the back seat to maintain price points!

 

[IMWhizzle]

That is the right choice.

Your speakers are rated 8 ohm compatible, which is meaningless. From the design they will be four ohm. Klipsch are well known for padding their sensitivity ratings. More to the point they are a definite polar response because of the horn. So they have more forward sound. So a directional speaker will seem more sensitive on test because more of the sound is directed at the mic. On the other hand a speaker with a wide off axis linear response will actually deliver more sound to the room for the same sensitivity. Unless you take sensitivity into account with the polar response of a speaker you will be seriously miss led.

Next your receiver does not have a four ohm rating. These days that is indefensible for any power amplifying device. The fact is that modern receivers with may be the exception of some Yamaha receivers, struggle to drive most speakers.

I have come to the conclusion that most current receivers are only fit to power small bookshelf speakers that are actually above four ohms in the power band in a very small room.

So I am in no doubt you heard that receiver clip.

I suspect a decent amp will correct it. But don't bank in the fact the other channels won't clip. Receivers are basically now for low volume listening, or at least not concert or reference volumes. Now there are more channels and facilities added this is a critical issue. The power amps took the back seat to maintain price points!

Thank you for your detailed explanation. Which European multichannel amps do you advise? I’ve looked into the following options:

Marantz MM8077
Emotiva XPA-9 (one box solution, but 65 watts for Atmos speakers? I use the Klipsch RP-500SA’s and use them as DEAS.
Rotel RMB-1585
Yamaha MX-A5000 or MX-5200 (one box solution)

 

[TLS Guy]

Thank you for your detailed explanation. Which European multichannel amps do you advise? I’ve looked into the following options:

Marantz MM8077
Emotiva XPA-9 (one box solution, but 65 watts for Atmos speakers? I use the Klipsch RP-500SA’s and use them as DEAS.
Rotel RMB-1585
Yamaha MX-A5000 or MX-5200 (one box solution)

I'm not convinced a boat load of amps in one box is a good idea.

What you might want to do is think about using a good three channel one for the front three and let the receiver power the rest.

Other wise to use 2 channel amps. Now we have all these channels to worrya bout powering, I think you can make a good case for rack mounted 2 channel amps, like those from Crown or QSC and neatly rack mount them. They are class D, but in home theater that is not such a bad idea as it is energy efficient. It also is more cost effective.

Using two channel power amps of good pedigree is ideal, however it takes a lot of space, and requires attention to powering and cooling.

The engineering problem is quite significant. That is my room when it was under construction.

To do this properly requires and amp controller, with a system of 24 volt starting relays, magnetic shunt breakers and a quiet air extraction system for cooling.

A robust and reliable separate system for 9 channels, especially if you are externally powering the subs, is a very arduous and complex engineering proposition.
They don't tell you all that in the ads and mags.

The number of amps we have now in receivers is absolute insanity. So either of the solutions I mentioned make some sense, especially using a neat and tidy installation with class D pro amps makes a lot of sense.

Doing a really robust 7.2.4 or bigger system is now I feel well beyond the scope and expertise of the average consumer enthusiast. I think this is going to lead to a lot of sore heads and grief, mainly due to reliability issues.

A good 2.1 or 3.1 system starts to look a better and better prospect all the time, when you count all the real costs which are far from just measured in dollars, cents, Euros or pounds.

 

[IMWhizzle]

Thank you. Unfortunately how much I would like to stack a bunch of Crowns, it’s not an option since the system is in a living room. I am looking for a one box solution. Three channel amps are not available in the Netherlands. Emotiva is not an option anymore.

Audyssey set the level trims of the DAES speakers 5db higher than the bed channels. I’ve double checked the levels with REW and they are level matched correctly with all the channels in the system.

Still, I have not bought a multichannel amp yet, because of the poor choices we have in the Netherlands. I can only choose between:

Rotel 1575 (can buy it for 1100 euros new)
Marantz 8077
Rotel 1585
Yamaha MX-A5000/5200

I am leaning towards the Marantz, off course because of the same make as my receiver. But I can’t find a lot of experiences of that machine online. The Rotel 1575 has bad reviews from users and others like it. To many subjective opinions.

My goal is to buy a model which can last for a long time to come. I am planning to buy a pre/pro somewhere in the near future. So at the moment the priority is to choose an amp which should be a set and forget purchase. I want a good amount of headroom and don’t want to worry about the volume knob. Also I am looking for a one box solution which can be perfectly paired with my speakers (150 RMS nominal, 600 peak I think). I am not looking for a “warm” sound, just a pure amplifier with a low noise floor and can fulfill my needs for movies and music (music in “Dolby Surround” mode always).

Outlaw and Monolith are unfortunately not available in The Netherlands. Importing those models are a headache because of customs and shipping costs for one.

I would appreciate some advise which multichannel amp is best for my setup.

 

[TLS Guy]

Thank you. Unfortunately how much I would like to stack a bunch of Crowns, it’s not an option since the system is in a living room. I am looking for a one box solution. Three channel amps are not available in the Netherlands. Emotiva is not an option anymore.

Audyssey set the level trims of the DAES speakers 5db higher than the bed channels. I’ve double checked the levels with REW and they are level matched correctly with all the channels in the system.

Still, I have not bought a multichannel amp yet, because of the poor choices we have in the Netherlands. I can only choose between:

Rotel 1575 (can buy it for 1100 euros new)
Marantz 8077
Rotel 1585
Yamaha MX-A5000/5200

I am leaning towards the Marantz, off course because of the same make as my receiver. But I can’t find a lot of experiences of that machine online. The Rotel 1575 has bad reviews from users and others like it. To many subjective opinions.

My goal is to buy a model which can last for a long time to come. I am planning to buy a pre/pro somewhere in the near future. So at the moment the priority is to choose an amp which should be a set and forget purchase. I want a good amount of headroom and don’t want to worry about the volume knob. Also I am looking for a one box solution which can be perfectly paired with my speakers (150 RMS nominal, 600 peak I think). I am not looking for a “warm” sound, just a pure amplifier with a low noise floor and can fulfill my needs for movies and music (music in “Dolby Surround” mode always).

Outlaw and Monolith are unfortunately not available in The Netherlands. Importing those models are a headache because of customs and shipping costs for one.

I would appreciate some advise which multichannel amp is best for my setup.

The issue really comes down then to reliability and after sales service. This is difficult to prognosticate about. I would feel inclined, especially given your location to go with Rotel.

 

[Paul DS]

You are using two subwoofers which should be taking a significant load off of your receiver. There really isn't much reason for your receiver to clip.

 

[IMWhizzle]

You are using two subwoofers which should be taking a significant load off of your receiver. There really isn't much reason for your receiver to clip.

Better be safe than sorry. It depends on a lot of things as discussed above. I bought the RMB 1575 with 250watts per channel all channels driven. Unfortunately a black version is not available anymore. Bought it brand new sealed with 2 years warranty. Will install it tomorrow.

 

[TLS Guy]

You are using two subwoofers which should be taking a significant load off of your receiver. There really isn't much reason for your receiver to clip.

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.

 

[PENG]

In post #3 you mentioned the trim levels of the speakers which could be set according to you on -10db. Audyssey set the left and right speakers both on -4.5db.

Actually, to be clear, I said "If you have run Audyssey, I am curious what it did to your level settings. I suspect they will be close to -10 dB, due to the high speaker sensitivity for your 10 ft seating distance. "

"it" meaning Audyssey, not you. How "close" to -10 would obviously depend on how accurate Klipsch's specified sensitivity was.

I have always been cautions with Klipsh's specs in that regard. For example, for the RP-280F, they specified 98 dB/2.83 V and nom. 8 ohm compatible, but I suspected it was actually not. That's why in the calculations I posted in post#3, I dropped it to 92 dB/2.83 V just to exercise caution.

So if Audyssey set them to -4.5, if their claimed 98 dB was true, Audyssey would have in fact set the trim level very close to -10. I rest my case..

Regardless, can you tell us again why you still want to get a 7 channel amp when you most definitely do not need one, based on my calculations (if you check it with other calculators you can find online)? Don't get me wrong, it is good to have one for other reasons, but don't expect it to make a difference in "sound quality" fore you. My AVR is powerful enough for my HT room, but I have 3 power amps connected to it, but not for better sound quality.

You did mention ACH stereo, that could be a good reason, probably the only good reason related to sound quality (minimize chance of amp getting close to the clipping point).

 

[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.

Have you made any measurements that support you claim? Or I guess you have a different perception of "little".

I posted my measurements before that shows the difference in current draw was substantial, could be >2:1 going from "large" to XO 80 Hz, depending on the contents and whether EQ was used. The speakers used were full range towers, the characteristics of the speaker is obviously also a factor.