Amp to drive McIntosh LCR 80s for HT system Left F, Center & Right F.

D

Danno51

Audiophyte
Looking for advice on what amplifier to purchase to to properly drive my 3 McIntosh LCR 80s

Speaker sound level is lower than I would like due to the relatively low sensitivity of 81dB that the LCR80s have. I am able to drive them with my Carver (125W) or my Anthem (140W), but I'd like a bit more sound power out of them.

I'm seeking advice on what Amp to choose that would provide adequate sound levels at a distance between 8 and 14 feet, has a neutral to slightly warm sound and have the build quality that should allow me to use this amp for many years to come.

Below are two amplifier options that I believe will help me with my sound level issue, but I I'm seeking additional opinions. If another brand/model may pair better with the McIntosh LCR80s I'd be happy to hear about them as well.
  • Anthem 525 (ii) (225W/channel)
  • Parasound Halo A51 (250W/channel).

Note: I am fully aware that there are many speakers on the market with a higher sensitivity available, but the home theater that I am building is in a common space and I have some clear spousal design inputs that required the following:
  • Spend what you want, but keep the room uncluttered.
  • No floor or stand speakers
  • Speakers must either be in wall or on wall.
  • Speakers also must not be giant or ugly.
We chose the LCR80s because they were the rare speaker that met all the constraints, yet still sound great (to me). Unfortunately they come with cost of being significantly more power hungry than a higher sensitivity speaker.

Current System: 7.2.4 system
Anthem MRX 1140 (140W/5 channels; 65W/6 channels)
McIntosh LCR80s (Front, Center, Left) 75-300W, 81dB sensitivity
Energy RC-6Cst & RC6W in wall speakers (150W) - Rear and back
Klipsch CDT 3800 cii (100-200W) - Height Speakers (likely will re-matrix 4 of the 140W channels from the Anthem MRX 1140)
Sunfire HRS12 (1000W) - Subwoofer x2

Thank you in advance,

Dan
 
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TLS Guy

TLS Guy

Seriously, I have no life.
Looking for advice on what amplifier to purchase to to properly drive my 3 McIntosh LCR 80s

Speaker sound level is lower than I would like due to the relatively low sensitivity of 81dB that the LCR80s have. I am able to drive them with my Carver (125W) or my Anthem (140W), but I'd like a bit more sound power out of them.

I'm seeking advice on what Amp to choose that would provide adequate sound levels at a distance between 8 and 14 feet, has a neutral to slightly warm sound and have the build quality that should allow me to use this amp for many years to come.

Below are two amplifier options that I believe will help me with my sound level issue, but I I'm seeking additional opinions. If another brand/model may pair better with the McIntosh LCR80s I'd be happy to hear about them as well.
  • Anthem 525 (ii) (225W/channel)
  • Parasound Halo A51 (250W/channel).

Note: I am fully aware that there are many speakers on the market with a higher sensitivity available, but the home theater that I am building is in a common space and I have some clear spousal design inputs that required the following:
  • Spend what you want, but keep the room uncluttered.
  • No floor or stand speakers
  • Speakers must either be in wall or on wall.
  • Speakers also must not be giant or ugly.
We chose the LCR80s because they were the rare speaker that met all the constraints, yet still sound great (to me). Unfortunately they come with cost of being significantly more power hungry than a higher sensitivity speaker.

Current System: 7.2.4 system
Anthem MRX 1140 (140W/5 channels; 65W/6 channels)
McIntosh LCR80s (Front, Center, Left) 75-300W, 81dB sensitivity
Energy RC-6Cst & RC6W in wall speakers (150W) - Rear and back
Klipsch CDT 3800 cii (100-200W) - Height Speakers (likely will re-matrix 4 of the 140W channels from the Anthem MRX 1140)
Sunfire HRS12 (1000W) - Subwoofer x2

Thank you in advance,

Dan
As you know the 81 db sensitivity is a problem. Their max power handling is 300 watts, and the speakers are fused, so if you exceed 300 watts the fuse will blow.

The db log scale is against you. So if the speakers were 91 db sensitivity, the speakers would sound twice as loud.

So to double the loudness of your 140 watt Anthem would require a 1,400 watt amp to each LCR speaker. Since the max power is 300 watt a 300 watt amp will only get you an extra 3db increase in level. You will have to decide if this is worth the capital outlay. In that power range you might want to consider a pro-amp like QSC. They have very high reliability. Of course Mac amps are high reliability. I think they make a 300 watt amp to match those speakers.

So what ever you do you are up against domestic constraints. Good in wall speakers are far and few between. But speakers of more usual sensitivity of the 89 to 91 db range, would do what you want without changing the amps. To be honest, I have never encountered a speaker with that low a sensitivity before. But you have to face facts that those speakers are clearly not high spl. speakers. In addition to the low sensitivity, and because of it, I suspect the speakers will suffer dynamic thermal compression as you increase power, so their is a good chance you would not even realize the 3db increase in spl.

So you have some decisions to make.
 
Verdinut

Verdinut

Audioholic Ninja
It is unfortunate that those McIntosh have a very low sensitivity. Depending on your planned listening distance from them. it is quite possible that you would never be able to obtain the kind of SPL and dynamic range that you are aiming for and risk blowing their fuses.

IMO, the best solution would be to return them if you can or sell them, then replace them with other speakers with a sensitivity very close to 90 dB. There are several good ones which have such sensitivity and can handle up to 200 to 300 watts as well.

TLS Guy's suggestion of pro audio QSC amps is a wise option. As a matter of fact, in my HT system I am using 4 QSC amps. These DCA series amps are used in Cineplex Theaters across North America. They are reliable, have excellent specs and you can't blow them:
 
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D

Danno51

Audiophyte
Thank you so much for the feedback. Your collective insights confirm much of what I was concerned about. I have some thinking to do on this. I can still return the speakers for another 2 weeks or so and very well may. I'll report back my decision.

Thanks again for taking the time to provide me with your guidance
 
TLS Guy

TLS Guy

Seriously, I have no life.
Thank you so much for the feedback. Your collective insights confirm much of what I was concerned about. I have some thinking to do on this. I can still return the speakers for another 2 weeks or so and very well may. I'll report back my decision.

Thanks again for taking the time to provide me with your guidance
You are welcome. I would return those speakers, they are not going to provide the results you are obviously looking for.

I did contact Sigberg audio. They are a new company in Norway that sell in the states. They are devoted exclusively to active speakers with DSP. As someone who has designed and built speakers for over half a century, I am certain their design approach is correct. They are compact speakers with high spl. that measure superbly. They make subs designed to precisely crossover to them. They are small speakers, but more powerful than most large ones.

I wrote to the owner this afternoon to see if the active crossover could be tweaked for in wall application. This is much easier to do with an active design than a passive design where optimum results are not really possible. My center is an active through wall, and is an absolutely superb center.

Speakers design is in one of its biggest states of flux for years, and on the threshold of quantum leaps in performance.
 
TLS Guy

TLS Guy

Seriously, I have no life.
You are welcome. I would return those speakers, they are not going to provide the results you are obviously looking for.

I did contact Sigberg audio. They are a new company in Norway that sell in the states. They are devoted exclusively to active speakers with DSP. As someone who has designed and built speakers for over half a century, I am certain their design approach is correct. They are compact speakers with high spl. that measure superbly. They make subs designed to precisely crossover to them. They are small speakers, but more powerful than most large ones.

I wrote to the owner this afternoon to see if the active crossover could be tweaked for in wall application. This is much easier to do with an active design than a passive design where optimum results are not really possible. My center is an active through wall, and is an absolutely superb center.

Speakers design is in one of its biggest states of flux for years, and on the threshold of quantum leaps in performance.
I have heard back from Sigberg Audio. They can easily alter what is known as Baffle Step Compensation of these speakers, as I suspected, since they are active.

However there is concern about ventilation. These speakers are already able to be used on wall. So I need to know the details of how your current speakers are installed and if they are not on wall, then the precise details and dimensions of your wall space at the speaker locations.

The baffle step compensation is the frequency at which a speaker transitions, from being a half space, to a full space radiator, and is related to the width of the front baffle. Obviously a totally in wall speaker needs no baffle step compensation as it can only be a half space radiator. However, I and others have found, that if a speaker protrudes at all from the wall, in other words is what we call a through wall installation, then some degree of BSC is required.

In view if your desires this is really good news for you. We certainly have the possibility we can design a neat, elegant killer system in accordance with your wife's restrictions. It will be far from the cheap solution but not through the roof either, but commensurate with the excellent high end system it would be.

So pictures, pictures, pictures!

I am posting a picture of the front of my system and the center speaker is through wall, but that speakers is a transmission line and significantly larger then the Sigberg sealed designs. I just have a penchant for designing TL speakers.





One thing that speaker does have in common with the Sigberg speaker is the use of coaxial drivers.
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
If I had McIntosh speakers, I would have no choice but to get McIntosh amps. :D

Just like if I had Bryston speakers, I would have no choice but to get Bryston amps. :D

I'm a robot. That's how I'm programmed. :eek: :D
 
P

PENG

Audioholic Slumlord
Looking for advice on what amplifier to purchase to to properly drive my 3 McIntosh LCR 80s

Speaker sound level is lower than I would like due to the relatively low sensitivity of 81dB that the LCR80s have. I am able to drive them with my Carver (125W) or my Anthem (140W), but I'd like a bit more sound power out of them.

I'm seeking advice on what Amp to choose that would provide adequate sound levels at a distance between 8 and 14 feet, has a neutral to slightly warm sound and have the build quality that should allow me to use this amp for many years to come.

Below are two amplifier options that I believe will help me with my sound level issue, but I I'm seeking additional opinions. If another brand/model may pair better with the McIntosh LCR80s I'd be happy to hear about them as well.
  • Anthem 525 (ii) (225W/channel)
  • Parasound Halo A51 (250W/channel).

Note: I am fully aware that there are many speakers on the market with a higher sensitivity available, but the home theater that I am building is in a common space and I have some clear spousal design inputs that required the following:
  • Spend what you want, but keep the room uncluttered.
  • No floor or stand speakers
  • Speakers must either be in wall or on wall.
  • Speakers also must not be giant or ugly.
We chose the LCR80s because they were the rare speaker that met all the constraints, yet still sound great (to me). Unfortunately they come with cost of being significantly more power hungry than a higher sensitivity speaker.

Current System: 7.2.4 system
Anthem MRX 1140 (140W/5 channels; 65W/6 channels)
McIntosh LCR80s (Front, Center, Left) 75-300W, 81dB sensitivity
Energy RC-6Cst & RC6W in wall speakers (150W) - Rear and back
Klipsch CDT 3800 cii (100-200W) - Height Speakers (likely will re-matrix 4 of the 140W channels from the Anthem MRX 1140)
Sunfire HRS12 (1000W) - Subwoofer x2

Thank you in advance,

Dan
According to the manual, the LCR80 use PTC fuses:

The Network also utilizes self resetting high current PTC Fuses to provide an extra measure of protection.
and also:

• Loudspeaker Protection The LCR80’s built-in speaker protection incorporates three automatic resetting solid-state devices in the crossover network. One protects the tweeter, one for the midrange drivers and one for the woofers.
So they won't blow easily as they will limit the current at some points, and automatically reset to the normal state.

If you really like those speakers but the MRX1140 cannot drive them loud enough then you can try a 600 W rated amp and see if the extra 6 dB can do the trick.

Will you dealer loan you such an amp, such as the Anthem STR, or the P5? The MCA525 and Parasound A21+ cannot make much unless you bridge them.

Based on one S&V measurements, I can't see how the LCR80 can sound good if neutrality is the reference so I agree with others that you should return them but again if that's what you like then try a more powerful amp.

Dreaming the Not-Impossible Dream HT Labs Measures | Sound & Vision (soundandvision.com)

Note that McIntosh claimed "The Crossover Network used in the LCR80 Loudspeaker System is designed to ensure an even frequency response over the entire audible range. "

The FR curve (green) below showed that it was anything but even!! That's for anechoic so in room could be better or worse as it depends.

1661693829194.png


This graph shows the quasi-anechoic (employing close miking of all woofers) frequency response of the XR100 L/R (purple trace), LCR80 center channel (green trace), and XR50 surround (red trace). All passive loudspeakers were measured with grills at a distance of 1 meter with a 2.83-volt input and scaled for display purposes.
 
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TLS Guy

TLS Guy

Seriously, I have no life.
According to the manual, the LCR80 use PTC fuses:



So they won't blow easily as they will limit the current at some points.

If you really like those speakers but the MRX1140 cannot drive them loud enough then you can try a 600 W rated amp and see if the extra 6 dB can do the trick.

Will you dealer loan you such an amp, such as the Anthem STR, or the P5?

Based on one S&V measurements, I can't see how the LCR80 can sound good if neutrality is the reference so I agree with others that you should return them but again if that's what you like then try a more powerful amp.

Dreaming the Not-Impossible Dream HT Labs Measures | Sound & Vision (soundandvision.com)

Note that McIntosh claimed "The Crossover Network used in the LCR80 Loudspeaker System is designed to ensure an even frequency response over the entire audible range. "

The FR curve (green) below showed that it was anything but even!! That's for anechoic so in room could be better or worse as it depends.

View attachment 57557

This graph shows the quasi-anechoic (employing close miking of all woofers) frequency response of the XR100 L/R (purple trace), LCR80 center channel (green trace), and XR50 surround (red trace). All passive loudspeakers were measured with grills at a distance of 1 meter with a 2.83-volt input and scaled for display purposes.
I can tell you, that I would never consider using speakers with 81 db sensitivity no matter who made them. There are just too many issues. That extra power to drive them will all be excess heat in the VC, with thermal compression and a increased chance of speaker failure. For me that would be an outright rejection, and back to the drawing board. That is a big enough mark against it to label it a BAD design.
 
P

PENG

Audioholic Slumlord
I can tell you, that I would never consider using speakers with 81 db sensitivity no matter who made them. There are just too many issues. That extra power to drive them will all be excess heat in the VC, with thermal compression and a increased chance of speaker failure. For me that would be an outright rejection, and back to the drawing board. That is a big enough mark against it to label it a BAD design.
81 dB is indeed ridiculously low, 85 dB would be my limit. Do you think may be they are acoustic suspection design? Even then, it shouldn't be hard to achieve 84 dB. MCintosh should know better.
 
TLS Guy

TLS Guy

Seriously, I have no life.
81 dB is indeed ridiculously low, 85 dB would be my limit. Do you think may be they are acoustic suspection design? Even then, it shouldn't be hard to achieve 84 dB. MCintosh should know better.
I really don't know or care. I have heard MCintosh speakers over the years and they were all bad. I mean bad.
 
lovinthehd

lovinthehd

Audioholic Jedi
I can tell you, that I would never consider using speakers with 81 db sensitivity no matter who made them. There are just too many issues. That extra power to drive them will all be excess heat in the VC, with thermal compression and a increased chance of speaker failure. For me that would be an outright rejection, and back to the drawing board. That is a big enough mark against it to label it a BAD design.
How big a difference in actual speaker efficiency does the low sensitivity translate to, though? By my calculations using this it's still relatively small percentage wise (altho a doubling from 81 to 84 sensitivity). It seems that it is a relatively small difference as far as heat management would go....but not sure how that works on the speaker coil....
 
TLS Guy

TLS Guy

Seriously, I have no life.
How big a difference in actual speaker efficiency does the low sensitivity translate to, though? By my calculations using this it's still relatively small percentage wise (altho a doubling from 81 to 84 sensitivity). It seems that it is a relatively small difference as far as heat management would go....but not sure how that works on the speaker coil....
First off, 84 db is not spectacular and well to the bottom of the range. Every 3 db increase in sensitivity halves the power required for the same spl.

More usual sensitivities are in the 88 to 90 db range. Now the heating effect goes up by the square of the current in the VC. This what engineers refer to as the i squared R loss. So this is a significant issue.
 
TLS Guy

TLS Guy

Seriously, I have no life.
I really don't know or care. I have heard MCintosh speakers over the years and they were all bad. I mean bad.
And those FRs that PENG posted are what I am talking about. They would be a disgrace for a low end budget manufacturer.
 
TLS Guy

TLS Guy

Seriously, I have no life.
Thank you so much for the feedback. Your collective insights confirm much of what I was concerned about. I have some thinking to do on this. I can still return the speakers for another 2 weeks or so and very well may. I'll report back my decision.

Thanks again for taking the time to provide me with your guidance
I have had significant correspondence with Sigberg audio. The good news is that they are anxious to work with you in this endeavor. They are really waring up to this whole concept. This was raised by another member here in another thread.

I really think this is a golden opportunity for you. I can tell with my communications that they are a company driven to excellence and ethical individuals.

They have asked that if this is a go for you, that I be involved in the project, especially how to make an elegant project in its totality. I have agreed that if all parties are willing, I will certainly use my experience to the fullest to make this project a success.

Your problem is not unique, but it is one that lacks really excellent solutions. I really do believe that what Sigberg bring to the table, really has an excellent chance of moving the goal posts. I would say that we appear to be very much aligned in our approach over fundamental issues.
 
witchdoctor

witchdoctor

Full Audioholic
If I had McIntosh speakers, I would have no choice but to get McIntosh amps. :D

Just like if I had Bryston speakers, I would have no choice but to get Bryston amps. :D

I'm a robot. That's how I'm programmed. :eek: :D
I was thinking of one of your posts, I just got a Paradigm preamp for my paradigm active speakers. It includes ARC room correction and I now have a dedicated Paradigm two channel setup. I just ordered it and it was about 40% discount on Paradigms website.
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
I was thinking of one of your posts, I just got a Paradigm preamp for my paradigm active speakers. It includes ARC room correction and I now have a dedicated Paradigm two channel setup. I just ordered it and it was about 40% discount on Paradigms website.
Very OCD. :D

If I were loaded, I'd get those Focal Grande Utopia and that $20K Focal AVR. :D
 
Replicant 7

Replicant 7

Audioholic Samurai
Very OCD. :D

If I were loaded, I'd get those Focal Grande Utopia and that $20K Focal AVR. :D
But You are loaded! Your living the dream. Gotta home mortgage, properties on the west coast mortgage, you have two BS's. your living the American dream I tell you! financed lifestyle. You gotta show up at work .

Or ole wifey going to find herself a new milk Cow to pay them mortgages. Plus she gonna sell off all your gear at low low special holiday sale!! Yep Andrew You're knee deep in the American dream!!!:D slave to the banks!! LMAO
 
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