Will My AVR Be Sufficient To Drive These Speakers Loud?

M

mj30250

Audioholic Intern
Hello.

I plan to hook up some 4 ohm Emotiva speakers and I'm wondering if an X4500H can safely and properly push them at or near reference levels without the need for an external amp. Fortunately, they are fairly sensitive speakers, so I'm thinking I'll be fine, but I'm wondering if anyone has a similar setup and could offer their thoughts. This would be easier if I could find some impedance charts for the speakers, but they've been hard to come by.

C2+ center, 92 dB sensitivity
T2+ towers, 91 dB sensitivity

I also have 2x Polk FXi A4 surrounds going through the AVR as well as 2x Hsu VT3-MK5 subs for LFE duties. The subs will be in the mix nearly all of the time, so they will take some strain off of the AVR.

MLP is roughly 8' from the fronts. The room is in a finished basement (fully carpeted) and would be on the smaller side if not for an opening on one side. The ceiling is standard height and made up of mostly acoustical tiles. I've attached an old sketch for a (very) rough idea of what the area looks like. I'm trying to avoid constantly second guessing whether I should have shelled out for an external amp. If I did I'd likely have my sites set on a Monolith 3x200 - although even at that I'm not certain the nearby circuit would be happy with it as the circuit is under a 15amp breaker and it already powers one of the big subs as well as the AVR, TV, and all sources. Usage is 65% HT, 35% music. Most listening will be done at "reasonable" levels, however, there will be the occasional sessions where I will push things to near reference for the length of a movie or an album or two. Any insights would be appreciated. Thanks!
 

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L

Leemix

Audioholic Chief
You can try one of the dB calculators thats linked many places. If 4ohm 91dB speakers arent that easy to drive but its not a big space and you sit fairly close. (For the sub the space is bigger to fill)
Calculations aside, when increasing the volume hear if it starts to sound harsh or stressed, if it does turn it down a little.
Play ata volume comfortable to you and all those listening, reference doesnt really mean anything because things arent recorded to a reference to begin with on cd/blu-ray/streaming and so on. Reference level on the AVR with 2ch music will probably be far louder than 85dB with very short peaks to 105dB since they make them as loud as possible.(unfortunatly)


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P

PENG

Audioholic Slumlord
As mentioned, you should use a calculator that will give you the answer. It depends not only on sensitivity. Impedance and distance are also the main factors.
 
M

mj30250

Audioholic Intern
In terms of calculating the true room size, how should I account for the fact that on one side the wall opens to a large area? As far as the front speakers are concerned, all drivers will be pointed at the back wall. If the room were sealed I'd be looking at about 1600 cubic feet of space, but obviously it isn't.
 
L

Leemix

Audioholic Chief
In terms of calculating the true room size, how should I account for the fact that on one side the wall opens to a large area? As far as the front speakers are concerned, all drivers will be pointed at the back wall. If the room were sealed I'd be looking at about 1600 cubic feet of space, but obviously it isn't.
Thats mainly the subs problem.


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M

mj30250

Audioholic Intern
That's what I figured - no issues on the sub front.

So when calculating power requirements, most calculators are set for 8 ohm impedance and don't let you adjust it, so would I simply reduce sensitivity by 3 dB for each speaker before plugging in the numbers?
 
L

Leemix

Audioholic Chief
That's what I figured - no issues on the sub front.

So when calculating power requirements, most calculators are set for 8 ohm impedance and don't let you adjust it, so would I simply reduce sensitivity by 3 dB for each speaker before plugging in the numbers?
Should be. You can play around with it a bit also to see how different variables affect each other.


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M

mj30250

Audioholic Intern
Ok, probably a dumb question - but for amplifier power, the receiver is rated at 125 watts at 8 ohms, two channels driven, and 165 watts at 6 ohms, 2 channels driven. When accounting for multi-channel (FRC and surrounds) what number should I enter for power? I also don't know what the X4500H would measure in terms of output at 4 ohms as nothing seems to be published.
 
L

Leemix

Audioholic Chief
Ok, probably a dumb question - but for amplifier power, the receiver is rated at 125 watts at 8 ohms, two channels driven, and 165 watts at 6 ohms, 2 channels driven. When accounting for multi-channel (FRC and surrounds) what number should I enter for power? I also don't know what the X4500H would measure in terms of output at 4 ohms as nothing seems to be published.
Thats a good question and unless someone has measured it we just dont know. Probably between 50w and 75w depending on how many channels active.
Most dont publish 4ohm numbers because that can cause heat problems with modern AVRs. Which means you have to watch out when running loud. Having speakers set to small and let the sub do most of the work will help.
Unelss you use all channel stereo mode you are very unlikly to have all speakers running full out at the same time though.


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M

mj30250

Audioholic Intern
I stayed conservative and punched in 50 watts for amplifier power, went with 88 dB for speaker sensitivity (91 dB for the towers less 3 dB to account for 4 ohm) and came up with 105 dB SPL at MLP. That seems fairly reasonable to me. When you factor in an 80Hz crossover with the subs doing the heavy lifting up to that point - I'm thinking I wouldn't be missing out on much if anything in staying with the AVR alone. Agreed ? Or am I missing anything critical? Thanks again.
 
ryanosaur

ryanosaur

Audioholic Spartan
It’s important to keep in mind that most multi channel usage does not run the same program through all speakers simultaneously. With the exception of multichannel stereo, that is.
It is strongly recommended to not use multichannel stereo for loud listening as that is likely the fastest way to blow something.
Most multichannel up mixers will parse elements of the original signal in a manner that is less demanding of the Amp Stage (at least as I understand it).
I prefer my 2-channel as just that and never engage Multi Channel Stereo. Some like MCS for parties where you want background music, so all speakers are working, but only lightly taxing the amps as volume is kept reasonable for conversation to be held without yelling. ;)
As always, YMMV, and your preferences are your own.
Regardless, I would expect your system as described to get pretty close to reference level for movies, including dynamic peaks, at your stated LP. My rough math looks like you wouldn’t need more than about 64w to reach those peak levels.
But the warning again: continued output at that level will likely damage your gear... and your hearing! :)
 
L

Leemix

Audioholic Chief
I stayed conservative and punched in 50 watts for amplifier power, went with 88 dB for speaker sensitivity (91 dB for the towers less 3 dB to account for 4 ohm) and came up with 105 dB SPL at MLP. That seems fairly reasonable to me. When you factor in an 80Hz crossover with the subs doing the heavy lifting up to that point - I'm thinking I wouldn't be missing out on much if anything in staying with the AVR alone. Agreed ? Or am I missing anything critical? Thanks again.
Looks like you are good with just the AVR yes, keep an eye on the temperature when running loud so you know if its something you need to watch.


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M

mj30250

Audioholic Intern
Regarding multi-channel stereo - no, that's not something I do. For stereo I much prefer 2.2. Multi-channel is reserved for the appropriate TV shows / movies / games.

Thanks, everyone! I definitely have some peace of mind now. I read some reviews of the T2+ towers specifically where it was mentioned that a hefty external amp is "required!". I didn't think that sounded quite right as first of all, the reviewers never attempted to run them off of an AVR, and secondly, it's a super generic statement that doesn't take into account listening position, room size, etc, but it still left me second guessing things. I look forward to taking everything for a spin soon.
 
Gmoney

Gmoney

Audioholic Samurai
Regarding multi-channel stereo - no, that's not something I do. For stereo I much prefer 2.2. Multi-channel is reserved for the appropriate TV shows / movies / games.

Thanks, everyone! I definitely have some peace of mind now. I read some reviews of the T2+ towers specifically where it was mentioned that a hefty external amp is "required!". I didn't think that sounded quite right as first of all, the reviewers never attempted to run them off of an AVR, and secondly, it's a super generic statement that doesn't take into account listening position, room size, etc, but it still left me second guessing things. I look forward to taking everything for a spin soon.
Yeah some forums love saying, oh but if you add a 200 watt amp your speakers will open up. :rolleyes:. If you read post say in a Emotiva forum you'll find a lot of BS. Why? cause it's a Emotiva forum and they sell amps! Plus lots of employees hangout in that forum. Your Denon is More than capable of making your ears bleed if you choose to.
 
M

mj30250

Audioholic Intern
Yes, that was a thought I had as well. It also makes we wonder if the speakers truly dip down into 4 ohm territory much if at all, or if Emotiva is stretching out the rating a bit to sell more amps. I'd really like to see some measurements for the T2+ towers, but I'm not sure they exist in a public forum (yet).
 
M

mj30250

Audioholic Intern
Not yet but the order is in. I'm currently running Polk RTi 10s and a CSI A6 center. I very much like the C2+ center and I went with the T2+ speakers so that the front stage would be reasonably matched. I also looked at the JBL 590s, but they're just a bit too bulky for my space.
 
P

PENG

Audioholic Slumlord
Yes, that was a thought I had as well. It also makes we wonder if the speakers truly dip down into 4 ohm territory much if at all, or if Emotiva is stretching out the rating a bit to sell more amps. I'd really like to see some measurements for the T2+ towers, but I'm not sure they exist in a public forum (yet).
From the measurements I could see that they did dip below 4 Ohms at some points. Using 80 Hz crossover should help, again, the users should use an online calculator to fine the limitations. Or just get a 500 W rated power amp and have no worry except don't go crazy on the volume dial.:D
 
L

Leemix

Audioholic Chief
The new speakers are quite small and will have limitations. Might not be an upgrade compared to what you have but you can try the new center and the old speakers also, its not that bad to have a different center unless you play a lot of multichannel music.


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