Matching Receiver/Amplifier specs for given Speakers

[TLS Guy]

Thanks for the details. Don't think I am debating the need for power amp for my front stage. I agree with PENG on adding XPA-*.

Only thing I am still not 100% sure is if I can get away with lower powered XPA-5 considering I can amplify the center too for movies apart from FR/FL. Also seems 826v is rated for 150w RMS and 220w max power handling,so not sure how it will handle XPA-2. Will I need the power of XPA-2, for my stereo or can I manage with XPA-5 (use 3 channels).

Thanks

I think the XPA-5 should be fine. XPA-2 would be fine also, but won't power the other speakers.

 

[PENG]

Thanks for the details. Don't think I am debating the need for power amp for my front stage. I agree with PENG on adding XPA-*.

Only thing I am still not 100% sure is if I can get away with lower powered XPA-5 considering I can amplify the center too for movies apart from FR/FL. Also seems 826v is rated for 150w RMS and 220w max power handling,so not sure how it will handle XPA-2. Will I need the power of XPA-2, for my stereo or can I manage with XPA-5 (use 3 channels).

Thanks

Focal is one of those manufacturers who actually provide both RMS (technically wrong but generally accepted term) and "Maximum" power handling. Since the 826V is rated 200W maximum, so you are thinking that means the 200W XPA-3 or XPA-5 will be good enough right?

Now consider the following points.1)

1) The 826V is practically more like a 4 ohm nominal speaker.
2) Because of 1), the 220W maximum should be treated more like 400W.
3) We still don't know what Focal means by "Maximum" because they do not provide the "duration", my educated guess is that it can handle much higher instantaneous (very short peaks) currents, say double, without losing its composure.
4) Because of 3), the 826V could still benefit from amps that are rated higher than 220W such that if you ever turn the volume high enough and play contents that has very high dynamics to demand 400-500W of instantaneous peaks you have less chance to hear distortions.

The XPA-5 should be powerful enough but will offer less than 2dB over the Marantz. I preferred the XPA-2 over the -5 simply because it will get you 2 to 3 dB more reserve; and I don't believe in wasting the very capable amps in the SR7010 for the other 3 speakers that are much less demanding. The XPA-2 is also more future proof. I won't consider Emotiva amps for myself but they do offer excellent value. They good for people who want to have power that they need or don't need but have a <$1,000 budget.

Even TLSG is telling you that you may be fine without external amp if you keep the volume low. If you can provide your sitting distance and room dimensions, I can do some quick calculations to try and quantify the limits (volume) of the Marantz in your room.

 

[fmw]

Understand. Will your recommendation be XPA-2 still, even if the split between movies & 2ch-music is higher on the movies side and 826V cannot handle more than 220W?

Your ears can't handle 220 watts or even 1/2 of that.

 

[gankum]

If you can provide your sitting distance and room dimensions, I can do some quick calculations to try and quantify the limits (volume) of the Marantz in your room.

Thanks for the offer and your patience, appreciated.

So the total room dimension is close to 4000 cubic ft, but HT section of the room(that opens upto the bigger space) is only about 1000 cubic ft. The HT section is closed on both the side walls(12 ft apart). I sit about 9ft (edge of the HT section).

I did some calc myself online at http://www.hometheatrebasics.com/home-theatre-tools/spl-calculator , but interested in your analysis/numbers..

 

[PENG]

Thanks for the offer and your patience, appreciated.

So the total room dimension is close to 4000 cubic ft, but HT section of the room(that opens upto the bigger space) is only about 1000 cubic ft. The HT section is closed on both the side walls(12 ft apart). I sit about 9ft (edge of the HT section).

I did some calc myself online at http://www.hometheatrebasics.com/home-theatre-tools/spl-calculator , but interested in your analysis/numbers..

Can you provide (repeat if posted before) the LXWXH in your HT section? Not sure about edge of HT, what's the distance from your centre speaker?

 

[gankum]

9*12*9 . About 9ft from center

 

[TLS Guy]

Your ears can't handle 220 watts or even 1/2 of that.

That is only true if you are talking average power. A 220 watt amp with speakers of average sensitivity will run out of gas frequently and will not achieve concert level spl in the fortes.

To achieve the total concert experience requires a lot of power for truly effortless listening.

 

[TLS Guy]

Thanks for the offer and your patience, appreciated.

So the total room dimension is close to 4000 cubic ft, but HT section of the room(that opens upto the bigger space) is only about 1000 cubic ft. The HT section is closed on both the side walls(12 ft apart). I sit about 9ft (edge of the HT section).

I did some calc myself online at http://www.hometheatrebasics.com/home-theatre-tools/spl-calculator , but interested in your analysis/numbers..

I did not want to get into this late at night.

Since this is an HT rig, I don't think you have the optimal speakers. On your three way mains, the woofers are in reverse polarity to the mid and tweeters. The center for those speakers is not really matching at all, as the center is going to be out of phase with the mains over a good deal of the frequency spectrum. This is not a good thing at all.

This sort of thing happens a lot with three ways, because of the phase changes in the crossover region. Quite often you have to reverse phase of drivers to prevent nulls or suck outs at crossover.

I can guarantee that if you buy your proposed set up, you will be back here saying that Audyssey says there is an out of phase condition. You will insist that you have wired your speakers correctly, which you will have done. So you will be puzzled. We will tell you to override the out of phase message. However Audyssey will be correct and the three way mains are not blending correctly with the rest of the system.

If you are designing an HT speaker system, this is something you really should not allow to occur.

You might be better off looking at different speakers that will be more suitable in an HT environment and at the seem time be an easier load and not require the expense of an external amplifier.

In addition that metal some tweeter has a break up mode, and a horrendous one very close to the audible range. Personally I never like that. When it is that close I think it does have an adverse effect on the sound, not huge, but I don't like it.

 

[gankum]

The center for those speakers is not really matching at all, as the center is going to be out of phase with the mains over a good deal of the frequency spectrum.

I can guarantee that if you buy your proposed set up, you will be back here saying that Audyssey says there is an out of phase condition.
If you are designing an HT speaker system, this is something you really should not allow to occur.

You might be better off looking at different speakers that will be more suitable in an HT environment and at the seem time be an easier load and not require the expense of an external amplifier.

Hi TLS,
at this point, I already own these speakers after auditioning the Focal Chorus 700 series FR/FL/center at my local dealer..,as well as after discussing with Focal on the 800 series (about matching center channel , use case(Movies/Music mix etc). I've tested them with a Denon AVR too, at home and it sounds great to me...However as mentioned earlier, I am getting a Marantz(liked better for music) , HSU Sub , Focal Chorus Surrounds and External Power amp.

This forum has been really helpful and am sure you guys will help me out

 

[PENG]

9*12*9 . About 9ft from center

Thank you for the information, now let's summarize our assumptions for some rough calculations.

826 sensitivity: Manufacturer spec - 91 dB, S&V review found 88.5 dB so let's use 88.5 dB/2.83V/1M
Impedance of speakers: Manufacturer spec - 8 ohm nominal, 2.9 ohm min. S&V review: 3.56 min so let's assume 4 ohm nominal.
HT section dim: 9'X12'X9', so it is a small room but with large opening.
Positioning of speakers: within 2-4 ft from a wall

I did my own calculations but it would easier for you to use an online calculator such as this one:
http://myhometheater.homestead.com/splcalculator.html

So you need 1.7WPC for the L/R to achieve 85 dB average at your sitting position, or 170W to get 20 dB dynamic peaks without clipping the amp. Note that I doubled the calculated number based on 4 ohm impedance.

Any mid range D&M, Yamaha, NAD, Anthem AVR can do it for you without external amps. The assumptions are already conservative but if you wish to be even more conservative (ridiculously conservative), such as assuming 0 room gain, then you should add a 300WPC amp to power the 826V L/R and let the AVR do the rest.

 

[gankum]

Thank you, for the analysis. So given that the requirements fall within whats required at 4 ohms and dropped efficiency of the towers, am comfortable going with an XPA-5, given that it can output 300W RMS(continuous) at 4 ohms. Looks like the XPA-5's peak o/p might be higher than 300W, but I didn't see it published, only the RMS.
I understand its a compromise and I might be wasting some amps within the AVR, but given the movies are going to hit the center 80% of the time, I do want to get it through the power amp too. The AVR can power the Surround rears and any additional channels(7.1 in the future or atmos or whatever), with the LCR in the safer hands of Emotiva.

Appreciate the help,

 

[PENG]

but given the movies are going to hit the center 80% of the time, I do want to get it through the power amp too.

I doubt that, don't believe in hearsay. However, if you are mainly into movies, the XPA-5 does make sense.

 

[fmw]

That is only true if you are talking average power. A 220 watt amp with speakers of average sensitivity will run out of gas frequently and will not achieve concert level spl in the fortes.

To achieve the total concert experience requires a lot of power for truly effortless listening.

In my listening room with my speakers of average sensitivity (88db) at my normal listening levels, 18 watts per channel handles the peaks. How do I know? I've measured it. How may watts per channel do your average speakers dissipate on peaks?

I remember when the power wars started in the 1970's. Some of us wondered what the system was going to do with all that power. We were listening effortlessly to fortes with our 25 or 40 watt per channel amplifiers. If they were clipping then the clipping wasn't bad enough to be audible. My 60 watt per channel Harman Kardon Citation amplifier never came close to running out of gas. And that was in the pre-subwoofer era when 12" and 15" woofers were common in speaker systems.

 

[gankum]

However, if you are mainly into movies, the XPA-5 does make sense.

Glad we are on the same page,finally

 

[gankum]

In my listening room with my speakers of average sensitivity (88db) at my normal listening levels, 18 watts per channel handles the peaks. How do I know? I've measured it. How may watts per channel do your average speakers dissipate on peaks?
.

fmw, can I know how you measured it . Not challenging you here , asking how I can reproduce the test and measure it in my setup.

 

[fmw]

fmw, can I know how you measured it . Not challenging you here , asking how I can reproduce the test and measure it in my setup.

I've described it in detail elsewhere on the site. Basically it is a matter setting a test tone to the appropriate SPL and measuring the AC voltage and AC current at one of the speakers. Determining the appropriate SPL and the instructions for the measurements are in that post.

 

[gankum]

can you point me to that post ?

 

[PENG]

Glad we are on the same page,finally

Only because you are determined to get a 5 channel amp regardless right from start and zeroed in on Emo already. Well, you really can't go wrong with your final decision.

 

[PENG]

In my listening room with my speakers of average sensitivity (88db) at my normal listening levels, 18 watts per channel handles the peaks. How do I know? I've measured it. How may watts per channel do your average speakers dissipate on peaks?

I remember when the power wars started in the 1970's. Some of us wondered what the system was going to do with all that power. We were listening effortlessly to fortes with our 25 or 40 watt per channel amplifiers. If they were clipping then the clipping wasn't bad enough to be audible. My 60 watt per channel Harman Kardon Citation amplifier never came close to running out of gas. And that was in the pre-subwoofer era when 12" and 15" woofers were common in speaker systems.

I measured mine too, and to get 20 dB peak on top of 85 dB from sitting position I would need much more than 18W. Having said that, 18W will be fine for me too because in practice I only listen to 70 dB average when watching BR movies. I used 85 dB average +20 dB peak and more conservative assumptions in gankum's case assuming he wanted cinema experience in his HT section and not knowing much about his speakers placement that affects room gain.

 

[PENG]

given the movies are going to hit the center 80% of the time, I do want to get it through the power amp too.

I just measured the current to my centre and left front speakers playing the Hobbits opening dragon attack.

Left channel: average around 0.05-0.2 most of the time, 2.1A maximum peak.
Centre channel: average about the same as left channel, 1.6A maximum peak.

I realize this is just one movie but you get the idea.

So much for those hearsay about how the centre takes most heat. I guess Focal knows what they are doing, hence their matching centre is rated 150W maximum power handling, vs the front's 220W.