surround power vs LRC?

[efzauner]

On selecting surround, I have searched but cant find much info.. How much power is programmed to surrounds vs Fronts and Center?

I have seen numbers that the center handles up to 60pct of the front power.  What do the surrounds need? There should be some numbers on this from 5.1 program material. 

 

thanks

[Youthman]

Are you asking how many watts per channel the surrounds need vs the front LCR?  With most Klipsch speakers 100 watts / ch is fine.  200 watts / ch will give you more headroom and less chance for distortion.

[The History Kid]

Are you referring to average output? If so, the average output is likely a third to a quarter of what the main channels will deliver. Case in point, why some older PL receivers featured amplifiers with main sections at 150 RMS, while the surrounds were advertised at 50 or 60. Regardless, you shouldn't have a problem finding speakers to fit the bill, nor an amplifier with an issue of driving said surrounds.

[japosey]

Most current multi-channel amplifiers output equal power to all channels. Dolby Digital and DTS are designed with the intention that each discrete channel will/can play at equal volume, thus requiring equal amount of power. Dolby Pro Logic was not designed in that manner and multi-channel amplifiers prior to 1995-1997 always had rear channels that output 1/4 of the power of the LCR channels.

[moray james]

the centre channel accounts for between 60 - 65% of everything that you are listening to in a surround system and that's why it is the single most important speaker all the rest are for effects.

[mustang guy]

At any given time, a signal of the highest amplitude could be sent to any speaker in the system. It all depends on the way it was recorded and mastered. 

 

If you are buying speakers for a surround, you need to be sure the rears and the sub(s) can keep up with your expected max volume levels center and mains eg 110db. If you listen at low levels, any surround or sub will keep up with a set of mighty LCR's.  Raise the volume and the mains and center can pull away leaving the rears and sub(s) impossible to hear.

Edited March 14, 2016 by mustang guy

[derrickdj1]

Most people running a multichannel system have the speakers set to small.  This will lessen the amount of power needed for all the channels.  Also, all the channel are not requiring the max spl from the avr at the same time.  Most 100 watt avr's are plenty to power surround channels.  One thing for sure, in the RS/RP line, the smaller the surround, the more power needed.

[Quiet_Hollow]

What do the surrounds need?

For the minimum, see Page 18: https://www.jblpro.com/pub/cinema/cinedsgn.pdf

 

The old Dolby AC-3 literature suggests full "main channel" capability for the surround / satellites (naturally )....but as practical compromise I'd stick with surrounds that can maintain at least some semblance of timbre matching to the LC&R down to ~400 Hz (the 1st and 2nd harmonics of the male voice).

 

Using distance and delays to compensate for SPL requirements.

 

I've found that 5.1 concerts or specialty 5.1 tracks work the surrounds harder than actual movies, where they typically loaf along the majority of the time.

Edited March 14, 2016 by Quiet_Hollow

[mustang guy]

Most people running a multichannel system have the speakers set to small.  This will lessen the amount of power needed for all the channels.  Also, all the channel are not requiring the max spl from the avr at the same time.  Most 100 watt avr's are plenty to power surround channels.  One thing for sure, in the RS/RP line, the smaller the surround, the more power needed.

It occurs to me that if a speaker is set to small, then it's power handling potential is diminished since the voltage heavy frequencies are not being used. If a speaker is capable of 100 watts for frequencies between 50Hz-17KHz, and you don't send much below 80 Hz, and if the signals between 50Hz and 80Hz are 40% of the voltage that would be sent in full signal, then the speaker becomes a 60 watt speaker. Furthermore, if the speaker doesn't get that 50-80Hz signal if you send pink noise, it will not have as high of efficiency characteristics. Doesn't that really lower the max output on top of lowering power handling?

 

That stuff just popped into my head...

[TasDom]

From Anthem's FAQ:

 

Do the center and surrounds need less power than the fronts?

No definite answer, because:

Speakers vary. Some need more power than others.

Setups vary. For example, if level calibration is turned up by 3 dB in one channel, it'll use twice the power.

Source material varies. With action scenes, the center channel can be the hardest working aside from the sub. With multichannel pop music, the surrounds can have peak levels as high as the fronts, more so if the bass guitar and kick drum, often mixed into the fronts, are redirected via bass management.

Surround modes vary. Out of those which turn 5.1 input into 7.1 output, some make the surrounds louder, others make them quieter.

 

http://www.anthemav.com/support/faq.php

[efzauner]

 

What do the surrounds need?

For the minimum, see Page 18: https://www.jblpro.com/pub/cinema/cinedsgn.pdf

 

The old Dolby AC-3 literature suggests full "main channel" capability for the surround / satellites (naturally )....but as practical compromise I'd stick with surrounds that can maintain at least some semblance of timbre matching to the LC&R down to ~400 Hz (the 1st and 2nd harmonics of the male voice).

 

Using distance and delays to compensate for SPL requirements.

 

I've found that 5.1 concerts or specialty 5.1 tracks work the surrounds harder than actual movies, where they typically loaf along the majority of the time.

 

Good Info.. I think I had downloaded that manual a while back. 

HAHA.. yeah to quote that page:

"

F. Surround Requirements: As a general rule, the total ensemble of surround loudspeakers should be capable of producing as much acoustical power as a single screen channel. Today, the JBL 8340A surround loudspeaker is capable of producing total acoustical power output in the range of about 2 acoustical watts. Since a typical dual woofer JBL screen loudspeaker is capable of producing continuous acoustic power output of 28 watts, it is clear that 14 of the 8340A’s will be required for power matching. Typically, in a large house, 12 to 16 units will suffi ce. The careful designer should not specify less than this quantity. In smaller houses a similar quantity of 8330A’s may be specifi ed. "

 

apart from the smaller HTIB systems I don't see any HT systems that can output the same SPL on surrounds as for mains! 

[efzauner]

Thanks guys.. I guess I will have to wing it!
I have KLF-20s mains and dual KLF C7 centers placed below and above the TV, with a  AT screen for projector viewing.

Because of placement I have to use direct radiating surrounds placed in corners behind the listening position.

I found a two  Synergy SC-1s for sale at the same time, by different sellers, at reasonable prices. I will probably pick them up as they are local.  I am sure more powerful options will appear but these have an angled top/back so it will be an easy install aimed at the listening area. 

Love to find another pair of C7s but they are rare and pricey.   Someone is asking CDN$600 for one.. I paid $200 for the pair. was a very lucky find.  I also have lots of KG4 tweeters and Eminence Alpha 8 woofers I could build into a surround. But I am getting tired of building everything.

https://web.archive.org/web/20120622021245/http://www.klipsch.com/sc-1-center-speaker

[efzauner]

 

Most people running a multichannel system have the speakers set to small.  This will lessen the amount of power needed for all the channels.  Also, all the channel are not requiring the max spl from the avr at the same time.  Most 100 watt avr's are plenty to power surround channels.  One thing for sure, in the RS/RP line, the smaller the surround, the more power needed.

It occurs to me that if a speaker is set to small, then it's power handling potential is diminished since the voltage heavy frequencies are not being used. If a speaker is capable of 100 watts for frequencies between 50Hz-17KHz, and you don't send much below 80 Hz, and if the signals between 50Hz and 80Hz are 40% of the voltage that would be sent in full signal, then the speaker becomes a 60 watt speaker. Furthermore, if the speaker doesn't get that 50-80Hz signal if you send pink noise, it will not have as high of efficiency characteristics. Doesn't that really lower the max output on top of lowering power handling?

 

That stuff just popped into my head...

 

It really all depends on how the power handling is measured, and what the damage characteristics of the speaker is.  Typically woofers will break at low frequencies due to over excursion, and at higher frequencies due to thermal melt. Mids/tweets would be thermal.  So it depends what comes first! If during "normal" program material a speaker would be limited by low frequency woofer excursion, then yes, cutting out bass by setting to small would allow the speaker to  handle more power at the remaining frequencies and output higher SPL as handled by mid/high frequency drivers.  If however the power handling is limited by thermal, then removing the bass will not allow you to drive more power for higher SPL. 

[mustang guy]

 

 

Most people running a multichannel system have the speakers set to small.  This will lessen the amount of power needed for all the channels.  Also, all the channel are not requiring the max spl from the avr at the same time.  Most 100 watt avr's are plenty to power surround channels.  One thing for sure, in the RS/RP line, the smaller the surround, the more power needed.

It occurs to me that if a speaker is set to small, then it's power handling potential is diminished since the voltage heavy frequencies are not being used. If a speaker is capable of 100 watts for frequencies between 50Hz-17KHz, and you don't send much below 80 Hz, and if the signals between 50Hz and 80Hz are 40% of the voltage that would be sent in full signal, then the speaker becomes a 60 watt speaker. Furthermore, if the speaker doesn't get that 50-80Hz signal if you send pink noise, it will not have as high of efficiency characteristics. Doesn't that really lower the max output on top of lowering power handling?

 

That stuff just popped into my head...

 

It really all depends on how the power handling is measured, and what the damage characteristics of the speaker is.  Typically woofers will break at low frequencies due to over excursion, and at higher frequencies due to thermal melt. Mids/tweets would be thermal.  So it depends what comes first! If during "normal" program material a speaker would be limited by low frequency woofer excursion, then yes, cutting out bass by setting to small would allow the speaker to  handle more power at the remaining frequencies and output higher SPL as handled by mid/high frequency drivers.  If however the power handling is limited by thermal, then removing the bass will not allow you to drive more power for higher SPL. 

 

 

Unless you have and extremely capable tweeter (and midrange) then in all cases you mention, the RMS of the speaker is lessened by setting a HPF. The 1 meter efficiency may be higher or lower depending on the woofer efficiency. If the woofer is inefficient, then the efficiency will be higher than rated when a HPF is present. In that case, even though the speaker would have a lower wattage capability, the max SPL could be higher or lower. Nothing can be concluded from this.

 

My conclusions:  

• Setting a HPF on a speaker will lower it's power handling ability unless the tweeter (and mid) are very capable compared to the woofer. 
• In an AVR or preamp while speakers small, the wattage capability of the AVR or amp(s) is less than if the setting is large. 
• There will be less likelihood of clipping with HPF.