Volume: How high is safe

[Ali K]

I am running a Yam 1400 into KEF eggs. The speakers are rated at 100w whereas the amp is rated at 110 W per Channel RMS. what would be a safe volume? I was watching RotK today and the level of noise at -4 db was worrying me about my spealkers!!!!!

Although there was no distortion, the battle scenes had me wincing!!!!

 

[Daneel]

If your amp can't put out significantly more power than your speakers can handle you aren't going to damage speakers by overloading them.

However if you drive an amp to clipping (where it can't cope with what you are asking of it) that can damage your speakers. Typically it's an under-powered rather than over-powered amp that does damage. Distortion is a sign of clipping.

I'm guessing you will be fine up to 0 after which things may start to become unplesant for both you and your speakers.

 

[gIzzE]

If you set up your system with a level metre -0db on your amp should be 75db from the listening position.

You are more likely to do damge with a 110w amp than a 300w amp.

I use a cinepro power amp and when my processor is set to -0db I am actually at over 90db on the sound metre, which is over twice as loud, so I would tend to listen to my movies at -18 to -25 depending on the pressing/broadcast, but I have knocked the gains back on my amp about half way and now listen at around -7db, knowing -0db is about 20% over reference level.

So unless you have calibrated your system -4db means nothing and I am afraid no one can answer!

 

[Daneel]

I assumed his system was calibrated to reference level (105dB peaks on main speakers) at 0. Probably a bad assumption.

 

[Ali K]

Thank you all!!!!

I will definitely calibrate my amp to see what sort of sound pressure levels I am getting at various settings

I haven't actually got round to calibrating the amp properly. Although I've got a copy of Digital Video Essentials; the process of DYIng all the cables and installing the whole thing has taken too much time and I haven't got round to a proper calibration, YPAO auto-setup has been the only set-up I've done. Although the movie was very loud at -4 there was definitely no distortion.

Although the Yamaha RX-V1400 is only rated a 10 W per channel more than the RX-V750, it is a far more substantial piece of equipment (It is saying something that Yamaha quotes 750 as 7.1-Channel,700W Powerful Surround Sound (100W x 7) but the specs for the 1400 are High power 7-channel* discrete amplifier configuration (110W x 7RMS/FTC)) and I hope that -4db (the volume runs from -75 to +25) is not high enough to cause clippping.

 

[Ali K]

How real are the power ratings if the Yamaha 1400 only has 10 w more per channel than the 750 but weighs 7 pounds more and has THX Select whereas the 750 doesn't.

How far are 750's ratings are exaggerated? How close does the 1400 get to the claimed 7x110W?

 

[David_of_Surrey]

In a moment of madness I set my amp to -5db before the first attack in Master and Commander...all was fine (very very loud though) until the first shot was about to land on the deck..... the ship fired then.....next should be the shell landing on deck...but all went silent as the amp Sony STR-DB795 went into "Protect" mode and shut down. (it was fine after a reboot) actually -5dB with the 5005s is just plain SILLY... normally run it at -32 to -28 and that is VERY loud.

in my PA days we always used to recon that the rms rating of the speakers should be 1.5 to 2 times the amp rating to protect them in case of probs (dropped mike etc) so even today feel uneasy about having them equal.


http://www.jblpro.com/pages/general_faq.htm

gives usefull info

Dave

 

[gIzzE]

Problem with all the amps you guys are talking about abouve is they measure them one channel at a a time, where as a lot of power amps measure the ouput with all channels driven.
I know for a fact my old Parasound rated at 85w was a lot more controlled and louder than my Denon A1 intergrated rated at 140w. However the Denon sounded louder, what I mean is when they were both calibrated to output 75db at -0db the denon sounded a lot louder, but this is distortion not real volume. Add a 200 or 300w power amp to your system and play it at reference and it will seem even quieter, it won't be, but there is just more control there because of the extra headroom.

David I would say that if you have a speaker requiring 300 watts and you drive it with a 150watt amp you are far more likely to damage that speaker than if the figures were the other way round.

 

[Ali K]

Sorry about being uninformed

Would so something like the Yam 1400 be producing dangerous distortion at betwen -5 and 0 db some 25 db below its absolute maximum?

 

[Eddy Boy]

It depends. If at those volumes you can hear distortion turn down the volume.
It is better to have speakers that have a slightly lower power handling then your amp for the following reason.

It is not the amp distorting and you are left with the amps extra power for dynamics which you would not get if driving them at max.

When your speakers are higher then your amp and you turn up the volume it is the amp distorting beacuse it reached its limits for amplification. This distortion could damage your speakers.