seting speakers and sub levels...


Active Member
Do i really have to set my amp to 0db to calibrate to 75 bd (or whatever it its) ?

I have set mine at a lower level so i dont get the neighbours coming round ! But my thinking is , if there all set to the same level, then it doesnt really matter what level your volume on the amp is set to.

Am i correct ?

Also sub woofers, Because the needle is waving around , do i set the sub to the highest the needle goes to when playing the test tone ?



When you have set all speakers to 75db at 0 it does'nt matter what volume you play at, all speakers will play equally loud.
But at 0 is reference level, or in THX that is actually 85db, but that is way to loud.
The needle should be pretty steady when set to C-weighting and slow response. Be awere thet a spl meter measures the lower frequencies to low. So the corrrect level for the sub will be a couple of db below 75db.
And another thing, the internal test tones of your surrond prossesor is probably wrong ( my Denon AVC A11SR is almoast 20 db to high),so use a test disk to set the reference level. I use the Ultimate DVD Platinum and a radio shack SPL meter.
Hope this covers it.
regards Hans


Active Member
Thanks for the reply magking, I have set my speaker levels when the amp is set to about -25 , because if it set it to 0db i would get the neighbours coming round.

Does it make any difference that i set it at a lower level than 0db ?

Surely if all speakers are at the same level, it shouldnt matter what the volume level is set at when calibrating ? Am i wrong ?



No it does'nt matter what level you set them up at, but you'll not know the reference level.
It'll only take you about 5mins to set the reference level to 75db, i'm sure the neighbours could live with that.
You don't have to use your system at that level, but that will be the reference level.
I have my AVC A11SR at -10 db at 75db, because i have the fronts at -8db and at 0 i would have to set them to -18db which is not possible, max -12db.
About the sub setup, yes set it to max 75db


Active Member
Thanks magking, ive just set the speakers at 0db, it wasnt as loud as i though, my normal listening volume is -30.

The sub i have set at 75bd also, the needle peaks at around 77db.

Thanks for the advice


Standard Member
The Digital version of the Radioshack SPL can measure the average level so is good at measuring a sub's level, however the Analogue version is rumoured to be more accurate :rolleyes:

For the sub's level I now prefer to use my ears, far better results as long as the sub is positioned properly IMO.

Good luck at trying to listen to a movie with the speakers set to output 85Db, the loudest setting I listen to a movie at equates to 76Db on a SPL :)

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