Sound Level on Home Theater

Discussion in 'Archived Threads 2001-2004' started by Eric Taylor, Mar 17, 2002.

  1. Eric Taylor

    Eric Taylor Agent

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    Can someone please explain to me in laymans terms how to understand what the Dolby Reference Level for my Home Theater should be. I have a RCA Home Theater in a Box system and the volume goes from 00db up to 120db. I usually have it set around the 55db to 65db range when watching DVD's and around 25 to 30db's when watching tv.

    I recently bought a Rat Shack SPL Meter, but I don't have a calibration dvd as of yet. I am using the tones on my receiver to set it up for right now. What should I have my master volume set too to set the speakers up? I used 75db but have read all kinds of different settings and cannot figure out where to have the master volume set so I can get my speakers to 75db on the meter. Any help on this would be very very very appreciated. Thanks guys.
     
  2. Mark Hobbs

    Mark Hobbs Stunt Coordinator

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    Once you get a calibration disk, you can calibrate so that "reference" level is whatever you want it to be on your receiver. The AVIA disk is set up so that using their test tones, you put your receiver's volume on what you want "reference" to be, then adjust each speaker until the output from the AVIA disk equals 85db on your SPL meter.

    I understand the VE disk uses 75db. Either way, once you are finished, your receiver should be at reference volume when it is turned to that setting. I use 0 as ref, since my receiver goes from -60 to +18. I actually listen at about -20. In your case, you might want to use 75 or 85. It doesn't matter, just remember that whatever you use is "reference" level for you.

    I'm not sure how you would set reference level using your receiver's test tones. I would suggest using the AVIA disk, since receiver tones can be incorrect.
     
  3. Eric Taylor

    Eric Taylor Agent

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    Thanks Mark, this helped out quite a bit. I want to get a calibration disc but just haven't had the money too and there is no place close to here that carries them. I tried to just rent one but no one carries them for rental either. I don't have a credit card either so ordering online is sorta out too. But I will figure out a way sooner or later I am for sure to get one.
     
  4. Dustin B

    Dustin B Producer

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    You will be used to well under Avia's 85dB reference level right now. An RCA HTB is not going to be capable of full reference level. Reference level is LOUD. Most people would consider 10-15dB under reference to be plenty loud enough. Especially with a HTB (the speakers and especially the subs in HTBs just aren't capable of high spl levels without lots of distortion). However, getting a spl meter and a calibration disk so you can level match your speakers at 15dB under reference will still greatly benefit you.
     
  5. Mark Hobbs

    Mark Hobbs Stunt Coordinator

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    Dustin brings up a good point. Most people don't listen at reference level. For that reason, it is a good idea to double check your calibration at 20 or 25 db below ref after you finish calibrating at ref. They should still balance, but you may need to add a db or two to the sub at lower volumes.

    You will not damage your speakers by calibrating to ref with the AVIA disk. Listening to very loud music or movies at ref levels may strain your system, however, since systems calibrated to ref can peak at well over 100db.
     
  6. Vince Maskeeper

    Vince Maskeeper Producer

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    Eric,

    You should understand that REF LEVEL is a strict measurement of output. The volume position, while related to output, can't be a stict universal quality in determining ref level, as a given volume knob position will offer one amount of output in a certain room, but will seem like less in a larger room.

    The REF LEVEL is, essentially, 105db of SPL out of any given speaker, maximum. Regardless of volume knob position, this is what ref means.

    To determine ref level, someone could supply you with test tones created at absolute MAX level, and you could balance your system to 105db with these tones. However this would suck, and be painful on the ears.

    So they created tones a specific number of steps below ref for you. The tones on AVIA are 20 steps below max (max should be 105db, so 20 steps below would be 85). The tones on VIDEO ESSENTIALS are 30 steps below max (max should be 105db, so 20 steps below would be 75).

    So, in your case, with receiver tones- there is no eal way to tell how many steps below max they are. So, there is no way to get an accurate number on what "ref" level is from the tones withut knowing.

    -Vince
     
  7. Eric Taylor

    Eric Taylor Agent

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    Vince thank you for the response. I finally understand it very clearly after that. I see that to get to where I need to go I will have to get the calibration disc and use my spl meter on this. I will have to get me one of them there discs soon! Thanks again!
     

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