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Basic Audio Calibration


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#26 skinXBWAU

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Posted 27 March 2006 - 10:11 AM

Mark,

I calibrated by 5.1 system using the Radio Shack SPL so that all speakers (except LFE) read 75 Db. My master volume was set to -20 Db as 00 Db was just too loud and I was worried about causing my Receiver to distort.

Is this setup fine if I watch films at -20 Db? I find this a comfortable level for stereo music also.

#27 MarkTecher

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Posted 27 March 2006 - 04:44 PM

Yes the band limited pink noise is loud if your not used to it. The only thing I would be concerned with by calibrating at -20, is where did the trims end up. Generally, you have +/-10dB on the trims, and as a rule of thumb, I prefer to see the trims in the negative figures rather than the positives. By starting out at -20dB, I feel that your trims would have to be pushed well into the + figures to read +75dB on the meter.

If you don't like the noise, you can start by turning all trims to -10 (or what ever their lowest level is) first so that when you activate the test tones, they don't cause you distress.

Then take the reading with the master volume at 00dB and increase eack trim as needed to read +75dB. The only time you really need to be under 00dB for the master volume is when the room is very small, ans the trims won't go down low enough to read +75dB. In those cases (rare) I calibrate at -10 or -15 (worst case).

Hope that helps...

Mark

#28 :)

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Posted 27 March 2006 - 04:58 PM

Mark,

I calibrated by 5.1 system using the Radio Shack SPL so that all speakers (except LFE) read 75 Db. My master volume was set to -20 Db as 00 Db was just too loud and I was worried about causing my Receiver to distort.

Is this setup fine if I watch films at -20 Db? I find this a comfortable level for stereo music also.


skin another option is to calibrate at say -15db vol level setting and adjust speaker levels till you get 60db on your spl meter. Theoretically then if you put your vol level to 00db vol level you should then get 75db out of yoru speakers. After calibrating at 60db and -15db vol level setting you can also then do a quick whip aroudn the speakers to make sure you do infact get 75db with vol at zero.

Another option - use some ear plugs ! and jsut watch the needle on the spl meter and indicater on the pre-pro telling you which speaker level your checking ! :blink:

#29 RodN

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Posted 27 March 2006 - 07:54 PM

I agree with Al here, unless you have a busy street or something just callibrate everything at 70db. After all the result is balance between the channels and that doesn't need to occur at too high a level.

#30 skinXBWAU

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Posted 27 March 2006 - 09:28 PM

These are my trim levels:

FL - (-20 master volume)
C - (-3)
FR - (-20 master volume)
RR - (0)
RL - (0)
LFE - (-13)

#31 JoshH

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Posted 27 March 2006 - 10:28 PM

Quote "I calibrated by 5.1 system using the Radio Shack SPL so that all speakers (except LFE) read 75 Db. My master volume was set to -20 Db as 00 Db was just too loud and I was worried about causing my Receiver to distort."


You are supposed to use band limited pink noise when calibrating 75 DB C weighted 0 DB reference level - not full pink noise.

Thats why you nearly blew your ears off and were worried about receiver distortion.

And your subwoofer should be calibrated accordingly.

You CANNOT calibrate at -20B and acheive accurate results with full pink noise.

Forgot to add - DONT use your internal receivers pink noise generator - unless you have a THX or top of the line RX it will not be accurate. Use a test DVD for more accurate readings.

Edited by WORX A4, 27 March 2006 - 10:30 PM.


#32 skinXBWAU

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Posted 27 March 2006 - 10:36 PM

I have DVE-PAL, I could use that.

What's the difference between "band limited" and "full" pink noise?

#33 JoshH

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Posted 27 March 2006 - 10:42 PM

I have DVE-PAL, I could use that.

What's the difference between "band limited" and "full" pink noise?


Band limited pink noise is just that - its 'band' limited.

If you want to see [rather hear] the difference - set your receiver to 0DB and play band limited pink noise from DVE [or any test disc] followed by normal pink noise.

The difference is clearly audible - full pink noise will make you wince - band limited will allow you to comfortably and accurately calibrate.

Edit - and make sure you have your spl meter set to C weighted 'slow' and aimed at a 45 degree angle forward from the seated ear position.

#34 MarkTecher

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Posted 27 March 2006 - 11:03 PM

Skin,

If your using DVE, then select the DD audio only and start with the 5.1 tests. The first run through are band limited pink noise. Whilst is has a DN+4 value, it does actually equal the THX +75dB output for the LCR.

The surrounds are too low, and when using a meter, you will be forced to turn them up to read the same as a screen channel. If you do this, come movie playback time, your surrounds will be too high (by 3dB!). So if you use +75 for the LCRs, then you need to be using +72dB for the surrounds. This is the only time you would do this!!!

The LFE track is also 13dB too low. Do the math so that your level (the level you want is +79dB) is 79 - 13dB which is equal to 66 on your meter...

Again, the disc is useful (an awesome video tool), but it has some problems that need to be taken into consideration so that you get good results for audio as well...

Mark

#35 skinXBWAU

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Posted 27 March 2006 - 11:29 PM

Mark,

I don't know if I fully follow you there. But tomorrow, I will give DVE a go.

If I turn the LFE up 13 dB it is way too loud. I used the 80 dB range on the SPL Metre to set it to the right level as per your instructions.

I don't understand why the surrounds are 3 dB too high either.

#36 mcfeast

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Posted 28 March 2006 - 12:39 AM

hey i live 10mins from brissy CBD - i would like to pay someone who has an SPL meter to tweak my system for me.

So some help from a guru would be very much appreciated.

thanks guys.

Edited by mcfeast, 28 March 2006 - 12:44 AM.


#37 Wacko02

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Posted 28 March 2006 - 11:19 AM

I noticed that the Yamaha RXV-800 that i'm using has several test tones for setting levels. It's got a broad spectrum (pink noise?) which is just lots of hissing noise. Then it has the option to set it for a certain frequency output. From memory this ranges from 120 Hz to 220 Hz or thereabouts.

Is this any use in setup? And is this the same as band limited? Using the test tone at a set frequency is much easier on the ears.

#38 JoshH

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Posted 28 March 2006 - 12:43 PM

I noticed that the Yamaha RXV-800 that i'm using has several test tones for setting levels. It's got a broad spectrum (pink noise?) which is just lots of hissing noise. Then it has the option to set it for a certain frequency output. From memory this ranges from 120 Hz to 220 Hz or thereabouts.

Is this any use in setup? And is this the same as band limited? Using the test tone at a set frequency is much easier on the ears.


Hard to know as I dont have first hand experience with your unit. From your description of what Yamaha call it - its not band limited pink noise - in general however, you are MUCH better off using a test disc than internal noise generators.

I have seen internal noise generators that are off by more than 10db so if you can use a test disc.

#39 MarkTecher

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Posted 28 March 2006 - 05:08 PM

hey i live 10mins from brissy CBD - i would like to pay someone who has an SPL meter to tweak my system for me.

So some help from a guru would be very much appreciated.

thanks guys.


Send me a PM...

Mark

Mark,

I don't know if I fully follow you there. But tomorrow, I will give DVE a go.

If I turn the LFE up 13 dB it is way too loud. I used the 80 dB range on the SPL Metre to set it to the right level as per your instructions.

I don't understand why the surrounds are 3 dB too high either.



I can't remember if your AVR has a relative or absolute volume reading. Most digital Yammies have releative.

Get you meter set up to the 70dB scale, C and slow...

Load the disc and select the 5.1 tones...

You might want to reduce the levels of all trims first.

Play disc and tone for the left front channel...

Turn the Master Volume to 00dB observing the level on the meter. The reading should be +75dB. If you do not have trims on the left and right front speakers, then find a number that does read +75dB...

Adjust the centre and right to read +75dB...

Adjust the Surrounds to read +72dB...

Adjust the Sub to read just 66 dB...

All should be done from the 70dB scale as 66 is also measurable from the 70dB range as well...

Then load a film and have a listen...

Please report back...

Mark

#40 RodN

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Posted 28 March 2006 - 08:25 PM

Don't worry about what the receiver is saying all levels are relative to each other. Turn it up until you hit 75db on the SPL meter then cycle through the other speakers and adjust to suit, simple.

#41 Kirium

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Posted 30 March 2006 - 11:02 PM

Got the radioshack SPL meter today... calibrated tonight using the rxr internal tones, but the full band pink noise was a bit harsh.. especially at 85dB.

I'll crack out DVE tomorrow and use the tones on there and cal for 75dB. See how it goes...

#42 MarkTecher

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Posted 31 March 2006 - 12:13 AM

Got the radioshack SPL meter today... calibrated tonight using the rxr internal tones, but the full band pink noise was a bit harsh.. especially at 85dB.

I'll crack out DVE tomorrow and use the tones on there and cal for 75dB. See how it goes...

Using the ITG tones, you should have been at +75dB not +85dB unless your manual states otherwize...

Mark

#43 RodN

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Posted 31 March 2006 - 09:00 AM

Got the radioshack SPL meter today... calibrated tonight using the rxr internal tones, but the full band pink noise was a bit harsh.. especially at 85dB.

I'll crack out DVE tomorrow and use the tones on there and cal for 75dB. See how it goes...


Just remember the sub-tone on DVE is about 10-12db down.

#44 Kirium

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Posted 31 March 2006 - 06:10 PM

The sub tone started pegging the meter. I don't think the vol control on the sub is set real high either... hard to tell with the Velodyne because it's remote push button, not a knob. The led on the sub flashes a different number of times depending on vol level... I'll have to crack out the destructions and figure out what level i should start at.

#45 RodN

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Posted 31 March 2006 - 06:57 PM

The sub tone started pegging the meter. I don't think the vol control on the sub is set real high either... hard to tell with the Velodyne because it's remote push button, not a knob. The led on the sub flashes a different number of times depending on vol level... I'll have to crack out the destructions and figure out what level i should start at.


Yes from memory I should say the signal itself is about 10db HOT - making you adjust it 10db DOWN the wrong way if that makes sense. You'll see when you set all the other speakers up.

#46 skinXBWAU

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Posted 30 May 2006 - 09:12 AM

Why hasn't this thread been made sticky yet?

It has helped me a lot. :blink:

#47 ae93gti

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Posted 30 May 2006 - 09:53 AM

Why hasn't this thread been made sticky yet?

It has helped me a lot. :blink:

It is (sort of) in Al's HT FAQ.

SYSTEM SETUP

Q Test material ? Movies & TV, Music DVDs, Hi-Rez(DVDA/SACD), CD, Vinyl?, Classical

Q Setting Levels ? DVE, How to?, Reference?, Listening level?, SPL meter

Most people should read this first anyway but perhaps a separate sticky??

#48 MarkTecher

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Posted 30 May 2006 - 09:57 AM

The sub tone started pegging the meter. I don't think the vol control on the sub is set real high either... hard to tell with the Velodyne because it's remote push button, not a knob. The led on the sub flashes a different number of times depending on vol level... I'll have to crack out the destructions and figure out what level i should start at.


I would suggest to start at the lowest setting and work up using the SPL meter to allow you to know when you have achieved the correct level. As has been mentioned, DVE's sub tones are 12dB too low. So you need to work on the fact that with a proper level tone you want 79dB. Because these tones are 12dB lower, the level you want to see on the meter is 79 - 12 = 67...

The levels wil sound low for the tones, but should match for other discs...

Mark

#49 skinXBWAU

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Posted 30 May 2006 - 10:10 AM

It is (sort of) in Al's HT FAQ.

Most people should read this first anyway but perhaps a separate sticky??


That's a very good point ae93gti. I always forget about that FAQ.

#50 dvd-whore

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Posted 30 May 2006 - 01:36 PM

QUOTE "DONT use your internal receivers pink noise generator - unless you have a THX or top of the line RX it will not be accurate. Use a test DVD for more accurate readings."

http://pioneer.com.a...1015/index.html

This states THX Select 2, would the pink noise generator be correct for this audio calibration?