Different calibration methods for finding reference don't match up. What's right? Avia, WOW, MCACC, none? - AVS Forum
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Old 11-25-2012, 08:28 AM - Thread Starter
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I have a Pioneer Elite Receiver. When I calibrate using MCACC, reference is a full 5.5 db louder than when I use Avia and a SPL meter calibrating each speaker/sub to 85. On top of that, when I use Disney's WOW disk it says reference is 4.5 db's lower than Avia.

It's driving me nuts, I know it shouldn't matter but it bugs me that I don't know exactly how loud reference is in my room.

What's worse is, when I calibrate the subs using the receiver test tones and Avia, the results are the same, but when I try it with WOW it says my subs are 9 db hot!! WTH, very frustrating.

So, what is the most accurate way of the 3 for getting reference and calibrating the subs?

thanks
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Old 11-25-2012, 10:22 AM
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Quote:
Originally Posted by carp View Post

I have a Pioneer Elite Receiver. When I calibrate using MCACC, reference is a full 5.5 db louder than when I use Avia and a SPL meter calibrating each speaker/sub to 85. On top of that, when I use Disney's WOW disk it says reference is 4.5 db's lower than Avia.
It's driving me nuts, I know it shouldn't matter but it bugs me that I don't know exactly how loud reference is in my room.
What's worse is, when I calibrate the subs using the receiver test tones and Avia, the results are the same, but when I try it with WOW it says my subs are 9 db hot!! WTH, very frustrating.
So, what is the most accurate way of the 3 for getting reference and calibrating the subs?
thanks

Carp, I have nothing but WAGs for you. First, I'd guestt that a 4 or 5 dB difference is within the tolerances of two different uncalibrated mics/systems. Maybe reality is smack betweeen where your MCACC mic thinks it is and where your SPL meter thinks it is. As to the different results with different calibration disks, my WAG would be that slightly different frequency content of the test tones reads slightly differently in light of remaining room/speaker effects (and plus or mius ahalf decibel is to dream of/to die for or . . .
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Old 11-25-2012, 10:37 AM
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What do you mean by "reference"? All channels measure the same way high or low as applicable?

Note that THX reference level should be 4 dB higher than Dolby reference level. Is your receiver a THX rated receiver?

I recorded -20 dB FS test tones on a test CD, and reference level comes out to be near the 85 dB SPL mark upon playback.

The -30 dB FS internal test tones in my receiver come out to be near 75 dB FS, so both match.

As I recall, the THX Optimizer on the Pirates of the Caribbean disc comes out the same way.
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Old 11-25-2012, 10:37 AM
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You should be using 75db as a reference not 85. When using the rec. test tones, set the LF speaker to 75 1st as a reference for the other speakers if you have Audessy.
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Old 11-25-2012, 10:50 AM
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Quote:
Originally Posted by Kensmith48 View Post

You should be using 75db as a reference not 85. When using the rec. test tones, set the LF speaker to 75 1st as a reference for the other speakers if you have Audessy.


Avia uses -20 dB FSrms levels for the main channels, so 85 dB SPL is correct for Avia test tones.

For the subwoofer, Avia uses -30 dB FS test tones, so with the 10 dB of LFE boost 85 dB SPL is still the correct level.


http://www.ovationmultimedia.com/files/2e-AviaProAudioManual.pdf
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Old 11-25-2012, 10:54 AM
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I'll add it is pretty tough to set the subwoofer level with an SPL meter.  You may be able to get it somewhat close but from there you can adjust by ear.  Your typical volume level is going to impact the amount of bass you desire as well.

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Old 11-25-2012, 10:56 AM - Thread Starter
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Quote:
Originally Posted by Kensmith48 View Post

You should be using 75db as a reference not 85. When using the rec. test tones, set the LF speaker to 75 1st as a reference for the other speakers if you have Audessy.

Not true with Avia, you use 85dbs on the spl meter to find reference. The video essentials disk you use 75 dbs and with most receivers you also use 75, but Avia states that you used 85.

Just to make sure you guys understand the wild differences here,

Let's say MCACC calibration is correct.

Avia calibrates to 5.5 db's lower than MCACC
Disney's WOW disk calibrates to a full 10 dbs lower than MCACC

That's a huge difference.
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Old 11-25-2012, 11:03 AM - Thread Starter
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Quote:
Originally Posted by J_Palmer_Cass View Post

What do you mean by "reference"? All channels measure the same way high or low as applicable?
Note that THX reference level should be 4 dB higher than Dolby reference level. Is your receiver a THX rated receiver?
I recorded -20 dB FS test tones on a test CD, and reference level comes out to be near the 85 dB SPL mark upon playback.
The -30 dB FS internal test tones in my receiver come out to be near 75 dB FS, so both match.
As I recall, the THX Optimizer on the Pirates of the Caribbean disc comes out the same way.

Not sure what you mean by what do I mean...

It''s my understanding that the auto calibrations like MCACC set all speakers to play at reference level when the volume is set to 0, and reference level volume is the level the mixers/artist/whatever intended for playback. Not that most people listen to that loud of volumes in their homes, but that is the standard.

Calibration disks like AVIA are another way to find this reference point, that disk states that if you use a spl meter and calibrate all speakers to 85 db then you have found reference. I like setting my receiver up so that when the master volume reads 0 then I am getting 85 dbs on the spl meter, that way it's easy to see how close to reference I am while watching a movie - 10 under, 15 under, whatever.

So I adjust the level of the individual speakers so that the meter reads 85 when I have the master volume at 0 when using the Avia disk.
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Old 11-25-2012, 11:05 AM - Thread Starter
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Originally Posted by primetimeguy View Post

I'll add it is pretty tough to set the subwoofer level with an SPL meter.  You may be able to get it somewhat close but from there you can adjust by ear.  Your typical volume level is going to impact the amount of bass you desire as well.

Yeah, it's not an exact science with an spl meter, especially since you are only matching the loudest bass frequency to match with the speakers so if your sub/room has a lot of nulls and peaks you're screwed to begin with.

However, a 9 db difference between one calibration disk and another when matching subwoofer tones to speaker levels is not small.
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Old 11-25-2012, 11:06 AM
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So they difference you posted between various tone sources, was that measuring one speaker or the subwoofer?

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Old 11-25-2012, 11:15 AM - Thread Starter
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Originally Posted by primetimeguy View Post

So they difference you posted between various tone sources, was that measuring one speaker or the subwoofer?

Yeah, 2 separate discrepancies going on here.

1. Taking subs out of the equation, and just trying to find reference level I had 3 different outcomes. MCACC is 5.5 db louder than AVIA when the master volume is set to 0, and MCACC is 10 db louder than WOW disk when the master volume is set to 0.

2. Next issue. When calibrating subs flat, MCACC and Avia agree with each other but WOW disk says the subs are 9dbs hot at that setting! I use the test tones on the disk that play through the speaker and then the sub, and make sure they match on the spl meter.

Does that answer your question?

thanks
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Old 11-25-2012, 11:36 AM
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Haven't used Avia in quite some time and don't have WOW.  But just going by the numbers could the 10db difference from MCACC to WOW be a 75db/85db issue?  And the 4db from MCACC to Avia a dialnorm issue?

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Old 11-25-2012, 11:41 AM
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Quote:
Originally Posted by carp View Post

I have a Pioneer Elite Receiver. When I calibrate using MCACC, reference is a full 5.5 db louder than when I use Avia and a SPL meter calibrating each speaker/sub to 85. On top of that, when I use Disney's WOW disk it says reference is 4.5 db's lower than Avia.

It's driving me nuts, I know it shouldn't matter but it bugs me that I don't know exactly how loud reference is in my room.

What's worse is, when I calibrate the subs using the receiver test tones and Avia, the results are the same, but when I try it with WOW it says my subs are 9 db hot!! WTH, very frustrating.

So, what is the most accurate way of the 3 for getting reference and calibrating the subs?

thanks


Start all over again so I can understand you. Is your receiver a THX rated receiver?

Calibrate once with MCACC so 0 dB master volume is reference level and then leave everything alone. Your system measures how many dB SPL with the master volume set to 0 dB?

With the above calibration, Avia measures how many dB SPL with the master volume set to 0 dB?

With the above calibration, WOW measures how many dB SPL with the master volume set to 0 dB?
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Old 11-25-2012, 12:52 PM - Thread Starter
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Quote:
Originally Posted by J_Palmer_Cass View Post

Start all over again so I can understand you. Is your receiver a THX rated receiver?
Calibrate once with MCACC so 0 dB master volume is reference level and then leave everything alone. Your system measures how many dB SPL with the master volume set to 0 dB?
With the above calibration, Avia measures how many dB SPL with the master volume set to 0 dB?
With the above calibration, WOW measures how many dB SPL with the master volume set to 0 dB?

1. No, it is a Pioneer Elite VSX-53 (actually not sure)

2. I'll get back to this one...

3. Just like yesterday, with the master volume set on 0, Avia measures 90 db's on the meter.

4. I knew this was gonna hurt, so I put in my ear plugs. The WOW disk measured 95 db's db's on the meter (the sub measured 105 db's, while measuring 90 - or matched - with Avia)
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Old 11-25-2012, 12:53 PM - Thread Starter
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Quote:
Originally Posted by J_Palmer_Cass View Post

Start all over again so I can understand you. Is your receiver a THX rated receiver?
Calibrate once with MCACC so 0 dB master volume is reference level and then leave everything alone. Your system measures how many dB SPL with the master volume set to 0 dB?
With the above calibration, Avia measures how many dB SPL with the master volume set to 0 dB?
With the above calibration, WOW measures how many dB SPL with the master volume set to 0 dB?

Ok, getting back to #2. It never occurred to me that the receiver's own test tones may not match up with the MCACC auto calibration. I checked the receiver test tones (without using the automatic setup) to see how loud they were playing on the Radio Shack meter, and lo and behold they were 90 db's. -edit- I meant 80dbs -edit- This matches exactly with AVIA because the tones should be 75 db's correct?

Does that mean that the microphone used with MCACC is off, or was I initially stupid to assume that the MCACC calibration automatically makes master volume 0 = reference?

Either way, WOW disk is 5 hotter than Avia. Maybe I'm supposed to use 80db's to calibrate using WOW, but I can't find that anywhere. Also, could it be that the subwoofer test tones are purposely set 10 db's hotter than the speakers because that's what they are.
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Old 11-25-2012, 12:55 PM - Thread Starter
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My receiver says "THX Select 2 Plus" on it, not sure what that means.
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Old 11-25-2012, 03:25 PM
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Quote:
Originally Posted by carp View Post

My receiver says "THX Select 2 Plus" on it, not sure what that means.


THX receivers assume that a Dialnorm value of -27 was used for DD content. This Dialnorm value results in a 4 dB reduction in volume level, so THX units add +4 dB of gain to compensate for this reduction in volume level.. Most but not all DD DVD's use a Dialnorm value of -27.

Dolby Digital receivers assume that a Dialnorm value of -31 was used for DD content. No volume reduction with this Dialnorm value.

The AVIA disc uses a DD Dialnorm value of -31, so the AVIA tones should come out to be 4 dB (-27 - (-31) = +4) higher than standard Dolby, so your theoretical test level will come out as 89 dB (85 +4) SPL for proper THX calibration with AVIA. Your test came out to be 90 dB, so you are calibrated properly with AVIA as far as I can tell.

If you take a look at Dialnorm Offset on your display, it should show you a value of +4 for the AVIA test disc..


The bottom line is there is more than one reference level.

Dolby reference level calibrates against a Dialnorm value of -31.

THX reference level calibrates against a Dialnorm value of -27. THX units will play DD 4 dB louder than standard Dolby Digital units.

DTS reference level does not use Dialnorm.
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Old 11-25-2012, 03:43 PM
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Quote:
Originally Posted by carp View Post

Quote:
Originally Posted by J_Palmer_Cass View Post

Start all over again so I can understand you. Is your receiver a THX rated receiver?
Calibrate once with MCACC so 0 dB master volume is reference level and then leave everything alone. Your system measures how many dB SPL with the master volume set to 0 dB?
With the above calibration, Avia measures how many dB SPL with the master volume set to 0 dB?
With the above calibration, WOW measures how many dB SPL with the master volume set to 0 dB?

Ok, getting back to #2. It never occurred to me that the receiver's own test tones may not match up with the MCACC auto calibration. I checked the receiver test tones (without using the automatic setup) to see how loud they were playing on the Radio Shack meter, and lo and behold they were 90 db's. -edit- I meant 80dbs -edit- This matches exactly with AVIA because the tones should be 75 db's correct?

Does that mean that the microphone used with MCACC is off, or was I initially stupid to assume that the MCACC calibration automatically makes master volume 0 = reference?

Either way, WOW disk is 5 hotter than Avia. Maybe I'm supposed to use 80db's to calibrate using WOW, but I can't find that anywhere. Also, could it be that the subwoofer test tones are purposely set 10 db's hotter than the speakers because that's what they are.



Not all units calibrate reference level to be 0 dB on the master volume readout.

My older non THX AVR has a master volume setting of -22 dB when I calibrate for reference level. On my receiver the 0 dB readout means volume is all the way up (AKA no +1 dB on the master volume readout). My normal playback volume is in the -27 dB area (about 5 dB below reference level)

I always assumed that all consumer AVR's used a -30 dB FS test tone for calibration purposes. I made myself a non DD encoded CD with test tones encoded at -20 dB FS so I could verify calibration levels (as well as to use the disc for a few other things). Various test disc use different test levels and use different Dialnorm values, so it is very easy to get confused.
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Old 11-25-2012, 03:54 PM - Thread Starter
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Quote:
Originally Posted by J_Palmer_Cass View Post

THX receivers assume that a Dialnorm value of -27 was used for DD content. This Dialnorm value results in a 4 dB reduction in volume level, so THX units add +4 dB of gain to compensate for this reduction in volume level.. Most but not all DD DVD's use a Dialnorm value of -27.
Dolby Digital receivers assume that a Dialnorm value of -31 was used for DD content. No volume reduction with this Dialnorm value.
The AVIA disc uses a DD Dialnorm value of -31, so the AVIA tones should come out to be 4 dB (-27 - (-31) = +4) higher than standard Dolby, so your theoretical test level will come out as 89 dB (85 +4) SPL for proper THX calibration with AVIA. Your test came out to be 90 dB, so you are calibrated properly with AVIA as far as I can tell.
If you take a look at Dialnorm Offset on your display, it should show you a value of +4 for the AVIA test disc..
The bottom line is there is more than one reference level.
Dolby reference level calibrates against a Dialnorm value of -31.
THX reference level calibrates against a Dialnorm value of -27. THX units will play DD 4 dB louder than standard Dolby Digital units.
DTS reference level does not use Dialnorm.

BTW, if I haven't mentioned it I appreciate the help J Palmer.

That all makes sense to me - it bugs me that reference doesn't always mean the same thing. I always thought it meant 105 db peak for speakers at the LP and 115 peak at the LP for the LFE channel.
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Old 11-25-2012, 03:54 PM
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The WOW disc does not say what dB FS levels were used on the disc nor what Dialnorm value was used.

http://disneydvd.disney.go.com/managed/WOW_Manual.pdf


Speaker Level Adjustment

SPL METER REQUIRED
ADVANCED AUDIO SET Up TOOLS
SPL METER NOT REQUIRED

This test will allow you to adjust the level of each speaker to ensure
that your system is balanced from left to right and from front to
rear. When properly adjusted, the speakers will produce the most
lifelike sonic presentation and allow a soundtrack to be heard as
the producer and recording engineer intended.

The test signal used will be band-limited pink noise. If you have
remote control capability for level adjustment on your system, use
the remote to begin the test, seated in your normal viewing position.
Adjust the individual channels for equal volume at that position.

For best results, use a sound pressure level meter to adjust channel
levels. A comfortable volume is usually between 78 dB and 85 dB
as measured on a Radio Shack or equivalent sound level meter set
for c weighting and slow response.

It is important to keep in mind that music and sound tracks are
dynamic, that is they have loud and soft passages. Properly setting
the levels should allow the loudest passages to have impact without
distorting the sound.

As you set your levels, do not try to set them at maximum volume.
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Old 11-25-2012, 04:02 PM
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The WOW subwoofer level setting is described below.


SUBWOOFER LEVEL ADJUSTMENT

SPL METER REQUIRED

This portion of the audio test is specifically for subwoofer setup.
If you do not have a subwoofer or it is not connected to your
receiver, please proceed to the next audio test.

Just like the other speakers in your system, the subwoofer should
not be set for maximum output. Because this is a very demanding
test, prior to commencing, be sure to reduce the level of the
subwoofer to no more than 50% of its maximum output.
test

The band of pink noise generated by this test is specifically directed
to the lFE channel (low frequency effects) and will help you position
your subwoofer to the most desirable location in your listening
environment that will allow you to get the maximum volume without
distortion. Once this position is located, often in or near a corner,
select the phase setting (if one is available) for maximum volume
without distortion.

You will now need to adjust the subwoofer level control to 3 dB
higher than the sound pressure level used during the speaker level
adjustment section on this disc.
If you find that the subwoofer
volume control is set for maximum, you will need to reduce the
sound pressure level used during the level adjustment test in the
previous section by approximately 3 dB. Then, repeat both tests.
A properly calibrated subwoofer will reduce the potential for
distortion or premature failure.
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Old 11-25-2012, 04:09 PM
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Quote:
Originally Posted by carp View Post

Quote:
Originally Posted by J_Palmer_Cass View Post

THX receivers assume that a Dialnorm value of -27 was used for DD content. This Dialnorm value results in a 4 dB reduction in volume level, so THX units add +4 dB of gain to compensate for this reduction in volume level.. Most but not all DD DVD's use a Dialnorm value of -27.
Dolby Digital receivers assume that a Dialnorm value of -31 was used for DD content. No volume reduction with this Dialnorm value.
The AVIA disc uses a DD Dialnorm value of -31, so the AVIA tones should come out to be 4 dB (-27 - (-31) = +4) higher than standard Dolby, so your theoretical test level will come out as 89 dB (85 +4) SPL for proper THX calibration with AVIA. Your test came out to be 90 dB, so you are calibrated properly with AVIA as far as I can tell.
If you take a look at Dialnorm Offset on your display, it should show you a value of +4 for the AVIA test disc..
The bottom line is there is more than one reference level.
Dolby reference level calibrates against a Dialnorm value of -31.
THX reference level calibrates against a Dialnorm value of -27. THX units will play DD 4 dB louder than standard Dolby Digital units.
DTS reference level does not use Dialnorm.

BTW, if I haven't mentioned it I appreciate the help J Palmer.

That all makes sense to me - it bugs me that reference doesn't always mean the same thing. I always thought it meant 105 db peak for speakers at the LP and 115 peak at the LP for the LFE channel.


I recommend that you make yourself an audio test CD with standard known recording levels. No DD and Dialnorm complications. I use -20 dB FS tones because they are easy to listen to at my standard master volume settings. The -30 dB test tones were just a bit too low in volume level for other tests.

I have additional test signals that I use for TrueRTA and for SpectrumLab, and I know that the -20 dB FS signals are best for all around use.
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Old 11-25-2012, 04:10 PM - Thread Starter
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Yeah, I read that while watching the disk right before you posted. +3 doesn't make up for the fact that they are +10 hot compared to receiver tones and Avia. I'm starting to think the WOW disk might not be the way to go....
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Old 11-25-2012, 04:12 PM - Thread Starter
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Quote:
Originally Posted by J_Palmer_Cass View Post

I recommend that you make yourself an audio test CD with standard known recording levels. No DD and Dialnorm complications. I use -20 dB FS tones because they are easy to listen to at my standard master volume settings. The -30 dB test tones were just a bit too low in volume level for other tests.
I have additional test signals that I use for TrueRTA and for SpectrumLab, and I know that the -20 dB FS signals are best for all around use.

Great idea, this sounds good. Do you know where I can find reliable tones online?
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Old 11-25-2012, 04:40 PM - Thread Starter
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Great thanks man. I'll post how it turns out.
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Old 11-26-2012, 09:58 AM
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Quote:
Originally Posted by J_Palmer_Cass View Post

I recommend that you make yourself an audio test CD with standard known recording levels. No DD and Dialnorm complications. I use -20 dB FS tones because they are easy to listen to at my standard master volume settings. The -30 dB test tones were just a bit too low in volume level for other tests.

I have additional test signals that I use for TrueRTA and for SpectrumLab, and I know that the -20 dB FS signals are best for all around use.

I'm inspired to do this with MCH flac files to avoid any dialnorm issues. Just to clarify, a -20 dB FS tone with volume at Zero should calibrate to 75db? Or 85?
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Old 11-26-2012, 10:41 AM
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A standard single channel "reference level" calibration should result in 105 dB SPL for a 0 dB FS peak input signal recorded on the test disc. This is not the 0 dB on the master volume control of the AVR. Some AVR's use 0 dB on the master volume for calibrated reference level, and some do not do so.

With an input signal level of -20 dB FS peak the output level will be 85 dB SPL.

With an input signal level of -30 dB FS peak the output level will be 75 dB SPL.

You can really use any input signal level that you want to use, but the above two input levels are commonly used.


Some test signals use a dB rms value, so you have to watch out for that issue. For example REW uses dB rms levels for its signal generator.
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Old 11-26-2012, 11:10 AM
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Thanks for the clarification on the RMS vs Peak. I was just wondering about that. For instance, I just downloaded some test tones from Blue Sky to see what their band-limited pink noise waveform looked like. While their average was -20.14, the peaks were in the -12-10 range. I guess the lesson here is that the SPL meter will be giving me it's reading of those -12 dB peaks and not the avg of -20.

With that in mind, when creating the noise, should there be a consideration of the RMS dB FS values? I can start with noise of any level, and hard limit the peaks to -20. But I could have range of possible RMS levels within the constraint of -20 peaks.
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Old 11-26-2012, 01:14 PM
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I have a RS Digital SPL meter, and if I set the meter to C scale Slow (or Fast) and Average, then the meter reads the RMS SPL level. If I set the scale to MAX, then the meter reads the Peak SPL level.

You could have a problem with pink noise if you set the level to -10 dB FS. Then you would be clipping the PEAKS because the PEAKS are about 12 dB above -10 dB FS. I just measured the PEAK and RMS level on TrueRTA using TrueRTA's test pink noise and the PEAKS were about 11.5 dB above the RMS average level.

If you want a -20 dB FS test signal, use the -20 dB FS number on the signal generator for a single channel signal.
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Old 11-09-2014, 11:17 PM
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Visiting this page after reading Archaea eq comparison thread

Can someone verify if the DTS audio check video file (from demo-world) is -20 or -30 dBFS : ?
Can I use it for reference volume level setting?
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