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Discussion Starter · #1 ·
How do you guys calibrate your sub to your system? I have a sound meter and Avia disk, but I'm not sure what SPL my sub should be compared to my other speakers. It seems like during the test my sub was louder on the meter than my other speakers. But, my sub is also louder during different frequencies. So how do you deal with that? Any tips will be appreciated.


Thanks,

Casey
 

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Avia is a Dolby Digital format, and relies on redirected bass in order to calibrate the subwoofer level. This requires the speakers to be set to small, and the speaker channel in question will then contribute bass to the subwoofer tone.


The amount of bass each speaker contributes to the sub tone is highly dependent on its room location, its inherent bass capabilities, its proximity to the subwoofer, the phase setting of the subwoofer, and the crossover frequency selected.


The best way to calibrate the subwoofer with Avia is to run the sub test tone for each speaker channel and note the results. Pick the channel that seems most representative of the average, and use it for final sub calibration. This method will tend to eliminate over or under calibration by disregarding the highest and the lowest values and using the average.


Also, a good way to evaluate the effect of the phase control when using Avia is to run the sub calibration tone for the speaker closest to the subwoofer and try the phase at 0 and then at 180. Observes what happens on the SPL meter. Usually one setting will be considerably higher than the other, indicating the subwoofer and the nearest speaker are the most "in phase" at that phase setting. This may not be completely desirable from a smooth FR standpoint, but it can help you understand the effect of the phase control, since Avia does rely on redirected bass.


For calibration levels, set the master volume to 0.0, and set each channel to 85 dB at the listening position, and set the subwoofer to 83-86 dB using the most representative channel as discussed above. The RS meter reads about 2 dB low on the Avia test tone, so a reading of 83 dB would be about flat, and 86 dB would be a little hot.
 

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Discussion Starter · #4 ·
Hmmm I tried out the test. Are you talking about using the test where the pink noise alternates between each channel and the sub? I calibrated my left and right mains to the sub at the same level, but the test with my center channel makes the sub very loud. Also, when I do the warble test the sub is going way over 85db. Does this sound right?
 

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I have a question regarding the RS analog meter:


When I measure at 85db with the meter in the '80' position, then switch to the '90' position, the meter almost always reads about +2 db (87db). The same is true if calibrating at 75db and using the '70' & '80' dial positions.


Any explanation for this?
 

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For 85dB using the 90 setting, the needle should on the left side of the scale. Seems like somethings wrong with your meter.
 

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Quote:
Originally Posted by likemav
I have a question regarding the RS analog meter:


When I measure at 85db with the meter in the '80' position, then switch to the '90' position, the meter almost always reads about +2 db (87db). The same is true if calibrating at 75db and using the '70' & '80' dial positions.


Any explanation for this?
Yes. The internal amp will clip if the needle goes past +4, so always switch to next range if at or over +4 dB.
 

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Not sure what the confusion is here.

The instructions on the sub level screen say to match the level of the sub with speaker playing.

When I run the test I use my left speaker (since that's the first one played) and simply match my sub to the db output of my left speaker.
 

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Quote:
Originally Posted by Ilkka
Yes. The internal amp will clip if the needle goes past +4, so always switch to next range if at or over +4 dB.
Godammit Ilkka, now I have to measure everything again! ;)
 

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Discussion Starter · #10 ·
Quote:
Originally Posted by braidkid
Not sure what the confusion is here.

The instructions on the sub level screen say to match the level of the sub with speaker playing.

When I run the test I use my left speaker (since that's the first one played) and simply match my sub to the db output of my left speaker.
Do you mean you match it while the left speaker and sub are playing at the same time? Or you measure the left speaker by itself, then the sub, then match it? Also, why is it if I match the sub by itself to the left speaker, it's so much louder when it alternates from the center speaker?
 

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Casey:

You need to make sure your main speakers are balanced to at least within 1 db of each other first before doing the sub. "Main Speaker' DVD section Look for the '5 channel balance'.


Also sounds like you have your Left and Right speakers set to "large" in your bass management. Try setting all speakers to "small". Better for the receiver amp anyway as far as power availability and clipping. It would be capable of higher SPL levels due to amp not having to amplify the bass if set to 'small'.


Usually set the sub output to a couple of db higher than your speakers. The meter response at the bass frequencies is a bit lower than the midrange frequencies used in the speaker test(s).


You may encounter a room mode at the sub test. It tends to excite modes from 40-50 Hz which is what the test is using. It did on my system, about a 15 db boom from 47-49 Hz which made all the other bass freqs. way too weak and I didn't know about room modes and parametric EQs like the Behringer Feedback Destroyer and RTA software back then. Now I do ;) and it sounds soooo much sweeter now. 'Irene' scene from 'Black Hawk Down' is a nice subjective test for the deeper tones (lower than 30 Hz) especially turned up. Hehe. ;) :D Try it sometime.
 

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Quote:
Originally Posted by caser85
Do you mean you match it while the left speaker and sub are playing at the same time? Or you measure the left speaker by itself, then the sub, then match it? Also, why is it if I match the sub by itself to the left speaker, it's so much louder when it alternates from the center speaker?
Are you using Avia? Before you get to the sub setup page you should have already gone throught the speaker set up page and set all speaker levels to 75 or 85db. Once you get to the sub setup page it starts with the left channel and sub alternating and says to match the sub level to that of the speaker channel being played.


If your center speaker is much louder than your left channel, your speaker levels are not matched and you need to do this before anything else.
 

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Quote:
Originally Posted by Ilkka
Yes. The internal amp will clip if the needle goes past +4, so always switch to next range if at or over +4 dB.
Afterhought- Then how come everyone's meter doesn't do this? Mine doesn't. The OP is measuring straight SPL.

Quote:
Originally Posted by braidkid
Are you using Avia? Before you get to the sub setup page you should have already gone throught the speaker set up page and set all speaker levels to 75 or 85db. Once you get to the sub setup page it starts with the left channel and sub alternating and says to match the sub level to that of the speaker channel being played.


If your center speaker is much louder than your left channel, your speaker levels are not matched and you need to do this before anything else.
Agreed. It mostly recommended that you calibrate to 85dB. First, calibrate the center channel to 85dB (AVR CC level 0). Use the AVR level controls for the for the remaining SPEAKERS to achieve 85dB. Match the sub with the speaker that's closest to it.


I would post a link to a thread I started "My First Calibration, Help Please" but the server is too busy. Try searching off peak under threads started by JeffD2. (note the dot at the end). Lots of very knowledgable people chimed in.
 

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Discussion Starter · #14 ·
I am using Avia. I do have my main speakers calibrated to the same level. What I mean is that even though the speakers are playing the same level, the sub is playing different levels based on the speaker. So for the left, I'll match it to 85db. Then the center plays at 85db, but the sub plays at 100db right after that. So that's what I don't get. Why does the sub play at different levels based on each speaker and which one do I calibrate it to?


Thanks for the tips so far.
 

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It appears to me you have not calibrated the sub to the speakers as mentioned by braidkid or followed basic setup procedures.


AVR- no sound enhancement (cinefilter, THX limiting. Speakers set to small. 80Hz crossover. CC level set to -5 (on-10 to +10 scale).


At the sub- Phase to zero. Gain set to 1/4 - 1/3. If crossed. set to highest setting. No port plugging, etc.


Anyway, the calibration thread I mentioned now can be found on the system calibration page of my website. Good Luck! :)
 

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Quote:
Originally Posted by caser85
I am using Avia. I do have my main speakers calibrated to the same level. What I mean is that even though the speakers are playing the same level, the sub is playing different levels based on the speaker. So for the left, I'll match it to 85db. Then the center plays at 85db, but the sub plays at 100db right after that. So that's what I don't get. Why does the sub play at different levels based on each speaker and which one do I calibrate it to?


Thanks for the tips so far.
What you are experiencing is normal with Avia since the sub tones in Avia are run through the main speakers and rely on your bass management to get the signal to the sub. The reason for the variance is that different speakers are reacting differently with the sub, causing combined peaks in some cases and combined cancellations in other cases.


TAKE ED MULLEN'S ADVICE in his earlier post. Find the speaker that best represents the average and use that for calibration. I would also add that I think it should be one of the front three speakers that you use, but you make the call.


One final piece of advice, and this is the one you probably won't like (I know it drove me crazy). Once you get it calibrated, tweak it using your ears and some bass heavy music. Subs and room interactions are crazy. A sub calibrated perfectly with Avia (or any disc) will sound different in different rooms. I used to have to calibrate a few dB's hot to get the sound I liked. Now after moving my sub around I get a +-4dB frequency response throughout the subs range which is pretty flat for my troubled room. I now calibrate my sub to 82 with Avia (which is actually right when you take into account the meters innacuracies), and actually get better, tighter and believe it or not more bass with the lower setting.


Use the meter first, but don't be afraid to adjust to taste after that.


Greg
 

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I run dual subwoofers, and I get a 3-4 dB higher Avia sub tone reading from the left/right mains, as compared to the center channel. That is because each main is close to its respective subwoofer and there is acoustic coupling. Also the mains have somewhat better bass capability than the center channel.


A 15 dB variation going from a main to the center channel is pretty major. As Jeff says, all the speakers need to be calibrated and balanced first before the subwoofer can be calibrated. Even then there shouldn't be that big of a swing between speaker channels on the subwoofer tone.


I do agree with Greg that one of the three front stage speaker channels is probably most appropriate to use for subwoofer calibration. And definitely you will get some variations in calibration level due to room acoustics. Fellow Secrets contributor Paul Taatjes has done some experiments regarding calibrating to a peak or a null, and it certainly affects the overall subwoofer calibration level.


If you want to take things to the next level, start thinking about plotting the in-room FR in the bass region. Consider building some bass traps to reduce the severity of any modes (standing waves causing big peaks and nulls). After bass trapping, invest in a PEQ to fine tune the FR.
 

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Quote:
Originally Posted by caser85
I am using Avia. I do have my main speakers calibrated to the same level. What I mean is that even though the speakers are playing the same level, the sub is playing different levels based on the speaker. So for the left, I'll match it to 85db. Then the center plays at 85db, but the sub plays at 100db right after that. So that's what I don't get. Why does the sub play at different levels based on each speaker and which one do I calibrate it to?


Thanks for the tips so far.



How does the calibration come out if you use the receiver's test tones instead of Avia?


I just set all my speakers to even with the receivers test tones for starters, and then fine tune the subwoofer level in the two channel mode with a music source CD of known bass quantity.
 

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