Calibrating my SVS pb13 question ?

[TheFactor]

Well thought i'd try using my radio shack digital spl meter and avia 2 disc to calibrate my Ultra. It sounded great with just using the AVR AUTO setup but thought since I had already bought the meter and avia cd I'd give it a try . So hopefully I did it corectly.I set the spl meter at slow and at 80db , set my AVR master volume at 0 "reference level" Sub gain at about between 9 and 10 a clock. Proceeded with test tones setting all speakers at 80db using my speaker level volume on AVR and set my sub level at 83db so I guess that would be 3 db hot. Havent watched a movie yet but it sounds great for music , maybe just a little hot on the bass but blends pretty well . Going to try a movie next but thought I'd check and see if Im on the wright path . Does it sound like I did the calibrating correctly ? Thanks in advance

 

[captiankirk28]

Yes that sounds right, but i think with Avia it is supposed to be set at 85db and with out it just useing your AVR is 75db but that is very close and i could be wroung anyway

 

[TheFactor]

Yes that sounds right, but i think with Avia it is supposed to be set at 85db and with out it just useing your AVR is 75db but that is very close and i could be wroung anyway

Hmmm you could be correct on the 85db level because I did notice all my channels I had to turn down more than it was on the AVR auto setup and seems I need more Master volume then before . But just watched the beginning of IronMan and it sounded great, seems the sub blends better now than before but I am also running my Master volume on AVR closer to 0 "reference level " to get to my comfort zone on volume . Maybe I should re-calibrate and try setting everything to 85db and sub to 87db I know my channel on sub is now at -4.0 , cennter channel at -7.0, left and right channel at -6.0 and - 6.5 and sr -7.5 sl -8.5 .

 

[mnnc]

Seems like your channel trims/levels are a bit low but not far off. Depending on your prepro/recv'r it may just be the design as my levels are all about +3 or +4 to get an 80db on mains/center/surrounds...and about 83/84 on sub channel. It is important to set your sub level on preamp to about a 1/4 of the way. Example...if you can adjust sub trim -10 to +10 then a -5 would be 1/4 setting. This prevents introducing gain distortion in the signal path from preamp/recv'r. From there set your sub gain to a position where you get the desired output(87 or so). This allows you to adjust for different soundtracks bumping it up or down a bit without ever having to touch the sub itself again. Distance settings are very important and don't forget, in case you have, to set xover points for the best blend. If you have a xover system on pre that is same for all spkr's then you will have to compromise. Say your mains are rated to 40hz...set the xover to closest setting which would be about 60hz in most cases. But if your center is rated to 65hz then you have to consider it. Ideally a pre that has individual xover points is the way to go. This way you have ability to set points to just above their rated low end response so as to take full advantage of the spkr. I have my mains set to 60hz, centr 80hz, surr 80hz. Blends very nice overall, does not stress any of the main drivers, and allows the sub to do the dirty work. You have a great start to balancing things so far but consider the other aspects of setup so that you may enjoy the full potential. Btw...your settings at any given volume will be -5db less than it would imply in reference to 'reference' level. So if you are listening at -10 on volume setting...you are -15db from reference which is quite a ways away from reference considering it's double the power for a 3db gain! Bumping everything up +5db will give you referece level at a glace. On the other hand..you could set master volume to say, -10 and set all levels to 75db...this is mathematically same as setting volume to 0 and adjusting to 85db...you got me? Happy jammin'

 

[MDS]

Reference Level is 105 dB PEAK so the level of the test tones you use determines the level the SPL meter should read when calibrating. The AVIA tones are at -20 dB, so the meter should read 85 dB. The receiver's test tones are at -30 dB, so the meter should read 75 dB.

It doesn't matter whether your channel trims are positive or negative (with one minor caveat). It all depends on your room, speaker sensitivity, distance from the speakers, etc. The goal is simply to get the levels balanced and whatever value on the trims it takes to get there is correct. The caveat is that if the channel trims are positive, it will reduce the maximum number on the volume scale. You'll still be able to get the same output level though, it's just that a small gain will be applied to the signal before it gets to the main amplifier.

On the other hand..you could set master volume to say, -10 and set all levels to 75db...this is mathematically same as setting volume to 0 and adjusting to 85db...you got me?

That is correct, however only if the receiver does not automatically set the level to the equivalent of 0 dB when running the test tones (like THX certified receivers). If it does, then the position of the master volume control doesn't matter.

It's all just fun with numbers: 20 + 85 = 105 dB and 30 + 75 = 105 dB.

 

[TheFactor]

Seems like your channel trims/levels are a bit low but not far off. Depending on your prepro/recv'r it may just be the design as my levels are all about +3 or +4 to get an 80db on mains/center/surrounds...and about 83/84 on sub channel. It is important to set your sub level on preamp to about a 1/4 of the way. Example...if you can adjust sub trim -10 to +10 then a -5 would be 1/4 setting. This prevents introducing gain distortion in the signal path from preamp/recv'r. From there set your sub gain to a position where you get the desired output(87 or so). This allows you to adjust for different soundtracks bumping it up or down a bit without ever having to touch the sub itself again. Distance settings are very important and don't forget, in case you have, to set xover points for the best blend. If you have a xover system on pre that is same for all spkr's then you will have to compromise. Say your mains are rated to 40hz...set the xover to closest setting which would be about 60hz in most cases. But if your center is rated to 65hz then you have to consider it. Ideally a pre that has individual xover points is the way to go. This way you have ability to set points to just above their rated low end response so as to take full advantage of the spkr. I have my mains set to 60hz, centr 80hz, surr 80hz. Blends very nice overall, does not stress any of the main drivers, and allows the sub to do the dirty work. You have a great start to balancing things so far but consider the other aspects of setup so that you may enjoy the full potential. Btw...your settings at any given volume will be -5db less than it would imply in reference to 'reference' level. So if you are listening at -10 on volume setting...you are -15db from reference which is quite a ways away from reference considering it's double the power for a 3db gain! Bumping everything up +5db will give you referece level at a glace. On the other hand..you could set master volume to say, -10 and set all levels to 75db...this is mathematically same as setting volume to 0 and adjusting to 85db...you got me? Happy jammin'

Thanks for the tips I have my xover now set at 80 across the board since I cant adjust for fronts /center separately, maybe I should try 60 or 50 on the xover. Even though my speakers can handle much bass I have them all set to small because from what I read thats the way to go.

 

[TheFactor]

Reference Level is 105 dB PEAK so the level of the test tones you use determines the level the SPL meter should read when calibrating. The AVIA tones are at -20 dB, so the meter should read 85 dB. The receiver's test tones are at -30 dB, so the meter should read 75 dB.

It doesn't matter whether your channel trims are positive or negative (with one minor caveat). It all depends on your room, speaker sensitivity, distance from the speakers, etc. The goal is simply to get the levels balanced and whatever value on the trims it takes to get there is correct. The caveat is that if the channel trims are positive, it will reduce the maximum number on the volume scale. You'll still be able to get the same output level though, it's just that a small gain will be applied to the signal before it gets to the main amplifier.


That is correct, however only if the receiver does not automatically set the level to the equivalent of 0 dB when running the test tones (like THX certified receivers). If it does, then the position of the master volume control doesn't matter.

It's all just fun with numbers: 20 + 85 = 105 dB and 30 + 75 = 105 dB.

Thanks for the help ...