# Help with speaker calibration!!!



## Guest (Mar 15, 2007)

Sorry for the lengthly post, wanted to get it all out.

I am a bit new to this...

I have been reading much on calibrating speakers and subs. My setup is a 5.1. the AV is a Denon 2807, the sub being a SVS PB12-Plus, with Ascend CBM340se fronts and center, and 170se surrounds. In what I have been reading, it states to set the master volume on my receiver to 00db, which I believe to be 100% volume, is that correct? Also, I am reading that I should run the gain FULL UP on the sub, again 100% max volume. I am very confused as I feel that this is 100% volume and do not want to damage any equipment. I have figured out how to adjust the speaker levels on the AV, just want to know a little more on SPL how to and setting the sub up properly on the subs panel. Here is what I have read in a nutshell and a little more clarity or a link that better explains what to do would be great! I have a Galaxy CM-140 SPL meter. I also have for calibrating Avia and DVE.

Make sure your receiver/processor master volume is set at "00 dB" or other easy to remember level; it will become your "reference level", one very close to that intended for home theaters by Dolby Labs. And finally, set your subwoofer amp’s volume control. Note here, if you have a "PC-type" subwoofer put the volume/gain knob to no more than 1/4th to 1/3rd of the way up. If it's a separate pro-type amp (like the Samson amps we sell) for a CS-type subwoofer, run the gain FULL UP (it's a different sort of amp design after all and expects to be set up this way). It’s a good idea to check the subwoofer level control of your receiver before you begin the test tones. Keep the receiver's subwoofer output control to about 25% up or lower than "0 dB" (or say -6dB given a typical receiver channel limits of –12 dB to +12 dB) . This will allow your amp to work with the cleanest signal possible from your receiver, while still leaving plenty of downward adjustment you can use from your viewing position (using the remote). As the tones start, alternating, speaker to speaker (watching your sound meter now) set each speaker’s volume to 75 dB or 85dB (depending on your tone source), using the receiver’s channel controls. Not all test disks or receivers are the same when it comes to calibration tones however, if using a test DVD like Video Essentials should allow you to calibrate reference level at 75dB. Ovation's "Avia" DVD is recorded at a higher level to improve signal to noise ratios during calibration, so you need to measure instead to 85dB for all channels if you use it and not Video Essentials (discussion below, regarding a "boost" to your LFE still applies but you simply add the bump you want above and beyond 85dB, vice 75dB).


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## Sonnie (Apr 11, 2006)

Hello Alowe and welcome to the Shack!

We have a little bit in common... I own a couple of the SVS PB12-Plus/2's and my Denon 2807 should be here today.

As far as calibrating speaker levels, just use the Auto-Setup in the Denon receiver. Of course you'll want to double check it so that it gets it right. Generally it likes to set your speakers to Large when they should be Small. It will also sometimes stick an unreal distance in there for your sub. You can also check the levels with the SPL meter to make sure they are all correct.

For taming the response of your sub, use REW (Room EQ Wizard) and your CM-140 for measuring the response. Measure your sub only to start with. This will determine if you need a BFD, which will in turn determine your sub pre-out level since the input on it has to be set accordingly. Generally we setup the sub pre-out for the BFD input and then level match our sub with the mains using the subs own amp volume control.

Check out the Sticky Threads in the BFD | REW Forum for more info on REW and the BFD.


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## Guest (Mar 15, 2007)

Thanks Sonnie,

Will read up on that now. Seems like an awful lot of things to do in that software to calibrate speakers though? Is it good for the newer person to attempt?


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## Sonnie (Apr 11, 2006)

It was all new to us at some point in time, but we wanted to learn it and did. There is no easy way to get it done really. Once you start diving in, reading a little and start working with it, it becomes second nature for the most part. I still run into a snafu all along myself. Basically get the bulk of it down and take a few measurements. The REW Help Files will get you that far. Then if you have questions, we'll be here for you. It ain't that bad really, it just looks intimidating. :T


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## Prof. (Oct 20, 2006)

Sonnie said:


> It will also sometimes stick an unreal distance in there for your sub. You can also check the levels with the SPL meter to make sure they are all correct..


Be careful of the distance setting for the sub. that the Auto setup calibrates..and for that matter, the fronts as well
Most AVR's do set a distance different than the actual measured distance, and the reason for this is that it takes any delays into account..particularly noticeable if you have your speakers behind a screen wall..
It may only be a few inches, and certainly if there is a big difference then you will need to adjust it manually yourself..


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## Sonnie (Apr 11, 2006)

Yeah... I'm talking about it setting the subs to 18' when they are really only 10'. If it's close, I would not alter it.


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## bobgpsr (Apr 20, 2006)

Don't forget that a parametric eq like a BFD and the sub's amp & phase control can also add to the delay. IMHO I would actually trust an automatic calibration by an AVR to get the sub "distance" right more than any tape measure. The important thing is time of arrival of the sound wave. The AVR's digital signal processor and mic can measure this and get it right.


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## Sonnie (Apr 11, 2006)

So if it sets it up at 18' when it's really 10', you would not change it? This is not uncommon at all for receivers to do this... especially the Yamaha's from what I've read. However, I don't know of any one who has left it at the distance set by the receiver.


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## Guest (Mar 16, 2007)

I got is setup with Avia. Main set at 00 dB and all speakers hitting 85 dB. Only thing is that I had to really up the speaker volume in the AV around + 7 - 8. Is that common to have to up the speakers that much to achieve that dB level. 85 dB is the correct level I should be shooting for with Avia correct?


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## Otto (May 18, 2006)

Alowe said:


> I got is setup with Avia. Main set at 00 dB and all speakers hitting 85 dB. Only thing is that I had to really up the speaker volume in the AV around + 7 - 8. Is that common to have to up the speakers that much to achieve that dB level. 85 dB is the correct level I should be shooting for with Avia correct?


Hi there Alowe,

85 dB is an OK target, but I don't think it really matters much. I usually use a target of 75 dB, and I use an SPL meter to determine levels. Also, the -0 db on the receiver is arbitrary for the most part.

I usually set all channel levels to 0. I then set up my meter in the listening position, and turn up the master volume until one of them (usually one of the mains or the center) reads 75 dB on my SPL meter when using a C weighting (note that at this point, the master volume doesn't necessarily read 0 dB on the front panel of my preamp). I then adjust all other channel levels until each reads 75 dB on the SPL meter. That's it.

If you did it at 85 dB, and 0 on your front panel, that's OK. The only thing that I might not like about it is that you are pushing your individual channel levels by 7 or 8 dB. There's nothing wrong with adjusting those levels, but I just like to keep them "around" 0. So, my mains might be set to 0, center +3, surrounds -1. It gives me more flexibilty in adjusting them later to taste, if needed (infrequently I will bump my center by 1 or 2 dB, depending on program material).


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## Guest (Mar 16, 2007)

Otto said:


> Hi there Alowe,
> 
> 85 dB is an OK target, but I don't think it really matters much. I usually use a target of 75 dB, and I use an SPL meter to determine levels. Also, the -0 db on the receiver is arbitrary for the most part.
> 
> ...



Thanks all! I got it all figured out! Now on to REW. I got the SPL meter connected to my laptop and the program seems like it is reading the MIC, just not sure how this connects to the AV. Looks like I need a splitter of some sort. I need to read more I think :nerd:


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## buddf (Jun 20, 2006)

Has anyone ever considered that the distance is larger due to the fact maybe there is a delay in response time by the sub? I would be very curious to see if a sealed sub is positioned closer to its actual position than a ported sub. Supposedly sealed subs have better response times.

I remember reading somewhere that ported subs have a slight delay. I definitely do not have the equipment to test such a thing but maybe the auto equalization features are telling us just that...giving a relative position rather than actual.


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