Axiom Home Page Forums General Discussion Technical Questions Using an SPL Meter

Martin, if you have a receiver such as the 3808 or the many other units that have auto calibration systems, then no, in my view there's no good reason to do the calibration manually. The auto calibration done with the receiver's built-in SPL meter and processor should be at least as accurate as using a separate external SPL meter to assist in making a manual calibration. The added factor of human error in the manual calibration would make it likely that any difference in the results would mean that it was us, not the receiver, that was "off".

This doesn't mean that an SPL meter isn't useful, and I frequently use my RS digital SPL meter to check minimum, average and maximum sound levels when I play various program materials.

Ok, but it is possible to let the 3808 just calibrate the distance and level, and not apply any equalizer?

For example when using pure direct button, I would assume that nothing at all is applied? But this mode only supports stereo correct?

Correct, and yes, it should be kept in mind that Audyssey and the other calibration/room equalization systems do have those two entirely separate functions. The calibration can be used and not the room equalization.

On the Audyssey equalization function itself, however, I recently read the current issue of The $ensible Sound magazine, in which David Rich ran very extensive tests on the Onkyo 705 and 805, including the Audyssey equalization. In addition to praising them in general for their excellence as amplifiers, Dr. Rich's graphs and listening tests relating to MultEQ XT led him to comment that "The excellent flattening of room effects in the 100Hz-500Hz region improves sound quality for any speaker" It's something that calls for careful experimentation.

So the recommended setup is to run the auto calibration and leave it with that as it should generate the best response and sound?
Im planning to buy the 3808 soon, but Im still trying to figure out some stuff about it.
For example how it works with SACD DSD signal over HDMI. Some say that it must convert to PCM if you want to use Audyssey/MultEQ. Also Im trying to figure out what all the EQ modes like cinema and so on are really doing opposed to just running the normal dd/dts modes.

No, that certainly wouldn't be my recommendation. With the 3808 and other receivers which use Audyssey MultEQ XT, it's a major feature(and expense item)of the unit, so part of its function shouldn't be simply discarded. Initially, maybe just the calibration can be done, but the room equalization should then be given a thorough test later on. Dr. Rich's tests and the reports of many users indicate that benefits are to be had.

I thought that was what I wrote. Im not sure exactly how this works, but I thought you just run the calibration and then the reciever sets everything up for you including EQ etc...
Also I just wondered, how do you set the volume knob on the sub before calibrating?
And what volume should you turn up to on the reciever when using a SPL meter?

If you use the auto setup and run audyssey then the denon will automatically adjust channel levels during the set up... there is no need to touch the volume knob.

If you manually calibrate then just adjust the channel levels and not the main volume as well. I left the main volume at 0 db (its default posistion in the manual setup menu for the denon) during the entire manual set up and just adjusted the individual channel levels.

I would highly recommend enabling Audyssey. Have a look at this thread over at AVS: http://www.avsforum.com/avs-vb/showthread.php?t=795421

I have the Onkyo 705 and really like the difference Audyssey makes in my room.

definitately give it a try. I tried it out and found that I like things better without it... May give it another shot later on in the future though.

I think using an SPL meter gives the system that little personal touch, and knowing that it is setup to the best it can be is a great feeling.