[Rob Babcock]

I agree that 0.2 dB would be great, but I don't think most of us would have much luck achieving it.  Firstly, the Denon DVD-2200 doesn't give you anything like that fine of control, and neither will most rec's/prepros.  Secondly, most of us don't have access to an SPL meter that good.

Of course changing the distance will affect the volume, but then you need to adjust the ch delay, and (suprise! ) the Denon doesn't allow finer than 1 ft adjustment for that. (And it dsn't function with SACD... ).

That said, I wholeheartedly agree with you, Dan, that calibration is crucial.  I would like to get mine calibrated to the degree that you suggest, but I'm just a frozen caveman audiophool!

[John Casler]

I agree that 0.2 dB would be great, but I don't think most of us would have much luck achieving it. Firstly, the Denon DVD-2200 doesn't give you anything like that fine of control, and neither will most rec's/prepros. Secondly, most of us don't have access to an SPL meter that good.

Thanks Rob, that's exactly what I was trying to say.  None of my equipment has that kind of ability.

In fact, Dan called me personally (thanks Dan) and we discussed that there are only maybe 3 preamps that do.  That said, most of the time that type of "trimming" would (as you state) be done with the DVD player and I don't know of any consumer grade model that has that capability.

Does anyone?

Rob, did you find any way to "pause" the test tones?  So that you could make a "finer", more precise adjustment?

I found it virtually impossible to make the adjustment, and get a reading, before the channel changed.

[Dan Banquer]

Well I think we are getting to the root of this problem. John C; I'll bet Rob Babcock can give you recommendations on some good test discs for calibration. Another alternative is to get a pink noise generator. I think Rat Shack makes one. What a lot of the pro guys use is an RTA analyzer. If you can borrow one of those for a few hours that would be the best alternative. If I remember correctly Rat Shack also has a digital spl meter with readings down to the first decimal point. I have no idea if this at all accurate.
Most of consumer equipment will not give the capability of calibrating level control down to 0.2db. DVD players are typically less refined in this area than processors. John C; you have your work cut out for you. However once you get a close control on level you will find the need for equalization to decrease also, and that holds true for stereo as well as multichannel.
             d.b.

[Rob Babcock]

I'm still wrestling with the issue of a test disc.  So far I'm not aware of any DVD-A or SACD of test tones (anyone who knows of one, chime in please!), so Avia will still have to do for now, along with the Stereophile discs.  Yeah, the latter are just stereo.

Worse yet, the internal test tones don't seem to be accurate (by what I've read).  There's some discussion on Audioholics.com about the difficulties the staff had with the test tones for calibration.

I still do need to do some tweaking, and I'm very much learning as I go.  That's SOP for MC fans, I'm afraid!   The rulebook is pretty thin and the ink is still wet!

[John Casler]

I did find the "manual" mode so I can pause the test tone on each channel for as long as I like and adjust it "much" more precisely.

I also rearranged the speakers to "all" be exactly 9 feet from the sweet seat.  It is very close to wearing head(speaker)phones.

[Dan Banquer]

Is that good or bad John? or just different.

[John Casler]

Well I think we are getting to the root of this problem.

Dan, I have never stated I had a problem other than finding the manual setting on the DVDplayer test tones.

Is that good or bad John?

From what I hear it is very good.

While it is fun to advise people to go out and search for esoteric test equipment, I, for one, would find it interesting to know what "your" multichannel system consists of, and how you have acheived the accuracy that you (for some reason) feel I need.

I would be particularly interested in the brand and model of:

1) your DVD player
2) Your processor
3) Your sound Pressure Meter
4) Brand and type of speakers
5) Are all 5 speakers the exact same model and drivers

Do you trim your channels with your DVD player or the Pre/Pro?

Do you use, a special DVDA/SACD that has specific white noise/test tones?  Or do you use the DVD players internal tones?

I would also like to know your general room, and speaker distances and whether you use the standard ITU?

How close are your surrounds to the wall?  Or are they "off the wall" like your frontal array?

What software have you found that best displays the potential of this multichannel music process, and what specific deleterious affects have you found from "not" trimming all channels to .2 db?

From your comments, you must have much experience and one incredible system.


Thanks in advance, for the info.

[Dan Banquer]

A good spl meter is not esoteric. Most decent DVD/ DVD-A/ SACD players have excellent uniformity on all their channels. Most that I have tested are well within 0.1 db from Channel to Channel. Most pre processors only have a level trim of 0.5 db accuracy which is a problem. The RTA is something I borrow from a speaker designer friend of mine when I need it.
In short John; esoterica is not a major criteria here, nor is my system. Level accuracy, equidistant spacing, and acoustic treatment will make a multi channel system work to it's maximum. Those three things are the most important to goals to work for. That's really common sense if you think about it for a moment. I would say more but as a manufacturer I am limited due to the rules of these forums.
              d.b.

[Marbles]

Dan,

He asked the question on what your equipment is....I assume it's your own stuff.  Feel free to post about it in this thread since he asked, or answer it in Market square if your more comfortable answering there.