How many subs should I get?

MichaelJ

Originally posted by Dr. Spec
Hi Mike:

There is a difference between balancing all the speaker levels (which can be done at any volume for the test tones), and calibrating to Reference Level (which must be done at either 75 dB or 85 dB depending on the specific disc).

The whole point of calibrating a system to Reference Level is that it (or any level below it) would be the same volume in any room for any given DVD scene. It is a universal benchmark by which we can all experience the same playback level.

The fact that I use Master Volume 00 is not relevant, it is only for convenience. I could use any combination of Master Volume and individual speaker levels (which on my Denon go from -12 to +12) to achieve 85 dB on the Avia test tones.

But since I DO use Master Volume 00, my individual speaker level settings required to hit 85 dB on the test tones in MY room all end up in the +2 to +5 range.

In a smaller room, I wouldn't need them that high to hit 85 dB on the tones - maybe in the -3 to 0 range.

In a larger room, I might have to wick them up to the +5 to +8 range to hit 85 dB.

See what I'm getting at? The calibration level is always the same - what varies from room to room is the amount of power required to achieve that level.

So if we both calibrate to Ref Lev in our HT rooms, if we both play LOTR at Reference Level, the playback volume in both rooms will be the same, even though the power requirements will probably be quite different.

To answer your first question - yes, it IS necessary to calibrate to Ref Lev if we are to compare notes on Master Volume settings and SPL peaks for any given scene.

To answer your second question - I usually listen at anywhere from -15 to -10 (with Reference Level being 00), depending on the DVD.

BTW, the Sauron "reverse sweep" explosion only reaches about 50 Hz at its deepest point, although it IS very loud.

The famous "ring drop" DOES extend strongly into the low 20 Hz range, and should reach almost the same exact peak volume as the Sauron explosion. If it does not, your sub is checking out early in terms of deep extension and power.

I get about 112 dB SPL peaks on both scenes at -14 Master Volume setting with the sub calibrated about 4 dB hot.

Doc

Okay Doc,
Looks like I have some additional work. I made a copy of your notes and will refer to them while calibrating my speakers. I have the Sound & Vision Ovation test disk. My Onkyo however, produces its own test signals, which I used to calibrate my speakers at 70 db. I will calibrate them at 85 db and note the output level indicators on the amp.

I do get the same output level on the ring drop as on the Sauron "reverse sweep" explosion, but the ring drop is of shorter duration.

I am still setting up my system, so value your recommendations.

I just ran wire in the walls for my surrounds. The experience made me a believer in high-quality cables. I always figured just plain lamp-cord would be all that was needed for speakers. The speakers were hung on the wall, connected with some lamp cord that had been laying around in the garage. After monitoring the forums, I decided to go with better-quality in-wall speaker wire (Monster Cable XP HP CI) and was astonished at the increase in clarity. Now, of course, I have to buy better cables for my front and center speakers.

.................... MikeJ