Calibrating the 3-HO

[spfrancis]

I was curious what the best way to calibrate my 3-HO? I guess the consensus will be for me to get a SPL meter? I don't think I have the proper listening skills to really do it by ear. Is there a link on how to set by this method, or is it pretty simple? I am torn by putting my sub behind my second row sofa? The one question I have, if I do that is how much space must I leave between it and the couch/wall? It looks from another thread like It can be touching on the one side, and maybe 1" from the wall? Does that make sense? My backrow platform area maybe a little tight with 19" taken away for the sub? Maybe it is time for a narrower sofa... :) I'm going to try it up there, and see how much push back I get from the wife. My Denon receiver has the auto-setup mode(with the microphone), is that an acceptable way to set it up, or will it not do justice too the Hsu?

Thanks.
Sony

[Maximo]

This should do the trick: http://av123forum.com/showthread.php?s=&threadid=3418

[spfrancis]

hey thanks.

[cyberbri]

Bossobass's methods are great, but are pretty advanced and have a steep learning curve.

The easiest way to calibrate is to get an SPL meter and the Avia setup disc. The whole calibration method is explained on the DVD.


My basic regimen, using Avia and an SPL meter, goes something like this:

1) Experiment with sub placement, using Avia's LFE Sweep to test sub response only. Move sub around until I find the flattest response (least amount of variation in volume as frequency changes). Even a movement of 3-6" can make a huge difference, both with regards to sub placement and mic placement/listening position.

2) Level-match with mains using per-channel sub tones on Avia (the flatter the sub's frequency response is, the easier it is to set the level because it doesn't jump around as much)

3) Tweak crossover setting and phase for left and right channels. Start with 0-degree phase and 80Hz crossover, run frequency sweep for left/right channel, note amount of variation (dips around crossover point and below). Switch phase setting on sub, run sweep again. Note which gives best response. Repeat for other speaker. If response is off in crossover point range, try another point (ie., 70, 90, or 100Hz) and re-do tests.

4) Verify level-match with new settings.

5) Repeat process from sub placement if results not satisfactory.

A $3K sub in an acoustically-bad spot in a room can sound boomy and horrible, while a $300 sub in a good spot in the same room can sound much smoother and more musical. Especially with bass, room acoustics and placement play a much more significant role in how a sub sounds, much more so than tiny (or even big) variations in quality between two subs.

If no matter what, you can't get satisfactory bass response (fairly flat FR), then it's time to look into some room treatments (bass traps), and/or PEQ, like the $100 BFD (Behringer(sp?) Feedback Destroyer), to flatten out the response. I have both, and the improvement was astonishing adding just the bass traps - taking it to the next level. Adding the BFD and eqing the sub took my VTF-3 to the next level after that.

[Maximo]

The Avia disc is very helpful too. Most stores sell them for almost $50, but it can be found for much less. I thought Bossobass's explanation was fairly easy to understand compared to just doing research through the net. But, the Avia disc can help in many other areas in addition to helping you calibrate your sub.

[DNelms]

Sony-


Did any of these methods work out for you? I have tried several differnt set up methods and it seems they all seem to give slightly different results.

I have also heard the with the AVIA disc you have to realy be sure the polarity is set correctly because there is no LFE (.1) output, it is all based on the bass mamagement in your receiver.

Also, does your receiver have any THX settings such as Room Boundry Gain or some other type of bass EQ adjustments. These can also change the set-up.

Anyway, half the fun (frustration) of this hobby is the experimentation and tweaking of the system to get it just right.

Dave