So quick question

[Rdmarsiii]

Granted maybe I'm just thinking too far into this, but what is the deal with Audyssey (sp?) and timing and what not? I have the THX Ultra2 system with four of the subs, and everything sounds more than perfect to me, but a few people have asked if I've "calibrated" it. Well, no. I don't have the first clue on what that includes, so can anyone enlighten me? Is it worth the trouble? Or, rather, will I even notice a difference?

This is in the sub section because of possible phasing issues with the four subwoofers =P

[Chris A]

Audyssey does a couple of things pretty well via an automated series of tests using their supplied microphone, resulting in calibration settings on your AVP/AVR:

1) time alignment of your speakers with respect to your prime listening positions to compensate for differing speaker distances and other built-in delays of the speakers around you (this is important and effective)

2) SPL calibration of the speakers around you.

The third function that Audyssey tries to do is EQ of each channel. In my setup/version of Audyssey this function doesn't work well, so I turn that particular feature off.

To your question:

...so can anyone enlighten me? Is it worth the trouble? Or, rather, will I even notice a difference?

Answer: yes.

The first two calibration functions discussed above are extremely important. You will hear a much more crisp and focused sound image around you when you calibrate the full-range speaker time delays around your listening position. Additionally, your subwoofers [i'm assuming these are direct-radiator subs...] will gain from being time-aligned to your other full-range speakers, but the time-alignment requirements for your subs are much less critical than your other full-range speakers to each other due to the low frequency wavelengths involved (in fact, they are ~1/10th to 1/100th as sensitive at their crossover point to the mains than the mains are to each other...)

The second function is SPL setting (amplifier channel level calibration) for each of your full-range speakers and your subs. Audyssey also does a nice job of level matching the SPL of each channel to within 1/2 dB at your listening positions (averaging several listening positions that you choose in your room). This is something that is difficult to do well using just your ears, especially when trying to calibrate your subs to your full-range speakers, and your surrounds to your fronts if they are different types of speakers (i.e., timbre differences between speakers). The effect of this calibration is also ear-opening once it's done.

Chris

[StephenM]

I'll disagree with Cask on the importance of the equalization (not your standard parametric eq but FIR filters with thousands of points) which helps even out the response in the room; it will take measurements at numerous points to give the most even response. With 4 subwoofers, I think you'd have to ask Audyssey about which product to use; I was about to recommend the SVS AS-EQ1 (developed with Audyssey), but even it only corrects for 2 subs.

[Rdmarsiii]

So what are my options? I do agree that everything should work in compliance with each other, but then again, I still don't know how to get to that point, much less if my Sunfire TGP-V allows me to do such options.

[Chris A]

So what are my options? I do agree that everything should work in compliance with each other, but then again, I still don't know how to get to that point, much less if my Sunfire TGP-V allows me to do such options.

I'm assuming that you might not have gone through the procedures shown below, so forgive me if I am covering subjects that you've already addressed:

I found the owner's manual to your unit at http://www.sunfire.com/downloads_archive.asp. Pages 38-40 shows the menus and walks through the setup procedure for setting channel delays (distance from your listening position) and channel SPL level calibration.

The distance from your prime listening position to each speaker should be measured with a tape measure to the nearest 1/2 inch (yes: the nearest 1/2 inch is really needed). Plug those numbers in the table shown at the bottom of page 39 on your unit.

You can get very close on the SPL calibration using the procedure on page 40. I'd first turn the gain down low fairly low (if the receiver lets you do this) to set all channels (the ear is most sensitive at lower levels to relative loudness), then turn it up fairly high to hear any differences once you've finished setting the channel gains. This technique will get you to within one dB or so, especially if all your speakers are similar in timbre (as I understand they are in your particular case).

Speaker size and EQ setups is something that you can also get from the manual. I'd play around with these settings and listen to the results. You should be close enough using these methods.

The advantage of having and using Odyssey to do these tasks for you with a supplied microphone is that it can handle timbre differences in speaker-to-speaker settings a little better than manual setting of SPL levels.

But the biggest advantage of Odyssey for me is in setting speaker distances (delays). In my case, I have three different full-range horn-loaded speakers (Jubilees, Belle, subwoofers), that require the path length addition of the horns to the distance settings, Additionally, I'm using three different electronic crossovers that have their own minimum delays that also have to be accounted for in the distance settings. For the subwoofers alone (their path length is 21 feet...plus the DSP electronic crossover delay in the Crown XTi-1000 adds to the total delay settings. Odyssey does all this for me.

For the EQ in my setup, the solution that I use is a Behringer DEQ2496 that I bought a number of years ago that I use only to calibrate the EQ in each channel when I set up my system. I used a calibrated microphone (Behringer ECM-8000) using the continuous pink-noise generator in the DEQ2496 to adjust. Then I switched the microphone to connect to a laptop via an interface mixer, with the laptop running Room EQ Wizard (REW) to iteratively check the EQ settings arrived at my the DEQ2496. After I got everything leveled out - I transferred the EQ settings to the electronic crossovers and the XTi amplifiers for the subs. I then checked the settings using the REW/laptop/calibrated mike once again. The results spoke for themselves. The dark green line is the resultant room response at my listening position. The light green line is Jubilee response un-EQed, and the red line is the subwoofer response un-EQed.

Chris

[Fish]

Four subs? are these subs any good or do you have several thousand sq ft of space to fill?

[Chris A]

Four subs? are these subs any good or do you have several thousand sq ft of space to fill?

I assume that you haven't read Floyd Toole's articles on the use of multiple subs:

http://www.harman.com/EN-US/OurCompany/Technologyleadership/Documents/White%20Papers/multsubs.pdf

http://www.harman.com/EN-US/OurCompany/Technologyleadership/Documents/White%20Papers/LoudspeakersandRoomsPt3.pdf

Using multiple subs isn't as esoteric as you imply. []

Chris

[Chris A]

Here is yet another approach to addressing the same problem, albeit a much more intriguing one...the double bass array (DBA) technique.

Chris

Edited April 15, 2014 by Chris A

[Lightguy]

I have formulated an equation explaining Subwoofer efficiency;

1 big *** sub > 3 or 4 wimpy subs.

Do the math.

[StephenM]

So what are my options? I do agree that everything should work in compliance with each other, but then again, I still don't know how to get to that point, much less if my Sunfire TGP-V allows me to do such options.

As far as Audyssey goes, the only thing I can think of would be using the SVS/comparable Audyssey products, you could use a Y cable on each of the two outputs, and utilize the four subs in two stacked pairs. Otherwise, I would again reiterate talking to Chris K. at the Audyssey forums. He's very helpful and reasonably prompt in his replies.

[Rdmarsiii]

I have formulated an equation explaining Subwoofer efficiency;

1 big *** sub > 3 or 4 wimpy subs.

Do the math.

Umm, these subs are not wimpy by any means, sir.

[Rdmarsiii]

So what are my options? I do agree that everything should work in compliance with each other, but then again, I still don't know how to get to that point, much less if my Sunfire TGP-V allows me to do such options.

As far as Audyssey goes, the only thing I can think of would be using the SVS/comparable Audyssey products, you could use a Y cable on each of the two outputs, and utilize the four subs in two stacked pairs. Otherwise, I would again reiterate talking to Chris K. at the Audyssey forums. He's very helpful and reasonably prompt in his replies.

The Sunfire has three subwoofer outputs, so I believe I'm fairly good on that end. Plus, each amp has their inputs/pass-throughs. I will get ahold of Chris though! Thanks.