Subwoofer set-up using Audyssey Room Correction.

[JerryMeeker]

The following procedure was used to calibrate Hsu ULS-15 Dual-Drive subwoofers using a Denon 4308CI AVR with Audyssey MultEqXt room equalization. Since subwoofer configuration generates a lot of different opinions, feedback regarding this procedure would be appreciated.

Step 1: Subwoofer placement. Make sure that the distance from each sub to the primary listening spot is exactly the same. This is because Audyssey calculates distance for only one subwoofer, and if the distance to the two subwoofers is significantly different, the sub delay setting will not produce optimal results. (Unfortunately, this places a severe restriction on where the subs can be placed in most listening rooms. Many experts recommend moving the subs around to achieve the best bass response, but it two subs are used, Audyssey calibration will not be optimal unless the subs are exactly the same distance from the listener.)

Step 2: Setting the subwoofer levels. Since the acoustic characteristics of the room are likely to be somewhat different for each of the subwoofers because they are in different locations, it’s important to set the volume level for each subwoofer to achieve roughly the same volume at the primary listening spot. This is accomplished as follows:
1. Place a Radio Shack sound pressure meter at the primary listening spot.
2. In the AV receiver setup menu, select Speaker Config/Channel Level, and generate a tone for the subwoofer.
3. Adjust the audio output levels on each subwoofer to achieve the same level at the primary listening spot, as shown on the SPL.
Note: at this point we don’t know if the volume levels on the subs are the correct levels-we only know that the settings produce a balanced output. The next step will determine if the volume settings are too high, too low, or just right.

Step 3: Using Audyssey to determine the initial subwoofer volume setting. Do the following:
1. Run the Audyssey calibration with the microphone in the primary listening spot.
2. After one iteration of the test tones, go ahead and select “calculate”.
3. After the calculation completes, examine the resulting speaker levels.
4. Note the level setting for the subwoofer. If the setting reduces the subwoofer output over 5db (e.g. -8db or -9db), then the subwoofer volume setting is too high. If the setting boosts the subwoofer output by more than 5db (e.g. +8db or +9db), then the subwoofer volume is set too low. The ideal result is to have Audyssey set the subwoofer volume in the +/- 1db to 2db range. Why? Because this allows the greatest flexibility to tweak the subwoofer levels after the Audyssey calibration has completed.
5. If the level setting is too high or too low, cancel the Audyssey calibration, and repeat Steps 2 and 3 until the subwoofer level falls into the +/- 1db to 2db range.

Step 3: Complete the Audyssey calibration. Make sure to use all eight microphone positions!

Step 4: Inspect the resulting speaker configurations after the calibration has completed and make any changes according to your preferences.
1. It is recommended to set all speakers to “small”.
2. Adjust the crossover frequencies for each speaker according to your preferences (e.g. 80 Hz). This does not affect the Audyssey calibration.
3. Set the Audyssey Dynamic Volume for each input according to your preference (e.g. Dynamic Volume “on”, setting “Day”).

Step 5: Test the results! You should hear tight bass integrated seamlessly with your other speakers.

[Pete_Hsu]

Hi Jerry,

Those setup instructions seem pretty reasonable. The one thing that is debateable is about level matching two subwoofers (ie. set each subwoofer's volume knob so that SPL level is equal at the listening position at a given frequency, with each subwoofer measured in their final separated position in-room), as opposed to gain matching two subwoofers (ie. set each subwoofer's volume knob so that SPL level is equal at the listening position at a given frequency, with each subwoofer measured in the exact same position in-room). Provided that any one subwoofer does not run out of steam, then level matching is fine, but the best way to maximize headroom is to gain match.

Sincerely,

[totoro]

Was wondering about what, if any, special settings or procedures I needed to do to my new VTF-2 MK3 in preparation for running Audyssey? Just got my new Onkyo 5507 pre/pro and was about to try this for the first time and thought I would ask just in case. thanks so much.

[JerryMeeker]

While Pete is the expert, I want to share some thoughts. Since receiving my ULS-15 Dual-Drive several weeks ago, I have done quite a bit of experimenting, and have run Audyssey multiple times looking for the right settings.

From my perspective, the most important thing to remember is that Audyssey is the LAST thing you do in your configuration. Everything else (placement, level settings, settings on the back of the sub) should be done before running Audyssey. And, if any of these changes, then you must re-run Audyssey.

The first consideration is placement of the sub. There is a wealth of information on sub placement—do the research. From your posting, I believe you have one sub. For those of us with two (or four) subs, placement can be tricky, because Audyssey requires that the subs be placed at the same distance from the primary listening point. With one sub, simply experiment with the best placement to achieve the best sound according to your tastes. Once the sub is in place, take an accurate measurement of the distance from the center of the sub speaker to the primary listening point (at ear level)—you will compare this actual distance with the Audyssey-calculated result later.

The next consideration is the level setting on the sub. See my original posting—start at somewhere between 10 and 12 o’clock, run Audyssey, check the boost or trim that Audyssey assigns, and repeat the process until the Audyssey setting is in the +/- 3 db range.

The final consideration is the adjustments on the back of the sub. I would leave the phase setting at 0, and the crossover switch to “off” (i.e. adjust crossover settings in the AVR).

Now you are ready to run Audyssey. Follow the instructions in the Audyssey setup guide here (http://www.avsforum.com/avs-vb/showthread.php?t=795421 (http://www.avsforum.com/avs-vb/showthread.php?t=795421)). Make absolutely sure that your listening room is dead silent (I even turn off the DVR’s in my equipment rack so the fan and hard drive noise doesn’t affect the calibration). Turn of the heater/AC blower as well. Make sure you measure all the listening points (e.g. 8 measurement points), and make sure the microphone is exactly at ear level.

Once Audyssey has finished, make several post-calibration adjustments: it is recommended to set all speakers to “small” for the best bass management, for example. And set the LFE low-pass filter to 120 Hz if it isn’t there already. You can also adjust crossover settings upwards from the Audyssey settings if you feel it is necessary, but do not adjust the crossover settings lower than the Audyssey results.

Check your calculated sub distance? Is it accurate? Three situations could exist; the calculated distance could be larger than the actual distance, close to exact, or smaller. If exact, great. If larger, a number of factors could be causing this—read the Audyssey Guide. Do not adjust the calculated distance.

If the calculated distance is smaller, this is a trickier answer. Based on what I have read, the appropriate response is to adjust the setting upwards until it matches the actual distance. Audyssey describes several possible causes of this result. My ULS-15’s consistently result in a calculated distance approximately one foot closer than the actual distance, yet none of the causes mentioned by Audyssey seem to apply. I manually adjusted the distance, and the resulting tightness and clarity of the bass is improved.

Now the fun part—listen to the results. If something doesn’t sound quite right, keep trying until you are satisfied. And remember, if you change the sub placement, level setting, etc., you need to re-run Audyssey. Good luck!