Hey guys, here's the situation:

I've got dual Outlaw LFM-1EXs' that I'm happy with.

They're setup near field on either side of the main listening couch. One is in a corner about 12 inches from each wall, the other is on the open end of the room/couch again about 12 inches from the rear wall. They are in ME mode.

The subs were set up following the Audyssey setup guide. Today I was running a subwoofer test tone cd to measure the response of the subs, and I noticed it seemed like I was getting a lot more chuffing out of the sub on the open side of the couch.

I ran the test tone CD first with one sub off, then the other and what I found was the sub on the open end of the couch was indeed chuffing a lot more than the one in the corner at the same test tones, I would say this is because it was meauring signifcantly louder as well according to my RS meter, about 8 deicbels louder at the 16 HZ tone.

So my questions are:

1) Why should this be? Is this simply my room response in practice, or do I have an issue with one of the subs?

1) Should I calibrate the subs to be equal according to the test signal from the AVR, or should I calibrate them to be equal according to the test tone cd?

Any ideas/help is greatly appreciated!!

How do you calibrate the subs' relative levels, now? Do you level-match them? What is ME mode? How does the Audyssey guide say to calibrate 2 subs?

How do you calibrate the subs' relative levels, now? Do you level-match them? What is ME mode? How does the Audyssey guide say to calibrate 2 subs?

Thanks for the reply.

ME = maximum extension, one port plugged.

I calibrated each seperately to 80 Db on the RS meter using the AVR test tone, one on, one off, then repeated the process with the other and ran audyssey with both subs on.

Measure their output individually nearfield. Just because they're both playing 80dB on the meter from a given listening position doesn't mean they're actually set at the same level. The corner loaded sub will have to work less to get the 80dB, whereas the open end unit will work harder, thus show signs of chuffing or port noise sooner. Also, with test tones, port noise will be much more noticable as it's a single note without any other notes or noises to cover the wind noise up.

Measure their output individually nearfield. Just because they're both playing 80dB on the meter from a given listening position doesn't mean they're actually set at the same level. The corner loaded sub will have to work less to get the 80dB, whereas the open end unit will work harder, thus show signs of chuffing or port noise sooner. Also, with test tones, port noise will be much more noticable as it's a single note without any other notes or noises to cover the wind noise up.
Thanks, this makes sense.

Any other advice?

I calibrated each seperately to 80 Db on the RS meter using the AVR test tone, one on, one off, then repeated the process with the other and ran audyssey with both subs on.So, essentially, your subs ARE level-matched. They are each contributing equally (prior to EQ, anyway) to the overall SPL at your sweet spot. But because of the room (and maybe their relative distances to your sweet spot), they are not running at the same exact gains. Another way to implement both subs is to run them at the same exact gain.

You may want to read these two threads regarding integrating dual subs. Both these threads were going, essentially, at the same time, and some of the info is redundant.

http://www.avsforum.com/avs-vb/showthread.php?t=1068195

Starting at Post#59.

http://www.avsforum.com/avs-vb/showthread.php?p=14990671

Starting at Post#7. Ricci's Post#23 is also useful.


There has also been some very recent discussion of the same subject in this more recent thread, starting (most recently) near the end at Post#1799.

http://www.avsforum.com/avs-vb/showthread.php?t=1124011

So, essentially, your subs ARE level-matched. They are each contributing equally (prior to EQ, anyway) to the overall SPL at your sweet spot. But because of the room (and maybe their relative distances to your sweet spot), they are not running at the same exact gains. Another way to implement both subs is to run them at the same exact gain.

You may want to read these two threads regarding integrating dual subs. Both these threads were going, essentially, at the same time, and some of the info is redundant.

http://www.avsforum.com/avs-vb/showthread.php?t=1068195

Starting at Post#59.

http://www.avsforum.com/avs-vb/showthread.php?p=14990671

Starting at Post#7. Ricci's Post#23 is also useful.


There has also been some very recent discussion of the same subject in this more recent thread, starting (most recently) near the end at Post#1799.

http://www.avsforum.com/avs-vb/showthread.php?t=1124011Thanks for the links. I'll give those threads a read, sometimes the amount of infomation here is a little overwhelming!

EDIT: I just read Mark's post, very interesting. Obviously I was doing what you thought he meant, calibrating for SPL at the sweet spot. I'll try setting the gains to be equal.

Thanks for the links. I'll give those threads a read, sometimes the amount of infomation here is a little overwhelming!

EDIT: I just read Mark's post, very interesting. Obviously I was doing what you thought he meant, calibrating for SPL at the sweet spot. I'll try setting the gains to be equal.Yeah, I didn't understand, initially. There is level-matching, which is what most people do, and it always made sense. But Mark presented the idea of gain-matching, which also makes sense. If you look toward the end of that last thread I linked to, Nuance recently changed his subs from level-matched to gain-matched and seems pleased with the results.

Gain matching will ensure max capability out of both, not just one (as mentioned in the linked post). One drawback to this method in certain setups is if the rear sub (in a front / rear configuration) has a natural location gain due to corner or something, then with equal gain settings the rear will be "louder" (higher measured output) than the front. Some will find this odd sounding as the sound will not be anchored in the front with the mains.

Definitely test setting the subs to equal gain settings (match the dials and nearfield measure with an SPL meter on each separately) and see if the sound seems too heavy on one side (likely the corner loaded unit). However, you'll have maximum sound pressure capability in the room using the gain matching method.