Simple Level Matching

[Alex2507]

Here's my dilemma:
I have a Rives disc, an Avia II disc, two subs and an EQ. I'm not sure if I should level match the subs to the
L & R channels with the Avia or level match the subs with the Rives disc to produce a flat response.

Here's my question put a different way:
Should I be trying to get a flat response using just one channel and the subs or using both channels and the subs.

Note: The two subs are running off of one sub pre-out so it's a 2.1 rig.

TIA

 

[bpape]

2 subs can be great - but they'll take more effort and tweaking of position to get them to work properly. How I set up 2 subs:

Work with positioning of the first sub to get the flattest response.

Work with speaker positioning to get the best response

Adjust xover and phase to blend the best you can. Tweak sub positioning as required to deal with the xover frequency overlap.

Bring in the 2nd sub and adjust position and phase and level to both blend with the existing 2.1 system and also attempt to fix any anomolies remaining after just 2 speakers and 1 sub.

This can be a long drawn out process but if you spend the time, the results can be outstanding.

Bryan

 

[Adam]

I haven't tried running both of my subs, yet, so I don't have personal experience with it. If you haven't read it already, I'd like to point out (probably just a reminder to you) one of the articles on the main AH site under "Tips & Tricks / Get Good Bass". They have a nice article on setting up multiple subwoofers at this link here.

 

[jostenmeat]

2 subs can be great - but they'll take more effort and tweaking of position to get them to work properly. How I set up 2 subs:

Work with positioning of the first sub to get the flattest response.

Work with speaker positioning to get the best response

Adjust xover and phase to blend the best you can. Tweak sub positioning as required to deal with the xover frequency overlap.

Bring in the 2nd sub and adjust position and phase and level to both blend with the existing 2.1 system and also attempt to fix any anomolies remaining after just 2 speakers and 1 sub.

This can be a long drawn out process but if you spend the time, the results can be outstanding.

Bryan

Nice post, Bryan.

I would love to hear more details (of any sort) on what happened . . . did you try dramatically different positions? I typically always read about subs at opposing midwall points, or both up front.

How often do you find dual subs with more "strange" configurations? Say, for example, something like one sidewall + rear wall?

I remember reading Savant's idea of putting one of the subs at a different height!

Just curious for your 2 cents. I have one sub, and it'll be like that as far as I can tell . . . but ya never know!

 

[mtrycrafts]

Here's my dilemma:
I have a Rives disc, an Avia II disc, two subs and an EQ. I'm not sure if I should level match the subs to the
L & R channels with the Avia or level match the subs with the Rives disc to produce a flat response.

Here's my question put a different way:
Should I be trying to get a flat response using just one channel and the subs or using both channels and the subs.

Note: The two subs are running off of one sub pre-out so it's a 2.1 rig.

TIA

While the 2 subs are off the one output, their position in the room will certainly affect their response that you are after where you are sitting.
If you flatten the response on one, then the other, you can bet when both are running, it will not be flat anymore. It is a back and forth smoothing of the curves.
Then, the overall level matching is to the level the other speakers are at, or some boost for personal taste.

It is not an easy proposition to flatten two subs that are in different positions. Speaking form on hand experience

 

[Alex2507]

The article Adam linked says to #1 point your SPL up. The Rives disc says to point it at the source.

I'm having trouble wording my real question because of some fundamental confusion about rec'r x-over affecting both channels and doubling amplification when 2 channels are going. Arghhhh ... To make matters worse now I gotta fold laundry!

Their is a really old article/thread about x-over frequencies and bass management that somebody revived a few months ago. There was some excitement because somebody thought that a particular member was posting again. I'd like to read that again if someone can find it.

Now it's off to domesticity.

 

[Alex2507]

Now that I know what my question is, I have the answer too.

I was disconnecting my speaker to plot a graph for one channel. That means that everything below the receiver's x-over for the disconnected speaker still got put out of the subs creating a boost below 80Hz on the graph. That's where I was befudled. The solution to that is to disconnect the output stage of my EQ. That eliminates one channel completely from the graph.

Note: Disconnecting an output stage as opposed tto the input stage is better because you don't have a live wire laying about.