Can I put my Center Channel XO in my Towers? (1 Viewer)

[Brett DiMichele]

Okay before you say NO listen to what I have to say

My Center channel is THE EXACT same C-T-C MTM with all
drivers mounted flush with the baffel and the baffel is
the same size as my towers.. Everything is exactly identical..

But..... The crossover in my Center lowpasses the mids at
70Hz. The XO in my mains Lowpasses the Mids at 100hz..

My mains take over from 100 down with the 10" subs..

My center sounds more impactful.. Because it's playing
lower..

So could I take my center channel's XO and write down the
ingreedients and build a pair of XO's for my mains with
GOOD parts on boards.. And lowpass the mids at 70Hz and
just do away with the crossover for the subs period since
my sub amp has a variable XO from 120 down to 40..

The simple answer should be "Yep" right?

I can't see any reason not to.. The mids have tons of
excursion and in thier curent configuration they don't
even move... (well they don't move much..)

 

[Brett DiMichele]

Hmmm...

Brian pointed out about baffle step compensation.. Valid
point.. I just wonder if they factored it in.. Or did they
just use the same compensation as the vertical orientation.

Damn these blasted complimacated things!

Ahh who knows..

 

[Dan Wesnor]

The center would have less baffle step compensation, which would mean less LF output lost to 4PI space, which means more total output from the same swept volume. That's why they are cut off lower.

If you do this, you will need to shove the mains back against the walls to keep them from sounding thin and weak.

Take the center and put it on a stand where one of the mains is to get an idea of what you're in for.

 

[Brett DiMichele]

Dan I already did that..

I stood the center channel up where one of my mains sits
and it sounded fantastic. Much more dynamics, more midrange
punchiness etc..

No loss of imaging or any negative effects.. Go figure?

 

[Brett DiMichele]

The only thing I can think is that the center channel has
a built in mounting bracket that allows it to be placed as
a Vertical M-T-M. I wonder if the Baffel Step is factored in
as Vertical because of this...

I don't know..

My biggest gripe is that my mains mids lowpass at 100Hz like
I previously stated, and from there down they depend on the
10's to make the rest. It seems to me that the better setup
would be to have the mids lowpassed at 70 or 80Hz and run
the 10's from there down.... That would make better use of
the drivers for thier intended tasks I would think. Why run
a pair of 10's up to 100Hz when dual 5.25" Mids can do 70Hz
without breaking a sweat.

I am going to do some tinkering.. It doesn't hurt to experiment.

I will take the stock crossovers and put them aside somwhere
and fab up some experimental crossovers cheaply and if I
like what they do for the sound I can always do a good pair
with better parts.

And then I can run my 10's directly off my external amp.
Right now I have cascading crossovers since the sub's are
already highpassed at 100Hz and the sub amp has a variable
xo that I have been running at 120Hz.

 

[Chris Tsutsui]

What I don't get is why would the baffle step be an issue if the enclosures and drivers are identical.

The only thing separating them apart is the center has a different crossover point and can be tilted on its side. Do those factors affect the baffle step compensation?

 

[Patrick Sun]

I'd be more concerned about whether AR actually went for accounting for the lobing for a sideways MTM (usually 3rd order slopes are used for this configuration) used as a Center channel speaker, vs. their upright MTM front speakers, whose XOs may have different XO slopes to account for the vertical lobing patterns for their intended use.

 

[Brett DiMichele]

Is there any way to check and see if they took baffel step
or lobing into account?

I had another idea though.

I can take the stock XO's out and bag them. Build 2 new
crossover boards based on the originals but lower the mid
range lowpass that's the only thing I want to change. Plus
I want to eliminate the subwoofer's section of the XO
entirely since I have an external variable crossover for
the subs.

That way I won't have to worry about circumventing any
baffel step that may be built in. Just lower the lowpass
for the mids. Wouldn't that work?

 

[Todd Shore]

Active outboard crossover? What slope? Are you then going to bi-amp? You'll probably be changing the roll-offs on your 10's and 5.5(?)'s.

I would look at the existing highpass to the 10's and see what slope it is using. Going up in order (say to 4th order active from a 2nd order passive) will cause a dip at the crossover.

Have you measured for in-room bass response? Doing do will tell you where you need to cut or boost. Centering that dip on a room mode is a simple tune. Really tightens things up.

There should be enough people here that can help you analyze the existing passive crossover. If not here, then other people to talk to at other places like MAD.

 

[Dan Wesnor]

Baffle step is different for center channels because they typically sit on the TV, effectively extending the baffle. At least it should be different, some designers don't put enough baffle step on their mains.

To compare the tone difference, switch between speakers with pink noise, like that found on Avia audio setup tracks.

 

[Ryan T]

Baffle step is different for center channels because they typically sit on the TV, effectively extending the baffle.

I have a quick question about baffle step compensation. I built a pair of GR-Research AV 1's. They are designed to be bookshelf speakers but i made them into towers with false bottoms. Would that have an effect on the sound since I extended the baffle all the way to the floor? I know this is kinda off topic but if any one could help me out on this I would appreciate it.



Thanks,
Ryan

 

[Brett DiMichele]

Todd,

They are BiAmped already. The external crossover for the
subs is built into the sub amp it's variable from 40 to
120.


As long as I take the stock passive crossover design and
just lower the lowpass on the mids what issues will I have
then? I shouldn't be circumventing any baffle step.

I hear people bragging up Marchand active crossovers all
the time. They look interesting but if people here are so
dead set on Baffle Step Compensation, how do you apply that
with something like the Marchand Actives??????

Just curious..

 

[Todd Shore]

You can integrate it into the circuit or use really large baffles. You can also use the room and your bass enclosure tunings to tune for flat response by overlaying peaks and dips.