Add a volume control to my center speaker? - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 19 Old 11-13-2007, 02:23 AM - Thread Starter
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Greetings-

I’m hoping to get some advice in solving a dominant center speaker issue. In my case even with the center speaker set to its lowest possible volume (in the receiver setup) it’s still just slightly too loud on some sources. Most things really and it’s just enough out of balance to be irritating.

My center speaker doesn’t have its own volume control which is what I expect I need. Can I just add a potentiometer to the + side and use that to diminish the volume? If so what would the rating/specs be? I really just need a temporary solution because I am going to replace this center and add a ‘real guy’ amp after the holidays.

Would something like this work?

The core of the problem is that my speakers are mismatched. My fronts are Magnepan MMG's (4 ohm) and my center and rears are 8 ohms. My receiver is the Panny XR50 and it drives the MMG’s very well and louder than anyone could possibly stand and sounds pretty good for ‘only’ 100watts. But the center is even louder and with the receiver controls I cannot quite diminish it enough.

Thanks for any advice!

Peace . . .

PVR user since the late 1900's . . .
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post #2 of 19 Old 11-13-2007, 04:36 AM
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Quote:
Originally Posted by tim99 View Post

The core of the problem is that my speakers are mismatched. My fronts are Magnepan MMG's (4 ohm) and my center and rears are 8 ohms.

You might want to try increasing the gain on the mains within the receiver setup. This would be in conjunction with the reduced setting for the center channel. The Maggies are a hard load on the internal amps of your receiver due to their 86dB sensitivity. And the mixed ohm speakers are making that situation worse. I think you are on the right track, getting separate amps for the Maggies. Also, might want to try adding some acoustic treatments to the room to smooth out the room modes.
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post #3 of 19 Old 11-13-2007, 04:53 AM
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Quote:
Originally Posted by ChipSmith View Post

You might want to try increasing the gain on the mains within the receiver setup.

You can't do that on the Panny. The other speakers are adjusted to the mains which are always fixed.

Tony

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post #4 of 19 Old 11-13-2007, 07:44 AM
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Why not kill the center channel entirely and go phantom center?

Might not sound as great as having a center speaker but if the center speaker is being irritating it should be a great fix.
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post #5 of 19 Old 11-13-2007, 11:20 AM - Thread Starter
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But will the volume control (link) I mentioned work?

I know that some centers have a control and IF it is possible to add one to my setup I would think that would be the best solution in the interim. I was hoping I could add one (inline) to the + side of the center speaker.

And thanks for the insight, I really appreciate it. The MMGs sound really quite excellent on the Panny but you can tell they do crave more power.

peace . . .

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post #6 of 19 Old 11-13-2007, 01:08 PM
 
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Buy an L-pad volume control from www.partsexpress.com. This should do the trick!
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post #7 of 19 Old 11-13-2007, 01:15 PM
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Is the system calibrated?

Craig

Lombardi said it:
"Perfection is not attainable, but if we chase perfection we can catch excellence."

My System
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post #8 of 19 Old 11-13-2007, 01:44 PM - Thread Starter
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Cool I really appreciate the help.

Would one of these be the right?

http://www.partsexpress.com/pe/showd...number=260-252

http://www.partsexpress.com/pe/showd...number=260-248

peace . . .

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Buy an L-pad volume control from www.partsexpress.com. This should do the trick!


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post #9 of 19 Old 11-13-2007, 01:54 PM - Thread Starter
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That's my goal but unless I am missing the point (my knowledge is limited) at the moment I cannot reduce the center volume enough to get past the ear test.

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Originally Posted by craig john View Post

Is the system calibrated?

Craig


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post #10 of 19 Old 11-13-2007, 09:35 PM
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Quote:
Originally Posted by tim99 View Post

That's my goal but unless I am missing the point (my knowledge is limited) at the moment I cannot reduce the center volume enough to get past the ear test.

What CC do you have? Unless it's 20 dB more sensitive than your Maggies, you should have plenty of "room" for calibrating. You need an SPL meter, ($50 from Radio Shack) and the test tones from your receiver or a disk like Avia. Start with all speakers at "Zero" and adjust them all according to the process described in your manual.

I doubt you need an attenuator to accomplish your goal. A volume control will be a serious PITA. Every time you change the volume of the system, you'll need to manually change the volume of the CC. That'll get old in a hurry.

Craig

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"Perfection is not attainable, but if we chase perfection we can catch excellence."

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post #11 of 19 Old 11-13-2007, 11:39 PM - Thread Starter
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Sorry I should have been more descriptive. My receiver allows for a +10/-10db adjustment as compared to the mains (which cannot be adjusted). If my center is at -10db the static test tone is still noticeably louder (by ear) than the main's are. If I had to guess I would say it needs to be turned down 3-4 more increments.

The center is a DCM KX Center Series 2 (specs below). Not only is it too loud it sounds really bad matched with the Maggies which doesn't make things any better. Maybe if It was quieter but I just don't think it was good fit. It was a gift from someone who didn't know that you should match speakers and there was a lot of love behind it so I have had to put up with it for awhile. By comparison it sounds kind of blaring and doesn't have the warmth the Maggies have. I've had it long enough now that I can swap it out for a Magnepan center without hurting anyones feelings but I have to get through holiday visits.

My hope was that I could put a volume control inline and just diminish enough that I could then use the receivers' center volume control to make the on the fly adjustments.

Thanks again for your help.

Peace . . .


DCM Center specs

Drivers: 2 - 6 inch DVM low/mid frequency with rubber surrounds; 1-¾ inch DCM horn loaded-neodymium tweeter
Sensitivity: 95 db
Usable power range: 5 to 100 watts
Nominal impedance: 8 ohms
Video shielding: drivers magnetically shielded
Frequency range: 50 - 20000 Hz
Enclosure type: Acoustic suspension
Crossover: PrestiDIgital electronic time equalization
Overload Protection
Dimensions: 22 ¾ wide x 7 ½ deep x 7 ½ tall

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post #12 of 19 Old 11-13-2007, 11:50 PM
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I would start by getting an SPL meter and trying to calibrate. You might find that it isn't as far off as you thought. And it would tell you by just how much (in dB) your center is playing too loud.

The first volume control you linked to is only rated to 15W, which would have me worried. However, most listening is pretty low-watt, so perhaps it would survive, despite being rated so much lower than your receiver is capable of delivering. I would worry that it would fail on the loud peaks, though.

This is a bit of a scientific wild-ass guess... but it seems like a simple resistor in series with the center channel to reduce it's volume by some fixed amount would work. And then use the center channel trim setting in the receiver to match it up, now that it's level has been knocked down by the resistor a bit. However, I am not sure what the specs on the resistor should be to handle the power or provide the right amount of volume reduction (seems like we should be shooting for ~5-10 dB or so, but use the results of your SPL meter test to know for sure).

Are the surrounds too loud, too? Or maybe they are less efficient than your very-efficient center (95dB is very efficient) and so are within the range that your receiver's trim settings can provide a match.

-Max
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post #13 of 19 Old 11-14-2007, 05:47 AM
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Quote:
Originally Posted by tim99 View Post

Sorry I should have been more descriptive. My receiver allows for a +10/-10db adjustment as compared to the mains (which cannot be adjusted). If my center is at -10db the static test tone is still noticeably louder (by ear) than the main’s are. If I had to guess I would say it needs to be turned down 3-4 more increments.

The center is a DCM KX Center Series 2 (specs below). Not only is it too loud it sounds really bad matched with the Maggies which doesn’t make things any better. Maybe if It was quieter but I just don’t think it was good fit. It was a gift from someone who didn’t know that you should match speakers and there was a lot of love behind it so I have had to put up with it for awhile. By comparison it sounds kind of blaring and doesn’t have the warmth the Maggies have. I’ve had it long enough now that I can swap it out for a Magnepan center without hurting anyones feelings but I have to get through holiday visits.

My hope was that I could put a volume control inline and just diminish enough that I could then use the receivers’ center volume control to make the on the fly adjustments.

Thanks again for your help.

Peace . . .


DCM Center specs

Drivers: 2 - 6 inch DVM low/mid frequency with rubber surrounds; 1-¾ inch DCM horn loaded-neodymium tweeter
Sensitivity: 95 db
Usable power range: 5 to 100 watts
Nominal impedance: 8 ohms
Video shielding: drivers magnetically shielded
Frequency range: 50 – 20000 Hz
Enclosure type: Acoustic suspension
Crossover: PrestiDIgital electronic time equalization
Overload Protection
Dimensions: 22 ¾” wide x 7 ½ deep x 7 ½ tall

I suggest you try "phantom" center until you can *safely* replace the CC with a CC that matches the Maggies better, (is there one?). Just set the CC to "Off" or "None". Your receiver will distribute the CC information to the L/R's. That will sound much better than a badly matched CC that can't be calibrated properly to the mains.

Craig

Lombardi said it:
"Perfection is not attainable, but if we chase perfection we can catch excellence."

My System
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post #14 of 19 Old 11-14-2007, 06:08 AM
 
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Since your receiver doesn't allow the adjustment you need to match levels properly the use of a high power L-pad on the center would work. Adjust the L-pad until the calibration levels are matched, and the receiver master volume control will then be able to adjust all speakers levels just as always. The L-pad is better than a fixed resistor as it allows the adjustment needed to calibrate levels without lenghty trial and error. Good luck!
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post #15 of 19 Old 11-14-2007, 12:53 PM - Thread Starter
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I need a 'real guy' amp first but yes there are some excellent centers made by magnepan.

The MMG's have excellent imaging so the phantom center works pretty well as long as everyone is sitting in the 'sweet spot'.

peace . . .

Quote:
Originally Posted by craig john View Post

I suggest you try "phantom" center until you can *safely* replace the CC with a CC that matches the Maggies better, (is there one?). Just set the CC to "Off" or "None". Your receiver will distribute the CC information to the L/R's. That will sound much better than a badly matched CC that can't be calibrated properly to the mains.

Craig


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post #16 of 19 Old 11-14-2007, 12:59 PM - Thread Starter
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I found this on the partsexpress site you mentioned.

Would this one be 'high powered' enough?

L-Pad 50W Mono 3/8" Shaft 8 Ohm
"L" pad lets you adjust the relative volume of individual drivers in a speaker system while maintaining a constant 8 ohm impedance. Works great with our L pad faceplates. Comes with mounting hardware and wiring diagram. Rated at 50 watts RMS.

peace . . .




Quote:
Originally Posted by floridapoolboy View Post

Since your receiver doesn't allow the adjustment you need to match levels properly the use of a high power L-pad on the center would work. Adjust the L-pad until the calibration levels are matched, and the receiver master volume control will then be able to adjust all speakers levels just as always. The L-pad is better than a fixed resistor as it allows the adjustment needed to calibrate levels without lenghty trial and error. Good luck!


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post #17 of 19 Old 11-14-2007, 03:24 PM
 
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Should work fine, it's cheap enough to experiment with. Good luck!
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post #18 of 19 Old 07-21-2019, 02:13 PM
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tim99 do you still have your DCM KX Center speaker? In case you do, let me add this:
I've created an Official DCM KX speakers and subwoofers discussion thread and I encourage everyone who owns, uses, is knowledgeable about, and/or has questions about DCM KX speakers and/or subwoofers to use and subscribe to that thread.
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post #19 of 19 Old 07-23-2019, 02:24 PM
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^^^

This thread is 12 years old, and Tim hasn't posted in 3.
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