DCX2496 and pair T48s cancelling out

[djengineer]

I run my pair of T48s on channel 2, and pair of DR250s on channel 1. I tried to run 1 T48 on each channel. The problem I'm having is when I do this, the T48s seem to cancel each other out. It's fine when I turn 1 up and not the other. I have the settings on both channels of the 2496 outputs going to my amp exactly the same (triple checked this) What is causing this?

[Doug Hart]

are your (2) T-48's together?

If so... sounds like one of them is out of phase.
To check, simply reverse the phase on one of the outputs of the DCX going to one of the Titans.
See if that fixes the problem.

[djengineer]

I've been running them in parallel both on channel 2 of amp, without issues. As I said, it's only when I try and run them on separate channels that I get this.

[Radian]

The DCX might be wired out of phase internally, who knows?

Try flipping the polarity in the software menu.

[Fish]

The DCX might be wired out of phase internally, who knows?

It's far more likely that the preset in use has polarity reversed on one of the outputs or one connector on either a cable or one of the T48s is wired incorrectly.

djengineer, check the preset first to confirm that all outputs have the same polarity. If that's all good, test all your cables (assuming you haven't already) for consistent pin-to-pin wiring and double-check ALL the connections in your T48s. Depending on how you connect your system, it's entirely possible that you could not have any negative effect from a single polarity flip.

[Gregory East]

Or the amp or cables are wired out of phase.

[djengineer]

I will re-check all that. However, if 1 of the T48s was wired wrong, I'm thinking I would have the same issue all along since I've been running them on the same amp channel. I have an extra 2496-to-amp cable I can try also. I'm trying to get more power to the T48s by putting 1 on each channel. I also did not notice the DR250s being out of phase or cancelling when they're on channel 1 all this time.

[Bruce Weldy]

I will re-check all that. However, if 1 of the T48s was wired wrong, I'm thinking I would have the same issue all along since I've been running them on the same amp channel. I have an extra 2496-to-amp cable I can try also. I'm trying to get more power to the T48s by putting 1 on each channel. I also did not notice the DR250s being out of phase or cancelling when they're on channel 1 all this time.

Why are you running two channels of the DCX for the subs? If you ran just one before, then it was in mono. If all you want is to gain more power by using two amplifier channels, then use the same output from the DCX as before to one channel of the amp, then either run the amp in bridge mode or use a jumper to parallel the two channels. There is no need to be using two ouputs of the DCX just to run two different amp channels.

[Bill Fitzmaurice]

The DCX might be wired out of phase internally, who knows?

Try flipping the polarity in the software menu.

+1. It's that or one of the cables to or from it is reverse wired.

[Sydney]

Why are you running two channels of the DCX for the subs?

Philosophy of Implementation?
One reason is because there are advocates who feel strongly that in a true stereo setup both channel have to have extended LF capability and be discreet.

( I try to stay neutral on it, I hear pluses and minuses in my experiences
Not trying to ignite the argument, but some would not consider mono subs)

Syd

[Bill Fitzmaurice]

Why are you running two channels of the DCX for the subs?

Philosophy of Implementation?
One reason is because there are advocates who feel strongly that in a true stereo setup both channel have to have extended LF capability and be discreet.

With some recordings from decades past that's the case. Modern recording studios listen to playback the same way the rest of us do, with 80Hz and below summed to mono, and the media is mixed accordingly.

[Bruce Weldy]

Why are you running two channels of the DCX for the subs?

Philosophy of Implementation?
One reason is because there are advocates who feel strongly that in a true stereo setup both channel have to have extended LF capability and be discreet.

The OP stated in the original post that he was running the subs in mono and only was going to two channels for more power.....thus, I don't think running stereo is the issue. I think there is some confusion on being able to run a mono signal to both sides of the amp (maybe he thinks he needs two signals to feed a stereo amp?)...at least that's what I'm reading between the lines from the OP's posts. Can't think of any other reason why you would need two signals to run subs mono.

[djengineer]

Bruce, I am running the inputs on my DCX as "summed" so there is no confusion about stereo. As you stated, I'm just seeing if I can get a little more power to the T48s. I am not seeking stereo bass. Moreover, as my original post stated, I have been running my DR250s off channel 1 so that shows how much I care about stereo sound anyway. I will dedicated my only amp to my T48s if a noticeable sound improvement is noticed from the extra power. So yes, I agree that how I have been running the T48s all along was mono. Not trying to change that at all.

Why am I (trying to) running 2 channels of the DCX to the subs? Because I paid good money for it, and does this very easily. It seems to be a waste of that if I make an XLR Y-cable to go from 1 DCX output to both amp channels, esp when I already have regular XLR cables. Also, none of this changes the fact that I have a fault in my setup that needs to be corrected. (From what I read), it seems undesirable to bridge an amp and then run parallel anyway...Correct me if I'm wrong on this! But if it yields more power to T48s then I'm all for it.

[Bill Fitzmaurice]

it seems undesirable to bridge an amp and then run parallel anyway...Correct me if I'm wrong on this! But if it yields more power to T48s then I'm all for it.

You can't bridge and run parallel at the same time. That could be the issue if you're trying to do so. Bridging seldom is of any value into less than 16 ohm loads.

[Bruce Weldy]

Bruce, I am running the inputs on my DCX as "summed" so there is no confusion about stereo. As you stated, I'm just seeing if I can get a little more power to the T48s. I am not seeking stereo bass. Moreover, as my original post stated, I have been running my DR250s off channel 1 so that shows how much I care about stereo sound anyway. I will dedicated my only amp to my T48s if a noticeable sound improvement is noticed from the extra power. So yes, I agree that how I have been running the T48s all along was mono. Not trying to change that at all.

Why am I (trying to) running 2 channels of the DCX to the subs? Because I paid good money for it, and does this very easily. It seems to be a waste of that if I make an XLR Y-cable to go from 1 DCX output to both amp channels, esp when I already have regular XLR cables. Also, none of this changes the fact that I have a fault in my setup that needs to be corrected. (From what I read), it seems undesirable to bridge an amp and then run parallel anyway...Correct me if I'm wrong on this! But if it yields more power to T48s then I'm all for it.

Ok, I see where you are going. While I understand the desire to use the gear - why complicate matters by having to duplicate settings on a second output from the DCX? A Y-cable is not necessary. XLR from the DCX to the amp. Depending on your amp connections:

1. Use an XLR or 1/4" short jumper from channel 1 to channel 2.
2. Run the amp in bridge mode. Then only one XLR cable from the DCX is necessary. An amp bridged at 4ohms will typically put out more power than the two channels at 8 ohms combined. Thus, the additional power you desire.

I run my Titans off a bridged amp - bought specifically because it was cheaper to buy a model that would give me the power I needed in bridge mode than one with enough juice running stereo.

How about telling us what speakers are in the Titans and what model of amp you are using.....much easier to make suggestions after looking up the specs....