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Crossover Gain
Dr. J
Posts: 209
G, Dra or Dennis -- When I raise the Crossover gains on Subs (BW18, 12db @50hz) It looks like the crossover point has some crazy overlap to the mids. What do you do in this situation? 1. Drop the gain down (lose power) 2. Put more separation between crossover points? 3. Buy a bigger amp for the subs so you don't have to adjust the gains?
I used the 260 GUI & entered in my settings and from the looks of the graph where the Subs cross to the mid -- just looks like it isn't a very smooth transition.
I used the 260 GUI & entered in my settings and from the looks of the graph where the Subs cross to the mid -- just looks like it isn't a very smooth transition.
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There are a couple of ways to handle this. You can reduce your gain and create a nice flat response. You can adjust your crossover frequencies to get rid of the overlap or you can put an EQ in the overlapping range. My first choice would be to flatten the response. Second would be to change the frequencies and third to use EQ.
I hope you are not referring to the \"drawings\" in the driverack. Please remember that the speakers have different efficiencies and that needs to be taken into account.
Just my opinion.
Mikey
Dennis
The ideal way (with a 260) to fix the problem, is once again, 1 stack outdoors and measure the response. Ideally, a balanced system with x-overs at unity (-0-) will give the least interference. This, by your admission, would require a bigger amp on subs or smaller amps on mains (or dial the amps back).
My example is extreme, but applies in principle, so the steeper the slopes the less interaction between bands, but gaining some delay issues.
Ain't this fun? As Mikey says, there are several ways to fix the problem, so go at it. Report back your solution.
DRA
2) You want the mixer meters to show clip (not yellow) and the DR at 15-17db (max).
3) An amp should (at least) be within 1 or 2 detents of being the same. How are you set up mono sub, stereo? How are you connecting to the amp?
4) Any altering of the signal (EQ, compression, etc) alters the output.
DRA
I was saying when the amps have equal output, the knobs should be within 1-2 detents of each other. In other words, if the detents are the same, then the outputs of one side should be within 1-2db. Anything more than that, the amp has problems. You didn't answer my question of how the amp is connected. Stereo out of the DR to the amp or mono out and using a patch jumper, or mono using internal amp connection? I'm trying to see if you might have a cable problem.
DRA
I pulled out the Driveware program and tried to recreate what you were looking at. You have to keep in mind that what you are seeing is a crude representation of what is really going on. What you can see is, by raising the gain on the subs, you are also raising the acoustic crossover point that Mikey spoke of and creating overlap. While you could lower the crossover point on the Sub band’s low-pass filter, you could also leave the crossover point as is and use a steeper slope such as L-R 48. I’m not saying this is the correct answer to your issue but it is worth checking out. The steeper the slope, the more separation you will get between bands and the more phase alignment issues you will run into at the crossover point so it is possible that what “looks� good sounds bad. Other than the sub band high-pass, Gadget usually recommends L-R 24 and the reason for that choice is, it offers the best compromise between separation and phase response. Since you are in heavy learning mode right now, experiment with all of the filters available in your DRPA so you will have a better idea of what tools are available to you. I will use a BUT 24 as often as a L-R 24 but my starting point is always a L-R 24.
Getting back to your current problem, the Behringer amp’s behavior don’t sound right. I don’t think it is a calibration issue. I think it’s broken. I am assuming you had no speakers or speaker cables hooked up while doing your tests and setting gain structure. I don’t find it unusual to have to boost the level of the subs a little bit on a small system in order to get even response. Keep in mind, it will change your crossover point and your time alignment at that point.
Dennis
My Gain structure was set with the speakers unplugged from the poweramp using pink noise otherwise wouldn't it be pretty loud?
Now getting back to my initial question or observation: IF I keep the gains all at 0dB (on DR) then the output level on the DR is slightly lower than the mid & high levels. If I RAISE the gain on the SUB crossover (9dB) I can get the output levels on the DR to be even for the subs, mids & highs. That's it! So -- what would be the better option? One or the other? Somwhere in the middle? Chuck the Sub amp and get a new one and try again? I don't doubt that the Sub amp may have a few issues BUT it does work and we get sound out of it.
Dennis
DRA
PS - You have probably done this already, but, hey.
Right now I am heading out to do a Flattening session. I will do one with the gains at ZERO and one with the gain set at 7dB since I can't just go out and do this anytime I want.
Set the low band to 20-out, mid band 20-out, hi band 20-out. How does that look?
DRA
50Hz to 100Hz is a fairly narrow band. A lot of speaker manufacturer's sub tunings will set the high-pass at 35Hz or lower and do a noticeable EQ bump around 40-50Hz. I don't think there is any real issue here.
The Behringer amp is another story.
Dennis