Getting the DualCore’s bass correction going is a snap. You run the analog output of the DualCore unit into your preamp (or straight into your amplifier if you want to use the DualCore itself as a preamp). Connect the microphone, which is supplied with the DualCore, to the unit. Put the microphone where your head is when you listen (the mic has a long cord). Then you use the little hand-held remote to click through the self-explanatory menu. The unit will play a lot of bass sweeps—it takes several minutes to figure out what to do. When it is done it will show you a before and after measurement of the bass response. “After” will look a lot better! (Incidentally, as you get more advanced with the system, you will be offered the possibility of some spatial averaging—measuring at more than one position and combining the results. I am just speaking now of the basic operation.)
Then you are ready to listen. Plug any kind of input into the analog input and leave the analog output going into your amplifier—or you can put the unit input and output in the tape loop of a preamp as described above. That is probably the easiest way to get started fast, actually. The whole process is very quick and easy, no computers, no complex “learning curves.” Just follow the well-written instructions in the manual and there is almost nothing to it to get it set up.
Ah, but when you listen, there is something to it for sure. Gone are the bass booms of most systems. Precise bass with wonderful tonal and rhythmic accuracy are much in evidence. The bad effects of the room are all but perfectly eliminated.
If you took the quickest route through the menu, you are listening to correction up to 150Hz only. The next step to try is the effect of moving the top of the correction up to 500Hz and various frequencies in between 150 and 500Hz. A little experimenting here is good because exactly where you stop the correction will have some impact on how smoothly the transition to the uncorrected range occurs—and of course on exactly what kind of correction happened. It is easy to change, recalibrate, and re-listen.
There are also options available to change exactly how the correction is done. You can choose how much to have dips lifted (“Maximum” or “No Compensation” for dips are available options, with “Normal/Typical” in between); peaks are always pulled down. And if you wish, you can do corrections based on multiple measurements at different spots. There is a lot to experiment with, with further options discussed below, but it is all easy to follow using the owner’s manual and the displayed menus.
Two Examples and Some Things to Watch For
As you can see in Figure 1, the bass really does get largely flattened out by the DualCore.(unsmoothed data, as it comes from the DualCore). You can also see that the system does not attempt to fill in completely all the dips—and it is right that it does not try to do this. Often such dips are caused by cancellations of signals that are nearly in reverse polarity relative to each other, and filling them in is risky since the power increase at that frequency may have to be huge to bring the measured response up to flat. In the case of “infinite nulls,” frequencies with nearly total cancellation; the dip could not be filled in no matter what. Fortunately, deep narrow dips tend not to be seriously audible. And also if you move the speakers—and your listening position—around often enough you can get rid of them. I did not do that here because I wanted to illustrate the point about not trying to cancel them by EQ. In Figure 1, the dip at 60Hz is very deep, almost an “infinite null.”
As I said, moving the speaker can get rid of such dips in most cases and this is generally a good idea—to find a spot where deep cancellation nulls are not in evidence. Figure 1 had the speakers in positions that brought up the low bass but introduced irregularities in response from interaction with the nearby walls(Allison effect, as this is usually called).
In this case, moving the speaker to another position gave the smoother response shown in Figure 2. This is a measurement not smoothed beyond what the DualCore produces for you— just to show how well things can work if you work first at getting things in the right place.
And look at how nearly perfect the corrected response is! This is about as good a bass response, within the limitations of the speaker, as one is likely to get in listening terms. It is really smooth and the slight down-slope with rising frequency from the bottom of the speaker’s real bass extension is good in listening terms. Some people may prefer the Figure 1 position, however, for its greater extension, if reduced smoothness.
In this second position, the really low bass is still down in level as shown in Figure 2 again, but this is indeed the nature of the speaker—it rolls off starting around 50Hz anechoically. But in the speaker’s real operating range in the bass, the uncorrected response is now free of extreme dips. And after correction, the bass is essentially ideal. (This correction was done with the “Max” setting, which will be discussed momentarily.) One could pull up the bass below 45–50Hz with a “House Curve” setting, but this would run the risk of over-driving the speakers with material that had strong low-frequency content. One has to respect the limitations of the speaker itself always.
If the smooth rise as frequency decreases to 50Hz gives too much bass, you could run the correction with the “Typical” rather than the “Max” setting and get less bass. You can also turn off all compensation for dips and remove peaks only, which gives a situation with maximum headroom for “House Curve” modifications. This is all adjustable at your command!