Midrange compensation is an intentional dip in the 2 kHz region where the vast majority of tweeter-to-midrange crossovers are. In that region the tweeter is at the low end of its range and the midrange at the high end of its range and the directivity of the speaker goes through major changes. We found that if that region is equalized to flat, the change in direct to reflected ratio that happens because of the directivity variations causes voices to sound harsh (among other things). So, we have this implemented in the Audyssey target curve. With MultEQ Pro you can choose to turn it off, but we don't recommend it. This notion was observed 40 years ago by BBC speaker designers in their studio monitors. They designed their speakers with this "BBC dip" intentionally in the speaker response.
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Jonas Hansen If you are using horn loudspeakers which are crossed lower than 2khz (800hz in my case), does it make sense to have midrange compensation turned on?
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Audyssey Labs Hard to predict in advance. We have found it to be useful in most cased but have not done measurements on a speaker with such a low xover.
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Rickard L If I have a speaker with a crossover point at 3.8kHz and doesn't have a MultEQ Pro enabled unit, I would end up with both an undesireable dip around 2kHz and some undesireable directivity variations around 3.8kHz?
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Audyssey Labs Hi Rickard,
Our findings showed that the dip in the 2 kHz range is desirable regardless of the exact xover frequency of your speaker. With the Pro version of the software one can move the midrange dip to different frequencies, but this is not possible with the standard consumer version.
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Rickard L Any plans to make it a simple toggle in the consumer version? backported into the Onkyo x008-series would be nice...
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Audyssey Labs No plans at this time...
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Wolf Hi Chris,
with the Pro Version at Hand, do you recommend to move the midrange dip at the X-Over Frequency of the measured Speaker?
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Audyssey Labs Yes, that would be a good thing to try.
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pepar Hi Chris,
What about a speaker could "exempt" it from needing midcomp? Some report that they do not have "honkiness" with it off.
Thanks,
Jeff
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Audyssey Labs I have yet to hear one that doesn't need it... However, I have come across listeners who don't need it applied. The range of 2-4 kHz is where human hearing is the most sensitive. It is also the range where hearing loss starts to set in. If that is happening then an added midrange compensation dip will not be needed.
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pepar Nah, that can't be it. Audiophiles have perfect hearing until the day they die.
Jeff
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Thrang Hi Chris
So with my b&w diamond series, I believe the crossover is at the 4k point for the tweeters. I have pro, so I assume I would disable midrange compensation and create a custom curve with a 2db dip at 4k if I want to try the more custom fit approach noted above.
Is this correct, and specifically, how do I create the curve? I would assume its a three point setting, the center being at 4k. Where should I set the entry and exit points in the spectrum to isolate the dip within the proper range?
Thanks
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Audyssey Labs You would have to look at the before response to determine what shape the dip should have. Yes, the idea is to create a couple of points before and after the dip and then use 2-3 points inside to produce the right shape.
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pepar It is difficult to read any precision in those graphs. The Curve Editor's can be far more precise ... do you have any suggestions as to what the "inside" handles are doing?
And I guess that, since you are suggesting those points, one handle in the middle (between the two anchors) will not produce a good result?
Thanks,
Jeff
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Audyssey Labs The filter created by the points of the curve is smoothed to avoid sharp/jagged corners. Usually 2-3 points inside the anchor points are enough to provide the desired shape.
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Thrang Thanks Chris - my experiment was not too successful, and in fact, with my b&w diamonds in my room, even the default mrc is better off.
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Mathias Is there a way to disable this 2khz dip? My speakers dont need this attenuation due to the design being constant directivity from about 300hz upwards.
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Audyssey Labs Only with the Pro Kit. I'm not sure what constant directivity has to do with the need for the dip. We have found that the vast majority of speakers need it.
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Mathias My speaker doesnt need the 2khz dip, because there is no change in directivity at 2khz with this speaker, as it is constant. Well, even with the dip the response of MultEQ is way better than everything i have heard yet.
Thanks for the response.
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Cinemapro Chris, the description at the top specifically implies that changes in directivity is what may cause undesirable performance at the crossover region. It also mentions that using EQ to flatten response in this region causes the problems. This can be heard and seen in RTA (as irratic response) on many speakers. To Mathias' comment above, I have also seen some constant directivity speakers that measure very flat above 400Hz (averaged across the listening area) without EQ. The older JBL Synthesis S2C (without EQ other than it's passive crossover at 2.8KHz) comes to mind. Would a speaker that seems to have very smooth response through the crossover region be a candidate for not using the midrange correction? The S2C is a THX Ultra speaker with its more controlled dispersion. It also has a useful top end of 17KHz. Might those two factors result in a higher ratio of direct to indirect that would make the midrange compensation unnecessary or even undesirable?
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Audyssey Labs Technically, that's true. But based on my experience I have yet to hear a speaker that didn't benefit from the dip.
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Cinemapro Well, that definately puts the decsion is such a scenario in the realm of subjective interpretation of performance rather than anything technical. That said, I have lot of respect for your subjective opinion on such, but I'd sure like to have some more definitive description of the before and after sound to expect from the midrange correction. Isn't the perception of this also affected by the size and acoustic character of the room, and the throw distance of the LCRs? I would think that a big, lively room with low-directivity speakers benefit the most from the Target Curve 2 and Midrange Compensation. Vary those room and speaker parameters, and I suspect that the necessity/benefit and selection of these Audyssey Pro options becomes a more difficult decision. Of course, we would agree that is the task of an experienced Audyssey Installer.
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Audyssey Labs The most typical issue with the midrange is in the voice region. Voices sound overly pronounced and "honky" if the midrange compensation is not used. Yes, the default setting is a "best guess". An experienced installer can fine tune the midrange adjustment to suit the specific needs of the room.
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Cinemapro Thank you for that reminder about what to listen for in A/B comparisons.
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pepar A few seconds of Chaka was all it took for me to scramble to turn it back on and reload the filters.
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