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Bass null with two speakers but not on their own?

But 99% of the recordings are mono approximately from 60 Hz down except extreme cases of more or less old recordings.

This is incorrect. @Sokel and I have been investigating this in this thread.

To the OP: I am 99.9% certain that the dip you observe is due to phase cancellation. This means that phase correction is the correct approach, and not a boosting EQ.

Without examining the .MDAT, I can't say how many degrees out of phase your speakers are in that specific band. If it is exactly 180deg out-of-phase, the hole that needs to be filled is infinitely deep and no amount of boosting EQ will ever fill it. Fortunately most phase discrepancies are not 180deg, so phase cancellation dips can be partially filled. I would suggest leaving a boosting EQ as the last resort after phase correction.

If you like, you can upload the .MDAT (you need to zip it first) and I will have a look.
 
This is incorrect. @Sokel and I have been investigating this in this thread.

To the OP: I am 99.9% certain that the dip you observe is due to phase cancellation. This means that phase correction is the correct approach, and not a boosting EQ.

Without examining the .MDAT, I can't say how many degrees out of phase your speakers are in that specific band. If it is exactly 180deg out-of-phase, the hole that needs to be filled is infinitely deep and no amount of boosting EQ will ever fill it. Fortunately most phase discrepancies are not 180deg, so phase cancellation dips can be partially filled. I would suggest leaving a boosting EQ as the last resort after phase correction.

If you like, you can upload the .MDAT (you need to zip it first) and I will have a look.
Very interesting. I distinctly remember reading both Amir and Dr. Toole recommending looking at the summed response of the speakers up to 200hz or so. May I ask then - do you recommend equalising each speaker individually from, say, 20-500Hz, and then looking at the combined response afterwards to deal with problems such as OP‘s?
 
Without examining the .MDAT, I can't say how many degrees out of phase your speakers are in that specific band. If it is exactly 180deg out-of-phase, the hole that needs to be filled is infinitely deep and no amount of boosting EQ will ever fill it.

My hole around 48Hz is right at 180 degrees out of phase.

1737494722208.png
 
Very interesting. I distinctly remember reading both Amir and Dr. Toole recommending looking at the summed response of the speakers up to 200hz or so. May I ask then - do you recommend equalising each speaker individually from, say, 20-500Hz, and then looking at the combined response afterwards to deal with problems such as OP‘s?

It depends on what DSP software the OP is planning to use. Some of them take that decision out of your hands and will do it for you automatically. But if I were to do it manually, that would be the approach I would take: deal with the speakers individually, then measure them together and see if any problems emerge. You don't even need to measure them together, you can get a reasonable approximation of what will happen by adding L and R together. That saves you a bit of time.

Until very recently my thinking aligned with what Dr. Toole said in his book. It takes a lot to make me change my mind (particularly when we are talking about going against what Toole said!!) and right now I am in the process of thinking about it.
 
It depends on what DSP software the OP is planning to use. Some of them take that decision out of your hands and will do it for you automatically. But if I were to do it manually, that would be the approach I would take: deal with the speakers individually, then measure them together and see if any problems emerge. You don't even need to measure them together, you can get a reasonable approximation of what will happen by adding L and R together. That saves you a bit of time.

Until very recently my thinking aligned with what Dr. Toole said in his book. It takes a lot to make me change my mind (particularly when we are talking about going against what Toole said!!) and right now I am in the process of thinking about it.
Thanks for the response @Keith_W - I was asking because it relates to the thread, but also for myself, as I respect your expertise.

I’ll give it a try your way next time I calibrate. It’s just very difficult to achieve a very similar looking curve with both speakers in that 20-200hz region when one of them is in the corner, while the other one is in the middle of the room along the same wall.
 
Thanks for the response @Keith_W - I was asking because it relates to the thread, but also for myself, as I respect your expertise.

I’ll give it a try your way next time I calibrate. It’s just very difficult to achieve a very similar looking curve with both speakers in that 20-200hz region when one of them is in the corner, while the other one is in the middle of the room along the same wall.
We are on the same boat:
Post in thread 'Wharfedale Linton Heritage with Audiophonics HPA-S250NC first REW meauserements' https://audiosciencereview.com/foru...nc-first-rew-meauserements.46058/post-2205157
 
We are on the same boat:
Post in thread 'Wharfedale Linton Heritage with Audiophonics HPA-S250NC first REW meauserements' https://audiosciencereview.com/foru...nc-first-rew-meauserements.46058/post-2205157
Ah, you’re right - I’ve just been reading your thread yesterday! It’s never-ending, isn’t it?

Personally, I’ve finally gotten my L+R curves looking decent, but can’t make the individual curves behave. In due time, I guess. There are some interesting solutions outlined in this thread. And we‘re already successful if we manage to make the dips narrower, at least
 
would an all pass filter have a chance to offset one of the channel's phase just enough to diminish the destructive interference between the two speakers?
 
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