Before EQ and after EQ measurements - please advise if this is correct

blackhole · Sep 14, 2024

Hello REW experts,
In a small room using a vintage Sherwood s-7200 and PSB Alpha B bookshelf speakers in near field setup.
Using SMSL DAC via USB with PC as the source.
Using UMIK-1 and REW software please see attached curves before and after EQ.
Does the curve post EQ look correct? Please advise.
I used house curve based on Julian Krause video for filters.
Is there more information needed to asses these graphs?
I am using Equalizer APO.

Wayne A. Pflughaupt · Sep 14, 2024

Doesn’t appear to be enough difference between the before and after to make an audible difference. What do your ears tell you?

Regards,
Wayne

blackhole · Sep 15, 2024

i am changing the target DB level to 70.
So should i try different target levels until the sound is satisfactory?

linuxonly · Sep 15, 2024

blackhole said:
i am changing the target DB level to 70.
So should i try different target levels until the sound is satisfactory?

View attachment 73705

Hi,

If I understood correctly, you want to avoid any boost. You have 2 nulls at 87 and 105 Hz Therefore as a starting point, I would place the target below those nulls. Also adjust the crossover HP cutoff to match the natural slope of your RMS average. Here's an example. Lastly set the individual max boost to 0. If I made mistakes, please feel free to correct me. This would be my first 'diagnostic'.

Capture d’écran du 2024-09-15 09-20-12.png

moedra · Sep 16, 2024

It's probably much better to do an inversion, but that requires convolution. Are you are implementing the filters as data typed into an equalizer? Or are you using impulse responses in a convolver? I haven't used Equalizer APO in ages, but I know it can do both.

blackhole · Sep 16, 2024

linuxonly said:
Hi,

If I understood correctly, you want to avoid any boost. You have 2 nulls at 87 and 105 Hz Therefore as a starting point, I would place the target below those nulls. Also adjust the crossover HP cutoff to match the natural slope of your RMS average. Here's an example. Lastly set the individual max boost to 0. If I made mistakes, please feel free to correct me. This would be my first 'diagnostic'.

View attachment 73707

Thanks. I followed your steps.Please see attached before-EQ and after-EQ photos attached.

linuxonly · Sep 17, 2024

blackhole said:
Thanks. I followed your steps.Please see attached before-EQ and after-EQ photos attached.

Hi @blackhole

You have more linearity in the highs. I would have expected a more extended bass response (you lost a lot of frequencies below 55-60Hz) as well as a significant drop in SPL but at least you flattened the peaks in the bass region to some extent. Those dips in the bass region are caused by room and cannot be equalized: changing speaker location and room treatment is required (diffusion/absorption). You could post your mdat file and I would have a look to see if everything is related in context.

If youre using EQ, please do tell; however if you're able to use convolution (inversion), @moedra has made an excellent tutorial at https://nverxion.wixsite.com/meridiansoundworks/drc-rew and this whole thread would be of interest to you: https://www.avnirvana.com/threads/convolution-room-correction-and-room-curve.14005/page-2

You haven't specified. The after curve. Is it a result of afterwards measurements or calculated / predicted?

Best regards,

moedra · Sep 17, 2024

blackhole said:
Thanks. I followed your steps.Please see attached before-EQ and after-EQ photos attached.

If you do decide to follow my tutorial, my recommendation in the target design section is to place the target level somewhere between 69dB and 72dB, which is specific to your measurements. You will need to ignore the deep dip around 110Hz, which is a boundary interference null.

blackhole · Sep 17, 2024

I will try to follow your tutorial.

DanDan · Sep 18, 2024

Are you Measuring One Speaker or Both Together? https://www.irishacoustics.com/forum/measurement-and-control/acoustic-measurement-primer

JStewart · Sep 18, 2024

DanDan said:
Are you Measuring One Speaker or Both Together? https://www.irishacoustics.com/forum/measurement-and-control/acoustic-measurement-primer

Excellent work, Sir!

blackhole · Sep 28, 2024

I followed the steps in this link:

Digital Room Correction with REW | Meridian Soundworks

nverxion.wixsite.com

I don't hear any difference in sound quality with or without convolution filters.
I think it is better to listen without any room eq or convolution.

moedra · Sep 28, 2024

blackhole said:
I followed the steps in this link:

Digital Room Correction with REW | Meridian Soundworks

nverxion.wixsite.com

I don't hear any difference in sound quality with or without convolution filters.
I think it is better to listen without any room eq or convolution.

No difference at all? That's strange. What does your system configuration look like?

Wayne A. Pflughaupt · Sep 28, 2024

Some before and after graphs for us to evaluate would be helpful.

Regards,
Wayne

Before EQ and after EQ measurements - please advise if this is correct

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