47Hz room mode woes...

[nvidia_7]

After tinkering around with REW I have found that I have pretty annoying 47.5Hz room mode. This is the FR from KEF LSX ii's and a KEF Kube 10b. Any recommendations? How is the rest of the FR as a whole looking?

 

[Weeb Labs]

I'm afraid that your vertical scale is far too large for me to make any meaningful observations. Could you please recapture the screenshot with a 50dB vertical scale and 20Hz to 20KHz horizontal scale?

 

[nvidia_7]

I'm afraid that your vertical scale is far too large for me to make any meaningful observations. Could you please recapture the screenshot with a 50dB vertical scale and 20Hz to 20KHz horizontal scale?

 

[nerdemoji]

now thats a very wonky in room response especially with the wavy HF

 

[Flexecutioner]

What microphone are you using?

 

[nvidia_7]

What microphone are you using?

UMIK-1

 

[kemmler3D]

Where did you put the mic, and did you measure one speaker at a time or stereo?

But, to answer your original question, that looks awful and you should definitely EQ those peaks out ASAP. The good news is I don't see deep nulls, so you can probably beat this into shape pretty easily.

Hard to say what's going on in the mid/treble until we know more.

It might help if you also posted another measurement without smoothing.

 

[GaryY]

I don't have so much experience, but I have 39Hz peak in my room due to the room length. In my case, this peak is very strong close to front or back wall and disappears near to the center of the room.

 

[nvidia_7]

Where did you put the mic, and did you measure one speaker at a time or stereo?

But, to answer your original question, that looks awful and you should definitely EQ those peaks out ASAP.

Hard to say what's going on in the mid/treble until we know more.

It might help if you also posted another measurement without smoothing.

This is just the right speaker, mic pointed forward at the listening position (centered and at ear height).

 

[kemmler3D]

This is just the right speaker, mic pointed forward at the listening position (centered and at ear height).

Got it. I'm assuming you used the proper correction file for that position.

There is nothing super shocking about the bass region, modes happen in every room.

It's hard to guess what happened above 1khz. It's not super common to see such wide dips in that range.

How big is your room and what sort of furniture / walls / wall coverings do you have in there?

 

[suttondesign]

EQ can readily tame the reinforcing modes.

 

[nvidia_7]

Got it. I'm assuming you used the proper correction file for that position.

There is nothing super shocking about the bass region, modes happen in every room.

It's hard to guess what happened above 1khz. It's not super common to see such wide dips in that range.

How big is your room and what sort of furniture / walls / wall coverings do you have in there?

This is a desk setup, so the LSX ii's are placed on a desk against the wall, with 12 feet to the back wall, and 10 feet of space to each side wall. Basically, the desk is placed in the center of a wall that is 25 feet long with the room dimensions being 25x12 feet.

 

[Daverz]

This is a desk setup, so the LSX ii's are placed on a desk against the wall, with 12 feet to the back wall, and 10 feet of space to each side wall. Basically, the desk is placed in the center of a wall that is 25 feet long with the room dimensions being 25x12 feet.

So the 2 kHz dip is probably "desk bounce".

 

[nvidia_7]

Hmm, now I am concerned. The speakers don't sound at all like the measurements suggest. I am new to REW but I believe I have it set right. I am using the umik-1 with the calibration file from their website for my specific serial number. The speakers are connected through USB, and I have all the settings set to the default settings, with volume set to 75db. I then click measure.

One thing I noticed is that the umik-1 shows 15dB less sound than my stand-alone dB meter. Maybe my mic is defective?

 

[rynberg]

It would be easier to look at if you apply psychoacoustic or 1/6-octave smoothing. Or at least average a few measurements by moving the microphone a few inches around your head position between each measurement.

The room modes are very simple to solve with a single listening position, basic PEQ can completely fix those peaks. Your overall frequency response on the other hand is really rough. Can you move the speakers even a foot away from the wall and raise them off the desk?

 

[nvidia_7]

So the 2 kHz dip is probably "desk bounce".

I just did a quick search on "desk bounce" and my frequency response above 2Khz looks very similar to other who place speakers right on top of a desk. I will have to do more measurements with them off a desk.

 

[sam_adams]

mic pointed forward at the listening position

That's the wrong orientation for evaluating the room's response. Get a boom stand for the mic. Place the mic in the vertical position—pointed toward the ceiling—at the same position where your head will be at the MLP. Load the 90º .cal file. Make your measurements.

 

[Daverz]

That's the wrong orientation for evaluating the room's response. Get a boom stand for the mic. Place the mic in the vertical position—pointed toward the ceiling—at the same position where your head will be at the MLP. Load the 90º .cal file. Make your measurements.

0 degrees pointed to the midpoint of the speakers is how I've always seen the instructions for measuring stereo speaker response (one speaker at a time, of course). I've only seen the 90 degree orientation in the context of multi-channel systems.

https://www.hometheatershack.com/threads/mic-orientation.133466/?post_id=1308978&nested_view=1#post-1308978

 

[kemmler3D]

Maybe my mic is defective?

Try doing a measurement super close to the speaker (nearfield) and see what the response looks like. If it's way off from what the LSX is known to do, that might be a clue.

 

[HarmonicTHD]

0 degrees pointed to the midpoint of the speakers is how I've always seen the instructions for measuring stereo speaker response (one speaker at a time, of course). I've only seen the 90 degree orientation in the context of multi-channel systems.

https://www.hometheatershack.com/threads/mic-orientation.133466/?post_id=1308978&nested_view=1#post-1308978

Nope. Eg Neumann MA1, dito Genelec GLM. MIC at 90deg. See also REW instruction. Yes both have their purpose but here I would also measure at 90 deg.

Still doesn’t explain the wavy HF response. My bet. Put the speakers on stands.