Testing REW on Alesis M1 MK2 - Single Speaker Mono

[LevityProject]

As I figure out more and more about Speaker testing, I am curious about something more and more.

Is it possible to capture a general idea of the quality of a speaker with a single measurement of a mono speaker at close range (nearfield) using rudimentary tools. This is to answer the question for myself. Everything I am doing is super rudimentary. I'm not as interested in ultra precise measurements, but being able to get the overall tonality of a speaker.

For measurements
REW
MacBook Pro - just the built in mic.
Distance from Speaker - 1.5 ft.
Position of Microphone. first was pointed just above woofer, then at Tweeter height while pointed at the middle of the speaker.

Control Speaker
Adam T5V, reviewed Here (which I also own).

Hypothesis/ Question
Can a single measurement at nearfield range give enough information about the tonality of a speaker that it might be possible to bring old unmeasured speakers into the ballpark of neutral?

Why this came about
I was listening to my Adam T5Vs (Tuned) and then started listening to just one of them in Mono. as I turned up the volume, I realized I really liked what I was hearing. in Mono! I decided to throw on my Alesis M1 Actives (just one) and did some subjective level matched comparisons.

I immediately noticed that the Alesis M1s sounded woofy, mid bass heavy and lacked clarity. I took a quick measurement, and this is what I saw in the resulting graph from rew.

First Measurement just above woofer height showed really weird Tweeter behaviour with a massive and sharp dip around what I assume is the cross-over.

The Second measurement at tweeter height, pointed right at the middle of the speaker, was smoother and revealed wide issues in the midrange and confirmed the weird narrow spike at 133hz.

This I think is telling me I'd better only listen to these at tweeter height. Anything below that is going to be nasty.

I used REW's Auto EQ to EQ the speakers to a house curve that drops 0.5dB per octave from 200hz to 20khz (harman house curve) and re-measured with those EQ adjustments active.

This was the resulting final measurement.

interesting ...
I applied the EQ settings to the speaker using SoundSource.

Listening Tests
Single speaker, flipping back and forth betwwwen the Alesis and Adam, over many genres and many songs, level matched.

I don't hate what I'm hearing. Instruments are clear, bass is deep (but still wooly ... it may be the dual ports are flapping the bass), but overall it's a big improvement. There's still some issue in the midrange that I can't quite put a finger on.

I took a quick measurement of the Adam to compare apples to apples.

And this is where measuring speakers needs the right gear and approach. I tuned the Adams mathematically, but did not tune with the resonance of my room in mind. As you can see, there is a room mode at 133hz building up steam and the response seems more unneven than I thought it was. But I still like their tonality better, and I know that these measure well from the review. So this could also be the response bias of the Macbook microphone at play, for which no specs are released. Sooo ....

Using a proper measurement microphone is the next step in getting an accurate picture of the speaker in the room at a single point, but this was a revealing exercise and I think I can now repeat this whole process in under 5 minutes after learning the ins and outs

I think my original question / hypothesis may be half correct. It may be possible to take a single measurement at the right spot with a decent measuremnt mic to get a good enough picture of a speaker's tonality to be able to dial in correction that can roughly work. Will it be pinpoint accurate? No. Could you improve the sound of your speakers using this ultra basic approach? Probably! I came close with just a MacBook mic and REW... the important thing is that it helped me to start un-cooking the midrange on the M1s

 

[kemmler3D]

Cool post! I think this is firmly in "better than nothing / just ballpark" territory, but it's interesting.

I think it would be even more interesting to see what happens if you go about this with a proper measurement mic and following a proper pseudo-anechoic procedure. It does look like these Alesis speakers have some real deficiencies to correct, and with a clean measurement (including off-axis) I imagine you could make a much more dramatic improvement. The shootout between thoroughly corrected Alesis and Adam speakers might be more worthwhile at that point.

 

[staticV3]

The crossover dip goes away with sufficient distance, so a dip measured in nearfield is not necessarily an indication of any design flaw, and should not usually be "corrected" with EQ.

The 130Hz spike is most likely caused by the room or the unorthodox measurement rig.
Unless this was measured with a known good microphone at the MLP using the Moving Microphone Method, I'd again advise against correcting it.

 

[LevityProject]

The crossover dip goes away with sufficient distance, so a dip measured in nearfield is not necessarily an indication of any design flaw, and should not usually be "corrected" with EQ.

The 130Hz spike is most likely caused by the room or the unorthodox measurement rig.
Unless this was measured with a known good microphone at the MLP using the Moving Microphone Method, I'd again advise against correcting it.

Yeah that low-end spike is definitely not the speaker. REW automatically corrected it, and it did help - but it doesn't help with measuring for the purpose of finding a quick ballpark on the core tonality of a speaker.

I can hear the midrange loss if I position my head below the tweeter at the listening position. It comes back as I raise my head. lol.
with the Adam, the balance stays consistent as I move my head around to everything except extremes. Much better design, and now I know a little more about why I am hearing what I'm hearing, which is going to help me perceive smaller changes in tonality, which will help me musically, which is excellent