REW Measurement – Neat Momentum SX3i + Vincent SV-237MK | 31Hz @ -3dB from 3m (No Subwoofer)

[claudia5]

I’m sharing real-world in-room REW measurements of the Neat Momentum SX3i standmount speakers, powered by the Vincent SV-237MK hybrid integrated amplifier.
Measurements were taken from the listening position at 3 meters, using a calibrated UMIK-1 microphone, no EQ, no room correction, untreated room.

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Setup:​

• Speakers: Neat Acoustics Momentum SX3i (Isobaric ported, passive)
• Amplifier: Vincent SV-237MK (tube preamp, MOSFET output)
• Mic: miniDSP UMIK-1 (calibrated)
• Software: REW v5.30
• Conditions: 3 meters distance, 75dB SPL target, stereo mode

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Measurement Results:​

• Clean and flat bass response down to 33Hz, with only ~3dB roll-off at 31Hz,
  measured at full listening distance – without any subwoofer.
• Both L and R channels show excellent symmetry.
• No major room cancellations or phase issues observed.
• Treble and midrange remain smooth and balanced.

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Conclusion:​

The SX3i delivers real full-range performance from a bookshelf design,
achieving true sub-40Hz extension in-room, passively, without DSP or correction.
This is one of the very few passive standmounts that can do that.


Attached below:
Full L+R REW graph (3m)
Bass zoom graph (10–200Hz)

 

[Keith_W]

Attached below:
Full L+R REW graph (3m)
Bass zoom graph (10–200Hz)

Welcome to ASR.

1. You did not attach the 10-200Hz graph
2. Your vertical scale is too zoomed out. You are showing -140dB to +180dB, that's a 320dB range. It is conventional to show a 50dB range. In your case I would suggest 50db - 100dB. Zooming out hides all the lumpiness and makes your graph look smoother than it actually is.
3. You did not apply any smoothing to your graph. I suggest 1/6 smoothing.
4. I can already see that the response is not flat down to 33Hz as you claim, even in the zoomed out graph. Regardless, unless it's an anechoic measurement, we don't know if the speaker actually goes flat down to 33Hz or not because of the room influence.
5. Suggest you read this thread and post an MDAT.

 

[DVDdoug]

If you like the sound, that's the important thing!


But... SPL (loudness) is another factor... It doesn't help if a speaker goes down to 30Hz but you can't turn the 30Hz signal up loud-enough to hear. Our hearing is "weak" at low frequencies.

I don't know anything about that speaker but it has a tiny woofer and it probably distorts with strong low frequencies. And you probably can't get "realistic" bass that you can feel in your body.

 

[claudia5]

i remade the messure

 

[staticV3]

Treble and midrange remain smooth and balanced.

Sans the 10dB deep dip in the upper mids

 

[claudia5]

Sans the 10dB deep dip in the upper mids

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You're absolutely right, and I appreciate the observation.
After experimenting with toe-in angle and adjusting the treble control on the Vincent SV-237MK, I managed to smooth out the upper mids — the dip around 2–3kHz is much less prominent now.


The biggest surprise, though, is how this compact bookshelf speaker (Neat SX3i) not only matches its manufacturer's specs, but also delivers truly impressive low-end performance in-room — hitting ~31Hz at -3dB from 3 meters, without any subwoofer or DSP.


That kind of bass extension is extremely rare in passive standmounts, especially in untreated rooms and without EQ