Monacor Sound-4BT Spinorama measurements (CTA-2034)

[Ageve]

Here are some measurements of Monacor Sound-4BT.

It's a powered bookshelf speaker manufactured by Vistron (Dong Guan) Audio Equipment.

A slightly modified version is sold in Sweden, by "Intelligent Sound" (IS Monitor 4e). You've probably never heard of them, but it's a controversial manufacturer, claiming that the only thing that matters in a speaker is the crossover. Thus, they take inexpensive/bad speakers, replace the crossover with a secret one (hidden in epoxy glue) and sell them at 5x the price (or more).

Anyway, the speaker tested here is the original version. I measured the passive/right speaker, connected to the powered one.

My measurements are quasi-anechoic, with near-field port+woofer, combined and corrected for baffle edge diffraction, merged with gated outdoor measurements at 1m distance (5ms window).

A massive port/cabinet resonance and uneven woofer response. The tweeter peak at 9 kHz can also be seen in the 1m measurements (resonance or breakup).

Horizontal directivity:

0-90 deg for comparison with Stereophile measurements:

Vertical directivity:

Distortion:

I don't know why, but distortion at ~500 Hz - 4 kHz is lower at 90 dB SPL, while bass distortion is much higher (as expected). I measured three times (and the results above are with another power amplifier), but it made no difference. The mic was not clipping.

Here's a zoomed out view. 200% distortion at 50Hz.

I have attached a recording of the bass distortion. It's a combination of port noise and woofer distortion. The volume was low, and the woofer wasn't bottoming out.

It wasn't bottoming out during the distortion measurement either, but the port made a lot of noise.

The speaker isn't broken, and it hasn't been abused. It was just as bad when it was new.

My thoughts:

 

[pierre]

Thanks @Ageve for another speaker measurement!

With a small EQ, the speaker may get better esp. at low level: the score increased from 3.7 to 5.7. Note that this is an anechoic measurement and that you will still need to tame the bass in your room.

         SPK auEQ
-----------------
NBD  ON 0.49 0.38
NBD  LW 0.47 0.33
NBD PIR 0.47 0.34
SM  PIR 0.50 0.89
SM   SP 0.73 0.92
LFX       56   44
LFQ     0.94 0.94
-----------------
Score    3.7  5.7
w/sub    6.2  7.8
 -----------------

Histograms show progress on all curves: