SuperMicro (Tang Band W3-1364SA + Peerless BC25SC08)

bc25_peerless-responsePeerless BC25SC08-04

The plot on the left is frequency response of the BC25 by Peerless.

Note the flatness from 2kHz to 10kHz. This is what you get when the tweeter is mounted on an IEC baffle of 1350mm x 1650mm (53″ x 65″). Now, none of us have speakers with baffles this humongous.

bc25_raw_on-axis_12db_cropThis is what you get in real life.

The Blue trace is the raw response of the BC25 with it mounted on my speaker with baffle dimensions of 130mm x 190mm (5″ x 7.5″). That is almost 1/10th of an IEC baffle.

And guess what? The result is it’s no longer flat. In fact, there is 3dB peak at 2,200Hz. This is the effect of baffle diffraction.

The Black trace is with a 12dB/oct filter.

w3_raw_on-axis_12db_cropTang Band W3-1364SA Crossover

Let’s turn our attention to the W3.

The Blue trace is the W3 RAW response.

The Black trace is with a 6dB/oct filter.

supermicro summed response

Super-Micro Response (No Smoothing, mic at 1 meter tweeter axis, 5 msec gating) Tweeter in Reversed Phase

Super-Micro Frequency Response

The above is the summed response with the BC25 wired in reversed phase. Disregard measurements below 500Hz.

Measurements made without any smoothing applied. The Super-Micro is exceptionally flat all the way up to 15kHz. Looks like it doesn’t deviate by more than +/- 2.5 dB.

distortion_05meter_twaxis

Super Micro Distortion ( 1/6 Smoothing, mic at 0.5 meter tweeter axis)

Super-Micro Distortion

Distortion is quite acceptable. Mostly 2nd harmonic (Orange Plot).

super-micro-3w-final-xover_blankCrossover Network

If you’re keen to build this design, contact me for the component values and the box dimensions.

Sound Quality

The Super-Micros exhibit an unusually focused sound. Very little smearing. Vocals and instruments are distinctly separated. And there’s depth in the music. The kind of effect when using a good compression driver/horn setup.

With their super flat frequency response, the Super-Micros are the ideal near field monitors for sound recording. For full range musical playback, just add an external subwoofer. Click on link to see Super-Micro 2.1 in use.

Update (Sep 30,2016)


Active Bi-amp Super-Micro

I decided to remove all the passive crossover parts and re-configure the Super-Micro for active bi-amping. This is easily done with my Synergy Kit. I designed the Synergy specifically for testing of 2-way speakers. Since the BC25 is the one giving the most trouble, I started with that.

bc25_2k5_3k5_4k5_hp

BC25SC08 Response (No Smoothing, mic at 1 meter on axis, 5 msec gating)

The 3 plots above are all with the Synergy’s built-in 18dB/oct crossover. Black is at 2,500Hz, Red at 3,500Hz and Blue at 4,500Hz.

full_2k5_hp_lp

Super-Micro crossed at 2,500Hz. Disregard measurements below 500Hz.

This is the response of the Super-Micro when crossed at 2,500Hz (18dB/oct for the W3 and the BC25).

There is a hump at the crossover point (2,500Hz). After that, a depression at 5,000Hz. That valley is not caused by the crossover. It’s the tweeter’s natural response.

full_3k5_hp_lp

Super-Micro crossed at 3,500Hz. Disregard measurements below 500Hz.

This is what the response looks like when crossed at 3,500Hz. Slightly better but still not good enough. The hump is less and the depression is still there.

full_4k5_hp_lp

Super-Micro crossed at 4,500Hz. Disregard measurements below 500Hz.

Now, this is what I call a proper crossover. Frequency at 4,500Hz. See how well the W3 and the BC25 sum.

full_4k5_xover

Best Response at 4,500Hz crossover frequency (Disregard measurements below 500Hz)

For clarity, the W3 and BC25 responses are removed. We can now see how incredibly flat the Super-Micro response is. Let’s not forget that no smoothing is applied to the plot. Even I am impressed. That’s why I said the Super-Micros will make fantastic near field recording monitors.

Just to be sure, I listened to the Super-Micros at 2,500Hz, 3,500Hz and 4,500Hz. They do, in fact, sound best at 4,500Hz. It’s a joy to listen to the Super-Micros with my Synergy amps. Nothing like a good active system.