Tang Band W5-1685 with Seas 27TBFC (Bi-amp)

Tang Band W5-1685 with Seas 27TBFC
Active Bi-amped

Having worked out the Tang Band W5-1685 system Q in a 10 liters bass reflex box,  I now move on to the next level, that is with a tweeter. For a start, I’ll use one of my favorites, the Seas 27TBFC. At this stage in the development, I use an active crossover to have an idea of how the speaker sounds like. If it’s satisfactory, I can then proceed to designing a passive crossover.

Fig 1 – W5-1685 with 27TBFC @ 2.5kHz 24dB/oct

The Blue plot in Fig 1 is the W5-1685. Measurements below 500Hz are in nearfield. The Red plot is the Seas 27TBFC. No passive components were used for this measurement.

Fig 2 – Summed Response Overlay

The Black plot in Fig 2 is the Summed Response of the W5-1685 with the 27TBFC. It appears there are no cancellations in the crossover passband, which is always a healthy sign.

Fig 3 – Frequency Response of W5-1685 with 27TBFC

Fig 3 gives a clearer picture of the final frequency response with the individual drivers removed. This is the response of the speaker that I will be listening to later. 

Fig 4 – Step Response of W5-1685 with 27TBFC

Fig 4 shows the delay between the two drivers. The tweeter takes off first. The transient of the tweeter is almost vertical, with the tip at less than 25us. The woofer, on the other hand, lacks the tweeter by almost 400us.

Fig 5 – Waterfall

Fig 6 – Toneburst Energy Storage

The Waterfall (Fig 5) and Toneburst (Fig 6) show some stored energy in the tweeter. 

Fig 7 – Spectrogram

The Spectrogram (Fig 7) provides a clearer picture when the frequencies are plotted against the time domain. The stored energy that were recorded in the treble region dissipated by 1ms. It is below 3kHz that the stored energy is more pronounced. However, most of them die off by 6ms.

Auditioning the W5-1685 with the 27TBFC

It’s been a quite a while since I last heard the Seas 27TBFC. It reminded me of why I like this tweeter so much. It is very smooth yet detailed. There’s not a hint of brightness. When the treble comes on, it doesn’t fight for attention. It just blends into the music.  How about the overall sound?

I like it. For a 10 liters compact box, there’s sufficient bass. The highish Q of 0.9 added quite a bit of meat to the bass. In exchange, I sacrificed some tightness in the bass. That’s a trade-off I have to accept.

Vocals are clear and not shouty. I think I can bring the midrange a up a notch when I work on the passive crossover. Right now, it’s just a preliminary test and I’m locked into a 24dB/oct crossover. 

The highs are smooth. The treble doesn’t spit at you nor is it sibilant. Diana Krall The Girl in the Other Room came out perfect. The treble in Lady by Kenny Rogers doesn’t grate me like some lesser tweeters. In that track, the bass is punchy and his voice cuts through the mix.

This speaker deserves a passive crossover. More to come.

Unless otherwise stated, all measurements were made with the mic at 36 ins, on axis. Impulse Window=5ms. No smoothing applied.