Starling-DCR (Seas ER18RNX with Seas 27TBFC)

40L Dual Chamber Reflex

2021 opens with my ninth attempt working on the Seas ER18RNX. As some of you may have realized by now, I have a Love/Hate relationship with this woofer. I love her midrange. My main grouse is her bass. I’ve never been able to get the bass to sound the way I want.

The Starling-DCR addresses this issue head-on. In all my previous Starlings, they are either in 13L or 15L boxes. This is the first time I’m loading the ER18 in a DCR of 40L. I’m hoping that with a larger box, it will give me the bass that I’m after.

Fig 1 – Seas ER18RNX RAW response in 40 L DCR

Fig 1 is the RAW response of the ER18RNX in the 40L DCR with a Baffle Width of 9″. Disregard the deep notch at 150Hz. That’s caused by a floor bounce in my setup.

I’m using this plot without a nearfield response spliced in at 500Hz. What I want to see is the loudness of the bass in relation to the midrange. It is obvious that the midrange must be tamed, otherwise the Starling-DCR will be too tiring to listen to. This is the major complaint with a lot of designs using the ER18RNX. 

Fig 2 – Seas ER18RNX with Low Pass Filter (LPF)

The Blue plot in Fig 2 is the ER18 with my new Low Pass network. The all important midrange is now at 85dB, the same level as the bass.

Fig 3 – Seas ER18RNX Low Pass with 27TBFC High Pass

Fig 3 is the ER18 with the Seas 27TBFC tweeter (Red plot). The two drivers are crossing at 1.5kHz. This may appear rather low for a dome tweeter but I can assure you that the Seas 27TBFC is more than capable.

Fig 4 – Starling-DCR Passband

The Black plot in Fig 4 is the passband of the Starling-DCR. I am pleased that no cancellations are observed in the passband which is an indication of good summing.

Fig 5 – Starling-DCR Frequency Response

Fig 5 is the final frequency response of the Starling-DCR. The measurements from 500Hz upwards is within +/- 2.5dB. The bass sits at 85dB while the midrange is slightly below. This is an exceptionally flat response.

Fig 6 – Starling-DCR Nearfiled

Fig 6 is with the Nearfield response spliced in at 500Hz. In a Nearfiled measurement, my microphone is about 1/4″ away from the cone. Because it is so close, room reflections is not be recorded. Notice the horrible notch at 150Hz is no longer there. What is also absent is the output from the bass reflex port. But that is not an issue because I can see the real output in the plots without the Nearfield spliced in.  

Fig 7 – Starling-DCR Null

To check on the phase alignment, I flipped the tweeter wires around. Fig 7 shows the Null response of the Starling-DCR. I am relieved to see the symmetry and the center of the null at 1.5kHz. I did not set out to get this. This is after everything is done.

Fig 8 – Starling-DCR Step Response

Fig 9 – Starling-DCR Waterfall

Fig 10 – Starling-DCR Toneburst Energy Storage

The 3 plots above, the Step, Waterffall and Toneburst do not register anything abnormal. The Waterfall plot shows minimal artifacts in the treble. The Toneburst in Fig 10 shows some excess energy at 3kHz.

Fig 11 – Starling-DCR Spectrogram

The Spectrogram in Fig 11 surprisingly shows no hotness at 1kHz. There is a delayed energy at 3kHz but it is nothing serious. It is dissipated by 5 msec. 

Sound of Starling-DCR

After 10 years and nine versions, I am proud to say I am now really satisfied with the Seas ER18RNX. I do not have to strain to hear the bass. It is loud enough. No subwoofer is required.

Due to the flatness in the response, the Starling-DCR is ideal for critical listening. She will produce recordings accurately. Some people may find this too revealing but that’s what the Starling-DCR is all about. If the recording is bad, it will sound bad. If it’s good, it will sound good. There’s no such thing as a bad recording sounding good with the Starling-DCR.

As for the quality of the bass, I am quite impressed by it. Most important is that the bass is clear. There’s no overhang. It doesn’t sound bloated, slow or constipated.

Overall, the Starling-DCR is a lively speaker with a very refined sound. I highly recommend the Starling-DCR for those that want to hear their music the way they were recorded.  

Crossover is available on request. Free for DIY. Not for Commercial use.
Unless otherwise stated, all measurements were made with the mic at 36 ins, tweeter axis. Impulse Window=5ms. No smoothing applied.