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Raven-DCR The Raven-DCR is my seventh time working on this Dayton RS180s. In this Dual Chamber Reflex (DCR), my aim is to extract as much bass as possible.
Fig 1 is the RAW response of the RS180s 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. What I’m interested in is the relative loudness between the bass and the midrange. The first thing that strikes most users is the series of sharp spikes from 7kHz upwards. This is scary for first timers designing their own crossovers. But fear not, they can be managed easily. Coming back to the bass and midrange, the rising midrange caused by the baffle step is clearly visible. I will have to attend to that if I want the bass to standout.
The Blue plot in Fig 2 is the RS180s carefully adjusted for the midrange response that I want. It is now at 80dB. This is 5db less than before. The spike at 7kHz has been brought down by -25dB.
Fig 3 is the RS180s with the Seas 27TBFC tweeter (Red plot). The two drivers are crossing at 1.6kHz. The 7kHz spike is 15dB below the tweeter. If it interferes with the treble, the only way is to EQ it out.
The Black plot in Fig 4 is the passband of the Raven-DCR. There’s a bit of gain in the summation, about 2dB-3dB. I’m not making any attempts to make it flat because this will add some presence to the midrange.
Fig 5 is the final frequency response of the Raven-DCR. The measurements from 500Hz upwards is within +/- 2.5dB. The bass sits at 85dB while the midrange is about 80dB. I’m glad to see that the spikes at 7kHz did not intrude into the treble. So no EQ is required.
Fig 6 is with the Null response when I flipped the tweeter wires around. A notch centering on 1.6kHz is seen. There’s good symmetry in the notch. This indicates the woofer and the tweeter share similar crossover slopes.
I’m quite surprised that the Raven is faster than other 6-1/2″ woofers. The transient is very clean, no breaks from take-off all the way to the apex. On top of that, it doesn’t slow down at 90% like others. It hits the apex at 300 microsec. That’s 100 microsec faster than the others.
The Waterfall plot in Fig 8 shows minimal artifacts in the Raven-DCR from 1kHz upwards. This is quite unexpected. Normally, there’s some hotness from 1kHz to 2kHz.
The Toneburst plot in Fig 9 shows very little excess energy. This is quite an exceptional performance from the Raven-DCR.
The Spectrogram in Fig 10 confirms the other plots. The only hot spot is a delayed energy at 3kHz. It is dissipated by 5 msec so it won’t present any issues. Sound of Raven-DCRI’m surprised at the Dayton RS-180s. I honestly did not expect it to measure this well. But it’s more than that, the Raven-DCR sounds great too. The midrange is outstanding. Voices can be clearly heard even with the louder bass. Vocals are not shouty. No shrieking in female voices. No sibilance. In the highs, the treble is free of harshness. The Seas 27TBFC is largely invisible in the music unlike some tweeters that blare out the highs. Some people are of the opinion that metal dome tweeters are bright, even harsh. Perhaps some are but not with this Seas 27TBFC. I have the fabric version too, the 27TDFC, and I love both of them. Sometimes, excellent tweeters fail to shine because the crossover is not right. This is very common. It took me many years to get the Seas to sound good. As for the bass, the loudness is the right touch. It doesn’t overwhelm the midrange, which to me is vitally important. The bass doesn’t have the control and texture of the Seas U18RNX but few woofers do. Even my Seas ER18RNX cannot match the U18 in the bass. The RS180s, however, does a decent job. The bass is distinct, not bloated. For a woofer of this price, I cannot expect more. For those that are thinking of building the Raven, I strongly recommend this Raven-DCR. This is the best by far. Unless otherwise stated, all measurements were made with the mic at 36 ins, tweeter axis. Impulse Window=5ms. No smoothing applied. |
January 10, 2021Projects
Fig 1 – Dayton RS180s RAW response in 40L DCR
Fig 2 – Dayton RS180s with Low Pass Filter (LPF)
Fig 3 – Dayton RS180s Low Pass with 27TBFC High Pass
Fig 4 – Raven-DCR Passband
Fig 5 – Raven-DCR Frequency Response
Fig 6 – Raven-DCR Null
Fig 7 – Raven-DCR Step Response
Fig 8 – Raven-DCR Waterfall
Fig 9 – Raven-DCR Toneburst Energy Storage
Fig 10 – Raven-DCR Spectrogram