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Grosbeak-XT The Grosbeak-XT is based on the 6-1/2″ Peerless 835025. I recently acquired this midwoofer when Parts-Express had a sale. I’ve never heard it before so this is a first. Based on the positive results from the Peerless 830874, I am hoping that this midwoofer will be even better.
Fig 1 is the RAW response of the 835025. Readers that have been following my posts would recognize the similarity with the Dayton RS180s that I used in the Raven-XT2.
The Blue plot in Fig 2 is the 835025 with a 2nd order Low Pass Filter. I adjusted the crossover such that the peak at 7kHz is -20dB less than in the RAW response. It would not cause any issues because my intended crossover frequency is about 2kHz.
Fig 3 shows the 835025 crossing over to the XT25TG30-04 tweeter at about 1.8kHz. I normally do not cross this low with a HiFi tweeter but I don’t have much of a choice with the 835025.
The Black plot in Fig 4 is the crossover passband of the Grosbeak-XT. They appear to be summing properly as no cancellations are observed in the crossover region.
The final Frequency Response of the Grosbeak-XT is in Fig 5. It looks encouraging. Nice and flat. I would not have been able to get this had I crossed the two drivers at 2.5kHz to 3kHz.
Fig 6 is the Null Response when the tweeter wires are flipped. It is not as deep as I would like it to be but it’ll have to do for the time being.
The Step Response (Fig 7) and the Waterfall plot (Fig 8) do not show any anomalies in the Grosbeak-XT. The Toneburst plot in Fig 9 shows some excess energy emitting from 1.5kHz but I doubt they are problematic.
The Spectrogram shows slight excess energy at 1.1kHz and 1.3khz. They vanished by 6 msec. There’s a hot spot at 2.1kHz but it disappeared by 6 msec too.
The Grosbeak-XT 3rd harmonics (Violet plot) is impressively low at -60dB below the fundamental. The 2nd harmonics (Red plot) and the THD (Blue plot) are at -50dB. Grosbeak-XT vs Cardinal-XT2I was sorely disappointed when I auditioned the Grosbeak-XT. The Peerless 835025 is nothing like the 830874. It sounds more like the Dayton RS180s-8. In fact, the Grosbeak-XT sounds very much like the Raven-XT2, perhaps with a bit more weight in the bass. It lacks the transparency and liveliness of the Cardinal-XT2. When you compare the two, it’s very obvious. It doesn’t mean the Grosbeak-XT is a bad speaker. It’s just that I’m very critical. I like my speakers to sound like the Scanspeak 15WU that I used in the Enlightenment. That’s actually not a fair comparison because the 5″ 15WU cost more than $300 a piece. But it does give me something to strive for, unrealistic as it may be. Unless otherwise stated, all measurements were made with the mic at 36 ins, tweeter axis. Impulse Window=5ms. No smoothing applied. |
December 2, 2020HIFI DRIVERS, Projects
Fig 1 – Peerless 835025 RAW Response • Baffle Width=8-1/2″
Fig 2 – Blue plot=835025 with Low Pass Filter
Fig 3 – Blue plot=Peerless 835025 with LPF • Peerless XT25TG30-04 with HPF
Fig 6 – Grosbeak-XT Null Response
Fig 7 – Grosbeak-XT Step Response
Fig 8 – Grosbeak-XT Waterfall
Fig 9 – Grosbeak-XT Toneburst Energy Storage
Fig 10 – Grosbeak-XT Spectrogram
Fig 11 – Grosbeak-XT Harmonic Distortion