The Warbler is based on the SDS 830656, a budget 5-1/4″ woofer by Peerless. At $16, the 830656 is the cheapest woofer I have. Peerless datasheet describes the 830656 as a subwoofer meant for a compact sealed box. From my simulations, that’s a bit far fetch. It doesn’t go down to 40Hz (-3dB) let alone in a compact sealed box. Perhaps with some electronic EQ but that’s pushing it.
I loaded the 830656 into a 13 liters vented box to have an idea of the sound. What I heard was simply amazing. Nice solid, punchy bass. For a mere $16, I have absolutely no complaints. Now, if only I can get it to work in a 2-way. This is not what the 830656 is meant for but it’s worth giving it a go.
Fig 1 – Peerless 830656 RAW nad Low Pass responses | Baffle Width=8-1/2″
The Black plot in Fig 1 is the RAW response of the 830656. The Blue plot is with a Low Pass. To keep the cost down, I avoided taming the cone breakup peak at 6kHz. I’m hoping that it will have minimal effects in the treble. Measurements below 500Hz are in Nearfield.
Fig 2 – Peerless 830656 Low Pass and Peerless BC25SC08-04 High Pass
The Red plot in Fig 2 is the Peerless BC25SC08-04 tweeter. This tweeter has a small horn which helps to shorten the acoustic centers of the two drivers. But more than that, I’m able to cross low and with a bit of effort, I can get a beautiful response. And best of all, it’s about $22.
Fig 3 – Passband Summed Response
The Black plot in Fig 3 is the summed response. Though no cancellations are observed in the passband, it is not as even as I would like. That’s due to the 6kHz peak in the 830656 roll-off. That’s the price I pay for not correcting the peak. It can be done. Just cost money, that’s all.
Fig 4 – Warbler Frequency Response
Fig 4 is the final frequency response of the Warbler. Frankly, this is quite an achievement. I am stretching the 830656 to the extreme. I am right at the edge before the cone starts to breakup. As for the tweeter, I’m also using it as low as it can go. Anything lower and the tweeter will start to scream.
Fig 5 – Null Response
To check on the crossover, I reversed the tweeter wires. The Null response in Fig 5 is quite encouraging. The phase alignment is almost perfect. For this project, this is good enough.
Fig 6 – Warbler Step Response
The Step response of the Warbler in Fig 6 shows a typical delay between the tweeter and the woofer. The woofer is behind the tweeter by about 200 microsec. This is quite acceptable. From this step, one can deduce that the tweeter and the woofer are both in absolute phase.
Fig 7 – Warbler Waterfall
Fig 8 – Warbler Toneburst Energy Storage
The Waterfall (Fig 7) and Toneburst (Fig 8) show minimal artifacts in the treble. No anomalies are recorded from 1kHz~20kHz.
Fig 9 – Warbler Spectrogram
The Spectrogram in Fig 9 shows most of the energy above 2kHz is dissipated by 2 msec. It is from 2kHz~1kHz that we see the effects of possibly cone ringing and baffle diffraction. Fortunately, most of the energy is dissipated by 6 msec. I doubt it will smear the music.
Auditioning the Warbler
This is heresy. A cheap woofer should not sound so good. I’ve never encountered a 5-1/4″ woofer that’s capable of producing bass of this quality. The bass is not only in abundance but it’s clear and punchy. What it lacks is the texture that very good (read that as expensive) woofers possess but we’re looking at only $16. I threw at it all sorts of music and the Warbler was a delight to listen to. Most visitors would be asking where the subwoofer is hidden when they hear the Warbler.
I see immense potential with this Peerless 830656. A budget 3-way is floating in my head. A 830656 for the bass, a Fountek FE85 for the mids and the Audax TW010E1 tweeter for the treble. Maybe even two units of 830656. That will increase the sensitivity to match the FE85. Definitely more projects to come.
Unless otherwise stated, all measurements were made with the mic at 36 ins, tweeter axis. Impulse Window=5ms. No smoothing applied.
May 9, 2020Projects