HiVi L6-4R with Peerless BC25TG15-04

The HiVi L6-4R is a reasonably priced 6″ cast frame woofer sporting a black woven kevlar cone. Selling at only $36.90 at Madisound, it would make a fantastic 2-way if it sounds right. Sounding right means it should extend high enough for me to cross to a tweeter at about 2.2kHz~2.7kHz. At the lower end, I don’t expect 40Hz. I’ll be quite satisfied with a F3 of 50Hz~60Hz. But what I would really like is to have enough mid-bass without having to resort to BSC. Is the L6-4R capable of these?

Having extracted the Thiele & Small Parameters previously, I decided to install the L6 onto a 13 liters box with the port tuned to 60Hz. I chose a budget tweeter, a Peerless BC25TG15-04 for this initial test. If the L6 meets my expectations, I can always upgrade the tweeter to find the best match. For convenience, I bi-amped the speaker with a 24dB/oct electronic crossover.


Fig 1 – HiVi L6-4R Response. Black=RAW, Blue=2.6kHz, Red=2.2kHz (24dB/oct)

Fig 1 shows the cone breakup is well under control, which translates directly to lower crossover parts. The Blue and Red plots are at 2.6kHz and 2.2kHz respectively.


Fig 2 – Peerless BC25TG15-04 Response. Black=RAW, Blue=2.2kHz, Red=2.6kHz(24dB/oct)

Fig 2 is the response of the BC25TG15 with the ferrofluid removed. The Blue plot is at 2.2kHz whereas the Red is at 2.6kHz.


Fig 3 – Summed response of L6-4R and BC25TG15 at 2.6kHz (24dB/oct)

Fig 3 shows the summed response of the L6-4R and the BC25TG15. For correct summing, the tweeter must be connected in Reversed Phase (Black plot). Connecting the tweeter back to In-Phase resulted in a notch centering at 2.6kHz (Violet plot). Note that there are no cancellations on either side of the crossover corner frequency. This is quite remarkable in that the woofer and tweeter are almost time aligned.


Fig 4 – Harmonic Distortion of HiVi L6-4R with BC25TG15 at 2.6kHz (24dB/oct)

Harmonic distortion is quite low. The 2nd and 3rd harmonics are about 50dB below the fundamental. On playback, both drivers sounded clean.

How’s the sound?

The L6-4R is everything I had hoped for. There’s enough bass on the low end and the mid-bass is audible without having to resort to a BSC network. The extended response and the well damped cone breakup helped tremendously with the crossover.

I see a lot of potential with this woofer. To do justice to the L6-4R, it needs to be paired with another tweeter. Whilst the Peerless BC25TG15-04 did the job, it is not as refined as a Seas 27TDFC. My next attempt is to replace the BC25TG15 with another tweeter around the same price as the L6-4R. More to come.