DRIVE UNITS BY MANUFACTURER:
BC25SC55-04
This smooth sounding tweeter features a 4 ohm 25 mm voice coil, high energy Neodymium magnet assembly, a damped textile dome and ferrofluid in the magnetic gap for enhanced cooling of the voice coil. The BC25SC55-04 has a compact cropped faceplate (70mm diameter, 54mm across flats) with recessed mounting holes, and comes complete with a foam sealing gasket to reduce vibration. A finned heatsink aids cooling and results in high power handling for a driver of this size.
A full datasheet can be downloaded from the bottom of this page.
Resonant frequency (fs) | 1401 Hz | Nominal impedance (Zn) | 4 Ω |
Effective diaphragm diameter | 25 mm | DC resistance (Re) | 2.74 Ω |
Ferrofluid ? Y/N | Yes | RMS power handling | 100 W |
Recommended crossover | 2.5 kHz 12dB | Faceplate diameter (cropped) | 70mm |
Sensitivity (2.83V/1m) | 89.6 dB | Cutout hole diameter | - |
Peerless by Tymphany
Thanks for the review Miguel !
Will & Caroline
I have used these with both an active and passive crossover, crossed over at 2.8Khz and 3.2khz (dependent on the woofer).
This is a really smooth sounding unit but still has a lot of sparkle without sounding harsh. I did try it at around 2Khz, but is sounded harsh at higher volume.
Ideally you need to be at least and octave above the resonant frequency, so 2.8khz is a good crossover point for this unit.
Another plus point (from an aesthetics point of view) is that it looks like a more expensive unit than it is. The built quality is good. At just of £32 for a pair you cannot go wrong.
If anyone is interested I matched these up with the Peerless M16NH 6.5" Bass / Midrange in an front ported cabinet. Possibly the nicest sounding budget speaker I have heard for a long time!
Thankyou for your review !
Will & Caroline
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I always knew that Linn should never have stopped using Hiquphon tweeters. What I don't know is why it's taken me thirty years to fit a pair in my old Kabers. It's often hard to describe sonic character ....but to pinch Linn's old line from back in the day ...they're Simply Better.(even straight out the box with soldering iron still warm)
As my Kabers are passive,I had been a little concerned that the the 8 ohm nominal impedence of the OW1 would mess with the crossover slope. I needn't have worried....if its shifted the crossover point its much for the better.
Warm thanks also to Will and Caroline for a service in keeping with the outstanding quality of the Hiquphon product.
Alan
Been looking for a supplier of replacement drivers for some years.
Willy's HiFi had just the parts at a good price and they arrived in a couple of days.
Excellent service. Even a personal thank you hand written on the invoice.
A quick delivery and the tweeters are perfect on my mission 753 freedom speakers. Easy to fit . Highly recommend.
I’m no expert when it comes to speakers, but after some research (and a strong recommendation from ChatGPT), I went with the SB Acoustics SB65WBAC25-4 as a reference full-range speaker in this size range.
Having now tested them, I can confidently say they’re probably the best speakers I’ve ever owned. The clarity is outstanding—every detail comes through with incredible precision. The bass is surprisingly full and punchy for a speaker this size, and they handle power impressively well. For anyone looking for a high-performance compact full-range driver, these are hard to beat.