Speaker Reconing Explained
Speaker reconing replaces a driver's moving parts (cone, surround, spider, voice coil, dust cap and leads) and keeps the basket and motor. With the maker's kit and a clean gap, the driver's parameters should return close to original. With the wrong kit or a rushed job, they won't.
What a recone kit contains
- Cone, usually pre-joined to the surround.
- Voice coil on its former, often already bonded to the cone.
- Spider, the corrugated suspension that centres the coil.
- Dust cap and tinsel leads.
- Sometimes a gasket, centring shims and adhesive.
The basket, magnet, top plate and pole piece stay. They are the heavy, expensive parts and rarely wear unless dropped, impacted or corroded.
The process
- Strip the old cone, surround, spider and coil with solvent and careful scraping.
- Clean the basket glue lands back to a sound surface.
- Clean the magnetic gap completely. Grit or steel filings left in the gap will score the new coil.
- Fit the new assembly with shims holding the coil centred while the adhesive cures.
- Bond the spider and surround, remove the shims, connect the leads, fit the dust cap.
- Test: DC resistance, polarity and a low-frequency sweep for rubbing.
Testing the result
DC resistance (Re) is lower than the nominal impedance: B&C's 8 Ω 18SW115, for example, measures 5.3 Ω. Compare against the maker's published Re for the model, not against "8". A reading well off, an open circuit or a scrape on a slow sweep means the job isn't right. If you can measure T/S parameters, Fs and Qts are the quickest check that the kit matches the original. See testing a driver with a multimeter.
Recone or replace
| Situation | Recone | Replace |
|---|---|---|
| Motor and basket undamaged, genuine kit available | Yes | Optional |
| Matching an existing stack of the same model | Good with the correct kit | Good if the model is still made |
| Basket cracked or bent, magnet shifted | Not suitable | Only option |
| Only a generic kit available | Parameters may change | Usually better |
| Kit plus labour near new-driver cost | Poor value | Better |
For an 18" sub, put the recone quote next to the price of a new driver. A new WM1850/8 is £275 for 1800 W AES on a 125 mm coil; a WM18X451 is £345 for 1800 W RMS on a 4.5" copper coil. Before swapping, check cut-out, bolt circle and depth against your cabinet (WM1850/8: 392 mm cut-out, 202 mm depth). See replacing a speaker driver and the replacement guide.
DIY or professional
A careful person can recone at home. The failure points are a dirty gap, an off-centre coil and poor glue lines. A professional shop has gap-cleaning tools, the right adhesives and centring experience, and will tell you if the motor is damaged before you spend on a kit. For high-power 18" subs, where heat and excursion are severe, the margin for error is small.
At home: work on a clean bench, keep steel tools and filings away from the magnet, follow the kit's adhesive cure times and don't power the driver until the glue has fully set.
Find the cause first
A recone fails again if the original cause is still there: no high-pass filter, a clipping amplifier or a limiter set too high. Run through is my speaker blown and why sub drivers fail before ordering parts.
Safety: recone solvents and adhesives can be flammable and give off fumes. Work in a ventilated space and follow the product safety data sheets.
Sources: B&C Speakers published data for the 18SW115 (Re 5.3 Ω, 8 Ω nominal), checked October 2026; Wavemark WM1850/8 spec sheet and WM18X451 product data.
Questions
What is a recone kit?
A pre-assembled set of a driver's moving parts: cone, surround, voice coil, spider, dust cap and lead wires. It fits the original basket and magnet.
Is it worth reconing a speaker?
For a quality driver with an undamaged basket and motor, when the maker's kit is available and kit plus labour costs clearly less than a new driver. Otherwise replacement is usually better value.
Does a reconed speaker sound the same?
With the correct factory kit and careful work, its parameters should return close to the original. A generic kit can change Fs, Qts and sensitivity.
What DC resistance should a reconed 8 ohm driver read?
Less than 8 ohms. Compare with the maker's published Re: B&C's 8 ohm 18SW115, for example, is 5.3 ohms. An open circuit or a reading far from the published figure means a fault.