Monitor Audio R252 Replacement Woofers

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Hi

I'm looking to refurbish an ancient but beloved pair of Monitor Audio R252 speakers and am pretty sure I need to replace the woofers. One has a small whole in it and they both bass rattle badly when music is loud-ish.

I'm new to DIY audio, but am keen to get stuck in.

I'd prefer not to alter the cabinets if possible, so the screw holes on original woofers are the main dimension I need to adhere to. Diagonally, these are 8.5".

Can anyone recommend an appropriate woofer?

Many thanks,

Dominic
 
The Monitor Audio R252 was a Robin Marshall design from the 1980's.

AFAIK, it's an Elac 8" paper woofer used by KEF too. Quite nice IMO. Small voicecoil, rubber dustcap and lowish inductance I would guess. Must have good natural rolloff.

Frequently paired with a 88dB Vifa 19TD mylar tweeter or the 94mm SEAS 19TAF/G.

Crossover is simple bass coil and second order tweeter. Out of the box, I didn't like the similar R300-MD much, finding it a bit harsh. And I've redesigned the filter for more rolloff in the bass and fitted a different Monacor HT-22/8 cone tweeter. But the existing tweeter will probably work better with just an added 7W 22R resistor across it.

500404d1440474047-classic-monitor-designs-modified_ma-r300md_ht22-8.jpg


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You could try rotating the bass units 90 degrees to eliminate voiceoil rubbing, not 180 as usually suggested. Mark them with an up arrow on the magnet so you remember where you were. Small holes might be fixable with a bit of card and PVA glue. Check connections are tight too, even just taking them off and putting them back on can get you some fresh metal for good contact.

Replacing basses is trickier than you might initially think. It's a 184mm cutout AFAIK, about 215mm width max to fit the chipboard cover for width, and PCD for bolts of 218mm. Needs to rolloff naturally above 3kHz.

This SEAS CA22RNX one is doable, but the cloth cover is not going to fit IMO. It's simple enough to drill new holes for simple screws. Bolts are over the top really.
H1288-08 CA22RNX

I'd prefer to avoid out and out reflex drivers here, so Qts above 0.4 if possible.
 

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