Restoring Monitor Audio R300 bookshelf speakers.

Having established you can do all sorts of things with these 8" bass speakers, including adding Monacor HT22-8 cone tweeters with a simple enough circuit, I want to update adding the 94mm Morel CAT298 soft dome. If you can only find the 104mm version, a bit of woodwork is required.

Some of the red components are optional, but certainly add something. The main event is we have to take down the more efficient Morel CAT298 by changing the 2.2R input resistor for the SEAS 19TAF/G to 3.9R. However you do the circuit, simple or complicated. That's a couple of decibels, and just stops it shrieking or getting overly intrusive.

Replacement woofers aren't too hard either. People with an R352 reflex might think about a Visaton W200S-8 or a host of 8" SEAS or Vifa units. People with a closed box R252 might think about a bargain Seas P21RE/P.

I can't guarantee the cloth grille will fit, but hey, just measure! :)
 

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  • Monitor Audio Circuit CAT298.JPG
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  • Monitor Audio with CAT 298.JPG
    Monitor Audio with CAT 298.JPG
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  • Monitor Audio with CAT298 tweeter.JPG
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  • Monitor Audio CAT 298 Electrical.JPG
    Monitor Audio CAT 298 Electrical.JPG
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This project of mine is finally starting to happen. I’ve started to refurbish the boxes and will also redo the grills. I have ordered a pair of 19TFF and are planning to use the original bas drivers. After reading on the forum and looking at different crossover designs, I’m a bit confused and wonder if you cold confirm which of the designs will fit the original bas driver and the seas 19TFF? This would be very helpful!
 
Well done, Jonb87. Do your friends call you Sloop John B? :D

Did you say the SEAS 19TAF/G metal tweeters were missing? I patched mine up with new ferrofluid from Blue Aran. Some models came with a similar soft dome.

Here's the original factory Monitor Audio crossover:

714062d1541548033-restoring-monitor-audio-r300-bookshelf-speakers-monitor-audio-r300-md-original-schematic-png


If I was doing this now, I would use this one:

694035d1532786073-sb26adc-compared-sb29rdc-3rd-kef-style-png


I wouldn't worry about the exact bass coil value. 1.6mH to 1.8mH is nothing. You could probably reuse the 0.3mH too. Shouldn't make a huge difference, or you unwind it about 20% of the turns. I model with different but similar drivers quite often. Sheer laziness really. :eek:
 
Hi System7, cleaned the Pool and the young rebells with bleach

What would you please grossly advice for a 8" driver or 10" for a less than 40 l Vb at a very good price ?
8 ohms for something -F3 at 40 hz till 700/800 hz (87 db 2.83V there)...


Audax, Seas, Falcon, Visaton (often too high Fs though) ? SB ? I have in mind a littlier 3 Way classic (in mind 25 cm width bafle max or littlier for a better imaging... though bafle step is a b... !

cheers fron the continent
 
Hey System7, thank you so much.


(don't laugh the mid is the ScanSpeak 10f/8422 ... but I found the Classic SS bass of the same material a litle weak on the datasheet (I don't know so much really read anyway) and anyway don't want a too much big cabinet (40l is max).



Yes sealed has my preference as well, though box size & price is a concern so I lurked BR,

Ok, if this one makes both Sealed and cool price, it's perfect to my eyes, thanks again :) !