Hi,
I stumbled upon this site/thread while trying to decide what to do replace my IMF Professional Monitors with more "spouse friendly" standmount speakers + subs, or to revamp the IMFs. The money would be easier to justify for the former of course and there is the third option of doing nothing! Reading through this site has moved me towards the latter two choices, but I would appreciate any views! More about the options in a moment, but first a tiny bit of my IMF history in case it is of interested:
~1976 I bought a pair of TLS50 MkII from KJ Leisuresound just off Tottenham Court Road in London. Took em home to Hounslow by taxi amazing what fits in a London cab! I had be stunned at the difference between different speakers in the pretty expensive £250-£300 bracket (at least £2500 in relative terms today, or double that if related to house prices! The RSPMs were about £500 I think. None of the subtle differences that took a reviewer a whole weekend to hear the difference between a Linn LP12 and other turntable (Technics?) at a similar price three or four years later: speakers make a bigger difference than anything else!
Very happy with the TLS50s. Then in ~1991 I spotted a pair of Prof Monitors for sale for £350 and snapped them up! My brother in law, who had been following the then modernist line of thinking on speakers and had Naims (cant remember the model) gladly chucked them for my old TLS50s! He still has them, going strong.
And I still have the PMs. They are, I think, the Mk I (No plinth, and no Mk number) the owner had had a pair of low and very solid stands made, just enough to lift the castors off the floor to which I added spikes, and hed also apparently had some modifications done to the crossover. Maybe not as good as later versions, but still pretty satisfying! Best I ever heard, though, was once when I had a party in the garden nothing like free air loading and good volume to make them sing, and the bass was incredible which I can never achieve indoors (despite 22 x 14 living room).
Ive been using them all that time with a Musical Fidelity P170 power amp, which seems an OK combination.
But when a pre-amp fault blew one of the B139s recently (managed to find a replacement on e-bay), that started me thinking about the longer term if things go wrong, and also about whether modern drivers might be better, especially in the upper registers. And the thought of the cost of that made me wonder if there was any way of achieving as good a sound in a more spouse friendly package.
So
Possible replacement bass driver in the PM is the Volt 250.8 (suggested by Wilmslow Audio for this loading). Scanspeak R2904/710003 tweeters (chosen for their better dispersion than the ring version, ATC SM75-150 mid. WA say they can design a suitable XO. Any observations on this bass unit, or alternatives, for this enclosure? Any comments in general? Easy to assume that the best of modern drive units will be better, but the big question is, will they???
The other thought was standmounted 27 litre asymmetric reflex cabinets with downward firing ports, using same mid & hf as above, with Scanspeak 22w 8851T00 bass. These partnered with one (spouse preference) or two (if needed) BK Monolith subs. The biiiig question is, how would this setup compare with the IMFs. I expect the mid-high to be better on the basis of the drivers, but am very concerned about the bass, in the absence of TL loading, and using smaller cabinets supplemented with a sub (probably from about 60Hz). Anyone have experience of the Scanspeak bass units in this size reflex, and/or experience of the BKs? Re crossover: For ~£250 (parts only) Wilmslow Audio can supply suitable passive XOs matched to this specific speaker combination (so they say), noting that the ATC has particular demands. Alternatively for £100 more I could get a Behringer DCX2496 3-way active XO, and a pair of secondhand amps such as Samson Servo 170, and go for triamping with easy control over XO frequencies/slopes/EQ. I've no knowledge of these amps other than the specs, but that would mean cheap amps not on a par with my existing MF P170, vs passives that are less tweakable.
For reference my main use is music listening (from heavy/progressive rock, to classical, both chamber and dramatic orchestral, and opera, also playing a sampled piano.
All comments gratefully received!
Paul