15" Monitor Golds with updated high quality crossovers (using SONIQS caps - link shown below) are due for arrival in the next week

http://www.soniqs.co.uk/ (See type SAX Polypropylene).

When they arrive, the plan is to compare the 15" Monitor Reds to 15" Golds in the Lockwood cabinets and finally decide which ones to keep.

The Golds have a treble emphasis/de-emphasis control fitted as part of the design (although it can be removed), so they will initially be assessed with this in-line with the signal path, set at 'flat'.

If it's immediately obvious that the Golds are better, even with this control present, then it will be removed and the drivers used 'wide open', and then also hard-wired directly to the crossovers, removing the present connector plug. It'll then be job done, and the Reds will be returned to the dealer.

The cable I'll be using for hard-wiring the drivers is CS-14 Hybrid from VDH (thereby maintaining a complete VDH cable loom from amp to speakers):

http://www.vandenhul.com/p_D03AF.aspx

The existing speaker binding posts on the Lockwood cabinets will removed and upgraded to these solder-less high quality gold over solid copper types from CMC:

http://www.hificollective.co.uk/images/cmc858lcul.gif

If the Monitor Reds end up being best, then they'll be receiving the same treatment, although these of course don't have the treble controls. The Golds in original condition will then be returned to the dealer. These will not be modified unless they are unquestionably superior.

Just to recap, the issues under test will be:

1) How my Copper amp with 6 Ohms taps reacts to both the Reds at 15 Ohms and the Golds at 8 Ohms - in short, ascertaining the effects of correct impedance matching between the amplifier and loudspeakers.

2) Taking into consideration the results of the above and the resulting varying sonic presentations, deciding which drive units overall give the best results, musically, in my system. A huge variety of music will be used in the test, and this will be done at some length. The last thing I want to end up with is a one-trick pony, which anyway I think will be unlikely.

Regardless of anything else, this will be quite an educational exercise. I'm not sure how many times vintage Tannoy drivers have been scrutinised and compared in this way. You can't accuse me of not being thorough!

Anyway, it should be fun... Full report will follow soon!

Marco.