So, these SPEC RSP-501EX Real-Sound Processor things. The Japlish on the website offers little insight, but Tony explained it better in discussion as countering the back-EMF created by the driver voice-coils. I then compared it with the KEF crossovers of a couple of decades ago where they had tried to create a steady resistive load without any reactance. He agreed and apparently they took some research from the same chap, Mr Ishimi. So there is more than foo to the idea and with some degree of interest I tried them.



Connecting up is easy enough with a short run of cable to the 4mm sockets in my mid/treble speaker terminals (which are jumpered from the bass terminals with Coherent BD spade jumpers). The units are passive and require no power connection.

After playing a selection of my favourites, I can describe their effect as removing some midrange glare and darkening the image.  Nothing is missing and in fact detail stands proud due to the higher contrast.  Imagine an oil paining with a glossy surface and some light pollution shining on it.  Now spray it with a matt finish and look again.  The glare is reduced and it's much easier to see the detail and shades of colour, right?  It appears darker but more of the painting is evident.  This seems to be what's happening aurally.


I tried one of my favourite CDs Damien Rice - 'O' (featuring the lovely Lisa Hannigan).  The opening song delicate is a fantastic test of system resolution and dynamics.  At the start, the opening guitar is very quiet and the studio space and tiny tics can be clearly heard.  As the song progresses, the side drum has some serious welly and Damien's voice rises to a climax with background violins in a suddenly dense mix.  Get this track wrong and it sounds a muddled blur of a mess at the peaks when you set the volume to hear the intro clearly.  Reproduce it well and all the detail comes through, the dynamic swing from quiet to loud is breathtaking and things never fall apart when things get going and Damien lets rip.

So my early conclusion is that the SPECs do something to alter replay, and that something is to remove a layer of glare and allow further insight into the music while overall slightly darkening the presentation.  It's a subtle effect and it isn't going to rescue a poor system.  This is icing for an already well resolving and well setup system.  I have yet to ask the price so I guess I had better do so!

I note there is now an enhanced model called the RSP-901EX.

Nope, quite the contrary as with the side drum in the track described above. Of course, it's going to be very amplifier and speaker dependent. I shall keep listening and report back.

Wow, you're going for the full bifta!

You've certainly had your money's worth from the Chord. If the Belles stay with you as long, it's by no means a bad investment. Lovely looking amps too, which I know shouldn't count, but try telling my eyes that!

Well you've given the Belles a thorough work-out Martin, so you must be making the right decision - enjoy!

Do you still have both amps in the house?
Do they by chance have similar voltage gain?
If so, while they are both there, you owe it to yourself to see what happens if you bi-amp your speakers!!

The bi-amping experiment is something that I simply wouldn't be able to resist as I would want to see whether the result could seem greater than the sum of its parts.

Bi-amping the way I do makes my ML-11 a better amp when it isn't doing bass. This arrangement is much better than the ML-9 working full range even though that is a better amp. Of course two ML-9s would probably be even better but there's no spare cash for that at the mo' (one sold on Ebay last week for a piffling£700).

I did seriously contemplate acquiring another Chord. However, I subscribe to the Jacques Mahul (he of JM Lab) principle that one good amplifier or one good speaker cable is always better than two of lesser quality. For this reason, I stopped bi-amping and bi-wiring a long time ago.