Proac Response 2.5 ...the Clone has Mutated !! Raven Ribbons Added...

[Steve M]

There has been a lot of discussion on this site and at Madisound about how to improve the hi-end ability of the Proac 2.5 Clone ?? In particular, there is a need to improve the 'midrange dip' that exists with this speaker. People have tried x-o mods; varying the port length; cabinet damping; adding/removing the dacron wadding etc...all with mixed results.

Well I think I've found an easy solution, but like all good things in life - it's not a cheap alternative.

ALL YOU NEED TO DO IS ADD A RAVEN R-1 RIBBON TWEETER (@$800AUD per pair) to the Proac 2.5, the end result is superb!! With the Raven, the DIY speaker retains that reknowned Proac bass, musicality and coherence but takes a HUGE LEAP in detail retrieval, transient snap and achieves an overall more refined treble quality and tonality.

By way of introduction my name is Steve M., and I constructed a Proac 2.5 Clone about a year ago (in West Australian Jarrah hardwood, finished with 12 coats of clear lacquer and black piano gloss front baffle, with gold badges etc. - it all looks magnificent,BTW). I was very happy with the sonics too, the x-o used is the original 'Jacq' modified circuit, but with all caps bypassed with expensive AEON tinfoil types. The sound of the speaker is excellent with an all-round virtue of being very musical aligned to an extended bass and good detail retrieval. IMO, the 2.5 clone speaker (and the Original) definitely punches above it's weight (considering the parts used) and will go down in history as a Classic design.

However, comparing the sound of the Proac 2.5 (unfair really, I know?) to my Quad ESL's; and another hi end ultra-thin-membraned Electrostatic loudspeaker; and a 90kg Reference quality double D'Appolito cone speaker using a Raven R-1 ribbon tweeter/ two Accuton Ceramic mids/ two 8" Cabasse 21NDC bass drivers - the sound of the 2.5 was sadly lacking in being too laid back in the mid; lacking the attack and decay of the more expensive drivers; and generally lacking treble quality.

So, how to improve on the sound of the Proac 2.5??

Well, I simply disconnected the existing Scanspeak tweeter and installed a Raven R-1 ribbon tweeter using the third order cross-over suggested by Raven/Orca Design. My own mods to this x-o circuit include bypassing the big Axon/Solen caps with small value Aeon Tinfoil caps and adding a 3watt 10 ohm variable resistor(very clean sounding too) on the (+ve) line of the Raven tweeter. This variable pot is absolutely essential as it allows you to adjust the treble intensity of the speaker to your liking (I like it set at 3.8 ohm). The result is 'right up there' with hi-end loudspeakers and very good indeed!

A speaker of this quality thrives on good amplification...

The amplification that I use include the Pass Labs Aleph 3 (there is something inherently 'just right' about this little power amp, regardless of price) and the wonderful Supratek Triode 'Merlot' monoblocs (a 6C33-CB Lamm ML2 style valve amp) the and the unique Supratek 'Cabernet' preamplifier. All pure Class A; Single Ended Triode valves; Transformer Coupled; Zero Feedback; valve rectified power supplies; lithium battery biasing etc. etc. Suffice to say the sound of Supratek amps is superb, and I would describe it as grainless, textured, pristine and clean like the best of solid state while maintaining the valviness that we all like. Check it out at:

www.supratek.biz (for Triode Amplifiers)
www.eraudio.com.au (for DIY Electrostatic spkrs)

Trust me on this one guys, the addition of a Raven ribbon tweeter definitely takes the humble DIY Proac 2.5 clone speaker into Hi-End territory, so why not give it a try? You can also quite successfully use the Raven tweeter and x-o on any other speaker (with a similar x-o point) you have at your disposal with , just dial in the required level of treble with the variable resistor.

Perhaps we can now call this speaker Steve's "Ribbon Response 2.5" ...

Regards,

Steve M.

[Matt]

Hi Steve

I have made the 2.5 and am looking now to see if I can improve the already great sound. I know your post was some time ago but can you explain a couple of things. You say you bi-pass the capcitors with high quality ones. I have heared the before but not sure what you mean by this. Secondly the XO for the ribbon. Is it just a case of substituting the Clone HP section with the XO suggested by Raven?

I have been looking for another speaker to make (Proac 3.8?) but can't find any details but if a 'simple' mod to the already great sounding 2.5 can be made seems a easier path to me and cheeper than a whole now build despite the cost of the ribbons.