Best high-efficiency speaker for Unison S6 EL34-based integrated

Hello audio junkies.

I've been running my 35w Unison Research S6 integrated amp with a classic pair of Proac Response 2.5, but have come to the conclusion the the Unison doesn't have enough juice to get the Proacs to sing. I've been doing some research on higher-efficiency speaker brands that may be a better match for the amp, like WLM, Tannoy, Zu, Living Voice, etc. Functionally, my room is 13" x 30" and I need to fire the speakers across the short dimension, positioned about 7' apart on either side of fireplace. Would like to find something that would charge the room with bass and image well.

Any recommendations for me? Can be modern or vintage.

-Bob R
You're talking some money with Living Voice and Tannoy and they're good choices.  If you want to save some money, IMO Coincident speakers are a great choice, especially used.  The Trenner and Frieidl speakers are also very good with smaller amps.  If you are in the NY area you are welcome to drop by to hear mine.  
Obviously, you have a couple of options. Before you get rid of your 2.5's, you should be sure its the right move. If you make a mistake, it will most likely be difficult to get another pair. I can tell you from first hand experiance that either an ARC VT-100, or a pair of Quicksilver V-4's, will breath new life into your system.

If you decide to go with new speakers, its a more difficult choice. Speakers like Zu and Tannoy don't have the same type of universal appeal of your ProAc's. Set them up right and the 2.5's can make just about anyone happy. Of the new speakers you list, Living Voice is probably the safest choice. I would also add DeVore. His customers are some of the most loyal in the industry. He makes both standard efficiency speakers, like your ProAc's, and has a high effifiency line as well.
There's a pair of high efficiency Heco Direkt listed now for 2300.00.  They received an outstanding review in the U.K. magazine Hi Fi Choice.  No personal experience however and no relation to the seller.
Sonist. Not sure if I've seen much negative about those anywhere.
Thanks all for the great suggestions... Has anyone had experience with Audio Note or WLM? I'd go for the Devore Orangutan O/93 or O/96, but they're too expensive, even second hand.
Check out Charney Audio.  I own his Concertos.  He has smaller models.  I have no affiliation other than being a satisfied customer and a personal friend.
Hi bob_rodgers.  May I ask what genre of music you typically listen to and at what volume?  I ask because you are looking to "charge the room with bass."  First of all I think charging a 13x30 room with good, clean, articulate, bass is often easier said than done.  And, if you are listening primarily to bass heavy music a more efficient speaker may not totally meet your goal -- some of the issue may be with your amp.  Don't get me wrong. I think your amp is a really sweet piece (I would love to own it); however, I have typically seen it associated with making magic in more modest size rooms with high quality monitors like the Opera Callas and Harbeth Compact 7ES-3 with classical, acoustic, and jazz music.  It also supposed to be really special with Quad 57's.  Obviously, none of these speakers would meet your needs. But even with larger and more efficient speakers, the 35 watts of EL34 may be softer and less controlled in the bass than say KT88 or 6550 based amps; especially in your large room.  Just a thought.  If you are married to the S6, then maybe something like the Zu Definition, which is meant for larger rooms and has a built in deep bass amplifier would give you what you seek in the bass department; but as SFALL states in an earlier post the Zu's don't have the universal appeal of your Proacs and you may not like their overall presentation.
forgot to mention....  In your large room, if you are open to open baffle speakers, Pure Audio Project Trio 15 may work for you.  There are some videos on youtube that have them paired with Unison Research Triode 25.
Wow - great advice! Thanks all. I'll check into every suggestion. Can anyone chime-in with any experience with Reference 3A and EL34-based amps?
The Heco I suggested is similar to the Devore 0/96, a German version if you will although the styling is more art deco.  At the 2300.00 used price it is way under what a used 0/96 sells for.
May we know the prospective budget?

We are Unision Research Dealers with an S6 its 35 watts are glorious as long as you move into a speaker that is 91 or 92 db efficient with an easy load your Proac 2.5 are 86db which is far from optimal for a 35 watt amplifier hence you are running out of juice.

Most of the Legacy line are 92db  and the Focus Signature SE | prodigious low end and work well in that sized room, they are also an incredible buy at $7,000.00 a pair for a hand made American speaker with state of the art Heil drivers.They are a sealed design so their bass is very tight and tuneful.

The room our S6 and Legacy's are in is 17 long by 14 wide with a 10 foot ceiling. 

Troy or Dave
Audio Doctor
877 428 2873

Dealer for Legacy, Unison Research, Kef, Tannoy, Graident, Paradigm, PSB, and many others.

Give us a call to discuss.

Hello all,

I will 2nd the Tekton Double Impacts,

They are capable of singing like a Angel with the Glorious 1watt 
Linear Tube Audio MZ2 preamp used as a Intergrated.

Take a look at the high efficiency (94+ db) single-driver Omega speakers (bookshelf and floor standers) ( .  I own a pair of the Super Alnico Monitors driven by a Unison Unico (original hybrid with two 12au7's in the preamp section).  My room is similar in size (15x25) to yours, but I have the speakers on the short wall.  This combination sounds wonderful, and I just had the amp modded and now sounds even better.  Really wonderful speakers.
Look at Charney Audio in Somerset NJ. He build high efficient horns designed on the tractrix theory. I have a pair of the maestro and love what I;m hearing. Fast, dynamic, coherent and ohh the bass! Imaging is off the charts excellent with emotional involvement.