Harbeth 30.1 or 40.1

@gt357s

mon 30 are midrange oriented monitor more for semi nearfield listening - will need bass reinforcement if run full range deliver dbs into 18x16 room

mon 40.1 are very full range, perhaps overly so... i had mon 40.1 before, they boomed, need to be far away from room boundaries - have you seen these speakers in the flesh?  they are huge boxes, know what u will be getting, if this is anything but a dedicated sound room there may be aesthetics issues

otoh, the c7 and shl5 bridge the gap between the two - c7 small box but more balanced high thru low, shl5 basically a larger version of c7 with supertweeter, similar voicing - 18x16 is good size but how will you set up the triangle, how close to room boundaries and therefore how much bass reinforcement?

Yes I have only heard 40.2 set up in large room away from walls. In smaller room closer to walls or corner with more bass reinforcement from the room I might be concerned going in about too much bass and no way to tame it other than eq or tone controls., which is always an option. They are big! “Full range” speakers in a smaller room is not always a good thing.
Something to be aware of. Too much bass can be detrimental to the overall sound, obscuring the otherwise lovely midrange and detail, and very hard to tame.

Vu of Deja Vu, who's a major Harbeth dealer, stated to me that the 40.2's needed 2' of clearance from side walls and 3' of clearance from front wall (behind them), all measured from the relevant edge of the cabinet.  The experience of the gentlemen in the link I posted earlier suggests that you can get away with less and still get very satisfying sound.

I have both the 30.1’s and 40.2’s in a room about 20’ x 20’ x 9’. Driving them with a Yggy DAC (one of the best), AR Ref 5SE preamp, and an A21 (to be replaced by a new AR Ref 150SE tomorrow).

They’re both superb, very much like a dynamic Quad ESL57 with bass - just like they sound on YouTube.

But... I think the 40.2’s are indeed almost too big for my room. They’re very loud and the bass is almost overwhelming - in a room that has no soft surfaces or upholstery to dampen the sound. But, the mids and highs are incredible, clear and detailed, without being strident, as well as rich and organic. And with a superb soundstage. Though, I do have a pair of Townshend Super-Tweeters, which adds tone, tenor and air. The bass is so strong, I’m thinking of using a DSP or Equalizer to tame it.

The 30.1’s have much the same sound, which fills the room, but a little less prominent bass.

I would note you really need an amp that can control the woofers - they require very careful system matching to perform to their potential.

I would likely use the same amps you see driving them so well on YouTube: the MA252 or MA352, or the Hegel H360, H390, or H590. Prolly the Hegel amps, which have superb damping factors, though the tube output of the McIntosh amps sound great with them too.

That’s one aspect I like about the set up I’m using, the AR Ref 5SE adds just enough tube sound to them to make them sound superb. I’m hoping the Ref 150SE maintains that sound, with a bit greater resolution, clarity and air, while improving the control over the woofers. The AR amps have a more neutral sound than many tube amps.

I’m not sure I would use other types of tube amps with them, other than possibly, something like the Atma-sphere M60, etc. - that have the current to properly control them, and to produce the resolution and clarity they can provide, if matched properly. Their sound is already very, very rich - almost too much so, without adding an overly rich tube sound.

But... I think... you would be pleased with the sound of the 30.1’s / 30.2’s driven by one of those amps. And... I’d get the Yggy, or one of the other R2R Dacs that sound similar or better (the Audio Mirror Trubadour or Dennifrips Terminator).  Though, the Hegel already has a superb DAC, though it may not have the R2R sound, it nevertheless sounds superb.  

So... one of the setups you see on YouTube that sound so incredible will probably please you the most. I’d prolly go with the Hegel and the 30.1’s / 30.2’s.  And what a bargain you have with the that set up!

Agree with @twoleftears , an 18' x 16' room is far from small and can accommodate at least 2-3 feet of clearance that most speakers need from surrounding walls to sound their best.  Based upon the listening preferences the OP described in his initial post, I'd be shocked if the 40.1's don't exceed his expectations.