Off-board balance solutions

OK so here's another bright idea to betray my lack of understanding of electronics and acoustics (at least), but here goes.

As I mentioned in another thread, I have to live with a rather sub-optimal arrangement of my main system, which consists of various sources into Roksan Caspian M2 and PMC GB1s. I have no choice but to set it up in the living room, where a combination of doorways, windows, frequently-used stove, and even-more-frequently-used TV dictate that the speakers are positioned, well, weirdly (and that I get to use them less than I'd like).



Don't trust the dimensions/proportions too much, but this shows the approximate layout. The lines of Xs are sofas. As you can see immediately, the one good thing about the room is that it's quite big (I guess about 20'x15') - not that that solves my problem, but it does allow for all my LPs, and having them in one place is my greatest victory so far!
Anyway the details don't really matter - we could talk about whether in my particular case I should do X or Y, but frankly there are no options that position the speakers such that they are well placed acoustically AND have a seat facing them! They sounded great on either side of the doorway on the left of the diagram (a speaker at position B2 and one at SPK A), but only whilst I moved the sofa out of the way. So we're back to having one at SPK A and one at SPK B. As you'd expect the result is not brilliant for the sound stage. There is a sweet spot where it is approximately balanced, but the depth of the stage and the clarity of the distribution of instruments is not like it was when the speakers were around the doorway. I want to fix this. I have read with great interest DaveG's thread (http://audio-forum.gspaudio.co.uk/room-treatment_topic2872_page1.html) and the links suggested there, and would be interested in trying some room treatment - people don't seem to discuss layouts that are asymmetric quite like mine but there are doubtless gains to be had. But I don't think that would be a complete solution anyway.

Well enough beating around the bush and special pleading; to the point: I want balance! Yes, I know that my soundstage is being distorted by bigger acoustic problems with my layout than simple balance (by which I mean adjusting the perceived relative volume of each channel). I want to sort them too. And I know balance controls are not ideal. But I also know from using my previous integrated amp in this set-up (a half-decent NAD with balance control) that a small tweak to the relative volume of each channel can work wonders, because when balance is not right it's not just that the soundstage shifts to one side or another and you can just move around the room until it's right. Instead the instruments get stacked up on one side, and moving your seat may well change where appear to be stacking up, but will not really fix the soundstage. Consider that part of the reason why, in my case, the balance sounds shifted to the left is that that corner of the room traps sound (and it was a whole lot worse when the speaker was near the rear wall by the TV). Reducing the output of that channel seems to help redress this sound trapping in a way that moving yourself to the right can't.

Of course like most higher end integrated amps, let alone pre-amps*, the Caspian has little more than input selection and a volume pot, and for all the right reasons that I was quite happy with when I bought it. But nevertheless my question is, does anyone know of off-board solutions to balance control? I've never seen one (aside from as part of the capabiities of a graphic EQ, which is definitely not on my wishlist!) Ignoring acoustic treatments and non-viable layouts for now, I can imagine several electronic solutions, some that exist and some that I've never seen (and here I will demonstrate again my ignorance of both the market and of the design of electronics):

• use proprius power amps, each with their own gain control ;-) Sadly beyond my budget today!
• use an in-line attenuator on one channel only of each source. I don't think there's a GSP one, sadly. This would offer a fixed degree of attentuation on one channel. It would be great if there were a range of attentuation available, or if they could be built so as to swop out components to adjust this.
• use an in-line attenuator on one channel only between pre- and power-amps, or use the tape loop like people used to do with an EQ (this has downsides but would mean it's easy to bypass too).
  
• a new gadget that has an actual balance control of some variety, positioned as above (before power amp or in tape loop)
• some sort of attentuation - fixed or adjustable - at one end of the speaker cable. I imagine something akin to a banana plug that perhaps increases the resistance on one channel only. Easy to install, you could daisy-chain them to increase the effect!
  

I don't know which of these would be the least noisy solution and most fitting from a hi-fi point of view. Nor which are even feasible! I'd love your thoughts on that, Graham.  Personally I like the last idea best, but haven't the faintest idea of whether it's possible to do this effectively. But it seems to me that we can make huge gains from small things that might be imperfect from a hifi POV but actually add much more than they lose, given the real-life compromises we sometimes have to make with set-ups.

What do you folks think? Should I be taking a long, hard look at myself in the mirror for even talking about redressing balance issues via electronic means? Are any of these solutions viable or extant? Any other thoughts?

Thanks!

Jeremy (now off for a weekend of wedding celebrations but doubtless checking this thread during photo sessions and speeches)


*before the NAD integrated I used a Cambridge pre/power combo with separate volume pots for left and right. That seems like balance done the right way. I still use it for its phono stage, actually, but not for much longer!

Perhaps digital room correction is an option. I know nothing about it but I'm sure I remember that someone here uses it to optimise their system... (Andrew perhaps?). Dunno how much of your listening is ripped files or streaming.. there might be a software solution that works

Edited by DaveG - 10 Jun 2016 at 1:25pm

DaveG wrote: Perhaps digital room correction is an option. I know nothing about it but I'm sure I remember that someone here uses it to optimise their system... (Andrew perhaps?). Dunno how much of your listening is ripped files or streaming.. there might be a software solution that works

Could you put the speakers at each end of the X's and the sofa out from the left hand wall? That would give some symmetry, including a triangular arrangement between speakers and the listening point.