As in, what do boundary speakers lack that speakers which need anywhere from 30 cm to 1 meter distance from the back wall possess that is causing a dearth of boundary speaker availability.
Or am I wrong? Are there far more speakers that suit boundary positioning than I am aware of?
I can’t get my head around the fact that the domestically most acceptable speaker positioning seems so poorly catered for.
.sjb
I guess there are three things that spring to mind.
I tend to agree with FZ about the parochialism of boundary designs. They tend to suit the British fondness for hovels of wattle and daub. But the world is a big place and manufacturers have tailored their speaker designs accordingly.
I’ve never really heard a non-boundary speaker beat my DBL’s.
By boundary speakers do you include ‘corner’ speakers?
If so then the Klipschorns are one of the best in my view
Sometimes practical reasons preclude boundary speakers. Baseboard heating and expansive windows come to mind.
My PMCs sit 9cm from the wall, which is exactly where my former SL2s were. And the ProAc Tablette 10 Signatures that I used between the SL2s and the PMCs are designed for boundary placement and sat in the same position again. My room is 3.6m wide, which seems pretty typical for modern family houses, so something a metre or so out from the wall just wouldn’t work. Bass ports on the rear seem to be the big issue here. Speakers like Kudos vent downwards and people seem to get away with even the big 808s close to the wall. So there are probably a lot more speakers that work well near the wall than are specifically designed to work against it.
Norman who ran UHES visited once. I think he did his PhD on speaker design and he was explaining to me how designing boundary speakers was actually a lot harder than free space designs. The answer is probably to design speakers that work both near and away from walls, and there do seem to be plenty around.
Norman Solomon. A very nice chap whom I recall a few lengthy phone chats with. Is he still with us do you know?
G
G
It really requires the designer to have near-wall performance to be a core performance attribute from day-1 of design.
I also suspect that the typically wide directivity of direct radiators may be more affected by near-wall placement than wave-guided or horn treble section. Just hosing down the wall with treble energy isn’t always the best answer. Bass section tuning requires similar fundamental considerations.
I don’t believe Norman is still with us sadly. I met him a couple of times at UHES and I bought my Proacs from him in 1999 when he worked in Audio Excellence in Worcester prior to that. Lovely chap, always chain smoking if I recall.
Well true boundary speakers need to built so the drivers are flush with the boundary or have extremely shallow cabinets… these tend to be offered more in professional installations… and there are many options out there, but yes consumer hifi speakers from what I can see don’t tend to focus on that. These boundary speakers are designed compensate for SBIR (bass) and boundary loading compensation (mids) … where effectively the boundary (wall / ceiling) becomes an extension of the speaker itself, which means heavy eq tailoring within the speaker based on environment to provide a respectable frequency response.
I am assuming for hifi purposes this starts to cause many variables of performance depending on construct / design and materials of the wall / ceiling.. which introduces unwelcome complexities of setup for the average consumer hifi enthusiast..so hifi market for such devices I suggest is very small.
Norman and Ian installed my nSub in my house. I remember Norman sitting on the sofa chatting and drinking tea while Ian crawled around on the floor connecting everything up. They were both really lovely. I don’t think Norman was in good health even then; it was back when they were operating from the castle.
Indeed. Many years ago I bid in an auction for a used XPS at UHES and came second. However the winner didn’t come forward and pay up at least for a while, so Norman offered it to me. I was about to pay when the winning bidder reappeared and wanted the PS. Since that would obviously disappoint me, Norman arranged for me to have their demo model for the price I had bid in the auction. Very honourable I thought at the time and still do.
Roger
Funnily enough, I think it was an XPS2 I bought from him (not that one!).
G
I think there are allot of inherent performance compromises with close boundary location. The biggest being the reduction of the illusion of stereo depth. Also bass tuning is difficult to get smooth…and this can effect the midrange. Pulling speakers away from boundaries does significantly improve performance…as does suitable room treatment….
I believe there are essentially two reasons why boundary designs are less common, the first is that so much depends on the interaction with a particular room, it’s easier to make a speaker that works best in free space, and such designs can often work reasonably well quite close to a boundary wall behind them. And of course that leads in to the question of sales or perhaps “saleability” - where the more flexible the speaker is to siting, the more sales it will potentially garner.
It’s also worth bearing in mind that boundary designs can are far less effective (and cause problems) with cavity walls and so modern house building doesn’t really work in their favour.
Would you say that the problem is with placing the speakers under discussion up against non load bearing internal walls Richard? I am lucky to have all single skin brick internal walls on the ground floor of my 1930’s house. My Nsats work great up close to one of those and my SL2 sound sublime within 10cm of a brick/brick external cavity wall in my room/ system
Anything that’s timber frame with plasterboard can be problematic. It’s a common build type in the US and trying to get speakers like SBLs and SL2s to work well with that was really difficult. Some resorted to doubling up the plaster board, but it was still far from ideal, to the point where in an effort to try to sell SL2s in the States, I recall the guys at NANA were at one point advocating using Allae PIPs, thus turning them into a reflex speaker, and then using them out into the room…
Interesting R. I wonder how some of our friends in Scandinavia mitigate that issue with the widespread timber frame as opposed to the UK modern brick and block builds.
I’m not sure that they sold that well there either. There were of course dealers who went above and beyond - in particular here I’m thinking of Stefan Mether who not only used DBLs personally but sold a number of pairs in Sweden.
As for UK modern builds, finding a solid wall is not so easy as you either tend to have low density blocks or dry lining being used and neither are great for boundary speakers. However, an old cottage with 3 foot thick walls made with clay, mud, manure or whatever came to hand, works really well!