The Two Channel Advice Thread

Anyone have any intel on the new Harbeths P3ESR XD2? Was thinking about getting some p3esr's but now I may wait until these are released.

 

In the Harbeth User Group (official company forum), Alan Shaw said the changes in the XD2 series are a reformulation of the polymer used in the mid/bass driver cones and redesigned crossovers, resulting in flatter, smoother frequency response and better on/off axis behavior.

 

I have bias here, but how and why would this be required or even possible to result in meaningful improvements to what is already on the market? Why did they not introduce these developments in the previous "XD" version? Apart from something like graphene, what magical materials and formulations could they be using that did not previously exist? I don't think Harbeth is going to tell us how the sausage is made but I'm pretty skeptical that they are implementing anything that would be any better than what they have now. This feels more like the standard industry iterative "new product" required to generate buzz, FUD, and new sales.

 

Excuse me if you're a chemist (I'm a biochemist, among other things) and know all this already but I'm sure many don't.

Polymer plastics are made up of long carbon chains with a lot of hydrogen as well as other elements (like fluorine, oxygen, nitrogen, etc attached as "functional groups"). These chains are mainly bound together by weak forces, not ionic or covalent bonds. Think sticky spaghetti. Heat loosens those bonds before transition from solid to liquid, which is the drooping you see when you leave a low melt temp plastic doodad in the car in the summer.

My guess is he found/formulated a polymer plastic that had the characteristics he desired from his prior cone material but with a notably higher melt temperature. A higher melt temp should translate to stiffer plastic at room temperature which should make for a better cone material. He may also have altered any plasticizers he might use, or their amount.

Plasticizers are why you can have hard PVC pipes and soft PVC toys (they're used to soften the solid form of the polymer.) Plasticizers tend to "leak" out over time, turning the plastic brittle. Also, most of them are toxic - there was a big kerfluffle about soft PVC childrens' toys for this very reason about 15-20 years ago.

If he did indeed incorporate a better cone material, I'd wait for the XD2 version to release if I was in the market. If it doesn't sound better to you, you can probably still get the XD version at a discounted closeout price. Win-win.

*Note - I don't know shit about Harbeth speakers beyond reviews, and this is only my guess. At least it's educated, at The University of Texas in fact. Yes, The must be capitalized because reasons.

 

Could also be a matter of voicing as opposed to "we found a way to make it better." With the XD iterations, Harbeth lost some of their easygoing nature -- a little brighter and more modern hifi analytical. I was told by a dealer that was to keep up with market tastes -- B&W etc. Particularly with a new crossover, XD2 could be consciously further in that direction.

 

Skepticism is understandable and warranted in the audio industry. In the case of the Harbeth cone material, they had been using the same polymer formulation for over 12 years (including the XD series). The primary change in the XD series was the crossover. I have both the original P3ESR and the P3ESR-XD, and the sound did change noticeably – flatter, more neutral response and less rolled off in the highs.

 

I've been exploring nearfield desktop speaker options (I mentioned the P3ESR earlier), but it got me thinking—why not just use larger bookshelf speakers on a desktop setup? I'm considering things like the Philharmonic BMR, ATC SCM19, or even the Harbeth C7ES3.

Is there a specific reason people usually recommend sitting 5–7 feet away from a 2-channel setup? What’s the limitation when using bigger speakers in a nearfield situation, like 3 feet?

 

My thought is that you need to sit far enough that the center-to-center distance between the tweeter and woofer (assuming a 2-way) becomes negligible. Too close and you'll probably be able to hear that the sounds originate at different places. If this is the main reason then you should be able to get much closer to a bookshelf with coaxial drivers (e.g. kef ls50 type of speaker) or like a wide-band single driver (e.g. fostex). It might also matter how where the crossover is-- once the wavelength is below around 500 Hz, we're not quite as good at precisely locating the originating point.

 

Also... how big is the desk? some of these "bookshelf" speakers are over a foot deep. Add in the distance from the back wall etc and you don't have much desk left.

 

bunch of BMR owners are using them nearfield and they seem happy.

As to your question, my understanding is that speakers are designed such that the sounds blend at a certain distance, along the lines that @supertransformingdhruv mentioned. There's also the timing differences between the drivers that may be problematic; see the old Thiels for one designer's solution.

 

The BMR Monitors midrange is unusually wide field dispersion and smooth, thus “in character” with its superb ribbon tweeter.

To this Ribbon guy, it is VERY seductive, and I wouldn’t hesitate to use them to “replace” my Paradigm Ref. Studio 20’s I currently use near field in my office rig. But, TBH, were I to acquire them, or their bigger brother towers (MOAR bass), it’d be for my main rig, in my big room.

To me (others mileage may vary, and disclaimer: I’ve only listened to them for about 3 hours at a friends): they are not given their full potential if ONLY nearfield. They can do so much more

Thiel solved for time arrival with sloping (and very curved to minimize dispersion interference issues) baffles - the center of each point source/cone driver was equidistant from the listener,

Vandersteens solved it (a bit better - to my ears back then) by physically offsetting the drivers to align centroids, and then having minimal possible baffle…

That is a different effect that the directivity characteristics of the individual drivers, and that is where BMR are so clever wrt their 2” midrange… it is so similar flavor-wise that one doesn’t notice the differences from the tweeter so much.

 

I think I might just stick with the idea of an LS3/5A. I was considering the BMR since the wide dispersion seemed like it could work, but sitting that close would probably do them a disservice. My desk is about 24" deep and 56" wide, and I've got roughly a foot of space between the desk and the back wall to work with.

 

Yeah, the BMRs are back ported -- I don't think they would like that.

I would seriously consider the Phil True Mini for desktop use. Its voicing is very similar to the BMR, just not as much bass.

There's on interesting list of "best bookshelves" on what hifi that may also give you some ideas about options.

 

At close range, coaxials are nice and eliminate a bunch of those coherency issues. Something like the KEF LS50 is suuuuper easy to buy/sell/trade/recycle with hardly any loss and is worth a try.

I'm a fan of ATCs. All the bookshelf models are sealed so less worry about walls and placement. If you need the desk space, then maybe consider a smaller model like the 7 or 11. If you're looking at the 19, then consider bumping up to the 20 which will have higher spec drivers.