Ser at jeg har ikke lagt inn bilde av mine HL-5 i denne tråden. De har fått ny eier, men synes likevel at et bilde hører til her:
Har nå hjemme de små P3ES-2 som også spiller nydelig. Man blir glad i disse småtassene.
Kan nevne at det kommer ny utgave av disse av disse små monitorene. Her er Alan Shaw sin beskrivelse av de nye:
Well, first a little history as to why this speaker came about.
You know, the SEAS woofer (and tweeter) have been used in the P3, P3ES and P3ES2 since 1990 which means that the P3 has had nearly as long a production run as the venerable LS3/5a. What brought the LS3/5a to an end was that the supply of the (KEF) drive units dried-up*. For a third-party drive unit maker like SEAS to keep a rather specialist unit in production and hold the cost down and quality up for twenty years or more is an intolerable burden. And so, SEAS have been indicating to us by progressive price increases that they needed to cover their understandably increasing costs for what is a very specialist and custom-made unit.
The cost to us of that woofer unit is now really astonishing, and as the market has a clear price ceiling for a mini-monitor (like the P3ES2) simply because it is small, we have been squeezed in the middle with rising costs (drive units, cabinet, crossover, packing etc.) yet unable to pass those costs on. The P3ES2 may seem expensive but believe me for the engineering that's inside, it is a true bargain. So, we recently decided to buy in one final large stock of woofers from SEAS enough to cover ongoing production of the Monitor 20 (for the BBC), for several months P3ES2 production (we have a strong order book for it and many fans after nearly 20 years) and to cover spares requirements for years ahead. We have those - although our accounts dept. does draw my attention to the cost of this insurance stockpile.
So what was my brief for the new RADIAL based P3ESR then? Well, history repeats itself, but slowly. One of the reasons to introduce the P3 in 1990 was a political decision to protect Harbeth should KEF chose to discontinue the woofer/tweeter for the LS3/5a so that Harbeth could always offer a mini-monitor alternative. In fact, KEF's takeover by a well-funded and well organised overseas company extended the production of those parts for about ten years. So we are really at the same point now the the new P3ESR. The RADIAL 5" unit is Harbeth-made alongside the Harbeth-made 12" (for the M40.1) and 8" units (all models) and we have full control over our drive unit sourcing and have recently bought-in enough component parts to make these woofers for years ahead.
Concerning the excellent tweeter used in the P3ES2 - we've experimented with alternatives but returned to the SEAS custom-made unit because its really unbeatable - although, as you'd expect from a Scandinavian unit, expensive..
So, when designing the P3ESR woofer, what was the brief? The starting point was to re-measure the LS3/5a and the P3ES2 at the BBC anechoic chamber to refresh my memory about the overall response shape, loudness (sensitivity) and bass response. That done, I studied the curves, made a lot of cups of green tea (good for thinking!) and conceived a specification for the new P3ESR compared with the P3ES2 and LS3/5a ...
1. Match or exceed the overall midband sensitivity around 1kHz with similar power envelope for a small speaker
2. Design for an easier electrical load on the amplifier = increase the impedance from the P3's 4 ohms to about 6 ohms so that the P3ESR needs less power and a smaller amplifier
3. Reduce coloration in the presence region (and completely eliminate LS3/5a-type coloration at 5kHz by careful design of dustcap) so that the P3ESR sounds more like its bigger, RADIAL-based Harbeths. Remarkably so, actually.
4. Increase clarity, detail and stereo imaging and overall 'smoother' sound.
5. Maintain same bass response
All have been achieved although the manufacturing cost has increased a little. It must be said my respect for the P3ES2 is very high: it has a remarkable deep-bass output with a moderately powerful amplifier.
A more detailed summary of the end of the LS3/5a is here.
__________________
Alan A. Shaw
Designer, owner
Harbeth Audio UK