EYEdROP0, you're glad I found you
Just kidding of course. I'm both an audiophile (to the degree of building some things such as preamps from scratch) and also a bang and olufsen lover, well mostly their pre-2000 era. There are two types of audio equipment that interest me. One type is the stuff that is completely home-made and often looks like it, but sounds incredible and costs practically nothing compared to the expensive high end stuff. The other type is the stuff that looks so beautiful you don't really care how it sounds. It becomes more of a functional piece of art. B&O does that for me. As for their sound quality, I'll agree with what some of the others have said.
There was a time decades ago when they really were producing high quality equipment even though the prices were high. They moved into a new era following the end of their beosystem 6500 and 7000 series, which was their last line of true separate component systems (amplifier, cd player, turntable, and cassette deck separate). Starting in the early 90's then they moved onto their all-in-one just press a button systems which began to sacrifice sound quality in order to be small and cute (the full 6500 and 7000 systems had weighed about 80 pounds). They also moved to active speakers. They started using relatively cheap drivers in the speakers, but because they were truly active, the digital crossover systems were able to compensate for the frequency responses of the drivers and yield a still moderately decent sounding speaker. In more recent years, they've fortunately moved back to high quality Tymphany (parent brand of SEAS and Peerless) drivers such as in their older speakers. The company is still in a terrible financial situation now though, and I don't know how much we'll still see of them in the next decade.
Now, about your penta 2's. I have a set of Penta 3's myself, which are practically identical. They aren't truly active even though they were the first speakers to take on the "beolab" name, denoting an active speaker. They're just passive speakers with amplifiers at the bottom. In fact, the speaker was also sold for a short time as a "beovox" (instead of "beolab") version without the amplifier bass. As you can see, you have 3 sets of drivers. It is technically a 3.5-way arrangement since the 4 midrange speakers have slightly shifted crossovers. The inner two are shifted slightly higher, while the outer two are shifted slightly lower in the frequency range. Unfortunately, in the case of the pentas, the drivers weren't matched all too perfectly, in either frequency range or quality. The tweeter you'll be happy to hear is a high quality SEAS 19mm ferrofluid unit. I don't remember the model number off the top of my head. The model is discontinued but you can still see the info in the discontinued section of the SEAS website. An equivalent SEAS tweeter is about $30 to $40. Now, the standard SEAS version was a 6-ohm nominal impedance driver. If you look at the back of your tweeter though, you'll see "BO" at the end of the SEAS model number, and underneath it will says "8 ohms". The tweeter is an 8-ohm version made for B&O. We'll get to why later.
Now you're midranges I'm sorry to report are junk. They're made by Haes, a German oem manufacturer for german car speakers, such as those found in your standard bmw. I actually found the same speakers on Parts Express a couple years ago for $5 each. They're very low quality. Furthermore, B&O has arranged the crossover to drive these speakers outside of their intended frequency range. This explains the fuzzy mid range you're hearing.
The crossover design isn't anything to celebrate about. I've forgotten most of what I learned about crossovers several years ago when I was trying to design one, but I still remember one of the major issues I saw with the penta design. The crossover was first used in the Penta 1 in the 80's, and only changed slightly all the way to the Penta 3 in the 90's. A good crossover impedance matches drivers. You can use a 6-ohm driver with an 8-ohm driver without an issue. Those numbers are fairly deceiving anyway though, as the impedance actually changes across the frequency range. The Penta crossover doesn't impedance match the drivers. Instead, they just tried to match the nominal impedances of the drivers themselves, which as I said aren't very meaningful numbers anyway. The main woofers are 8 ohms. So, they had SEAS modify their 6 ohm tweeter to be an 8 ohm tweeter. The midranges are 4 ohms each, so what did they do with those? They put each pair in series. The two center midranges are in series, and so are the two outer, yielding 8 ohms total they though. Unfortunately this reasoning works fine with resistors, but with speakers you don't just mix and match so that their nominal impedances add up to the same number and call it a day.
Now in the case of your rotting midranges, you can find new foam surrounds on ebay and replace the foam yourself. When you decide to undertake the refoaming let me know and I'll walk you through it. Oh, and if you can find them from someone else other than goodhifi I'd recommend trying those. He's a very friendly seller, but the dimensions on his surrounds are a tiny bit off. Not enough to be a problem, but it can be a tad annoying.
Mine are fine, but when they do go I'm going to replace them with higher quality 3" drivers such as these:
madisound.com/catalog/product_info.php?cPath=45_241_282&products_id=8305
As you can see, the outer plastic tabs will need to be trimmed so that they can fit in the circular recessed holes of the pentas. On the pentas the circular midranges drop into the face and are held by a bracket on the back. Obviously if you simply changed the midrange drivers they won't be properly matched to the crossovers, but they'll definitely do a better job of playing the frequency range their assigned by the crossover. I think the huge increase in quality of the driver alone would be noticeable. If I feel dedicated enough I'd consider pulling out the whole crossover and trying to match the new drivers to it.
Oh, and I've never been able to find any info on the woofers. So I have no idea whether they're great or junk. Also, I have pdfs of the penta instruction manuals and factory service manuals. If you're interested send me a PM with your email. Also feel free to ask any questions at all.
Good luck,
Austin
