Pio B20s . . . finally and again

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So, I finally got a pair after going back and forth with Zilla and others over their relative merits and issues for what seems like a year or more.

Actually, my mother got them for me. She insists on getting “toys” for everyone for Christmas, even all of us aging folk in the family (she did ask for a list, after all ;-p).

Quickly threw together a set of 16”x20” foam core baffles for them for my desk and did a quick EQ job on them through my Emu 0404. First off, I’m getting all the high end extension I need, sweet and airy, with minimal EQ. Sure, that’s no good for speaker meant for a setup that doesn’t allow this kind of flexibility (or for folk who think EQ is evil), but this is has the second best high end in my house (the best being a 2-way with B&G Neo3 PDRs for the top). Second, I’m able to get 5Hz-10Hz more extension on the bottom than I had been getting from my Kenwood KFC-6949s in the same size baffle in the same setup, with less EQ (though I have hit the barrier in this setup; even massively more bass boost only manages to clip the amp without any more noticeable extension (set “optimally” its down about 3dB at 50, though down maybe 12db at 45, 24 at 40, etc.).

Anyway, just on paper, they’re working for me better than the Kenwoods ever had, and, unfortunately, I felt that they had been working pretty well ;-p Subjective, critical listening shows that I really had been working with trash drivers all this time. Well, maybe not trash, but certainly not approaching hi-fi at all. The B20, just with the quick and dirty EQ to get the highs and lows back is smooth as silk. There nothing shouting at me to go back in and work some detailed curves to flatten everything out like I’d had with the Kens (big peaks at 2.2, 7 and 9KHz on those, plus a load of more minor niggles). I’m sure if I go in and work it, I’ll get some minor improvement somewhere, but my motivation to do so is negligible at best right now. They just sound great.

Now for the “and again” part. On the small OBs they sound great, but they’re missing the whole bottom octave and are less than authoritative into the next, so I’m contemplating building some sort of enclosure for them to help out. First choice would be a BiB, of course, but my floor space is at an absolute premium. There’s also the fact that I’d prefer to be able to build using 4’ lumber if I could, though I could be persuaded to go to 6’ stock if I can get significantly better results inside my footprint limits.

First I was wondering what might happen if I simply chopped the BiB down to a floor loaded 4’ high version, so a line length of 80-90” and a driver placement of a bit less than half (though that would be somewhat adjustible, I’d like to keep it up near ear height). Is there any set of BiB parameters that might get me to 40hz or less inside that limitation? How about in a 6’ version, line of around 120”, driver around 40” or so (though that can be shaved internally a touch without sacrificing much line and also allowing a slightly larger mouth without losing length)?

The second option I’m interested in but haven’t managed to find much to read about would be a 4’ version with an inverse taper, fat up at the driver end, down to a fold at the bottom and then skinny back up a the top where I would vent it simply, really just an inverted BiB in construction (though I would need 7 pieces instead of 6 ;-p). That would give a line of 92”-94”, a taper of anywhere from 2:1 to 4:1, I reckon, and a driver position of 4”-16”. Any idea if such a config would do anything desirable with this driver? It would certainly be easy and cheap to build (both of which are very important to me ;-p) and give me around an 8”x10” foot print which may be close to the largest I could manage without altering the layout of my office (which would be difficult to put it mildly, though if I could be convinced of the results . . .).

Final option would be just a tall skiny sealed or ported box. I don’t usually care for the ported sound, but what might be the effect of having the port exit centered behind the driver? I haven’t run the sims on these yet for the box sizes I might be looking at, but I’m guessing the sealed might start rolling at 60Hz since I won’t have much reinforcement and the driver will be so far off the floor.

Anyway, sorry for the lenghty post, and thanks in advance for any discussion you might offer for it.

Kensai

Comments
 
There’s a musician in my office that really likes the sound of the B20. He’s a sax player and loves jazz. He likes the top end of the Pioneer/Piezo more than anything I’ve built that’s made it to my office. Even tho the BIBs (168s with rs super tweeter on back) totally overwhelm the Pioneer/Piezo’s by the way they fill the room, he still prefers Pioneer/Piezo treble and overall warmer sound (personally, I don’t hear what he’s hearing other than the warmer balance). I find the B20 warm and veiled in presentation (which can be a good thing) and I really do like the B20 lots! But it’s not better than any Fostex I’ve heard so far.

That said, I always find another reason to build another kind of cabinet for the B20. It’s pretty cheap at $25… sounds very good… is totally non fatiguing (probably its best quality) and has a pretty big sound. I’m curious how EQing the top octaves sounds rather than using a helper tweeter.

BIB dims for the B20 can be found by clicking below.

http://www.zillaspeak.com/bib-pioneer.asp

It’s a pretty reasonable box compared to the other 8” drivers that are simmed but still a big cabinet. I’m so into the sound of the BIB all I want to do is build more (TB Bamboo all cut up but on temporary hold). But I wonder… if a BIB is too large for your application Kensai, perhaps a tall slim ported box built to fit your specific footprint might not be such a bad idea.

PioneerB20 sims in WinISD for larger ported/sealed boxes below:

http://www.zillaspeak.com/ZillaSpeakWinISDPioneerB20.asp

Pretty darn good extension in those larger ported boxes… I will check the port sizes tomorrow.

Godzilla
 
Well, Zilla, compared to what I'm used to, the B20 are easy to listen to and are more revealing. I've already heard a few minor things that wasn't really expecting from familiar tracks. You've mentioned repeatedly that they're a bit veiled and not as detailed as say TB Bamboos or Fostex anything, so I'm alot more convinced of they can do now that I have the comparison basis in hand now :)

As for the EQed treble, I did a bit of A/B engaging and disengaging my treble correction and it goes from sounding like its playing under a mattress to being airy, full and detailed. The only tweeters I have to compare right now are the B&G Neo3 PDRs currently in the living room, and they are a bit more clear and detailed, but that's only noticeable under critical listening which isn't my normal mode of audio consumption. The amount of "air" as we've discussed it is comparable. The main drawback of just EQing the top end back in seems to be that the response varies quite a bit over angle. Say its at 100% potential SQ at about 3-5 degrees off axis. At axis, its down to maybe 90%-95%. At 15 degrees, its down to 85%-90%. At 30 degrees its probably closer to 80%. Since they're on hinged baffles and I can get up and away from them, I listened a bit at close to 90 degrees, and they're basically dead there, say 50% SQ. However, if I just leave them angled the way they sound best in my chair and get up and leave the room, they tend to stay at 60%-70% as I move from room to room. The Neo3s are mounted at maybe 12"-14" from the floor, so they never really get past 90% of their potential simply due to the way I have to situate them, but they stay at about that level no matter where you sit to watch TV and never drop past say 80%, no matter where you move, into the kitchen or upstairs.

Really scientific, I know, but those are my impressions on the differences. A dedicated tweeter is going to get you a more stable image, better overall SQ as you move outside of your sweetspot. However, in my current application, nearfield with the ability to easily adjust angle at will, the B20s actually sound similar to the drivers from the living room rig, in these same baffles, but with a more detailed midrange.

Well, getting long again, but there's lots to rave over, especially given that these were free to me. As for enclosure, I'd really like to be that first guy to build some B20 BiBs, but if I'm going to do that, I'll want to couple them with the Neo3 (just a planar guy at heart, I guess) so that I've got a functional speaker outside of my specialized PC source gear. Besides, I've got a decent project idea for converting the living room cabinets into something . . . other . . . likely involving a Fostex 3"-4.5"er of some flavor and heavy duty 8"er crossed at 200Hz or lower. Suppose I'll post with pics if/when I manage to do either.

Kensai
 
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