| nebojsa |
| Tonight I was about to order a set of pioneers as well as dayton Ndf20fa tweeter for either a half chang or full version. Since they are on sale, was just wondering if a bipole has ever been tried. Perhaps, sealed enclosure sucha as zilla used but as bipole. Or ml tl bipole? Any thoughts? Seriously tempted to order more. |
|
|
| Scottmoose |
| You'd need a big cab. or heavy Eq if you want any LF out of them. |
|
|
| Kensai |
Order more. Go surround in sealed floor standers :)
Or maybe go dipole in OB. I ran that way for a long time till I finally figured out what that niggling little issue with them was in the back of my mind. Being whizzered, the back wave isn't even remotely similar to the front wave, so their interaction is alot more rough and weird than say a nice, smooth woofer with inverted dustcap or even better, a planar driver. So, what I propose is 2 B20s (and possibly 2 tweeters) per speaker. Mount one as normal and mount the other reversed, beneath, that way you've got a front and a back wave launching from either side of the baffle. These are not ideal for OB, so you'll likely just be getting into the 70s with these without EQ. I used a pretty serious amount of EQ and was able to get good response into the 50s, as well as eliminating the need for tweeters.
Oh, and I prefer the 5/8" Dayton dome, personally.
Have fun.
Kensai |
|
|
| drwho |
Scottmoose/Kensai
When you say EQ, are you talking about using an external equalizer and adjusting the low frequencies via the equalizer.
Or do you mean something else?
Thanks |
|
|
| Scottmoose |
| Yes, if you can't use a big cabinet. |
|
|
| GM |
Greets!
As already noted, these require big cabs to get the max gain BW out of them, so dual B20s require around 8 ft^3. They make fine MLTLs IMO, but they also work well in a prosound alignment (AKA max flat impedance AKA Wayne Parham's 'PiAlign') if you either don't need to get the bottom 1 - 1.5 octaves due to using a sub and/or you have the ability to pull them out away from walls/corners enough to get some LF gain without excessive mid-bass boost, which of course is desirable for a bipolar alignment. Since these alignments do a good job of protecting the driver down to Fb, they can typically be played at a higher average SPL and/or boosted or minimally compressed signals if you have plenty of clean power on tap, up to around 200 W for a bipole B20.
The downside from my POV is that its typically low tuning and reduced Vb means it doesn't yield what I consider an optimum MLTL alignment due to its excessively high aspect ratio the way I calc them, typically putting the driver too low when optimized without adding a short stand or lower ballast cavity. With the advent of MJK's software and how pleased folks are with aspect ratios Vs driver location that I've historically avoided from a theoretical POV, it may be much ado about nothing, so you may want to try this ~ear height variant if a small footprint is required, though of course it will require some form of wide stand to counter-balance its top heaviness:
L = 46.25"
WxD (CSA) = ~112.11"^2
zdriver = 9.25"
zport = 43.25"
dport = 3.5"
Lport = 3"
All dims inside (i.d.) and approximate, 0.2 lbs/ft^3 polyfil stuffing density simmed.
GM |
|
|
| Godzilla |
http://www.zillaspeak.com/pioneerb20-3cubox.asp
The yellow line is the closed box. Looks like you can get more bass from the B20 but listening to the sealed box i do not feel it's lacking especially when compared to smaller boxes using Fostex or TB drivers. The B20s sound fuller. I always liked this driver and think it's worthwile to own. Some have been disappointed with it. But once a tweeter (pick your poison) is dialed in, it does sound very good. Plus, you don't worry much about the driver getting pushed in and destroyed since it's pretty cheap compared to similar Fostex. I feel the B20 offers its own set of pro's compared to some of the Fostex cons... but Fostex are better overall IMO. Certainly a different sound. If you want a relaxed, laid back sound go for the B20 (and miss some detail and speed). Fostex offers the detail and speed but their presentation is more forward. Enjoy! |
|
|
| nebojsa |
Thank you guys for all of your responses, I will be ordering Pioneers tonight.
GM mltl you specified is for a bipole, correct? The foot print is not large, which is the way I would like it. Sorry, I've read it number of times but still get confused on terms. Thank you for your patience. |
|
|
| GM |
Correctomundo!
OK, what's not clear?
GM |
|
|
| Scottmoose |
Probably the dimensions, if he's not used to them.
OK: short translation[s]. Dims. will be internal.
L = 46.25" (cabinet height)
WxD (CSA) = ~112.11"^2 (cabinet cross sectional area, i.e. if you multiply width x depth, this is what you'll get.)
zdriver = 9.25" (distance of the driver centre from the internal top of the cabinet, or, more accurately, from the sealed end of the line)
zport = 43.25" (distance of the port centre from the top of the cabinet / sealed end of the line)
dport = 3.5" (circular port diameter)
Lport = 3" (length of port) |
|
|
| norman bates |
I liked much...............
I found them a little honky, part due to qtc.707 with no stuffing (6ft3 = qtc .577 no stuffing 1' deep x 2' wide x 3' tall, driver up against to of the box work much much better), and that tall whizzer.
Be sure to put loose cotton balls behind whizzer (It helps)
Run by themselves they sounded good to me with some help from a 10 band eq......... I trimmed off 1/4 to 1/3 of the whizzer....... I needed more eq (8khz and 16khz bands maxed on eq)..... Not the crispiest sound but nicer (less honky) than the full whizzer......... Then I cut the whizzer off, no honk, and zero highs even with equalizer help...............Learned my lesson there.
Some have luck with damar........
I've always wanted to try planet10 phase plugs but to me I'd pay $30 for a pair, no way in *ell I'd pay $50 for them.........
fostex would have better highs.
Tang band w3-871s blew it away for midrange clarity.
But the b20 has some bass that a 3-4" has trouble with.
And plays louder with less harmonic distortion.
My ears liked the bit of 2nd order harmonic distortion.
Made it sound like it had some punch.
Godzilla has luck with piezo.
My giant killer was an active crossover at 5khz/24db LR having a b20 and piezo (that rings at 4.5-5khz) ....even had the unmodified tall whizzer........
Norman |
|
|
| nebojsa |
| Thank you GM and Scott, I get it. What type of internal cables do you recomend? |
|
|
| Kensai |
The phase plugs are worthwhile, and with the drivers down to $20, they only make the whole package $45 per driver. My B20s have had the full P10 modification done to them (the only pair of the kind in existence as far as I know). I'd don't the phase plug mod with plugs from P10 quite awhile before getting the puzzle coat and EnABL mods done, and that was after having used them daily for almost a year stock.
The phase plugs were the cheapest, easiest and most bang for buck part of the whole modding epic, and easily recommend that part if you've got a bit more money to burn on drivers. Even at full price ($50/driver) they compare favorably against TB and Fostex drivers of similar price (they have alot more bass and are alot more forgiving of enclosure or the lack thereof), and you can't get another 8" full ranger for anywhere near the price (excluding, of course, the 8" Goldwood).
Being as that may, the cheapest part is just ordering them on sale right now. A stock B20 sounds way better than no B20 ;) When I received my pair as a present for christmas '06, I spent the first couple weeks kicking myself over having stuck with my similarly priced though locally available 6"x9" bicone Kenwood drivers, that at the time I had thought sounded pretty good. My reluctance to order drivers had wasted nearly two years of quality yet inexpensive DIY time. Advice to everybody that isn't already firmly entrenched in this hobby -- grab at least a pair of these now while the getting's good. They'll probably beat everything you have on hand now, they'll provide you with a very wide array of DIY experimentation opportunities (just think of the cabinets and driver mods that could be done), and over time, after your DIY budget has long pulled away from these drivers, you may find yourself coming back to them. At the very least they make great units for secondary system, surround speakers playing second fiddle to more expensive efforts, systems for the kids' bedrooms, gifts for family and friends, hand-me-downs, etc.
Enjoy!
Kensai |
|
|
| Scottmoose |
| quote: | Originally posted by nebojsa
Thank you GM and Scott, I get it. What type of internal cables do you recomend? |
Whatever you feel like, so long as the gauge isn't unreasonably small. 20ga or larger will be fine. |
|
|
| norman bates |
kensai,
you are right...........I have found myself coming back to them.........after a few years..... but active with piezo...... I don't like the way they honk..........bad whizzer...........
and I've been following most words you've typed.
I guess I just have a hard time with the price of the phase plugs.....
and I do like more bass than a 3" can beliver but detest most circuitry.
Norman |
|
|
| Kensai |
Norman,
Yeah, the price of the plugs is a bit offputting since it doubles the price of the driver. I totally get that. I spent months trying to finds a way to fashion my own or repurpose something else to do it for me, but that was a total waste of time and patience. When Dave said he had plugs, meant for a Fostex driver but fit for the B20s as well, I just broke down and did it.
After I stopped kicking myself about not buying B20s earlier than I'd gotten them, I started learning to live with them, and yeah, they honked and they rasped along at the top end in a way that I could never quite make sound pleasant using the considerable EQ abilities of my Emu 0404 sound card. I just had to keep reminding myself what I had been living with before, but every once in awhile I'd be listening to a piece and really digging in when they would throw me a curve and then I'd be back to "how can we mod these things to fix them". Researching and asking questions around the boards basically got me down to a few thing, mainly, damar or puzzle coat for the whizzer and then phase plugs. Coating the things was basically irreversible, so it would suck it that damaged things. The only problem with plugging was the initial dustcapectomy. I'm handy with a knife so so that was the way I was leaning.
Anyway, the phase plugs really fixed the honk. In effect they push that honking distortion up an octave, effectively rendering it inaudible. Seemed to smooth just about everything out, not to mention giving me a solid 2-3Hz extra at the bottom, mostly due, it seems, to removing the resistive pocket of air under the dust cap. It also turned out that the dust caps on these are easy to remove and don't really put the voice coil or leads in danger. It seems like another no brainer in retrospect, but you know annoyingly clear hindsight is.
Just my $.02
Kensai |
|
|
| norman bates |
Kensai "Anyway, the phase plugs really fixed the honk"
good to hear..........that honk made sax's sound more real, adding bite, but bothersome on voice to me otherwise.........never bothered me b4.......then i heard it...then i always heard it.......grr.........
I'm sure the honk is due to the extermely tall whizzer making the highs off the dustcap bouncing around in there untill they tumble out. But the driver also honked more in a smaller box than qtc.577 I'm thinking the box reflections just added with the whizzer honk so now we have a boxy-honky sound.
The resonance under dust cap, common problem. Seen a tweek of the .89 wonders where they poked a hole in the dust cap with a soldering iron, graphs too. Some drivers are worse off with this tweak tho.
In the b20's defence, it taught me how bad my electronic crossover actually was. I crossed the b20 at 200hz (24db LR) to double 15's.... The highs were awfull, gritty, plain horrible compared to no active crossover, just dvd player into amplifier (with volume controls) into pioneer b20. And it allowed me to hear echos coming from a great pa horn I was borrowing (bless my friend). Later I tried running it full range but had huge basement and couldn't tolerate bass modulation to voices sitting 7' away.......
Unsure on the puzzlecoat but have read the enable stuff.....
maybe another day.
Have to think if I want to order a couple with phase plugs.
Currently I want to make a "time alignment demonstrator" to bring to local diy show. Using 2 full range drivers (seperate boxes, peerless v-line) put cap on one and inductor on the other, move back and forth, and let people hear what a time aligned/phase aligned system sounds like. Tweeter would work better but need to trap out resonance and get tweeter exact in level. Using 2 full rangers with benign impedence curve makes for easy network
I realize time is money, as is the frustration and intellectual work it takes for design, tweaking, knowledge, and experience.
Since I'd cross them at 5khz, I'd trim 1/4 of the whizzer off, worked for me.
Seeing the recent price hikes (falling US dollar, gas increase, materials increase) may push more diy and used than ever b4.
Norman |
|
|
| mightym |
Kensai,
Please forgive my confusion.
beyond he dustcapectomy, and the Phase plugs, did you also give your drivers a " whizzerectomy " ?
I am trying to put an HT system together without spending too much, would you think that B-20 BIB's with phase plugs, and puzzlecoat, satisfactory for front mains?
John |
|
|
| Godzilla |
>>> would you think that B-20 BIB's with phase plugs, and puzzlecoat, satisfactory for front mains?
I'd imagine it would also need a tweeter. |
|
|
| Cambe |
Hello,
What are the alternatives if the 3.5 inch port diameter(inside) isn't available?
:cool: |
|
|
| Kensai |
No whizzerectomy. They will require either EQ for the top end (yes this really does work, and it sounds pretty darned good; has very poor off axis response, though, unless you have phase plugs), or tweaters capped in with 2uF or smaller. I'm using mine in my livingroom now, in large sealed bookshelves (so about 21.3 L + a pretty serious amount of soft, open cell foam) crossed to the stock Yamaha tweeters originally in that box with the stock 2.2uF caps. They really came into their own here. They really want a box, and they sound really clean in sealed. In my application where the driver center isn't more than 9-10 inches from the floor and the effective baffle width is about 7' since they're in the outer, lower compartments of a huge oak entertainment center which also has about a 2" airspace below the bottom panel (which is cut from a single sheet of oak plywood) which is open in the back, I'm getting pretty solid to 35Hz and useable down below 30Hz with nothing more than my crappy old Pioneer receiver's "loudness" control set to ON. These need better tweeters, but I've been lazy/busy lately . . . gonna need to cut or find something I can screw down to one of the openings and then mount my Dayton 5/8" domes into, and that just sounds like alot of work right now ;-p
Kensai |
|
|
| Scottmoose |
| quote: | Originally posted by Cambe
Hello,
What are the alternatives if the 3.5 inch port diameter(inside) isn't available?
:cool: |
Just use a rectangular vent with the same CSA. Make sure the HxW dimensions of the vent don't exceed a ratio of 1:9 |
|
|
| Nihilist |
I've owned/used B20's and wasn't very happy with them. Pretty much all the stuff you guys have said is what I found wrong about them .
Dustcap resonance= nasal/congested mids
Treble that was desperetaly in need of a tweeter
Bass that was fairly decent, but rather soft in it's presentation , no "whack" or "snap"
I had them installed in a 7' line that was not tapered, and was approximately the same cross sectional area as the cone.
I tried them Bipolar in the same cabinet, but the port/terminus was too noisy ( not enough area ? )
Based on my experience with this driver, I would suggest:
1. Remove the dustcap, it sounds like HELL.
2. Solder the Aluminum voice coil former's gap, so it acts as a shorted turn. This will reduce inductance and help the treble response.
3. Install either a copper or aluminum phase plug. This will also help reduce the driver's inductance and help treble response. Be creative, there are plenty of things you can find to use for a phase plug.
4. Line the inside (facing the cone) of the frame's legs/spokes with felt or somesuch , this will help reduce the first reflection and help clean up the mid/treble.
5. Damp the outside of the frame with ropecaulk/ductseal/etc. This will help reduce the baskets ringing.
6. Perhaps some type of cone treatment if these other mods haven't fixed it's ugly sound.
I have little-to-no love for the B20. When you consider what must be done to it for it to work decently, it really loses it's appeal and value.
Why not just start with a better driver , do the same mods, add a whizzer, and have a better speaker for about the same cash ?
Silver Flute 6 1/2" shielded sure looks sweet , the 8" non shielded looks good , too.
Tang Band 6 1/2" looks pretty sweet. Add a whizzer and your set. It's even about 91-92db.
There are plenty of drivers I would choose over the B20.
Sorry if I've offended any B20 fans. My experience with them wasn't very good. I will say they are QUITE durable.
Just my $2.00 worth.
...........................................Blake |
|
|
| mightym |
My intention was to use the PE push-in tweeter that every one seems to like with this driver.
I was going to purchase several caps to experiment with where they roll in.
No offense to Dave at P10, but I was going to turn my own phase plugs. The basic ideas is DIY, after all isn't it?
You cannot count the cost of your time, when it is spent in a labor of love.
John |
|
|
| mikje |
Scottmoose,
Did you use any damping in these? If so, what and how much. I'm seriously thinking about a pair of these for a Velleman chip amp, at least until my next chip amp. Thanks for sharing your experience and know-how!
Mike |
|
|
| Scottmoose |
| Blast. Knew I'd forget to post something. Yes, 0.45lbs ft^3 of hollow fibre material in the first 1/3 of the line, or (better) line the back, top & one sidewall with ~1in thick damping material. Adjust to taste / suit your room & system from there. |
|
|
| Ed LaFontaine |
Cambe,
If the port is still an issue, you can find 3.5" dia. pvc conduit across your electrical supply counter. |
|
|
|
