Hi All,
I ran sims on the Pioneer B20 again. I love experimenting with this driver.
http://www.zillaspeak.com/pioneerb20-3cubox.asp
3 vented boxes all tuned to 34hz and one closed box.
What I want to understand better is why the three different sized vented boxes appear to give best results when tuned to 34hz? Raising the tuning frequency on the smaller box (for example to 40hz) produces too much of an exaggerated bass response that I think will muddy the sound. The vented boxes are tuned below the drivers Fs of 43hz.
I’ve always listened to this driver in a sealed cabinet and like the sound. I feel it offers something different than some of the forward sounding drivers we use around here.
3.0 Box - round port 3 x 3” long (slot 9.25 x 1.5 x 6.64)
2.5 Box - round port 3 x 4.25” long (slot 9.25 x 1.5 x 8.75)
2.0 Box - round port 3 x 6” long (slot 9.25 x 1.0 x 7)
Truly,
Godzilla
I ran sims on the Pioneer B20 again. I love experimenting with this driver.
http://www.zillaspeak.com/pioneerb20-3cubox.asp
3 vented boxes all tuned to 34hz and one closed box.
What I want to understand better is why the three different sized vented boxes appear to give best results when tuned to 34hz? Raising the tuning frequency on the smaller box (for example to 40hz) produces too much of an exaggerated bass response that I think will muddy the sound. The vented boxes are tuned below the drivers Fs of 43hz.
I’ve always listened to this driver in a sealed cabinet and like the sound. I feel it offers something different than some of the forward sounding drivers we use around here.
3.0 Box - round port 3 x 3” long (slot 9.25 x 1.5 x 6.64)
2.5 Box - round port 3 x 4.25” long (slot 9.25 x 1.5 x 8.75)
2.0 Box - round port 3 x 6” long (slot 9.25 x 1.0 x 7)
Truly,
Godzilla
I've been going round and round with the options for my two primary rigs (office and living room), and I find that I can't really justify the cost of Fostex drivers, and can't really afford the lumber or space for any of the more interesting enclosures.
My wife is finally excited by the sound of something new. She's a music teacher, so you figure she can hear the difference between various bits of gear, but up until the sound of the B20s grabbed her, she apparently never "wanted" to and would always say, "it sounds fine . . . why do you keep messing with it?" I think its that fun, furry sound you attribute to it that got her attention. I like it, too, but I'm actually more impressed with the greater transparency and detail they offer over what I've been using (even though I know you say they're veiled compared to the Fostex). I could appreciate even greater transparency and detail, but I don't think I would like the loss of completely fatigue free listening (I do lots of headphone listening late at night, and my Grado SR80s, while somewhat more detailed, can be noticeably fatiguing after an hour or so). So, anyway, looks like the B20s are going to become staples in my house.
I want to see how they handle in my sealed cabinets in the living room with my B&G Neo3PDRs on the top end. If that goes well, we may need to order another pair. For the office, I'd like to come up with some sort of enclosure that A) I can afford and B) will let me back off on my EQing of the bottom end significantly, if not altogether. Even if I keep these simply fullrange and EQ the top in, they would make good sometimes surrounds for the living room (just run the wires and hide them to where they can be quickly fished out for "special" occassions).
I'm thinking of using 8"x48" lumber for the front/back/top/bottom so I can stain it to match all the rest of the wood in the house, and then use 12"x48" particle board for the sides which I could spray black or maybe some complimentary fleckstone sort of finish. That would give me a volume of around 2.25'^2. I was also thinking of putting the slot rear firing but up at the very top, just above the driver (as I would want the driver at about 42"), assuming I decide to go BR over sealed. If I decide to go sealed, probably need to go smaller, so might use 8" lumber all around for about 1.4'^2 or even 6" sides for just a hair under 1'^2.
The larger one with a bit of space locked out at the bottom for sand or something to weight it would be very close to your sim. I'll just play with it a bit more in WinISD, but eventually, I've got to build something, right?
Kensai
My wife is finally excited by the sound of something new. She's a music teacher, so you figure she can hear the difference between various bits of gear, but up until the sound of the B20s grabbed her, she apparently never "wanted" to and would always say, "it sounds fine . . . why do you keep messing with it?" I think its that fun, furry sound you attribute to it that got her attention. I like it, too, but I'm actually more impressed with the greater transparency and detail they offer over what I've been using (even though I know you say they're veiled compared to the Fostex). I could appreciate even greater transparency and detail, but I don't think I would like the loss of completely fatigue free listening (I do lots of headphone listening late at night, and my Grado SR80s, while somewhat more detailed, can be noticeably fatiguing after an hour or so). So, anyway, looks like the B20s are going to become staples in my house.
I want to see how they handle in my sealed cabinets in the living room with my B&G Neo3PDRs on the top end. If that goes well, we may need to order another pair. For the office, I'd like to come up with some sort of enclosure that A) I can afford and B) will let me back off on my EQing of the bottom end significantly, if not altogether. Even if I keep these simply fullrange and EQ the top in, they would make good sometimes surrounds for the living room (just run the wires and hide them to where they can be quickly fished out for "special" occassions).
I'm thinking of using 8"x48" lumber for the front/back/top/bottom so I can stain it to match all the rest of the wood in the house, and then use 12"x48" particle board for the sides which I could spray black or maybe some complimentary fleckstone sort of finish. That would give me a volume of around 2.25'^2. I was also thinking of putting the slot rear firing but up at the very top, just above the driver (as I would want the driver at about 42"), assuming I decide to go BR over sealed. If I decide to go sealed, probably need to go smaller, so might use 8" lumber all around for about 1.4'^2 or even 6" sides for just a hair under 1'^2.
The larger one with a bit of space locked out at the bottom for sand or something to weight it would be very close to your sim. I'll just play with it a bit more in WinISD, but eventually, I've got to build something, right?
Kensai
Also still thinking about an inverted taper TL using 4' lumber. I've also noticed that this driver likes to be tuned to 34Hz, so I'm wondering if maybe a TL tuned to 34Hz would be best. In a straight line, that would be about 99-100", so the taper needed would be minimal at best. Possibly not even needing the fold board to be angled at all, just placed slightly farther than halfway back in the box. Thoughts?
Kensai
Kensai
Larger ports are supposed to sound better than smaller ones, right?
I was playing around with the B20 in WinISD last night and modeled a few enclosures build from 8" and 12" lumber (~2.26 total internal volume) where the port ran the entire length and width of the back wall, the internal volume mating to the vent at the bottom and the vent firing rearward into the room at the top. I don't have any handy way to post those right now, but I found similar results (and yes I was careful to recalc the internal volume taking out the space of the vent and the extra board creating it into consideration). 3"x8"x43.5" vent tuned to around 25 and exhibited little boost but the beginnings of an extended bass shelf crossing 20Hz round -12dB. 2.5"x8"x44" vent tuned to ~30Hz with that characteristic "round" shaped rolloff. 2"x8"x44.5" vent tuned to a little over 35Hz had a bit much boost up around 60Hz than I would think appropriate.
These would look alot like a folded TL internally. Would that change the way they work to where the vented sims are no longer accurate? Would these sound noticeably better than something using a shorter, smaller vent?
Kensai
I was playing around with the B20 in WinISD last night and modeled a few enclosures build from 8" and 12" lumber (~2.26 total internal volume) where the port ran the entire length and width of the back wall, the internal volume mating to the vent at the bottom and the vent firing rearward into the room at the top. I don't have any handy way to post those right now, but I found similar results (and yes I was careful to recalc the internal volume taking out the space of the vent and the extra board creating it into consideration). 3"x8"x43.5" vent tuned to around 25 and exhibited little boost but the beginnings of an extended bass shelf crossing 20Hz round -12dB. 2.5"x8"x44" vent tuned to ~30Hz with that characteristic "round" shaped rolloff. 2"x8"x44.5" vent tuned to a little over 35Hz had a bit much boost up around 60Hz than I would think appropriate.
These would look alot like a folded TL internally. Would that change the way they work to where the vented sims are no longer accurate? Would these sound noticeably better than something using a shorter, smaller vent?
Kensai
Mainly because I've read statements to that effect over and over. Also, if tiny ports sounded okay, why wouldn't we all be using short half-inch ports on everything? Then, of course, there's the fact that WinISD shows widely varying first port resonances depending on size (the real life effect of which I am entirely uncertain of at this point).
I would think (and this is unsupported on my end by exeriential data), that the larger port diameter would decrease port noise (which I have been able to hear, regularly with many ported units, none of which I have owned). What are your thoughts on the subject?
Kensai
I would think (and this is unsupported on my end by exeriential data), that the larger port diameter would decrease port noise (which I have been able to hear, regularly with many ported units, none of which I have owned). What are your thoughts on the subject?
Kensai
Let's see if I get this right --->
The good thing about small ports is that they load the woofer really well and (mostly) help control the excursion. The bad thing is that at higher listening levels the port air velocity becomes too high and you can start to hear them "chuffing". All ports big or small will unload the woofer (bad) at very low fequencies.
The good thing about small ports is that they load the woofer really well and (mostly) help control the excursion. The bad thing is that at higher listening levels the port air velocity becomes too high and you can start to hear them "chuffing". All ports big or small will unload the woofer (bad) at very low fequencies.
Finally got around to trying these in my old Yamaha NS-6390 cabinets (really the same as the NS-6490 cabinets in the living room except for the costmetics, and even then . . .). Been putting it off because I was too lazy to cut, strip and terminate some wire for the internals.
Anyway, put up on stands so they were nearly identical height as they were in OB, lets just say they sounded funny. Sealed, they sounded a bit congested through the mids and then far too resonant in the bass, though not really reaching much deeper than OB. Pulled the tweeter (which I wasn't using, just left in to keep the cab sealed), and slotted an ~2"x8" tube for a port (tuning to the high 20s, I believe). That gave me flabbier bass, same congested mids, but really only slightly more extension than sealed (pretty much the same sealed or ported). Main thing that I really didn't not like was that the bass seemed to over energize the room(s). I could get up and leave the room and by the time I was far enough away for the bass to start rolling off due to distance or walls, that was all that could be heard. This means that even a little bass was basically full level in both of the bedrooms sharing the same floor as the office ;-p Anyway, this is a very nearfield setup, and there's really no way to negate all the "bad" this generated. Think I'm addicted to/stuck with OB or possibly BiB sound for that room.
So, since I was on a roll, I went ahead and swapped them out into the NS-6490 cabs in the living room (again having to strip and reterminate wire). These cabs had already been modded to contain B&G Neo3PDR tweeters (with back cups removed) which were running from a 2.2uF cap above the Yamaha 8" woofer running full range (which in OB rolls off a full octave lower than the B20 on the high end, and even with massive EQ could never be full range). These cabinets are laying on their sides in the outer lower compartments of my large oak entertainment center so centered about 10"-12" from the floor. Not ideal as we'll see.
First impression was very, very disappointing. Just didn't sound right at all. So I turned off all the limited EQ on the old Pio 411 receiver down there (Loudness control, Tone control, etc.). Got the bass right pretty quickly (very similar to the Yammie 8"er, which is plenty low for us in this setting; we get a ton of room gain here), but there was a hole in the lower treble. This was Zilla's admonition that the B20s are dull off axis come to roost. My only option was to hook the Neo3s up to 4.7uF caps that originally ran the mids for the NS-6490. This got the hole filled, but now there is congestion in the upper mids/lower treble. This isn't that bad, so we're living with it for the moment, see how it grows. The next step would be to find a cap value inbetween and try that out.
On more extended listening, the congestion up high is less noticeable when you're not listening critically, but the B20 is definitely more detailed than the Yammie 8"er. Just passing through the room while my 4-year-old was watching Madagascar, and there was a scene that I thought was just dialog, but there was some music playing very softly in the background, as if from some PA system in the scene itself, that I had never heard before, and that detail grabbed me. Also listed to alot of Pirates of the Carribean music over the weekend, too, and cello sounded fantastic.
This setup is just probationary. In the living room, all the issues I had nearfield are either good things (cabinet resonance, which activates resonance in our entertainment center giving us good bass down to 35Hz or so) or are much less noticeable (midrange congestion). We'll see how it goes.
One point this brings up in my mind is the issue of whizzer cones and off axis listening. The Yammie 8"er is just a standard cone with an inverted hard paper dustcap, yet I'm perceiving higher frequency extension at the listening position than with the B20 which is a solid octave better up top when at ear height in the sweet spot. Does this mean that non-whizzered drivers will generally give better off axis performance in the upper octaves? Would something like Fostex FE206/7/8 or FF225K give better performance up top in this situation? What about if the B20s were to be phase plug modded or possibly de-whizzered entirely?
Kensai
Anyway, put up on stands so they were nearly identical height as they were in OB, lets just say they sounded funny. Sealed, they sounded a bit congested through the mids and then far too resonant in the bass, though not really reaching much deeper than OB. Pulled the tweeter (which I wasn't using, just left in to keep the cab sealed), and slotted an ~2"x8" tube for a port (tuning to the high 20s, I believe). That gave me flabbier bass, same congested mids, but really only slightly more extension than sealed (pretty much the same sealed or ported). Main thing that I really didn't not like was that the bass seemed to over energize the room(s). I could get up and leave the room and by the time I was far enough away for the bass to start rolling off due to distance or walls, that was all that could be heard. This means that even a little bass was basically full level in both of the bedrooms sharing the same floor as the office ;-p Anyway, this is a very nearfield setup, and there's really no way to negate all the "bad" this generated. Think I'm addicted to/stuck with OB or possibly BiB sound for that room.
So, since I was on a roll, I went ahead and swapped them out into the NS-6490 cabs in the living room (again having to strip and reterminate wire). These cabs had already been modded to contain B&G Neo3PDR tweeters (with back cups removed) which were running from a 2.2uF cap above the Yamaha 8" woofer running full range (which in OB rolls off a full octave lower than the B20 on the high end, and even with massive EQ could never be full range). These cabinets are laying on their sides in the outer lower compartments of my large oak entertainment center so centered about 10"-12" from the floor. Not ideal as we'll see.
First impression was very, very disappointing. Just didn't sound right at all. So I turned off all the limited EQ on the old Pio 411 receiver down there (Loudness control, Tone control, etc.). Got the bass right pretty quickly (very similar to the Yammie 8"er, which is plenty low for us in this setting; we get a ton of room gain here), but there was a hole in the lower treble. This was Zilla's admonition that the B20s are dull off axis come to roost. My only option was to hook the Neo3s up to 4.7uF caps that originally ran the mids for the NS-6490. This got the hole filled, but now there is congestion in the upper mids/lower treble. This isn't that bad, so we're living with it for the moment, see how it grows. The next step would be to find a cap value inbetween and try that out.
On more extended listening, the congestion up high is less noticeable when you're not listening critically, but the B20 is definitely more detailed than the Yammie 8"er. Just passing through the room while my 4-year-old was watching Madagascar, and there was a scene that I thought was just dialog, but there was some music playing very softly in the background, as if from some PA system in the scene itself, that I had never heard before, and that detail grabbed me. Also listed to alot of Pirates of the Carribean music over the weekend, too, and cello sounded fantastic.
This setup is just probationary. In the living room, all the issues I had nearfield are either good things (cabinet resonance, which activates resonance in our entertainment center giving us good bass down to 35Hz or so) or are much less noticeable (midrange congestion). We'll see how it goes.
One point this brings up in my mind is the issue of whizzer cones and off axis listening. The Yammie 8"er is just a standard cone with an inverted hard paper dustcap, yet I'm perceiving higher frequency extension at the listening position than with the B20 which is a solid octave better up top when at ear height in the sweet spot. Does this mean that non-whizzered drivers will generally give better off axis performance in the upper octaves? Would something like Fostex FE206/7/8 or FF225K give better performance up top in this situation? What about if the B20s were to be phase plug modded or possibly de-whizzered entirely?
Kensai
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