I have done 1 set (for Kensai -- his review is here somewhere). I have 4 more i really need to get to.
Far too much work to be a viable commercial product, but an excellent technology demonstration.
dave
http://www.diyaudio.com/forums/showpost.php?p=1583642&postcount=30
Did not know that existed till you mentioned it.
Bud
Thank you gentlemen,
I agree with Dave that it is alot of work for it to be viable commercially. I am playing with it because I bought the drivers for very cheap ($25 for both including the voight pipes), because I would like to get as good sound of them as possible, since I really cannot afford any better drivers, but most of all it is a learning experience that may (or may not) be of some use to others. I love learning. I think that is reallythe main reason I am really doing it.
BudP,
I have read the tap test instructions before, and have even attempted to tap on the cone, but to be honest, I could not hear anything. Maybe I need to apply myself better. (Also the whizzer is kind of in the way of the swinging ( I usually hit on the backswing).
I agree with Dave that it is alot of work for it to be viable commercially. I am playing with it because I bought the drivers for very cheap ($25 for both including the voight pipes), because I would like to get as good sound of them as possible, since I really cannot afford any better drivers, but most of all it is a learning experience that may (or may not) be of some use to others. I love learning. I think that is reallythe main reason I am really doing it.
BudP,
I have read the tap test instructions before, and have even attempted to tap on the cone, but to be honest, I could not hear anything. Maybe I need to apply myself better. (Also the whizzer is kind of in the way of the swinging ( I usually hit on the backswing).
I made a small wizzer cone from regular white copy paper and attached it inside of the wizzer cone that's there and there's more treble coming from the driver. Not sure it it's better or worse but there is more treble. Also, holding different things in front of the driver produces more or less treble. I'm sure every driver will sound different by holding things in front of it. Then i bought a bunch of felt dots from the hardware store but have a feeling my temptation to fiddle with the driver will fade since it sounds pretty good on its own already. LOL. I also read about the tap test and tapped on the driver with a pen but really wasn't sure what i was listening for (maybe a ringing). Placing things into the center where the wizzer is seems to make the biggest change. Cutting out the dustcap and adding one of those wooden beaks will probably make a change in their sound and probably looks best cosmetically too.
Godzilla
Godzilla
A more serious tweaker could, of course, attempt to extend the pole and add shorting paths, or even add an additional magnet in repulsion to the pole , to ensure full motor strength and saturation.... It might be REALLY difficult to do well....... some of us may have gone down that road and decided it wasn't able to be done elegantly enough with what we tried...
Having never even heard this driver, I cannot comment upon it's use. However, my opinion is that if the item in question shows promise and continues to do so as changes are made, ones that have shown their worth in other circumstances, I will always continue the process.
The tap test is quite subtle. And, it must be performed in a quiet and calm environment. Use the tip of the pen that holds the calligraphy tips, it is perfect for this. Sit and idly tap up and down the cone face, letting the tip bounce back to get it off of the cone surface quickly. Use a light stroke and small movements, you want to just barely energize the surface.
As you tap in this radial fashion listen for what the decay does. Specifically listen for an odd sense of direction change. There will also be places where the tonal character changes, sometimes dramatically, from a thwuk to a clack. In other places the cone seems to go dead and suffer a sharp drop in radiated sound. These are all areas that affect the sound you hear when music is playing.
Concentrate on the directional bit first. This is the majore resonance node. You will find one very close to the edge of the shadow from the whizzer. Sometimes smaller in diameter, sometimes other than that, but always very near that diameter. After placing a pattern here you can revisit the other spots to find out how they have responded. If they have disappeared, good. Most likely, they have become more noticeable and will likely require a pattern of their own.
When a driver is finished, a tap test provides a smooth change in tone, across the radial from voice coil to surround, and a single direction pointing to the surround, without nulls, for the decay direction.
If you find a zone, out in the last 1/4 to 1/5 of the cone, that suddenly seems to be producing a louder sound, and it appears to be coming from the entire radius of the cone, rather than from just the spot tapped, you have found a Raleigh wave. These are nasty events. You can cure them.
Look back at he Fostex F200 A and the Emminence Beta 8 for method. Their posts are in the attached document. 8 inch drivers appear to be universal in their embrace of Raleigh waves. The outer 1/4 of whizzers that have a hat brim also have this problem. The cure for those is not yet finalized, though we are close enough that the remaining problems are not aggravating and are just barely noticeable on one or two individual piano notes.
Bud
The tap test is quite subtle. And, it must be performed in a quiet and calm environment. Use the tip of the pen that holds the calligraphy tips, it is perfect for this. Sit and idly tap up and down the cone face, letting the tip bounce back to get it off of the cone surface quickly. Use a light stroke and small movements, you want to just barely energize the surface.
As you tap in this radial fashion listen for what the decay does. Specifically listen for an odd sense of direction change. There will also be places where the tonal character changes, sometimes dramatically, from a thwuk to a clack. In other places the cone seems to go dead and suffer a sharp drop in radiated sound. These are all areas that affect the sound you hear when music is playing.
Concentrate on the directional bit first. This is the majore resonance node. You will find one very close to the edge of the shadow from the whizzer. Sometimes smaller in diameter, sometimes other than that, but always very near that diameter. After placing a pattern here you can revisit the other spots to find out how they have responded. If they have disappeared, good. Most likely, they have become more noticeable and will likely require a pattern of their own.
When a driver is finished, a tap test provides a smooth change in tone, across the radial from voice coil to surround, and a single direction pointing to the surround, without nulls, for the decay direction.
If you find a zone, out in the last 1/4 to 1/5 of the cone, that suddenly seems to be producing a louder sound, and it appears to be coming from the entire radius of the cone, rather than from just the spot tapped, you have found a Raleigh wave. These are nasty events. You can cure them.
Look back at he Fostex F200 A and the Emminence Beta 8 for method. Their posts are in the attached document. 8 inch drivers appear to be universal in their embrace of Raleigh waves. The outer 1/4 of whizzers that have a hat brim also have this problem. The cure for those is not yet finalized, though we are close enough that the remaining problems are not aggravating and are just barely noticeable on one or two individual piano notes.
Bud
P10 treated w/phase plugs, the B20 is hard to beat. Of course, there's alot of competition at the $300 or so per pair Dave would have to charge for them if he were going to sell them that way (there's alot of work to do on an 8" driver w/whizzer and phase plug), but if you're interested in investing some elbow grease rather than cash, it can totally be worth it.
Have had mine running just as mentioned in the old post Bud pulled up for almost a year now, and I've had absolutely no urge to upgrade them at all. Upstream is another matter, though, as every time I've made some improvement there, they've made the P10 B20s shine even brighter.
Kensai
Have had mine running just as mentioned in the old post Bud pulled up for almost a year now, and I've had absolutely no urge to upgrade them at all. Upstream is another matter, though, as every time I've made some improvement there, they've made the P10 B20s shine even brighter.
Kensai
Hi Kensai! The fact you have been listening to the B20s for so long is quite a compliment for a driver considering you can buy and build something else anytime you want. I too still listen to my pair (unmodified) and enjoy them too. And i do notice a sonic change when something is placed into the center of the wizzer... more treble response... and have a feeling the phase plugs from Dave go a long way in making the most of the B20s. Maybe i will get a pair too. They do so much right and so little wrong but:
"They sound very good for the money. If you put them next to another speaker, they may sound a little nasal/recessed in the upper midrange..."
I pulled the above quote from another thread regarding the Eminence Beta 12lta and feel the same way about the Pioneer B20. It sounds great until you compare it to something else that's better.
Question, do you still enjoy your B20's on the open baffles you made? Do you enhance bass with a subwoofer? Do you use a tweeter with your modified B20s?
TIA,
Godzilla
"They sound very good for the money. If you put them next to another speaker, they may sound a little nasal/recessed in the upper midrange..."
I pulled the above quote from another thread regarding the Eminence Beta 12lta and feel the same way about the Pioneer B20. It sounds great until you compare it to something else that's better.
Question, do you still enjoy your B20's on the open baffles you made? Do you enhance bass with a subwoofer? Do you use a tweeter with your modified B20s?
TIA,
Godzilla
Hey Zilla:
That's the nice thing, they're largely sins of omission. It's a driver that doesn't call attention to itself, and EnABL and high frequency improvements help with that. There was a large improvement after the dustcap came off. With dustcap in place it's rather boring, but Qtc dropped by almost 10% when I tested (did my tests in-box as it helps with consistency), and the driver opened up quite a bit.
EnaBl is dangerous though. It makes the coaxial tweeters stand out while the pioneer does an image disappearing act. Dotting a 3/4" dome will be a treat.....NOT!
Not........? Not so. Tis easy , painless, relatively quick and very useful.
Seriously, for most, just a ring at the base of the dome and one of the six block set ring sets on the dome tip and a central dot and a tiny nipple of PVA will completely disappear the tweeter. Plus you suddenly have both wider options in where exactly to put it, with respect to matching voice coils to voice coils for phase matching, and, the high frequencies become an intrinsic part of the music. You will no longer be aware of them as "high frequencies"
The wider placement choices include matching the voice coils, matching the tweeter tip to the main cone mid ring set, that kills the main resonance node, or matching the base of dome ring to the final ring set on the cone. All three will work well, with the best being up to your preferences or physical needs.
Multiway systems, done in EnABL, are so flexible and easy to use it is almost sinful.
Bud
Seriously, for most, just a ring at the base of the dome and one of the six block set ring sets on the dome tip and a central dot and a tiny nipple of PVA will completely disappear the tweeter. Plus you suddenly have both wider options in where exactly to put it, with respect to matching voice coils to voice coils for phase matching, and, the high frequencies become an intrinsic part of the music. You will no longer be aware of them as "high frequencies"
The wider placement choices include matching the voice coils, matching the tweeter tip to the main cone mid ring set, that kills the main resonance node, or matching the base of dome ring to the final ring set on the cone. All three will work well, with the best being up to your preferences or physical needs.
Multiway systems, done in EnABL, are so flexible and easy to use it is almost sinful.
Bud
I cut the dustcap off my B20 and will listen to the driver compared to the stock tomorrow side by side. It was easy to do. I will post my impressions... now i can begin thinking about phase plugs too. B20 may be a good driver to tweak since it's relatively inexpensive.
Godzilla
Godzilla
Isn't that what people have been saying?!
🙂
Enjoy the trip, it has a LOT of improvement possibility.
I wonder if these drivers would benefit from complete whizzer removal and crossed over to a tweeter somewhere around 5 - 6 kHz i.e. a wideranger rather than a full ranger operating in break-up mode.
Any thoughts / experience?
Any thoughts / experience?
at 5-6k they're already well into breakup mode. Not sure how high they'd go sans whizzer, but we may well find out, I do, after all, have a quad of these for the very purpose of experimentation.
Without the dustcap the driver sounds different. It sounds 'airier' and less cupped hand over mouth. Overall it sounds lighter on its feet... less dark... maybe a bit thinner too. I am not sure the treble is more extended but what i hear sounds clearer. The character of the sound changed from dark to light. The difference is easily heard on vocals or anything with treble. I may be hearing a bit of a spitty sound too without the dustcap. More listening needed for sure. I wish i just poked a hole first but the dustcap is gone. I do think a phase plug will change things up even more based on just holding something in front of the wizzer cone. I'm happily tweaking a single B20 and will compare side by side with stock. I like how the 'cupped hand' sound has gone very much (along with the dustcap). Yes badman... you said it all along... meanwhile i kept saying they are 'plenty good' stock... i may have been wrong.
Godzilla
Godzilla
I don't need validation, your reluctance to mod them always just seemed odd to me, given that you're a dyed-in-the-wool DIYer. One of the great things about the B20 is that if you mod it to death.... they're not exactly expensive, you can start fresh!
Enabling them made them very excellent but the coaxial supertweeter (which wasn't a problem before enabl) is now very much a hotspot. I'm going to try enabling it too, but jeesh, them's some tiny dots!
Enabling them made them very excellent but the coaxial supertweeter (which wasn't a problem before enabl) is now very much a hotspot. I'm going to try enabling it too, but jeesh, them's some tiny dots!
Perhaps another experimenter will do the hole-in-the-dustcap thing. I also wonder how it would sound, since my Fostex 167's go that way.
if one were to do it, they'd likely want to poke a bunch of holes, so as to provide sufficient ventilation to relieve pressure, and avoid any turbulence 'whistling' through an undersized hole.
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