OB: Dark Star Shootout - Betsy vs. B200 - Page 2

serenechaos · 28th October 2009, 02:32 PM

No, you probably don't want to know what Tull is about...
I've loved that album since high school though.

Can I bring a 160Hz azurahorn by, to set in front of a Betsy so you can really hear it?
(evil grin)

pjanda1 · 29th October 2009, 05:04 PM

There isn't much I can add here, as I'm glad that you're enjoying them!

RJBond and I talked a bit via email about messing with the Qts via wire and resistors. I am testing some prototype TL's (for the BetsyK). Initially I was amazed at how much bass they were producing, but it seemed over the top. I swapped the Cat5 speaker cable I had in the system for the OB's to my reference wire (Jon Risch's cross connected Belden 89259 coax recipe) and I couldn't believe the difference. This is what I expected to hear. Most wire is cheap, and certainly worth playing with. I often feel that the OB's are a little "plump" sounding. I need to try the bigger wires.

You noticed that the Betsy's smoothed out pretty quickly, which is partially the driver, but greatly due to the application. As OB's don't restrict excursion at all, the driver sees much more action than it would in a boxier application. I try to break all my drivers in in free air or on OB's. The little TLs I just erected for the BetsyK's, for example, keep excursion well controlled, so the drivers spent a day and a half getting pounded on my test bench.

I have used rope caulk, but on a recommendation from someone here, I find that less rigid driver mounting sounds better. It doesn't make any sense to me, but I get a better midrange with closed cell foam and mounting bolts backed off a 1/4 turn from snug. Whatever you do, keep it the same for both drivers so the comparison will be fair!

I haven't played with it, but folks also seem to experience significant changes with stuff applied to the back of the baffles. I suspect the difference will be lessened when you leave the big wing straight out. The Darkstar guys seemed to like cork. A gent just posted on my blog that he likes "Frostking Duct Insulation".

I choose a steel basket for many reasons. I want to maximize price/performance, but also make a driver that didn't look like it prioritized eye candy over engineering. The Visaton will be really well built, but not all drivers are as carefully assembled as the Betsy! I honestly can't hear a difference with the basket. Those that are worried about it can certainly glue stuff on to their hearts content.

That being said I just ordered a sample of a prettier cast basket for a prototype. If the steel basket is a deal-breaker for any of you out in lurking land, let me know. It is one aspect of the design that is fairly easy to change (which isn't to say that I will, but I'd still like any feedback).

As usual, I meant to just make a brief comment and typed a chapter. Thanks for the kind words re: Betsy. Hopefully the USPS will deliver 'Zilla's pair today! They better bring my new trumpet mouthpiece and my wife's reeds . . .

Paul
Wild Burro Audio Labs - DIY Full Range Speakers

serenechaos · 29th October 2009, 05:44 PM

Quote:

Originally Posted by pjanda1

I swapped the Cat5 speaker cable I had in the system for the OB's to my reference wire (Jon Risch's cross connected Belden 89259 coax recipe) and I couldn't believe the difference.

Paul
Wild Burro Audio Labs - DIY Full Range Speakers

Exactly my experience swapping out Cat5 for cheap white extension cord speaker cable. I just replaced one side; was going to sit back and to see if I could hear the difference from one side to the other.
My wife was in the next room and ask what the change was; "did you change tubes, or an amp or what?" So much for Cat5s in that context...

badman · 29th October 2009, 05:51 PM

Quote:

Originally Posted by pjanda1

I choose a steel basket for many reasons. I want to maximize price/performance, but also make a driver that didn't look like it prioritized eye candy over engineering. The Visaton will be really well built, but not all drivers are as carefully assembled as the Betsy! I honestly can't hear a difference with the basket. Those that are worried about it can certainly glue stuff on to their hearts content.

That being said I just ordered a sample of a prettier cast basket for a prototype. If the steel basket is a deal-breaker for any of you out in lurking land, let me know. It is one aspect of the design that is fairly easy to change (which isn't to say that I will, but I'd still like any feedback).

As usual, I meant to just make a brief comment and typed a chapter. Thanks for the kind words re: Betsy. Hopefully the USPS will deliver 'Zilla's pair today! They better bring my new trumpet mouthpiece and my wife's reeds . . .

Paul
Wild Burro Audio Labs - DIY Full Range Speakers

More than the basket I'd love to see these with some work on the motor. A little bit of pole extension and some shorting paths go a long way. I'd like to see an extended, undercut pole with a single shorting ring around the base, like image 5b with a ring below the undercut. Motor Types

Then you'd have me a-hoppin' to snag some betsys.

Of note, I did a little modeling- both betsy and betsy k work well in a large sealed cab (assuming one knows they won't get sub-bass) and a big (4ft+) vented cab with betsy k strikes a very nice balance between extension and sensitivity, though output is necessarily limited.

serenechaos · 29th October 2009, 06:03 PM

Quote:

Originally Posted by badman

More than the basket I'd love to see these with some work on the motor. A little bit of pole extension and some shorting paths go a long way. I'd like to see an extended, undercut pole with a single shorting ring around the base, like image 5b with a ring below the undercut. Motor Types

Or even far more work done than shown on that web page!
And adjustable Q!
And affordable!
seemingly impossible, but not too much to ask?
this is exciting...

Andrewbee · 29th October 2009, 08:31 PM

and while you're at it a field coil to play with, much easier to adjust.

rjbond3rd · 29th October 2009, 09:43 PM

Good news to report. Betsy now goes down to 40Hz (initially, 50Hz was the lowest I could hear before break-in.) It's low but audible. I wish I had a (cheap) measurement kit.

Serenechaos, I would love it if you brought an Azurahorn (and your evil grin

I've never seen one in person. That would be a great thing to hear Betsy through.

Pjanda1, thank you for the good advice! So you play trumpet /and/ trombone?

Godzilla · 29th October 2009, 09:55 PM

>>> Hopefully the USPS will deliver 'Zilla's pair today!

I got them and have been listening all day. They sound very good in sealed boxes. Compared to Pioneer B20... well, there really is no comparison. I am going to try to get my OBs all cut up this weekend and hear them on what they were designed for.

Godzilla

pjanda1 · 29th October 2009, 11:26 PM

Badman, I'm not excited about doing a shorting ring. I know it would lower distortion, but it would also give about 5db of treble rise with most amps. I've tried it, and without a compensation circuit, it makes my ears bleed. Some folks love that sound. Others will happily use a circuit. From what I've heard, most of my customers want a driver that they can implement without filters and get reasonably flat response in room (which I find it was happens with the current on axis rise).

If you guys want something in particular, let me know. If five or so of you want a shorting ring on the current motor design, we could talk.

I know I need to get the site updated. I should at least include some enclosure designs for the BetsyK, as the selection has grown considerably. I think the BetsyK really shines in cabinets that have a little more gain and excursion control than a standard vented box. I really like the little TL (12x13x44") in just tossed together. I need to assemble the second pair with a bit different folding, as they didn't end up tuned as low as I had hoped.

RJBond: Everybody and every room is different, so that is why I'm hesitant to answer "extends down to XXhz." The Radio Shack SPL meter (less response at the low end, see google for correction tables) and internet test tones may not be professional, but can certainly provide entertainment and enlightenment.

'Zilla: I'm jealous. This big snow (now over a foot on the ground with wind) seems to be keeping the USPS away from my door.

I spent a couple of degrees and a few years following trying to be an orchestral trombonist. It certainly lost its luster. Now I have dreams of being a weekend warrior lead trumpet player. I haven't seen anybody double trumpet and trombone. I know some commercial guys pull it off, but at this point, I'm just trying to form some trumpet chops.

I hope I'm not hijacking the thread! I'm as curious as anyone to hear how the B200 fairs. gotta make some custard,

Paul
Wild Burro Audio Labs - DIY Full Range Speakers

mp9 · 30th October 2009, 01:26 AM

I could go for a Alnico version. The cast basket would be nice if it could be shaped with ovalish Xsections for strength and to abate back wave interference. If a shorting ring = rising fq + correction network, really Wⓓon't mind if you sit this one out.
I'm seriously liking that they can perform O.B. without additional amplification + bass driver.
If you do alnico count me in as one of the five.

29th October 2009, 08:31 PM	#16
Andrewbee diyAudio Member Join Date: Apr 2002 Location: Cayman Islands	and while you're at it a field coil to play with, much easier to adjust. __________________ None of us are leaving this world alive. Enjoy it responsibly as you may.

29th October 2009, 09:55 PM	#18
Godzilla diyAudio Member Join Date: Nov 2005 Location: New York	>>> Hopefully the USPS will deliver 'Zilla's pair today! I got them and have been listening all day. They sound very good in sealed boxes. Compared to Pioneer B20... well, there really is no comparison. I am going to try to get my OBs all cut up this weekend and hear them on what they were designed for. Godzilla __________________ www.zillaaudio.com/bib/bib.asp www.ZillaAudio.com

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28th October 2009, 02:32 PM	#11
serenechaos diyAudio Member Join Date: Feb 2004 Location: los alamos	No, you probably don't want to know what Tull is about... I've loved that album since high school though. Can I bring a 160Hz azurahorn by, to set in front of a Betsy so you can really hear it? (evil grin)

29th October 2009, 05:04 PM	#12
pjanda1 diyAudio Member Join Date: Jan 2005 Location: The Nebraska Panhandle	There isn't much I can add here, as I'm glad that you're enjoying them! RJBond and I talked a bit via email about messing with the Qts via wire and resistors. I am testing some prototype TL's (for the BetsyK). Initially I was amazed at how much bass they were producing, but it seemed over the top. I swapped the Cat5 speaker cable I had in the system for the OB's to my reference wire (Jon Risch's cross connected Belden 89259 coax recipe) and I couldn't believe the difference. This is what I expected to hear. Most wire is cheap, and certainly worth playing with. I often feel that the OB's are a little "plump" sounding. I need to try the bigger wires. You noticed that the Betsy's smoothed out pretty quickly, which is partially the driver, but greatly due to the application. As OB's don't restrict excursion at all, the driver sees much more action than it would in a boxier application. I try to break all my drivers in in free air or on OB's. The little TLs I just erected for the BetsyK's, for example, keep excursion well controlled, so the drivers spent a day and a half getting pounded on my test bench. I have used rope caulk, but on a recommendation from someone here, I find that less rigid driver mounting sounds better. It doesn't make any sense to me, but I get a better midrange with closed cell foam and mounting bolts backed off a 1/4 turn from snug. Whatever you do, keep it the same for both drivers so the comparison will be fair! I haven't played with it, but folks also seem to experience significant changes with stuff applied to the back of the baffles. I suspect the difference will be lessened when you leave the big wing straight out. The Darkstar guys seemed to like cork. A gent just posted on my blog that he likes "Frostking Duct Insulation". I choose a steel basket for many reasons. I want to maximize price/performance, but also make a driver that didn't look like it prioritized eye candy over engineering. The Visaton will be really well built, but not all drivers are as carefully assembled as the Betsy! I honestly can't hear a difference with the basket. Those that are worried about it can certainly glue stuff on to their hearts content. That being said I just ordered a sample of a prettier cast basket for a prototype. If the steel basket is a deal-breaker for any of you out in lurking land, let me know. It is one aspect of the design that is fairly easy to change (which isn't to say that I will, but I'd still like any feedback). As usual, I meant to just make a brief comment and typed a chapter. Thanks for the kind words re: Betsy. Hopefully the USPS will deliver 'Zilla's pair today! They better bring my new trumpet mouthpiece and my wife's reeds . . . Paul Wild Burro Audio Labs - DIY Full Range Speakers

29th October 2009, 09:43 PM	#17
rjbond3rd diyAudio Member Join Date: Jan 2007	Good news to report. Betsy now goes down to 40Hz (initially, 50Hz was the lowest I could hear before break-in.) It's low but audible. I wish I had a (cheap) measurement kit. Serenechaos, I would love it if you brought an Azurahorn (and your evil grin I've never seen one in person. That would be a great thing to hear Betsy through. Pjanda1, thank you for the good advice! So you play trumpet /and/ trombone?

29th October 2009, 11:26 PM	#19
pjanda1 diyAudio Member Join Date: Jan 2005 Location: The Nebraska Panhandle	Badman, I'm not excited about doing a shorting ring. I know it would lower distortion, but it would also give about 5db of treble rise with most amps. I've tried it, and without a compensation circuit, it makes my ears bleed. Some folks love that sound. Others will happily use a circuit. From what I've heard, most of my customers want a driver that they can implement without filters and get reasonably flat response in room (which I find it was happens with the current on axis rise). If you guys want something in particular, let me know. If five or so of you want a shorting ring on the current motor design, we could talk. I know I need to get the site updated. I should at least include some enclosure designs for the BetsyK, as the selection has grown considerably. I think the BetsyK really shines in cabinets that have a little more gain and excursion control than a standard vented box. I really like the little TL (12x13x44") in just tossed together. I need to assemble the second pair with a bit different folding, as they didn't end up tuned as low as I had hoped. RJBond: Everybody and every room is different, so that is why I'm hesitant to answer "extends down to XXhz." The Radio Shack SPL meter (less response at the low end, see google for correction tables) and internet test tones may not be professional, but can certainly provide entertainment and enlightenment. 'Zilla: I'm jealous. This big snow (now over a foot on the ground with wind) seems to be keeping the USPS away from my door. I spent a couple of degrees and a few years following trying to be an orchestral trombonist. It certainly lost its luster. Now I have dreams of being a weekend warrior lead trumpet player. I haven't seen anybody double trumpet and trombone. I know some commercial guys pull it off, but at this point, I'm just trying to form some trumpet chops. I hope I'm not hijacking the thread! I'm as curious as anyone to hear how the B200 fairs. gotta make some custard, Paul Wild Burro Audio Labs - DIY Full Range Speakers

30th October 2009, 01:26 AM	#20
mp9 diyAudio Member Join Date: Jun 2006	I could go for a Alnico version. The cast basket would be nice if it could be shaped with ovalish Xsections for strength and to abate back wave interference. If a shorting ring = rising fq + correction network, really Wⓓon't mind if you sit this one out. I'm seriously liking that they can perform O.B. without additional amplification + bass driver. If you do alnico count me in as one of the five.

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