John Krutke's latest blog- Lots to talk about

[Jed]

Looks like he is testing a lot of drivers lately, getting ready for no free time in the coming months/years.

Anyway, the Scan Speak tweeters look great and so does that new SB Acoustics 6" driver. I hear that SB acoustics is coming out with a 4" and 8" driver so lets hope that it gets a motor like the 6".

I also noted that John is planning a 2.5way speaker using all Scan Speak drivers- in particular the 6600 and 7". Interesting choice going 2.5way and it gets me wondering when we will see a 3-way design from Zaph Audio. Just thinking if maybe his design philosophy involves using a 2 way with an active subwoofer to get the most sound etc.

[jkrutke]

Hi Jed,

Yup, I'm not real big on 3-ways. I've done quite a few but the only one I ever published was the ZDT3. (3.5 way - published on the main page) I do indeed favor 2 or 2.5 way most of the time. Maybe I'm just into elegant simplicity.

Some guys at PE contacted me about making the ZDT3 a project showcase thing for the next flyer, but it didn't really work well since half the parts come from Madisound. So I've offered up a different one I've had in the works for a long time using 6 drivers per side from PE. I'm not spilling any beans at this point since it will be a few months before it's finished.

I do like the new SB woofer, but the surprise for me was the Jordan. Most full rangers have a terrible response curve with massive edge resonance nulls, usually between 500 and 1kHz. I knew right away when I heard the impulse that the Jordan was clean and smooth. I ended up plopping a chair in front of my test baffle and cueing up some music for a half hour.

I wish there was smoother performance from the SB tweeter. Maybe I should send them to DLR for a lambs wool treatment to get rid if that cliff at 3.5 kHz. Typical box diffraction makes it even worse.

[---k---]

That's great that they are putting one of your projects in the flyer. I've been very disappointed with the last several designs they published. Not bashing the designs, they are fine for what they are, but its been a while since they've published a design that approaches Zaph's quality or anything built around here.

[augerpro]

John did you test the RS100?

[Jed]

I agree with Ryan.

If they really want to showcase designs, publish something buildable. Not just that spheroid stuff. While it might be cool to look at, I doubt anyone else will build it.

I'm just trying to decide what I'm going to do with all these empty speaker cabinets and drivers laying around. And with all the new drivers coming out I don't see an end to this madness anytime soon.

Jed

[Brian Bunge]

John did you test the RS100?

Yeah, I want to hear more about the RS100! I'm really interested in how they compare to some of the small drivers and of course, how they look.

I know John isn't planning on adding it to the driver mishmash's until he know's it's going to be a production unit, but I'm hoping he'll at least post a few pics and graphs in his blog.

[dlneubec]

Me too. I hope we see the RS100 tests and some pics before he retires from testing for awhile.

[Dave Bullet]

John might actually find speaker testing helps settle a new baby. After all MLS white or pink noise = vacuum cleaner noise and the latter helped settle our kids

[Rolex]

I'm really excited about the possibility of a 2.5 way with the 8531 and the 6600.

This may very well be the design I've been looking for for a long time now.

[Dave Bullet]

John,

From your blog...
"A "required to finish" project is the plywood laminate CNC cut system with the teardrop shape based on B&W Nautilus design principles. That will be a system that represents the best of everything from drivers to enclosure construction to crossover design"

Have you had a chance to progress this design? Can you drop any more hints on drivers and configuration?

Thanks,
David.

[jkrutke]

That's great that they are putting one of your projects in the flyer.

It's not a done deal yet, we only emailed about it a bit. Don't hold your breath, who knows if/when something from me will ever show up in the showcase. I would like to though, just to give PE something back for their contribution to this hobby.

John did you test the RS100?

It's in hand and I need to finish testing. I owe the PE guys the results before I chat about it with anyone though. Here's a preview. It looks like the rest of the RS series except it's a teeny 3.5" across.

I'm really excited about the possibility of a 2.5 way with the 8531 and the 6600.

So am I actually. Through an arrangement, it will be available from Madisound. The crossover may not be posted however. I will likely only hand it over to Madisound to give out with the drivers. This helps insure that people only build the design with the current version of the 6600. (There are now 3 versions) It's a way for me to post a project using using what are, IMHO, the best drivers that have unfortunately had consistency issues. Some of my best designs get held back for this reason.

John,

From your blog...
"A "required to finish" project is the plywood laminate CNC cut system with the teardrop shape based on B&W Nautilus design principles. That will be a system that represents the best of everything from drivers to enclosure construction to crossover design"

Have you had a chance to progress this design? Can you drop any more hints on drivers and configuration?

I'm still undecided, but all I can say for sure is it will be something that works in 1 cubic foot. The baffle is removable to I can change drivers at will. So far, it's either one 8531 or two Seas W15CY001's. I'm going to hold off posting preliminary pictures, since this is a very long term project and I don't want to stir people up with something that looks and sounds better than a Magico Mini but only cost 1/10th to build. (cue the "buahahaha")

Ok folks, I'm gone for a little while, discuss amongst yourselves. :B

[Jed]

Hi Jed,

Maybe I'm just into elegant simplicity.

Careful John, people might think you're going to build a fullrange Jordan speaker to fulfill this mantra. :W Alright, just slap a ribbon on the top crossed at 10k to fill in the top end. :lol:

[Kevin Haskins]

So am I actually. Through an arrangement, it will be available from Madisound. The crossover may not be posted however. I will likely only hand it over to Madisound to give out with the drivers. This helps insure that people only build the design with the current version of the 6600. (There are now 3 versions) It's a way for me to post a project using using what are, IMHO, the best drivers that have unfortunately had consistency issues. Some of my best designs get held back for this reason.
:B

Two of the best reasons for having my own driver designed where so that I could control consistency and so that I could control supply. The market is such that I'm not sure what Harmon or anyone else is going to do in the next couple years. Even some of the best suppliers have unit-unit changes that can throw a big monkey wrench into a design.

This is one area I think Seas has figured out. They don't change parts randomly like some of the other vendors tend to do without thinking about how it effects everyone downstream.

[peter_m]

John K,
was bracing my self for an extended period of inactivity form you but here you are with so many projects in the works... I tip my hat to you sir!

This might be slightly off topic, but since 2.5 way is being discussed... Between SR-71 & Waveguide TMM, which do you enjoy listening to the most? I there hopes for an updated TMM with a newer woofer like the ER18 or Usher 8945?

Congrats for the baby,
Peter

[tktran]

Hi John,

As usual your updates are a great fun to read, and I was pleased with the performance of the JX92S. It's refreshing to see a 5" metal cone without the signs of the usual breakup modes.

On the downside, it doesn't seem to be suited to the usual 0.25-0.38cu ft vented standmount cabinets that other 5" drivers work nicely in. I've seen many designs of the JX92S in a TL cabinet, but building a full length TL cabinet is much more work.

I there hopes for an updated TMM with a newer woofer like the ER18 or Usher 8945?

I think that's what the 8531G/6600 will be, possibly in the Madisound floorstanding cabinet.

(fingers crossed)

regards,

Thanh.

[capslock]

Two of the best reasons for having my own driver designed where so that I could control consistency and so that I could control supply. The market is such that I'm not sure what Harmon or anyone else is going to do in the next couple years. Even some of the best suppliers have unit-unit changes that can throw a big monkey wrench into a design.

This is one area I think Seas has figured out. They don't change parts randomly like some of the other vendors tend to do without thinking about how it effects everyone downstream.

Not so sure about this. They changed the cone profile on the 7 inch aluminum driver and only gave it a new number (H1142 to H1242), but not a new name, and probably didn't inform the distrubutors properly. Madisound and Intertechnik had the wrong data sheet up for at least a year after the change (which was substantial in terms of frequency response).

Also, there were a few issues with the position of the peak and shelf in W15 and W18 drivers.

[---k---]

John K,
was bracing my self for an extended period of inactivity form you but here you are with so many projects in the works... I tip my hat to you sir!

I think John is going to find himself getting up at 2:00am in the morning to feed or change the baby, and then not being able to get back to sleep. He is going to find himself with sooooo much time on his hands, he won't know what to do with himself. :P

[dlr]

I've had my eye on testing those

Hi Jed,
I wish there was smoother performance from the SB tweeter. Maybe I should send them to DLR for a lambs wool treatment to get rid if that cliff at 3.5 kHz. Typical box diffraction makes it even worse.

Hi, John. More than happy to oblige.

dlr

[Kevin Haskins]

Not so sure about this. They changed the cone profile on the 7 inch aluminum driver and only gave it a new number (H1142 to H1242), but not a new name, and probably didn't inform the distrubutors properly. Madisound and Intertechnik had the wrong data sheet up for at least a year after the change (which was substantial in terms of frequency response).

Also, there were a few issues with the position of the peak and shelf in W15 and W18 drivers.

Well.... there you go. :W

Even Seas has part changes. I have a limited range of experience but I think Seas probably is better than most of the other suppliers.

I don't use them though so go figure.....

[peter_m]

Just noticed the SB Acoustics SB17NRX35 test results.... can it be the perfect match for the Aura NT1-204-8D ???

Could it be a poor man's SR-71 ???

[Jim Holtz]

Just noticed the SB Acoustics SB17NRX35 test results.... can it be the perfect match for the Aura NT1-204-8D ???

Could it be a poor man's SR-71 ???

Is this a paper or poly cone material driver?

Jim

[peter_m]

According to Madisound, it a "coated Papyrus fibre cone". So yes it's a type of paper.

[Jim Holtz]

According to Madisound, it a "coated Papyrus fibre cone". So yes it's a type of paper.

Thanks Peter. I should have simply looked myself. I checked John's tests and it does indeed look very, very nice. Exceptionally so for a paper cone driver. I wish the price was about $20 less. It falls in the same price category as my favorite TB W4-1337SA.

I'm looking forward to seeing and hearing some designs with the SB drivers.

Jim

[mbutzkies]

Zaph thanks for the tests, we all appreciate it.

I too thought the jx92 was very interesting. Did you do any off axis testing of that driver? I think we would all be interested how it beams? I wonder how effective it uses circumfrencal(sp) nodes to help mitigate beaming like a bending wave driver.

I don't know if you have any relationships with other testers but npdang at diymobileaudio.com has a kippel system and the jx92 is rare enough he might want to test it. I don't know if that's your driver or not, but the more tests the better I say. I assume markK is not actively testing anymore.

The other interesting item has been the variablity of the 6600 tweeter.

[Dennis H]

Yeah, I thought the Jordan was interesting too and thought it might make a nice inwall surround speaker. Then I saw it costs $180. OUCH! Here's a pic of the 0 and 30 degree response from the Jordan USA website.

http://www.jordan-usa.com/

[Jed]

Thanks Peter. I should have simply looked myself. I checked John's tests and it does indeed look very, very nice. Exceptionally so for a paper cone driver. I wish the price was about $20 less. It falls in the same price category as my favorite TB W4-1337SA.

I'm looking forward to seeing and hearing some designs with the SB drivers.

Jim

Looks to have a pretty severe cone/surround mismatch. If JonMarsh was here he'd be commenting on that impedance wiggle and floppy cone suckout like many of the old Scanspeaks. Not sure how much it would be audible though. But even the little 5" has it at 1.5k.

[Jim Holtz]

Looks to have a pretty severe cone/surround mismatch. If JonMarsh was here he'd be commenting on that impedance wiggle and floppy cone suckout like many of the old Scanspeaks. Not sure how much it would be audible though. But even the little 5" has it at 1.5k.

Hi Jed,

Is that correctable in the crossover?

Jim

[Jed]

Hi Jed,

Is that correctable in the crossover?

Jim

The problem with dips like that in the FR is you have to (usually) bring everything else down to the same level to get a flat response. The good news is the dip occurs close to most diffraction peaks. Like the Seas W15LY, which has the same problem. NOTE: the SB 5" appears to be worse than the SB 6".

[JonP]

[QUOTE=Dennis H]Yeah, I thought the Jordan was interesting too and thought it might make a nice inwall surround speaker. Then I saw it costs $180. OUCH! Here's a pic of the 0 and 30 degree response from the Jordan USA website.

http://www.jordan-usa.com/

I have a friend who got in on a huge group buy at another site. They came in at $120-130 ea. Don't know if there's going to be another... the organizer had something over $10,000 of drivers in his basement. :E

His just arrived the other day. It'll be nice to hear some of these in person...

[Mark K]

Zaph thanks for the tests, we all appreciate it.

... I assume markK is not actively testing anymore...

The other interesting item has been the variablity of the 6600 tweeter.

Oh no! I've been marginalized!

Well, it's true I haven't been testing drivers much. My time has been limited and I've been spending it on my active dipole project.

I've actually tested the Jordans, but it's been ~4-5 years ago, so it's hard to know if the drivers are the same. Also, my testing methodology wasn't up snuff, so to speak. Still, as I recall the bass performance wasn't all that good. I mean, it may be good compared with other small drivers, but, well, that isn't really saying that much.

I mean what can you say? The bass is a bit shy, and the high frequency power response isn't my cup of tea. Yes, you get the advantage of no crossover, but the other compromises...

Anyway, I'll look on my old PC and see if I can find the test data on the Jordans. They were actually tested in a very nice finished box from one of our local radiologist turned amateur woodworkers.

PS I am revamping my site and will have some stuff to come. I'm curious about the Seas minihorn tweeters myself and, well, the TB titanium drivers have this kind of sexy siren song that keeps calling me.

[Paul Ebert]

Mark,

Is your active dipole documented somewhere? I'd be quite interested in reading about it.

[Mark K]

Mark,

Is your active dipole documented somewhere? I'd be quite interested in reading about it.

I'm generating a brain dump for the active dipole as part of my new site. It's more so that people can follow along with my design process-not so much that I'm great, blah, blah... I'm just hoping that it will motivate folks to build their own. With the stuff that's out there from SL and John k, it's really not as hard as some think.

Anyway, probably in the next month or two I'll have a completely updated website with a long run-on blogesque page about the RST dipole.

It's not finished by any means yet. I'm just at the point of soldering up the active board for the dipole eq. I still have to remeasure with the dipole eq in place, so I can design the passive crossover for the mid and tweeter.

hope that helps.

mark

[mbutzkies]

MarkK, I apologize, I did not mean to marginalize you.

I appreciate all your hard work too.

I think it's a little unfair to expect the jx92 to have a bass response of a 7" driver. I think the best use is a very wide band midrange. Other midranges like the 13m/8636 or mg10 have even less bass performance than the jx92.

Something must be wrong with htguide, all this positive talk about two floppy cones.

[WillyD]

Jon has posted some RS100 data! I think it looks pretty dang good. I could see many speaker designs utilizing this driver.

[peter_m]

MarkK,
any progress on your 830883 TM design? Has the di-pole taken over?

...falls in the same price category as my favourite TB W4-1337SA...

True but it should have more lower-end with a 6" diameter?

...I think that's what the 8531G/6600 will be, possibly in the Madisound floorstanding cabinet...

Crap, I will sound too good for me, or should I say for my wallet 8O

Peter

[jdybnis]

Seems like the RS100 could do with a bigger magnet. Lower Qes and higher efficiency.

[Rick Craig]

Seems like the RS100 could do with a bigger magnet. Lower Qes and higher efficiency.

There are some reasons why it's designed this way. Lowering the Qes makes it less usable in a sealed box plus the driver size limits the possible magnet size / width. A typical application will be for a nearfield situation such as a computer speaker where sensitivity and output capability are not as demanding. With dual drivers in a MTM with an added subwoofer you could get decent output for a small listening room. They also would be ideal for a line array.

[thadman]

Any predictions on the price of that RS100? It looks tasty :B