[Saurav]

Jon Ver Halen, the Lowther representative for the US,  recently built a pair of OBeez using the TT 12 as a lower register driver, along with a PM6A

I heard these at VSAC. This was my favorite 'normal-sized-speakers' room at the show (i.e. not counting the large horn systems).

The baffle is really well made, it's thicker in the middle than at the edges, and the curvature 'squares out' near the bottom where the TT driver is mounted. Far beyond my construction skills. Jon described most of it in his post, the only other piece of information I can add is that it has a 1st order series XO @ 200Hz between the drivers (I asked him what he'd done). As far as I could tell, no dipole EQ or other shaping of any kind. You should look up the pictures of the amp that was driving these

It's pricey though... I think each of those Lowther drivers is $800, and the TT's are, what, 2-300? He had a sign up saying he'd sell the system for 3200 or something like that, and I think it mentioned it had ~2k in parts cost.

[MJK]

Jon Ver Halen, the Lowther representative for the US,  recently built a pair of OBeez using the TT 12 as a lower register driver, along with a PM6A

I heard these at VSAC. This was my favorite 'normal-sized-speakers' room at the show (i.e. not counting the large horn systems).

The baffle is really well made, it's thicker in the middle than at the edges, and the curvature 'squares out' near the bottom where the TT driver is mounted. Far beyond my construction skills. Jon described most of it in his post, the only other piece of information I can add is that it has a 1st order series XO @ 200Hz between the drivers (I asked him what he'd done). As far as I could tell, no dipole EQ or other shaping of any kind. You should look up the pictures of the amp that was driving these

It's pricey though... I think each of those Lowther drivers is $800, and the TT's are, what, 2-300? He had a sign up saying he'd sell the system for 3200 or something like that, and I think it mentioned it had ~2k in parts cost.

Saurav,

The sound of Jon's system was probably set mostly by the Lowther driver. He used the bass driver to fill in the lower region but the Lowther was really responsible for the quality of the performance.

In my opinion he did the right thing with his bass driver and baffle size. They complimented each other and he did not try to force the system to play down to 20 Hz. If the baffle width is less than 20" you are not going to get bass to 20 Hz without really brute forcing some EQ to the amp and driver. Having a driver with a lower Qts in the range of 0.7 and a natural frequency of 20 Hz is just not going to produce low bass on a 20" wide baffle without a lot of power and EQ. Why use a big amp and EQ to get a driver with a Qts < 0.7 to play like a driver with a Qts of 1? Just buy the higher Qts driver and save on driver cost, amp cost, and EQ cost. Pushing a lot of power into a driver cannot be a good thing when another option is available.

Having a driver that has a Qts closer to 1 and a natural frequency between 40 and 50 Hz is going to naturally fit into the ~20" wide baffle and produce decent bass down to about 40 Hz without any need for excessive power or EQ. This combination works well together, I think you heard the evidence in Jon's system.

In my opinion, and this should not be a huge surprise considering my design approach, spending a lot of money on the woofer is a waste. As long as the woofer is well made/designed, has an fs of about 40 Hz, and a Qts of about 1 you have all that you need for a moderately sized OB bass system. You are only going to need the driver to go as high as 200 - 400 Hz and this should not be a huge challenge for this type of driver. I really don't believe Xmax, distortion, or break-up modes above 1 kHz are that important for music reproduction. For HT, I am not sure an OB is the best choice for explosions.

Use the higher Qts driver and figure out how to match the efficiency of the midrange or full range driver and move on. Simple and cost effective. If you have to get down to 20 Hz use a sub specifically designed to fill in the 20 - 100 Hz region. People are so focused on lower Qts driver based on their years of experience with boxed speakers, you need to think completely differently for an OB bass system.

Martin

[Saurav]

Thanks for the advice. I'll have an active XO between the woofer and the midrange, so I can handle a mismatch in efficiencies. I'll probably also need a higher XO than most people (I'm shooting for 4-500Hz) because of the midrange driver I'm thinking of using. And I'll be using a monopole sub to fill in from wherever the OB starts to roll off, I'm not planning on excessive EQ to try and squeeze bass out of the OB woofer. So... that's what I'm looking for.

And thank you for your worksheets, they have been very helpful in modeling various woofers and baffle sizes to get a feel for what I can achieve.

[Dmason]

I agree with Martin's [as usual] impeccable logic; what has me going is that the lower register presentation was accounted for using a 12 inch driver. Personally, I can't stick the whole 15 inch black shape in the livingroom factor. 12 is in my mind much easier to live with.

The Eminence Alpha 12 has published critical parameters almost identical to the TT 12. This is a good and happy thing. You could also shave an inch or two off baffle width with little detriment to that lower register, in my opinion. I think one of the contributing factors to the success of the sound, apart from the "Lowther factor," -which are not my cup of tea, is the use of a smaller diameter wideband driver all the way up, from the XO point. Yes, it would appear once again that this is the way to go for simple OB success. And for hemp tone sweetness, one could try the Tone Tubby 6.5, which is the apple of the eyes of the Tubsters, they are really impressed with it, which is an interesting anecdote, because the whole hi fi line to them is abit out of bounds, as they have been in the R n R groove for years and years...and its SPL rating is similar to an Eminence Alpha 12. For a budget level KILLER OB, I believe this might be a nice way to go. Under 500 for bass/mains drivers, and small plate amp.

For me, these little Fukiun/Coral/Pioneer 4.5 light paper/alnico magnet jobs are sounding better and better and better. As my listening habits change, something like this, at night, in the dark, listening to very well produced orchestral music, I think I might have found what I was looking for.

[Saurav]

I've been hesitant about 15" drivers for the same reasons. But I'm not sure an Eminence Alpha12 will get me the bass output I want, for the kind of music I listen to. Its Qts is quite a bit lower than the Alpha15, IIRC. I don't claim to understand this very well at all, but I think one of the factors that makes the Alpha15 work in MJK's design is its very high Qts.

Where do you find T/S information on the Tone Tubby drivers?

[Dmason]

The info on the Tone Tubby drivers is now even more woefully absent.  I mentioned a couple of times to Jason that those numbers, -as immaterial as they may seem, are essential for the DIY types to make decisions based on the thumbnail sketches those numbers provide. The lack of apparent motivation to publish this information has to do with the fact that Tone Tubby is primarily a guitar oriented gig, and they know that parameters can be made to be just about anything. In their own conclusion. If everyone emailed Jason, this may change faster. Jason is also a rocker. John is scratching his head about the whole explosion of interest in the other stuff; totally amazed and stunned by it. When I feel better I will drive up and visit him, as we live in the same county.

For a virtual library of manufacturer-published specs., www.usspeaker.com 

I like the look of the Eminence Alpha 12, and will be ordering a pair. These will be mounted on a baffle and thrown in the car when I eventually get around to the visit with Jason which has been put off for several months, due to my mononucleosis, which has put off my whole life for several months now.

Bass output can be just about anything you want, within limits, when you use bi amplification, and EQ or active contouring, even the simple one octave EQ in iTunes will work wonders for OB considerations, and room considerations, for box type alignments. The use of a hard drive/DAC/iTunes front end solves those issues, your own bass and SPL desires notwithstanding. Point is, I really like what I see in Jon's set up in terms of size, non 15 incher, and small diameter high quality wideband with simple HP, and I like the use of the motor-Run cap, nice touch, Jon, if you are reading. My guess is the panels were CNC milled out of Maple by Jason Flanery, the present owner of what was, Cain & Cain. The wood, the fit n' finish, and high degree of artistry, and attention to acoustics such as the convex baffle plane, is pure Terry Cain, in spirit, a dear departed friend, and therefore those things are even more attractive to me.

[MJK]

I've been hesitant about 15" drivers for the same reasons. But I'm not sure an Eminence Alpha12 will get me the bass output I want, for the kind of music I listen to. Its Qts is quite a bit lower than the Alpha15, IIRC. I don't claim to understand this very well at all, but I think one of the factors that makes the Alpha15 work in MJK's design is its very high Qts.

Where do you find T/S information on the Tone Tubby drivers?

The 15" driver with the high Qts allows the bass extension and the low displacements at reasonable volume levels. At first the 15" driver looks huge but you get used to it. If you want decent low end in a simple set-up you are going to need a baffle that is at least 15" wide to get there, so to me a wide baffle with a 10" or 12" woofer is still a wide baffle so why not just bight the bullet and go all the way to a 15" woofer. It won't look that big because there is no box behind the baffle. Cover the baffle with a cloth grill and you won't even know the size of the woofer. The clean dynamics you get with a bigger woofer make the whole thing sound better.

The other thing you need to watch out for is the higher crossover frequency you are looking to use. You are going to have a ~5 dB hump in the response centered between 200 and 700 due to the baffle shape, your crossover needs to work with this hump to provide a smooth SPL response. Having the crossover frequency lower for the woofer and higher for the midrange you can use the hump to bring the acoustic crossover to some place in the middle. This is dead easy to dial in with an active crossover.

[Saurav]

You are going to have a ~5 dB hump in the response centered between 200 and 700 due to the baffle shape

Yep, I see that in your models as well as EDGE. I'm not too worried about that - I'll be using some modular PCBs to build my active XO, so a combination of underlapping the highpass/lowpass frequencies and/or a gentle notch filter should take care of that. If everything lines up, I hope to use the dipole rolloff on the mids as part of the XO slope as well, and reduce the electronics slope (I'll probably have a ~12" baffle up around the mids, which puts the dipole peak higher, and maybe put wings around the woofer to increase D for that driver).

I've run some simulations for all this, but I'll have to wait until I measure the drivers on the baffle before I'll know exactly what I'm dealing with, so I'll cross this bridge when I get to it. But I think I have a rough idea of what will be needed.

[nullspace]

Where do you find T/S information on the Tone Tubby drivers?

There are links to the archived ToneTubby webpages (both 12" and 10" 8ohm versions) back on the first page of this thread.

Regards,
John

[FlorianO]

And also could you give some page info for the 'Beyond Ariel'-thread to get to the relevant passage ?

/Erling

Beyond the Ariel post #3847 -- OB with Lowther PM6A + ToneTubby 12''

Please note Lynn's comment down the thread. I also think that you can interpret his "complementary sonic characteristics" remark  in two ways

F.

[Michael V]

For me, these little Fukiun/Coral/Pioneer 4.5 light paper/alnico magnet jobs are sounding better and better and better. As my listening habits change, something like this, at night, in the dark, listening to very well produced orchestral music, I think I might have found what I was looking for.

Do you have any info on these Pioneer fullrangers?

Thanks

[Dmason]

None. They are NOS 40+ years old, likely radio and TV replacement jobs. These types of drivers have caught on in Japan and when fed a modern high quality signal thru a quality amp such as SET/T they sound pretty sweet. These were OEM either made by Fukiun or Foster of Tokyo. Foster (Fostex) eventually bought out Fukiun (Coral) and many of the Coral designs continue to this day as Fostex, especially the FE103E, and the series of ALnico supertweeter horns, as well as the high dog 12 & 15 inch woofers. These were originally back-engineered, better mousetrap JBL 2226. They are Unobtainium, in Japan, horded by those who also own Western Electric amplifiers and things like that.

Again, light paper cone, small diameter, relatively large Alnico magnet wideband driver, made to a very high standard, hard to beat. At first they sounded tinny and horrid but that is because they have been asleep for 40% of a century, and have relatively stiff spiders, but over time, and I suspect a fairly long interval, they should break in to reveal a wonderful tone, typical of any high quality light paper cone with Alnico motor.

[scorpion]

FlorianO,

Thanks Florian, no I do not think there was any second meaning. But Tone Tubbys was not used in any great frequency register. In fact I think it was almost a waste of its possible virtues in that use. How much of a speaker do you hear from 50 - 200 Hz ?

I look forward to read painkillers report !

/Erling

[nullspace]

Thanks Florian, no I do not think there was any second meaning. But Tone Tubbys was not used in any great frequency register. In fact I think it was almost a waste of its possible virtues in that use. How much of a speaker do you hear from 50 - 200 Hz ?

/Erling

Hi Erling --

I was wondering the same thing, so I messed around with MJK's worksheets this evening. If the particulars are at all close to what I was using in MathCAD, the 1st-order series electrical results in an effective crossover around 300hz and the TT 12" contributing significantly up to 600-700hz. To me, that seems like it could be a pretty good use for a nice driver like that.

Regards,
John

[FlorianO]

Erling,

FlorianO,
Thanks Florian, no I do not think there was any second meaning. But Tone Tubbys was not used in any great frequency register. In fact I think it was almost a waste of its possible virtues in that use. How much of a speaker do you hear from 50 - 200 Hz ?

You're welcome .
Well, it's not that range that I was thinking about (under 200Hz the drivers are little more than air pumps, IMO) but-- as John promptly points out in his post (thanks John!) -- the 1st order XO make the TTs contribute significantly all the way to the midrange: -18 dBs down at 800Hz and (still) -24 dBs down at 1.6k, right where the Lowther start to "shout". IOW still putting out quite a bit of output (say you're listening at 85 dB SPL).

I haven't listened to the TTs (too expensive-but-unproven for my blood), but if Lynn's (and others) report is anything to go about the Alnico magnet and the hemp cone gives that driver a mellow, "vintage" tone that should complement the Lowthers.  Well, I would _love_ to hear that OB, but I wouldn't buy that driver combo "blindly" and build that OB w/o listening first, to be honest.

I look forward to read painkillers report !
/Erling

Honestly, so do I ! painkiller, where exactly in Norway are you located ? Maybe me and Erling could come and visit with a full case of "cold ones" ?

All the best,

Florian

[painkiller]

Yes, I'm looking forward to my report myself.  aa

But right now the customs have been sending my drivers back and forth between different warehouses for over a week. Don't know what's taking so long. They're usually pretty effective.

I live close to Oslo. But I'd like to make a suitable baffle, and find a matching tweeter before we can start talking about beer. 

[Dmason]

"mellow," and "vintage," are hardly words I would use to describe the sound of thoroughly modern drivers using hemp cones and Alnico magnets... if anything I would say they elicit a "sophisticated" sound, which is catching on fast. At least to those whom have had a listen.

 I find it interesting that a rather loud opinion on the matter is offered by someone with -Zero- experience in or on the matter.

"ignorance hath the loudest opinion" -Rudyard Kipling

Hopefully the clerically minded, civilly servile will get your speakers to you, no doubt you will be impressed, one way or another.

[painkiller]

Finally! I got my drivers yesterday evening. They were thoroughly packed for shipping, and there were no damage to the drivers. Phew. Thanks to South Valley Vintage Amps. They seem very professional and offer great customer support.

I placed the drivers on the floor and hooked them up, and they work fine. The spiders and cones feel very stiff, but there is quite a bit of movement on bass notes, so I guess they can give some kind of bass extension with a suitable baffle. Beaming is apparent. Initial impression is that a tweeter is mandatory with these drivers. At least for us who still hear at dog frequencies.

So this weekend I guess I'll be making a couple of 800x900mm baffles and do some measurements.  I'm really eager to see what these drivers can do.

[painkiller]

Some pics:
http://www.audiocircle.com/index.php?action=gallery;area=browse;album=1481

[Dmason]

Congrats, Painkiller, on your new California hotrods.!! Twin ambassadors of candyapple madness in your home.

If you can at all burn them in abit before measurements, or remember that the first 100 or so hours with these hemp cones, the performance fluctuates wildly, from the merely okay, to the downright unlistenable, in my experience.

Initial measurements will indeed vary from measurements taken down the road abit. Whatever your initial impressions will be, ie, likely less than neutral, is not indicative of what these drivers ultimately will sound like, and therefore presumable their critical parameters are changing as well. The sound simply changes over time, and takes on a kind of dimensional depth I have not heard from any other cone material.