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VWR126X Mid Woofer and LD25X Silk Dome Tweeter Preliminary Info

24K views 34 replies 9 participants last post by  mwmkravchenko 
#1 ·
Hi,

The VWR126X started out as a replacement for the FR125S but with a copper coloured cap rather than a phase plug. In spite of their predominance there is good physics to suggest that many phase plugs are more cosmetic than functional. As development progressed it became obvious that frequency response above 10kHz would be a challenge I was not willing to fund at this time. As the LD25X is also ready to go we decided that it would be good to introduce them together and that's the current plan.

The custom cone is a strand oriented flash thermo formed woven composite and the cap is vacuum deposited copper on aluminum. This type of cone is used by a well known British finished loudspeaker vendor and I'm told that one of the "S" driver manufacturers is looking at use it as well.

I'm expecting full measurements and parameters shortly and am planning other drivers using these materials.

Bob

Digital clock Clock Measuring instrument Gauge Technology

 
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#3 ·
We have 4 samples and are expecting the first order to ship at the end of November. Testing it against similarly sized Morel, Eton, Visaton and SEAS drivers we believe it has lower distortion and higher excursion than all of them. We also expect a Klippel report this week from Red Rock Acoustics.

Combining it with the new LD25X one inch XBL silk dome (also expected in the same shipment) with a simple 1st order crossover results in a stand-mount monitor with staggering resolution and clarity.

As soon as they are on a boat there will be preorder special pricing available on both drivers as well as the 2 way kit. There may also be an MTM kit available.

We are very excited about this new direction and plan to develop more high end drivers.

Bob
 
#4 ·
I'm excited to see what this thing can do. I currently own a few of the EL70's and the SDX 7's so i expect this driver to live up to its claims.
A simple two way with only a first order crossover is something to be excited about. It means even novices can have incredibly accurate monitors for critical listening at a price point that won't cause them to burst into tears the first time the cabinet gets bumped.
I feel that what happens with this driver and the tweeter will end up shaping the DIY game for a the next while, by setting the bar incredibly high for others to catch up to, Bob will in turn raise the quality standard of the industry.
 
#6 ·
Hi,

Both the VWR126X and LD25X (Low Distortion silk dome) production samples by air arrived this week. We will be posting data, pictures, etc. shortly and finalizing the introductory special pricing. The sea shipments will arrive in early January.

The following kit designs are in progress:

Simple ported MT in .25 cu ft with VWR126X running full/direct and the LD25X padded and rolled off with a single cap.

In wall MTM including centre.

In wall MTMMM and MMTMM centre.

Ported MTM in 14 litre (.5 cu ft)

Backloaded horn with 4 VWR126X per side and either a horn loaded planar or a ribbon tweeter.

A series of Fonken style designs from Dave Dlugos where we may ask for some naming help. See Dave's post on nomenclature.

Bob
 
#7 ·
Both the VWR126X and LD25X (Low Distortion silk dome) production samples by air arrived this week. We will be posting data, pictures, etc. shortly and finalizing the introductory special pricing. The sea shipments will arrive in early January.
Shortly??!?!?

I want PICS ASAP!!! :innocent:
 
#11 ·
Looks Good. But whats the diff between these and ert26?
To my knowledge, The ert is a simply tweeter designed for a high crossover point to a wideband mid - to push the crossover out of the immediately audible range.

The LD25X is a modern day long throw tweeter than should handle a lower crossover point in the teens; allowing for a smooth driver transition at the crossover point.
 
#13 ·
You fine gents have pointed out some of the design reasoning behind the tweeter.

What can be one of the greatest reasons is the same thing we all think about when we look for subwoofers.

Volume displacement equals greater sound pressure level.

So why is that of interest in a tweeter?

Well in a proper design it should allow lower levels of distortion. That is definitely the case with the LD25X. Greater volume displacement means that the maximum spl generated off of the tweeter will give you greater headroom. A big plus when you are trying to develop a high end speaker system.

A not to often quoted specification in tweeters is maximum SPL and distortion figures. Soon to be released!

Mark
 
#14 ·
Beyond pure performance information, it is necessary to design a tweeter that will last. Remember that the vc leads need to flex, though just a small amount, at least 100 times as much as the woofer, even more than that compared to a subwoofer. Every time the vc lead flexes, that is just a little more toward its fatigue failure. It would seem that the longer throw tweeters would flex even more shortening the life of those tiny and frail leads.

Or not. (Just echoing the concerns of a couple of others.)
 
#17 ·
Any news?

Lots.

They have been tested to the point of astonishment on my part. I can say unequivocally that these two drivers are in the top two or three of their type in the world. They have some of the lowest distortion widest and smoothest frequency responses I have ever measured.

So what you waiting for?

Last level of verification. This is being done very carefully. All will be revealed when the big guy is ready!
 
#22 ·
Yeah! What Bob said.

Everything is almost ready. Just hold on.

And take a look at the thread that Bob referenced on his website. That will be one of the forst places these drivers will actually be heard by the public.
 
#25 ·
I find it kind of interesting how the DIY community seems to have a clear belief that, invariably, "Metal rings" and Silk doesn't introduce any of its own signature. .. and yet... many notable manufacturers seem to use only metal in their speakers.... KEF, Harman, Focal, Genelec, German Maestro, .... Anyways never mind. I don't mean to take this thread off its course. Your sig, however, probably applies to that topic.
 
#26 ·
So after listening to both side by side you prefer metal domes? Then you have a preference. No material is perfect. Even diamond and, beryllium domes have their flaws. Terminating them correctly to a surround can be the biggest problem.

In my experience which is long and wide spread I have heard the odd metal dome that sounds good. I have heard a boat load that catch your ear to begin with. But over an extended listening they tend to be harsh. Metal domes are better at getting extended top end. But they to so many times with cone breakup creating the highest top end.

Coming back on topic, the LD25X really does perform well. It has a very rare level of excursion and exceptionally low distortion. Two things that are mutually required to get loud and clean. A tweeter that will not readily run out of steam. Do a bit of digging on SPL generated by tweeters and the spectral content of music. You will be surprised at how few can actually keep up. This little tweeter is one of the few that can keep up with room to spare.
 
#29 ·
Biamped.

The reason why is that this is a really high efficiency setup. That was the aim in the first place. We clock in at and around 96 db/watt. Pretty much plus or minus 1.5 db from 30 to 20 000 hertz.

The high efficiency gives you output that just has to be experienced to be believed.
 
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