Tony Gee's USB and the SEAS T18

[MMeche]

For my second ever DIY project, I have tentatively selected Tony Gee’s USB. To give my family a chance to benefit from my current obsession my next project will be targeted at upgrading our HT speakers, starting with the center channel and maybe the front pair. I have spent a fair bit of time reviewing discussions on the merits of Coaxial or single driver solutions verses MTM and other horizontal arrays in the center position. My wife would probably start to question my judgment if I proposed a vertical format. I also like the idea of idea of ending up with all 5 loudspeakers being identical for the purpose of getting some multi-channel music satisfaction.

So after much cogitation, I began closing in on the USB and even asked Tony to send me the larger scale plans only to find out that I might have some trouble sourcing the driver, the Seas T18RE COAX-TVFC-H1144 . I did manage to find a few discussions on the updated versions as a substitute driver but not with Tony’s USB box design and XO. I would appreciate some input on the following questions:

Is the current driver a suitable direct substitute?

If not then has anyone successfully tweaked the box and XO?

Is there another design with a similar configuration by a capable designer that I should consider?

My loudspeaker design and construction adventure is just beginning so it is important to me to have some successful reference projects prior to mucking with the recipes. Therefore I don’t really want to experiment; I want to build a known and appreciated design.

 

[AntonZ]

Madisound sells a kit with the newer version driver and a XO, the Loki. I do not know how well the XO from this kit is adapted to the specifics of the H1333 driver. As far as I know it can be crossed over significantly lower than the older version, at a frequency where dispersion is very similar between woofer and tweeter, if my information is correct.

I do not have a design and/or crossover available for this driver, if someone has I might give it a try as well.

 

[MMeche]

Anton--thanks for connecting the dots. There are so many drivers out there, my newbie head is spinning (and it seems as though 20 digit model numbers roll off the toungues of some veterans like so much poetry). After some brief research, it seems the Loki has managed to gather a few positive comments so I will give it some consideration. On Tony Gee's recommendation, I intended to buy some premium caps for the USB XO and wonder how the quality of the manufactured PCB XO could be.

As it turns out, Elliot at Zalytron has the very driver I was looking for in stock so I might end up doing some comparisons. Decisions, decisions!!

 

[peter_m]

Coaxials have issues with the tweeter being almost horn loaded. If you prefer a more conventional design, look at this: http://zaphaudio.com/ZBM4.html About as small as you can go to integrate with a 80hz sub.


Peter

 

[MMeche]

I have my eye on the ZBM4 and other mini-monitors but for a different project.

I have read a few discussions on the "horn loaded" but don't yet understand how that is a problem. I am leaning toward the coaxial solution and its point source nature in order to deal with a rather shallow room and the need for a broad listending area.

One thing I like about the USB is that it uses a premium driver but just one of them. I was thinking that it will give me a taste of the next shelf up in quality without a large captial outlay and if it not entirely successful, the USB can be demoted to some other room or the parts can be used in some other project. I expect to spend some seroius $$$ at some point but consider these first project as a way to develop some judgement for the ultimate purchases.

Yesterday I completed my first DIY loudspeakers, a pair of North Creek Echo and am quite impressed with what is really a modest kit. I selected this kit more as a proof of concept that DIY loudspeakers are worth doing. The Echos have been running for less than hour and are just sitting on top of my bench breaking in but my first impression leads me to wonder what I am going to do with all the B&W speakers lying around.

The Echo project is an amazing value and certainly proved to me that speaker building not only provides satisfaction but can result in great speakers however, given the amount of time it takes to build them properly, trying to save a few hundred dollars in parts is not worth it.

I will give George Short at North Creek a plug. Aside from his design work, his handbooks and instructions provide good support and teach you at least one good way of putting together speakers. Most of the plans I have reviewed lately are thin on that sort of detail but with North Creek project already under my belt, I have some experience to build on.

 

[MJL21193]

For my second ever DIY project, I have tentatively selected Tony Gee’s USB.
So after much cogitation, I began closing in on the USB and even asked Tony to send me the larger scale plans only to find out that I might have some trouble sourcing the driver, the Seas T18RE COAX-TVFC-H1144 . I did manage to find a few discussions on the updated versions as a substitute driver but not with Tony’s USB box design and XO.

Hi,
Solen still sells the H1144. I bought one about a month ago for my centre speaker and used Tony's design and crossover to build it. There are some differences, but largely the same.

Starting here in my thread, I detail how it worked for me.

This is a great design, much better than I thought it would be.
You won't be disappointed.

 

[MMeche]

John;

Thats quite an adventure you have going and some beutiful work. You are way ahead of me. I am encouraged that I seem to be making good decisions. I have a few aesthetic tweak planned for the cabinet as well, maybe enven a radiused baffle like yours.

I have a couple of questions: you spoke briefly of foam wedges, what is that about? The only speakers I have built so far (North Creek Echo kits) use a mix of drywall compound and liquid nails to help dampen things. What do you use?

Is the vertial format on a paint bucket an acoustic or compositional preference?


regards;

Mark

 

[MJL21193]

Thanks Mark,

IMO, you've picked the right design. These would make very capable mains too.

The wedges were a method of back wave treatment that I tried in the main speakers. It was not successful, so I didn't do it in the centre. Details on the wedges are further back in the thread.

For back wave damping, I'm now using rockwool. I've tried BAF, pink fiberglass, carpet, nothing works like rockwool.

For panel damping I use my own version of CLD - the panels are two layers, separated by a layer of silicone rubber caulking. The idea is the inner panel vibrates and dissipated it's energy through friction, flexing against the outer panel. This seems to work VERY well, no disappointments there. Even at high volume, there's not much vibration coming through to the outside.

My centre will be stand mounted in that vertical orientation. I think it looks better. Dispersion is excellent from this driver.

 

[MMeche]

Inductors

John

Where can I get the appropriate inductors for the XO, or does a precise match matter. Most of the inductors I find are fabricated in AWG sizes and the DCR is a bit off. Is this important? I did find a place with the 2.00 mm inductors that match precisely but the price is a bit wild and more importantly, the shipping cost more than the part.

I am willing to pay handsomely but only if it is important. Tony did make a comment that spending money on good caps is recommended but did not say too much about the inductors. What do you think?

 

[MJL21193]

Hi,
When I ordered the driver, I ordered the crossover parts at the same time from Solen.
For the 1mH I used a 16 gauge that was $12 and for the .47mH I ordered an 18 gauge, but they sent me a .27mH coil instead. I had to raid my parts bin to find one closer (found a .51mH and unwound a few turns).

IMO, it's not critical to be ultra low with the DCR, just within reason. The DCR of the 1mH coil I bought is .3 ohms - low enough.

As for caps, I use the mid priced ones. I'm not a big believer in the overpriced ones.
Tony probably has better hearing than me though.