Zaph XT19 in MCM waveguide

[Pete Schumacher ®]

I was looking at John's blog and saw his data on the Vifa XT19 in the MCM waveguide.

If anyone is intent on using that combo, I thought I'd post a crossover that produces something very close to LR2 at 2KHz, with 4 components. With the built in acoustic offset of the waveguide, LR2 on a flat baffle with a 7" woofer looks eminently do-able. And the resulting tweeter distortion will be relegated to nearly non existent.

[critofur]

I just recently got my first pair of XT19 tweeters the other week.

I just love it when I see "10uF" - I think I will have to pickup a 100 count bag of those fine "surplus" 10uF caps at 50 cents ea.

What baffle dimensions/tweeter position did you use for your sim? (I'm assuming the waveguide is not quite eliminating the effects of baffle step & diffraction?

The PE waveguides are slightly more affordable, I should do a test to see how they compare to the MCM ones...

Slightly OT: BTW, it's really cool how the little Vifa tweeters without the faceplates fit right in the MCM waveguides without having to machine them [There may need to be some slight modification where the tweeter surround could be touching the inner edge of the throat of the waveguide]

EDIT: Also nice how the output drops so sharply as you go below 1Khz...

[Pete Schumacher ®]

I just recently got my first pair of XT19 tweeters the other week.

I just love it when I see "10uF" - I think I will have to pickup a 100 count bag of those fine "surplus" 10uF caps at 50 cents ea.

What baffle dimensions/tweeter position did you use for your sim? (I'm assuming the waveguide is not quite eliminating the effects of baffle step & diffraction?

The PE waveguides are slightly more affordable, I should do a test to see how they compare to the MCM ones...

Slightly OT: BTW, it's really cool how the little Vifa tweeters without the faceplates fit right in the MCM waveguides without having to machine them [There may need to be some slight modification where the tweeter surround could be touching the inner edge of the throat of the waveguide]

EDIT: Also nice how the output drops so sharply as you go below 1Khz...

The WG actually does remove most baffle effects, effectively becoming the baffle. Width should make no difference

[johngalt47]

What is the model number of the waveguide?

[Pete Schumacher ®]

What is the model number of the waveguide?

The MCM waveguide he references in other sections of the blog is the 6.5" version. He's also used the PE 8 and 10" WGs.

[benchtester]

What is the model number of the waveguide?

I assume it is the MCM 54-580 (6.5" horn lens). It has been very popular with the DIY'ers. You can see it in John's project:

http://www.zaphaudio.com/Waveguidetmm.html

However, searching the MCM site I can not find it!!!

[lunchmoney]

Has anyone tried making waveguides using rapid prototyping methods?

FDM, SLA, Polyjet, etc...

The accuracy and control over the exact shape would be absurd. You could do radiused, elliptical, progressive radius, anything. So easy.

Not cheap, but neither is having them machined.

[benchtester]

Has anyone tried making waveguides using rapid prototyping methods?

FDM, SLA, Polyjet, etc...

The accuracy and control over the exact shape would be absurd. You could do radiused, elliptical, progressive radius, anything. So easy.

Not cheap, but neither is having them machined.

I hadn't really thought about it, but like you say, SLA would be pretty easy. I'll make a wild guess and estimate the cost around $100-$150 from my source. One could then make a fiberglass (or silicone rubber) mold and duplicate it for the modest cost of materials.

The big question is how many iterations would it take to get the right shape?

I took a pragmatic approach (ref: my blog) and back mounted the tweeters with a big hole, which I filled with clay and shaped it while making FR curves. It certainly showed what didn't work. In the next several months, I will have access to a little 3D scanner. Then I will do some curve-fitting on the data to determine what kind of curve it is.

[DanP]

I have direct access to an SLS machine running a really strong glass-filled nylon. As long as I keep the size down, the owner of the company is cool with me making personal stuff for free. Large components really start to cost the company, so I avoid making those. I've been wanting to try some waveguides, but I have no loudspeaker measuring equipment, so once I made them, I'd be flying blind WRT my tweeter response. 6"-ish would fall into the small/no problem category and larger sizes could be taken on a case by case basis (by the way, benchtester took a pretty good guess at price - I'd normally charge about $200 for something the size of a 6" waveguide. SLS is a little more expensive than SLA - and substantially stronger.) If someone can draw it up in CAD and get me the file (preferably .stp , .igs , or .x_t), I can knock out a bunch of iterations in a relatively short time. Then I could ship them out to one of you with the measuring equipment to take some measurements and post results.

I'd love to test the effects of a 104mm diameter wave guide that is about 20-25mm deep. This would fit right on the front of most nice tweeters and align the acoutic centers of the tweeter and woofer.

If anyone with CAD skills and/or measuring equipment want to get this going, let me know.

Dan

[Pete Schumacher ®]

Check out the Nuance TW5-120LR buyout

Zaph has it on his blog. Near the bottom of the page. A waveguide that small has limited low end applications, but that little tweet actually looks pretty decent over the range it covers. Zaph mentions that the faceplate could be fitted for another tweeter.

With 2.7uF cap.

[lunchmoney]

I hadn't really thought about it, but like you say, SLA would be pretty easy. I'll make a wild guess and estimate the cost around $100-$150 from my source. One could then make a fiberglass (or silicone rubber) mold and duplicate it for the modest cost of materials.

The big question is how many iterations would it take to get the right shape?

I took a pragmatic approach (ref: my blog) and back mounted the tweeters with a big hole, which I filled with clay and shaped it while making FR curves. It certainly showed what didn't work. In the next several months, I will have access to a little 3D scanner. Then I will do some curve-fitting on the data to determine what kind of curve it is.

Check out polyjet (aka Objet)

Cheaper by far than SLA or SLS, and more than adequate for this application.

I know numerous vendors who can do it.

[Face]

I don't have the part number handy, but there was a Peerless India waveguide buyout not too long ago. The opening almost fits the XT-19, only a little trimming would be needed at the mouth. The biggest issue would be mounting the driver to the guide.

[DanP]

Check out polyjet (aka Objet)

Cheaper by far than SLA or SLS, and more than adequate for this application.

I know numerous vendors who can do it.

Polyjet would be fine, but I know a vendor who can do SLS for free . Let's get this going. I can make a ton of iterations all with different waveguide profiles. I can make them fast and for free. Unfortunately, the CAD software I have available to me does not lend itself to creating geometry easily, so I won't be able to generate the CAD files myself.

This is a great opportunity to get some good data on the effects of different shaped waveguides and possibly identify a FR signature(s) for a given profile(s) that could be imported into PCD to simulate a tweeter's response in the waveguide. I know people have speculated the signature would be different for different tweeters even with the same waveguide, but perhaps there is a geometry that we could experiment with that would minimize throat reflections or any other factors that prevent identical waveguide influence on differing tweeters.

So here's what we need:

1) Ideas for profiles. Keep in mind with the SLS process, conventional manufacturing restrictions do not apply.

2) Someone to generate the profiles in a legit CAD software that can export .stp or .igs or .x_t files.

3) Someone to manufacture the waveguides. That's me. I'll cover shipping to the measurement site. Whoever does the measuring is welcome to keep the waveguides.

4) Someone to measure a few different common tweeters in the several different waveguide profiles.

C'mon guys. Any takers?

Dan

[kmibb]

This sounds like a sweet idea. Someone jump on this. A waveguide with the correct mounting! It would be really sweet to see the effects that differently shaped waveguides have on response and distortion for dome tweets.

Unfortunately I cannot measure or use modeling software.

[Pete Schumacher ®]

I assume it is the MCM 54-580 (6.5" horn lens). It has been very popular with the DIY'ers. You can see it in John's project:

http://www.zaphaudio.com/Waveguidetmm.html

However, searching the MCM site I can not find it!!!

Yep, looks like it's NLA at the moment.

[Pete Schumacher ®]

Polyjet would be fine, but I know a vendor who can do SLS for free . Let's get this going. I can make a ton of iterations all with different waveguide profiles. I can make them fast and for free. Unfortunately, the CAD software I have available to me does not lend itself to creating geometry easily, so I won't be able to generate the CAD files myself.

This is a great opportunity to get some good data on the effects of different shaped waveguides and possibly identify a FR signature(s) for a given profile(s) that could be imported into PCD to simulate a tweeter's response in the waveguide. I know people have speculated the signature would be different for different tweeters even with the same waveguide, but perhaps there is a geometry that we could experiment with that would minimize throat reflections or any other factors that prevent identical waveguide influence on differing tweeters.

So here's what we need:

1) Ideas for profiles. Keep in mind with the SLS process, conventional manufacturing restrictions do not apply.

2) Someone to generate the profiles in a legit CAD software that can export .stp or .igs or .x_t files.

3) Someone to manufacture the waveguides. That's me. I'll cover shipping to the measurement site. Whoever does the measuring is welcome to keep the waveguides.

4) Someone to measure a few different common tweeters in the several different waveguide profiles.

C'mon guys. Any takers?

Dan

I'd do the measuring, just don't have the cad software to generate the profiles.

[DIYNut42]

I'm glad you brought this up because I thought about utilizing this combo with 2 of my Klipsch 6.5's in a TMM 2.5 way config. Any chance that would be do-able?

[lunchmoney]

Polyjet would be fine, but I know a vendor who can do SLS for free . Let's get this going. I can make a ton of iterations all with different waveguide profiles. I can make them fast and for free. Unfortunately, the CAD software I have available to me does not lend itself to creating geometry easily, so I won't be able to generate the CAD files myself.

This is a great opportunity to get some good data on the effects of different shaped waveguides and possibly identify a FR signature(s) for a given profile(s) that could be imported into PCD to simulate a tweeter's response in the waveguide. I know people have speculated the signature would be different for different tweeters even with the same waveguide, but perhaps there is a geometry that we could experiment with that would minimize throat reflections or any other factors that prevent identical waveguide influence on differing tweeters.

So here's what we need:

1) Ideas for profiles. Keep in mind with the SLS process, conventional manufacturing restrictions do not apply.

2) Someone to generate the profiles in a legit CAD software that can export .stp or .igs or .x_t files.

3) Someone to manufacture the waveguides. That's me. I'll cover shipping to the measurement site. Whoever does the measuring is welcome to keep the waveguides.

4) Someone to measure a few different common tweeters in the several different waveguide profiles.

C'mon guys. Any takers?

Dan

I can do the cad very easily. I have a lot of experience doing very complex geometries in Solidworks (I actually teach it occasionally). Waveguides would be easy. Here's an example. I'm in...



If you're serious about this, take it offline, send me a PM.

[RINNAV]

I can do the cad very easily. I have a lot of experience doing very complex geometries in Solidworks (I actually teach it occasionally). Waveguides would be easy. Here's an example. I'm in...



If you're serious about this, take it offline, send me a PM.

Lunch, what would you supose the baffle step is like on that one!

Jason

[benchtester]

Yep, looks like it's NLA at the moment.

...

It's shocking, I did buy four recently and machined them to fit the ScanSpeak HDS tweeters. They measured well with minimal "wave guide dip".

I can do the cad very easily. I have a lot of experience doing very complex geometries in Solidworks (I actually teach it occasionally). Waveguides would be easy. Here's an example. I'm in.....

You lucky, lucky b........ I used to used Solidworks occasionally and enjoyed it, my new job requires ProE, and it is horrible

I'll bet that waveguide gives the music a lot of body.

BTW: Zaph posted the coordinates of the MCM waveguide here:
http://www.zaphaudio.com/WaveguideTMM-profile.pdf