Audax TW025A28 Testing with Waveguides

[davepellegrene]

A fine gentleman from Finland ordered a set of these and had them sent to me for some waveguide testing after mentioning them from Jeff B's thread.
http://www.madisoundspeakerstore.com...-dome-tweeter/

They have a small surround which made it nice for me to get in close to the dome which really helps out on the top end.

This is in my 165mm x 115mm guide using a 1" throat. It is 1 3/8" deep.



This is with the face plate removed. You can see how small the surround is. I think this is a great advantage when fitting the guide over the surround.




They are advertised with a 94 db sensitivity but I think they are closer to 92 dbs from some comparisons I made against a few other tweeters I know well. Other then that they do really well in the waveguides I've tested so far. Distortion test look like they would be good down to about 1.6 kHz.

10" x 14" Flat Baffle 0-90 degrees



Distortion on the flat baffle.





This is the 165mm x 115mm Elliptical guide 0-90 degrees horizontal axis





Same 165mm x 115mm guide EQ'd flat 0-90 degrees Horizontal



This is Flat baffle (red) vs 165mm x 115mm guide (black) on axis





This is my 8" round guide with a 1" throat. It is 2" deep.




I'm going to test these in a larger Elliptical guide (8x5) and see how they do. I'm thinking about trying these out with the B&C 8NDL51 8" in a sealed two way with the 8" x 5" or 6.5" x 4.5" Elliptical guides.
http://www.parts-express.com/pe/show...number=294-649

Not sure on the woofer though yet.

Dave

[davepellegrene]

Re: Audax TW025A28 Testing with Waveguides

I ran across these will looking at the Pro woofers. I've not heard of them but they look pretty nice.
http://www.parts-express.com/pe/show...number=294-828


Dave

[Wolf]

Re: Audax TW025A28 Testing with Waveguides

I ran across these will looking at the Pro woofers. I've not heard of them but they look pretty nice.
http://www.parts-express.com/pe/show...number=294-828


Dave

I've looked at those many a time....

Jealous,
Wolf

[craigk]

Re: Audax TW025A28 Testing with Waveguides

listened to them in the pbn liberty speaker and they are very good tweeters.

[davepellegrene]

Re: Audax TW025A28 Testing with Waveguides

I've looked at those many a time....

Jealous,
Wolf

Your thoughts?

Dave

[Squidspeak]

Re: Audax TW025A28 Testing with Waveguides

A fine gentleman from Finland ordered a set of these and had them sent to me for some waveguide testing after mentioning them from Jeff B's thread.

They have a small surround which made it nice for me to get in close to the dome which really helps out on the top end.

This is in my 165mm x 115mm guide using a 1" throat. It is 1 3/8" deep.



This is with the face plate removed. You can see how small the surround is. I think this is a great advantage when fitting the guide over the surround.




They are advertised with a 94 db sensitivity but I think they are closer to 92 dbs from some comparisons I made against a few other tweeters I know well. Other then that they do really well in the waveguides I've tested so far. Distortion test look like they would be good down to about 1.6 kHz.

10" x 14" Flat Baffle 0-90 degrees



Distortion on the flat baffle.





This is the 165mm x 115mm Elliptical guide 0-90 degrees horizontal axis





Same 165mm x 115mm guide EQ'd flat 0-90 degrees Horizontal



This is Flat baffle (red) vs 165mm x 115mm guide (black) on axis





This is my 8" round guide with a 1" throat. It is 2" deep.




I'm going to test these in a larger Elliptical guide (8x5) and see how they do. I'm thinking about trying these out with the B&C 8NDL51 8" in a sealed two way with the 8" x 5" or 6.5" x 4.5" Elliptical guides.
http://www.parts-express.com/pe/show...number=294-649

Not sure on the woofer though yet.

Dave

Dave do you have any Idea how low these could cross without a waveguide?

[davepellegrene]

Re: Audax TW025A28 Testing with Waveguides

listened to them in the pbn liberty speaker and they are very good tweeters.

Good to hear.

Dave

[davepellegrene]

Re: Audax TW025A28 Testing with Waveguides

Dave do you have any Idea how low these could cross without a waveguide?

F(s) are at 1153 Hz.

Dave

[davepellegrene]

Re: Audax TW025A28 Testing with Waveguides

Here are the results for the 8x5 Elliptical guide. It measures 1-3/4" deep with a 1" throat.

I'm getting about 2 dbs gain on the bottom end over the 6.5" x 4.5 guide.



EQ'd flat and rolled off on the bottom end until distortion was flat at 92 dbs. So I would say this is the usable FR in this guide.



This is the distortion plot with the EQ'd graph from above.




Dave

[PWR RYD]

Re: Audax TW025A28 Testing with Waveguides

I don't seem to remember seeing any DIY projects using Audax tweeters. At least not any recent projects. Are they not a good value or something? The one you are testing is about twice the cost of an RS28a/f. How would you say they perform compared to the RS tweeters?

[davepellegrene]

Re: Audax TW025A28 Testing with Waveguides

I don't seem to remember seeing any DIY projects using Audax tweeters. At least not any recent projects. Are they not a good value or something? The one you are testing is about twice the cost of an RS28a/f. How would you say they perform compared to the RS tweeters?

Good Question. I haven't seen or heard one either. Good reason to try them out. I was interested in them for their hi sensitivity. Then testing them in guides they did really well.

Here is a comparison between the RS28F(red) in an 8x4 waveguide and The Audax(black) in the 8x5 waveguide.The RS did not do well in the 8x5 so I don't have a direct comparison. I was able to get boost up to about 10 kHz with the RS28F but then it dropped off pretty quickly. Probably because of the 1-1/8" dome. The Audax is about 5 dbs higher in sensitivity and holds it all the way out. So flattening both drivers from about 12kHz down to their XO point the Audax would stay 5 dbs more sensitive. It also has better controlled directivity. Looking around the 2 kHz area you can see the Audax is 5 dbs higher in sensitivity but is reduced at 60 degrees off axis by about 8dbs as the RS28 is only about 5dbs. So in other words from 2 - 12 kHz the Audax holds a flatter FR at each off axis measurement. The RS28F will cross lower so that is an advantage. I'm assuming this is due to the larger dome which gives up a little on the top end. So is the Audax worth the extra money. Guess that's up to the end user. I haven't' heard the Audax so I couldn't tell you.



Dave

[foxfire3]

Re: Audax TW025A28 Testing with Waveguides

Dave,

Just curious what you're using to EQ the response above in order to obtain such a flat response?

Thank you...

[davepellegrene]

Re: Audax TW025A28 Testing with Waveguides

Mini DSP taking measurements from 1 meter gated at 5ms.

Dave

Dave,

Just curious what you're using to EQ the response above in order to obtain such a flat response?

Thank you...

[markk]

Re: Audax TW025A28 Testing with Waveguides

Very interesting Dave. I have a pair of the TW025A18 that I've never done anything with. The dome and surround dimensions and likely the same. I'll try to pull these out and test them

[mzisserson]

Re: Audax TW025A28 Testing with Waveguides

TW025's are amazing tweeters. The issue is you cannot cross them below 1K. They need a high-ish x-over point. It is a sad side effect of not being the flavor of the month.