Is my Phase too fat?

[Wushuliu]

Been working on my first (well technically second) design. MTM with Eclipse and Satori TW29. I use REW for measurements and primarily WinPCD for the XO work. Since most folks here use PCD I imported into that for the screenshots. I like what I have so far but not sure how this phase looks. Bad? good? Weird? I use the min phase generated in REW.

[Chris Roemer]

While not "perfect" tracking (for LR2/4), it certainly isn't bad between 200Hz and about 4k (before diverging).

[isaeagle4031]

That isn't too shabby. Try adjusting the tweeter values just a bit and they will come right into line.

What is the lcr for on the woofers?

[Wushuliu]

What is the lcr for on the woofers?

For the peak as discussed in that previous thread.

[isaeagle4031]

The small cap did not knock that out?

[dcibel]

Make sure you have entered in the driver sizes, then you can simulate off-axis response and judge for yourself if the phase response is acceptable.

Basically, if the phase is aligned on-axis, then the response will only drop as you move off-axis. If the phase is not aligned on-axis, then off-axis it will align, and at this angle the output will increase. This is because the alignment axis of the phase is not straight ahead, but at a slight angle, which may be of some benefit if the intended use for the speakers is above or below the listener.

[Wushuliu]

That isn't too shabby. Try adjusting the tweeter values just a bit and they will come right into line.

So far it seems I would have to go from second order electrical to third on the tweeter to get near-perfect phase tracking. But do I need to? (Guess I will just add that cap and see..)

[Wushuliu]

The small cap did not knock that out?

Yeah, but I have the LCR parts on hand and just kept them there as part of the learning experience.

@decibel, will do.

[ernperkins]

You have fine frequency response (FR) throughout the crossover region so I wouldn't obsess over the phase. It's easy to caught up in the "I must have a super deep null" train of thought and forget a main reason for phase tracking is to prevent FR irregularities around the crossover region. Good luck with your project!

PS - I assume you measured/calculated the acoustic offset and entered that into PCD (as Z offset) along with the Y offset.

[isaeagle4031]

Yeah, but I have the LCR parts on hand and just kept them there as part of the learning experience.

@decibel, will do.

Understandable. As far as 3rd order, given the somewhat low xover point, I would use that as a minimum anyway

[Wushuliu]

Understandable. As far as 3rd order, given the somewhat low xover point, I would use that as a minimum anyway

Why? To protect the tweeter?

[xmax]

Which version TW29? None of them like to go that low, they have a natural roll off that starts around 4K,
but then a large peak at around 1500, even if you get decent measurement it will not sound very good.

Also what are you basing your cap/coil ratios on?

All the SB stuff can sound fantastic but the tweeters can get naughty below 2K if not very sharply
filtered.

[xmax]

You see even the much cheaper Seas (and the Transducer Labs) has a lot less distortion at 1K.
The SB tweeters are some of the best but I would never cross them below 3K at 12 or more dB
per octave.

[Wushuliu]

Huh, I thought one of their advantages was that they could be crossed low.

Can't cross below 3k?

[dcibel]

Here's the TW29 soft dome:
http://www.audioxpress.com/article/t...gh-end-tweeter

And here's the Be edition:
http://www.audioxpress.com/article/t...m-dome-tweeter

You have increasing distortion below 2kHz, but it is purely 2nd order. I wouldn't hesitate to use the TW29 with a 2nd order 2kHz crossover, 4th order acoustic rolloff, but no lower.