FAST or STAFT (WAW or STAW) Which is Better?

[AllenB]

Interesting crossover. What does the vertical look like with both drivers playing (polars)?

 

[xrk971]

A thank you to Astrojet for offering to send me a pair of A12PW drivers. Looking forward to testing these with a tweeter. Hopefully I can get them to fit an existing test box. Or I might have to make a new baffle.

 

[norman bates]

About the maggies........ (post 40)

I agree, i had some accoustat (electrostats) panels, sounded great 6' from the front wall.

 

[zman01]

A thank you to Astrojet for offering to send me a pair of A12PW drivers. Looking forward to testing these with a tweeter. Hopefully I can get them to fit an existing test box. Or I might have to make a new baffle.

X,

Look forward to the results from your experiments. This will be interesting, as the this "bass-wide" driver looks like a good candidate for wide-band crossed high.

And thanks to Astrojet!

 

[planet10]

used a modified inverted passive Harsch XO to achieve semi-transient perfect behavior

Given the larger than quarter wavelength spacing between tweeter & midBass this will only hold for one position in space.

Adding a superTweeter to a nearly FR driver has been done forever. And an XO 5-6KHz is a very common point for the tweeter to take over. I’ve had a number of enjoyable speakers with similar execution.

And the addition of woofers to help with the low end is also common.

This should maybe be in the MultiWay section.

dave

 

[billshurv]

I suspect optimal requires limiting the low end to 300Hz to 500Hz. Cones generate treble through non-pistonic break-up modes and start to narrow their dispersion. I suspect optimal results limits the upper end to 1.5kHz to 3kHz. If you can cover the decade from 300Hz up to 3kHz cleanly with decent sensitivity, strong output, lowish distortion and reasonably well behaved dispersion without using up half of your living room then you are doing Extremely well.

Well my current main speakers (Apogee hybrids) do 450Hz up on the ribbon, but do roll off a bit above 15kHz. What is interesting is, a few years back, before I replaced the ribbons, one of them would cut out now and again and when I was limited to just the woofer with LR2 roll off much of the music was preserved and it wasn't the mush I would have thought there to be. So I'm left unsure as to the optimal range for the core driver.


I had a peek at the spec for the Purifi PPT4.0 to see if that offers anything for high roll off than the 6.5. I'm no expert but the rising response above 3kHz along with a big increase in distortion don't appear to work in its favour.

 

[planet10]

Nice work X,
I have been thinking about using your little monitor like this speaker, which I lost in a house fire.
Keep listening and let us know your findings. Sorry, didn't mean to go OT.

Fried C + woofer. A derivation of the earlier Model M (the model H with 2 boxes instead of 3. I had some influence on the shape of the C. In its day, a superb loudspeaker.

dave

 

[planet10]

Alpair 12PW

A midBass driver that is underappreciated.

We use a pair with Alapie 7.3eN. No need for a tweeter. And the issues they bring with wild FR depending on wher eyour head is.

In a Woden ML-TL they reach to the mid20s with ease. XO with this driver could be anywhere between a couple hundered all the way up to 5k. The above use 250 Hz.

dave

 

[scottjoplin]

No need for a tweeter. And the issues they bring with wild FR depending on wher eyour head is.

What do you mean, exactly?

 

[planet10]

A tweeter would degrade performance up top.

dave

 

[scottjoplin]

How and why?

 

[planet10]

The A7.3eN has good top, adding an XO and a physically distanced tweeter (ie anything over a 1/4 wavelength is physically distanced) screws up both the FR (in most places) and you lose the coherence/seemlessnes of the FR.

dave

 

[scottjoplin]

Are you referring to comb filtering?

 

[Bigun]

This should maybe be in the MultiWay section.

dave

Really? when is a FAST a two way and when does adding a super tweet make it a 3 way ?

How about, providing we are using a nominal full range driver and not a driver sold as a mid, we get to identify it as suitable for the full range forum. Perhaps, in addition, it has to cover a decade. Perhaps the XO should be low order, or absent.

I think most people get a sense when a speaker is predominantly based on the characteristics of a full range driver.

 

[scottjoplin]

Sounds reasonable. I think the discussion of options is just recognizing the fact that "fullrange" is a misnomer in the first place.

 

[planet10]

Are you referring to comb filtering?

It could be descibed as such.

Dannie RItchie did good video of the issues.

dave

 

[scottjoplin]

He doesn't mention audibility, that's what matters, and it's not as audible as measurements might suggest. It's a good idea to read about Toole's investigations into that.

 

[planet10]

I have read toole (many times). I have also played a lot with sTs, they sometimes work, sometimes not.

dave

 

[scottjoplin]

It appears a lot of "smoothing" happens in the brain connected to two ears that doesn't bare much resemblance to what a microphone measures at one point in space.

 

[Bigun]

...there are many violins in an orchestra, they are neither time aligned or separated by less than W/4