Tweeter size as factor in speaker buying? System power response at crossover point?

[whazzup]

Came across this post:
http://www.zaphaudio.com/offaxis.html

The most important criteria in selecting a tweeter is the harmonic distortion on the low end near the crossover point. This is the most audible defining characteristic of a tweeter, more so than top octave frequency response. System power response, while critical at the crossover point, becomes a non-issue higher in frequency.

I understood the comment about the top octave response being less important than imagined, but not quite understanding what 'system power response at crossover point' really means.

Does it mean 3/4" tweeters are more likely to distort / sound worse near crossover frequencies as opposed to 1" ones? Always? Or does it depend more on whether the tweeters are well integrated into the speaker as a whole? Meaning as a layman, I shouldn't be too concerned about 3/4" tweeters (when buying speakers from established brands at least)?

 

[valerianf]

As I modified by myself my speakers including the crossover filter, I have used different types of tweeter.
1" dome of different brands 92-95dB efficiency with a crossover around 2.3-2.5 khz.
A 3/4" Titanium bullet tweeter Audax PR130I1 106dB efficiency with a crossover at 7 khz.
The bullet tweeter was amazing as you can hear every micro-detail in the high frequencies, with a great purity.
Alas it does not exist anymore.

But you need to understand that it is not the for the same type of speaker.
With the bullet tweeter you need at least a 3 ways speaker, with a small size midrange able to go up to 7 khz (11cm or very good 13 cm diameter) without coloration.

Usually, for a random speaker, I am using a 1" dome.
The problem is to find a good one with a very refined sound.
You need to listen it some time before making a choice.

For high power handling, you need a tweeter with ferrofuild cooled voice coil.

 

[whazzup]

I guess what I'm trying to understand is, assuming the same material / quality, are 1" tweeters generally always better than 3/4" tweeters, when considering 2-way speakers? And if that's the case, is it because of the larger surface area of a 1"?

 

[MZKM]

I guess what I'm trying to understand is, assuming the same material / quality, are 1" tweeters generally always better than 3/4" tweeters, when considering 2-way speakers? And if that's the case, is it because of the larger surface area of a 1"?

If you want good bass performance, then yes. Unless you do some crazy waveguides or whathaveyou, a 3/4” tweeter is going to need to be crossed well above where the woofer starts to beam, thus leading to reduced energy in the crossover region.

The Buchardt S400 uses a 3/4“ tweeter and a decent waveguide and it still has the above stated issue.

 

[whazzup]

If you want good bass performance, then yes. Unless you do some crazy waveguides or whathaveyou, a 3/4” tweeter is going to need to be crossed well above where the woofer starts to beam, thus leading to reduced energy in the crossover region.

The Buchardt S400 uses a 3/4“ tweeter and a decent waveguide and it still has the above stated issue.

Thanks for the interesting insight! Given the pricepoint of the S400, why wouldn't they use a 1" tweeter instead then? It shouldn't cost that much more right?

 

[MZKM]

Thanks for the interesting insight! Given the pricepoint of the S400, why wouldn't they use a 1" tweeter instead then? It shouldn't cost that much more right?

They said the liked the wider dispersion the 3/4“ gave in the upper treble, so a wider sweet-spot.

 

[valerianf]

If you compare Amirm measurement with the S400 (3/4" tweeter ) and the measurement with the Revel M16 (1" tweeter) you will notice that the S400 response curve has a deep at 2Khz that is not present for the Revel.
1" tweeter is better suited for a two way speaker because of the lower crossover frequency.

 

[gene_stl]

the tweeter size affects dispersion. The bigger they are the lower will be the frequency that they stop radiating into half space and start beaming.
A larger diaphragm can drive more air at the lower frequencies of the drivers range than a smaller one.
If you want real top end you should have a one inch or less tweet.

The term "Bullet Tweeter" often describes "Ring Radiators which are horns and have very narrow radiating slots (in a circle) These are capable of high efficiency and high output. But many audiophiles don't want to actually hear high frequencies.

 

[bigjacko]

The implementation can also make a difference. Not all 1 inch tweeter have same dispersion, same for 3/4 inch. All tweeters have different amount of distortion, some 3/4 can have lower distortion than 1 inch. The only thing that is the truth is measurement.

 

[valerianf]

Smaller is the tweeter diameter higher need to go the crossover cutting frequency.
It may be an issue for the other speaker.
I got two different speakers with a compression tweeter.
The high frequencies were amazing (clarity, details) but what a pain regarding the crossover cutting frequency.