There are a few comments about it in Zaphs new design.
http://www.zaphaudio.com/ZD5.html
He tilts the on axis response up a bit to compensate for the fast falling off-axis response.
If you don't need a very low Xover it seems like a great tweeter for the money.
http://www.zaphaudio.com/ZD5.html
He tilts the on axis response up a bit to compensate for the fast falling off-axis response.
If you don't need a very low Xover it seems like a great tweeter for the money.
It cannot be proven and will remain a theory - but ofcourse it helps a lot when respected people like that claims it to be so, and furthermore when people here persists to repeat it all the time
And to practice it in reality is depending on steep slopes, which then rules out some other good sounding options
And you will still have offaxis rolloff outside its passband and unavoidable offaxis phase problems still - nothing you can do about that
And to practice it in reality is depending on steep slopes, which then rules out some other good sounding options
And you will still have offaxis rolloff outside its passband and unavoidable offaxis phase problems still - nothing you can do about that
Hi all,
Since the XT25 is one of my favorite tweeters, I thought I'd take a moment to say why. As Tenson noted some of that explanation is in my ZD5 project.
I do think top octave off axis response is highly overrated. I'm not the kind of guy who walks around the listening room. And for the guy who settles for a far off axis listening chair, what's going on in the top octave should be the least of your worries.
If top octave off axis really was that important, full range drivers would not be popular at all.
What's more important but often neglected is the off axis response of a system in the midrange. The midrange is relfected back into the room, unlike the top octave which is mostly absorbed by the first surface. (drywall, carpet, etc) Midrange room response contributes to overall tonality and having a poor power response can mean an edgy and forward sound even when the sweet spot measures flat on axis.
For me, all a tweeter has to be is good enough in the top octave, and that means I only care about maybe the first 15 degrees off axis. Beyond that, the tweeters other characteristics become much more important. For the XT25, I love it's complete lack of tall order harmonics. For me it's the "anti-ribbon" and offers one of the cleanest top ends I've heard. For everyone else, there's the Hiq OW tweeters... they sound like ribbons and have good off axis response too.
All that said about the XT25, I do think the new Peerless HDS is at least as good or better. I just haven't had a chance to use it in a project yet. The XT25 is easier to work into a LR2 response curve due to it's extended low end. But for just about any LR4 system, the HDS is going to be excellent.
Regards and happy holidays,
John
Since the XT25 is one of my favorite tweeters, I thought I'd take a moment to say why. As Tenson noted some of that explanation is in my ZD5 project.
I do think top octave off axis response is highly overrated. I'm not the kind of guy who walks around the listening room. And for the guy who settles for a far off axis listening chair, what's going on in the top octave should be the least of your worries.
If top octave off axis really was that important, full range drivers would not be popular at all.
What's more important but often neglected is the off axis response of a system in the midrange. The midrange is relfected back into the room, unlike the top octave which is mostly absorbed by the first surface. (drywall, carpet, etc) Midrange room response contributes to overall tonality and having a poor power response can mean an edgy and forward sound even when the sweet spot measures flat on axis.
For me, all a tweeter has to be is good enough in the top octave, and that means I only care about maybe the first 15 degrees off axis. Beyond that, the tweeters other characteristics become much more important. For the XT25, I love it's complete lack of tall order harmonics. For me it's the "anti-ribbon" and offers one of the cleanest top ends I've heard. For everyone else, there's the Hiq OW tweeters... they sound like ribbons and have good off axis response too.
All that said about the XT25, I do think the new Peerless HDS is at least as good or better. I just haven't had a chance to use it in a project yet. The XT25 is easier to work into a LR2 response curve due to it's extended low end. But for just about any LR4 system, the HDS is going to be excellent.
Regards and happy holidays,
John
I pretty much have to agree. The xt series are great tweeters. You get a bit extra 2nd order products, but the tradeoff is some of the lowest higher order distortion out there. I wouldn't say the off axis performance isn't important--I think if you're relatively nearfield and on axis this tweeter is outstanding. I think that you can make an arguement that if you're way beyond the critical distance and/or off axis, you may want something like the HDS.
I think either tweeter can make an excellent design and any perceived differences would likely be implementation differences
I think either tweeter can make an excellent design and any perceived differences would likely be implementation differences
I think the XT's are excellent tweeters as well.
There are probably a thousand different parameters that are important to speaker design. Off axis is one of them. There is quite a bit of evidence that it may be very important (Toole, Geddes, Linkwitz, Danley, etc.).
I don't believe you can isolate just HF and say it is overrated to want it to track the on axis as much as possible, although you want power response (and DI) to taper upwards as not to sound overly bright in a typical listening room.
The extra radiated power at HF will be audible to varying degrees at the typical non-nearfield listening position as the room influences the sound.
How much you might "rate" this in order of importance would be somewhat subjective. I don't consider it overrated at all.
The importance of off axis has little or nothing to do with walking around the room or sitting off axis. Controlled directivity isn't for better sound walking around, it's for better sound at the normal seated listening position. Fullrange drivers may be an excellent argument as why off axis is important. The so called "helper" tweeter is clear evidence that many FR users can hear the HF power response free fall... and feel the need to do something about it .
Merry Xmas,
AJ
There are probably a thousand different parameters that are important to speaker design. Off axis is one of them. There is quite a bit of evidence that it may be very important (Toole, Geddes, Linkwitz, Danley, etc.).
I don't believe you can isolate just HF and say it is overrated to want it to track the on axis as much as possible, although you want power response (and DI) to taper upwards as not to sound overly bright in a typical listening room.
The extra radiated power at HF will be audible to varying degrees at the typical non-nearfield listening position as the room influences the sound.
How much you might "rate" this in order of importance would be somewhat subjective. I don't consider it overrated at all.
The importance of off axis has little or nothing to do with walking around the room or sitting off axis. Controlled directivity isn't for better sound walking around, it's for better sound at the normal seated listening position. Fullrange drivers may be an excellent argument as why off axis is important. The so called "helper" tweeter is clear evidence that many FR users can hear the HF power response free fall... and feel the need to do something about it
.Merry Xmas,
AJ
AJinFLA said:
Note to everyone: I said top octave off axis response is overrated. I didn't say off axis in general is overrated. Power response, particularly near the crossover region in multiway systems is underrated and often ignored. Most of Toole and Geddes writings that I have read were concerns over power response and transitions between woofer and tweeter.
The important part of power response is the midrange. This is because the midrange is reflected back into the room. The top octave is not. I've seen absorption response plots of drywall and carpet.
Note that I'm not saying top octave off axis response is completely unimportant, but it's more of a listening position limitation than a "performance" limitation.
I just wanted to make sure everyone is clear on what I said and meant.
John
I do not neglect the importance of off axiss response of a mid driver
But I find that at the moment every one insists on a 2khz cross point, thinking that it will "save the day"
I still think that the unexperienced builder will be able to build a much better speaker with higher crossover point
Well, actually TroelsGravesens latest 2-way creation with 8" drivers have higher crossover point with very simple filter .... and he seems to love it
But I find that at the moment every one insists on a 2khz cross point, thinking that it will "save the day"
I still think that the unexperienced builder will be able to build a much better speaker with higher crossover point
Well, actually TroelsGravesens latest 2-way creation with 8" drivers have higher crossover point with very simple filter .... and he seems to love it
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