And your point is ? I know what superposition of two sine-waves looks like. How specifically is it relevant ? The mid-bass drivers excursion is the superposition of the two sine waves, but because it only has to generate half the bass, the 100Hz portion of the cone excursion is halved while the 1Khz portion stays the same. So what ? That doesn't help your position at all. Far from it.
Making random statements that aren't connected doesn't form an argument.
Bandwidths being out of phase ? Could you please restate that in a way that makes some sort of sense and then I will attempt to respond to your point.
Better yet, you can explain to me how something vibrating at 100Hz can be in tune with 1KHz.
There is more to phase then making sure you got the "+" and "-" connected properly on your speakers.
So, nothing meaningful for me to attempt to respond to in this post then, just more random unconnected statements. Ok then.Better yet, you can explain to me how something vibrating at 100Hz can be in tune with 1KHz.
There is more to phase then making sure you got the "+" and "-" connected properly on your speakers.
Alvis it is understandable why people think you are trolling. I find it hard to not come to the same conclusion myself. If you are not trolling then I suggest you re-read and rethink some of the previous posts. If you are trolling then give it up now or you will end up in the bin or banned. See rule number 2 http://www.diyaudio.com/forums/site-announcements/167561-diyaudio-rules.html
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So, nothing meaningful for me to attempt to respond to in this post then, just more random unconnected statements. Ok then.
No, explain how 100Hz and 1KHz can be in phase.
While a bass note is slowly moving in and out, the fast notes move the driver in and out faster, they can switch polarities/directions many times while the driver is in the positive or negative region of the bass cycle.
They are phased indepentently.
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Explain how this sentence on its own forms a meaningful question and what its relevance is to the discussion. I can't answer it when I don't understand the intent of the question.
Yes, and this is called frequency/phase modulation, something that also happens with a 2 way system with a mid-bass driver, so what is your point exactly, given that a 2.5 way system will have less frequency/phase modulation of midrange by bass for the SPL due to the halved excursion of the mid-bass driver ?
Again, you are arguing against your own position, not for it.
And by the way, I found your link:
hi-fi avenue: JBL Everest: Summit of sound?
You probably forgot to mention this part:
The music just leaps out in an explosive and impactful manner in an ultra-dynamic way. There is no overhang, no prolonged notes - just quick, sudden spurts of music.
That is undoubtedly from all that midrange leaking out the bass driver.
It's not that hard to grasp, also I don't know why you must keep referencing 2-ways to support your 2.5 argument.
It's simple, the added or unbalanced bass pressure will add peaks and dips to the mid range depending on the time alignment of the source material.
I'm sorry, it does not get any simpler than that.
Putting open backed mid rangers and woofers in the same enclosure is poor practice, especially when they are playing different material.
Hi,
Knowing what I'm talking about helps. Who has a nasty attitude
I'l leave others to decide, but you do protest far too much IMO.
rgds, sreten.
Arrogance is generally the remit of the ignorant.
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Forget about speakers that are the same size for a moment.
OK how would you go about combining a 4" and 12" openback speakers in the same cabinet at different frequencies?
The ball is in your court, tell us how this is optimally done, and how the imbalance won't tear the speaker from the surround?
OK how would you go about combining a 4" and 12" openback speakers in the same cabinet at different frequencies?
The ball is in your court, tell us how this is optimally done, and how the imbalance won't tear the speaker from the surround?
Both of these comments betray your lack of understanding of how a 2.5 way works. You would never use different size drivers in a 2.5 way, so it's pointless to even discuss the scenario.
A 2.5 way is not a 3 way without a separate midrange enclosure.
what midrange ?
there is none
both are woofers
the problem does exist, ofcourse
as it does in any 2way
so even if you split up the box, you still have the known problem of a woofer trying to midrange while moving to play bass
its still a woofer trying to play midrange
nothing you can do about it
other than doing a 'standard' 3way, where the problem is minimal, if crossed properly
what midrange ?
there is none
both are woofers
the problem does exist, ofcourse
as it does in any 2way
so even if you split up the box, you still have the known problem of a woofer trying to midrange while moving to play bass
nothing you can do about it
other than doing a 'standard' 3way, where the problem is minimal, if crossed properly
The one playing higher frequencies has been referred to as the mid range.
It's not a problem of a woofer trying play midrange while playing, it's that the addition of that second "woofer" grossly distorts what the mid range FREQUNCIES will sound like compared to by itself.
You guys can perform this experiment easily.
Alvin, there is no added sound pressure because the box volume is doubled with two woofers
pressure inside the box stays the same
or else the sim/calc would tell you
magnet/motor power takes complete control, no matter what
and the bass frequencies dominate completely in that respect
midrange frequencies have no influence on the larger bass frequencies
so its always bass nodes that will dominate the driver, both of them
and the exact same for both, whether they share the volume, or are seperated
its no different from a 2way, in that respect
pressure inside the box stays the same
or else the sim/calc would tell you
magnet/motor power takes complete control, no matter what
and the bass frequencies dominate completely in that respect
midrange frequencies have no influence on the larger bass frequencies
so its always bass nodes that will dominate the driver, both of them
and the exact same for both, whether they share the volume, or are seperated
its no different from a 2way, in that respect
There is no imbalanced bass pressure. Both drivers produce exactly the same pressure inside the cabinet. Their excursion will be identical, and so is their cone surface area.
Now we calculate the volume of a cylinder...
V=pi*(r^2)*h
Where h is the peak to peak displacement of the cone
r is the cone radius.
The volume of the cabinet seen by each driver is exactly equal: they share.
Lets make the numbers very easy so we can see what's going on here.
The p/p displacement of the cone is 10mm, and the radius is 10cm.
So the volume displaced during one cycle is 3.14x10^-4 cubic metres.
Lets give the cabinet a volume of 0.0314 cubic metres. 31.4 litres sounds okay, right?
The percentage of the volume of the cabinet that the driver displaces is 1% (Vd/Vc).
Okay, so that's one driver in 31.4L.
Lets try two drivers!
V=pi*(r^2)*h*2
We'll keep h and r the same again. V now = 6.28x10^-4 cubic metres.
We'll also double the cabinet volume so that both drivers can be accomodated. It's now 62.8L.
Lets see...
Oh look, the percentage of the volume of the cabinet displaced by the drivers is still 1%.
The percentage change is the pressure inside the cabinet.
It's the same both times.
There will therefore be no modulation of one driver on the other, because they share the cabinet volume.
Q.E.D.
Chris
PS - sorry to everyone else about this post being so patronising. I wanted to make it perfectly clear.
The bass is imbalanced in relation to the midrange. The added speaker makes it imposible for the midrange frequencies to react properly to the enclosure. The enclosure no longer has static consitant pressure so far as the mid range is concerned.
Your math is meaningless, your thinking two drivers drivers in the same box doing the same thing, this is not the case here.
Really?, nobody can answer a simple question without deflecting and condescending attacks?
Your math is meaningless, your thinking two drivers drivers in the same box doing the same thing, this is not the case here.
Really?, nobody can answer a simple question without deflecting and condescending attacks?
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