Why does qts matter

[ciaonzo 5,000+ posts]

I tend to oversimplify this one in order to make it easy to grasp the concept and discuss. Otherwise, the discussion will never go smoothly.

Look at a free-air frequency response graph and study the low end rollof on the left side, and the inductance rolloff on the right side (often this side is flat because the inductance is not accounted for but there is rolloff, rest assured). Now turn that graph clockwise just a bit until you have some symmetry with the rollof. This is how to visualize Qts.

Qts is total Q product (shape) at Fs. We're simply describing bandwidth with a shape that has a center frequency. The shape is either narrow or wide. Narrow describes HIGH Q and wide describes LOW Q. The driver is resonant and has output on either side of that resonance. In overly-simple terms, Qes describes the control the magnet/coil exerts with a given value, and Qms describes the control the spider/surround exerts, but this is a partnership that leads to Qts. And it changes the moment you put the driver in an enclosure, as was already indicated. If implemented incorrectly, high Q can get "ringy" and low Q can suffer from seemingly not much bass output.

Again, this is a very general approach to the subject but drivers are different today so some of what used to be hard lines for how to implement them has changed a great deal and left us with very blurred lines for which people are producing some very good results with very unorthodox methods. Myself, included. Sometimes you can rely on the motor, sometimes you can rely on the enclosure, but at all times use EQ. That's my advice.

 

[ciaonzo 5,000+ posts]

You dont have a clue. Lamba came up with the shorting rings and how to implement them.

I've seen some very old drivers that had copper sleeves/rings in them. Check out Ted Jordan's work and some other Philips stuff, I believe.
Here, I found a link to one. --> Philips 9710/

 

[The_Quiet_One 10+ year member]

Misspelled it. Forgive me god..

Misspelled what? I was curious what you meant by defining parameter?

 

[Papermaker85 5,000+ posts]

Misspelled what? I was curious what you meant by defining parameter?

what i meant was for years i found technical terms or parameters and very few understood how they affected the loudspeakers realistically/physically. this was 15 or so years ago. now they have sites that are much more defining but still many people failed to understand what happens to a over damped or under-damped signal. to bad im not big into graphics i could draw up alot of stuff..

 

[Papermaker85 5,000+ posts]

 

[ciaonzo 5,000+ posts]

.577 all the way, baby. I even model my vented enclosures to resemble that curve as much as possible. They turn out big, lol.

 

[Papermaker85 5,000+ posts]

.577 all the way, baby. I even model my vented enclosures to resemble that curve as much as possible. They turn out big, lol.

its crazy how people don't realize that they hear most music over-damped.

for instance look at the final Q of say a DD 9515 in 4 cubes.. the QES is so over-damped to get close to a critical damping it **** near needs to be freeair.

now that im more into music i won't be owning any driver that doesn't sound great..

 

[ciaonzo 5,000+ posts]

its crazy how people don't realize that they hear most music over-damped.
for instance look at the final Q of say a DD 9515 in 4 cubes.. the QES is so over-damped to get close to a critical damping it **** near needs to be freeair.

now that im more into music i won't be owning any driver that doesn't sound great..

I think the monster motors all deliver that type of Qes figure. What needs to be done with that is to design a proper enclosure that yields a tuning that is complimentary to the vehicle and the tastes of the end user (regardless of the driver Fs, just something that controls cone motion in the area that you plan to beat the piss out of it) and ideally, I don't mean high tuning. From there, apply a shit ton of power and the necessary EQ (and it will be necessary) to get a balanced and powerful bandwidth. But you're right, all too often guys end up with peaky or lean bass simply because they don't realize what's going on or how to correct it.

 

[ciaonzo 5,000+ posts]

Another way to put that, is to say an ultra low Qes usually means a decent or crazy high BL product that can and should be put to use. EQ is awfully important there because you will need boost on the low end, most likely. Just think of the acceleration factor with that, though.

 

[Papermaker85 5,000+ posts]

If you take the same softparts and just change motors ie alter the b field strenght and play a series of tones you can actually overlap them and see how the waveform is different as the driver plays futher from fs..

 

[ciaonzo 5,000+ posts]

If you take the same softparts and just change motors ie alter the b field strenght and play a series of tones you can actually overlap them and see how the waveform is different as the driver plays futher from fs..

Sure, I think I see what you're saying now. Like they way polypropelene cones tend to smooth over sharp waveforms in the upper midrange? I know that's not the same thing, but the effect may be similar.

 

[Papermaker85 5,000+ posts]

I think your getting the idea..

Where in the waveform of a overdamped signal would be closer to a. Sawtooth wave and the underdamped closer to a square wave.. And after the signal of course the over damped driver is going to "deaden" the oscillation prematurelly while the underdamped wil actually continue the signal emmiting a slighty "delayed" signal from excessive oscillation.

Thats why people say it sounds "tight" and they corralate that with great transient response but its actually poor tranisant response.

 

[ciaonzo 5,000+ posts]

Impulse response. Rise time and decay is what it all comes down to.

Virtually nothing tracks the input signal 100% faithfully. No matter what, every driver and system has character. Just gotta get it to match yours, lol.

 

[Papermaker85 5,000+ posts]

Impulse response. Rise time and decay is what it all comes down to.
Virtually nothing tracks the input signal 100% faithfully. No matter what, every driver and system has character. Just gotta get it to match yours, lol.

What if i told you i am working on building a loudspeaker that automatically corrects the input signal to match the orginal input signal as it was recorded. Ie the driver tunes itself be adjusting mechanical and electrical dampening?

making traisant response almost perfect!

Its as easly as playing the signal then correcting the signal vua feedback then once its adjusted next time it plays the input signal is altered via varible dampening.. Downfall is it has to "store" the modified signal.. But thats not a huge deal as it can be rewritten on the same drive.

 

[LosIsATool 5,000+ posts]

What if i told you i am working on building a loudspeaker that automatically corrects the input signal to match the orginal input signal as it was recorded. Ie the driver tunes itself be adjusting mechanical and electrical dampening?making traisant response almost perfect!

Its as easly as playing tge signal then correcting the signal vua feedback then once its adjusted next time it plays the input signal is altered via varible dampening..

But some how you can't even spell... is this magic speaker going to auto tune itself and adjust for road noise?