Response to an impulse of a driver

[ginetto61]

Hello !

Just a straight question
Is there any TS parameter of a driver that can be related to its behaviour in the impulse response test ?
For behaviour I intend rise time and settling time
Maybe the Qts ?
Lately I have been intrigued by fast reacting drivers and I am eager to learn something
I read for instance that electrostatics and ribbon are exceptionally fast transducers

Thank you very much indeed
Kind regards,
gino

[john k...]

T/S parameter tell you about how the system decays. Nothing about rise time.

[Charles Darwin]

Which bit tells about the decay?
Does it take into account the difference in decay between active and passive crossovers which may be preceding the driver or the difference in damping factor between amps?

[ginetto61]

Originally Posted by john k...

T/S parameter tell you about how the system decays.
Nothing about rise time.

Thanks a lot for your kind and helpful reply
Which TS parameter tells us about the decay ?
I understand that the only way to know the driver rise time is to measure it.
Is that correct ?

I would like to explain a little my curiosity
I listened some days ago to a pair of quad ESL 63 electrostatics
To make it short I have never heard a better performance in the midrange from a speaker
Then I asked to someone who knows them
It seems that at least one of the reason of this unbelievable performance is due to the fact that the moving mass of the driver is very low and this makes the driver extremely fast reacting to any kind of impulse
Given that the driver in the ESL63 is particular I am looking for a dinamic driver that could approach that kind of performance
To eliminate any other problem I intend to use an active crossover
In this way I can drive the driver directly with nothing in between except a cable

I was amazed during a movie to listen to sound effects that seem almost the real thing.
When someone knocked at a door on the left I looked at my door
I do not think a sound can be more real than this
Very very impressive

You might ask, why do not take a pair then ?
Mostly because they do no fit my room ... they are so big
But if space was not a problem I think that I woudl try to find a pair, adding maybe a bass unit per side

Thanks a lot and kind regards,
Gino

[ginetto61]

Originally Posted by Charles Darwin

Which bit tells about the decay?
Does it take into account the difference in decay between active and passive crossovers which may be preceding the driver or the difference in damping factor between amps?

Thanks a lot for your reply
Well from some point I have to start
and I said to myself, why not to start from the driver ? selecting it on the basis that its mechanical properties ?
I want a "fast" driver
It is the only way, leaving aside for the moment of the remaining, to get a good response to transient
If the driver is not fast enough you cannot make it faster
Then I would like to skip on the crossover
I intend to use active multiamplification and high damping factor amps (I have them) to drive the drivers
I am looking for an electrostatic performance but with dinamic driver
I imagine that these kidn of drivers should have low moving mass and high power magnet

Maybe I am mistaking but tehre should be at least a qualitative relation between the Qts and the rise time in the impulse response test
I still haven't found what I am looking for (U2)
For me that English is not my first language songs are always a good help
I Can't Get those quad esl 63 Out Of My Mind
Never heard something of more real ... never
Of course they have their limits .. but within them .. they must be heard

Kind regards,
gino

[john k...]

Originally Posted by Charles Darwin

Which bit tells about the decay?
Does it take into account the difference in decay between active and passive crossovers which may be preceding the driver or the difference in damping factor between amps?

Qts. Drives have 2nd order high pass characteristics. Qts<0.5 means that for a positive pulse the decay will undershoot zero and then decay to zero exponentially from below. For Qts>0.5 the decay will be a damped sine function (ringing). The amplitude and length of the sine decay will depend on Qts. High Qts yields higher amplitude and linger ringing.

This has no connection to the crossover.

Rise time depends on the high frequency cut off of the driver (or crossover). But none of these have much connection with what is typically referred to as a fast driver. Being fast is a subjective term and if you ask a dozen people what it means you will probably get a dozen different answers.

[Ron E]

Isn't decay related rather to Qtc, the system value rather than the driver?

Diaphragm mass in a Quad is reportedly 3 milligrams, they are about 0.7x1 meter in size, so the air load mass on the diaphragm is around 8*0.5^3*1.2/3=0.4kg , or 400 grams, about the weight of 3 to 4 12" woofers.... So it isn't mass...

The sound of quads might be due to any number of things:
lack of box colorations
Large area radiator having low excursion so less modulation distortion
Dipole radiation pattern excites the room differently

Fast is a subjective term, and it doesn't correlate with any known measurement. One person will say a certain speaker is fast and another who uses the word will not. In my experience, it seems that the word fast is used to talk about speakers that don't have much bass, sometimes apologetically, as in: "it doesn't have much bass, but it is fast..."

[Rudolf]

Originally Posted by ginetto61

I listened some days ago to a pair of quad ESL 63 electrostatics
To make it short I have never heard a better performance in the midrange from a speaker
I was amazed during a movie to listen to sound effects that seem almost the real thing.
When someone knocked at a door on the left I looked at my door
I do not think a sound can be more real than this
Very very impressive

Did you ever listen to other dipoles of some decent quality? Could it be that it is not the quality of the driver but the working principle, which made that impression?

[Pano]

I think big dipole is part of it - Magnapan has a similar sound. But those ESLs with the right amp are just amazing.

[ginetto61]

Originally Posted by panomaniac

I think big dipole is part of it - Magnapan has a similar sound.
But those ESLs with the right amp are just amazing.

Hello !
I did some search about the speakers that amazed me so much
And found this

Stereophile: Quad ESL-63 loudspeaker

First of all I am everything but an expert but just look at the impulse, step and square wave response
I would like to ask, are these normal results or are quite exceptional ?
Surely the absence of a crossover is part of the result
I remeber to have seen how a square wave was modified after passing through a crossover network


Regarding the quality of the amp ... well my friend has a revox b150, a good old integrated but nothing spectacular or particularly exotic
I have the feeling that ANY amp of reasonable quality can have similar results

The performance on the square test is similar to that of an amp instead of that of a speaker
I think that this text is exceptionally severe for ANY loudspeaker
Unfortunately very very uncommon
Surely as anything in real life these speakers have limits ( I think a limited max SPL with low distortion and also limited bandwidth)
But within these limits ... well I am here to get opinion

I will try to answer all of your extremely kind and valuable reply
Kind regards,

gino