Fast midrange driver

diyiggy

Member
2019-01-16 12:22 am
sorry for my english which is not acurate and often not clear enough, but I writted quite the opposite.

Also I talked about the weigth/motor ratio in relation to what Planet10 writted just before. I don't think it's usefull for the subject here about speed, so again I am not contributing to the myth. I try to windowing the subject for the op or for some that are staying about the myth of speed matching between the drivers.

I'm sorry to not be clearer, but please if I writted some mistakes, I'm ok for corrections, I'm here to know more as well and few times ago I could have asked the same question than the op :).
In the meantime, I think I tried to show where the speed could be (only) involved by comparing a little driver to a bigger to reach a certain spl at iso frequency if you re read carrefuly (because of my english, not because this is the information of the century ). to resume, it's not because a driver could be faster than another at the same task than the listener will perceive faster sound. I writted before in the thread, than drivers are fast enough for their job at flat power response.
 
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I think OP need to define “fast” and “speed” , what kind of sound he is expecting from these terms.

In theory the perfect driver would sounds true to the signal source and have very minimal signal decay , yet this might not be what OP expecting.
For example ScottG post seems to think “fast” as dynamic sounding, others would say electrostat or diamond membrane sounds fast.
 

Dennnic

Member
2021-01-23 8:15 am
That's mostly the definition of what I was trying to reffer to - a driver that has good transient response / short decay rate on a waterfall graph.
I hoped that would make for a realistic sound reproduction. However, I haven't yet got to the bottom of that theory.

I did make some progress in my DIY system, I opted for a small wideband (4 inch) driver, with a low crossover point (~280 Hz) to two 12 inch woofers.
All of those drivers are made by the same manufacturer with the same paper cone material (relatively light for their size) and hefty oversized magnets. I went with an open baffle configuration. Haven't finished the crossover yet, so I can't comment on the sound.
 
That's mostly the definition of what I was trying to reffer to - a driver that has good transient response / short decay rate on a waterfall graph.
I hoped that would make for a realistic sound reproduction. However, I haven't yet got to the bottom of that theory.

In my experience paper cone dynamic driver is not gonna deliver the performance for short decay

Surface noise of the cone nature is the limiting factor, also how the damping or reduction of it is achieved. ( hence difference in sound from cone material composition)

Best good damped yet stiff pistonic cone dynamic driver midrange I have heard (when applied correctly) is less talked about here, Morel SCM634 (there is also TSCW634 different voice coil former material).

Unless the midrange cone is made of diamond, then planar , ribbon and electrostat would beat all dynamic cone driver audible decay wise.

However another factor I noticed in midrange frequency sound reproduction, the front wave loading ( baffle, horn, cone shape and size ), and the dispersion characteristic is quite important factor in reproducing midrange frequency, wider off axis response and no horn loading tend to deliver less audible artefact, in such way that 2”-3” soft dome can sound comparably clean or faster than planar, part of it is from the wide dispersion ( interaction with room reflection and and sound perceived by two ear) and smoother less jarring on and off axis transition over wide range of frequency.

One thing about lower efficiency driver despite having good cone damping is the demand almost all amplifier topology to deliver good clean signal audibly, mostly the power supply noise and rejection of it (PSSR) is the culprit here. This is a tradeoff, better speaker and better amp works together better.
 

adason

Member
Paid Member
2004-11-10 8:31 pm
Maryland
That's mostly the definition of what I was trying to reffer to - a driver that has good transient response / short decay rate on a waterfall graph.
I hoped that would make for a realistic sound reproduction. However, I haven't yet got to the bottom of that theory.

I did make some progress in my DIY system, I opted for a small wideband (4 inch) driver, with a low crossover point (~280 Hz) to two 12 inch woofers.
All of those drivers are made by the same manufacturer with the same paper cone material (relatively light for their size) and hefty oversized magnets. I went with an open baffle configuration. Haven't finished the crossover yet, so I can't comment on the sound.
So you actually were looking for fullrange? Not the midrange?
That is quite missleading.
 
Hartono, maybe you should share your wisdom and insights of paper cones and their shortcomings with Lars Riisbo, the Purify designer...
, we dont use much paper cone tweeter for this reason I think many can understand that.


We don’t use much paper cone tweeter.

There are many papercone driver producer who are knowledgeable enough on cone material sonics.
 
There are material properties, such as e.e Youngs Modulus, Poisson's Ratio etc, but not "sonics". The latter is not a (design) parameter, but a vague non-specific description of "how it sounds".
Ok I understand there are many ways to describe and present ideas.

and I prefer to discuss “how it sounds” not specific number in some of the parameter which the number often difficult or not useful to convey the sound we hear.

There is also matter of micro geometry of the cone internal material, similar sounding number could both sound quite different or not much difference.
 
I could only wade through the first page as so mush totally uninformed comments, interleaved with valid.
'Fast" is a BS term. Anyone using it does not know what they are talking about.

We can plot output against frequency don't need "tonal balance" gollbity gook speak.
We can plot impedance against frequency
We can plot phase against frequency
We can plot harmonic distortion against frequency and level
We can measure polar plots shown the energy produced by various frequencies 3 dimensionally
What some might be referring to is a driver with well behaved decay as measured in a CSD ( Cumulative Spectral Display) plot. In other words, when you stop giving it drive, how well does it stop moving? Easier said than done. Remember, all speakers are a spring loaded mass.
We can use laser interferometry to see what mechanisms are causing teeter-totter, bell mode, breakup and other deformation issues.
We can use simulation of the motor to determine it's linearity

Ability to reproduce one frequency while repruning a large excursion of another is referred to as "Doppler Distortion. It is most often an issue with woofers. How to measure, now that might be a tick. Multi-tone distortion, but contriving the signal would take some work. I do not believe there are any standards as they would have to relate to the specific driver.

Unfortunately, with drivers, the only test I know is reliable is "Try it" Basically all drivers are soooo bad, it comes largely down to your preference and how you may use it. Some pretty cheap drivers used well can be great, and I have head my share of great drivers used terribly. XT-25 crossed at 2K ARRGGG!

FWIW, PS sells good amps, but pushes truckloads of snake oil. Consider their news letter entertainment.
 

mark100

Member
Paid Member
2010-12-24 5:49 pm
When a system is dynamically competent, it stops sounding like anything.. you wouldn't be giving it labels like 'fast'.
+1

"Fast" does not even apply to a driver.....any driver.
It does apply to a complete low-to-high speaker system......
and for heaven's sake, all "fast" means is flat full-range response, with flat phase being the icing on the cake.