Opinions on the meaning of driver 'speed'

[AllenB]

I first thought about this when listening to a 3" paper full range car speaker. My opinion at the time was that it sounded like it had a light cone. I liked this. It kind of sounded fast and detailed.

This was a midrange thing and that driver didn't have too much treble, but it didn't strictly need it either. That fact confuses my thoughts on the matter as I thought this had something to do with running the drivers out of band.

Could it be that when a driver reaches its upper limits and rolls off and is mechanically reactive, that this energy storage is what robs it of this quality of speed? I'm aware there are conflicting opinions on this.

The thing that threw me is the way this driver didn't have treble issues. Perhaps this full reange driver was designed to have a low Q bandwidth with better transient response near the top? It's falling power response would serve to hide this a little. Transient response is another controversial issue but again, maybe a matter of degree? How much?

It may then stand to reason that the electrical filter is just as responsible. Eg: If you cross near a woofers upper rolloff (a clean part), with reduced crossover action for a target LR4, it may be subjectively the same as a more or less full electrical LR4 implemented mid band?

On the other hand, an accurate speaker does not necessarily sound "fast".

Thoughts please?

[mdocod]

This may sound kind of strange, but I would characterize "fast" or "good transients" with speakers that have a more forward sound. In other words, speakers that do not "disappear" usually sound "fast" to me. The well thought out designs that "disappear" often sound a bit lazy and slow IMO.

So much subjectivity though I very much look forward to hear others responses.

[sreten]

Hi,

It may sound fast, but you'll soon get bored with the lack of bass and treble.

Quad ELS57's, over 50 years later, are still a reference standard for a
speaker that amongst other things sounds incredibly "quick" but subtle.

rgds, sreten.

[a.wayne]

Originally Posted by AllenB

I first thought about this when listening to a 3" paper full range car speaker. My opinion at the time was that it sounded like it had a light cone. I liked this. It kind of sounded fast and detailed.

This was a midrange thing and that driver didn't have too much treble, but it didn't strictly need it either. That fact confuses my thoughts on the matter as I thought this had something to do with running the drivers out of band.

Could it be that when a driver reaches its upper limits and rolls off and is mechanically reactive, that this energy storage is what robs it of this quality of speed? I'm aware there are conflicting opinions on this.

The thing that threw me is the way this driver didn't have treble issues. Perhaps this full reange driver was designed to have a low Q bandwidth with better transient response near the top? It's falling power response would serve to hide this a little. Transient response is another controversial issue but again, maybe a matter of degree? How much?

It may then stand to reason that the electrical filter is just as responsible. Eg: If you cross near a woofers upper rolloff (a clean part), with reduced crossover action for a target LR4, it may be subjectively the same as a more or less full electrical LR4 implemented mid band?

On the other hand, an accurate speaker does not necessarily sound "fast".

Thoughts please?

The speed u talk of is there with drivers with no x-overs , the
More x-over , the more u lose speed. X-overs should just be enuff to get the job done and no more, balance is important...

Ohh...

There is nothing subtle about a quad ESL 57, may I suggest upgrading ur amplifier ....

[AllenB]

Replies so far are suggesting bandwidth as a concern, assuming that electrical and mechanical rolloff create the same storage based effect. That could mean transient response, or rate of phase change, or the response itself. I notice this effect more often with small full range drivers. This could mean a number of things but possibly just because they are run out of band allowing this to show up? I've heard a set of very 'fast' sounding full range multi way speakers but they were most annoying to listen to.

a.wayne, I use an JLH amp, and I own a Quad 303 amp. Any suggestions?

[Pano]

A lack of bass is what I normally hear in speaker that are said to be "fast." But overall I think it's a lack of overhang, if that's the right term. There aren't any pronounced or long resonances.

Since resonance often lingers in the bass, perhaps a lack of bass also equals a lack of pronounced resonances?

[AllenB]

That did occur to me Pano. I guess I have doubts about my knowledge of bass due to the nature of the various bass issues. However technically, I believe, mechanical and electrical filters, room modes and even reflections can be seen as resonances. The subtleties are 'interesting'.

So I guess that still doesn't show whether a lack of bass or a lack of bass issues, is the root of that observation.

However, I may revisit my own crossover. It's been a few months LR is referred to as critically damped, but this has been debated lately. It seems that it tends to undershoot the 'leading edge'. Bessel seems to be popular. I read somewhere lately that Butterworth starts better, even if it ends a little worse.

[tinitus]

Originally Posted by AllenB

On the other hand, an accurate speaker does not necessarily sound "fast".

no, it needs the 'speed' to be able to sound slow(read relaxed)
some might call it dynamics
I would call it 'headroom'
and it can be dammed fast, and precise, when needed

but most music is really 'slow'
and thats the most difficult aspect
I mean, difficult to do correctly

but if a speaker sounds fast, its just because its stressed
consider it like a vinyl record turntable
running too fast, music sound thin and almost glassy, ipod like
running slower with correct speed, music sound much more right, and musical

but music at low or high SPL is not quite the same thing
takes different design/setup
so what could result in perfect speed or control might not be so at high SPL
just different priorities

[AllenB]

Originally Posted by tinitus

no, it needs the 'speed' to be able to sound slow(read relaxed)

[off topic] That is very insightful, tinitus. You remind me a little of my cousin. We are both keen aquarists. I like to balance my systems using chemical analysis. If I begin to talk testing with my cousin, he seems to already have the answers. He watches his fish, and can tell what's going on just by reading their attitudes.

and it can be dammed fast, and precise, when needed

but most music is really 'slow'

Hmmm. Yes I'd like a dollar for every time Ive sat and thought that my system was lacking, only to come across some one in a hundred passage of a recording and think " @*$%, it wasn't telling me it was capable of doing that".

but if a speaker sounds fast, its just because its stressed

Hmmm, perhaps. But how? I think a 'fast' sounding speaker sounds that way even at lower levels, so I wonder maybe we can dismiss the various 'overload' kinds of distortion and assume that leaves a resonance Q kind of stress?

but music at low or high SPL is not quite the same thing
takes different design/setup
so what could result in perfect speed or control might not be so at high SPL

I wonder about this. Speakers tend to have maximum reasonable listening volumes (I'm wavering on doing Pano's test thread over my thoughts on this max volume). When we design with well thought out drivers and when we cross well, a speaker can still be limited in max volume by things that sound worse as we turn them up, like diffraction, cabinet resonances and even thermal compression. So I wonder how much of what you say can be easily mixed up with these other issues.

[speedie]

allen do you feel that a vehicle is a good place for sonic listening
if i have misunderstood your post please dont be upset
i sort of thought that the car enviroment and audio content are harsh on quality