Does anyone else think compression drivers sound bad?

[DualTriode]

Hello All,

Drivers; cones or horns are electro-mechanical-acoustic devices. Electricity goes in and moving air, sound comes out. The driver is a transformer that changes electrical power to acoustic power.

Horns develop much higher asymmetrical (nonlinear) air pressures and velocities than cone drivers.

Voice coils in series have completely different impedance curves than voice coils in parallel. Put resistors in series and or in parallel with the voice coil and other unexpected thing will happen.

A not so simple L-Pad normally thought of as a driver level control changes series resistance and voice coil parallel resistance while just turning a knob on a pot. The impedance curve also changes when you are turning the knob on the L-Pad. Q changes with output level. One more reason for active line level crossovers if you are counting.

It is instructive to put a few drivers on the bench and measure them.

Thanks DT

 

[phase_accurate]

The driver is a transformer that changes electrical power to acoustic power.

Just a small thing: I would use the term transducer in this case,.

Regards

Charles

 

[AllenB]

Then there's the difference between non-linear impedance and non linear impedance..

 

[N101N]

An efficient system is a poorly damped system that develops a rapidly rising distortion with increasing energy level. There do not exist any linear physical relationships.

 

[Schmitz77]

All those poorly designed, efficient LOUDspeakers must do something right in my ears.

 

[phase_accurate]

One reason is that they are LOUD speakers and not faint-whisperers (with which one could live) or loud-screamers. They remain relaxed with authority up to higher SPLs than the faint-whisperers or loud-screamers.

Regards

Charles

Edit: In German there is an expression called "Bruellwuerfel" for the small and loud category. Maybe someone knows a good English equivalent for that.

 

[multitask]

i even think this $65 combo sounds fine (with some EQ) a bit metal character to the selenium but no pressure on the ears even at very loud levels.

 

[DualTriode]

Just a small thing: I would use the term transducer in this case,.

Regards

Charles

For sure a driver is a transducer.

I used transformer to make a point about modifying impedance, Impedance was what we were speaking of.

Search this attached document for horn as a transformer. https://www.grc.com/acoustics/an-introduction-to-horn-theory.pdf

@camplo you will recognize the Figures as the ones you posted.

Thanks DT

 

[N101N]

I would like to add that distortion does not automatically mean bad sounding. Distortions are not equally objectionable.

 

[camplo]

DT - the graph I posted, I took from that document =)

An efficient system is a poorly damped system that develops a rapidly rising distortion with increasing energy level. There do not exist any linear physical relationships.

if I take my high sensitivity drivers and dampen them well...I still have the benefits of a high sensitivity driver and the benefits of a well damped system....is this system efficient?

 

[celef]

All those poorly designed, efficient LOUDspeakers must do something right in my ears.


[pic]

interesting damping in that box, that sheet of mineral wool may vibrate by the sound pressure and have a nonlinear damping, it should have been braced

 

[Jonasz]

An efficient system is a poorly damped system that develops a rapidly rising distortion with increasing energy level. There do not exist any linear physical relationships.

Are you saying an efficient system sucks?

 

[N101N]

The result is reduced sensitivity. Efficiency, sensitivity and amplification factor mean the same thing.

 

[N101N]

I am saying that an efficient system exhibits high distortion.

 

[AllenB]

In what way is it poorly damped?

By what mechanism does this distortion appear with increasing level?

 

[N101N]

I am struggling to say this clearly and concisely. High efficiency means low resistance, high impedance, small mass, high velocity, high amplitude, low excitation energy and being closer to resonance. A small mass is hard to control, resulting in inconsistent motion. An increase in amplitude means a decrease in mass (by Coulomb`s law). Mass, capacitance, current and weight are equivalent.

 

[Schmitz77]

Gray, dear friend, is all theory and green of life's golden tree.
Faust 1, Studierzimmer. (Mephistopheles)


But with those overdamped and closed miniature, low efficiency speakers of today modern Hifi has established.
It was a collaboration of having enough power input from the ampside and low eff. speakers.

 

[AllenB]

N101N, I wouldn't blanket agree with the mass relationship where it pertains to practical speakers. Lower mass can mean higher efficiency as you suggest, but other factors involved mean that it is possible to have this same relationship in what we'd call a low efficiency speaker. This would obviate your concern of the amount of cone control being a general problem with high efficiency, if that even applies... and what do you say about the efficiency of the motor bringing more relative control in any case?

What you are calling damping, if I understand correctly, others may be calling bandwidth. Bandwidth and efficiency generally trade against each other as you suggest, but where a flat response is obtained, where is the damping issue to be found?

high velocity, high amplitude

I'd disagree with this. Take two speakers with the same sized cones, each producing a sine wave well within their pistonic range, and measured to be the same pressure.. even though one is high efficiency and one is low efficiency. The cones are moving the same amount.

 

[schiirrn]

+1

 

[DualTriode]

In what way is it poorly damped?

By what mechanism does this distortion appear with increasing level?

It is not so much damping or not damping at all it is compression plus high velocity air in the phasing plug and throat of the horn.

See the attached JBL technote for a discussion of the compression caused distortion.

Thanks DT