What makes different speakers sound ... different?

[sreten]

IMO to be serious for a moment :

1) Poor general design
2) Poor crossover design
3) Drivers used (though good 1&2 cannot fix bad 3)
4) Box type, tuning, size, etc
5) Box construction quality
6) Suitability for purpose

sreten.

[pinkmouse]

And , of course, the taste of the designer...

[Cal Weldon]

Originally posted by cuallito
What in a speaker affects it's sound the most?

Hi cuallito,

I think you might want to narrow your question down a little bit so we have a chance to give you a serious answer.

What is it you would like to know about the holy loudspeaker?

Cal

[till]

most important for the sound quality is the quality and quantity if wine you drink while listening.

If you do a search you will find some postings by well known and respected persons in this board who will confirm this.

The principle is:

good wine, a bit: sound better
a bit more: sound a bit much better
and more and more and more, sound is outstanding, you are high, crank up volume.
much more: you don´t find the player to change CD.

bad wine:
a bit: does it still sound good?
bit more: crank up the volume.
more: it does sound a little - metallic? distorted? and not load enough.
more: fuzzy, somehow
more: head aches
too much: wake up next morning, clean up the mess.

[hunter audio]

hi


a driver cannot be defined by ,

to consider its t/s parameters , never actually suggests how it will play

or the materials it may be constructed with , ofcourse if it was to be used by the police force - kevlar is very important

but when it is to ultimately convert source to analougus sound , what are on line is its realism , accuracy , depth , tone / timbre , nature etc in hi fi

in pro audio - directivity , effective spl , accuracy , decay etc

it cannot be defined by a mechanical formula

what has all this got to do with diy ?

when one has to choose a drive unit or units for ones amp / speaker enclosure in mind etc

what are the factors worth considering ?

considering a purchase of a loudspeaker unit

ts parameters defines this unit mechanically , through these mechanical parameters one can proceed to use / utilise the unit to its best , including efficiency , and is of utmost importance to its enclosure design enclosure

but one has also paid for the materials used in the construction of the drive unit ,

this will decide its longetivity , compression at peak power , overall accuracy - not to mention the tonal quality or the nature of sound produced

where am i heading , - the internal volume of a cone may be same as that made of ordinary hard pressed paper or for eg a kevlar woofer

1 set of compliance figures can be easily duplicated between

a rubber surround cone / and a foam surround cone

all the manufacturer needs to do is control the hardness factor of the rubber surround material (ie the rubber)
and
the density of the foam material _ of the foam surround

with this surround material differance the sound quality of both the drive units will be entirely different

- along with the materials used the construction process is of importance

so is the x- max the voice coil inductance , the cooling efficiency

distortion - can be reduced by a symmetrical field magnet structure , shorting rings for eddys , shorting rings built into the coil to limit the coil from leaving the magnetic gap during extreme excursions

these important issues relating the drive unit is not reflected very much in the t/s matters

where am i going ?

i can copy a standard 100 $s subwoofer unit' s t/s parameter using

ordinary components for eg a pressed paper instead of a non press one , same coil dia , wire winding etc but with a poor insulation

and it will never play , last , sound as the original 100 $ s one

this is of utmost importance to diy constructors , along with t/s parameters

Reverting to important issues governing diy and speaker design

1 . The speaker matching with the amplifier ,

I can provide a double magnet (155 to 230 mm) subwoofer in a lambada extended pole underhung sfg topology magnet structure with a kapton voice coil with imported aluminum wire voice coil lengths in excess of 60 mm with a xmax of 25 mm at 4 ohms , a imported non-press paper rubber surround cone (which totally absorbs all mid + hi frequency due to the cone design)
and
if the user constructs the most powerful IC amp it will not match
infact it won’t match a 150 w rms transistorized design using latest Toshiba ets transistors
the reason – the magnet structure is over damped
now if it was the crescendo mosfet amp then we are going somewhere ,

Two

the type of the transducer , its power handling , has the voice coil size been increased blindly to increase power handling without magnetic efficiency and x – max in mind ?

the type of cone used , pressed paper , semi press paper , non press paper , felted composite , reinforced ets ( this decides how the speaker will sound )

the motor structure , sfg (symmetrical field geometry magnet structure) , for full range and pro drivers if there are eddy current shorting rings , other shorting rings employed to extend frequency response , linearise impedance , improve transience

the vc material and wire , the vc inductance – 2 layer , 4 layer , dual vc type etc

the suspension system and compliance
surround material , eg rubber then type natural or synthetic ets , the extent of the roll of the surround and its match with the spiders

the construction – at the end all parts of a speaker is held together by adhesives , the quality of adhesives used / and the process of manufacturing , for eg if I repair a toy with a epoxy hardener type adhesive and do not allow for the correct drying time …

at the end all manufacturers are increasing production speeds

suranjan

transducer design engineer

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then a good driver ?


hi

this statement can be said as correct that :

a power rating given to a driver , means that at all input levels of the driver rating within its specified limit , the driver :

1 ) should perform within the rating in long term use , robustness

2) should perform within very acceptable limits of distortion

3) and should show a certain limit of linearity in relation with the , actual accoustic power output increase to the input power supplied from the amps

without compression

the distortion is now adays mostly the deciding factor of the power rating including long term use

Here it needs to be devided in two sections


FIRST SECTION

in a broad context

distortion / you will find some speakers distorting _ much before the voice coil actually burns out

for eg - considering a driver in which this takes place :

a driver or if they are pro audio or drivers with simple pole vent cooling with the coils set in a tight magnetic gap - the coil can be on a paper former , oridinary wires used in the vc s

the vc s temperature will not rise easily normally 60 deg max , at this time it will distort

then this distortion is not from the vc temperature

(though in most books vc temp is one of the main source of distortion , why ? read on ....)

there are 3 basic types of non linearity in a transducer , these generate distortion , due to this distortion the voice coil heats up / at this moment no amount of cooling can help ,

the distortion effect from driver non linearities are such that it may lead to vc temp rise exponentially leading to vc burn out

the non linearities are

1. non linearity in the suspension mechanism

2. non linearity in the motor sturucture

3. non linearity caused when a coil moves in a permanent magnet motor structure (this is bound to happen even if the above 2 non linearities are addressed well )

to check for these non linearities while purchasing drivers

1. suspension non linearity

for the x - max of the driver you would like to purchase (or the one specified by the manufacturer) meaning you either know the x-max or have one in mind , then :

step a
push the driver cone downwards by that amount , it should go down linearly (the stiffness of the suspension increasing linearly) to the amount of the x-max

step b
pull the cone upwards towards you from beneath and it should come up to the specified x-max , again stiffness increasing linearly

if this does not take place the driver will distort -

unless the transducer manufacturer identifies specifically that such a non - linearity has been addressed , by making suitable compensations in the vc itself

2. motorstructure non linearity

fringe fields exists at the magnetic gap - the motor structure should be - sfg a symmetrical field geometry _ topology

therefore while purchasing a driver look if the motorstructure is - sfg or not

since expenses goes up in a sfg structure it will be specifically mentioned mentioned by the driver manufacturer , to inform customers


3. Non linearity caused when a coil moves in a permanent magnet motor structure

explaining this nature of non linearity is complex , anyone interested can see the sections on shorting rings in my thread

what is important

is that : -
has this been addressed by the transducer manufacturer

it is addressed by shorting rings placed in the motorstructure

since this too involves expence , and a considerable slow down in the manufacturing process this too will be specified by the driver manufacturer , to inform customers

-

the above are the main sources of distortion that determines the safe operating power of a driver , and are not the only sources of driver distortion (other sources of distortion are eddys , bottoming to name a few)

due to such complex stuff good driver manufacturers all over the world can be counted on finger tips

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SECOND SECTION

in good drivers context

good drivers are in which all the above criterias have been addressed

then the rise in vc temperature over long time use / the cooling efficiency comes in , and mostly all speaker failures of reputated manufacturers result from vc burn out (as mentioned by Navin)

mostly these limits are tested thoroughly and drivers tested to distruction and safe regions specified

Suranjan Das Gupta

Transducer Design Engineer

[hunter audio]

i have found driver malfunction due to negligence of owners to go in for a service contract when pro audio drivers are used eg - movie halls , discs

in home audio , sources of reputated driver burn outs are :

a)
amp malfunction and dc component generation in the drive signal or signal clipping

speacially when high power speakers are used by under powered amps , many people do not even consider that a 35 w amp can damage a 100 w speaker system _ plain simple signal clipping can distroy well made drivers

if you have an under powered amp please ask a sound engineer to determine the clipping levels of your amp and restrict from running at clipping levels (in high end audio amps from manufacturers like Nad and onwards this is built in as standard , in the circuitry , therefore the prices)

b)
or the suspension parts have outlived _ may be the owner !

Suranjan Das Gupta

Transducer Design Engineer

[Cal Weldon]

Hi Suranjan,

What a novel.
I wonder if the original poster has any idea of what you just wrote?

Thanks for the reading,

Cal