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Importance of woofer size in sound quality

Wharfedale EVO4.4 Speaker

Muthusami S

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Dear Friends,

Looking forward to your view points about the significance of woofer size in floorstanders. As suggested by my friend, I bought floorstanders with 12" woofers. But I found most of the popular brands use drivers max. of 10" and some brands use 2 bass drivers of 6.5" per channel. Also some brands use only one driver (instead of woofer, mid range, and tweeter) in big floorstanders. Some home theater box units claim 300W RMS ouput using 4" woofers!

Using higher size drivers, will increase the sound quality? For example, for 150W RMS output, if 12" driver is used instead of 10", will the sound quality improve? Or the sound quality purely depends on the quality of driver material used, crossover, and how the cabinet is designed, irrespective of the driver size.

Please share your views.

Regards,
Muthusami. S
 

hifi

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Looking forward to your view points about the significance of woofer size in floorstanders. As suggested by my friend, I bought floorstanders with 12" woofers.
Can you specify what is your speaker make and model?


Using higher size drivers, will increase the sound quality? For example, for 150W RMS output, if 12" driver is used instead of 10", will the sound quality improve? Or the sound quality purely depends on the quality of driver material used, crossover, and how the cabinet is designed, irrespective of the driver size.

BY increasing the driver size, you can increase the power handling but it may not directly contribute to the sound quality. It may improve the bass frequency handling.

As far as I understand, the size of the speaker driver (the diameter) depends on the frequency range which it is supposed to handle. The higher the dia, the lower the frequency.

The quality of the speaker depends on many factors including

- Speaker driver characteristics
- Cabinet design
- Crossover design

I hope we can have gyaan from our gurus in this forum

Regards

Pradeep
 

neo

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It has to be a whole package by all means.

I'm a big believer in bigger drivers esp fro hifi. As after hearing 12" & 15" drivers i find it hard to like my music on spk with smaller drivers .
Sadly majority new designs max out with 6.5" drivers due to a boom in hometheatre,WAF, small houses in most major cities around the world & of course smaller drivers are chearper to build.
For Home theatre one can still live with smaller drivers.
Cheers.
 

Muthusami S

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Thank you very much for sharing your points. I use Craftel floorstanders, a product of Audiocraft, Chennai.

Regards,
Muthusami. S

Can you specify what is your speaker make and model?




BY increasing the driver size, you can increase the power handling but it may not directly contribute to the sound quality. It may improve the bass frequency handling.

As far as I understand, the size of the speaker driver (the diameter) depends on the frequency range which it is supposed to handle. The higher the dia, the lower the frequency.

The quality of the speaker depends on many factors including

- Speaker driver characteristics
- Cabinet design
- Crossover design

I hope we can have gyaan from our gurus in this forum

Regards

Pradeep
 

soundsgreat

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Hi,

This is most controversial and misconceptualized fact in the Audio !

So both of you are right to an extent !!

First off,The driver dia will only matter if all other aspects are not taken into account like box design,crossover type & design,material of the box,damping etc etc ! if everything is taken into account then you don't need a large size driver to reproduce the sound properly ! even the bass !

Power Handling is also the same ! lots of misconception in the people's mind about this !

There's no need for a high powered system to reproduce accurate and quality sound !!

Another Important thing when it comes to speakers are its sensitivity ! how sensitive the speaker are depends on how much power it will take to reproduce X dB sound level ! in other words if the speaker is more sensitive then it takes less power to reproduce the X dB sound then an less sensitive speaker !

BUT this does not mean that less sensitive speakers are bad sounding ! its just to be taken as reference !!

So this is just a very basic and brief info into the subject ! coz if I have to explain in detail then it'll be atleast 2 pages and Am sure you folks will get bored !! so won't do it !!

Instead,if any specific quires are there,then please do ask so that we can answer !!

Just one small Ex is my own DIY towers ! for the folks who doesn't know bout this can follow my signature to findout !! others who know the thing and have heard will be in better position to comment on the sound part (both quantity and quality)

Regards.
 

Muthusami S

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Soundsgret,

Nice explanation. Thanks a lot.

Regards,
Muthusami. S

Hi,

This is most controversial and misconceptualized fact in the Audio !

So both of you are right to an extent !!

First off,The driver dia will only matter if all other aspects are not taken into account like box design,crossover type & design,material of the box,damping etc etc ! if everything is taken into account then you don't need a large size driver to reproduce the sound properly ! even the bass !

Power Handling is also the same ! lots of misconception in the people's mind about this !

There's no need for a high powered system to reproduce accurate and quality sound !!

Another Important thing when it comes to speakers are its sensitivity ! how sensitive the speaker are depends on how much power it will take to reproduce X dB sound level ! in other words if the speaker is more sensitive then it takes less power to reproduce the X dB sound then an less sensitive speaker !

BUT this does not mean that less sensitive speakers are bad sounding ! its just to be taken as reference !!

So this is just a very basic and brief info into the subject ! coz if I have to explain in detail then it'll be atleast 2 pages and Am sure you folks will get bored !! so won't do it !!

Instead,if any specific quires are there,then please do ask so that we can answer !!

Just one small Ex is my own DIY towers ! for the folks who doesn't know bout this can follow my signature to findout !! others who know the thing and have heard will be in better position to comment on the sound part (both quantity and quality)

Regards.
 

magnet

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The quality of woofer doesn't depend on the size ... The things that you shoud look for in a woofer is its cabinet design.. For example take BG corp's R-88 Sub it outputs 1000 W RMS from two 8'' drivers ... :D
 
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Anil kumar

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People use inches and watts method to evaluate the performance of a subwoofer. They assume that the bigger the driver size better the subwoofer. It's a bad assumption. These two facts tell us absolutely nothing about how loud the subwoofer will play, or how deep it goes, or how accurate it sounds. One could at least assume that the sub with the largest amplifier would play the loudest. How loud a system plays is a function of the available clean power and the efficiency of the driver & cabinet system. Efficiency tells us how much of the input power gets used to make the sound. A speaker system with an efficiency rating of 90dB would sound audibly louder than another system with a rating of 87dB doubling of power is3dB has greater sound output, a 90dB efficient system driven by 50 Watts would play just as loud as an 87dB efficient system driven by a 100 Watt amplifier. Similarly a 90dB efficient system would play 3 dB louder than an 87dB efficient system if both are driven by the same 100 Watt amplifier, woofer size is not a good predictor of efficiency. A woofer needs to have solid output down to 25Hz to qualify as a genuine sub-woofer that makes movies and music sound like life.












.
 

Muthusami S

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Oh! That's great. Thanks for the information. So if the same cabinet design, same cross over, and same driver material used with 12" or 15" woofers, will the output quality remain the same?

The quality of woofer doesn't depend on the size ... The things that you shoud look for in a woofer is its cabinet design.. For example take BG corp's R-88 Sub it outputs 1000 W RMS from two 8'' drivers ... :D
 

Muthusami S

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People use inches and watts method to evaluate the performance of a subwoofer. They assume that the bigger the driver size better the subwoofer. It's a bad assumption. These two facts tell us absolutely nothing about how loud the subwoofer will play, or how deep it goes, or how accurate it sounds. One could at least assume that the sub with the largest amplifier would play the loudest. How loud a system plays is a function of the available clean power and the efficiency of the driver & cabinet system. Efficiency tells us how much of the input power gets used to make the sound. A speaker system with an efficiency rating of 90dB would sound audibly louder than another system with a rating of 87dB doubling of power is3dB has greater sound output, a 90dB efficient system driven by 50 Watts would play just as loud as an 87dB efficient system driven by a 100 Watt amplifier. Similarly a 90dB efficient system would play 3 dB louder than an 87dB efficient system if both are driven by the same 100 Watt amplifier, woofer size is not a good predictor of efficiency. A woofer needs to have solid output down to 25Hz to qualify as a genuine sub-woofer that makes movies and music sound like life.
.

Anil,

Thanks a lot for the information. I think you hit the nail on the head about the size. So I understand that the size doesn't matter but the other factors.

Regards,
Muthusami. S
 

SAMUEL

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Dear Friends,

Looking forward to your view points about the significance of woofer size in floorstanders. As suggested by my friend, I bought floorstanders with 12" woofers. But I found most of the popular brands use drivers max. of 10" and some brands use 2 bass drivers of 6.5" per channel. Also some brands use only one driver (instead of woofer, mid range, and tweeter) in big floorstanders. Some home theater box units claim 300W RMS ouput using 4" woofers!

Using higher size drivers, will increase the sound quality? For example, for 150W RMS output, if 12" driver is used instead of 10", will the sound quality improve? Or the sound quality purely depends on the quality of driver material used, crossover, and how the cabinet is designed, irrespective of the driver size.

Please share your views.

Regards,
Muthusami. S


Hi Mr.Muthu,
I'll try to answer your questions in parts.
First , as you know the human hearing range is 20Hz to 20Khz.
Less than 20 Hz is Infrasonic & greater than 20 Khz is Supersonic & Ultrasonic(faster than speed of sound).
The speaker is a transducer which converts electrical energy into Mechanical energy, which in turn moves the air.
Now a speaker with a bigger diameter will move more air compared to a smaller one.
But here's the catch...a larger driver will struggle to match the speed of sudden Transients(sudden changes in volume of different music-ex snare drum).Why?:confused:
Imagine you have a hand fan(in tamil Visree-members kindly excuse).A smaller fan will be easier to use but a larger fan will strain your hands because of the pressure created in the fan. A similar thing happens in the Cone surface of the woofer, more power will be needed to push air around.
Now you know why subwoofers are big .Purists say anything below 10" is not a subwoofer.

Now for smaller cone speakers.1st they will be lighter. smaller cone will be faster.so Transients are easily captured.And the fastest of these will be the Tweeters which will operate near & above supersonic levels.

You also might have noticed most small coned speaker around 6.5in size will be a Bass Reflex type.This is done to reinforce the bass response. The natural lo-frequency response of a small cone speaker will be higher than a bigger woofer. For Ex 6.5in woofer Fs will be say 45Hz whereas a 12" woofer will have a Fs of 23 to 27Hz approx.
In order to acheive good low frequency sound manufacturers tune the port(Bass-Reflex) to a frequency sligtly closer(sometimes lower) to the Natural Fs of the speaker.
Box design , Volume of the box, Damping are other important factors that will be considered...

But Loudspeaker Technology has come a long way that a small coned speaker will & can Outperform an Larger coned speaker.

Since living space is a premium now-a-days so small slender Towers or Bookshelf speakers are considered.Home theatres are the In Thing now and movies have the most extreme Transients ,necessitating a faster midrange and a Slamming low end.(Ex Sat-Sub Combo).

But One thing is for sure Nothing compares to Cubic Capacity, same way the size of Speaker. A Tower Speaker is a Tower Speaker.
Bigger Better.(Conditions Apply).

Klipsch LaScala 15" Drivers.
Klipsch Horn -15"
JBL Synthesis with 18" Subwoofer
JBL K2 Series.

These are speakers I can Only Read and Dream about.:rolleyes:

Smaller speakers(Relative to size) are cost effective , user friendly and deliver the best of both worlds...IMO.
A small Sat-Sub combo can never give the Large Scale presentation of a good Floorstanding speaker.

Its 1:15am so I'm a bit sleepy, kindly excuse if this is an overkill.And thank you for your patience.

There is just so many things i wanna share but ....;)

With Best Regards
SAM.:cool:

Size Does Matters.
.
 

arj

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Size Does Matters.
.


I would tend to agree with this. there is only so much air an 8" could move
large woofer size produce more SPL. although this has to be looked along with Room size.

A problem which comes up with large woofers is their Speed. many are know to be "Slower in Bass" and also cause distortion unless the material used in the cone is Rigid enough and once the rigidity increases so does the need for more power.so if you need pure SPL you need to have large drivers (Although these days the LOng throw drivers seem to be able to do quite a lot as well)

But again if you check out Wilson Audios THOR with 2 15" drivers, 200 KG and 5 feet tall ! They seem to have overcome the sloweness..although at a cost


but moment you talk about music another factor comes into play and that is the "Tunefulness " of the bass .
That is where the design come into picture. Typically there are 2 kinds of subwoofer designs.
Sealed Box: Known to be more tuneful bass but does not go down very low and very rapidly falls from ten 3dB to 10dB points hencethe depth will not be there (also for sealed box the depth Vs power requirements are exponential..so much to the extent that i know no one makes sealed boxes above 10"..and most of them are at 8")
Ported: the jury is still out on the sound quality but a well designed ported ia almost as good as a sealed box in Sound quality and with far less power requirements and more extension. but they are usually not "Fast enough"

i personally prefer sealed box speakers and a sub as most of the affordable ported enclosures are not good enough..

most music today has its fundamentals at around 35-40 Hz and harmonics extending below. so as long as your speaker system hit around 30 Hz albeit at 10dB you should enjoy your music.


these days with better driver design and long throw driver array drivers are present in subwoofers..

the Martin Logan subwoofers are an interesting design with 3 drivers at a pphase difference if 120 deg and 8" woofers. apparently they do a great job of musicality as well as SPLs. never heard them though !


so ig guess size does matter,,but there acn be compromises made via design with smaller drivers. But in the end the question is does your room need it ? :)
 
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Muthusami S

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Hi Samuel,

Very well written. Thanks a lot for your time in replying to my query at late night!

Regards,
Muthusami. S

Hi Mr.Muthu,
I'll try to answer your questions in parts.
First , as you know the human hearing range is 20Hz to 20Khz.
Less than 20 Hz is Infrasonic & greater than 20 Khz is Supersonic & Ultrasonic(faster than speed of sound).
The speaker is a transducer which converts electrical energy into Mechanical energy, which in turn moves the air.
Now a speaker with a bigger diameter will move more air compared to a smaller one.
But here's the catch...a larger driver will struggle to match the speed of sudden Transients(sudden changes in volume of different music-ex snare drum).Why?:confused:
Imagine you have a hand fan(in tamil Visree-members kindly excuse).A smaller fan will be easier to use but a larger fan will strain your hands because of the pressure created in the fan. A similar thing happens in the Cone surface of the woofer, more power will be needed to push air around.
Now you know why subwoofers are big .Purists say anything below 10" is not a subwoofer.

Now for smaller cone speakers.1st they will be lighter. smaller cone will be faster.so Transients are easily captured.And the fastest of these will be the Tweeters which will operate near & above supersonic levels.

You also might have noticed most small coned speaker around 6.5in size will be a Bass Reflex type.This is done to reinforce the bass response. The natural lo-frequency response of a small cone speaker will be higher than a bigger woofer. For Ex 6.5in woofer Fs will be say 45Hz whereas a 12" woofer will have a Fs of 23 to 27Hz approx.
In order to acheive good low frequency sound manufacturers tune the port(Bass-Reflex) to a frequency sligtly closer(sometimes lower) to the Natural Fs of the speaker.
Box design , Volume of the box, Damping are other important factors that will be considered...

But Loudspeaker Technology has come a long way that a small coned speaker will & can Outperform an Larger coned speaker.

Since living space is a premium now-a-days so small slender Towers or Bookshelf speakers are considered.Home theatres are the In Thing now and movies have the most extreme Transients ,necessitating a faster midrange and a Slamming low end.(Ex Sat-Sub Combo).

But One thing is for sure Nothing compares to Cubic Capacity, same way the size of Speaker. A Tower Speaker is a Tower Speaker.
Bigger Better.(Conditions Apply).

Klipsch LaScala 15" Drivers.
Klipsch Horn -15"
JBL Synthesis with 18" Subwoofer
JBL K2 Series.

These are speakers I can Only Read and Dream about.:rolleyes:

Smaller speakers(Relative to size) are cost effective , user friendly and deliver the best of both worlds...IMO.
A small Sat-Sub combo can never give the Large Scale presentation of a good Floorstanding speaker.

Its 1:15am so I'm a bit sleepy, kindly excuse if this is an overkill.And thank you for your patience.

There is just so many things i wanna share but ....;)

With Best Regards
SAM.:cool:

Size Does Matters.
.
 

magnet

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Size doesn't matter cos I own a designing firm in that I've installed R-88 Sub which outperforms my PSW1000 which is at home..Also guys acoustics play an important role.. I even kept the psw 1000 in the same place where I've installed R-88 but still R-88 rocks...Its small and it out performs psw 1000 ...:)
 

suniil

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:rolleyes: does it *really* matter? Cabinet size or Driver size? I guess OP asked just about the driver!!

A large well designed driver will definitely have the motor force to deal with the larger piston, plus it will move less for the same sound pressure levels which is a clear advantage. If large driver moves 5mm and the little one 15mm, which one will have more distortion?

Size doesn't matter cos
 

flanker.r

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ok guys been following this thread. Too much speculation going on.

There are flaws being made with regard to fundamental aspects. First of all ultrasonic and infrasonic refers relative velocity of a body with relation to speed of sound at MSL (or given conditions). This is also called Mach no. So in one way we can say that speed of sound is mach 1. Speed of sound does not depend on frequency. So you will have a 20 hz wave and a 20k hz wave traveling with same velocity. That??s Point not 1. We don??t call this infrasonic, ultra or supersonic. We simply refer to them as lows, mids and highs (ya it does'nt sound as fancy as 'supersonic' but it is more audiophilic. what say?).

2nd point is bass reflex ports are not provided to ??reinforce?? bass response although that is the perceived effect. Any driver has to be mounted in a minimum enclosure volume called the ??compliance volume??. This is the behavior of driver when it is in free space radiation in an infinite baffle. Compliance volume is given by manufacturer of driver during design and testing. If we cant get an enclosure that??s close or greater than the compliance volume we resort to ??ports?? to trick the driver into thinking it is in a larger enclosure (ya , this way we may tune frequencies that need to be emphasized with port area). We can get a ported system to perform like a sealed and vice-versa. It is impossible to find out if a ported or a sealed system is playing in a blind test

3rd point is that no small speaker with any amount of gimmickry/technology can outperform a bigger driver. If it does, it means the bigger driver was badly designed. It is not the strength of a small driver. In similar quality, construction, material selection and design, bigger driver will outperform a smaller one (with regard to low frequency extension)

Magnet is right when he says ??A large well designed driver will definitely have the motor force to deal with the larger piston, plus it will move less for the same sound pressure levels which is a clear advantage??

As to the question he has posed this is my answer. If the large driver has an Xmax (max cone excursion) of 3 mm and we move it 5 mm it will distort. If the small driver has a cone excursion of say 18 mm and we move it only 15 mm if will not distort. So the other parameter to look for is Xmax. If this is exceeded, distortion will occur
 

Muthusami S

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ok guys been following this thread. Too much speculation going on.

There are flaws being made with regard to fundamental aspects. First of all ultrasonic and infrasonic refers relative velocity of a body with relation to speed of sound at MSL (or given conditions). This is also called Mach no. So in one way we can say that speed of sound is mach 1. Speed of sound does not depend on frequency. So you will have a 20 hz wave and a 20k hz wave traveling with same velocity. That??s Point not 1. We don??t call this infrasonic, ultra or supersonic. We simply refer to them as lows, mids and highs (ya it does'nt sound as fancy as 'supersonic' but it is more audiophilic. what say?).

2nd point is bass reflex ports are not provided to ??reinforce?? bass response although that is the perceived effect. Any driver has to be mounted in a minimum enclosure volume called the ??compliance volume??. This is the behavior of driver when it is in free space radiation in an infinite baffle. Compliance volume is given by manufacturer of driver during design and testing. If we cant get an enclosure that??s close or greater than the compliance volume we resort to ??ports?? to trick the driver into thinking it is in a larger enclosure (ya , this way we may tune frequencies that need to be emphasized with port area). We can get a ported system to perform like a sealed and vice-versa. It is impossible to find out if a ported or a sealed system is playing in a blind test

3rd point is that no small speaker with any amount of gimmickry/technology can outperform a bigger driver. If it does, it means the bigger driver was badly designed. It is not the strength of a small driver. In similar quality, construction, material selection and design, bigger driver will outperform a smaller one (with regard to low frequency extension)

Magnet is right when he says ??A large well designed driver will definitely have the motor force to deal with the larger piston, plus it will move less for the same sound pressure levels which is a clear advantage??

As to the question he has posed this is my answer. If the large driver has an Xmax (max cone excursion) of 3 mm and we move it 5 mm it will distort. If the small driver has a cone excursion of say 18 mm and we move it only 15 mm if will not distort. So the other parameter to look for is Xmax. If this is exceeded, distortion will occur

Flanker,

One more eye-opening post; especially the 3rd point. Thanks a lot.
 

akshayjha

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For a sealed cabinet design, as the dia of the driver increases, the internal volume of the cabinet has to be increased exponentially (compared to lower dia woofer cabinets). Because of the massive size of a sealed cabinet that would be NECESSARY to produce lower frequencies (or atleast to come close to the resonant freq) people have diverted attention to bass reflex speakers with smaller dia speakers. In this way, u would get best of both worlds (smaller size cabinets and better efficiency which is greatly compromised in sealed enclosures. A badly designed 15incher would sound worse than a nicely designed 6.5 incher....
 
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spirovious

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My views-

I beleive as Dia increases ,lower freq are expressed acurately.
I crossover is not made perfect,then voice Q can bcom thicker.

I feel

For frequency above 10k- 1in tweeter (aluminium is better)
above 1k- 3 to 4in (vocals )
below 1k- 6 to 8in (Bass)
 
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