What's the best/ optimal bass driver size ?

[Pearljam5000]

Yes obviously bigger driver = more bass
But what's the optimal size for clean and tight bass in either a speaker or a sub ?
And Also is it better to have 1X15 inch driver or 2X8 inch instead etc ?

 

[TankTop]

To start 4 8” drivers are closer to a single 15”.

 

[Pearljam5000]

To start 4 8” drivers are closer to a single 15”.

Lol
I need a calculator for this stuff

 

[TankTop]

Lol
I need a calculator for this

7.5×7.5×3.14
4×4×3.14.

 

[BrokenEnglishGuy]

7.5×7.5×3.14
4×4×3.14.

i dont understand this hehe
But i memorized the result from the calculators for myself xD

dual 6.5'' => 8''
dual 8'' => 10''
dual 10'' => 12''

if i remember well dual 12'' are 15''~ and yeah as tanktop said 4 x 8'' are something around 15''
----

The thing is, it depend a lot of the resonant freq from the driver, and also the linear Excursion from the driver
There is some drivers around 5-+mm and others like 10-+mm

 

[sarumbear]

Lol
I need a calculator for this stuff

Piston Excursion calculator

www.baudline.com

 

[LTig]

7.5×7.5×3.14
4×4×3.14.

This covers only the area. Usually larger drivers have more excursion so can move more air than multiple smaller drivers with the same combined area.

 

[Ciobi69]

I did set in with dual 18 inch unlimited power

 

[kemmler3D]

Asking "what's the best size of driver" is like asking "what's the best vehicle".

It mostly depends on the frequency range you need it for.

A 12 or 15" is typically going to do the best in the 20-100hz range as it needs less excursion for a given SPL than a 10" or 8".

However, if you need to run it up to 200-300hz+ and you don't care about the bottom octave (20-40hz) then a 10" or even 8" might be cleaner and deliver the needed SPL. I've done some looking for my own (theoretical) DIY build and not too many large diameter drivers have the lowest possible distortion above 200hz.

There are a lot of exceptions but they tend to be expensive, like the JBL 2216ND which is run all the way up to the tweeter in the JBL M2. It's also $435.

So TL;DR it depends on whether it's really just for subs or you need to go well above 100hz. If not, get the biggest driver you have the room for, but make sure it's suited for actual sub bass and not Pro Audio sub-bass that bottoms out around 40hz.

 

[sigbergaudio]

I don't think there exists an answer for this.

 

[Zek]

The calculation is not correct ... it should be like this ...

 

[Duke]

... what's the optimal size for clean and tight bass in either a speaker or a sub ?

There is no universal answer to that question... other than "it depends."

If we're talking about subwoofer frequencies only, imo multiple smaller subwoofers intelligently distributed will produce smoother in-room bass than a single large subwoofer. On the other hand the T/S parameter values for a large woofer usually result in deeper bass than from multiple smaller woofers.

If we're talking about a woofer that goes in a main speaker, I'd look at the system design as a whole rather than focusing on the woofer in isolation. What woofer characteristics would result in the best match for the midrange driver (or tweeter, if it's a two-way)?

And as far as getting "clean and tight" bass, take the room into account as much as you can. From there, look at the T/S parameters and enclosure design. Use a woofer with thermal and mechanical power handling that will keep up with the rest of the system, taking into account any EQ you plan to use. There is little point in using a woofer that is overkill... like if your midrange driver can only do 105 dB, there is little to be gained by having a woofer that does 115 dB, unless that is the only woofer whose other characterstics meet your requirements.

In my opinion.

 

[Lbstyling]

On top of the items listed above, dynamic compression is also a factor.

For example driver/box simulation software suggests that large xmax capable drivers with output capability of say 82db at 1w will deliver 115db at 2048w if within xmax.

In the real world, putting 2000w into a thin coil of copper will generate lots of heat and nowhere near this much SPL.

Once you start to put much more than 100w into a coil, compression progressively steals your theoretical SPL gains away.

Dynamic compression can be reduced in driver design by:

Adding cooling fins, venting the pole (hole in the middle of the driver), extending the pole (solid dome in the center of the driver that faces forward), enlarging the area of the magnet assembly etc.

or by increasing the efficiency of the driver via moving assembly weight reduction and/or increasing the magnetic force in the gap (smaller tolerance magnet gap/higher Tesla magnet material/FEA optimizing the magnet shape better)

With most of these factors, when you change them, it has knock on effects on other factors that may not be wanted. For example: extending the pole piece forwards reduces SD and hence peak output and efficiency. Reducing the weight of the moving assembly increases FS which reduces natural low end extension.

It's a tough game for a designer.

I can tell you this though, those who would choose to take a long excursion 15 inch sub in a small box with 1000w of amp over a 18 inch JBL 2452 (99db/1w) with its tiny 9mm xmax and 300w chose dead wrong.

 

[DVDdoug]

What's the best/optimum bass driver size?

...Yes obviously bigger driver = more bass

You (correctly) answered your own question.

Size matters but there's LOT more to woofer design than size and bigger isn't always better. But you're not going to get realistic bass that you can feel in your body from a 6-inch woofer.

Are you building or buying? Or just asking?

If you are buying, check the specs/measurements (although you can't always believe them) and listen if possible. If you are building, there is software that can model a particular driver (using the Thiele-Small parameters) in a particular ported or sealed box to predict performance and optimize the design.

...I have a pair of 15-inch subs in large (about 3-feet tall) cabinets in my living room. Probably overkill but "adequate" for my listening. Some people have more/bigger woofers.

I need a calculator for this stuff

A spreadsheet doesn't hurt.

The area of 15-inch circle is 4 times that of a 7.5 inch circle. Or, if you have a 15-inch square you can fit one one 15-inch circle or four 7.5 inch circles inside.

Technically, the piston area only includes the moving-part of the cone.



P.S.
A lot of bass guitar cabinets use four 10-inch speakers. Apparently, this provides enough piston area while allowing the drivers to go high-enough in frequency to cover the full range of the instrument. When a 15-inch driver is used in a guitar amp/cabinet, there's usually a horn midrange-tweeter.

That's just an observation... Guitar & bass-guitar speakers are NOT designed for 'hi-fidelity".

 

[howard416]

The bigger the better. In a perfect world, your driver(s) would be so large, that at the require volume level, the excursion would be negligible. Of course, this is completely impractical since almost no one has space for a 24” driver and, for the crazy bassheads, they probably don’t even make 36” drivers (anymore?).

 

[dfuller]

How long is a piece of string?

 

[Pearljam5000]

The bigger the better. In a perfect world, your driver(s) would be so large, that at the require volume level, the excursion would be negligible. Of course, this is completely impractical since almost no one has space for a 24” driver and, for the crazy bassheads, they probably don’t even make 36” drivers (anymore?).

22 inch woofer

 

[Lbstyling]

A lot of bass guitar cabinets use four 10-inch speakers. Apparently, this provides enough piston area while allowing the drivers to go high-enough in frequency to cover the full range of the instrument. When a 15-inch driver is used in a guitar amp/cabinet, there's usually a horn midrange-tweeter.

That's just an observation... Guitar & bass-guitar speakers are NOT designed for 'hi-fidelity".

Sounds like we need to introduce these people to the AE TD15m!

 

[stevenswall]

Disregard size/power/excursion/every other single point of reference and go based on calculated air moved or better yet, measurements.

There are some 12" and 15" drivers that are utter garbage compared to a dual 4" on a Devialet Phantom Reactor.

 

[Pearljam5000]

How long is a piece of string?

Why the sarcasm