Car audio versus HiFi drivers in ELF or Linkwitz subwoofer

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halfgaar

halfgaar

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Joined 2005
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I was wondering how suitable car audio drivers are for use in home HiFi subwoofers, especially in the case of extended low freqency or Linkwitz transform. When I built my sub, I didn't want to risk getting a car audio driver, so I chose the highly recommended Peerless 830847. A friend of mine is designing the same type of sub now, and this time, I'd like to have some more concrete information before we pick a driver.

For example, in WinISD Pro simulations, the JL Audio 13W1v2-4 performs really nice: better excursion figures and almost identical power requirements for the same SPL.

Car audio drivers tend to be available in larger diameters than home subwoofer drivers, which is very convenient for equalized operation such as ELF or LT, but posts such as this one kind of warn against using car audio drivers.

Any (concrete) advice on this matter is appreciated.
 
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sreten

R.I.P.
Joined 2003
Hi,

Things can go wrong in subwoofer design and you cannot "see" it.
For both hi-fi and car audio. Distortion levels cannot be inferred.
Generally hi-fi drivers are better designed, but not always.

Concrete information is hard to come by, and as you surmise
there is no such thing as useful "concrete" generalisations.

:)/sreten.
 
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sumsound

Member
Joined 2006
I am always tooting my horn for the Lab 12 driver for sealed Linkwitz Transform/ELF designs.

I'm about to build a Quad .707Q lab 12 box with 2kW of ICE amp.

It should be capable of 111dB 2KW 1M @ 20Hz

thats with ~4 cu' Vt.

IMO its a tremendous value for the quality of the driver.

I have already built 3 Dual sealed boxes with this driver.

and 4 Ported boxes.

Very high quality construction, very low distortion.
 
halfgaar

halfgaar

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Joined 2005
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WinISD Pro has the Lab 12 in its library and I just compared it to my Peerless 830847. The Lab 12 is much more erratic, even with Qtc=0.707. Even the LT filter doesn't compensate for it. But other than that, it behaves very similarly to my Peerless, in both power requirements as well as excursion.

BTW. What exactly constitutes a "professional" driver? Would this Eminence Lab 12 be (that much) better than my Peerless 830847?
 
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sreten

R.I.P.
Joined 2003
Hi,

Erratic ?

http://www.klippel.de/pubs/Klippel ...linearities–Causes,Parameters,Symptoms_06.pdf

See Section 7.3 regarding a 12" auto high excursion sub :

"Loudspeaker 3 is an example of a speaker which is optimized for linear Bl(x) and Kms(x)
characteristic by using a long voice coil, a carefully designed magnetic path and a two-spider
suspension. Despite the development effort, final cost and weight of the product the driver
produces a highly distorted output due to the neglected Le(x) and Le(i)-nonlinearities.
Applying some means for shorting the ac-field can improve loudspeaker 3 significantly"

Is the sort of thing you cannot infer from specification or parameters.

FWIW if yopu have the Peerless changing it to the LAB12 or any
of the other similar high performance 12"ers seems pointless.

:)/sreten.
 
halfgaar

halfgaar

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Joined 2005
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Erratic ?
Click to expand...

I merely meant that the curve is non-smooth. I'm used to seeing a characteristic bump at the resonance frequency, but this curve goes up and down even below resonance, which is quite unusual (at least, to me).

Thanks for that PDF, I will have a look at it.

FWIW if yopu have the Peerless changing it to the LAB12 or any
of the other similar high performance 12"ers seems pointless.
Click to expand...

I was not about to replace my driver. That friend of mine and me are just figuring out if he should use the same driver as I do, or another one.
 
A

aubergine

Member
Joined 2008
'Professional drivers' to me are simply a marketing division that lots generalize about. They are marketed at the people in the pro audio business.

They do come in quite large diameters as well, as you know.

If you like the LAB12, I also suggest you model the Ciare xx.00 SW series.
 
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sumsound

Member
Joined 2006
halfgaar said:


I merely meant that the curve is non-smooth. I'm used to seeing a characteristic bump at the resonance frequency, but this curve goes up and down even below resonance, which is quite unusual (at least, to me).

Thanks for that PDF, I will have a look at it.



I was not about to replace my driver. That friend of mine and me are just figuring out if he should use the same driver as I do, or another one.
Click to expand...

I have not used Win ISD for modeling the Lab 12 I use a Bass Box pro that actually super imposes the HF response of the driver onto the graph.

In a sealed sub with the lab 12 ~ 1cu' frequency response is not erratic. Bellow 150Hz. The driver does peak at 1kHz but it is not designed to be operated anywhere close to that.

Here is a graph. Of a lab12 in a vented and sealed box

LABS.jpg


I have real sweeps of a lab 12 in a sealed box also but not here.

If you see a bump at box resonance in your prediction that is not a .707Q Its probably in in the .8 or .9 range
 
halfgaar

halfgaar

Member
Joined 2005
halfgaar.net/
If you like the LAB12, I also suggest you model the Ciare xx.00 SW series.
Click to expand...

I can only find one subwoofer driver with SW in its name on the Ciare site. That would be the CSW4000. I haven't modeled it, but an open air resonance frequency of 30 Hz seems a bit high for equalized use. Also, an Xmax of 20 mm and claimed efficiency of 92 dB? That voicecoil is probably overhung, which means that that efficiency cannot be reached by far. Oh well, published efficiency specs are not to be trusted anyway.

'car' usually means a more harsh environment... humidity / heat / etc.
Click to expand...

I would kind of expect that car audio drivers are also of lesser quality when it comes to distortion, because subs in cars aren't usually meant for refined reproduction, but for a lot of SPL instead.

@sumsound

After looking at it again, I can see that it is not that erratic, but the response curve is somewhat strange for LT compensation (modeled enclosure has Fc of 45 Hz):

lab12-lt.png


LT usually has a perfect 0.707 curve.

You know, I've had the hick-ups for the last 30 minutes... Do you know how annoying that can be...?
 
S

sumsound

Member
Joined 2006
Lab 12 @ .707 usually has an F3 @ around 50 or 53Hz

Does win ISD take cabinet fill into account.

I normally model mine with heavy fill.

That response curve you generated looks like a much lower Q than .707

Infact it looks like ported response.

What is the volume of that box??
 
S

sumsound

Member
Joined 2006
Q of .703 shouldn't be to far off from .707

But you will get different results with various volumes with and without fill.

I'll take a look at your cab volume when I get home.

I don't know if you can get the LAB12 for as good a deal in the netherlands, but it can be obtained for around 120-150 US Dollars here in the states.
 
S

sumsound

Member
Joined 2006
halfgaar said:
@Sumsound
The graph is equalized with LT, hence the lower F3.

WinISD does not take fill into account, as far as I know.

Volume=53l, Fc=42Hz, Qtc=0.703

@Spasticteapot
Passed the info on, for him to try and model.
Click to expand...

In an unstuffed box of 53l I get a QtC of .7
If you add heavy damping the Qtc goes to .585

In either case the driver exceeds xmax @ full power bellow 40Hz

If you build a heavy fill box with a Vt of 32.15L you will have a .707Q and not have to worry about exceeding Xmax even down at 1Hz.

I've built a few of these sealed subs already and am in the process of building a 4 driver version.

With 2kW 111dB @ 20Hz

Have fun.
 
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