12" driver

H

Helge A. Bentsen

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Jan 19, 2011
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Oslo, Norway, Norway
drbentsen.no
I'm looking for a 12" driver with good low frequency extension and high sensitivity that fits in a ported box around 90 L .

I modeled a Lab12 and it's frequency extension looks good, I just wish it had a bit more sensitivity.

This is for a space and power limited application, I can get away with approx. 90L box volume and I have 350W@4ohm at my disposal.

Any suggestions?
 
Re: 12" driver

Helge Dr. Bentsen said:
I'm looking for a 12" driver with good low frequency extension and high sensitivity that fits in a ported box around 90 L .

I modeled a Lab12 and it's frequency extension looks good, I just wish it had a bit more sensitivity.

This is for a space and power limited application, I can get away with approx. 90L box volume and I have 350W@4ohm at my disposal.

Any suggestions?
Click to expand...

Extension or sensitivity, pick one.

Must it be a 12"? There are plenty of larger drivers now that will play in that volume.
 
Re: 12" driver

The Eminence 4012HO looks good compared to the Lab 12 in a small box, but like Phil says extension or sensitivity, pick one, the Lab12 has slightly more bottom, the 4012HO more top.
 

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Re: 12" driver

I was thinking about a 12" since I started this research with a Lab12. I have room for a bigger driver. This quest is about getting a good frequency extension and a reasonable SPL level from a given maximum volume and the available power :)

Btw: I can get 550W@2ohm from the amp, so I´m considering two 4ohms drivers as well.
 
Re: 12" driver

Helge Dr. Bentsen said:
Yes.
Click to expand...

Helge,

What is the use case here? There are a number of very good 15" drivers out there that both in pro audio, and home audio drivers built like pro drivers. There's is a big difference for aiming in response to 40Hz at 95dB sensitivity, versus response to 20Hz at 89dB sensitivity for a home theater sub.
 
Re: 12" driver

It's a ported sub project for a car. Aiming for a -3 dB@ 30-35Hz and a sensitivity above 88dB per driver and good excursion control, since I don't have any HP filters available.

The current design is -3dB@30, 88dB per driver but suffers from a loss of excursion control below the tuning frequency that I find difficult to control.
 
Re: 12" driver

Helge Dr. Bentsen said:
It's a ported sub project for a car. Aiming for a -3 dB@ 30-35Hz and a sensitivity above 88dB per driver and good excursion control, since I don't have any HP filters available.

The current design is -3dB@30, 88dB per driver but suffers from a loss of excursion control below the tuning frequency that I find difficult to control.
Click to expand...

Helge,

Due to the pressure pot gain in the cabin of the car, I'd suggest a sealed box as the best fit, as the increase of the car's pressure pot gain is a good match for the 2nd order roll off of a sealed cabinet. Also, with no high pass filter available, any ported box you build is going to run into this same excursion restriction issue, it is only a question of what frequency is it going to happen at, as all ported boxes catastrophically unload drivers below the tuning frequency.

Personally I would buy this fifteen inch driver, wire the voice coils in series, and possibly use Parts Express' 90L knockdown enclosure for it. $200USD for the driver, a sealed box, and you're done.

Cheers,
 
Last edited:
Re: 12" driver

Helge Dr. Bentsen said:
It's a ported sub project for a car. Aiming for a -3 dB@ 30-35Hz and a sensitivity above 88dB per driver and good excursion control, since I don't have any HP filters available.

The current design is -3dB@30, 88dB per driver but suffers from a loss of excursion control below the tuning frequency that I find difficult to control.
Click to expand...

Kind of along the lines of Phil's post, is this target -3 point measured in the car, or is it the response of the box that you get when modeling with a basic T/S program (response in half space at 1M or something like that) or, to be completely silly, is it the response measured outside the car (with the speaker inside)? "Cabin gain" makes a huge difference here. As far as suggestions go, I think you likely are looking for the biggest cone you can fit. Do you have any dsp available? Since it is car audio, you may consider a non-conventional alignment with some smart dsp to compensate. Your power limitation comes into play but so does psychoacoustics...

[Don't forget to add a small vibrating device attached to the license plate holder...]
 
Re: 12" driver

-3dB target is inside the car, with humans present. I'd like to do this without any DSP because I don't have anyone available except my Lake LM26. I'm a bit insane about audio but maybe not that insane ;)

I had a look at a MiniDSP, looks like an option if I need some DSP power.


Sent from my iPhone
 
Re: 12" driver

Helge Dr. Bentsen said:
-3dB target is inside the car, with humans present. I'd like to do this without any DSP because I don't have anyone available except my Lake LM26. I'm a bit insane about audio but maybe not that insane ;)
Click to expand...

The pressure pot gain of the few cars I've stuck a measurement mic in starts between 60Hz and 80Hz, and tracks pretty closely the 12dB/octave theoretical output increase you would expect, so if you are trying to keep the response pretty flat, 60Hz is a reasonable F3 target for whatever sealed box you might choose to design.

That said, what many humans associate as "flat" in a typically home living room usually has a slight upward tilt in the low end, due to the pressure pot gain of the small listening room. When I do system tuning "flat" in larger rooms, where the pressure pot gain starts occurring below the frequencies reproduced by the PA, I sometimes add slight upward tilt in the low frequencies to make the system response more closely mirror that of listening in a small room.
 
Re: 12" driver

Phil Graham said:
Helge,

Due to the pressure pot gain in the cabin of the car, I'd suggest a sealed box as the best fit, as the increase of the car's pressure pot gain is a good match for the 2nd order roll off of a sealed cabinet. Also, with no high pass filter available, any ported box you build is going to run into this same excursion restriction issue, it is only a question of what frequency is it going to happen at, as all ported boxes catastrophically unload drivers below the tuning frequency.

Personally I would buy this fifteen inch driver, wire the voice coils in series, and possibly use Parts Express' 90L knockdown enclosure for it. $200USD for the driver, a sealed box, and you're done.

Cheers,
Click to expand...

Old thread, but I'd like to thank you for giving me the idea about a sealed sub.
I found a used Kicker solobaric 15" and have just completed a sealed box for it. It's 170L and measures +/- 2dB 31-80 Hz in my office. I've not gotten around doing any measurements in my car yet, but it sounds a lot better than my previous sub, more low frequency extension and a thigh, controlled sound. So far the only processing is a 3rd order BW LP@70 hz, doesn't sound like I need anything more.

It's fun :)
 
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