# JBL 400gti



## Patrick Bateman (Sep 11, 2006)

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I've noticed a lot of interest on this board in small woofers. I've recently measured a few for a project that I'm doing. Here are the *actual measured specs* on the driver. You can rarely trust the published specs, so these may come in handy.

Driver Name: JBL 400GTI
FS: 186.7hz
QMS: 7.8
QES: 0.85
QTS: 0.76
RE: 3.2
VAS: I was too lazy to measure VAS. JBL says it's 1.1 liters, and that seems accurate.

The 400gti is a funky driver, with a 4" cone and a neodymium motor. It has a ridiculous Dynaudio-sized voice coil, and it's power handling is absurd. It hasn't been made in 4 years or so, but you'll see them on Ebay occasionally.

If I'm not mistaken, it is the only 4" driver with a neo motor besides the AuraSound NS4. It offers higher efficiency and higher power handling.

It has a couple of downsides; the carbon fiber cone breaks up surprisingly early, and it has a high inductance due to the huuuuuuge voice coil.


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## 300Z (Mar 20, 2005)

Cool, that's the driver that I am currently using...  

I'm using it from 80hz 24db/oct up to ~1.5khz 12db/oct. And so far I think this is quite possible the setup I have been happiest... I like this mid better than the Dayton RS180-8 that it replaced.  

Leo


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## Patrick Bateman (Sep 11, 2006)

300Z said:


> Cool, that's the driver that I am currently using...
> 
> I'm using it from 80hz 24db/oct up to ~1.5khz 12db/oct. And so far I think this is quite possible the setup I have been happiest... I like this mid better than the Dayton RS180-8 that it replaced.
> 
> Leo


It doesn't really have any competition. The Auras can't handle as much power, and they're not as efficient. You need to cross it over low though, as the peak in the upper midrange is nasty.


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## 300Z (Mar 20, 2005)

Yes, the peak in the midrange area is bad; But in my car they are working quite well with those crossover points. But I need to play with it some more and get it dialed in some more.

But this is just something that I just threw together in a very short amount of time just to have some tunes... "pretty impressive" was the words I heard at our last GTG around here.  
I'm quite happy with them right now and most likely it seems they will be the mids I will settle with. Finally...  

Cheers

Leo


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## NaamanF (Jan 18, 2006)

The Scan 4" Revelators uses a neo mag. Different price range though.


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## Patrick Bateman (Sep 11, 2006)

I <3 the Harman Outlet -
They have the big brother to this midbass on sale for $171 delivered, per pair.

Audio Psychosis • View topic - Good Deal on a Really Oddball Midbass


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## DS-21 (Apr 16, 2005)

I'm sure those are great drivers, but I don't think they're what you're expecting. For one thing, they have a ceramic magnet I'm pretty sure. And the cone is metal.

That said, they're good stuff. I bought the size up, C608GTi, from Scott Buwalda last summer, and ended up putting them in my sister's car. I much prefer wider-range drivers on top, but can't complain about them. Don't think another separates set would sound better, with no EQ, etc.

The one with the mid that's that's the bigger version of yours is still 1500 USD, alas.


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## madmaxz (Feb 11, 2009)

Bringing back this thread to see if anyone knows how big of an enclosure these 400gti's need. I have them in .65-.70 liters and I think they want more. Thing is I'm pushing it with that. Maybe vent them? I have them lightly stuffed with pollyfill maybe really stuff it?


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## Patrick Bateman (Sep 11, 2006)

DS-21 said:


> I'm sure those are great drivers, but I don't think they're what you're expecting. For one thing, they have a ceramic magnet I'm pretty sure. And the cone is metal.
> 
> That said, they're good stuff. I bought the size up, C608GTi, from Scott Buwalda last summer, and ended up putting them in my sister's car. I much prefer wider-range drivers on top, but can't complain about them. Don't think another separates set would sound better, with no EQ, etc.
> 
> The one with the mid that's that's the bigger version of yours is still 1500 USD, alas.


Wow, nice catch!

That's quite deceptive - the ones that I have feature the biggest slug of neodymium I've ever seen on a midrange. I know that JBL can work wonders with ferrite, but they should at least change the name of the driver.


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## madmaxz (Feb 11, 2009)

How about enclosure size for the 400gti? How do you feel about .75 liter stuffed with poly fill? 175-200hz -18db - 3500hz -24db


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