# JBL 660GTi Component Midwoofer Testing



## ErinH (Feb 14, 2007)

One of the best midwoofer drivers I've tested and seen data on.

See here for full data and some analysis (make sure to read the conclusion before you ask what I thought ):
JBL 660GTi Midwoofer Testing | Medley's Musings


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## quality_sound (Dec 25, 2005)

Holy crap! Flat to 3 and usable to 5?! And here I said I wasn't going to replace my QSDs... lol

Speaking of, wanna a full OS 3-way Quart set? QTD-25, QWD-100 and QWD-160? With or without passives.

Oh, I have an OS Eton-made Diamond HEX 4" mid as well.


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## rimshot (May 17, 2005)

wow that's badass! WANT!


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## thehatedguy (May 4, 2007)

That's what high end from HI can do...probably similar to the Synthesis home speakers.


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## bbfoto (Aug 28, 2005)

Oh, that mid is complete crap!  Might have to trade my Seas W18NX's for these after the shootout, LOL. Time will tell.

Erin, when are you gonna get to testing the GTi tweeters (with and without the wave guides)???


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## bassfromspace (Jun 28, 2016)

I'd like to see this driver matched up against the SPZ 60.


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## quality_sound (Dec 25, 2005)

bassfromspace said:


> I'd like to see this driver matched up against the SPZ 60.


I don't think the Z60 will hold a candle to it. Especially given the cone area difference.


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## bassfromspace (Jun 28, 2016)

quality_sound said:


> I don't think the Z60 will hold a candle to it. Especially given the cone area difference.


They're both 6's, but I think you're right.


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## quality_sound (Dec 25, 2005)

In name. Boston has always done true 6" mids but the JBL should be at least a 6.5" driver.


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## bbfoto (Aug 28, 2005)

The actual diameter of the outer mounting flange (not including the screw tabs) is 6-5/16".

Interesting that JBL/Harmon list the xmax as _just_ 5.36mm. I guess this works out just right when considering the BL/force factor outward offset at rest of nearly 2mm that Erin tested (linear one-way xmax as 7.4mm), if I understand the specs correctly? JBL's listed Fs is just off by about 2Hz and Le is spot on.

Link to User Manual and Specs:

http://www.jbl.com/resources/Brands...-US/OwnersManual/560GTi660GTiOMrev3_20_07.pdf

Kind of a bummer that JBL's top range component set is "Made in China", but if the unit-to-unit build quality is good and it performs as tested I guess it keeps the end price to the consumer lower and/or gives JBL a good profit margin.


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## matdotcom2000 (Aug 16, 2005)

Straight up the best midbass I have ever owned and I have owned quite a few....


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## Melodic Acoustic (Oct 10, 2005)

The 660Gti uses a great and costly Balanced Neo motor design. 

Large Voice coil and great motor with some type of stabilizing system and of course copper cap or ring. Now give it a high-ish QMs and it becomes fast and clean and very controlled with its inward and outward movement. 

Add a very nice mid/low fs to ensure the Sensitivity is High and it is high compared to most Mobile Audio based drivers with that much linear movement and with large diameter voice coil. I hate to say it, but it goes to show once more a low fs is not that important for lower end performance when it comes to good clean mid/bass with impact. Control and Sensitivity is a big part of it. Before if starts a lower fs and lower sensitivity can work amazingly, if the driver can handling some power. Just different ways of doing things. O ya and a ton of Xmax is not need either. The GTi design has a good bit of both.

But,

The JBL driver tech is how you get that type of performance in a driver with a mounting depth of what 3" or a hair over. Do not remember been a little over 2 years since I install my last set. 

The cost of that set i can beat is mostly do to the tech in this wonderful mid/bass. So it you can find them a good price I would not hesitate if I was you to pick them up.


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## bbfoto (Aug 28, 2005)

^Hmmm...6.5" Arian's or 660GTi mids? Decisions, decisions... 


Hey, does anybody here have a set of the 6.5" mids from the JBL 608GTi MKII set that can be sent to Erin for testing??? It's supposed to be a monster midbass and not far off from the 660Gti mids. I'm sure bikinpunk needs more drivers to test right now!


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## eviling (Apr 14, 2010)

bikinpunk said:


> One of the best midwoofer drivers


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## ErinH (Feb 14, 2007)

honestly, guys, this thing is really amazing. I demo'd it earlier by itself on the test baffle and was very impressed. it wasn't a blind test, so my subjective thoughts will end there. suffice it to say, if JBL were to make this driver readily available by itself (or in a set) as opposed to the component set, I think they'd do a whole lot of business. I've seen a lot of drivers in my short 5 years in this hobby and this particular one is at the top of that stack next to some very, very highly regarded others.


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## BuickGN (May 29, 2009)

Very impressive, I'm happy these are going to the blind listening test too. Is it safe to say this has one of the flattest, if not the flattest FR of any 6.5" tested?


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## ErinH (Feb 14, 2007)

don't look at the FR posted in this thread for FR representation. that was done in the nearfield and any measurement in the nearfield will corrupt the high end portion of the measurement. I explain this on my site in the test methods page (which is linked before the data for the JBL starts). every driver will look much better in the nearfield when it comes to upper end response. 

i only posted the picture above to show HD. so for FR results, look at my site, please. 


*assuming you're talking about that picture. if not, I'm stupid. *


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## quality_sound (Dec 25, 2005)

I wish I still had my old HEX 7s. I know the 4.5s have great extension but they should at that size.


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## audionutz (Dec 22, 2005)

Lowest distortion (audible) of any small driver I have ever used. Nice output too. I used mine for a few years band-limited from 60-250 IB in the doors of Big Meat. In fact, I only recently removed them for two reasons: First I had door rattle that I could not control within the door latch mechanism. Second, I missed my high efficiency kick panel setup (another JBL driver...go figure  ).
IMHO, JBL makes stellar drivers for the bottom HALF of the spectrum.


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## lucas569 (Apr 17, 2007)

ive always had my eyes on these, you made my decision that much easier.. thanks for the info. 

i only wish these were sold raw.


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## Patrick Bateman (Sep 11, 2006)

The GTI midranges remind me of a Porsche 911. There's engineering in here that's been refined over DECADES.


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## tnbubba (Mar 1, 2008)

oops and the listening test it got rated as a wanna be..


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## thehatedguy (May 4, 2007)

I believe the data.


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## subwoofery (Nov 9, 2008)

Seems like people need some form of low frequencies to find it pleasing and translates into added warmth... 
Would love to see the freq response of each drivers @ the listening spot. 

Kelvin


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## subwoofery (Nov 9, 2008)

Seems like people need some form of low frequencies to find it pleasing and translates into added warmth... 
Would love to see the freq response of each drivers @ the listening spot. 

Kelvin


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## clix`g35 (Aug 23, 2009)

Kelvin, 

The klippel shows these to have a good amount of low end extension, but also have a good impedance peak in the lower frequencies. When running this active would you need to EQ in order to flatten the woofer response, since the woofer needs more power in the lower frequencies?


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## thehatedguy (May 4, 2007)

Nope I wouldn't think so.


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## subwoofery (Nov 9, 2008)

I thought that flattening the impedance peak helped the driver react better to more power at low frequencies... 

Kelvin


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## Oscar (Jun 20, 2010)

You can 'zobel' mids and tweets for sure, but any woofer with a decent motor should be damped enough that you shouldn't get excessive ringing, especially with something of this caliber.


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## thehatedguy (May 4, 2007)

If it needs more power at lower frequencies...the bump is going to limit and reduce it at resonance, where it needs the least amount of power.


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## jimbno1 (Apr 14, 2008)

Glad I did not sell my 660GTi  I did some subjective listening against the Alpine F1 Scan Rev, Illusion ND6.1, and Hertz ML1600 and I thought it was the best of that bunch. Good to know my opiniion has some objective backing. 

Any interest in testing the OS 408GTi mids? 

The OS 600GTi midbass seemed to have even more low end output and extension than the 660GTi's. They were designed as a dedicated midbass and really sounded crappy above 1 KHz to my ears anyway. But I bet they have some serious X-max. 

Now what tweeters to pair with the 660GTi midbasses?


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## tnbubba (Mar 1, 2008)

didnt think it tested that good int he shootout..esp for the $$$$$$$$$$$$$


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## subwoofery (Nov 9, 2008)

tnbubba said:


> didnt think it tested that good int he shootout..esp for the $$$$$$$$$$$$$


You were part of the shootout? 

Kelvin


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## bbfoto (Aug 28, 2005)

clix`g35 said:


> Kelvin,
> 
> The klippel shows these to have a good amount of low end extension, but also have a good impedance peak in the lower frequencies. When running this active would you need to EQ in order to flatten the woofer response, since the woofer needs more power in the lower frequencies?


The post below might help regarding your question...



pionkej said:


> Jerry,
> 
> Thank you for undertaking all of this. I'll admit that I'm actually not one bit surprised that my 660's wound up in the middle of the pack. Out of the box, they DO have a very mellow and rolled off bottom-end (which your comments seem to point to being the largest drawback). Luckily, my 6to8 can apply a shelf filter in the crossover section and knocking down 80hz and up by about 6db's really brings these things to life. Erin's testing shows JBL underrates their excursion numbers and I took advantage of that by extending the low-end response through equalization.
> 
> Please don't take any of my above comments as contradicting your results for the 660. I honestly agree with them. I simply wanted to share that with the proper setup and some EQ work a driver that doesn't perform perfect "out of the box" CAN still do VERY WELL. In the case of the 660's, I personally believe they can hang with some of the Tier 1 drivers you tested...which is why I still rock them!  Thanks again!!


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## eviling (Apr 14, 2010)

tnbubba said:


> didnt think it tested that good int he shootout..esp for the $$$$$$$$$$$$$


The secrete is they aren't expensive the 660's can be had for roughly 130 a piece direct from harminsadley it looks like they are being discontinued. I keep getting different answers on stock issues while trying to order mine than usually if I push I almost always get the real answer that they are discontinued. 

I am still looking for a 660 mid range to complete my set  
Sent from my EVO using Tapatalk 2


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## thehatedguy (May 4, 2007)

Say what? $130 each, where? PM that...lol.


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## rexroadj (Oct 31, 2008)

harmon direct! Customer service....ask for non warranty replacements

But good luck!!!!

The replacement costs on the C608GTI mids were double


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## vactor (Oct 27, 2005)

so are the 660 mids available or not? i never get a positive response from harman and they are not listed on their site  i'd buy a few sets if i could !!


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## rexroadj (Oct 31, 2008)

As far as I know they are not available.....they say yet, implying that they will soon, but if they are discontinued then..............who knows? I'm sure they will carry some stock for warranty purposes at some point though? Maybe this issue is why they are being discontinued? Who knows....just my speculation


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## jimbno1 (Apr 14, 2008)

Who wants a third tier midbass anyway


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## rexroadj (Oct 31, 2008)

jimbno1 said:


> Who wants a third tier midbass anyway


No clue? But I would love two of them


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## eviling (Apr 14, 2010)

rexroadj said:


> No clue? But I would love two of them


I'm still looking for a single if anybody has one that's ne great I just need a single mid range  

Sent from my EVO using Tapatalk 2


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## rexroadj (Oct 31, 2008)

Ok, help Ray get one.....put them in a room together with some Barry White and send me the new pair


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## eviling (Apr 14, 2010)

rexroadj said:


> Ok, help Ray get one.....put them in a room together with some Barry White and send me the new pair


You never got back to my pm. Did you see I got an 09 impala

Sent from my EVO using Tapatalk 2


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## rexroadj (Oct 31, 2008)

Oh yeah....sorry Ray. I read it on my phone at work (pm) and never looked. Sorry, I will. Had no clue about the new car! hope it was want/not need (accident etc). I will take a look later at your new setup! Good luck with it!


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## eviling (Apr 14, 2010)

rexroadj said:


> Oh yeah....sorry Ray. I read it on my phone at work (pm) and never looked. Sorry, I will. Had no clue about the new car! hope it was want/not need (accident etc). I will take a look later at your new setup! Good luck with it!


Yeah I'm still deciding idk im kinda happy wuththe Bose lol

Sent from my EVO using Tapatalk 2


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## Elektra (Feb 4, 2013)

Didn't the Dyn Esotar E650 and Illuminator drivers test better? I would think those would be easier to get? Albeit a tad more expensive...


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## mitchyz250f (May 14, 2005)

Erin I noticed you measure compression from 1 to 6 voltes. Why not measure compression at a db level like from 85db compared to 105, 108 and 110db?


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