[JohninCR]

I finally got around to testing a pair of 6x9 car speakers that I picked up for $22/pr
to test an idea for bass augmentation.  They are virtually silent in mechanical operation
up to almost 15mm of point to point excursion, which mean I have a good 5-6mm of
useable Xmax.  They're made for free air operation so driver Q isn't an issue.  Other
than price, their major advantage is that they can be stacked in a much more efficient
use of space than a round driver.

Last night I was using just a pair in a small U baffle to test them out augmenting the
bass for a pair of small horns, and I was pleasantly surprised by how much bass they
put out and how good it sounded.  My plan is to use 6 per side and stack them vertically
in W/U baffle hybrids.  The resulting cab will be about 29" tall,  less than 10" wide, and
12" deep (a perfect speaker stand for whatever main driver I want to run on a small
baffle on top, since the mechanical operation will be cancelled with the W alignment). 
Since the manifold will be only 6" deep, I should be able to run them up past 200hz no
problem, so I can use almost any driver as a main driver.  The cab will be the equivalent
of an 18" driver on a 36" diameter baffle in free space, but in a very compact form that
is free from vibration. Plus the SQ in the bass region will blow away short cut takers
like the Bastanis with boxed bass with OB on top, with an even smaller cab.

I'm starting a big construction effort next week, so I'll have lots of pics of a number
of different speaker ideas very soon.

[Bob in St. Louis]

Keep us posted John.
Sounds like a fun build. You've been contemplating this for a while, I've been wondering what the status was/is.
Would definitely like to see "during/after" pics.

Bob

[amplifierguru]

Hi JohninCR,

A good subsonic filter to ensure that Xmax is only in response to 'in band' signals?

Cheers,
Greg

[JohninCR]

Another monkey wrench was thrown into the process.  I found some to try,
bought them, they work well, but now they're all sold, and I can't even find
them online.  Now I need to find something comparable with sufficient stock,
test it the same day and go back the same day to buy the quantity I need.

The problem is car audio has changed a lot, and subs are the norm.  As a
result many current 6x9's have an Fs in the 70hz range which simply won't
work.  Look for a claimed response from 40hz on up, nice size surround to
handle good excursion, good power handling, and somewhat compliant (not
overly stiff when you push in on the cone).  The Mitzu model MIT-69301 are
the ones I found that will work quite well in this application.  If you can get
the shop to demo one in free air operation, have them crank the deep bass
up and treble all the way down (better yet bring a CD with a sustained 30hz
tone on it), and back off of the power slightly when they start to distort or
make audible noise.  Then you can guestimate the point-to-point maximum
useful excursion by looking at the speaker leads where they attach to the
cone.  Bring a tape measure to make sure you're seeing more than a cm of
travel before you buy.

[tberd]

 I once laughed at a Chevy Citation with six cheap 6x9 speakers in the rear . Guy took the rear seat out and built a simple box . Speakers faced the dash . This was at a car stereo competition BTW . Car hit 126db and bounced the wiper blades off the windshield when the bass hit . Car had no subs or front speakers at all . Frequency reaponse was also extremely flat . Dude had like $700 in the whole system he said . So moral of this story is , when setup right 6x9's are no joke . Laugh away but the entire crowd had open mouths when his results came out .


tberd

[opnly bafld]

10 years ago I had a sedan with an aftermarket headunit, factory front and rear speakers, 5 ch amp, and 2 10"s in a sealed box.
Had to take the box out for a vacation to Florida. So I hooked the sub ch. up to the 6x9s in the rear deck.
When the trunk was empty in Florida the bass sounded horrible, but the 2 days driving each way, with the trunk full of luggage the sound was as good as the two 10s.

Lin

[Dmason]

They were talking about excellent quality/very inexpensive Kenwood car speakers on OB over at www.fullrangedriver.com awhile ago. I think this is an excellent thing, these 6X9's stacked, for bass. I like that better than anything else, based only on inclination, thus far. Good luck John, keep us posted. I am going to be looking for these Kenwoods this weekend, to start this project.

[JohninCR]

Hey Dan,

Be careful on getting today's 6x9's.  Now that subs are so common in cars many of the 6x9's serve as
a midranges with Fs in the 70's.  Bring a piece of cardboard with you as a makeshift baffle to make sure
you're getting something that makes bass.  I'm SOL until the one place that usually has significant
selection get another shipment in.  It's a real shame because these Mitzu's were perfect for what I need.

[opnly bafld]

Found 6x9 speakers at Wal-Mart for $10 each.
Durabrand DB69 poly cone and foam surround.
10 oz. magnet.
I placed it in an 18" x 18" piece of cardboard, it was not tight as I was just holding it.
I had it crossed over at 80Hz, output down past 40hz and even 30 at a little lower level.
Not real loud, I am not sure why at this point(maybe partly just 1 driver vs 2 I normally am testing?).
Please don't hold me to all of this because I tested these for about 10 min.
I will cut a piece of wood for more conclusive tests.
Floor gain and less cancellation through the hole in the cardboard should help.
Others are welcome to try these drivers for $10 ea. and report their findings.

Lin

[buble_corp]

Hi I'm new on this forum. I have Visaton B200 in OpenBaffle but the sound lacks bass and weight. My baffle is 25x125cm(10''x50'') with two 30x125cm(12''x50'') wings. I'd like to add woofer filtered with 10mH coil, change baffle width to 40cm(18'') and remove wings. I want to user Eminence Alpha 15'', couse it has Qts=1.26 ( http://www.pulseonline.com/eminence24.htm ) is cheap (60$) and available. Martin J. King used 2 per side in this project http://www.quarter-wave.com/Project07/Project07.html. What do you think about this one? Have anyone tried that woofer in OB with B200?

[opnly bafld]

Hello buble_corp welcome to AC

How did MJK cross it?   Freq.? slope?
I have not used that driver, but my experience using other big woofers is that the 6dB slope is too shallow and allows the lower driver to play too high to blend well with the B200.
If it can be used with a steeper slope it may work better.
IMO- FWIW

Lin