[BrassEar]

I have Martin Logans as a reference but I heard some DIY OBs today that really shocked me. 

This guy I know built his own OB with Focal 6.5" coaxial car speakers. The speaker is pretty much a vertical 10-inch wide board and four feet tall with the Focal coax mounted close to the top. There is just a cap on the tweeter as the mid is full range. He also has two sealed DIY subs for 100Hz down.

Long story short, this super cheapo speaker gives my Martin Logans a very serious run for overall sound quality. Has anyone heard of such a thing? I am still shocked from the listening experience, especially at the price.

[kingdeezie]

I have never heard of this, but it is actually pretty clever considering the Focal drivers would be not typically be used in a box of any kind and just mounted to the door panel.

I can't see how this could equal the Martin Logans however, but I could be wrong.

I remember from my car audio days, anything coaxial, with that big, giagantic tweeter housing right in front of the woofers, would lead to noticible distortion. You got significant improvement when moving up to the a seperate tweeter and woofer component system. This was from what I heard from the Infinity anyways.

 

[BrassEar]

Well this has tweaked my interest enough to try a similar project using an OB panel with a P-Audio BM12CXA 12-inch coax with a 3.3 uF cap first order crossover.

[mcgsxr]

Years ago Dan Mason suggested that folks play around with car audio drivers on OB as a cheap way to try it out.

I have done so in the past, and it is a surprise how good it can sound.

[Bob in St. Louis]

If memory serves, "John in CR" was playing around with 6x9 GM car speakers.

Good idea though, and the driver choices are plentiful.

Bob

[opnly bafld]

Years ago Dan Mason suggested that folks play around with car audio drivers on OB as a cheap way to try it out.

I have done so in the past, and it is a surprise how good it can sound.

That is how I started, went to the local car audio shop and tried it for free*. 

Lin

*a friend owned the shop

[embty2002]

I have Martin Logans as a reference but I heard some DIY OBs today that really shocked me. 

This guy I know built his own OB with Focal 6.5" coaxial car speakers. The speaker is pretty much a vertical 10-inch wide board and four feet tall with the Focal coax mounted close to the top. There is just a cap on the tweeter as the mid is full range. He also has two sealed DIY subs for 100Hz down.

Long story short, this super cheapo speaker gives my Martin Logans a very serious run for overall sound quality. Has anyone heard of such a thing? I am still shocked from the listening experience, especially at the price.

Hello,
about the Focal 6.5" coaxial car speaker. is this?

http://www.focal.com/it/audio-auto/altoparlanti/kit-coassiali/pc-165.php

very interesting, 10khz without tweeter qts 0.73

[embty2002]

Hello,
i waiting for a pair of Focal PC 165 coaxial car speaker 6,5 inches , for 125 euros shipped Italy to Italy.
i will play them in OB, i'll give you some notices.   
 i'm satisfied about my alpha 15 in 70cm panel, but i would change my Audio Nirvana super 8.
bye

Giuseppe

[zipidachimp]

pardon my ignorance:  won't you break something if you use 4 ohm units with an 8 ohm receiver?  receivers are expensive to replace. just wonderin' .

[embty2002]

Hi,
My Focal PC 165 just arrived yesterday.
i use it with a behringer CX2300 active crossover, with a 125watts 8ohm AB power amplifier for Alpha 15 and a Icepower 50ASX2 25watts 8ohm for Focal coaxial, but Focal are 4ohm so the Icepower has 40 watts.
i don't think that 4ohm 40watts is a problem for my Icepower power amplifier, it works fine, now.
Focal PC 165 has a real 100Hz bass in OB, it's amazing for a 6,5 driver.
my active crossover setup is 90Hz cut on the Alpha15, and 120Hz cut on Focal.
with 90 Hz on the Focal PC 165 is a surplus in that bass region, 120Hz cut works fine.
now, i wait for 100 hours running 
Bye

Giuseppe

[embty2002]

Hi,
i post some photos about these very very good Focal driver.
and some photos about AEQ DRC result with my behringer DEQ 2496.
the cutting point in active crossover are 120hz for Focal and 90hz for Alpha 15, the size panel is 70cm.
the Focal PC165 has a 125hz at zero gain, and a regular trend to the 10Khz , for me.
after 10Khz is the central tweeter , with zero gain on 20Khz. better than the Audio nirvana super 8.
with the correction room on the alpha 15 , the sound is more clear with a very
good deep image.
in the future, i think to build a H-frame for Alpha 15 with a separate panel for Focal.
is good idea?

Hello

Giuseppe









the rear is like a mirror

[same64]

Any updates on performance?.

[opnly bafld]

in the future, i think to build a H-frame for Alpha 15 with a separate panel for Focal.
is good idea?

Yes, or at least make your baffle narrower by the Focal.

[jacozz]

embty2002

Nice work!
I would suggest that you put the EQ setting at 20Hz at "0" or even - "12 "instead of +"12".

Why?
Your bass drivers can't cope with that much EQ without reaching X-max at very low amplitude.
Unless listening at very low levels I wouldn't recommend it.
In fact, I chop everything below 30 Hz in my OB, and it gives me a much tighter sound + I can play stupid loud.

Another tip would be to use the parametric EQ on your Behringer. It gives you better, more precise control over room modes adjustments.

Cheers!
/jacozz

[zipidachimp]

how about using a pair of 8 ohm ceiling speakers, in place of car speakers? worth a try?

[embty2002]

embty2002

Nice work!
I would suggest that you put the EQ setting at 20Hz at "0" or even - "12 "instead of +"12".

Why?
Your bass drivers can't cope with that much EQ without reaching X-max at very low amplitude.
Unless listening at very low levels I wouldn't recommend it.
In fact, I chop everything below 30 Hz in my OB, and it gives me a much tighter sound + I can play stupid loud.

Another tip would be to use the parametric EQ on your Behringer. It gives you better, more precise control over room modes adjustments.

Cheers!
/jacozz

Thanks, 20-25hz are to zero,  more better.   
Focal PC165 has a very good perfomance in voice and middle-bass, the tweeter could be adjusted.
i will change the electrolitic capacitor 2,5uf with a mkp 2,2uf+0,33uf paper oil russian.
i think to change my berhinger DEQ2496(transformer output stage)+kingrex pre-amp+behringer cx2300 analogic crossover
with a RME fireface 400 or m-audio profire 610 and use the audio card as DRC and digital crossover 3-way.
is it a good idea?

hello

Giuseppe

[embty2002]

Now, i'm listening with a m-audio 410 firewire.
i'm using the foobar crossover plugin with 110hz low-pass 36db cut over the Alpha 15 and a high-pass 120hz 6db cut over the Focal Pc 165.
this setting over the alpha 15 give me a very clear sound, and the Focal has very good details and deep soundstage, i'm happy 
i connected directly the m-audio with my two poweramplifiers, and using the m-audio panel volume control.
bye

[opnly bafld]

Thanks for the update Giuseppe.
Sounds like you are getting your system dialed in. 

Lin

[embty2002]

Hi,
last update:
I separated the mid-woofer and the tweeter around 3khz , with the active crossover (m-audio 410 + foobar + Allocator VST plugin ).
the mid-high increased to another listening level, for me..  high details in voice and deep image.
changed the alpha 15 with R1524, very clear bass like night and day.
Thanks to Scorpion
 my system is a 3 ways, now .
bye

[BoJonJovi]

Decades ago when I was kid I had a friend that worked in a junk yard. He suspended some spekers by springs in a box with no baffle and ran them with a car stereo. They sounded great. Car spekers typically have high q so it all makes perfect sense to me.