Supravox field coils on JE Labs baffles

PaulFolbrecht · « **on:** 29 Mar 2009, 09:40 pm »

[Posted this on AA too but there are different readerships, it seems.]

Trying this setup again a year after I first played with it. Frankly, it is divine sound for amazingly little effort. That is, just the single 8" 215-2000, unfiltered, on the JE Labs-style baffle.

These drivers are new and still quite un-broken in, but there is one problem that I don't expect to go away with break-in and I'll probably want to address it (though it's not hugely objectionable).

This problem is that the bass is overly prominent. There is a lot of energy in the 60-100 Hz region. Some (or perhaps all) of this is probably due to the baffle hump.

I have a pair of TBI subs I would like to integrate to extend response down to ~20 Hz as well. These cross no lower than 50 Hz at 12 dB/octave, meaning turning them on is guaranteed to put more energy into the 50-100 Hz range which will not be an improvement.

So, I'm thinking the best solution might be a single inductor in series to high-pass the Supravox driver at 6 dB/octave. It looks like I want an inductor in the 15-18 mH range for this nominal 6-ohm driver.

Question: Would the iron-core 18 AWG inductors Madisound sells be good for this application? Anything better?
[I realize some will suggest an active or line-level solution but I dislike them both. I find that an inductor at the speaker level has far less an effect on the signal.]

Finally, who else out there is running the Supravox (or Fertin) driver on such a baffle? Honestly, it is really amazing how good these things are.

PaulFolbrecht · « **Reply #1 on:** 30 Mar 2009, 12:09 am »

Of course I'd be looking for a cap to high-pass the drivers, not a coil! Duh! As you can tell, it's been awhile since I've played with xovers. (Somebody on AA pointed this out.)

Good news is that I put 15 hours of break-in time yesterday & today as well as lifted them 2" off the floor (was already planning on doing that). Serious improvement - to the point where the bass is both nicely balanced, and low enough that I am wondering whether I even want to bother with the subs!

Got some very sweet sound in front of me right now already.

dewar · « **Reply #2 on:** 30 Mar 2009, 02:04 pm »

Hi Paul.

I just acquired some new fullrange ob drivers that had too much bass 200-300hz, but managed to flatten it nicely by trimming down the baffles from 60 to 44cm wide.

Have also fixed a similar problem before by using a sub, and just insuring the sub and the mains are out of phase over the frequencies that need to be brought down, very useful attenuation that you can see moving up and down the RTA graph as you twirl the phase knob on the sub.

cheers
B

mcgsxr · « **Reply #3 on:** 30 Mar 2009, 02:35 pm »

Cool, thanks for sharing Paul.

I have not had the pleasure of hearing any field coil drivers, but it seems that I should at some point!

nicksgem10s · « **Reply #4 on:** 31 Mar 2009, 01:27 am »

Hello Paul,

Do you have any photos posted of your speaker setup?

The JE Labs pictures I have seen online have the driver mounted close to the ground on a pretty wide panel.

I was just curious to know if there are different variations.

I have two speakers that utilize custom Supravox 135lb drivers. One is a two way commercial offering and the other is just a very basic simple open baffle that I built using the custom 135lb.

I would love the opportunity to hear the 215-2000 sometime. Do these come in more than one version? I know some Supravox drivers do come in different configurations.

Are you feeling the need to add a ribbon or supertweeter for the top end?

Thanks for posting your experience.

-Nick

Telstar · « **Reply #5 on:** 31 Mar 2009, 06:03 pm »

Quote from: nicksgem10s on 31 Mar 2009, 01:27 am

I would love the opportunity to hear the 215-2000 sometime. Do these come in more than one version? I know some Supravox drivers do come in different configurations.

There are four versions, the standard 215-2000, the 215-2000 OB and the 215-EXC, and the 215-EXC OB.
The OBs are newer and optimized for open baffle setups. The 215-EXC OB would be my fullranger of choice... if i could afford it.

Arlo · « **Reply #6 on:** 31 Mar 2009, 11:03 pm »

Um, yea. Buy me some of these. Kthnkx.

PaulFolbrecht · « **Reply #7 on:** 1 Apr 2009, 02:15 am »

There is only one type of "JE Labs" and it's what you've seen: wide and squat. Dimensions like a Quad!

I won't take pics yet because things are in flux. You can find shots of the JEL baffles all over.

I do have the 215-2000 EXC OB version. I had the non-OB version last time I had these drivers and I think these are better (for OB), though some say there is little difference.

I have been experimenting with lifting them off the floor, as Gerry over on AA does. With 8" bricks as stands the bass has evened out and the mids gained clarity. They are now truly superb. About 50 hours of time on them.

They might be fairly pricey at about $2600/pair, but add $30 of wood and you have a world-class speaker system! There are not many systems of such quality for that money, for sure.

PaulFolbrecht · « **Reply #8 on:** 1 Apr 2009, 06:07 pm »

Quote from: PaulFolbrecht on 1 Apr 2009, 02:15 am

I do have the 215-2000 EXC OB version. I had the non-OB version last time I had these drivers and I think these are better (for OB), though some say there is little difference.

Correction: according to the manufacturer of the completed speaker system I had (last time), the 215s WERE the OB version.

I recall being somewhat confused about that question at the time, when someone asked, only because they just said "215-2000 EXC" (I think).

Last time I had the drivers and put them on the JE Labs baffle, I loved them - which is why I bought the 2nd pair recently! However, last time I never tried the stands - this makes them even better, cleaning up the mids, and bringing the somewhat prominent bass down, as I said.

If someone does have the 'non-OB' version - again, apparently there is very little difference between the two (I don't know what), and the difference can be eradicated by running the non-OB version at a slightly lower coil voltage (1-2V less).

FullRangeMan · « **Reply #9 on:** 9 Apr 2009, 03:30 pm »

Dear FR fans:
Please take care with Field Coil Drivers. I know a friend that have a FR Coil driver that just work fine cold or warm, when the Coil heat the sound quality go away.
But he lives in a hot area.

So open the your eyes or ears.
Regards, Full

JoshK · « **Reply #10 on:** 9 Apr 2009, 05:22 pm »

I only heard the Fertin FC driver. This was OB, with and without helper woofers (4 15"s also OB, indepently powered). This was in a reasonably large room with 45 SET amps. They sounded divine with simple music but gave up the ghost with complex music (woofers didn't help). This could have been the SET amps, but I believe it was more the drivers. Just not enough xmax and I don't think he was hipassing the drivers.

The Supravoxs have much more xmax I believe, I'd love to hear them OB.

I'm also really curious how they would do in a Basszilla style speaker with a ribbon up top and a pro audio woofer supporting the bass. I think that would be a very interesting project.

PaulFolbrecht · « **Reply #11 on:** 11 Apr 2009, 04:50 am »

Quote from: FULLRANGEMAN on 9 Apr 2009, 03:30 pm

Dear FR fans:
Please take care with Field Coil Drivers. I know a friend that have a FR Coil driver that just work fine cold or warm, when the Coil heat the sound quality go away.
But he lives in a hot area. So open the your eyes or ears.
Regards, Full

Heat is absolutely not a problem for these drivers. I leave the coils powered at all times, at 6V, and they never get more than very slightly warm.

PaulFolbrecht · « **Reply #12 on:** 11 Apr 2009, 04:53 am »

Quote from: JoshK on 9 Apr 2009, 05:22 pm

I only heard the Fertin FC driver. This was OB, with and without helper woofers (4 15"s also OB, indepently powered). This was in a reasonably large room with 45 SET amps. They sounded divine with simple music but gave up the ghost with complex music (woofers didn't help). This could have been the SET amps, but I believe it was more the drivers. Just not enough xmax and I don't think he was hipassing the drivers.

The Supravoxs have much more xmax I believe, I'd love to hear them OB.

I'm also really curious how they would do in a Basszilla style speaker with a ribbon up top and a pro audio woofer supporting the bass. I think that would be a very interesting project.

Never heard the Fertins but I've also heard they don't do well on complex stuff. The SV drivers really have no such issues at least up to moderate volumes (85 dB in a large room).

JoshK · « **Reply #13 on:** 11 Apr 2009, 06:53 pm »

Good to know. I've been curious about these drivers for a long while. I am just biased against SD speakers because of my penchant for complex music and moderately high volumes. I would however, love to hear them run as extended mids in something like the Basszilla format.

smccull · « **Reply #14 on:** 12 Apr 2009, 11:03 am »

Paul,

As you know I have the 2000-215 EXC non OB drivers on a JE Labs baffle. Very, very nice! I have a relatively small room and am not getting excess bass, but they are strong all the way down to 60 hz, at least. Maybe lower into the 50s, need to measure them. All in all they are very balanced on this very simple design. I like a speaker I can complete in a weekend!

My only complaint is the occiasional issue with imaging, which may be as much about my narrow room and their narrow placement as anything. When sounds are clearly between the speakers they float in midair well behind the panels, which is very nice. But when the are more localized to the individual speaker they seem to come from more in front, while other sounds are further back in the soundstage. This doesn't happen very often, so it's a minor quibble.

I am thinking of adding a ribbon tweeter crossed with just a cap only for a simple first order xo for the highest frequencies. I feel the SV's need a little more sparkle, but I'm not really missing the lowest bass. I suppose I'm only missing the lowest octave.

Does anyone have any suggestions on a tweeter, and on position on the baffle? I'm thinking ribbon.

levinsje · « **Reply #15 on:** 12 Apr 2009, 04:13 pm »

I have Supravox 215 Exc field coil drivers in open baffle and use a Fountek ribbon supertweeter crossed over with a single silver oil M-cap at 10Khz. I have the supertweeter rotated horizontally instead of vertical as it sounds better that way. I also use two 15" Hawthorne Augie woofers per channel in open baffle crossed over at 70 Hz and below (2nd order active crossover).

To my ears this works very well.

Jim

smccull · « **Reply #16 on:** 27 Apr 2009, 02:08 pm »

Which Founteks are you using with your Supravox's?

levinsje · « **Reply #17 on:** 4 May 2009, 04:16 pm »

I am using the Fountek NeoCd3.0MS 3" Ribbon Tweeter.
You can buy it at Madisound for $89.00 each.
http://www.madisound.com/catalog/product_info.php?cPath=45_229_236&products_id=8359

I Installed mine horizontally instead of vertically as it sounded better that way.

Jim

-Richard- · « **Reply #18 on:** 8 May 2009, 10:15 pm »

Hi levinsje/Jim ~

Do you have a picture of your baffles that you could share with us? I would love to see your implementation/design.

I am considering adding just a bit of sparkle to the top... without the hot "emphasis"... it is really "space" that interests me, not "more" high frequency information.

Thanks for sharing information with us, Jim.

Warmest Regards ~ Richard

levinsje · « **Reply #19 on:** 11 May 2009, 10:55 pm »

Hi Richard,
Below are links to my setup.
I crossed over the supertweeter at 10,000 Hz using an M-cap silver oil.
http://i39.tinypic.com/2hgbl29.jpg
http://i41.tinypic.com/am6weo.jpg
http://i40.tinypic.com/2mo2kx5.jpg

Best Regards,
Jim