Big Blue

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10-17-2006, 10:13 AM
John W

2 Attachment(s)

Big Blue

Here are the plans I have in the works for building a big 4-way system. The design has basically evolved from a desire to put a set of accumulated drivers and parts to good use, and try out Jack’s axially symmetric oblate spheroid CD waveguides.

Initially I was considering building a separate “dog box” for the top 3 drivers and then playing around with a couple different options for the lower bass. In the end I decided to build just a big box, rather than 2 or three separate boxes per side. The footprint is about the same either way, and the current design worked out to be the most economical use of materials.
1 – 5x5 sheet of Baltic Birch
2 – 4x8 sheets of 1in MDF
1 – 4x10 sheet of walnut veneer
With separate boxes I couldn’t come up with a way to provide the same volume, have the boxes veneered and stay on budget.

The drivers I have are:
18in 2241G woofers up to 290hz
12in 2202H midrange driver running from 290hz to 1.2khz,
2in 2445 using the same profile horn described in your initial post from 1.2khz to 10khz,
and a 2403 cats eye from 10khz up.

Also, I still have a pair of AB international tri-amp amplifiers to drive them. The amplifiers put out 850w@4 ohms for the woofers, and have two more 250w channels per side. They are currently set up with an internal crossover it 400hz and 1200hz, with some various low frequency boost options. Eventually I would like to try a digital 3-way crossover, but this may have to wait. To accommodate the tri-amp design I decided to implement a passive crossover between the mid-range horn and tweeter. This was pulled from the 4355 crossover, with an added 20uf cap up front of the mid-range as dc and thump protection.

From my calculations the box will end up about 8 cubic feet after subtracting volume for the dog box and drivers. WinISD suggests a 35hz tuning for the 2241G. I plan on making the ports easy to replace in case I end up swapping out the woofers for 2245s or something else later and have to re-tune the box.

Construction has already begun. The turned horns are finished and I’ve started on the cabinets. Let me know if I need to put the brakes on, otherwise I’m trudging ahead and will keep you posted.
10-17-2006, 10:40 AM
Earl K

1 Attachment(s)

Quote:

Originally Posted by JohnW

Construction has already begun. The turned horns are finished and I’ve started on the cabinets. Let me know if I need to put the brakes on, otherwise I’m trudging ahead and will keep you posted.

Hmmmmm,,,, John ,

- Only because I have such great respect for your wood-working abilities , do I suggest something a lot more ambitious,( both sonically and build-wise ) .
- The ***sonic purity of a round horn*** just begs to be used with an MTM type system .

- How about something like this kludge-up ? It's an asymmetrical, MTM-based, "fanciful-thought" project ( for the time being ) .
- It's meant to be a biamped / triamped ( only ) system ( just for the sake of simplicity ).
- The 2245H and 2206 ( or other qualifying 12" ) are run paralleled, with various means applied to restrict/blend their respective response curves.
- ( ie; the 18" "working" in a ported cabinet would have a large inductor on it to roll down its midrange ( earlier than the 12" ) / while the 12" working in a "largish" sealed doghouse slowly rolls out its' LF response ).

- You'd need to sell your 2202 midrangers ( I know, I know this is all a stretch ;) ) and obtain midwoofers instead, like the 2206H, to make this sort of MTM concept workable .
- The midwoofer ( 2206H ? ) should be located as close to the horn as possible / with a center to center spacing ( 2245 to 2206 ) of around 34" as a reasonable goal.
- Another ( perhaps conflicting ) design goal is to use a ( large enough ) round horn that will support a crossover point as low as 600 to 650 hz ( with minimal low-mid "correction" EQ ) .
- Whatever 12" midbass woofer is used , it needs to have a similar efficiency to that of the 2245H. It also needs to offer pretty linear output ( from @ 80/100 hz to 650 hz ) when housed in its' sealed ( @ )1 cu' subenclosure. For Xmax reasons, a long coil winding depth ( > than or = to .75" ) offers the best compromise for this job description . ( Aquaplassed cone, a deeper gap, higher compliance surround and higher BL factors are also desirable attributes / though much tougher to obtain through eBay type purchases ) . The ME120H or 1200Fe do come to mind as my first choice twelves to explore ( when designing with specs. from a page / and when referenced through my own hands-on experience with the ME150H ) .

- I believe you'll need to design & build a small round waveguide for your 2403 driver to maximize the imaging capabilites of a 4way system . This will most likely entail copying the initial "compression-chamber" of the 2404 tweeter to achieve the correct, initial compression characteristic necessary for a bit of diffraction.

- The original image belongs to "pantaNS" and is of his 4-way system that uses a 2245H and a 2206H ( among other things ).

:)

Okay , not yet ? maybe in a couple of years. ;)
10-17-2006, 11:25 AM
John W

I like your idea. Alas, maybe next time.
10-17-2006, 02:13 PM
jack_bouska

Quote:

Originally Posted by John W

Here are the plans I have in the works for building a big 4-way system. From my calculations the box will end up about 8 cubic feet after subtracting volume for the dog box and drivers. WinISD suggests a 35hz tuning for the 2241G. I plan on making the ports easy to replace in case I end up swapping out the woofers for 2245s or something else later and have to re-tune the box.

Construction has already begun. The turned horns are finished and I’ve started on the cabinets. Let me know if I need to put the brakes on, otherwise I’m trudging ahead and will keep you posted.

John
The cad drawing looks interesting, some quick thoughts in no particular order:

- If you have a digital camera, post a photo or two of the horns

- How do you plan to mount the 2245 on the horn? (They are heavy!)

- remember, the 2445 will not have flat freq. Resp on the waveguide, so you will need to do lots of xover horn eq mods to get it to sound right.

- I have not run the simulations, but if I remember correctly, the 2241 has a higher Fs compared to a 2245 (35Hz vs 20Hz?). If you have eq capability in the amps, then consider tuning lower and using judicious boost after testing Freq Resp n your room

- lastly (and you might hate me for this), what about turning the speakers 90deg, and mounting the 2202, 2445 and 2403 on the skinny 18” wide side of the cabinet, leaving the 2241 on the wide 28” side. This would make the original front the side, and the side into the front. You would have enough room to put the three drivers in line vertically on the skinny side (the 18” wouldn’t be in the way anymore) and the narrow dimension would cause fewer frequency response and imaging problems due to the diffraction effect caused by the wide cabinet. You can place the drivers closer to one side than the other, depending on internal bracing, etc.

The 18” does not need to face forward, as ½ wavelength at 290 Hz (2') is around the size of the cabinet, so the 2241 is pretty much omni directional below the xover, so it doesn’t matter which way it faces.

Keep us posted
Jack Bouska
10-17-2006, 03:43 PM
John W

1 Attachment(s)

Thanks Jack,
I'll post some pictures of the horns tonight.

- The drivers bolt directly onto the base of the horns, which should be pretty evident when you see the pictures. They are quite heavy, which causes me some concern. Within the larger cabinet they will just clear the top of the inner box housing the 2022 drivers. My plan is to securely brace the 2445s to the top of this box using some sort of cradle and strap, and hopefully prevent them from putting too much strain on the horns.

- I plan on a little roughness in the response on these drivers, taming it will have to follow getting them put together.

- The speakers are going to be pretty large. I hear your concerns about baffle diffraction and driver placement, but I think turning the speakers sideways would bring them too far out into the room to be practical. The boxes will be mirror imaged in keeping with the design of other JBL monitors, like the 4344 and 4345. The 4345s are similar in size and they image quite well. From what I’ve read elsewhere there are advantages to having a horizontal alignment of upper midrange and tweeter, both at ear height, especially since the tweeter designs tend to have a narrower vertical beam width.

- I’ve modeled the 2241 drivers in WinISD and played around with a few different box tunings. The picture below shows three tunings: the green at 35hz the orange at 30hz and the grey at 27hz. I guess I don’t see the advantage to lowering the tuning too much?
10-17-2006, 04:00 PM
John W

Behringer DCX2496

I have been looking at the Behringer dcx2496 digital crossover for this project. Does anyone have any experience with it?
Does it offer any equalization functions or is it strictly a crossover?
10-17-2006, 04:00 PM
Robh3606

Quote:

The boxes will be mirror imaged in keeping with the design of other JBL monitors, like the 4344 and 4345. The 4345s are similar in size and they image quite well. From what I’ve read elsewhere there are advantages to having a horizontal alignment of upper midrange and tweeter, both at ear height, especially since the tweeter designs tend to have a narrower vertical beam width.

Hello John

The 4344's do image well and there is an advantage because of the very narrow vertical dispertion of both the higher you go.

Quote:

I’ve modeled the 2241 drivers in WinISD and played around with a few different box tunings. The picture below shows three tunings: the green at 35hz the orange at 30hz and the grey at 27hz. I guess I don’t see the advantage to lowering the tuning too much?

Well that depends on how they work out in your room. I have my XPL clones tuned low and with room gain they come in just right. You have to be careful, you don't want to end up with the last 2 octaves all jacked up so leave yorself some room so you can try different tunings to see what works best and what you like.

I agree with Jack on a narrow profile baffle would be prefereable or have seperate boxes but it's hard to get the volume you need in anything other than the shape you have chosen. Those 18's need a good amount of room to breath. Have Fun!!! We want pictures!!!!

Rob:)
10-17-2006, 04:27 PM
Titanium Dome

Quote:

Originally Posted by jack_bouska

(snip)- lastly (and you might hate me for this), what about turning the speakers 90deg, and mounting the 2202, 2445 and 2403 on the skinny 18” wide side of the cabinet, leaving the 2241 on the wide 28” side. This would make the original front the side, and the side into the front. You would have enough room to put the three drivers in line vertically on the skinny side (the 18” wouldn’t be in the way anymore) and the narrow dimension would cause fewer frequency response and imaging problems due to the diffraction effect caused by the wide cabinet. You can place the drivers closer to one side than the other, depending on internal bracing, etc.

Jack Bouska

I was surprised and pleased to see this recommendation. (But then you're by no means a traditionalist. ;) )
10-17-2006, 05:26 PM
Don Mascali

Behringer DCX 2496

IMHO, DON'T.
On paper and in use this is an amazing piece of gear for "Home" use. BUT, I have owned three of them and every one has the habit of making an intermittent "Sizzling Bacon" sound when I think it looses a ground due to piss poor construction or some other reason beyond my capacity to under stand. I guess when you steal someone elses design and built it cheaply you miss a few things. It does have PEQ, Limiter, Auto Time Alignment/Phase setup among other functions.

Zilch has one now, maybe he can shine some light here.

I ended up with a YAMAHA D2040 4 way digital that sounds good. It has no where near the bells and whistles as the DCX 2496 but is clean and solidly built.
10-17-2006, 05:37 PM
John W

3 Attachment(s)

Here are some pictures of the walnut horns.
I glued them up with 1 7/8 hole running down the middle to make turning easier.
My lathe is older than dirt, but it runs smooth and is quite solid.
I plan on mounting them from the back with some screws on the outside baffle edge.
These are currently unfinished. I will apply the finish when doing the cabinets.
10-18-2006, 04:20 PM
jack_bouska

2 Attachment(s)

[quote=John W]Here are some pictures of the walnut horns.
quote]

Wow, nice looking waveguides, I’m envious, to say the least.
I hope you think they sound as good as they look in the pictures!

Now for some additional quick comments before off to bed:
- I’m not sure the xover circuit shown in post #1 will work all that well with the oblate-tractrix waveguide
- I’m posting a couple of images which show a comparison between the JBL PT waveguide, and 2381 horn against my oblate-tractrix (on a jbl 2441) – all without EQ applied. The oblate-tractrix matches the PT-waveguide frequency response quite closely in overall shape, so if you can find an example of a xover and eq for that waveguide-driver combination, it should be close to what you need for your system.
- Barring that, I might have a few spare moments to cut-and-try some passive xover and EQ later this month. If I get anything to work, I’ll post what I did.
- Passive xovers depend heavily on the impedance of the drivers: What is the nominal impedance rating for your 2202H and 2445?
- let me know and I’ll try some spice simulations.
- in the mean time, I’ll post a first attempt at a 2nd order xover (similar to Wayne Partham Pi-align xover) in an image below.

Best of luck, and let us know how the system turns out when all the sawdust and solder settle

Jack Bouska
10-19-2006, 07:45 AM
John W

2 Attachment(s)

Mr. Widget did a great analysis of the ring radiators in this post:

http://audioheritage.org/vbulletin/s...ead.php?t=6368

Here is a copy of the impedance plot for 077 and 2405 tweeters with a couple different diaphragms. It should be pretty similar for the 2403. I think 10 or 11 ohms is normally used.

I also cut a little plot out of the 2245j sheet. These are 16 ohm versions.
I went with the version shown up top basically because the drivers are similar to those in the 4355 and the crossover calculators I have access to suggested values that were about the same. I am not a crossover expert, so things like baffle compensation and differences in horn response were not really considered. I’m all ears if you have a better suggestion.
11-01-2006, 09:19 PM
John W

4 Attachment(s)

Construction is mostly done, and I thought I'd share some pictures:
11-01-2006, 09:22 PM
John W

2 Attachment(s)

A couple more.
11-01-2006, 09:28 PM
John W

So far listening results are postive.
I listend to the speakers tonight with the active 3-way amps and the passive crossover between the horn and 076. They sound big.
I tuned them as best I could with the little dip switches on the amps that assist in level adjustment, but I don't think I was able to balance them just right. The potential is definitely there.
Next step is to get a digital 3-way crossover and try them with some amps that I am more familiar with.
11-01-2006, 09:56 PM
saeman

Awesome

Hi John: Have been waiting to see what you came up with since you first mentioned the project. They look fantastic and I really like your mid range horn. Please post more pics. How about you move 1000 miles east and I'll move 1000 miles west.

Rick
11-02-2006, 09:19 AM
John W

Thanks Rick,
I'll take a few more shots of the inside and post them soon. I am still trying to figure out the best way to secure the big compression driver.
11-02-2006, 09:33 AM
edgewound

Superb, John....

Stunning work...very impressive.:applaud:
11-02-2006, 09:56 AM
Mr. Widget

Quote:

Originally Posted by John W

Thanks Rick,
I'll take a few more shots of the inside and post them soon. I am still trying to figure out the best way to secure the big compression driver.

Please do... it is always fun to see what you are up to.

I read that Rick was having trouble duplicating the pebble texture on the blue baffles... what are you using to get your texture?

Widget
11-02-2006, 10:03 AM
saeman

Quote:

Originally Posted by Mr. Widget

I read that Rick was having trouble duplicating the pebble texture on the blue baffles... what are you using to get your texture?

Widget

I second that! I 'm coming close using a textured stone type spray and laying the JBL blue over it. Looks great a couple feet away but on close inspection it looks a bit too coarse. John - Your baffles look pretty close. Didn't you say earlier that you thought your finish was soft and not durable ? Let's solve this problem without buying a high dollar splatter spray gun.

Rick:bouncy:
11-02-2006, 10:13 AM
John W

I coated the baffles with a light spray of Homax spray texture from a can using the finest nozzle attachment. This is normally used for interior touchups on drywall.
On this pair I followed up with a spray coating of polyurethane spray, hoping the finish would soak into the plaster-like texture and harden it up. I still don't think it is as tough as I would like.
11-02-2006, 04:38 PM
Earl K

- Gorgeous work John !!! ( as always ! )

:)
11-05-2006, 06:56 PM
Ken Pachkowsky

John

Very nice....

I am planning a trip down to your area to visit friends (used to live in Seattle).

Maybe I will bring an extra Deqx I have sitting here and come over to check your system out? You/we could try the Deqx crossover on it?

Let me know.

Ken
11-05-2006, 07:20 PM
scott fitlin

WOW, really nice work. That horn looks sweet!

Love the pictures of you working the lathe. Incredible, and creative work at its best.

:D
11-06-2006, 08:15 AM
John W

Quote:

Originally Posted by Ken Pachkowsky

Very nice....

I am planning a trip down to your area to visit friends (used to live in Seattle).

Maybe I will bring an extra Deqx I have sitting here and come over to check your system out? You/we could try the Deqx crossover on it?

Let me know.

Ken

Sure thing Ken, that sounds great. I'd love to try a listen on the Deqx.
11-07-2006, 06:14 AM
4313B

Interesting.

Excellent work as usual John. :)
11-07-2006, 07:27 AM
spkrman57

Great looking speaker system!

I like the wood horns also.:)

Those speakers have to sound awesome!;)

Ron
11-07-2006, 08:32 AM
Ken Pachkowsky

Quote:

Originally Posted by John W

Sure thing Ken, that sounds great. I'd love to try a listen on the Deqx.

I will pm you when I have a firm date but it will be soon.

Ken
11-07-2006, 08:43 AM
Woody Banks

OUTSTANDING!

John
Very impressive! I love the horns and the incredible attention to detail throughout. Hell, I thought my lathe was old. Thanks for sharing.:applaud:
Woody
11-07-2006, 08:52 AM
John W

I ordered a Behringer DCX2496 digital crossover yesterday so I can hook these babies up to some amps that I am more familiar with and tune in the response a little better. I’ll have to hold off on a more expensive crossover for now.
When it arrives I plan on using the digital link from the cd player and setting up some sort of 6-way volume control between the crossover and the amps. I don’t know exactly what this will look like just yet, probably 3 stereo analog pots connected with gears and a small chain or something.
Anyone done anything similar?
11-07-2006, 09:38 AM
jack_bouska

3 Attachment(s)

Quote:

Originally Posted by John W

I ordered a Behringer DCX2496 digital crossover yesterday so I can hook these babies up to some amps that I am more familiar with and tune in the response a little better. I’ll have to hold off on a more expensive crossover for now.
When it arrives I plan on using the digital link from the cd player and setting up some sort of 6-way volume control between the crossover and the amps. I don’t know exactly what this will look like just yet, probably 3 stereo analog pots connected with gears and a small chain or something.
Anyone done anything similar?

I built up a 12 gang log pot by dismantling 12 dual potentiometers and re-assembling the pieces so that they all connect together to form a single very long multi-ganged potentiometer. Tracking is reasonable, but not perfect. A six gang version would be better. Buy extra pots, and match the tracks using an ohm meter, then assemble matching carbon tracks as stereo pairs.

I use this beast to adjust the output volume of a pair of DCX2496's, configured as dual 5-way crossovers. See attached images. I don't have the manufacturer make and stock number, but I'll look it up when I get home tonight. - Jack Bouska
11-07-2006, 12:43 PM
scorpio

Selectronic in France does a kit for similar purpose, have a look at:

http://www.selectronic.fr/audiophiles.asp

Caution, it's all in French...

They also have an interesting page on all sorts of other mods for the 2496, including power supply etc...

Sorry, can't write a translation, there's too much info.

Cheers,
11-07-2006, 12:45 PM
scorpio

Blaaah, my mistake, go at the bottom corner of the page I sent the link, they have an international page with an english fact sheet, sorry it's late in the day for me already...:o:
11-08-2006, 06:37 AM
jack_bouska

3 Attachment(s)

volume control options

Quote:

Originally Posted by jack_bouska

I don't have the manufacturer make and stock number, but I'll look it up when I get home tonight. - Jack Bouska

I dug out a sample of one of the dual gang pots that I am using, and had a look at the manufacturers name, they are listed as NMEG (see photo below).

These are fairly expensive, see maplins catalogue:
http://www.maplin.co.uk/Search.aspx?criteria=FX09K&DOY=8m11
However they provide good front to back tracking when ganged together in large lengths.

For a simpler, and less expensive option, try looking for potentiometers which allow adjustment via access at the back of the pot, using either a flat blade screwdriver or hex shaped Allen-key recess. You can then build a six channel volume control by ganging together three stereo pots, by shaping two of the front spindles to fit into the back of the preceding pot. See example in photo below. Front to back tracking is not as good as the nmeg option above, but a little dab of epoxy helps fill the gaps and form a tighter unison.

Another (much more expensive) option is to use switched volume controls, like the CT2 six gang version from DACT http://www.dact.com/html/attenuators.html which will set you back a few hundred dollars (almost as much as the DCX!), so buying a few dollars worth of stereo log pots looks like a much more economical approach.

Jack Bouska
11-08-2006, 08:14 AM
John W

Thanks for the info. This looks like a good solution. I'll check out a couple sources today and see what I can find.
11-13-2006, 05:52 PM
John W

3 Attachment(s)

I got the new Behringer crossover connected up this weekend. Hooking up the speakers through this crossover to a trio of mosfet home-built amps made a big difference in the sound. Much better.
The volume control is three dual pots connected side-by-side with ribbed knobs and belts. I think connecting them front to back would be a better solution, but I didn’t want to wait for mail-order and was able to get work this up from locally available parts.
So far, the crossover is working out quite nicely. The software is fairly intuitive and sound is great. The horns are very natural sounding, but even after equalizing them flat as best I could, I found the 2445s a little harsh. Eventually I swapped in a pair of aluminum diaphragm 2440s which is a big improvement.
Also the initial tuning of the ports was 28hz. This was a little low and boomy for the woofers, so I swapped in a couple shorter ports bringing the tuning up to about 32hz. Anyway, I’m not done tweaking yet.
Here are a couple shots of the setup and the equalizing on the drivers. The response is fairly flat now.
11-14-2006, 07:08 AM
jack_bouska

Quote:

Originally Posted by John W

The horns are very natural sounding, but even after equalizing them flat as best I could, I found the 2445s a little harsh. Eventually I swapped in a pair of aluminum diaphragm 2440s which is a big improvement.
(snip)
Here are a couple shots of the setup and the equalizing on the drivers. The response is fairly flat now.

What's the vertical & horizontal scales on the green RTA display? (Hz and dB/div)

On axis?
how far from the boxes?
how do the curves look off axis?

as mentioned in an earlier post, the 10kHz passive xover to the cat's eye is probably too high and not steep enough to suppress the diaphram breakup on the 2445's. Aluminum has more internal damping compared to titanium, and the 2440 phase plug might also suppress some of the breakup above 10k
11-14-2006, 09:40 AM
John W

The RTA is Behringer too, an 8024 in 1db mode. I think there is an 8db spread vertically between the grid lines.
You can just make out the horizontal scale if you look real close at the picture. Roughly the first 19 bars cover 20hz to 1.25k, the next 10 bars cover the range of the horn 1.2k to 10k, then the last three the tweeter. I think that either the pink noise generator or measurement setup is missing in the tweeter region. I can make adjustments and hear the difference, but can't seem to get the top bars level.

This measurement is taken about 2/3 of the speaker height vertically and about 4 feet from the front, on axis. I also took some measurements from the actual listening position and did a little more tweaking there.
I missed doing the off axis measurements. I'll have to set things up and try that part again.
11-14-2006, 09:52 AM
John W

Quote:

Originally Posted by jack_bouska

as mentioned in an earlier post, the 10kHz passive xover to the cat's eye is probably too high and not steep enough to suppress the diaphram breakup on the 2445's. Aluminum has more internal damping compared to titanium, and the 2440 phase plug might also suppress some of the breakup above 10k

Yes, this could very well be the case.
12-29-2006, 11:14 AM
John W

3 Attachment(s)

I turned a pair of new horns for the big speakers for use with a pair of 1.5 in 2435HPL drivers. After playing around with a few different designs using the Hornresp program I settled on the design below.
http://www.users.bigpond.com/dmcbean/

The program isn’t the most user friendly, and I had to estimate a few of the parameters, still once you learn the basic steps it allows you to easily calculate contours for quite a few types of horns.

I needed the design to fit the existing hole, and terminate flush with edge of the cabinet. The design starts off as an oblate spheroidal contour at 700 hz and transitions into single spherical to angle it around flush.
The sound really nice, very natural and uncolored. The 2435HPL is fantastic, super detail and transparency.
12-29-2006, 11:16 AM
John W

2 Attachment(s)

Here is a plot of the horn response in the cabinet on axis about 3 feet from the mouth, and a plot of the equalized response of the whole speakers.
12-29-2006, 11:32 AM
Robh3606

Very nice John! Glad to see you are enjoying your drivers! Those horns look great!!!

Rob:)
12-29-2006, 12:06 PM
Mr. Widget

Very cool John.... I am once again impressed. Keep up the great work!!

Widget
12-29-2006, 01:34 PM
edgewound

Most impressive

Wow, John.

Your craftsmanship is absolutely first rate.
12-31-2006, 11:35 AM
pangea

Ultradrive DCX246

Quote:

Originally Posted by Don Mascali

IMHO, DON'T.
On paper and in use this is an amazing piece of gear for "Home" use. BUT, I have owned three of them and every one has the habit of making an intermittent "Sizzling Bacon" sound when I think it looses a ground due to piss poor construction or some other reason beyond my capacity to under stand. I guess when you steal someone elses design and built it cheaply you miss a few things. It does have PEQ, Limiter, Auto Time Alignment/Phase setup among other functions.

Zilch has one now, maybe he can shine some light here.

I ended up with a YAMAHA D2040 4 way digital that sounds good. It has no where near the bells and whistles as the DCX 2496 but is clean and solidly built.

I have two of those Ultradrives :banghead: and both of them have that same "Sizzling Bacon" problem, one of them was sent back to Germany but came back with the same problem, so I haven't bothered sending the other one back.

Behringer still pretend there is no problem with them, although I have heard people complain all around the world.

Right now I have a dbx Driverack 260 at home and this one is far better. It even does what the Behringer Ultracurve does, so the extra cost is well spent IMHO.

/Roland
12-31-2006, 03:51 PM
edgewound

Hi John,

Have you considered turning a UHF waveguide for a 2407?

I think that would air out the top end nicely. Just an idea for you.

I love looking at your work:)
12-31-2006, 04:00 PM
John W

Quote:

Originally Posted by edgewound

Hi John,

Have you considered turning a UHF waveguide for a 2407?

I think that would air out the top end nicely. Just an idea for you.

I love looking at your work:)

Thanks Edgewound, what driver would work well for a waveguide tweeter? I haven't had much experience with anything other than the ring radiators.
12-31-2006, 04:10 PM
edgewound

Quote:

Originally Posted by John W

Thanks Edgewound, what driver would work well for a waveguide tweeter? I haven't had much experience with anything other than the ring radiators.

Well, John...

The 2407 is a ring radiator with a mylar diaphragm. Do a search for 2407.

Zilch has done some testing on them and seems very impressed with their extension and transparency....out to 30kHz. 2406 and 2407 are both mylar ring radiators, the 2407 being a very neat, tiny neo mag driver you could hold in your fist. 2406 is a ferrite version.
I have both the 2435 and 2407's. I haven't done actual testing on them, but listening to their respective smoothness with a sweep generator really raised my eyebrows. Best I've heard from JBL...period.

Both have 1 3/8 18TPI thread mount.

I bet you could physically time align them with your 2435's.
01-01-2007, 08:49 PM
Izzy Weird

:applaud: Wow, are those pretty horns or what? :applaud:

I hope someday to hear these speakers. I also really like the traditional JBL monitor look you gave them.

Beautiful !!!
01-02-2007, 09:20 AM
UreiCollector

wow

Impressive craftmanship on the horns!! I'm impressed!:)
01-10-2007, 03:28 AM
spirou38

Quote:

Originally Posted by John W

I ordered a Behringer DCX2496 digital crossover yesterday so I can hook these babies up to some amps that I am more familiar with and tune in the response a little better. I’ll have to hold off on a more expensive crossover for now.
When it arrives I plan on using the digital link from the cd player and setting up some sort of 6-way volume control between the crossover and the amps. I don’t know exactly what this will look like just yet, probably 3 stereo analog pots connected with gears and a small chain or something.
Anyone done anything similar?

Hi John,

Great job :applaud:

The Thierry MARTIN DCS2496 tweaking website ( in french or english ) :

http://www.dcx2496.fr/index.htm

Best regards from France.

Pascal
01-10-2007, 08:51 AM
John W

Thanks for the link.
So far the dcx2496 is working out nicely. I read that one possible cause of the “frying bacon” problem was the output stage circuit board could possibly flex with the tension from the many cables and short out with the bottom of the chassis. After opening up the case this seems quite possible, since there isn’t much clearance.
The one tweak I made was gluing a stiff plastic insulation sheet between the output board and the metal chassis to prevent this from happening. I was a little surprised Behringer hadn’t done it already. I guess only time will tell if this actually prevents anything bad.
01-10-2007, 10:59 AM
Zilch

"Fish paper" is commonly used for the purpose:

http://www.oliner.com/fishpaper.htm

[At the hardware store.... :thmbsup:]
01-10-2007, 11:56 AM
spwal

your speakers are simply gorgeous. i wish i had those kind of wood working skills.
01-10-2007, 12:21 PM
johnaec

Quote:

Originally Posted by John W

So far the dcx2496 is working out nicely. I read that one possible cause of the “frying bacon” problem was the output stage circuit board could possibly flex with the tension from the many cables and short out with the bottom of the chassis.

Check this message: http://srforums.prosoundweb.com/inde...%22#msg_165617

Also, a search for "frying bacon" at that site will turn up TONS of info on this.

John
11-23-2007, 04:36 AM
JBL 4645

“I love the smell of bacon in the morning” :D I especially liked the DIY on the fader device to control the outputs form the DCX2496. Isn’t there any off the shelf multi fader, control units that you can buy at relatively affordable prices?

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