5 way project - tapped, bass, mids and tweeter, big boy system

[Pano]

Great work, thanks for posting it! It's so nice to see someone build something, rather than just discussing it. Especially something this big and complex.

There are some fairly simple mods you can do to the DCX to make it sound much better. I've modded a few, and it's a very crossover nice with a little work.

BTW, a number of your photos are now missing in action. Can we fix that?

[Speedysteve7]

Great to hear more DCX usage views - I've read most of the thread on here about it all. The flexibility and functionality of the unit is as you say very good.

Yep - Webshots finally died and has gone to Smile, which is not free and is as far as it will not offer a photo hosting / sharing facility. so useless for me.
Never fear I've got all the photos into Photobucket now, so can recreate a few pages at a time - other work load depending...

The first thing I will mod is bypassing the op amps - 4.7uF coupling caps straight from the DAC output connector to the outputs, 47K or perhaps higher resistor to ground. That will get me 2.4V out instead of the current massive amount - my poweramps can return to the normal input settings and hopefully quality will increase.

Soon after I hope to have me hands on the DSP project DCX

I've not looked at ADC side - probably a lot more difficult / beyond me.

I ran the Tapped horn un time aligned for a good while - It crosses at 90Hz on 48dB/oct slope and is Antimode DSP'd adding a further delay of 3ms.
So around 10ms all up - assuming 7ms delay but perhaps it is as high as 9.
It all seems so much better time aligned - I should do some tests on just tapped and bass horn listening, with / without to verify the effect.

The 2496 DCX handles it perfectly. Checking the alignment once DCX'd the first peak positive of the tapped horn and bass horn coincide perfectly.

[Pano]

Originally Posted by Speedysteve7

Never fear I've got all the photos into Photobucket now, so can recreate a few pages at a time - other work load depending...

If you contact me via PM, I can help get the photos back in, and this time hosted here on the forum, so they'll stay around.

The ADC isn't hard. I just built a nice opamp circuit to go from unbalanced to balanced and provide the low impedance that the ADC wants. Used the DCX +/-15V rails with local decoupling. Works like a charm, sounds great.

For the outputs simply route the DAC outputs to 1:1 line transformers, then on to the amps. Also works great. Replacing the cheap electrolytic caps on the DSP board also worked wonders. I just did the 5V supplies near the DAC chips and near the regulator. Used 100uF/25V Panasonic FM series, IIRC. Whatever is the largest value of the Panny FM that is in the same size package as the original caps. Easy switch. A much more dynamic sound as a result. A pleasant surprise!

[Speedysteve7]

Ah yes the edit func. disappears on this forum - forgot that...

Wow those mods seem beyond me. I have more basic electronic abilities.

Small steps

Originally Posted by Pano

If you contact me via PM, I can help get the photos back in, and this time hosted here on the forum, so they'll stay around.

The ADC isn't hard. I just built a nice opamp circuit to go from unbalanced to balanced and provide the low impedance that the ADC wants. Used the DCX +/-15V rails with local decoupling. Works like a charm, sounds great.

For the outputs simply route the DAC outputs to 1:1 line transformers, then on to the amps. Also works great. Replacing the cheap electrolytic caps on the DSP board also worked wonders. I just did the 5V supplies near the DAC chips and near the regulator. Used 100uF/25V Panasonic FM series, IIRC. Whatever is the largest value of the Panny FM that is in the same size package as the original caps. Easy switch. A much more dynamic sound as a result. A pleasant surprise!

[Speedysteve7]

Last night I finished off the 1st Behringer DCX mod. As per passive output stage for Behringer DCX2496

This shows all the components that Behringer though
Double checked all and then fired it up on the Tapped and bass - can't damage them with much as they are Eminence Kappa 15" 650W Pro drivers...

Always sounds weird with just bass and weirder still with just one channel playing.
Then I fedd the other drivers in carefully and bingo - we have a 5 way mono.
Was not sure about the sound at first. But seemed to improve - caps getting used to working perhaps?!
A lot less gain so my power amps could be set pretty much as I had them before the DCX malachy

Anyway - cracked on with the other one for the other side. Having done one side the 2nd was quick and easy...

Stereo pair sounded more normal and all working. Setting the power amps at the reference of pretty much exactly what I had them at with the passives gave a nice balance of the driver vols.
I am so used to changing the different levels after tweaks and honing in, I do it by ear and prefer it to what measures flattest.

The more I played and tested the more I liked what I hear - always have to be careful that your ear adjusts and fools you. Obviously can't hot switch this mod

Some nice improvements to detail and clarity of instruments and vocals we clearly discernible - bit unsure of the bass, need to test that more this evening...

[Speedysteve7]

Over Christmas I have been testing further and swapped back to the passives.
I do prefer the passives though. There is more clarity, detail and punch in mid, upper and tweeter. Even the bass is clearer but not as well defined as with the active steeper slopes (if that backs sense).

My latest madness is a pair of Vitavox S2's. One is near mint and has been reconditioned recently by Vitavox. The other is completely missing its diaphragm. That will be going back to Vitavox in the new year for clean, recharge and new diaphragm.

Then I will have S2's to play with.
Here is one measured against a JBL2435Be on the same 600Hz horn (note crossovers are in place)

The S2 is in red and the 2435Be in green.



Measurements only tell you so much - As I have learned with BMS4296 and JBL2482 drivers that measure very, very similarly - tone is something else that can't be so easily measured.
After that I am thinking of a round Hyperbolic or Exponential bass horn to match the others. This will most probably be a laminated birch ply rings affair and cut on a basic horn lathe I will make.

Cut something like this.
Azurahorn -Le Cleac'h Acoustic Horns - DIY Manafacture

Other news - I invested in a further EL84 SET amp for the Raal Lazy Ribbon tweeters.
Much nicer sound over the T-amp. I needed to make a wider shelf. Bit of birch ply and med oak coloured wax did the job.

[Speedysteve7]

Today's fun will be identifying more photos for Pano to fix the broken links on this thread when Webshots turned off.
Nice work by Pano fixing the first page some of the 31 pics!


Plus I hope to get time today / tomorrow to break out the Tapped horn and bass horn passive components into separate boxes. The 5 way crossover boxes just sort of grew and whist I was smart in inducter placement, there may be some gains to be had from separating them further. The do interfere with each other, esp the big ones I guess and I have some 30mH ones in there!
I do pace them rotated / flipped to each other, if that makes sense.

Another reason is placement can be better and it's more flexible cabling wise.

[Speedysteve7]

The passive re-housing is done. In the end I only needed to re-house the 4th order rig for the tapped horns. Once these were out of the way there was plenty of room for the other 4 relatively puny size of the other 4 way components - 24mH inductors / 316uF caps + 12mH inductors / 70uF caps + Zobel. That lot all takes up quite a space.

New dedicated boxes made for the tapped horn passives.

So does it sound any different - No not really, at least not on first casual listening... Perhaps some more bass complex stuff will reveal more.

I will now go back to the Behringer x 2 DSP DCX to see how I feel about this solution.
I am trying to keep an open mind, I am trying to keep an open mind

[Speedysteve7]

So after over an hour of listening to Behringer 2496 DCX here are my thoughts.

Without any DSP time or phase correction (all are aligned apart from the tapped horn using Holmimpulse), and all the slopes and X/O points set to the same as the passives, it sounds quite similar to the analogue.
It has remarkably similar properties in terms of sound signature and overall characteristics.

BUT and there is a big but, it is about 80-90% of the resolution of the passives. Imagine a high res picture or TV picture in very good clarity and sharpness, then look at a lower res picture, pixelated or that shimmer you get. That is what the sound diff is like in visual terms.
The DCX fails to resolve with clarity, anywhere on the frequency range. Quite clear when you just listen to a single pair of drivers. Even more obvious LH to RH comparisons of a mono signal. I would be able to pick out the DCX every time I believe.

Cymbals are a bit of a disaster, the DCX just makes a poor attempt at them, splashy and not realistic or convincing. Gone is the shimming Raal fineness.
As soon as the music gets complex, it gets messy. Makes me want to go for the next calmer, less difficult to resolve track.

Me, I'm going back to the passives... and will await the DIY DSP DCX and see what that holds.

[jordheis]

Hi,
Good choice moving to a sound that you enjoy. Cymbals that shimmer is a goodness!

I understand waiting out the DIY DSP DCX solution as well. In the meantime, consider the points Pano brought up earlier. A little more modding may result in >90% resolution of the passive solution. Doesn't look like a costly or difficult mod. I am sure someone could help if you are not comfortable with the task.

PANO wrote;
"Replacing the cheap electrolytic caps on the DSP board also worked wonders. I just did the 5V supplies near the DAC chips and near the regulator. Used 100uF/25V Panasonic FM series, IIRC. Whatever is the largest value of the Panny FM that is in the same size package as the original caps. Easy switch. A much more dynamic sound as a result. A pleasant surprise!"

Love this thread!