2. misc-audio
  3. 166577-121242

Millercarbon's Mega Moab Mod Meander

One of the all time great automotive engineers, Norbert Singer, was a key player in every one of the 16 Porsche LeMans victories from 1970 to 1998. His dominance was such that at one point Porsche had won LeMans more than all other marques combined. This was all accomplished by building on the already solid foundation of Porsche production models. The air cooled flat 12 in the 917 was really two flat sixes combined to make 12. This car so dominated motorsport the rules had to be changed to stop it!  

So Norbert Singer modified Porsche production technology to extract the absolute most for racing. His legacy is today’s Singer Vehicle Design https://singervehicledesign.com Norbert doesn’t make for a very good car name so they called it Singer. What is a Singer? It is a modified Porsche. It is in essence a hot rod. What Norbert Singer did was make the most hot rod racing Porsche. What Singer does is take that to the next level, capturing every aspect of Porsche right down to excellence of design and aesthetics.  

I am not anywhere near the level of Singer. But that is the spirit of what we are doing: taking an already world-class design and hot-rodding it to be even better. Well, better for me anyway- or so we hope!

The early modders started with substituting off the shelf parts to get more power or less weight. That is pretty much all we are doing here. Would be cool if some day people are doing this with a lot more sophisticated approach. Maybe they will. Maybe even I will. For now though we have the current crossover project.

My approach is pretty simple: better parts sound better.  

This lesson was learned back in the late 90’s with Linaeum Model 10 speakers. The designer had a new tweeter and told me how to modify the crossover for it. Simple mod, one cap, one resistor. Bought the parts from Radio Shack, put it together, sounded like crap. Absolute horrid crap! Called him up, he said those parts are crap. Said Musicap, Vishay. But they measure the same? Just do it. I did. It worked. Even though they measure exactly the same, the sound difference is off the charts.  

Even though they measure exactly the same. There is a lesson here. For those willing to learn.

So this is the essence of it: Eric Alexander has made a speaker the equivalent of a Porsche 911. Even better: an affordable Porsche 911! But after a while with my 911, after learning what makes it drive and feel the way it does, it was only natural to change the shocks and torsion bar and other items to bring out even more of what I like so much about the 911.  

That is what we are doing here. Hot-rodding a speaker. Thank you Rick for the metaphor!  

The parts are on order. Next week the fun begins!
128x128millercarbon
petg60
1,486 posts
 
MC i always liked the idea of upgrading some of the crossover parts in my Dunlavys. I know they can sound even better. It was after reading of all the difficulties a member here in Agon faced till making them sound right again with a good number of changes, especially with absolute coil values, the idea has stalled for now. Looks like the easiest part to do is to upgrade all the wirewound resistors first and pray for some rain. Some of the capacitors later. One step at a time.
Really interested to hear how your project turns out.


glupson
7,842 posts
 
"Really interested to hear how your project turns out.

Is there anybody who does not already know the result?

(Better than Wilson. Any Wilson.)
millercarbon's avatar
millercarbon OP
12,531 posts
 
MC i always liked the idea of upgrading some of the crossover parts in my Dunlavys. I know they can sound even better. It was after reading of all the difficulties a member here in Agon faced till making them sound right again with a good number of changes, especially with absolute coil values, the idea has stalled for now. Looks like the easiest part to do is to upgrade all the wirewound resistors first and pray for some rain. Some of the capacitors later. One step at a time.
Really interested to hear how your project turns out.

Resistors are probably the safest ones to start with. A resistor however you must remember to think of as a fixed volume control. Swap out a resistor of a little higher or lower value and it will have the effect of turning the volume up or down a little bit on whatever drivers it feeds.

But that is not all a resistor does. Resistors also generate heat. Power resistors in crossover networks especially. Heat if you know your basic electronics increases resistance. Therefore a resistor is also going to compress dynamics.

Think about it. Music is nothing but swinging dynamic voltages. Every one of these voltage peaks we want to come through loud and clear. But the increase in voltage produces heat increasing resistance. This all happens incredibly fast and local. Gradually over time the whole resistor will grow warm. But the immediate local effect is for that localized heat spike to increase resistance, turn the volume down, and there goes your dynamics.

All my 15W resistors are being replaced with 2 Path Audio resistors for 20W. These resistors are physically a lot bigger. Instead of one resistor hot glued to a board there will be two vibration isolation mounted with air flow all around. This will greatly increase power handling and heat dissipation. Hard to see how this can be anything but good for dynamics.

But again, remember it is a fixed volume control. It affects frequency response. So if you are sensitive and this is a priority you may notice whatever tiny amount it shifts dB and so to avoid this take care to measure and precisely match values.

I never did this with the Linaeum. I simply soldered in the values the designer told me to use. Never actually measured them to see what the actual values really were. Went by whatever was on the label. Worked just fine. Based on that I am not too worried. Professional driver. Closed course. Do not try this at home. Your mileage may vary.

The information here in this discussion represents hours of searching around talking to experienced modders, picking their brains, combining with my own experience and distilling it all down. I find over and over again that while it is a lot of work, when you take the time to do this you rarely put a foot wrong.

We will see.
nmmusicman
276 posts
 
@millercarbon,

Excellent to hear about folks being curious about modding the crossovers in their speakers. I am good friends with a very prominent speaker designer whose had several very successful speaker companies and he has shared a few secrets with me about what makes a great crossover designs, some of which I can’t reveal for obvious reasons.

I have replaced the mid/tweet caps in one of my speakers from Mundorf EVO to Mundorf Silver/Gold oil and the results were not subtle at all! What was already a high resolution speaker became a liquid see through panorama with greater dynamic reserves and tonal density. This crossover is all point to point wiring with the leads of the components used to make the connections, inductors arranged in space and in relation to each other to mitigate interaction and shock mounted to minimize cabinet/woofer vibration infiltration. Each driver gets its own separate network arranged in space to minimize interaction again. 

One misconception I’ve heard and read about is that shunt component quality in a crossover don’t matter which is not true. Looking at the voltage signal it swings both positive and negative and this involves the shunt components as well. Being curious as I am, I replaced a shunt cap in a woofer circuit from a cheap elecrolytic 68uf 10v cap to a Mundorf EVO 68uf 450V cap and while the results were not as dramatic as those with the silver/gold oil caps in the mid/tweet circuits, it was certainly noticeable which surprisingly extended up into the mid and treble frequencies.

My next adventures are in high end resistors at some point.

Cheers


millercarbon's avatar
millercarbon OP
12,531 posts
 
nmmusicman,

Good to hear. We are on the same page. Already planning everything you mentioned. In fact I just got notice most of my stuff is to be delivered tomorrow. With parts in hand will begin the process of building all the little doo-dads that will hold things in place.    

Here is the plan (so far, I keep improving it as new information arises!):

The new crossover will be all Path Audio resistors. These will be isolation mounted above the board with air space all around.

The cheap electrolytic is upgraded to Jantzen Premium ELKO with a Jantzen Alumen Zcap bypass cap. All the other caps are Jantzen Alumen Zcap with Duelund JDM Silver bypass caps.

All inductors are 12ga Goertz Alpha Core. They will be mounted as you said, arranged to mitigate field interactions.

All components will be mounted with as much attention to vibration control as I can muster. Every component will be treated appropriately with fO.q tape, as well as some other stuff I have that I’m not supposed to talk about.

The original was all hand soldered direct component to component and I hope to be able to achieve that here as well.

The "board" will actually be a PPS Omega Mat bonded to a BDR Shelf. This will be threaded to attach Townshend Pods. The whole thing will then be reinstalled inside the speaker on the same brace, which will be reinforced and enlarged to accommodate the now much larger crossover.

What was already a high resolution speaker became a liquid see through panorama with greater dynamic reserves and tonal density.

Exactly what I am going for. Exactly what others who have done things like this talk about. So glad you posted this. So when it actually happens it will not be out of the blue.

What I like is you got this result from just the caps. I am doing at least as big a cap upgrade, plus a big inductor upgrade, plus a huge resistor upgrade, plus a huge vibration control upgrade- and with better magnetic field management. Whew! If after all that it ain’t a holographic fantasmagorical experience I will be sorely disappointed!
More to discover