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
rixthetrick's avatar
rixthetrick
1,060 posts
 
@ ricevs - 9AWG (NINE) now that’s an inductor. Thanks for sharing, very cool.
And yes microphonics are a real issue. After mine were wound, I dipped them in a winding varnish that was tested out for it’s sonic characteristics.
Next time will be ribbon inductors, and Path resistors.

When you do your outboard crossovers, do you also run separate speaker cables to each circuit, so as to not share signal or potential from ground?
Run them directly to the output of the amp, my old boss did that on a limited run of outboard crossovers and it worked very well. Of course, he makes ribbon speaker cables, and internal speaker wire, the crossovers have two full runs of 2+" wide ribbon 2.5 metres long. It gets expensive at that point.
willgolf
936 posts
 
A question for MC or anyone...if you had an opportunity to replace the drivers or all of the components you worked on what would you do if money was not an object.  Where do you think the biggest bang for the buck is between the drivers and the caps/ resistors etc?  
nmmusicman
276 posts
 
@millercarbon,

I got a big jump in resolution going from the stock spikes on the outboard crossovers to the Walker Audio Resonance control kit under each crossover. The solidity of each instrument in space is spooky and a real good recording just hangs in the air. Cymbal attacks are heavy and the weight of each cymbal can be clearly heard. Of course, average recordings are just as fun!

https://walkeraudio.com/product/valid-points-resonance-control-kit/
rixthetrick's avatar
rixthetrick
1,060 posts
 
@willgolf - There's a lot of unknowns in swapping out drivers in a loudspeaker. First thing I'd consider is the fact a decent designer is going to choose drivers that compliment each other in a multi driver loudspeaker.
Crossover points, anti-phase, and the resulting frequency response are chosen and then developed after listening based upon the characteristics of the drivers chosen in the concept stage of the speaker design.

Can a driver swap out result in a better sounding loudspeaker, yes, and depending on how well integrated that driver is in the overall design, no, not at all.

There's a few unknowns that affect the final result, cabinet design (volume for one), port design (if it uses porting), impedance and also the response and efficiency of the driver. It can be like playing with a Rubiks cube, you may get one thing better and three things not.

I do know of a speaker designer who can swap out drivers, selecting replacement drivers suitable for the volume of the cabinet, for example, then completely redesign the crossover to suit. This takes a lot of time to do correctly, and you are essentially creating a entirely new loudspeaker, with different crossover points, and change the balance of energies to try and bring the response curve into something coherent.

Researching a replacement driver with very similar measurements and characteristics, could help you find one not requiring changes to the crossover to get a better sound, I'm just saying that simply buying a better driver doesn't mean an increase in performance.

There is a synergy on how multiple driver speakers interact, and the crossover and cabinet are hugely determining factors.
Having measurements of the driver you're wanting to replace, certainly moves you closer to finding a replacement, it's a starting point.
millercarbon's avatar
millercarbon OP
12,531 posts
 
willgolf-
A question for MC or anyone...if you had an opportunity to replace the drivers or all of the components you worked on what would you do if money was not an object.  Where do you think the biggest bang for the buck is between the drivers and the caps/ resistors etc?
 
If money was not an object I would call Eric say build me your SOTA Assault Speakers, stat, only make em all Duelund and Path, designed with outboard crossovers and hang on I will be sending you some stuff to go in there. I would call Max say build Eric some F1wires for internal. I would call Krissy say you want to see Utah? Cuz I am flying you out to paint and stuff just load em up, Quantum those suckers to the next dimension. Oh and then you are going on to Texas where you do the same with Dave, since money is no object he will be building me some sweet Raven mono blocks to be run off the Allegri Reference pre-amp Max will be making. Which you can then fly to the UK to massage, or come do your magic here, your call, just so I get my Krissy magic.

This was a huge bang for the buck. It was however a lot of work. No doubt about it. For less effort but a lot more money all Be drivers would be a no-brainer. But I like Plan A a lot better.
More to discover