Speaker Analysis for Armchair Critics


Hello everyone,
There’s a very important discipline called "Speaker Analysis" or "Speaker Testing" which though complicated, is brilliantly illustrated in this breakdown of the B&W 685.


http://www.audioexcite.com/?page_id=6070

Speaker analysis is to measure each of the components both separately and as they come together in a complete system. It is a part of creating a new loudspeaker, but it can also be used to analyze an existing speaker, to understand it and perhaps to make it better.  I prefer the term Analysis because it better reflects that the goal is not merely quality assurance, but to build a complete electro acoustical understanding of the system as a whole so changes can be considered, and their final results predicted.


This particular article does just that, and comes up with a couple of suggestions for re-working the crossover to end up with hopefully a better end result. At the very least, it is a significantly different speaker at the end, and achieves a far greater level of change than cables can.


I share this with all of you just as an example of the work that goes into making a loudspeaker from parts, and the tools, and how much of what we hear has to do with choices made in the crossover.


Best,

Erik
erik_squires
I think these particular speakers are a real good example of how disjoint the driver development can be vs. the crossover and system.
I did not read the article but everything is usually built to a price point so the possibility of improving the B&W cross-over is not out of the question.  Very few manufacturers use the top line capacitors, resistors, wire, etc.  I have been repairing audio components with my partner for a long tome now.  There are so many ways to swap out some parts to improve the sound in many areas.  I recently repaired an old Counterpoint power amp that had both the Plitron transformer and Plitron choke upgrades.  At the same time I had the same amp without those upgrades in stock form and another amp with just the Plitron transformer.  Being a comparison person, I was able to listen to each and get handle if there were any improvements. So now I know what each prat contributes.  So the B&W X-over could be improved IMO.

I was recently at an Audio Society where I met the owner and speaker designer of Genesis.  The amount of time, research and development he went through to make the current line was incredible.  Over $3 million spent.  I learned so much I never imagined. He also spent time researching and understanding the recording and playback processes for vinyl.  He brought along different vinyl recording to demonstrate the process.  I was amazed at what I heard and what I learned.

So I take everything as a learning process that can only help me develop a better system for me.  I also don't always believe that speakers are the cause of brightness, or bass issues.  To me the causes is what is feeding them.  For example I placed one of my power amp designs recently on Thiel speakers.  Everything improved.  Installed my DHT DAC and the sound was even better, last my preamplifier and I have to say that now I realize the potential of Thiel speakers were before I mostly read that they were bright sounding.

So IMO don't take what you read of advise you receive for granted, there is something to learn from each and everyone of us.

Happy Listening.
Boy I disliked the old B&W speakers with those ugly yellow kevlar cones. I’m thinking of speakers like the CDM1, a perfect example of a speaker that sounds exactly like it looks - tweeter frequencies sounding detached and too bright. Yuck.
@avanti1960

The diy community has a very different take on what a great loudspeaker should sound like compared to mag reviewers.

As I have said more than once, the high end sound has been driven by king makers to something very far from neutral and for old ears.

Kill the Buddha (reviewer) and find your own nirvana.
"... for consumers, this is a decent introduction, not a comprehensive guide."

It is a FAR MORE THAN DECENT introduction!

The process I use is pretty much what the author did. Once the first iteration is built, even if the measurements look good, I use my ears to tell me whether it’s "right" or not. And if not, then I gather data to figure out what isn’t right, which in turn points me towards what to do about it.

Duke

Duke @audiokinesis

You are killing me.

😆😆😆


I meant to say that "the goal of speaker analysis is..." 

and for consumers, this is a decent introduction, not a comprehensive guide.


I agree with the direction of all of the changes the author made. I probably would have reduced the output of the tweeter in the crossover region even more that he did, to partially offset its excess off-axis energy at the bottom end of its passband.
Yes. B&W must have made a silly mistake and overlooked that. 
the big thing I took away was how honest the reviewer was about the sound.  you NEVER see this in "pro" or online amateur reviews.  
Erik wrote: " I share this with all of you just as an example of the work that goes into making a loudspeaker from parts, and the tools, and how much of what we hear has to do with choices made in the crossover. "

Your post and that article are a welcome respite from repeated accusations by one person on this forum of being a scammer because I’m a loudspeaker designer. Thank you Erik.

"... the goal is not merely quality assurance, but to build a complete electro acoustical understanding of the system as a whole so changes can be considered, and their final results predicted."

Imo a complete acoustic understanding would include a great deal more off-axis data. This is just my opinion.

" This particular article does just that, and comes up with a couple of suggestions for re-working the crossover to end up with hopefully a better end result. "

I agree with the direction of all of the changes the author made. I probably would have reduced the output of the tweeter in the crossover region even more that he did, to partially offset its excess off-axis energy at the bottom end of its passband.

Duke
This particular article does just that, and comes up with a couple of suggestions for re-working the crossover to end up with hopefully a better end result.


What gives him the ability to do better than B&W could do? Are you suggesting B&W dont understand how to do crossovers?

Its all a matter of opinion in the end. There is no such thing as a better crossover, only one that is tuned to your ears. 

I would suggest that 6db with 4khz notch is hardly optimum.