Problem Solvers Needed-Got my New XOs installed and am worried....


I think I made a big mistake. I loved the sound of my 1988 Tannoy FSM Dual concentric 15'
speakers. So I thought an expert could analyze the existing XOs and make improvements.
I installed the new XOs expecting a 300-400 hour burn in period. Herein lies the problem.

After 30 hours or so the initial sound has no high end to it. I expected to initially hear sound as good as I had
which would continue to improve as the burn in continued. But no. 

I am tempted to reinstall the old XO and kiss off the $2k invested. 

I am very open to some suggestions from anyone who has been down this road.

Thanks,
chorus

Showing 1 response by erik_squires

So, about upgrading XOs...

Yes, if you are doing a part swap, then keep the original values. However! DCR in coils and ESR in caps must be maintained, especially in those devices which go to ground, often via a resistor. If you can’t measure that, but only know the uH or uF you are in danger of altering the design. Reducing the DCR or ESR of a part can significantly alter the sound and not for the better. These values are taken into account at design time.

You can’t substitute a generic crossover for a previous crossover. The electro-mechanical properties of the speaker and drivers function as a unit.

There are times when a speaker’s crossover justifies a complete rethink. I’ve seen this in some Focal and Genesis speakers where impedance drops really did justify a reworking here. I’ve also seen actual speaker designer Troels Gravesen post some really interesting write ups on vintage B&W and Yamaha speakers as well. Go take a look there if you want to know how actual speaker designers think about crossovers:


http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm


You should be well versed in speaker analysis and crossover design before you attempt this, and even then you must ask yourself, if I’m rethinking this crossover shouldn’t I just build new?

And then... well, if you are building new... lots of outstanding kits out there, not to mention speaker drivers waiting to be assembled into a dream setup.

As always, I encourage DIY and learning about speaker making.  Please do so! Just don't assume things are simpler than they are. :)