Modifying Crossovers

@jaytor  +1 on the ceiling panels!

I have only read the OP's post and will comment on their inquiry.

As an example there is a Speaker Designer Troels Graveson (TG), who offers the Schematics/ Parts/ Cabinet Dimensions using a selection of Brands products for his own Speaker Designs. 

The general consensus in the community that uses these designs, is that a Basic Speaker Design, that can cost between $3000-$7000 to produce if done correctly as a DIY Build, can easily compete in the arena with Commercial Products costing 6x - 10x the Build cost of a TG Design.

In many cases TG offers a Xover Upgrade for these designs, that can add another $500+ to the above build cost. It does seem the utilisation of the Upgrade, produces a coherence in the SQ and gathers the presentation to where it can be perceived as more honest and believable. It does not necessarily mean the measurements produced for the Speaker or the Speakers impact on Room Modes are going to change. 

Note: All that is produced Upstream of the Speaker Xover is Signal not Sound. All that is produced downstream of the Xover is Sound, and it is the perceived quality of the Sound being produced that has the attraction/detraction element, during a system in use evaluation.    

My advisory to an individual with the confidence in their skills and wanting to attempt to attain a improvement to the SQ produced from a Speaker by swapping out Xover components is to work with the Internal Wiring as the initial investigation. Changing Internal Wires can have an impact on the perceived SQ that impresses. It is also one of the most cost effective measures to utilise to increase the experience of what can be attained. When a Internal Cabinet Wire is discovered that meets with ones attraction, this can also be considered for use externally as a Speaker Wire, the unknown is how the Connections at Amp' and Cabinet can have, as a detrimental effect can occur, leaving anticipated expectations not quite met.

If one is really bold, not too concerned for the convenience of using connectors and are in possession of End Game Amps and Speakers that are out of a Warranty period. There is the Option to Wire from the Amp's Internal to the Xover bypassing  connectors. As a option it is easily undoable and returned to the original build method.

It does not take long when using the Web Sites that have assessed numerous Cap's for their influence on a sound, that when the most rated ones are costed for , there is a outlay fast approaching a $1000+. That becomes a lot of money and burn in hours to learn if such a change to the Xover has been valuable for the SQ.  

Yep. My lowly B&W 802 series 3 were probably built in 97' when I discovered Troels Gravenson speaker building designs,I was stoked when he does a crossover upgrade for these speakers. I couldn't buy the kit fast enough, talk about a fun project. Most rewarding project I've ever done. I'm gonna tear into them again one day and replace these parts with even better Jantzen parts and silver wire. I could've easily asked Jantzen for his better products and wish I would've.

A diy speaker project is in the works also. 

@carlsbad2, with regard to the Duelund bypass caps, I'm curious to know if you listened to your system before installing the bypass and what change you heard after, also which ones did you chose?

@jaytor, very nice set up you have there and I notice in the photo you provided of your XO that you too appear to use Duelund bypass caps. As there are a variety of Duelunds caps I'm asking because I wish to buy once and cry once 🙂

@lemonhaze - 

I'm using the Dueland 0.01uF JDM Tinned Copper Foil Bypass caps on both the tweeter series cap and the midrange shunt caps, I didn't really notice much if any difference on the midrange caps, but they added a touch of sparkle and airiness in the tweeter circuit. 

I added these before the crossover caps were burned in though, so I'm not sure if they would have had the same affect after burn-in. But I'm really happy with the way my speakers are sounding now so don't want to make any changes.