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Speaker crossover mod. Your advice?

I'm considering modding the crossovers of my Focal 1027s. Specifically, I am thinking about replacing the capacitor associated with the tweeter. I have received some helpful advice from another A'gon member who has done a similar mod to his crossovers (on a different model speaker from the same manufacturer).

I would greatly appreciate any suggestions from folks who have experience with this sort of thing. In particular, what sort of improvements can be achieved with this kind of mod? Any thoughts on which caps to use? Any common mistakes I should avoid? Is the whole thing a bad idea?

Thanks for your input.

Bryon
bryoncunningham
rodman99999
6,036 posts
 
I haven't read all the posts, so- someone may have already mentioned the sonic benefits of observing the directionality of film caps. Most of the better ones are marked, in some way, as to which lead is connected to the outer foil. Good tips, especially(in your case) point three, here: (http://www.audience-av.com/capacitors/a_applications.php)
bryoncunningham OP
890 posts
 
Louk - The "s" in the first sentence of my post was simply meant to be plural, as in "my Focal ten twenty sevens." I had forgotten that Focal made a speaker designated 1027S. Sorry for the confusion.

In any case, I do indeed have the 1027be, and I can say that I don't have the same problem in the midrange that you are describing. I don't doubt what you are hearing, but I wonder if there's an issue elsewhere in the system. I have found that the 1027be is rather revealing of issues in upstream components.

Bryon
xlouk
6 posts
 
Hi Bryon,

before I got the 1027 BE I did have the Trent II from Castle, a wonderful sounding little loudspeaker combined with an Infinity subwoofer. Not that perfect as the Focal but not so far of it. For the price, absolute high value. If I compare the 1027 BE with the Trent II and with other loudspeaker, the midrange is to thin. Also my ear is missing some pressure in the mid (voices and some instruments). Clearly it may also be a matter of taste, but I don't beleave, that it is only that. Maybe they changed something in the series. Which midrange chassis is built in your BE (my is as stated 6 W 4361)? The serial number of my BE is 10A 000 115, but there is nowhere a date of production.
One point but very unlikely could be, that the mid chassis has a lost of efficiency. Electrically I could not find a problem. I did wobble the voltage at the mid with a tone generator and checked the wave with an oscilloscope. Below 2kHz it gets a maximum of 80% amplitude of the crossover input. The impedance of the mid is 7 Ohm, I expected 8 Ohm, but I have to verify that with a better multimeter.

louk
bryoncunningham OP
890 posts
 
Louk - The serial number is 10E005493.

Which midrange chassis is built in your BE (my is as stated 6 W 4361)?

By "midrange chassis," do you mean the midrange driver? If so, I'm not sure what its designation is. I looked at the back of the driver and the information was so faint that it was unreadable. Here is a photo of the midrange driver:

midrange driver.

bc
xlouk
6 posts
 
Hi Bryon,

yes, midrange driver. Here is a photo of mine: http://img855.imageshack.us/img855/4416/mid6w4361back1.jpg.
If you like, you may look on the second mid driver, whether the label is there better readable.
I would assume, that your 1027 BE was later produced an may have been improved a bit. On the crossover C1 changed from 3.9uF to 3.6 on your board.

louk
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