Speaker crossover mod. Your advice?

Will do.

Just spoke with Jeff from Sonic Craft. Very knowledgable and very helpful. Here is what he recommended:

1. Tweeter cap C1. Replace with (2) Mundorf s/o in parallel (1.8uF + 1.8uF)

2. Tweeter cap C2. Replace with (1) Mundorf s/o.

3. Tweeter Resistor R1. Replace with Mills MRA-12.

4. Midrange cap C3. Replace with Jupiter Vintage Flatstack + Black Gate AC series in parallel (exact values TBD).

5. Midrange caps C4 & C5. Replace with Sonicaps Gen 1.

6. Bass caps C6 & C7. Replace with Axon or Solen caps.

NO inductor change recommendations? hmmmmmmm.

Correct.

Magfan, of the 3 types of passive components in hi-cuurrent filters, coils have the least sound. Also, their resistance helps determine the Q of the filters. So one could spend a lot of money and time buying new coils with matching inductance and resistance and produce NO audible difference in sonic quality. 'Tis much better to spend that money on higher-quality caps.

He gave me the same advice (but for specifics on tweeter caps) on the filters in my Avanti x-overs, I heeded it, and I'm thrilled with the results.

Bryon, I believe you'll be very happy with your results.
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I have one lingering question regarding the values of the caps for the midrange. Here is how they are labelled on the caps themselves:

MIDRANGE CAPS
C3 = 56µF 63V, bottom right of this pic
C4 = 12µF 63V, bottom left of this pic
C5 = 4.7J 250V, top left of this pic

Notice that C3 and C4 are both SMALLER than C5, yet according to their labels, they are much LARGER values.

I am now wondering if C3, which is marked 56uF, is really a 5.6uF cap. Likewise, I am wondering if C4, which is marked 12uF, is really a 1.2uF cap.

Could C3 and C4 really be 56uF and 12uF and still be much smaller than C5 which is 4.7uF? Or can I infer from their small size that they are really 5.6uF and 1.2uF, even though there are no decimal points on the caps' labels?

I just don't want to order the wrong midrange parts.

Bryon

Voltage is as much a determinant of size as is capacitance. Also, film caps occupy lots more volume per Farad than 'lytics.

Just make sure you read them carefully. 56uF is not unusual in a MR filter; mine had a 33uF 'lytic.
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I made a big post about 'parts ain't parts' and it never made it.

without elaboration:
no part is pure anything. Inductors? have DCR and capacitance.
Caps? ESR and inductance. Caps are even microphonic.:: Clarity link available upon request.

It is possible and not THAT tough to replace a saturable small ga. iron core inductor with an aircore of similar (within say......5%) DCR. My Maggies have an iron core inductor. .4ohms, 16ga. wire. Online calculators? Designed a new inductor of 0.38ohm, using 14ga wire.
IF the minor effect of a change in DCR is of importance than surely the configuration of the inductor must be important, too.

The OP of this thread? The crossover had 7 inductors and they were not optimally placed....mutual inductance, and all.
I'd take this opportunity to go to an external crossover.

Bryon,

The size of the capacitor does not indicate its capacitance. You can get a meter from Sears for about $25 that will let you measure capacitance. That way you can be confident when you place your order.

Byron, Just by looks, I'd say your parts are correctly labeled. A 10mfd Polypropylene is in general about the same size as a 100mfd electrolytic... In general only, different configurations are all different. I have a couple of .47mfd Teflons, they are larger than a 200mfd Electrolytic. The small cap values that you quoted look to be polypropylene, the larger value caps are definately electrolytics. Your coils all look to be reasonable quality, I would not mess with those, it could cause more problems than helping, replacing the electrolytics will make the biggest difference. After that, you will need to spend some money on replacing the Polyprops to make much of a difference. When you make the change, don't be immediately upset if there isn't a huge improvement, caps take time to burn in just like electronics do. Good Luck, Tim

Also, Byron, I just went up and read Jeff's recommendations for sonic craft, he is right on. He is recommending some expensive parts. I am a really cheap mug. I would recommend that you go on flea bay. Do a search for Polystyrene capacitor... you will find some 1.0 mfd russians come up, these are great caps, use a good polyprop 1.0 mfd shy and then use the polystyrene as a bypass, you won't find a better bang for the buck. Like wise do a search for Teflon Capacitor. These two russian caps compete with caps 10x their price. Be aware, these are BIG parts. You might even find some larger value Polystyrenes or Teflons, they do exist, just hard to find.
Good luck, Tim

Jeff/John - I will get a meter to measure the capacitance of the midrange caps before replacing them.

Timlub - Thanks for the recommendations. I will take a look.

And thanks again to everyone for your input. I will report back after I have ordered and installed the parts to let you know how things turn out.

Bryon

Hello Bryon,

I have a Focal 1027 BE spreaker, which is simular to your 1027 S. I like the detailed sound very much, but what I am dissatisfied with, is the midrange. Its to thin and lightweight.
So I am thinking of a modification and found this thread.
I analysed the crossover circuit. It has as your 1027 S, the same layout, board and parts except C1 for the beryllium tweeter section, which has 3.9uF instead of 3.6. The inductors (winding, size) looks very much the same.

Since it is reported by other users, that the sound of the 1027 S is warmer and more filling especially in the midrange, I would like to check, wether the sound can be adapted to the 1027 BE.

Mid and tweeter have on both speakers the same crossover frequency, which is about 2.2 kHz. So this can not be the difference. The used mid chassis in the BE version is Focal 6 W 4361. Can you tell me, which one is build in the 1027 S (top chassis of the speaker)?

Either they used different mid chassis or they modified the inside of the box. Maybe there is no path through below the mid or tweeter to the woofers (closed chamber). Did you make photos from the inside or do you remember how it looks like?

Sorry for my poor english, hope you understand it.

louk

Hi Louk - I have the same speakers that you have, the 1027be.

I'm not sure I understand your question. Are you asking about the crossover, the drivers, or the enclosure?

Bryon

Hi Bryon,

in your first post on top you wrote in the first sentense: "I'm considering modding the crossovers of my Focal 1027s".
So I thought you have the 1027 S version. Then this is a misunderstanding of me. I was questioning for the differences of both (BE and S version) to adapt the midrange design of the 1027 S to the BE. This is supposed to be more present than on the BE and results in a more round and warm sound. But since you have also the BE, you can't answer my question. What a pity.

louk

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)

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

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

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

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

The other midrange was too faint to read as well. Judging from your picture of the rear of your driver, I'd say our midrange drivers are the same. So I don't know what to attribute the difference to.

bc

Hi Bryon,

thanks for your help. In the meanwhile I could get in contact with someone of the Focal service. He told me, that the mid drives of the S and BE are the same but the casing box construction and the crossover board differs. The S is softer tuned. The S doesn't have the beryllium tweeter.

louk

Hi Bryon, have you got pictures of your finished crossover to share? Thx

I hate to break the news to you BUT the best crossovers is NO crossovers AT ALL ! Crossovers just degrade the sound !

Hi Hifisoundguy,
Go ahead and get some Focal 1027's, remove the crossovers and let me know how it goes.

Hifisoundguy... By that you mean a single "full range" driver.

Sorry to rain on your parade, but full range drivers have a mechanical crossover due to cone breakup. The dust cap and innermost portion of the cone are the tweeter. Such a mechanical filter is difficult to design, hard to manufacture consistently, and prone to wear-out change.

Hi Bryon,

have some new infos for the 1027 BE fans. Last week I added the Yamaha RX-V2067 AV Receiver to the equipment and used the YPAO calibration function. It complained, that the phase of the 1027 would be wrong connected, but this was not the case. So I asked my self, why does the software report this error. Since I had made fotos of the crossoverboard from front and back sides incl. the wiring I took a look at it. And what surprise, the minus pol of the input terminal is connected to all drivers plus pol except the mid driver. In my opinion, this is the reason, why voices do sound thin and wider than usally experinced.
The YPAO SW is able to calibrate reflection and frequency and so, does equalize this unusual turns in phase.
Since your fotos do show the same crossover board with the same wiring, this is not a factory fault. That is the way focal want let the LS sound, but as reported doesn't satisfy me fully.
I turned the polarity at the input terminals and calibrated again. The error diappeared. Voices are now more in forground and not so thin, the sound not so bright and not unnaturally wide.
The RX-V2067 did neutralize bassmodes of the room and made slight modifications to the frequency response, to have it more linear. With this setup I am now very happy with the focal 1027 BE.
Would be intereseted to here, if anyone experienced the same or could retrace it.

Best Regards

Hi Byron, what was the result of the cap replacement in these speakers? interested to know your results

Thanks
Kris