Hey everyone!
I have an old focal speaker that I would like to rebuild the crossover with some higher quality components.
Attached are two pictures front and back
C1 - 3.3J 250V
C2 - 6.8J 250V
C3 - 18uF 63V
C4 - 33uF 63V
R1 - 7R1/7W (7.1 ohms / 7 Watts)
R2 - 10R/10W (10 ohms / 10 Watts)
R3 - 1R8/10W (1.8 Ohms / 10 Watts)
L1 - Unknown, need to test with multimeter
L2 - Unknown, need to test with multimeter
L3 - Unknown, need to test with multimeter
L4 - Unknown, need to test with multimeter
L5 - Unknown, need to test with multimeter
I have an old focal speaker that I would like to rebuild the crossover with some higher quality components.
Attached are two pictures front and back
C1 - 3.3J 250V
C2 - 6.8J 250V
C3 - 18uF 63V
C4 - 33uF 63V
R1 - 7R1/7W (7.1 ohms / 7 Watts)
R2 - 10R/10W (10 ohms / 10 Watts)
R3 - 1R8/10W (1.8 Ohms / 10 Watts)
L1 - Unknown, need to test with multimeter
L2 - Unknown, need to test with multimeter
L3 - Unknown, need to test with multimeter
L4 - Unknown, need to test with multimeter
L5 - Unknown, need to test with multimeter
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
adding resistors in parallel reduces resistance. Adding in series adds it, but also increases inductance (still typically quite small) and puts undo load on the higher value resistor. I wouldn't recommend this, just use the right value.
The electrolytic caps can be changed to film, but they will be huge, and may have a negligible effect on sound. They are probably in the woofer lowpass filter, and thus in parallel.
I know you won't probably do this, but I had a whole writeup on my rebuild of some focal speakers. An Electra Center and L-R speakers, and my rebuild found the greatest improvement by redesigning the crossover. Numerous measurements were taken of the individual drivers as well as the entire system both in a room and free space, as well as a lot of modeling. The final result was the largest single improvement I could have made. While changing the parts with better ones may make a difference, it's in the last .1% type change, where as changing the crossover was much more substantial. I fear you will invest a lot of money into upgrading parts only to find the improvement minimal if audible at all.
The electrolytic caps can be changed to film, but they will be huge, and may have a negligible effect on sound. They are probably in the woofer lowpass filter, and thus in parallel.
I know you won't probably do this, but I had a whole writeup on my rebuild of some focal speakers. An Electra Center and L-R speakers, and my rebuild found the greatest improvement by redesigning the crossover. Numerous measurements were taken of the individual drivers as well as the entire system both in a room and free space, as well as a lot of modeling. The final result was the largest single improvement I could have made. While changing the parts with better ones may make a difference, it's in the last .1% type change, where as changing the crossover was much more substantial. I fear you will invest a lot of money into upgrading parts only to find the improvement minimal if audible at all.
What is the model of the loudspeaker ?
I don't think the benefit will be audible. I never listen to a resistance.
You can add brace to rigidify and some bituminous pad inside the box.
The best you can do is to redesign the crossover but you need tools and a high skill level. But I think your Focal should be a "good design".
It's sometimes useless to improve a loudspeaker because the driver are not enough good.
In my opinion, it's better and less expensive to build a better design with a better box, better drivers and a better crossover design.
But if you want to do it for your pleasure , why not ?
Yes you can but you can use simple MKT or MKP capacitors. You will have a problem of space, the components are bigger. Try to find smaller components.
soundengine355 said:
I don't think the benefit will be audible. I never listen to a resistance.
You can add brace to rigidify and some bituminous pad inside the box.
The best you can do is to redesign the crossover but you need tools and a high skill level. But I think your Focal should be a "good design".
It's sometimes useless to improve a loudspeaker because the driver are not enough good.
In my opinion, it's better and less expensive to build a better design with a better box, better drivers and a better crossover design.
But if you want to do it for your pleasure , why not ?
I am not sure which model of Focal you have, but if it was built in the last ten years it probably has the TC90 tweeter in it, in some variant. The aluminum and Kevlar variants are, IMO, all the worse. This is not a great tweeter, and is the weakest link in the system. After having numerous DIYers and manufactuers tell me to switch to the TC120tdx or td5 tweeter, or TLR if I could get them, I finally listened and bought a pair of TD5's which needed to be rebuilt. The DIY designs I had based on those tweeters were, in my opinion, better in every way. They sounded cleaner, more effortless, and most importantly, had a very realistic soundstage.
One of my less pressing summer projects is to finish a set of tower speakers I had started, but interrupted with my Gedlee Summa Abbey build. Since I have the finished cabinets, and just need to paint them, install the drivers, and finish the crossover, I will likely attempt to finish them this summer. This build uses a 6" w-cone midrange, TC120tdx tweeter, and two 7" Mpyre long excursion midbass drivers. None the less, for my needs, I've largely abandoned my Focal speakers. Probably close to ten years now of a love hate relationship coming to a close.
One of my less pressing summer projects is to finish a set of tower speakers I had started, but interrupted with my Gedlee Summa Abbey build. Since I have the finished cabinets, and just need to paint them, install the drivers, and finish the crossover, I will likely attempt to finish them this summer. This build uses a 6" w-cone midrange, TC120tdx tweeter, and two 7" Mpyre long excursion midbass drivers. None the less, for my needs, I've largely abandoned my Focal speakers. Probably close to ten years now of a love hate relationship coming to a close.
Another idea I wanted to do was:
Each speaker currently there is only one pair of binding posts and I would like to Bi-Amp the speakers, so I was thinking of removing the crossover and putting some RCA connectors on the input and two outputs.
Then having my receiver pre-out to the crossover, then it will be split into two and allow the HF and MF to goto seperate channels for amplification and then directly to the speaker driver.
Picture attached.
Receiver -> crossover -> amp -> drivers
Would this work?
Obviously it will need to be done for each speaker taking up a total of 4 channels on the amplifier.
Each speaker currently there is only one pair of binding posts and I would like to Bi-Amp the speakers, so I was thinking of removing the crossover and putting some RCA connectors on the input and two outputs.
Then having my receiver pre-out to the crossover, then it will be split into two and allow the HF and MF to goto seperate channels for amplification and then directly to the speaker driver.
Picture attached.
Receiver -> crossover -> amp -> drivers
An externally hosted image should be here but it was not working when we last tested it.
Would this work?
Obviously it will need to be done for each speaker taking up a total of 4 channels on the amplifier.
Focal Electra 1007be bookshelfs, ok it's a 2 way high end . Don't touch anything, the crossover is well done !
Change the speaker by a bigger or add two subwoofers.
Have you a good amplifier and a good source to obtain the better of this speaker ?
Bi amp active why not ? but a little complicated, you need tools to do it.
Change the speaker by a bigger or add two subwoofers.
Have you a good amplifier and a good source to obtain the better of this speaker ?
Bi amp active why not ? but a little complicated, you need tools to do it.
ah well, thats a bit different. I'm surprised (I shouldn't be) that the Be line is using such a crossover. I know the Be tweeter is considerably more expensive to produce, but have heard that they "cheapened" it in the electra line to keep the price reasonable. While I had a pair for audition, I never took measurements, and have never handled the Be tweeter in person. I'd love to see how it compares to the older Ti or aluminum tweeters. I know some devotees claim to still prefer the TC120's and better TLR's, but it may just be sour grapes. Some day, if I stumble across a set of the Be tweeters, I may buy them to see.
None the less, I still stand by my claim that improvements will be most beneficial from a better crossover rather than from parts improvement.
If I was to pick any one thing to fix that might stand the chance of having the single largest effect from parts quality alone, it would be to replace the series caps in the tweeter circuit with better quality ones as well as the wirewound resistors with either a MOX or better wirewound (mills). Inductors could make quite a difference in the tweeter circuit, but I found that measured advantages of CFAC were biggest for the tweeters (the inductance curve was a bit better through the high frequencies, flatter impedance, lower measured distortion), but would not be easily retrofitted to your crossover. Plus, the improvements I did find were at frequencies that I think most people would argue can't effect the crossover's sound.
As for biamping, I'm not sold on it's merits, as has been said by many of those who really truely know, there are things that passive crossovers can do for which an active crossover can not. While from an acoustic standpoint modern DSP can correct for the audible effects of these things, in many cases, it's easier and better to simply due them in the crossover. I feel that the best solutions involve a hybrid approach where certain characteristics of the response are dealt with passively, while others may benefit from the improved efficiency of the active system. Which doesn't take away from the need to do this right, and I don't believe most people can or do. It must be handled with careful measurements and models to ensure a good response. It's not as simple as simply finding some crossover point that approximates what was originally used and doing this actively.
Having said all that, what is it you want to improve? Is this just one of those, "I want to make it sound better, not sure what specifically." type adventures? Is there a particular quality you are trying to improve?
Not sure what you have for room acoustics, but I bet that would net larger improvements than this venture.
None the less, I still stand by my claim that improvements will be most beneficial from a better crossover rather than from parts improvement.
If I was to pick any one thing to fix that might stand the chance of having the single largest effect from parts quality alone, it would be to replace the series caps in the tweeter circuit with better quality ones as well as the wirewound resistors with either a MOX or better wirewound (mills). Inductors could make quite a difference in the tweeter circuit, but I found that measured advantages of CFAC were biggest for the tweeters (the inductance curve was a bit better through the high frequencies, flatter impedance, lower measured distortion), but would not be easily retrofitted to your crossover. Plus, the improvements I did find were at frequencies that I think most people would argue can't effect the crossover's sound.
As for biamping, I'm not sold on it's merits, as has been said by many of those who really truely know, there are things that passive crossovers can do for which an active crossover can not. While from an acoustic standpoint modern DSP can correct for the audible effects of these things, in many cases, it's easier and better to simply due them in the crossover. I feel that the best solutions involve a hybrid approach where certain characteristics of the response are dealt with passively, while others may benefit from the improved efficiency of the active system. Which doesn't take away from the need to do this right, and I don't believe most people can or do. It must be handled with careful measurements and models to ensure a good response. It's not as simple as simply finding some crossover point that approximates what was originally used and doing this actively.
Having said all that, what is it you want to improve? Is this just one of those, "I want to make it sound better, not sure what specifically." type adventures? Is there a particular quality you are trying to improve?
Not sure what you have for room acoustics, but I bet that would net larger improvements than this venture.
I would really like to get the crossover split into two, HF and MF.
Just need to workout the layout, what connects to what.
Anyone able to help from the pictures?
Also in speaking with Troels Gravesen, he says putting the crossover network between the pre and amp is not a good idea becuase the crossover is meant to look into ~4-8 ohms impedances, not the 10-50 kiloohms the power amp presumably runs.
Just need to workout the layout, what connects to what.
Anyone able to help from the pictures?
Also in speaking with Troels Gravesen, he says putting the crossover network between the pre and amp is not a good idea becuase the crossover is meant to look into ~4-8 ohms impedances, not the 10-50 kiloohms the power amp presumably runs.
Those are no doubt fine components, even the cheap looking resistors
Maybe only C3 and C4 could be poly
I would try to ad small zobel on tweeter
If you have too much highend, you could change the tweeter pad a bit
But dont rip the xo apart
If you want something else, then try and build that, but leave the original xo as it is
Splitting the tweeter and woofer xo in two wont make any difference, and neither will biamp
You can only do that with active xo
And you will need EQ as well
Maybe a room EQ would make you happy
Maybe only C3 and C4 could be poly
I would try to ad small zobel on tweeter
If you have too much highend, you could change the tweeter pad a bit
But dont rip the xo apart
If you want something else, then try and build that, but leave the original xo as it is
Splitting the tweeter and woofer xo in two wont make any difference, and neither will biamp
You can only do that with active xo
And you will need EQ as well
Maybe a room EQ would make you happy
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.