maxhifi
Addicted Member
It looks like there is probably just a nonpolar electrolytic capacitor blocking bass from the satellite speakers. This fixed 125Hz frequency is probably based on 8 ohm speakers being connected.
Rogers LS3/5A subwoofer diy dilemma
- Thread starter Andresse
- Start date
-
- Tags
- rogers ls3/5a
It looks like there is probably just a nonpolar electrolytic capacitor blocking bass from the satellite speakers. This fixed 125Hz frequency is probably based on 8 ohm speakers being connected.
Yes, I looked up the specs too and your explanation sounds quite plausible.
maxhifi
Addicted Member
This isn't something you'd likely find in a higher end stereo application, because routing the signal though the plate amp will at least theoretically degrade it somewhat, and require longer than optimal interconnects or speaker cables. An electronic crossover would be the ticket here, either that or a separate rack mount sub amp with built in crossover.
This might work:
https://meniscus.lightningbasehoste...he-Kairos-and-Continuum-Three-Way-Writeup.pdf
http://techtalk.parts-express.com/f...e-kairos-and-continuum-three-way-loudspeakers
I'd probably choose different woofers but, his are proven designs.
https://meniscus.lightningbasehoste...he-Kairos-and-Continuum-Three-Way-Writeup.pdf
http://techtalk.parts-express.com/f...e-kairos-and-continuum-three-way-loudspeakers
I'd probably choose different woofers but, his are proven designs.
Last edited:
The OP has some KEF drivers already that he wants to use.
Basically, in my opinion, the OP needs to design a passive subwoofer from scratch with the design based around the drivers he has, and the design has to mate seamlessly with LS3/5as . Not a trivial task.
A friend's design based on the KEF 104:
https://sites.google.com/view/mpbs-ls35a-project/kef-104-woofer-for-ls35as
https://sites.google.com/view/mpbs-ls35a-project/kef-104-woofer-for-ls35as
bimasta
Addicted Member
I'm a great believer in using what I have at hand — in boxes, closets, the garage. I already paid for them (not much, all were bargains) and they're all good — like OP, I have drivers and xovers from KEF, JBL, B&W et al.
I used the first few weeks of the Covid lockdown to make 2 pairs of speakers, very different in design, at negligible added cost.
But if the KEF drivers OP already has aren't right for the job, he'll just waste time, energy and frustration. The subs Pete B's friend made definitely look like they'd do the job, and depart radically from the AB1 design, which they must. But "for Pete's sake", what a ton of work!!! OP would need a great workshop, great tools, and most of all great skills.
As stated, I made 2 pairs of speakers, but nothing nearly as ambitious as those subs; it's one reason I opted for open baffle. I don't have great tools or any kind of workshop: I made mine in a spare room with hand tools.
If OP can duplicate those subs, do it!
I used the first few weeks of the Covid lockdown to make 2 pairs of speakers, very different in design, at negligible added cost.
But if the KEF drivers OP already has aren't right for the job, he'll just waste time, energy and frustration. The subs Pete B's friend made definitely look like they'd do the job, and depart radically from the AB1 design, which they must. But "for Pete's sake", what a ton of work!!! OP would need a great workshop, great tools, and most of all great skills.
As stated, I made 2 pairs of speakers, but nothing nearly as ambitious as those subs; it's one reason I opted for open baffle. I don't have great tools or any kind of workshop: I made mine in a spare room with hand tools.
If OP can duplicate those subs, do it!
Hello everybody. Sorry for my English.
Even if I'm pretty late, I'd add some ideas.
I have a pair of home made LS3/5a, and I'm going to make a pair of Kef Reference 101 replica.
I also have a pair of B139 woofers, and I will build a pair of subs to add to above mentioned Kef satellites
This woofer has been used by Kef in several designs. Two of them are in my opinion interesting: Concerto and Cantata. Concerto adopted a 60 litres bass reflex box, Cantata a also 60 litres sealed box. Both of them have a very good lower extension, with F3=35 Hz. I would build a more modern shaped cabinet, higher and, as much as possible, slim, with the elliptical driver mounted in vertical way, allowing a width around 27-28 cm. for a 60 litres volume. I would use the reflex tuning of Concerto, with the possibility of a sealing cap to switch to closed working configuration.
Still to be decided is the crossover. The best solution would be an electronic crossover, and two separate amps for sub and satellite. The active crossover allows a easily variable frequency and relative level adjustment.
As alternative a passive crossover shall be deigned and built. The Kef Cantata has a 250Hz cut between B139 and B110, and it's possible to replicate this section of the crossover.
Other examples are avalable. Unfortunately, no flexibility to choose different schematics unless spending a lot of money in experimentation.
In both cases, active and passive designs, the advantage compared with sub modules or commercial subwoofers is the high pass filtering of satellites, giving higher power capability than full range use of them.
Thanks for the attention, and for the opinion somebody may add.
Regards
Roberto
Even if I'm pretty late, I'd add some ideas.
I have a pair of home made LS3/5a, and I'm going to make a pair of Kef Reference 101 replica.
I also have a pair of B139 woofers, and I will build a pair of subs to add to above mentioned Kef satellites
This woofer has been used by Kef in several designs. Two of them are in my opinion interesting: Concerto and Cantata. Concerto adopted a 60 litres bass reflex box, Cantata a also 60 litres sealed box. Both of them have a very good lower extension, with F3=35 Hz. I would build a more modern shaped cabinet, higher and, as much as possible, slim, with the elliptical driver mounted in vertical way, allowing a width around 27-28 cm. for a 60 litres volume. I would use the reflex tuning of Concerto, with the possibility of a sealing cap to switch to closed working configuration.
Still to be decided is the crossover. The best solution would be an electronic crossover, and two separate amps for sub and satellite. The active crossover allows a easily variable frequency and relative level adjustment.
As alternative a passive crossover shall be deigned and built. The Kef Cantata has a 250Hz cut between B139 and B110, and it's possible to replicate this section of the crossover.
Other examples are avalable. Unfortunately, no flexibility to choose different schematics unless spending a lot of money in experimentation.
In both cases, active and passive designs, the advantage compared with sub modules or commercial subwoofers is the high pass filtering of satellites, giving higher power capability than full range use of them.
Thanks for the attention, and for the opinion somebody may add.
Regards
Roberto
Last edited: