Hello audio community;
I have a pair of old (1989) Infinity kappa 8. The midranges and enclosures need major fixing/replacing. I was able to get my hand on 4 (four) BG Neo 8 drivers.
I'm trying to keep the replacement as simple as possible. I only have basic welding/soldering skills.
Here are the questions:
1. Can I use them with the existing crossovers ?
2. Should I use just one or can I use two BG's ?
3. If I can use a pair/cabinet, how do I wire them ?
4. What modifications will I need ?
This should render a final product quite similar to the Infinity Interludes a very good quality speaker in its own right !!
Opinions, recommendations are welcome.
I have a pair of old (1989) Infinity kappa 8. The midranges and enclosures need major fixing/replacing. I was able to get my hand on 4 (four) BG Neo 8 drivers.
I'm trying to keep the replacement as simple as possible. I only have basic welding/soldering skills.
Here are the questions:
1. Can I use them with the existing crossovers ?
2. Should I use just one or can I use two BG's ?
3. If I can use a pair/cabinet, how do I wire them ?
4. What modifications will I need ?
This should render a final product quite similar to the Infinity Interludes a very good quality speaker in its own right !!
Opinions, recommendations are welcome.
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Nearly 100 views and not a single comment...
I will make specific questions regarding my doubts. The questions may sound stupid, please bear with me, I'm a newcomer into planar speakers...
I realize in phase vs out of phase is significant in planars. If I want them in-phase, do I wire them: in parallel or in series? The impedance and resistance part I can deal with.
If I'm going to add resistances and inductors, Do I place them on a general planar circuit or do I use individual elements on each of the speakers?
I will make specific questions regarding my doubts. The questions may sound stupid, please bear with me, I'm a newcomer into planar speakers...
I realize in phase vs out of phase is significant in planars. If I want them in-phase, do I wire them: in parallel or in series? The impedance and resistance part I can deal with.
If I'm going to add resistances and inductors, Do I place them on a general planar circuit or do I use individual elements on each of the speakers?
1. Probably not and they'd probably sound really bad unless you were really, really lucky. Are you able to read the PCB/wiring and create a wiring diagram of what is there?
2-4 depend on answer 1.
Trying to mate the Neo 8 into an existing loudspeaker certainly isn't a drop-in replacement. And the Infinity Kappa 8 is far from a conventional loudspeaker. It is a 4-way design with crossover points at 90Hz, 700Hz, and 5000Hz, as well as a supplementary rear firing tweeter. Julian Hirsch, in Stereo Review, noted that it had a very low impedance, typically 3 ohms and lower. Often a low impedance means greater sensitivity (volume) for a given voltage, but the Kappa 8 seems to be rather insensitive. To match the Neo 8s you will probably have to L-pad their sensitivity down to match the other drivers, and match the resulting load impedance to the driver you are replacing so that it will give the correct crossover frequencies with the existing network. And, assuming you are replacing the midbass driver, asking the Neo 8 to operate down to 90 Hz might be more than even a pair of them could handle.
Aside from that, the crossover is complex and featured many large nonpolarized electrolytic capacitors that have probably dried up over the years. It is very likely that the crossover points have drifted and the speaker doesn't sound anything like it did when new.
If it were my choice I'd rather use the Neo 8s to build a new system.
Aside from that, the crossover is complex and featured many large nonpolarized electrolytic capacitors that have probably dried up over the years. It is very likely that the crossover points have drifted and the speaker doesn't sound anything like it did when new.
If it were my choice I'd rather use the Neo 8s to build a new system.
Hi,
Nothing simple about what you are trying to do,
and any simple approach will be very wrong.
Its the sort of thing if you have to ask, you
really shouldn't be doing it, as its complicated,
and you wont get any good simple answers.
The resonant LC tuning of the bass unit turns
it into a vicious load in the bass, very unusual.
http://www.infinity-classics.de/technik/manuals/Kappa_8_technical_sheet.pdf
rgds, sreten.
The 5" dome is really very pointless, a solution looking
for a problem that doesn't exist over its working range.
Nothing simple about what you are trying to do,
and any simple approach will be very wrong.
Its the sort of thing if you have to ask, you
really shouldn't be doing it, as its complicated,
and you wont get any good simple answers.
The resonant LC tuning of the bass unit turns
it into a vicious load in the bass, very unusual.
http://www.infinity-classics.de/technik/manuals/Kappa_8_technical_sheet.pdf
rgds, sreten.
The 5" dome is really very pointless, a solution looking
for a problem that doesn't exist over its working range.
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Before you give up on the 8 Kappas, here is what I did to a pair I found in a local consignment shop:
1. Refoamed the woofers.
2. Bypassed the LC arrangement on the woofer circuit.very simple.
3. Replaced the polydomes with 3" Tang Band bamboo full range drivers. Had to make a faceplate adapter to fit the baffle.
That's it. No other crossover changes. Stunning sound for little money.
Since then I have repaired the polydomes but prefer the TB sound by a small margin.
Peter
1. Refoamed the woofers.
2. Bypassed the LC arrangement on the woofer circuit.very simple.
3. Replaced the polydomes with 3" Tang Band bamboo full range drivers. Had to make a faceplate adapter to fit the baffle.
That's it. No other crossover changes. Stunning sound for little money.
Since then I have repaired the polydomes but prefer the TB sound by a small margin.
Peter
Something similar, to what you're proposing, has been done before:
A new Kappa emerges. - AudioKarma.org Home Audio Stereo Discussion Forums
So, don't give up, if you really would like to try this mod. Just define the speaker, with a mock-up, before making any permanent changes to your Kappa 8 cabinets. Maybe study the Kappa 8 crossover schematic, and compare it to a DIY build, using Neo 8's. You should get a pretty good idea, that way, on what components would need to be changed, in order to support the Neo's:
http://infinity-classics.de/technik/manuals/Kappa_8_technical_sheet.pdf
Good luck!
A new Kappa emerges. - AudioKarma.org Home Audio Stereo Discussion Forums
So, don't give up, if you really would like to try this mod. Just define the speaker, with a mock-up, before making any permanent changes to your Kappa 8 cabinets. Maybe study the Kappa 8 crossover schematic, and compare it to a DIY build, using Neo 8's. You should get a pretty good idea, that way, on what components would need to be changed, in order to support the Neo's:
http://infinity-classics.de/technik/manuals/Kappa_8_technical_sheet.pdf
Good luck!
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