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Kappa 9 Woolly/Thin Bass

737plaidfan

737plaidfan

New Member
Hello fellow Infinity enthusiasts! I've been a fan of Infinity speakers of the Kappa flavor for years. I really think that if properly amped they deliver some incredibly pleasing sound at a (relatively) wallet-friendly cost. I've owned the Kappa 8.1s, which I adored, and then the Kappa 9s, which are out of this world.

I am writing about my Kappa 9s, which for various reasons have gone unused for a couple of years.

The speakers are being run from a Brooklyn Bridge DAC, through a balanced out to a Sunfire tube preamp, and then to a Sunfire Signature load invariant power amp (the 300 watt version). While I didn't really notice this before, after listening to some high end headphones (Meze Empyrean, Hifiman HE1000se), I have noticed that my Kappas are lacking bass and definition below 60 hz or so. Based on what I've read about these speakers, the bass should be robust and rich, almost to the point of being a little too much for a small room, and obviating the need for a separate subwoofer.

My questions are as follows:
1. Do I need more amp? The Sunfire that I have is good down to and a bit below 1 ohm, but might not deliver sufficient current.
2. Do I need a new preamp? Are tubes a bad choice for the Kappas? My Sunfire uses a matched triplet of Amperex Holland ECC88 / 6DJ8 that were recently acquired.
3. Could the issue be cables? I'm using good quality, but not expensive/audiophile grade XLR cables. My speaker cables are banana plug terminated 12AWG ones, again good quality but not expensive.
4. Could I benefit from using a power conditioner of some sort?
5. Could the woofers benefit from a refoam?
6. Could the crossovers be going bad? Due to a move the speakers had to be stored in a non climate controlled facility for nine months.

I realize this is a big wall-o-text, and I greatly appreciate those who have read this far.

Thanks much! I look forward to chatting with you all.
 
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From my personal experience with Kappa 9s

1) I drove mine with a Sunfire S300 and never had a issue with lack.of bass.
2) I don't have experience with running a tube preamp but I don't see how it would contribute to lack.of bass unless something is amiss in the tone control circuitry.
3) I've tried a few different speaker cables and never really noticed any lack of bass.
4) if anything, a power condition could make things worse if not of very high quality and able to allow uninterrupted current flow required by high power amps.
5) Worn surrounds could be a possibility but usually contributes more to "mushy" bass. I had this issue with Kappa 8.1s.
6) Bad/out of spec caps could cause an apparent lack of bass. I did notice this phenomenon with my Kappa 9 before a recap of all the NPE caps. Prior to the recap I had to turn the EMITs and polydomes down to get the balance close. After the recap which replaced all the woofer caps I had to turn the EMITs and polydomes back.up to the nominal settings to get the balance back.

Room placement is also critical. I could literally move 2-3 feet in any direction and the apparent low bass would change quite noticeably. Before committing to refoams or recaps try moving them around the room a bit.
 
Was any work done on the speakers before you put them in storage? One possible explanation is that the woofers are wired out of phase. Or the woofers in one speaker are out of phase relative to the other speaker. Or even that the speakers are connected out of phase (e.g. the left channel has the amp + connected to the speaker +, and the right channel has the amp + connected to the speaker -).

Regarding the woofer foam, has it ever been redone? I've owned a few pairs of the original Kappas, and all of them had foam that expired at least 5 years ago, or longer. Give it a gentle poke; if it tears then it needed replacing anyway.
 
Thank you both for your replies!

I am glad to say that the speakers weren't hooked up to my amp out of phase. I was awake and fully caffeinated when I hooked them up to the amp. I double checked to make sure, and all was good.

I had a feeling it wasn't the amp. These Sunfire Signatures are basically arc welders. I will try and move them around my listening room to see if that makes a difference. I also have a sinking feeling that it very well might be the caps. I purchased these used in 2015, and was told by their original, previous owner that nothing had ever been done to them. It might be prudent, if the repositioning fails, to find a good speaker doctor who can operate on vintage Infinities. Fortunately, I live near a big city, so that hopefully won't be an issue.

I will avoid power conditioners, then. I had not considered that they might not perform well when paired with a high current amplifier.

I don't think the foam has ever been redone. I poked the foam surrounds, and while they didn't tear, my finger imprint lingered for a while before it bounced back. That can't be good.
 
swechsler said:
Was any work done on the speakers before you put them in storage? One possible explanation is that the woofers are wired out of phase. Or the woofers in one speaker are out of phase relative to the other speaker. Or even that the speakers are connected out of phase (e.g. the left channel has the amp + connected to the speaker +, and the right channel has the amp + connected to the speaker -).

Regarding the woofer foam, has it ever been redone? I've owned a few pairs of the original Kappas, and all of them had foam that expired at least 5 years ago, or longer. Give it a gentle poke; if it tears then it needed replacing anyway.
Click to expand...
That's what I was thinking. Phase issues as a possibility.
Those are old enough it would seem the foam would have been replaced by now, or be needing replacing now.
Did you use them right after you got them for a period of time long enough to hear the bass was ok after purchase? Or did you give them a short listen then put them away until recently hooking them up again?
If the seller was indeed the original owner it's possible the foams went bad and were replaced decades ago and he forgot.
While you state you know the wiring at the amp was correct, what about the wiring of each speaker?, As mentioned out of phase and lacking in bass or muddy not focused bass is not all that uncommon especially with Infinitys with dual woofers.
 
I bought them quite a while ago (2015 I think?), and while I gave them a quick audition (Eric Clapton and BB King's Riding With The King) I mainly used them in a casual setting (e.g. Frank Sinatra or similar during dinner or other material with limited bass) and only engaged them in critical listening sessions until just before they were put into storage. I was so addlepated at the time during my move that I couldn't tell you if they sounded out of phase. It certainly sounds like it could be an issue. Since my training is in economics, not electrical engineering, I should probably take these in for service to have them evaluated. I do not want to make a mistake and break something that's 35+ years old.
 
737plaidfan said:
I don't think the foam has ever been redone. I poked the foam surrounds, and while they didn't tear, my finger imprint lingered for a while before it bounced back. That can't be good.
Click to expand...
No, that foam has expired. Refoaming these is doable for the amateur; although I'm not going to say that they're the easiest to do, we have plenty of members who've done it. Getting the woofers connected correctly internally is not a big deal.

737plaidfan said:
Since my training is in economics, not electrical engineering, I should probably take these in for service to have them evaluated. I do not want to make a mistake and break something that's 35+ years old.
Click to expand...
That might not be a bad idea, particularly if you've never done any crossover work before*. However, I'd only bring them to someone who has experience with high end speakers, or at least with quality speakers in general. If you can't find anyone local, you could refoam the woofers yourself (assuming you feel comfortable with it), and remove and ship the crossovers out to an expert. If you decide to do that, ask us here for the best way to do it. Obviously shipping these cabinets will be next to impossible.

* I had originally written that the K9 crossovers are complex, but just having had another look (below) at them, they don't seem that bad. If you're technical, and willing to learn how to solder and test components, you could probably do it yourself.

iu
 
It appears the Kappa 9 schematic, if correct, shows colors of the wires to each driver. That should make checking for proper connections easy. Remove the screws holding the woofers to the cabinet and pull the woofer out far enough to see if the color code wires are connected to the proper terminals for each woofer.
No idea how much each woofer weighs but gravity will probably be in place so don't let them fall or hang by the wires when removing or inspecting.
I can't get the schematic on Klaus's site to open right now, but here's a schematic I found online, I wish it was larger. Hopefully you can read the color codes for the wires.
OK, just paused my vpn and Klaus's site is working for me.
Kappa 9 info and link to schematic here http://www.infinity-classics.de/models/Kappa-series-1987/index-Kappa.htm
Schematic here http://www.infinity-classics.de/technik/manuals/Kappa_9_technical_sheet.pdf
infinity-rs9-kappa-crossover-jpg.518591
 
If that is indeed the schematic, check the position of SW 1.

If the foam isn't firm and springy, it's dead and leaking air, which is why you have poor bass. Refoam definitely in order.

And, depending on age and use, the caps may well be going bad, but that won't affect the woofer any, only the others.

Low frequency bass is a huge issue in homes, the actual waveforms for anything under 50Hz is the size of the room or larger, so you get all kinds of interference problems, and you may be sitting in a null zone where it actually cancels out.
 
Very much so, high ESR is just the same as a resistor when it comes to current transfer. I missed that, all the stuff I have has the woofer directly connected.

Cap coupled inside a speaker box, hmmm.
 
goodolpg said:
It appears the Kappa 9 schematic, if correct, shows colors of the wires to each driver. That should make checking for proper connections easy. Remove the screws holding the woofers to the cabinet and pull the woofer out far enough to see if the color code wires are connected to the proper terminals for each woofer.
No idea how much each woofer weighs but gravity will probably be in place so don't let them fall or hang by the wires when removing or inspecting.
I can't get the schematic on Klaus's site to open right now, but here's a schematic I found online, I wish it was larger. Hopefully you can read the color codes for the wires.
OK, just paused my vpn and Klaus's site is working for me.
Kappa 9 info and link to schematic here http://www.infinity-classics.de/models/Kappa-series-1987/index-Kappa.htm
Schematic here http://www.infinity-classics.de/technik/manuals/Kappa_9_technical_sheet.pdf
infinity-rs9-kappa-crossover-jpg.518591
Click to expand...
This is very helpful. I will take a look when I get home from work. Thanks very much!
 
swechsler said:
No, that foam has expired. Refoaming these is doable for the amateur; although I'm not going to say that they're the easiest to do, we have plenty of members who've done it. Getting the woofers connected correctly internally is not a big deal.


That might not be a bad idea, particularly if you've never done any crossover work before*. However, I'd only bring them to someone who has experience with high end speakers, or at least with quality speakers in general. If you can't find anyone local, you could refoam the woofers yourself (assuming you feel comfortable with it), and remove and ship the crossovers out to an expert. If you decide to do that, ask us here for the best way to do it. Obviously shipping these cabinets will be next to impossible.

* I had originally written that the K9 crossovers are complex, but just having had another look (below) at them, they don't seem that bad. If you're technical, and willing to learn how to solder and test components, you could probably do it yourself.

iu
Click to expand...
I am *somewhat* technically minded. I have built computers and custom water cooling loops, and can install a garbage disposal without shorting out my entire neighborhood lol. But I've never done any kind of electrical work. I don't even know how a capacitor works. I look at that circuit board and while I'm sure I could learn to solder without too much trouble, I wouldn't want my first project to be the heart of my beloved speakers. Here's one of the speaker hospitals I've found that's close to me: https://bammeltv.com/stereo-repair-service-electronics-repair-service-in-houston-tx/ Could this be a good choice? I do intend to call them and ask if they have any experience with the Arnie Nudell designed Infinity speakers.
 
737plaidfan said:
Could this be a good choice?
Click to expand...
From the website, it sure looks like it, but anyone can put anything they want on a website. I would call them and discuss the issues, mention the refoaming, and see what they say. I doubt they'll give you an estimate over the phone, unless you give them a specific request like "refoam all four woofers and replace all capacitors". Even then they'll probably say they need to see them to ensure there's nothing else wrong (and there may be a diagnosis fee).
 
swechsler said:
* I had originally written that the K9 crossovers are complex, but just having had another look (below) at them, they don't seem that bad. If you're technical, and willing to learn how to solder and test components, you could probably do it yourself.
Click to expand...

You are only seeing the top side of the board. The underside is where most of the NPE caps are located and they are the ones that would be most in need of replacing. Trust me, its not as easy as it looks especially when the board still has all the wires attached to the drivers.
 
737plaidfan said:
I am *somewhat* technically minded. I have built computers and custom water cooling loops, and can install a garbage disposal without shorting out my entire neighborhood lol. But I've never done any kind of electrical work. I don't even know how a capacitor works. I look at that circuit board and while I'm sure I could learn to solder without too much trouble, I wouldn't want my first project to be the heart of my beloved speakers. Here's one of the speaker hospitals I've found that's close to me: https://bammeltv.com/stereo-repair-service-electronics-repair-service-in-houston-tx/ Could this be a good choice? I do intend to call them and ask if they have any experience with the Arnie Nudell designed Infinity speakers.
Click to expand...
IMO there is no shame if you feel a procedure is beyond your capabilities or confidence level. Better to let a "pro" do it than DIY and then make things worse or create an issue that didn't exist before the DIY attempt.
AK'ers have talked me through some procedures and others I have left to the people that do it for a living.

I don't have any knowledge about the service place you asked about, hopefully others will, or can suggest a suitable shop that you might consider.
 
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