Infinity Kappa 8

[smpl]

Hey all. This is my first post and I'm sorry if this has been discussed before.

I own a pair of Infinity Kappa 8's probably bought in the early 90's. Recently I blew the sub of a speaker. Ouch.

I need help deciding where to go from here ie where to buy a new sub, how to install it and costs. I would also appreciate some advice on my audio system (I'm not that knowledgable and it would be useful to know if i have the right equipment). alternatively if i find replacement is not feasible, help on how to sell them and what price to expect.

Any help would be appreciated...

Regards

Brian

System Specs:
Power amp:
NAD 216THX
Preamp
NAD 106

[SicMan]

Welcome smpl: :music:

Sorry to here about the woofer, if it's truely blown or unfixable, some show up on Epray or you can check around to see if a repair shop can help you out. Not sure if they still sell new ones. Maybe some else will chime in here with more info for ya.

John

[yamahammer]

nice speakers well worth refoaming or repairing www.wooferrepair.com comes to mind as a place to start.plus look down at the bottom of the page don't know where your at so local help could be available

[macaltec]

nice speakers well worth refoaming or repairing www.wooferrepair.com comes to mind as a place to start.plus look down at the bottom of the page don't know where your at so local help could be available

Welcome. I'll second the need for location information. If we knew where you were we might be able to direct you to a fellow member than can help you out.

[Negotiableterms]

Welcome aboard! Good first post. Definitely need your general locale, which you can add in the User Control Panel. City, or even just state will work.

Kappa 8s are great speakers. It would cost you thousands to equal their sound with current products.

Before we go any further, please describe what you mean by "I blew the sub of a speaker"? At 15 years old, those subs (called woofers) are likely in need of new surrounds. The voice coils can rub, and short out. Depending on what happened, the woofer may be repairable, or may truly be blown.

In addition, these woofers appear all the time on eBay. They're the same as the woofers in the Kappa 9, and I think, some other models.

NAD makes nice gear. Not what I'd have chosen to match with K8s, but it should still sound better than 90% of what's in stores today.

Again, welcome aboard!

[smpl]

Hi all

I have posted my problem on two other forums and you guys have been by far the most useful...

To SicMan, yamahammer, macaltec and Negotiableterms: thanks for your replies.

I've updated my profile. I am from Dunedin, New Zealand. For those who don't know it's South East for Australia, ie very far way and one of the reasons why this is a bit complicated...

My knowledge is very limited, so I am going to need your help of coming to a solution. It sounds like the first answer has been found:

Step 1: Keep the speakers and repairing them.
Reason: Replacement speakers will cost too much.
Question: Can this be justified. How much could i get for them? Where could I sell them? ( i understand these speakers are highly sought after). How much am i looking at for replacement speakers.

Anyway. If it still turns out that replacement is the next best option, we need to establish the problem.

Negotiableterms wrote:
Before we go any further, please describe what you mean by "I blew the sub of a speaker"? At 15 years old, those subs (called woofers) are likely in need of new surrounds. The voice coils can rub, and short out. Depending on what happened, the woofer may be repairable, or may truly be blown.

I fully understand. I think this is the next important step. Is there any chance someone could give me a step by step guide to figuring out whether the woofer's gone, or whether the surrounds are damaged.

The way i see it is this is what will follow.

Step 2: Deciding what need's replacing.

Step 3: Deciding whether there are any other 'upgrades' i should investigate ie should the other speakers subwoofer get refoamed?

Step 4: Purchasing and installing whatever is needed....

Step 5: Checking that replacement is still the best option as opposed to selling.

Sorry for the essay, but due to my lack of knowledge and limited funds (poor student), being thorough is important. Any help will be much appreciated. Regardless this should be a good project with a learnign curve.

Regards

Brian

[smpl]

to speed things up a bit, here is some recent events. please still respond to my previous post.

Ok Brian, here's an easy way to determine what is wrong.

To check the surrounds, simply take the grilles off of the speakers and look closely at the foam surrounding the speaker, inspecting for cracks/breaks, etc. Also run your finger around the foam, as sometimes the cracks are hard to see until the foam is moved.

If you find the foam(s) to be cracked and/or broken, you have probably found your problem. This will typically cause a "buzzing" sound during bass notes, making the speaker sound blown.

If the foams seem to be intact, the next step is to give a closer inspection to the woofer. Place your fingers around the cone of the speaker (roughly spread around the center in an even dispersion), and gently push the cone inward with your hand. Take care to push it straight in. If there is a scraping noise or if the speaker doesn't want to move, it probably is blown.

So, if you find the speaker to be blown the next step is replacement. Because of your location/budget constraints I believe this is the best remedy possible. The best course of action here is to find a direct replacement (i.e., the same speaker) to replace it with. Once you have gotten the replacement woofer, it is as easy as unscrewing the broken one, unattaching the wires, attaching them to the new speaker, and screwing it in. Infinity doesn't use solder, so you should be able to simply pull the connections from the speaker and directly attach them to the new one. Then screw the new speaker in, and you're done!

I think the best action for you to take if the speaker is blown is to e-mail Infinity's (Harman actually, their parent company) parts administrator at parts@harman.com. They should be able to help you find a replacement woofer.


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thanks ****. that was very useful... I've done as you said. The foam seems to be fine. When i push the broken woofer in an out i hear a sraping noise. When I so the same for the other speaker it sounds fine. When i tap the working speaker it gives a nice bass sound, but for the broken one a thuddign sound (this sound is hard to describe. thudding is the best description i can think of - clearly not good)....

I will email around and check out prices.

[Negotiableterms]

Well, Brian, it sounds like you're most of the way there. My only advice at this point would be to be patient and look on eBay. I see these woofers often, and while it's possible, but unlikely, that Harmon has replacements, they'll charge highly for them.

Other than that, you're on your way!

Take a look around this forum and the rest of the site, and hang out a while!

[smpl]

1. there are many matches for "infinity subwoofers" search on ebay. what am i looking for?
2. regarding my system: my poweramp sometimes cuts out when i play the speakers very loud for a long time. how do i check that it is the right amp for the job? do i need another one?
3. why did i blow my speaker in the first place?

[Charivari]

1. there are many matches for "infinity subwoofers" search on ebay. what am i looking for?
You're looking for a woofer, not a subwoofer. This might seem like a nit-picking thing, but it makes quite a difference as it's a woofer you need for your speaker whereas Infinity subwoofers are made for separate bass units and automobile installations. Now, as to what driver (woofer) you need, you can locate that information on the technical sheet PDF found here (http://www.infinity-classics.de/infinity/manuals/Kappa_8_technical_sheet.pdf). The specific driver you're looking for has a parts number of 902-3054. If you keep doing an eBay search for Kappa drivers, look into the woofer listings when they show (none right now) and check the pictures or ask the seller to make sure this number is printed on the back of the magnet. That way, you can be sure you're getting the right part.

2. regarding my system: my poweramp sometimes cuts out when i play the speakers very loud for a long time. how do i check that it is the right amp for the job? do i need another one?
When your power amp cuts out, it's most likely kicking into protection. This means that unless it's in need of a technician to look at it, you're driving it and the speakers too hard causing the protection relay to kick in to keep from burning up expensive parts in the amp. Seeing how the woofer was blown, it's likely not the amp that's the problem but the levels you're trying to play your system at. (There could also be a problem with the impedance load the speakers present to the amplifier. Infinities are notorious for dipping a bit low and so lesser amplifiers that cannot handle the loads tend to heat up very fast and trigger the protection circuitry as well. The rest of this answer still applies in this situation as the issues are related.)

The only practical solution here is to either back off the volume/boost a bit (if you have the bass turned up on your preamp, it requires much more power than a flat setting -- ie 3dB of bass boost calls for twice as much power from the amp at the bass frequencies, 10dB calls for 10x as much) or purchase a bigger amp. The latter option is the best as you'll still be able to enjoy music at the volumes you like (outside of the exceptions listed in the answer to question 3) and you won't be clipping the amp and thus risking further damage to your speakers. What I mean by this is that your amp was driven hard enough to trip the protection circuitry. By this point, the amp was likely clipping -- where the outputted waveform peaks at a higher power than the amp can provide and so the top of the waveform is clipped flat into a plateau and thus the amplifier puts out straight DC voltage. You can't hear the DC, but you will hear a strong distortion that can easily be mistaken for the "loud" you hear in lesser systems. This clipping will kill drivers in a hurry, especially the fragile tweeters that will burn up in a hurry and thus cost you even more money in repairs beyond your blown woofer.

So, your amp isn't the right one for the levels you enjoy, though with a subwoofer as mentioned in answer 3, you might be able to get away with it for a while longer.

3. why did i blow my speaker in the first place?
You answered this question in part with your question 2. Your speakers were simply overdriven. Whether you played your system too loudly or you had the bass boosted forcing more power to the woofer than it was designed for thermally or it was moved too far (over-excursion), too much was asked of the woofer. In the first instance, too much power overheats the voice coil causing the glue binding it to the former (the paper, metal, or ceramic tube around which the magnet wires of the VC are wrapped) to simply melt or burn up loosing the wires. They then fall out of place and bind up in the gap causing the rubbing sound you hear. The second possibility is when the woofer moves too far causing the VC former to slam into the back of its gap, deforming the VC causing it to bind. For either of these cases, the solution is to back off on the volume and the bass boost. If you can't resist the temptation to crank it (something I wholly understand), then you'll want to pick up a good (not car) subwoofer. You can use it to produce the bass you want while the crossover inside will cut off the lower frequencies going to your Kappas making them more capable of higher volumes without blowing another woofer (provided you have sufficient amp power, which is not the case right now, and that the other drivers can handle the power).

- JP