Should I Just Give Up on These Speakers?

[tmtomh]

Hello all,

As noted in another thread, I recently inherited a pair of Infinity Kappa 9 speakers, in excellent shape with replaced woofer surrounds and a drop-in replacement for the original polydome midrange. They are excellent speakers in some respects, but I am having a very difficult time trying to dial in their in-room frequency response - and I am getting extremely frustrated trying to use Dirac with a MiniDSP SHD to achieve proper response.

I've taken several sets of measurements, using 9 or 13 measurements as Dirac recommends, and also using fewer measurements as some folks here recommend. I've tried using Dirac correction only from 300Hz down, as some advise, and also using it full-range, as others here say they've done successfully. I've also tried in-between corrections, up to 700Hz and up to 4kHz.

Finally, I've tried using several different target curves: Dirac's new default, which appears to be a Harmen/Toole-esque curve with about 8dB bass boost at 20Hz and sloping to about -0.5dB at 20khz. I've also tried the so-called "Harman curves" that are floating around online (I know there's not really a Harman curve), with 6dB and 10dB boost at 20Hz, and I've tried tapering to -1.5dB, -3dB, and -6dB at 20kHz (while keeping the curve linear until about 2.5kHz).

With that said, here is what Dirac shows as the response from 13 measurements (top image) and from another, separate round of 7 measurements (bottom image). To be clear, these are the pre-correction responses.

Note not only the nonlinear response, but also that the scale is 10dB per vertical unit. According to Dirac, there's an 8dB dip at 5kHz compared to about 2.5Khz and about 7kHz. There's also about 4-5dB of nonlinearity at various points from the Schroeder frequency up to 1kHz.

This just seems awful - or am I expecting too much from a non-smoothed response graph of passive speakers with no built-in DSP?

Now, the speakers don't actually sound to me the way this curve suggests. But they don't necessarily sound quite right either. I don't even know exactly what Dirac is showing me here - is this an average of in-room response from all the measurements? Or has Dirac used those multiple measurements to calculate a quasi-gated or quasi-anechoic response curve for the speakers here? If I'm not supposed to use Dirac to flatten the response above about 300Hz, and I can't use these Dirac measurements as indicators of what my ears are actually hearing in-room, then how am I supposed to use PEQ to try to flatten the response?

Should I just give up and sell these speakers and get an active speaker with built-in DSP instead? I feel like I'm caught in a classic circle of confusion, no longer being able to tell with confidence if the tonality of my music is right or not, and seemingly having no dependable way to know how I should actually be EQ'ing these speakers above 300Hz for decently accurate response. I mean, can we simply not own speakers if they are too old to have spinorama data available?

As might be obvious from this post, I'm kind of at the end of my rope at this point. I feel I've tried my best here and I'm most definitely not having fun anymore at this point. I would be grateful for any perspective, guidance, advice, or helpful thoughts anyone can provide, to help me better understand what I'm looking at here and perhaps how I might come to an informed decision about continuing to work with these speakers versus giving up.

Thanks!

 

[Galliardist]

What is the rest of the system? The Kappa 9 is supposed to have very low impedance in the bass, and your EQ issues may be being caused by your amplification running out of steam. In subjectivistland these are "amp killers" by reputation.

I'm also quite uncertain of that dip at 5 kHz. Without measurements of an original, I'm wondering there are other replacement drivers in there apart from the drop-in midranges, and that something is wrong there.

 

[MarkS]

The 5kHz dip might be a crossover issue, either a cap gone bad, or possibly the replacement driver not having the same impedance (but it should if it's intended specifically as a replacement).

 

[DavidMcRoy]

The 5kHz dip might be a crossover issue, either a cap gone bad, or possibly the replacement driver not having the same impedance (but it should if it's intended specifically as a replacement).

Or maybe the tweeter is wired out of phase? (That ill-advised arrangement can create a false sense of deeper imaging, but I'm not a fan, obviously.)

 

[restorer-john]

I get the circle of confusion thing. After all, you don't know what the repsonse of the speakers in your room with original midranges would have been like. Is it by design, are the new mids causing this or is there another issue?

Are you using the rear controls in an attempt to flatten the response and if not, are they backed off or all set at default?

 

[sam_adams]

The crossover those speakers is very complex and has some quirky polyswitches that can go bad which will effect the output. Take a look at the two discussions below to get an idea of what's going on there.

New Kappa 9 speakers how to disassemble the crossover?

Kappa 9 poly switch/Crossover

 

[restorer-john]

The crossover those speakers is very complex and has some quirky polyswitches that can go bad which will effect the output. Take a look at the two discussions below to get an idea of what's going on there.

New Kappa 9 speakers how to disassemble the crossover?

Kappa 9 poly switch/Crossover

Good point. Old polyswitches made in the early days of the devices can go bad.

 

[tmtomh]

Really appreciate these responses - thanks!

@Galliardist - very good question about the rest of the system. I'm driving the Kappas with an Audiophonics Purifi-based amp. I'm also using the speakers with their bass switch set to "Normal" mode and not "Extended" mode. "Extended" mode is what gives these speakers that notorious 0.8 ohm impedance around 30Hz. In "Normal" mode, extra resistance is added to the bass circuit, somewhat reducing bass output in the lowest octave but changing the load to approximately 4 ohms. For my taste, they still have plenty of bass in Normal mode.

My understanding is that the only remaining low-impedance area with the speakers in Normal mode is a dip to 1 ohm around 10kHz. Given that, and the Purifi amp's current capacity, power, and load invariance, plus the fact that these measurement test sweeps are being run at modest volume (like 70dB or so), I don't think the amp is a problem here.

@MarkS - I think you are probably right that the 5kHz dip is a crossover issue. The crossover from the midrange to the tweeter is at 4.5kHz (and at least one online source says it's at 5lHz). The replacement midrange has the same nominal impedance as the original (some replacements don't) - but it is still known to be a little more sensitive in practice than the original. So it stands to reason that it's probably an interaction between the crossover and that midrange driver.

@restorer-john - I have adjusted the rear L-pads multiple times and ways to try to flatten the response. The graphs I shared above are with the midrange pot set to minimum: the increased sensitivity of the replacement midrange means that the pot cannot attenuate it quite enough, so while its response is fairly linear (its crossover points are 800Hz and 4500Hz), it runs a couple dB hot, as evidenced in it being over the 0dB mark in the graphs. As for the tweeter and super tweeter, the top graph is with both their pots around 11 o'clock, and the bottom graph is with the tweeter backed off a bit more to 10 o'clock and the super tweeter turned to 7 o'clock, its minimum setting. (Infinity has 2 o'clock marked as "nominal," but I've read online that for a typically reflective room those nominal levels are generally considered too bright/hot). I also don't know how exactly the L-pads work: one would assume they simply lower the output of the given driver across its entire range. However, if they are adding resistance in the crossover network, I assume it's possible that they could affect the output of each driver in a nonlinear fashion, and with the drivers' outputs overlapping near the crossover frequencies, I suppose it's possible that turning the L-pads up or down could potentially increase crossover-area nonlinearities. I don't know.

@DavidMcRoy - interesting point about the tweeter being out of phase. I'm pretty sure it is not. However - there is a 2nd, rear-facing tweeter on these speakers (a goofy design choice IMHO), and I wonder if that is intentionally wired out of phase, or if perhaps front-wall reflections from that rear-firing tweeter could be creating a null by partially canceling the output of the front-facing tweeter. Does that sound plausible?

@sam_adams - I am far from an expert in this area, but based on the two threads you linked to (thanks!), it doesn't seem like the problem here is broken/open switches. All the drivers are working, and the speakers don't sound "broken" to me. In fact, with some of the measurements, target curves, and settings I've tried, they sound fantastic.

My problem is a perceived lack of consistency. With some music they sound "right" - even if the recording isn't great, it sounds tonally correct for what it is. But then with some other music something sounds slightly, naggingly "off," usually somewhere in the 2-7kHz range depending on the material. The various sets of measurements I've taken seem to produce similar results (as per those two graphs), but not identical results. So depending on which sets of measurements I use, which corresponding L-pad settings I use on the back of the speakers, which target curve I use, and whether I have Dirac correct to 300Hz or all the way up to 20kHz, I find that it changes which music sounds "right" and which music sounds "not quite right." And that's where I feel like I'm chasing my tail.

My previous speakers - B&W 705s - were in a whole other class, with less bass extension (and I'm sure less clean bass) and a smaller soundstage. And their un-EQ'd treble linearity sucked because of the B&W "showroom sound" boost around 4-5kHz. But with some simple EQ, I was able to get them to sound consistently "right" in a basic way with all of my music. In other words, I was aware of their limitations, but those limitations did not get in the way of relaxing, enjoyable listening, and those limitations did not seem to surface only with certain types of music. The consistency of sound was there, and I was able to get to a "set it and forget it" place with them. That's the place I'm really struggling to get to with these Kappas - and I'm not someone who enjoys constant tinkering.

 

[Deleted member 48726]

The crossover those speakers is very complex and has some quirky polyswitches that can go bad which will effect the output. Take a look at the two discussions below to get an idea of what's going on there.

New Kappa 9 speakers how to disassemble the crossover?

Kappa 9 poly switch/Crossover

Polyswitches usually gets stuck in the NC position e.g. that they don't lead anything to the negative but acts as a wire instead.

 

[Deleted member 48726]

Try to just do the Dirac Correction across the dip area 5k Hz. All other Dirac points you should try to hug the original response. You can do what you know works or like in the bass/mid bass though.

 

[sam_adams]

@sam_adams - I am far from an expert in this area, but based on the two threads you linked to (thanks!), it doesn't seem like the problem here is broken/open switches. All the drivers are working, and the speakers don't sound "broken" to me. In fact, with some of the measurements, target curves, and settings I've tried, they sound fantastic.

I should have pointed out the link to the manual with the schematic for the crossover in the discussion:

Infinity Kappa 9 technical Sheet.

This guy restored his Kappa 9s. Subjective evaluation is provided in the discussion.

 

[Deleted member 48726]

Another experiment you could do with Dirac is force cutting.. Like this

 

[Tangband]

Hello all,

As noted in another thread, I recently inherited a pair of Infinity Kappa 9 speakers, in excellent shape with replaced woofer surrounds and a drop-in replacement for the original polydome midrange. They are excellent speakers in some respects, but I am having a very difficult time trying to dial in their in-room frequency response - and I am getting extremely frustrated trying to use Dirac with a MiniDSP SHD to achieve proper response.

I've taken several sets of measurements, using 9 or 13 measurements as Dirac recommends, and also using fewer measurements as some folks here recommend. I've tried using Dirac correction only from 300Hz down, as some advise, and also using it full-range, as others here say they've done successfully. I've also tried in-between corrections, up to 700Hz and up to 4kHz.

Finally, I've tried using several different target curves: Dirac's new default, which appears to be a Harmen/Toole-esque curve with about 8dB bass boost at 20Hz and sloping to about -0.5dB at 20khz. I've also tried the so-called "Harman curves" that are floating around online (I know there's not really a Harman curve), with 6dB and 10dB boost at 20Hz, and I've tried tapering to -1.5dB, -3dB, and -6dB at 20kHz (while keeping the curve linear until about 2.5kHz).

With that said, here is what Dirac shows as the response from 13 measurements (top image) and from another, separate round of 7 measurements (bottom image). To be clear, these are the pre-correction responses.

View attachment 295978

View attachment 295979

Note not only the nonlinear response, but also that the scale is 10dB per vertical unit. According to Dirac, there's an 8dB dip at 5kHz compared to about 2.5Khz and about 7kHz. There's also about 4-5dB of nonlinearity at various points from the Schroeder frequency up to 1kHz.

This just seems awful - or am I expecting too much from a non-smoothed response graph of passive speakers with no built-in DSP?

Now, the speakers don't actually sound to me the way this curve suggests. But they don't necessarily sound quite right either. I don't even know exactly what Dirac is showing me here - is this an average of in-room response from all the measurements? Or has Dirac used those multiple measurements to calculate a quasi-gated or quasi-anechoic response curve for the speakers here? If I'm not supposed to use Dirac to flatten the response above about 300Hz, and I can't use these Dirac measurements as indicators of what my ears are actually hearing in-room, then how am I supposed to use PEQ to try to flatten the response?

Should I just give up and sell these speakers and get an active speaker with built-in DSP instead? I feel like I'm caught in a classic circle of confusion, no longer being able to tell with confidence if the tonality of my music is right or not, and seemingly having no dependable way to know how I should actually be EQ'ing these speakers above 300Hz for decently accurate response. I mean, can we simply not own speakers if they are too old to have spinorama data available?

As might be obvious from this post, I'm kind of at the end of my rope at this point. I feel I've tried my best here and I'm most definitely not having fun anymore at this point. I would be grateful for any perspective, guidance, advice, or helpful thoughts anyone can provide, to help me better understand what I'm looking at here and perhaps how I might come to an informed decision about continuing to work with these speakers versus giving up.

Thanks!

Im sure your speakers are fine.
My advice for you is to turn of Dirac completely and reinstall your speakers where they sound the best in your listeningroom. This will take you a couple of hours using Tunemethod (listening to the clearest bass pitch) with real music and the soundresult will be much better than any measurement microphone. Then, put a thick carpet on the floor infront of the speakers. This will tame the first reflected sound coming from the speaker which is very disturbing.
If you have sidewalls near the speakers , put some damping on those using a mirror on the wall when you are at listening position to see where the first reflection from the speaker is coming .

Roomcorrection is always done after proper setup of the speakers. Otherwise the sound result gonna be really bad. Only do corrections with Dirac below 300 Hz. Dirac cant fix a bad loudspeaker setup in the room.

 

[Chrispy]

Why would you expect these speakers to be particularly exemplary? There's probably a good reason they're no longer made/available....

 

[Mart68]

Why would you expect these speakers to be particularly exemplary? There's probably a good reason they're no longer made/available....

There doesn't appear to be any anechoic measurements of this speaker available on line so certainly possible that this is just how they are.

Too many variables to say for certain.

Personally if I get fed up trying to get a speaker to sound right I move it on or store it away. Plenty more fish in the sea.

 

[Chrispy]

There doesn't appear to be any anechoic measurements of this speaker available on line so certainly possible that this is just how they are.

Too many variables to say for certain.

Personally if I get fed up trying to get a speaker to sound right I move it on or store it away. Plenty more fish in the sea.

Just curious, no experience. Read a wide variety of comments/opinions. A pair came up for sale locally recently but wasn't tempted enough to go take the two hour drive for a listen....

 

[Mart68]

Just curious, no experience. Read a wide variety of comments/opinions. A pair came up for sale locally recently but wasn't tempted enough to go take the two hour drive for a listen....

I'm lucky I don''t have a car. If I did my house would be full of speakers, there's always some for sale that I am interested in, just too far away.

Sometimes the seller is happy to deliver them personally though so the stockpile slowly increases.

I have always wanted to try this particular Infinity since reading the review in about '89.

 

[tmtomh]

I'm lucky I don''t have a car. If I did my house would be full of speakers, there's always some for sale that I am interested in, just too far away.

Sometimes the seller is happy to deliver them personally though so the stockpile slowly increases.

I have always wanted to try this particular Infinity since reading the review in about '89.

They’re really great speakers, and unique - or at least distinctive for the price - in some of what they can do. Those 4x 12” woofers can move a lot of air and are crossed low, so they’re never boomy. And the soundstage height is very nice too.

The load they present to an amp is of course their most notorious issue, but they have a switch in the back that modestly reduces the bass and turns them into a pretty easy 4-ohm load (except for a dip to 1 ohm at 10k, but there’s so little energy there in most music that any load-independent amp can handle them).

IMHO their real thing for prospective owners is not the impedance but just the complicated nature of them: 5-way design, 7 drivers, 4 driver/crossover adjustment pots, “extended/normal” bass switch, decaying woofer surrounds, and polydome midranges that disintegrate and need to be refurbished or replaced. And they weigh 120lbs each.

For me these are all potential issues - but of course for others, these are interesting and really fun things to experiment and tinker with.

My pair has recently replaced woofer surrounds and a very nice replacement midrange (with the right impedance - some replacements are 8 ohm instead of the original 4 ohm). I never would have moved them into my place otherwise, as I’m not a DIYer when it comes to speakers. And they are beautiful looking speakers - vintage but IMHO a timeless look.

Shortly after my last previous post in this thread, I felt I was finally getting them closer to dialed in. But I also realized that it’s not just about figuring out the sound. It’s also about how one feels looking at fairly large (albeit svelte looking in this case) speakers all the time when listening; about how much one likes vintage gear, complexity, tinkering/experimenting, and so on. In my particular case, there’s the added factor that these were my father’s, who passed recently. Recently I have realized that my experience of packing these up, hauling them into my room, setting them up, learning Dirac to smooth the in-room response, and so on has been all tied up with the grieving process. I have many items of his in my space now, and they are cherished reminders, but at the end of the day I realized that something about having those two very large reminders of him in my room (and not his room where I’d experienced them for so long) just made me sad.

Sorry to go on, but I just wanted to explain why I think these speakers are so cool, but ultimately not for me. I have replaced them with actives and am quite happy so far. I am planning to sell the Kappas before the end of summer, but it will have to be to a local buyer for obvious reasons.

 

[fineMen]

The 5kHz dip might be a crossover issue, either a cap gone bad, or possibly the replacement driver not having the same impedance (but it should if it's intended specifically as a replacement).

Exactly. The speaker is exceptionally complex in its design and won't measure that good nearly everywhere due to inherent directivity issues in the vertical. The latter is really a challenge. To stick to 'on axis' first means to find that axis ;-) Only an inch beside it may wrinkle, wonder why the frequency curve doesnt entangle itself in loops ...

Bold and bad, but ... better give it to a DIYer if there is no sentiment attached to it.

 

[tmtomh]

Exactly. The speaker is exceptionally complex in its design and won't measure that good nearly everywhere due to inherent directivity issues in the vertical. The latter is really a challenge. To stick to 'on axis' first means to find that axis ;-) Only an inch beside it may wrinkle, wonder why the frequency curve doesnt entangle itself in loops ...

Bold and bad, but ... better give it to a DIYer if there is no sentiment attached to it.

Thanks! There's a good deal of sentiment in this case, but as noted in my prior post, the sentiment compelled me to try these out and play with them, but not necessarily to keep them.

Very good point about the directivity. I'm actually super-impressed with the treble of these speakers given that the tweeters are by definition never going to be vertically on-axis with a seated listening position (unless you're 7 feet tall or like to sit on a barstool to listen ). But yes, with 6 front-facing drivers and 1 rear-facing driver (and a rear-facing port for the midrange), all at different heights, and 4-5 of those drivers emitting sound at highly directional frequencies, there are bound to be nonlinearities and they are bound to be variable based on listening position, and as you say perhaps based on small changes in listening position.

That said, whether I took 3, 5, 9, or 13 measurements with Dirac, the frequency response graphs didn't vary a whole lot.