Any point in running Kappa 9s with a Purifi 400 stereo amp?

[tmtomh]

The 7.2i's with the Scanspeak Discovery units have had a mod with an extra resistor it seems. As far as I remember when I got them and compared the crossovers. They are 8 ohm nominal units as opposed to the 4 ohm Polydome and they should also have way higher sensitivity hence the resistor. Should perhaps have been a higher value resistor because it does have an elevated mid-range frequency range in my measurements.

The 8.2i's are the ones with the Dynaudio D52's. And they measure flat with the knobs in center pos. No mod to the crossover. A drop-in replacement for the poly's and lauded by many to be better than the Polydomes.

Are you saying a Dynaudio D52 driver is a drop-in replacement for the Polydome in the late 1980s Kappa 8/9?

 

[tmtomh]

A quick update:

I've been playing with the L-pads and took some SPL meter measurements - nothing super-detailed or precise, just at the 10 octaves from 32Hz to 16kHz, doing a few runs to ensure the readings came up the same each time. Some of the readings surprised me, while others confirmed my listening impressions:

• In "normal" mode - which produces less low bass than "extended" mode - these suckers are F0 at 32Hz; in other words their SPL at 32Hz is the same as their SPL in most of the rest of the frequency range. Pretty nice! I tried enabling extended mode, but it either made no difference or added a little too much in-room bass (my comparison was sighted, so I don't know if my perception of too much bass was real or confirmation bias).
• There's a small increase in energy at 63Hz and a somewhat larger one at 125Hz. This was a surprise to me, as the speakers don't sound boomy to me, and I'm pretty sensitive to elevation in the 125-200Hz range. I am guessing these are room modes, and I will be very curious to find out what their Q is, becuase I'm guessing it's pretty high aka these modes are fairly narrow in frequency range, which is probably why they're not jumping out at me.
• There's a few dB elevation at 2 and 4kHz, which was not a surprise at all, and in fact kind of a relief, because this was exactly the range where I was sure I was hearing something that wasn't quite right. The original polydome mids disintegrated over the decades (super common problem with these), and my father replaced them with fabric domes that are a little more sensitive, so the L-pads are incapable of attenuating these replacements enough to get them to be flat with the other drivers.

So with this info in-hand, I've gone ahead and ordered a MiniDSP SHD, and when that arrives I'll put it between my Oppo 205 and my amp, and let Dirac take care of everything.

In the meantime, I've enabled the 10-band EQ built in to the Apple Music app on my Mac mini that I use as my music streamer, and dialed in 2-3dB cuts at 125Hz, 2k, and 4k. This is just a stop-gap until the SHD arrives, as it's a crude, incomplete solution, and it doesn't allow me to have the EQ when I play physical discs from the Oppo. But even this simple EQ'ing seems to have addressed the issues I was hearing, so I would guess the sound will only improve further after Dirac does a more fine-grained and extensive removal of nonlinearities that are influencing the sound now but which are not jumping out at me.

So I think once the SHD arrives and I get it all set, I'll be very happy with this setup and I could be set for the foreseeable future.

If after a couple of months there is anything that bothers me about them, though, at that point I'll feel satisfied that I've done the best I could do with them, and I'll sell them and get a pair of Genelec 8351s. But as of now I'm feeling pretty optimistic that these Kappas are going to suit me nicely.

 

[Deleted member 48726]

Yes, the Dynaudio should be drop-in replacement as far as I could find out. My crossover in the 8.2i's look original and nothing ugly shows up in measurements.

 

[tmtomh]

Yes, the Dynaudio should be drop-in replacement as far as I could find out. My crossover in the 8.2i's look original and nothing ugly shows up in measurements.

Thanks! Because I don't feel confident in my ability to do such a swap myself, and these speakers are nearly impossible to move, and the mid units are very recent replacements in great condition, I think I will just let the MiniDSP SHD smooth out the response, since I'm sure I'll need the SHD for room modes in the sub-300Hz range anyway. Appreciate the info though!

 

[Deleted member 48726]

Thanks! Because I don't feel confident in my ability to do such a swap myself, and these speakers are nearly impossible to move, and the mid units are very recent replacements in great condition, I think I will just let the MiniDSP SHD smooth out the response, since I'm sure I'll need the SHD for room modes in the sub-300Hz range anyway. Appreciate the info though!

Yeah. That worked with my 7.2i's nicely.