Combining Genelec 8351b with Linkwitz open-baffle bass module

[suttondesign]

Hi All,

By way of background, some years back, before he died, Siegfried Linkwitz ruminated that one of the new breed of well-engineered speakers like the Kii could work well -- even in comparison with Siegfried's LX521 -- if combined with an open-baffle woofer like the one he designed for the LX521. I've been running Linkwitz LX521 for some years. As my posts over the years have suggested, the LX521 don't have the buttery response smoothness of Dutch, Kii, Genelec, and Neumann. The LX521's strengths are its imaging and sound field. But even there, the horizontal and vertical dispersion patterns don't have the remarkable consistency that the Genelecs have in that respect. (It seems to me that only the Genelec Ones and the KEF Blades have such similar horizontal and vertical dispersion patterns).

This has practical consequences for me, and please don't hurl insults at me when I say this (yes, I do get snarky comments when I mention in some places how I use the LX521 in impure ways). I only have the one main system now, in our main living room, and it does double-duty for movies and music. Family members share in the bounty, but the LX521 do not play nice with dialogue because of the way they are designed to interact with the room and recess the sound field. And they really don't work well for a couple of the listening positions on either side. In sum, mine is not a single-spot listening room for me alone.

So! I'm am considering, just for fun, having the option of placing Genelec 8351b's on top of the LX521 bass module. (Easy to do in my setup for reasons I'll spare you).

Does anyone have a helpful suggestion about integrating the 8351b with the open-baffle modules, which have 2-each of the SEAS L26RO4Y 10" drivers? I use MiniDSP digital crossovers, so it's easy to manipulate things. The LX521's cross over down low at 120hz with a 4th-order Linkwitz-Reilly filter. (I high-pass these to big sealed subs to avoid bottoming-out in movies). Seems like I could just use the same crossover point, high-pass the Genelecs with 4th-order LR, and find the right level using REW.

 

[AudioJester]

Interesting idea. Are you trying to smooth bass response or increase SPL.

I actually think the 8351b may allready have better bass performance than the Lx bass bins.

 

[suttondesign]

smooth response. but i don’t want the kind of bass produced by a box. i prefer the more natural open baffle bass. and i already have big dual-opposed subs operating below 35hz.

 

[ShadowFiend]

@suttondesign : I like your idea but implementation is a big problem. The problem is that the radiation patterns of those two are very difficult to combine. You can easily integrate your subs and LX521 since at your crossover point 35Hz, the dipole subs of LX521 likely looses their ability to pressure the room due to the room size. But when you try to mix dipole subs of LX521 with Genelec 8351b at 100Hz, their radiation pattern will be a mess to work with.

I think it will be easier when you cross the 8351b to your big dual-opposed subs at 80 Hz.

 

[AudioJester]

The Lx bass bins can go much higher, even upto 400-500Hz.
If you are using them purely to smooth bass resonse, that is still running the 8351b down to sub crossover 35Hz (damn thats low!), could be interesting. The many bass sources approach, i guess they are easy to position around the room.
You may prefer the bass bins because of reduced room interaction, but I would have thought GLM would even that out?

 

[phoenixdogfan]

Hi All,

By way of background, some years back, before he died, Siegfried Linkwitz ruminated that one of the new breed of well-engineered speakers like the Kii could work well -- even in comparison with Siegfried's LX521 -- if combined with an open-baffle woofer like the one he designed for the LX521. I've been running Linkwitz LX521 for some years. As my posts over the years have suggested, the LX521 don't have the buttery response smoothness of Dutch, Kii, Genelec, and Neumann. The LX521's strengths are its imaging and sound field. But even there, the horizontal and vertical dispersion patterns don't have the remarkable consistency that the Genelecs have in that respect. (It seems to me that only the Genelec Ones and the KEF Blades have such similar horizontal and vertical dispersion patterns).

This has practical consequences for me, and please don't hurl insults at me when I say this (yes, I do get snarky comments when I mention in some places how I use the LX521 in impure ways). I only have the one main system now, in our main living room, and it does double-duty for movies and music. Family members share in the bounty, but the LX521 do not play nice with dialogue because of the way they are designed to interact with the room and recess the sound field. And they really don't work well for a couple of the listening positions on either side. In sum, mine is not a single-spot listening room for me alone.

So! I'm am considering, just for fun, having the option of placing Genelec 8351b's on top of the LX521 bass module. (Easy to do in my setup for reasons I'll spare you).

Does anyone have a helpful suggestion about integrating the 8351b with the open-baffle modules, which have 2-each of the SEAS L26RO4Y 10" drivers? I use MiniDSP digital crossovers, so it's easy to manipulate things. The LX521's cross over down low at 120hz with a 4th-order Linkwitz-Reilly filter. (I high-pass these to big sealed subs to avoid bottoming-out in movies). Seems like I could just use the same crossover point, high-pass the Genelecs with 4th-order LR, and find the right level using REW.

How about Dirac DLBC.

 

[ooheadsoo]

The W371A seems to be the more natural bass bin pairing so that you can manage that transition and also get cardioid bass.

 

[suttondesign]

@suttondesign : I like your idea but implementation is a big problem. The problem is that the radiation patterns of those two are very difficult to combine. You can easily integrate your subs and LX521 since at your crossover point 35Hz, the dipole subs of LX521 likely looses their ability to pressure the room due to the room size. But when you try to mix dipole subs of LX521 with Genelec 8351b at 100Hz, their radiation pattern will be a mess to work with.

I think it will be easier when you cross the 8351b to your big dual-opposed subs at 80 Hz.

I'm not following this. The 8351b are omni around the 100hz mark. I assume the LX521 bass modules are too by the nature of bass reproduction. Am I wrong? I do want to preserve use of the LX521 bass modules because of the distinct sound quality. And recall, too, that they can be rotated to any angle relative to whatever sits on top of them, which helps with room modes. So I guess the question is, why is a sealed or vented box better for integrating around 100hz if bass is omni no matter what kind of enclosure is used? (I doubt that my LX521 bass modules present a different phase issue than a sealed box, but maybe I'm wrong there too.)

So, yes, it's easier to integrate my big sealed subs, and visually that's quite appealing, but it's not consistent with my original goals.

 

[Doenerkunde]

In Germany there is an engineer named Axel Ridtahler, that developed a dipole subwoofer configuration called ripole that is somewhat close to the Linkwitz sub design. They are regularely paired with "conventional" non dipole speakers. Maybe you are able to find experience values for the Ripole that translate to your LX521 bass modules. Good luck!

 

[AudioJester]

So are you not happy with 8351b bass performance with GLM? Are you able to share GLM measurements?

 

[suttondesign]

I don't have the 8351b yet, but I've had many box speakers over the past 35 years, including the Dutch 8C within the past year (I was a dealer) and I very strongly prefer the open-baffle bass approach of the LX521. The Dutch 8C go very deep and very loud, but it still sounds like bass from a sealed box. That's what I don't want in the 35-120hz (or somewhat higher) region.

 

[AudioJester]

You can address some aspects with DSP, but personal preference is just that. Is it open baffle or dipole or both you prefer? Surprised you did not like the cardioid response of the 8c - to me, it leaves my Lx521 for dead!

The miniDSP should allow setting it up. If you are doing this the 8341 maybe a better choice than the 8351, saves a bit of money as well. Do you have some sort of platform/bridge for the bigger speakers on the bass bins?

 

[suttondesign]

whatever the lx521 bass module is called, that is what I prefer!

In my new home, I deleted the bridge atop the bass module. the upper module sits on it with some sorbothane between the two. I plan to build a more visually-friendly bridge at some point.

yes, the 8341 may be okay, as you suggest.