Adding to the mass and rigidity of a Belle Klipsch (?)

[garyrc]

My black Belle center channel seems to have a slight resonance or"woody" sound on certain male speaking voices in movies. I have never heard any kind of resonance in music reproduction. Soooo...... I am thinking of attaching some good 3/4 plywood to each side of the bass bin, as well as underneath within the inside perimiter of the toe-kick, and on the back. This won't make it an eyesore, because it is set into the wall, flush mounted, with grille cloth covering the opening. I have read very positive reviews of the new La Scala (III), attributed to the added thickness, rigidity and mass of its walls, so that's what I would be going for.

• Do you think this would help?
• I would screw and glue the ply panels on. Should the screws be just long enough to almost completely penetrate the inside of the walls of the Belle, or should they be longer -- enough to actually penetrate those original Belle walls, so they can be tightened up to the degree they put lots pf pressure on both pieces of wood?
• Any recommendations as to glue? Would a light sanding of the outside of the Belle bass bin be enough, or do I have to completely strip all the black paint off for the glue to stick properly?
• Does anyone have a drawing of the interior of the Belle to help me avoid hitting anything (especially the woofer)?

[JL Sargent]

The next time you notice this problem place a stack of books or something else on top of the speaker if possible. By doing so you will be adding mass to the speaker. This will in turn LOWER the natural freq. of the speaker. Maybe it will reduce or remove the resonance that you hear. I have belles and have never noticed the problem you describe but I'm not using them as centers either.

[WMcD]

I can't agree with anything which would deface a Belle. They are just too beautiful -- even if you hide them in a wall.

I can't see how the bottom of the bass bin could resonate. The dog house prevents movement, and I'll say the same for the top of the bass bin. Further, regarding the bottom, the hatch cover doubles up the thickness. As I recall, resistace to bending goes up as the 4th power of thickness. The back just can't be moving. The ramps for the initial flare make it very stiff.

Granted, someone out there may point out that these reinforments create smaller areas which resonate at a higher freq. None the less, they also stop the edges of any structure from bending in oscillation. So I can't see the argument.

The side pieces, we could talk about. The sides of the Belle are about 18 inches deep, whereas the LS is 24 inches. That smaller dimension in the Belle should cut down on the length of an "unsupported span" and thus I'd think it has less of an issue with resonance.

Let me suggest the following if you want to damp the sides: Build a four sided box of mdf (pretty well damped itself) so that it is about 1/4 inch overall larger than the Belle on the sides. Then insert or build in some foam or shims or something in the space between. You might fashion some mechanical attachment at the front of the panels if you wish.

But put a screw into the Belle? Never.

Let me agree with JLS here and restate my credo. You can't make things better by solving a problem which does not exist. Please determine first what the exact problem is. JLS has some good suggestions.

WMcD

[Islander]

I agree with both comments. See what the problem is before doing something to those speakers that you can't undo. I've used a Belle as a centre channel for a couple of years, and male and female vocals sound just fine.

Maybe there's something near the speaker that's modifying its sound, or causing its own resonance that seems to be coming from the speaker. Maybe there's an issue with the electronics.

I can't recall anyone on the forum ever feeling the need to modify a Belle cabinet.

[Taz]

The next time you notice this problem place a stack of books or something else on top of the speaker if possible. By doing so you will be adding mass to the speaker. This will in turn LOWER the natural freq. of the speaker. Maybe it will reduce or remove the resonance that you hear. I have belles and have never noticed the problem you describe but I'm not using them as centers either.

Another thought might be to turn the Belles on their sides and then load with weight to see if problem resolves

[pzannucci]

It could simply do with the loading since the speaker is not out in the free field. It is set into the wall which may mean proximity issues that many times are resolved by slight crossover mods fir equalization.

Does the Belle sound this way when it is out of the wall?

[Mighty Favog]

It could simply do with the loading since the speaker is not out in the free field.

I'm going along with this one. It could be that you're taking the 1/2 or even 1/3 spacing out of the mix.

[garyrc]

Thanks everyone!

The Belle sounds very much the same whether it is in the wall flush mounted, or in the room agaist a wall. The biggest difference is there is a slight boost in lower bass (maybe 50 to 70 Hz -- especially 60 Hz with test tones) when it is flush mounted. The resonance I'm hearing on a very few male speaking voices (the late John Spencer on West Wing comes to mind) seems to be higher than this, maybe centered on about 100 Hz

The Belle has a very little clearence on the left and right side of the bass bin, We have that stuffed with Sonex ,,, what would think of us taking the Sonex out and putting some specially milled boards covered with closed cell neoprene that we could wedge in on either side of the Belle bass bin to put some damping pressure on the sides, but leaving the top, bottom and back alone, for all the reasons Gil said?

[Quiet_Hollow]

Modify your sub settings. Play the troublesome voice with the sub turned off. Don't forget to take into account the source either. If it's just one particular voice from a specific movie or series, it could very-well be mixed poorly. There's nothing wrong with the stock Belle's ability to cleanly resolve the male voice in of itself.

[Quiet_Hollow]

Male voices should be as clean or cleaner than @ 5:47 and it's all dependent upon getting the mains and subs in phase and crossed over just right. In this case, 80Hz @ 18dB/oct

[garyrc]

Male voices should be as clean or cleaner than @ 5:47 and it's all dependent upon getting the mains and subs in phase and crossed over just right. In this case, 80Hz @ 18dB/oct

Male voices should be as clean or cleaner than @ 5:47 and it's all dependent upon getting the mains and subs in phase and crossed over just right. In this case, 80Hz @ 18dB/oct

Thanks.

@5.47???? I'm not sure what this means.

I've been crossing over at 40 Hz, in order to retain the clean impact of the Klipschorns above 40 Hz, compared to the RSW15 sub. My Belle is great at 60 Hz, then rolls of cleanly below. I have been considering raising the crosover to the standard 80 Hz, partly to protect the Klhorns from damage from increasingly louder ~~~ 20Hz signals in the new crop of movies. My only reservations about doing that are 1) losing the clean impact of the Khorns in the moderately deep bass ... but I gather that the primary percussive impact is from about 80 to 200 (true?) 2) If my R & L front power amp (NAD 272, for fronts) is deprived of the deeper bass, will it be operating at very low wattage output into speakers as efficient as the Khorns, and thus be operating at a small fraction of a watt for soft and moderate sounds, and be in a zone of higher distortion? I have never seen the data on that with the NAD 272, but I know some amps perform poorly at very low outputs. Or was this just true in the earlier days of solid state?

[Quiet_Hollow]

@5.47???? I'm not sure what this means.

It means watch the youtube video and skip to 5:47 on the timeline. At that point in the clip there will be some male dialogue to listen to on the LaScalas. Captain Pike's voice dips well into the sub's passband during this scene.