Bloom in sound from Summits

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Stereonerd

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I love my Summits, but am finding that there's something of a "bloom" somewhere in the mid-range that can make for some uncomfortable listening. No amount of fiddling with the bass loudness adjustments have any impact on this bloom. As there's no modern EQ available on the Summit I wondered if anyone had advice about this. I'm in a square room which isn't ideal but have found that other brands sound fine. Is the "bloom" likely to be fixed by some kind of room treatment?
 

JonFo

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I'm in a square room which isn't ideal but have found that other brands sound fine. Is the "bloom" likely to be fixed by some kind of room treatment?
Yep, the technical term for that is 'ringing', as these large dipoles (radiate equally front and rear) will cause modal ringing at frequencies dictated by room size, speaker placement, and room surface materials.

A square toom is indeed the worst shape from a modal perspective, although that is usually in the low-end, but will indeed affect midrange, as you report.

Yes, room treatments will easily fix the midrange and up issues.
I'd first start by reducing the rear-wave energy by placing absorbers (4" non-reflective, RealTraps MiniTraps HF or equivalent) offset from the wall behind by 2 to 3" such that they absorb (coefficient of 0.9 or better) from 300Hz on up. Place them in the line of fire from the rear of the panel, so if they are toed-in, the panels on the front wall will not be directly behind the speakers, but slightly outboard, centered with the direction the rear of the panel points at.

The next place to add treatments to mitigate that ringing will be the rear wall (behind the listener), so I'd also use non-reflective treatments 3 to 4" on the rear wall, covering the entire area behind the listening positions. Generally, an area 4' tall by 6 or 8' wide. post a drawing (hand-drawn is fine) of the room, the perforations (doors, windows, etc.), measurements, and locations of the speakers.

Since it's a cube, I'd also add some lateral absorption to mitigate ringing in that axis. So another pair of 2x4' 4" absorbers on the side walls behind the speakers (close to the front wall) is positioned to mitigate whatever 'bounce' from the rear wave might be coming off the front wall. Think billiards to find the right placement.

I'd also place some absorption on the side walls opposite the direction of travel from the front of the panels. In a cube, guessing that will be near the rear corners. If aiming at the corner, then the treatment would straddle the corner.

Do you have subs as well?
 

JonFo

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Do you own a measurement mic (e.g., UMIK-1 ) ?

If not, investing in one of those, plus a free copy of REW (available for MacOS and Windows 10) will greatly help you find and fix the exact issues your system has.
An audio measurement system is just as important to an effective system set up as a tape measure, a level and a square-edge are to a carpenter.
 

Stereonerd

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No, I don't have a sub at the present time. The Summit's bass goes plenty deep in this room, so it seemed unnecessary. Thanks for your advice, JonFo. It's all a bit mindboggling, but I'll investigate these options. Our main city (Auckland) is in Covid lockdown at the moment, so I'll have to wait (and see what the other half says about spending the $$ on panels).
 

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Don't know where your bass setting are but I'm in a near as damn square room (13'x14') and a suspended wooden floor. I have my Summits on 350mm x 550mm x 30mm marble slabs, 3' out from media racks (lp & cd) and centreline to sidewalls 2', speakers are 8' apart centre to centre. My bass settings are 25hz - 3.5, 50hz - 4.5, bass, is tight, weighty with real, punch & no boominess. Midrange up is rich, clean and clear with delicacy and sparkle at the top.
 
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Stereonerd

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Don't know where your bass setting are but I'm in a near as damn square room (13'x14') and a suspended wooden floor. I have my Summits on 350mm x 550mm x 30mm marble slabs, 3' out from media racks (lp & cd) and centreline to sidewalls 2', speakers are 8' apart centre to centre. My bass settings are 25hz - 3.5, 50hz - 4.5, bass, is tight, weighty with real, punch & no boominess. Midrange up is rich, clean and clear with delicacy and sparkle at the top.
Thanks for that. I've got both my bass settings at -4 but I find that the "bloom" I describe doesn't seem to relate to the bass at all, just the deeper/richer mids, which as you describe is "rich, clean and clear" but in my case, can be overwhelming. I'm looking at tracking down some marble slabs as like you, I have a suspended wooden floor that could be the seat of all my problems!
 

Lurch

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I must admit when I first got mine I set the 25 lower than the 50 thinking the sub bass would be the frequency to give me grief. However swapping them round so the 50 was attenuated more than the 25 opened and cleaned up the mid & treble + gave more weight and tightness to the bass, go figure.
As for the marble slabs I visited a local stone masons/kitchen worktop firm and they gave me a choice of colour and cut them for me.
 

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Thanks for that. I've got both my bass settings at -4 but I find that the "bloom" I describe doesn't seem to relate to the bass at all, just the deeper/richer mids, which as you describe is "rich, clean and clear" but in my case, can be overwhelming. I'm looking at tracking down some marble slabs as like you, I have a suspended wooden floor that could be the seat of all my problems!
In addition to slabs, I also installed floor jacks below the area where the speakers are situated using pieces of 4 x 4 to bridge several floor joists. Obviously this treatment might not be doable depending on what is below the sound room.
 

Stereonerd

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In addition to slabs, I also installed floor jacks below the area where the speakers are situated using pieces of 4 x 4 to bridge several floor joists. Obviously this treatment might not be doable depending on what is below the sound room.
Actually, I think my definition of "suspended floor" was wrong, having just Googled it. My listening room is actually above the garage, and I don't think the flooring is very solid, hence a kind of hollowness. Maybe the whole floor ultimately needs reinforcing/bracing. But in the meantime, I'll certainly try the marble slab approach. Currently, I have my Summits on wooden chopping blocks which do help but don't entirely fix the problem. I've considered buying expensive isolation feet but don't have the cash - two expensive wee mouths to feed. What I've been doing over the past week is making small adjustments to both speaker and seating position and the mid-"bloom" is about 50 percent better than it was. It's amazing how much positioning impacts on the Summits. I've brought them further into the room and moved my seating position back closer to the wall, and suddenly the whole sonic "picture" is magic!
 

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My floor is not suspended (hardwood on concrete), but when I first moved in, I got a couple of larger terracotta-looking pavers from Home Deport - 16" X 16". Not as weighty as yeah ol' marble slabs, but throw-away-cheap to test the theory!

Russ
 

audioxcel

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Actually, I think my definition of "suspended floor" was wrong, having just Googled it. My listening room is actually above the garage, and I don't think the flooring is very solid, hence a kind of hollowness. Maybe the whole floor ultimately needs reinforcing/bracing. But in the meantime, I'll certainly try the marble slab approach. Currently, I have my Summits on wooden chopping blocks which do help but don't entirely fix the problem. I've considered buying expensive isolation feet but don't have the cash - two expensive wee mouths to feed. What I've been doing over the past week is making small adjustments to both speaker and seating position and the mid-"bloom" is about 50 percent better than it was. It's amazing how much positioning impacts on the Summits. I've brought them further into the room and moved my seating position back closer to the wall, and suddenly the whole sonic "picture" is magic!
Yeah, I suspect your problem is more related to room resonances than floor structure. I have had original Sequels since they were first released (almost 35 years ago). In that time I have moved 6 times and had small rooms to large rooms with floors that were concrete slab and wood on joists (crawl space and 2nd floor).

The best sound I have had was in a second story room that was large 16'x24'. The back wall was all windows with blinds that I used as diffusers but I don't see why blinds could not be used on a solid wall. I have always been able to tease good sound out of any of the rooms even the smallest at 12'x15' with positioning and room treatments using decorating pillows and wall coverings (blankets, curtains, etc).

I have always used the originals spikes (just to prevent movement).
 

Stereonerd

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Yeah, I suspect your problem is more related to room resonances than floor structure. I have had original Sequels since they were first released (almost 35 years ago). In that time I have moved 6 times and had small rooms to large rooms with floors that were concrete slab and wood on joists (crawl space and 2nd floor).

The best sound I have had was in a second story room that was large 16'x24'. The back wall was all windows with blinds that I used as diffusers but I don't see why blinds could not be used on a solid wall. I have always been able to tease good sound out of any of the rooms even the smallest at 12'x15' with positioning and room treatments using decorating pillows and wall coverings (blankets, curtains, etc).

I have always used the originals spikes (just to prevent movement).
Thanks. Well, I certainly have no problem with the top end - it's not overly bright at all - so putting cushions and other soft furnishings on or around the walls... wouldn't that just make the top end sound muffled? I've auditioned several conventional speakers in this room (GoldenEar Tritons, ProAc, NZ brand Theophany) and they all sounded great despite the room being almost square. It's just the MLs I have this "bloom" with. But as I said, it's much improved since I moved my listening position back and the speakers further out into the room.
 
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