Arcs or Obs?

Have been listening to Arcs alongside ATC 35 for half a day. The largest difference re. freq. response: Arcs have a 5dB hump at 8-15kHz in my room ( and distinct metallic zing), whereas ATC are flat.
Do you think a room treatment can help here? What kind of room treatment would help?

(It does not mean that other than that they are similar, in fact they are strikingly different in all possible aspects, I will try to write about it in more detail later, if anyone is interested.)

BTW I tried TacT correction briefly - major difference is actually in the bass where ACTs are amazingly robust and able to correct 6dB and even 8 dB dips with no problems at all, whereas Shahinians start to distort immediatly. But this fragility pays - to my ears Shahs are more palpable and engaging dynamically whereas ATC are more powerful.

 

I think some diffusors are in order for this job. As always, the first reflection points will be the most important area to treat.

The sound reflecting from these points will likely be too soon after the direct sound from the speakers for your mind to tell any difference between the two. They seem to 'add up' over the frequency range you say. You will also find they cancel out at other points probably making the apparent peak worse.

If you treat these points so reflections take a much more complex path and are diffused into many lower level reflections, then the peak will be greatly diminished and cancellations will be filled in (provided that’s what your speakers are actually like!).

 

Tenson: as you can see here

(read Arcs instead of Obs)

with an open door to the right I have no first reflections apart from the fireplace left to my listening position. I have covered it with a large panel, about 4' fiberglass wrapped in a non-reflecting fabric (on a wooden frame, just passed WAF test) so at least here it is sorted. I guess I just need to tame the ambience a bit, since my walls are quite empty. I need to figure out what kind of treatment works in 8-15 kHz range, as anything lower is more or less OK and I don't want to overdampen it.

 

I think there are still a number of first reflection points. Behind the speakers, on the ceiling and on the wall behind you. There are probably some on the side walls as well because the speakers are not placed symmetrically. Have you checked to see where the side wall reflections are or are you just guessing they will be around where the fireplace and door are? It looks about right but sometimes it is not quite where you might think.

For frequencies above 8KHz use foam 2cm deep or less (if it deadens too much make it thinner), flat against the wall. Actually at this sort of frequency you can get away with pretty much anything that is fairly soft and absorptive. A thick curtain or a rug hung on the wall.

 

Walls both behind the speakers and the listener are covered by thick curtains, almost completely, because there are windows on both walls. Plus wooden blinds on windows, behind curtains, so I have a choice of diffusion/absorbtion here. Re side reflections - I have checked it with a mirror it's door and fireplace.

 

With both back and front walls 'almost completely' covered with thick curtain I would expect the room sounds pretty dead as it is at that sort of frequency. What is the floor like?

 

I would choose Vandersteen 3, Quattro or Cadence Arca if one is allowed to choose outside of the original posting

 

Tension,
my room does not sound dead at all because both side walls are pretty empty and reflective (I like it this way, it creates a spacious sound) and if I need a more lively room I can always leave curtains open and use my wooden blinds as diffusors, and the floor is oak with a carpet in front of the speakers. And my ceiling has some diffusive qualities, so the room is not that bad I can't make it more regular shape though.

 

Hi,

What do you get if you do a close up measurement of the speakers? I am wondering if it is the room at all, or the speakers. That way you can see if it is something you can fix by treating the room.

If you have a carpet in front of the speakers and a very absorptive front and back wall I would expect the room to be pretty dead in that frequency range. It may not sound dead though because lower frequency reflections, say, 1KHz-8KHz would not be absorbed very much. I'm just making a guess, because two walls and a floor is actually a lot of absorption.

Once we know if it is indeed the room, then we can start to locate the problem area. I would think in that case it is probably the ceiling as it seems that the only surface not treated in some form. Can you expand on what you meant by diffusive qualities?