Room treatment advice needed


I have a pair of Yamaha NS-1000x as mains in my primary listening room, and I love them so much I bought a second pair for my office. The new pair is a gorgeous rare walnut cabinet and the drivers are pristine without blemishes. A very lucky find that I treasure. I tried them with my original equipment in my main room, and they are wonderful. However, the new pair sounds awful: super-detailed, as expected, but thin, trebly, no bass, no imaging at all, in my office.

My office is small (I'm in Japan), less than 3X4 meters. It has a hard wall on one side, but that side has my work desk and computer. The other three walls are composed of thin sliding doors made of plexiglass.

The floor is of firm wood, covered by a carpet.

The Yamahas are currently on brass cones on granite slabs over cement blocks. I have put blotches of blue tac between the stone slabs.

I know these large, heavy speakers are huge overkill for such a small room, but I want to make them work (or face a serious marriage crisis...) there. I am wondering what should be my first aim in room treatment, and hope for the advice of this boards' minds.

What comes to my mind first is thick curtains to cover the plexiglass sliding door/walls, hopefully reducing lots of high-end reflections. Do you guys agree with that?

What other steps should I take?

Main source/amp is flac files fed from iMac or Wav from iPod through an iDecco. I also sometimes bring in my Luxman amp and Njoe Tjoeb CD player instead, from my main room. Wonderful sounds in the main room, but no magic in the office in either case.

On the other hand, the iMac/iDecco combination sounds rich, full, warm, and detailed through a pair of Quad 12L's on my desktop. These are placed with the rear-port bass outlets facing the hard wall. They are on small granite slabs on my computer desk on either side of a 27-inch iMac, with blue tac between slabs and desk and slabs and speaker. They are in a near-field listening position, meaning that I hear mainly the unreflected sound from them, as opposed to my Yamahas (behind me while I work), from which many reflections reach my ears together with the direct speaker sound.

Please freely offer advice on getting the best sounds out of my Yamahas that they are capable of in this small, plexiglass-walled office space. I will greatly appreciate your opinions.
deaf_in_left_eye
As you noted, thick curtains would help reduce high frequency reflections. The curtains, however, will not help with mid and low frequencies. It may be that the high frequency reflections are what you notice the most now, but when the high frequency reflections get reduced, you may discover that you have other issues going on in the low and mid frequencies. I suspect that you do in a room like that.

One thought is to consider broadband absorption panels, like the GIK Acoustics 244. The idea of broadband absorption is that it is absorping a very large range of frequencies, with the idea of smoothing out the frequency range in the room. Any room has peaks and dips at certain frequencies just based on physics and room dimensions (and it sounds like you have lots of extra reflections going on). The 244s can be hung on the wall, but they also make stands to place them on which may make more sense if three of the walls are sliding doors (that is, so you can move them when you need to).

I was amazed out how much the GIK 244s did for the sound in my room -- for example, I realized I was not hearing all the notes (bass notes, as well as higher frequency notes), voice became much clearer and focused, and everything sounded more natural.

The folks at GIK Acoustics are very helpful and you can email them room dimensions and pictures and get a free recommendation. There are other companies that sell similar products, but I mention GIK because I had a very good experience with them, their prices are very reasonable, and I received very good service.

Depending on how the sliding doors work, you may also consider broadband absorption/bass trapping in the corners. The post above mentions triangles in the corner. You can also do something like a GIK Tri-Trap. Also, if you like the idea of do it yourself, the Gearslutz forcum (under bass trapping, room acoustics) has lots of info on DIY corner traps and other DIY room treatments.

I found that Ready Acoustics were very helpful and had good prices. If you will send them a photo of your room they will make suggestions. Totally transformed my room.
Thanks Holenneck, Chazzbo, Edge22, Stanwall
Holenneck:
"One set of treatments at a time" is great advice.
the first thing I've done so far is to get some test wave files to play various frequencies in steps from about 16Hz to 18kHz to find out what is happening over the spectrum. I found certain spots where all the bass is trapped behind the speakers, others that rattle the plexiglass sliding doors, and even some that I can hear loudly with my ears pointing one way and almost not at all in another.
I'm going to replay these wave files, along with very familiar music over a wide range of styles, between each "set of treatments," on your advice.

Chazzbo
Three of the entire "walls" are just plexiglass sliding doors in light wooden frames. Its a modern-ish room built-on to an ancient Japanese house. Thus, the Yamahas are not near any walls at all. there is a good eight feet to a cement wall behind them, across a hallway behind plexiglass. The only solid wall in this room is where the desk, computer, and Quads are. That can't be changed.

I am looking for "thick carpet"-like objects to try behind the Yamahas as my first big room tweak. I'll start with woolish blankets and move progressively thicker up to some old futons (real Japanese futons are like 2-inch thick blankets, sort of, not like what they call futons in North America).

I wish I had time to read a whole book on the subject, as you recommend, but I'm a super-busy guy most of the year.

Edge22
I'll try blankets over the plexiglass on the sides first to simulate curtains and see how it sounds, after first trying the above stuff to sort out the bass.

As I'm in Japan, and on a budget (Thus the Yamahas rather than JM Utopias or SF Stradi Homage or something...), so pro service or materials would be logistically impossible and economically beyond my means. I'll look into your and Holenneck's suggestions about corner treatment, a la DYO.

Stanwal
Thanks for the tip, but as above I'm not in North America right now.

Meantime, there are some movable bookshelves and some big storage boxes in this small room to try moving around, too. No other space to put them in, can only shift them inside here somehow...

If anybody out there thinks of some other tips, I'm all ears!

Thanks again, all. This is a fun and interesting challenge.
Before experimenting with room treatment I recommend you restore your speaker's tonal balance by removing the brass cones, granite slabs, cement blocks and blue tack.

It is a good idea to research what cables were popular when your speaker was manufactured. Sometimes the newer cables do not work well with older equipment.

Try tilting the speaker back with it resting on the floor. Very small changes in the tilt angle can make a big difference in the sound.
Rrog - Thanks! That sounds like rational advice. I was just about to start moving stuff around. I'll try taking them off the blocks, etc, first. As for cables, I have another set of these speakers in another room, where they sound great. I'll try switching cables with the ones in that room, to see if that makes an improvement.