Elevating my Poang Listening Chair
My stereo listening chair is an inexpensive Ikea Poang chair. It's comfortable enough, but the seat is positioned too low for the best sound from my tall loudspeakers. In addition, I am only 5' 7" tall. When I built the LX521 loudspeakers, I temporarily placed the speakers on wheeled dollies to experiment with their lateral position and toe-in. The dollies raised the speakers about 2" from the floor, putting the tweeter well above my ear height.
In this temporary elevated state, I noticed that the sound deteriorated compared to my initial listening arrangement (speakers on the floor). I assumed that the extra speaker height was causing what I heard. It sounded as if the performer was a little too close the microphone, a bit "chesty", and that reduced the illusion of someone actually performing in the room. During the speaker positioning experiments, I temporarily placed some scrap lumber under the chair to lift it about the same amount as the speakers on the dollies. This was in place only while I adjusted toe-in and position for a good soundstage. It helped raise me to the speaker's vertical design axis, and improved the sound.
The speaker dollies were just temporary, and are now gone. The sound did improve when the speakers returned to the floor after placement experiments. However I was now aware of the influence of listening height. In the low Poang chair, I noticed that my ear level was still below the design axis even with the speakers resting on the floor. My ears were level with the center of the lower midrange driver, not the upper mid or tweeter as specified by the designer. I experimented with listening height by raising and lowering myself in the chair while listening to female vocals. This simple experiment showed that an elevation of a few inches was sufficient to improve the sound noticeably.
Because I sit fairly close to the speaker (~7 feet), the listening-height problem is apparently aggravated. Listening from further away reduced the problem. I assume that was because all the drivers were integrating better at further distances. Because of my room arrangement, a more distant seating position was not practical.
I'm not going to get any taller, so I did two things to elevate the chair's seating position to improve sound. First, I purchased an inexpensive foam cushion from a Jo-Ann Fabrics store to go under the chair cushion. Second, I made some "feet" for the bottom of the chair to lift it an extra 1-1/2" from the floor. This picture shows both in place.
The foam pad from Jo-Ann Fabrics was placed beneath the chair's existing seat pad. It measured 17" x 15" x 3" uncompressed, so the actual lift is less with someone seated.
Next, I made some feet that raised the entire chair frame another 1-1/2". They were fabricated from some leftover 2x4 pine, and some 1/8" Masonite. Nominal 2x4 material is actually 1-1/2" thick, not 2", so that determined the extra height I'd get by using it.
The 2x4 lumber was ripped on the tablesaw to match the width of the chair's leg (~2.45"), and then crosscut to make 4" long pieces. Strips of Masonite were ripped to 2.65". The short Masonite side pieces for accommodating the chair's crossbar were crosscut to be 1" and 1/2" wide. The clearance hole for the connector bolt was 3/4" diameter.
The rear of the chair leg included a cross-beam and a connector bolt. Fortunately, that arrangement made attaching the rear pads a snap-on affair. They remain in place by themselves when the chair is lifted or moved. The front pads were affixed using adhesive-backed Velcro between the chair and the pad. No irreversible changes to the chair itself were necessary.
While the improved seating position is still somewhat lower than ideal, any further raising of the chair will not allow me to place my feet flat on the floor. This is about as high as I can go without modifying the angle of the seat and backrest.
It does provide a noticeable improvement in sound though. Sitting too low with my LX521 speakers was the cause of a very slight "chestiness" in vocals, especially female vocals. This modification cleans up that problem, and positions me closer to the loudspeaker designer's listening-axis specification.
This experiment also makes me wonder if my previous Plutos would have sounded any different with this taller chair. I recall sitting a little below the midwoofer level when they were the loudspeakers that I used in this room. They too may have shown an improvement.