AES Journal Forum

Multichannel Sound Reproduction Quality Improves with Angular Separation of Direct and Reflected Sounds

(Subscribe to this discussion)

Document Thumbnail

Some researchers believe that the reproduction of multichannel spatial audio would be improved by using separate transducers for the direct and diffuse components of the sound. This research seeks to empirically test this assumption. The perceptual effect of angular separation in commonly used 5.0 and 7.0 multichannel systems was investigated. Four listening experiments were performed involving several schemes of separation and a variety of experimental conditions. The listeners consistently preferred schemes with separation. The perceptual effects of four types of management of direct and reflected parts of spatial impulse responses (SIR) were considered: using complete SIRs in all channels; removing the direct sound (DS) from all but the center channel in a standard 5.0 system; removing ambience from the center channel in a standard 5.0 system; applying both of the above operations (separating DS from reflected sounds RS in particular channels). Depending on the configuration, separation did in fact have advantages.

JAES Volume 63 Issue 6 pp. 427-442; June 2015
Publication Date:

Click to purchase paper as a non-member or you can login as an AES member to see more options.

(Comment on this paper)

Comments on this paper

Default Avatar
Philip Newell

Comment posted September 4, 2015 @ 19:06:31 UTC (Comment permalink)

On page 433 of the June edition of the AES Journal, in a paper called 'Improved Multichannel Sound Reproduction Quality', it says, 'The room met most of the ITU-R [BS.1116] criteria or has parameters very close to recommended. It meets the criteria for floor area and the ratio of dimensions. The RT is much shorter than the recommended 0.56 s.' On the previous page (432), the authors gave the size of their room as about 75 m3, with a floor area of about 26 m2 [3.9 m x 6.7 m x 2.8 m].

                    Surely there is no way that a BS.1116 room of 75 m3 would have an RT of 0.56 seconds. It would be more likely to be in the region of 0.2 seconds. (Or am I misreading something?)

                        Best wishes,


Piotr Kleczkowski
Author Response
Piotr Kleczkowski

Comment posted November 5, 2015 @ 17:30:57 UTC (Comment permalink)


We appreciate your comment. We are sorry for this mistake. The BS.1116 recommends that:

Tm = 0.25(V/V0)^1/3, where V is the volume of the room and V0   is the volume of the reference room (100 m3).

In our case this makes Tm = 0.23 s, very close to your assessment. Our measured RT20 was 0.15 s and we stated that in the paper, which I hope reduces the meaning of our mistake.

Best regards,




Default Avatar
Philip Newell

Comment posted November 7, 2015 @ 16:32:39 UTC (Comment permalink)

Dear Piotr,

                  OK; thank you for the clarification.


                               Best wishes,



Subscribe to this discussion

RSS Feed To be notified of new comments on this paper you can subscribe to this RSS feed. Forum users should login to see additional options.

Join this discussion!

If you would like to contribute to the discussion about this paper and are an AES member then you can login here:

If you are not yet an AES member and have something important to say about this paper then we urge you to join the AES today and make your voice heard. You can join online today by clicking here.

AES - Audio Engineering Society