|
Speaker Asylum General speaker questions for audio and home theater. |
|
|
|
Speaker Asylum General speaker questions for audio and home theater. |
|
In Reply to: Off-axis response posted by grblgrbl on July 24, 2002 at 06:58:22:
Some tests are more exhaustive than others. I have the Hi-fi News tests reports by the way. Off-axis problems in the upper crossover of the N801 are noted (this was not the case with the N802). Each model must be slightly different in terms of implementation of the upper crossover. Yet, the problem seems to be a consistent theme in every N800 speaker with the exception of the N802. Sometimes reviewers spot it (especially if they conduct extensive off-axis testing). Sometimes not.The problem afflicts both horizontal and vertical dispersion, but seems most severe in the vertical plane. The vertical dispersion of these designs seems unusually narrow (or at least the arc of coherent frequency response seems unusually narrow). Note Stereophile's published measurements of the N801; particularly figure 6 (horizontal dispersion) and figure 7 (vertical dispersion). Figure 6 shows deep cancellation notches centered at 3 kHz as you move off the reference axis, followed by a power "flare" at 6 kHz, followed by deep cancellation notches at 13 kHz as you move off the reference axis.
Stereophile comment on the vertical dispersion in fig. 7, "Fig.7, which shows the changes in the B&W's response in the vertical plane, normalized to the tweeter-axis curve, reveals that as long as the listener sits with his or her ears between the tweeter axis and the midrange axis, the perceived balance will not change too much. But if you sit so you can see the top of the speaker, or---horrors---stand up, a deep suckout appears at the upper crossover frequency (indicated in this graph by the cursor). This lack of vertically off-axis energy in the presence region might also lead to the speaker's reverberant energy being too politely balanced."
It's my contention that these "changes" in response relative to the reference axis create the synthetic sound (lacking natural timbre) of the Nautilus speakers. The suckouts and peaks are not devastating problems in and off themselves, as long as the tonal balance of the off-axis sound remains the same as that of the on-axis sound. The N800 series speakers do not, however, achieve this kind of even power response. The "changes" in tonal balance with listening angle destroy the illusion of accurate timbre.
By the way, I "measured" all of these problems just by listening to the speakers. At first it registered as a general, "something is not right about the sound," but over time it's easy to pin-point that the problem occurs at the upper crossover point. Furthermore, looking at the published measurements of the N805 and N800, it's possible to spot the same kinds of problems (differing only in degree). B&W need to address these problems in order to banish the synthetic, boxy quality that afflicts the N800 speakers.
PS: Look at Soundstage's measurements of the inexpensive B&W Model DM303. The on-axis frequency response is not flat but note how the off-axis response tracks the on-axis reponse to 75 degrees (there are no big timber changes). This speaker will sound a lot more coherent as a result of its smooth power response (the ratio of on and off axis response). If B&W can engineer this into their most inexpensive model, they could do the same with the top of the line N800 series.
Soundstage Measurements of DM303
http://www.soundstagemagazine.com/measurements/bw_dm303/Stereophile Measurements of N801
http://www.stereophile.com/showarchives.cgi?207:9Stereophile Measurements of N805:
http://www.stereophile.com/showarchives.cgi?168:7Stereophile Measurements of N800:
http://www.stereophile.com/showarchives.cgi?600:7
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- Re: Off-axis response - layman 13:58:01 07/24/02 (3)
- Re: Off-axis response - grblgrbl 09:18:45 07/25/02 (2)
- Re: Off-axis response - layman 13:02:43 07/25/02 (1)
- You are a marvelous wonder among lesser beings - grblgrbl 07:09:43 07/29/02 (0)
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2024, Audio Asylum, all rights reserved ]
