|
Hi-Rez Highway New high resolution SACD releases, players and technology. |
|
|
|
Hi-Rez Highway New high resolution SACD releases, players and technology. |
|
In Reply to: Re: Bass management or LFE low-pass filtering is required if using a sub posted by Christine Tham on December 2, 2005 at 21:12:08:
First of all, low frequency response appears to be extremely sensitive to listener position, and even presence of other objects in room (including number and position of humans within the room, and whether they are stationary or moving)For example, simply by moving the calibration mic to various locations on the sofa, and also doing measurements with me present and out of the room, gave dramatically different results. The main speakers (which are actually speced down to 35 Hz) actually has a usable bottom end that varies from 37 Hz to a sharp drop off below 80 Hz.
This means it's meaningless to fine tune the cross over point for bass management. Because if you set the cross over frequency based on the manufacturer provided spec of the speakers, there's no guarantee the response of those speakers in your room is anywhere close to published spec. Secondly, any fine tuning of cross over frequencies based on measured results will be highly sensitive to listener position. Unless you always listen to music by yourself, with your head in a clamp, the cross over setting will be almost certainly be non optimal during actual listening.
I now understand why THX recommends that the cross over setting be set at 80 Hz regardless of the frequency response of the speakers.
Secondly, response is also very sensitive to the layout of the room, which impacts room reflections. The "traditional" setting of two speakers with a blank wall behind them is optimal in terms of maximising sound reinforcement from reflections from the back wall, but also creates a highly non linear response due to combing interference. I found this out because the frequency response of my rear speakers (which are identical to my front speakers) were much smoother - this is because they are angled in approximate ITU configuration and fire across the room diagonally and the room reflections are much more complex and "averaged out".
Thirdly, the subwoofer doesn't really extend the bass that much. As I mentioned below, the lowest bass response from my main speakers range from as low as 37 Hz to as high as 80 Hz depending on listener position. My subwoofer on the other hand, only goes slightly lower, down to around 26 Hz or So. The difference between 37 and 26 Hz is hardly worth the trouble and the limitations of bass management.
Lastly, even though my room measurements show that I am listening to anything but a flat response, my ears tell me differently. According to my ears, I hear a flat response down to about 40 Hz from my main speakers (apart from a null point around 120 Hz). I suspect our ears condition themselves to non linear responses and adjust accordingly.
So maybe it's not that important after all to get a flat response (even +/- 10-20 dB!!!) as long as we minimize null points and combing interference.
Based on this, I would suggest that room treatment is far more important than bass management. Unfortunately, the level and sophistication of bass management (multiple cross over points etc.) is a big selling feature for high end surround processors, which lead unsophisticated consumers to think they actually offer a lot of benefit, whereas it seems to me (based on my measurements) the value of bass management on full range speakers is questionable (which I assume prospective purchasers of high end processors most likely have).
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- Some examples of "surprising" results I found for my room ... - Christine Tham 22:16:11 12/02/05 (0)
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2025, Audio Asylum, all rights reserved ]
